U.S. patent application number 11/337378 was filed with the patent office on 2006-07-27 for bellows pump.
This patent application is currently assigned to Nippon Pillar Packing Co., Ltd.. Invention is credited to Kazukiyo Teshima.
Application Number | 20060165541 11/337378 |
Document ID | / |
Family ID | 36696933 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060165541 |
Kind Code |
A1 |
Teshima; Kazukiyo |
July 27, 2006 |
Bellows Pump
Abstract
The present invention relates to, among bellows pumps for
transporting a liquid with using a bellows which axially extends
and contracts, a so-called internal-liquid type bellows pump in
which an air chamber is formed outside a bellows and a liquid to be
transported is sucked into the bellows. In order to prevent a pump
bellows, a piston or coupling plate, and a shaft coupling them from
being deviated from the same axis, prolong the life period of the
pump, maintain the pump performance for a long term, and realize
compactification and cost reduction of the pump, an external thread
is formed on the outer face of one end side of the shaft, an
engagement head is formed on the other end, a bottomed cylindrical
shaft screwed portion which is projected from a center portion of
the bottom into the pump bellows on the same axis, and which has an
internal thread on an inner face is disposed in a bottomed
cylindrical pump bellow, and the one end side of the shaft is
directly coupled with a center portion of the pump bellows by
thread joining.
Inventors: |
Teshima; Kazukiyo;
(Sanda-shi, JP) |
Correspondence
Address: |
KODA & ANDROLIA
2029 CENTURY PARK EAST
SUITE 1140
LOS ANGELES
CA
90067
US
|
Assignee: |
Nippon Pillar Packing Co.,
Ltd.
|
Family ID: |
36696933 |
Appl. No.: |
11/337378 |
Filed: |
January 23, 2006 |
Current U.S.
Class: |
417/472 |
Current CPC
Class: |
F04B 11/0016 20130101;
F04B 43/10 20130101; F04B 43/084 20130101 |
Class at
Publication: |
417/472 |
International
Class: |
F04B 45/02 20060101
F04B045/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 26, 2005 |
JP |
2005-017788 |
Claims
1. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, and one end side of
said shaft can be directly coupled with a center portion of said
pump bellows by thread joining.
2. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, and said shaft screwed portion has a length at
which a tip end side of said shaft screwed portion is always fitted
into said recess of said pump body.
3. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a center
hole through which said shaft is to be passed in a center portion
is disposed in said piston, said shaft is fitted into said center
hole in a contracting direction of said pump bellows, and an
annular sealing member which is made of an elastic material is
attached to a portion of said shaft which is to be fitted into said
center hole.
4. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a center
hole through which said shaft is to be passed in a center portion
is disposed in said piston, said shaft is fitted into said center
hole in a contracting direction of said pump bellows, and an
annular sealing member which is made of an elastic material is
attached to said center hole into which said shaft is to be
fitted.
5. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a stepped
center hole into which the other end of said shaft including said
engagement head can be fitted is disposed in said piston, said
shaft is fitted into said center hole in a contracting direction of
said pump bellows, and an annular sealing member which is made of
an elastic material is attached to a portion of said shaft which is
to be fitted into said center hole.
6. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a stepped
center hole into which the other end of said shaft including said
engagement head can be fitted is disposed in said piston, said
shaft is fitted into said center hole in a contracting direction of
said pump bellows, and an annular sealing member which is made of
an elastic material is attached to said center hole into which said
shaft is to be fitted.
7. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, said bellows pump comprises a coupling
plate which is coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a center
hole through which said shaft is to be passes is disposed in a
center portion of said coupling plate, said shaft is fitted into
said center hole in a contracting direction of said pump bellows,
and an annular sealing member which is made of an elastic material
is attached to a portion of said shaft which is to be fitted into
said center hole.
8. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, said bellows pump comprises a coupling
plate which is coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a center
hole through which said shaft is to be passed is disposed in a
center portion of said coupling plate, said shaft is fitted into
said center hole in a contracting direction of said pump bellows,
and an annular sealing member which is made of an elastic material
is attached to said center hole into which said shaft is to be
fitted.
9. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, said shaft screwed portion has a length at which
a tip end side of said shaft screwed portion is always fitted into
said recess of said pump body, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a center
hole through which said shaft is to be passed in a center portion
is disposed in said piston, said shaft is fitted into said center
hole in a contracting direction of said pump bellows, and an
annular sealing member which is made of an elastic material is
attached to a portion of said shaft which is to be fitted into said
center hole.
10. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, said shaft screwed portion has a length at which
a tip end side of said shaft screwed portion is always fitted into
said recess of said pump body, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a center
hole through which said shaft is to be passed in a center portion
is disposed in said piston, said shaft is fitted into said center
hole in a contracting direction of said pump bellows, and an
annular sealing member which is made of an elastic material is
attached to said center hole into which said shaft is to be
fitted.
11. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, said shaft screwed portion has a length at which
a tip end side of said shaft screwed portion is always fitted into
said recess of said pump body, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a stepped
center hole into which the other end of said shaft including said
engagement head can be fitted is disposed in said piston, said
shaft is fitted into said center hole in a contracting direction of
said pump bellows, and an annular sealing member which is made of
an elastic material is attached to a portion of said shaft which is
to be fitted into said center hole.
12. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, said shaft screwed portion has a length at which
a tip end side of said shaft screwed portion is always fitted into
said recess of said pump body, said bellows pump comprises a piston
which is to be coupled with said pump bellows by said shaft, an
engagement head having a diameter which is larger than a diameter
of said shaft is disposed in another end of said shaft, a stepped
center hole into which the other end of said shaft including said
engagement head can be fitted is disposed in said piston, said
shaft is fitted into said center hole in a contracting direction of
said pump bellows, and an annular sealing member which is made of
an elastic material is attached to said center hole into which said
shaft is to be fitted.
13. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, said shaft screwed portion has a length at which
a tip end side of said shaft screwed portion is always fitted into
said recess of said pump body, said bellows pump comprises a
coupling plate which is coupled with said pump bellows by said
shaft, an engagement head having a diameter which is larger than a
diameter of said shaft is disposed in another end of said shaft, a
center hole through which said shaft is to be passed is disposed in
a center portion of said coupling plate, said shaft is fitted into
said center hole in a contracting direction of said pump bellows,
and an annular sealing member which is made of an elastic material
is attached to a portion of said shaft which is to be fitted into
said center hole.
14. A bellows pump comprising a pump bellows which axially extends
and contracts, said bellows pump sucking a transported liquid by
extension of said pump bellows from a suction port of a pump body
into said pump bellows via a suction side check valve, and
discharging the transported liquid by contraction of said pump
bellows from a discharge port of said pump body via a discharge
side check valve, wherein said pump comprises a shaft which has an
external thread on an external face on one side, said pump bellows
has a bottomed cylindrical shape, a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into said pump bellows on a same axis, and which has an
internal thread on an inner face is disposed, one end side of said
shaft can be directly coupled with a center portion of said pump
bellows by thread joining, a recess is disposed in a center portion
of said pump body, said shaft screwed portion has a length at which
a tip end side of said shaft screwed portion is always fitted into
said recess of said pump body, said bellows pump comprises a
coupling plate which is coupled with said pump bellows by said
shaft, an engagement head having a diameter which is larger than a
diameter of said shaft is disposed in another end of said shaft, a
center hole through which said shaft is to be passed is disposed in
a center portion of said coupling plate, said shaft is fitted into
said center hole in a contracting direction of said pump bellows,
and an annular sealing member which is made of an elastic material
is attached to said center hole into which said shaft is to be
fitted.
15. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 3.
16. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 4.
17. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 5.
18. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 6.
19. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 9.
20. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 10.
21. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 11.
22. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; a pump unit
which is placed on one side of said pump body; and an accumulator
unit which is placed on another side of said pump body, said pump
unit comprising: a bottomed cylindrical pump bellows which is
placed so that an open end portion is joined to said pump body in
one side portion of said pump body to internally form a pump
chamber, and which can axially extend and contract; a pump cylinder
configured by a cylinder head portion which is placed opposingly to
said pump body in an axially outside of said pump bellows, a first
cylinder section which is projected on a same axis as said pump
bellows from said cylinder head portion toward said pump body so as
to internally accommodate said pump bellows, which is opposed in an
open end portion to said pump body across the open end portion of
said pump bellows, and which cooperates with said cylinder head
portion to form a pump air chamber outside said pump bellows, and a
second cylinder section which is projected on a same axis as said
pump bellows from said cylinder head portion toward a side opposite
to said first cylinder section, and into which a piston is axially
slidably fitted; a shaft which slidably passes through a center
portion of said cylinder head portion in an axial direction to
couple said pump bellows with said piston; and suction side and
discharge side check valves which are attached to said pump body in
said pump chamber, said pump bellows, said shaft, and said piston
being integrally reciprocated by air which is alternately supplied
to said pump air chamber and said second cylinder section, said
pump bellows repeatedly extending and contracting so that, when
said pump bellows extends, the transported liquid is sucked from a
suction port of said pump body into said pump chamber via said
suction side check valve, and, when said pump bellows contracts,
the transported liquid is discharged from a discharge port of said
pump body via said discharge side check valve, said accumulator
unit comprising: a bottomed cylindrical accumulator bellows which
is placed so that an open end portion is joined to the other side
portion of said pump body to internally form an accumulator chamber
for temporarily storing the transported liquid that is discharged
from said pump chamber via said discharge side check valve, and
which can axially extend and contract; and a bottomed cylindrical
accumulator cylinder which is placed outside said accumulator
bellows, which is opposed in the open end portion to said pump body
across said open end portion of said accumulator bellows, and which
forms an accumulator air chamber into which air is filled, outside
said accumulator bellows, pulsation of the discharge pressure of
said pump unit being absorbed by extension and contraction of said
accumulator bellows, said pump bellows, said shaft, and said piston
of said pump unit being coupled together by said coupling structure
of said pump bellows, said shaft, and said piston according to
claim 12.
23. A bellows pump according to claim 15, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
24. A bellows pump according to claim 16, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
25. A bellows pump according to claim 17, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
26. A bellows pump according to claim 18, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
27. A bellows pump according to claim 19, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
28. A bellows pump according to claim 20, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
29. A bellows pump according to claim 21, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
30. A bellows pump according to claim 22, wherein, in addition to
said pump body, said pump bellows, said suction side check valve,
said discharge side check valve, and said accumulator bellows which
are liquid-contacting components of said pump unit and said
accumulator unit, said pump cylinder, said piston, said shaft, and
said accumulator cylinder which are non-liquid-contacting
components are made of a resin material.
31. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 3.
32. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 4.
33. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 5.
34. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 6.
35. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 9.
36. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 10.
37. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 11.
38. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across the open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows, and a second cylinder section
which is projected on a same axis as said pump bellows from said
cylinder head portion toward a side opposite to said first cylinder
section, and into which a piston is axially slidably fitted; a
shaft which slidably passes through a center portion of said
cylinder head portion in an axial direction to couple said pump
bellows with said piston; and suction side and discharge side check
valves which are attached to said pump body in said pump chamber,
said pistons of said pump units being coupled together, suction
valve ports of said suction side check valves of said pump units
being communicatingly connected to said suction port of said pump
body, discharge valve ports of said discharge side check valves
being communicatingly connected to said discharge port, said pump
bellows, said shafts, and said pistons of said pump units being
integrally reciprocated in a same direction by air which is
alternately supplied to said second cylinder sections of said pump
units, said pump bellows of said pump units repeatedly extending
and contracting in an alternate manner so that, when one of said
pump units sucks by extension of said pump bellow the transported
liquid from said suction port of said pump body into said pump
chamber via said suction side check valve, said other pump unit
discharges by contraction of said pump bellow the transported
liquid from said discharge port of said pump body via said
discharge side check valve, said pump bellows, said shaft, and said
piston of each of said pump units being coupled together by said
coupling structure of said pump bellows, said shaft, and said
piston according to claim 12.
39. A bellows pump according to claim 31, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
40. A bellows pump according to claim 32, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
41. A bellows pump according to claim 33, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
42. A bellows pump according to claim 34, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
43. A bellows pump according to claim 35, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
44. A bellows pump according to claim 36, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
45. A bellows pump according to claim 37, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
46. A bellows pump according to claim 38, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders, said pistons, and said shafts which are
non-liquid-contacting components are made of a resin material.
47. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, and a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across an open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows; a shaft which slidably passes
through a center portion of said cylinder head portion in an axial
direction to couple one end with said pump bellows; a coupling
plate which is coupled with another end of said shaft; and suction
side and discharge side check valves which are attached to said
pump body in said pump chamber, said coupling plates of said pump
units being coupled together, suction valve ports of said suction
side check valves of said pump units being communicatingly
connected to said suction port of said pump body, discharge valve
ports of said discharge side check valves being communicatingly
connected to said discharge port, said pump bellows, said shafts,
and said coupling plates of said pump units being integrally
reciprocated in a same direction by air which is alternately
supplied to said pump chambers of same pump units, said pump
bellows repeatedly extending and contracting in an alternate manner
so that, when one of said pump units sucks by extension of said
pump bellow the transported liquid from said suction port of said
pump body into said pump chamber via said suction side check valve,
said other pump unit discharging by contraction of said pump bellow
the transported liquid from said discharge port of said pump body
via said discharge side check valve, said pump bellows, said shaft,
and said coupling plate of each of said pump units being coupled
together by said coupling structure of said pump bellows, said
shaft, and said coupling plate according to claim 7.
48. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, and a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across an open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows; a shaft which slidably passes
through a center portion of said cylinder head portion in an axial
direction to couple one end with said pump bellows; a coupling
plate which is coupled with another end of said shaft; and suction
side and discharge side check valves which are attached to said
pump body in said pump chamber, said coupling plates of said pump
units being coupled together, suction valve ports of said suction
side check valves of said pump units being communicatingly
connected to said suction port of said pump body, discharge valve
ports of said discharge side check valves being communicatingly
connected to said discharge port, said pump bellows, said shafts,
and said coupling plates of said pump units being integrally
reciprocated in a same direction by air which is alternately
supplied to said pump chambers of same pump units, said pump
bellows repeatedly extending and contracting in an alternate manner
so that, when one of said pump units sucks by extension of said
pump bellow the transported liquid from said suction port of said
pump body into said pump chamber via said suction side check valve,
said other pump unit discharging by contraction of said pump bellow
the transported liquid from said discharge port of said pump body
via said discharge side check valve, said pump bellows, said shaft,
and said coupling plate of each of said pump units being coupled
together by said coupling structure of said pump bellows, said
shaft, and said coupling plate according to claim 8.
49. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, and a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across an open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows; a shaft which slidably passes
through a center portion of said cylinder head portion in an axial
direction to couple one end with said pump bellows; a coupling
plate which is coupled with another end of said shaft; and suction
side and discharge side check valves which are attached to said
pump body in said pump chamber, said coupling plates of said pump
units being coupled together, suction valve ports of said suction
side check valves of said pump units being communicatingly
connected to said suction port of said pump body, discharge valve
ports of said discharge side check valves being communicatingly
connected to said discharge port, said pump bellows, said shafts,
and said coupling plates of said pump units being integrally
reciprocated in a same direction by air which is alternately
supplied to said pump chambers of same pump units, said pump
bellows repeatedly extending and contracting in an alternate manner
so that, when one of said pump units sucks by extension of said
pump bellow the transported liquid from said suction port of said
pump body into said pump chamber via said suction side check valve,
said other pump unit discharging by contraction of said pump bellow
the transported liquid from said discharge port of said pump body
via said discharge side check valve, said pump bellows, said shaft,
and said coupling plate of each of said pump units being coupled
together by said coupling structure of said pump bellows, said
shaft, and said coupling plate according to claim 13.
50. A bellows pump comprising: a pump body in which suction and
discharge ports for a transported liquid are formed; and a pair of
pump units which are placed on both sides of said pump body,
respectively, each of said pump units comprising: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to said pump body in one side portion of said
pump body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to said pump body in an axially
outside of said pump bellows, and a first cylinder section which is
projected on a same axis as said pump bellows from said cylinder
head portion toward said pump body so as to internally accommodate
said pump bellows, which is opposed in an open end portion to said
pump body across an open end portion of said pump bellows, and
which cooperates with said cylinder head portion to form a pump air
chamber outside said pump bellows; a shaft which slidably passes
through a center portion of said cylinder head portion in an axial
direction to couple one end with said pump bellows; a coupling
plate which is coupled with another end of said shaft; and suction
side and discharge side check valves which are attached to said
pump body in said pump chamber, said coupling plates of said pump
units being coupled together, suction valve ports of said suction
side check valves of said pump units being communicatingly
connected to said suction port of said pump body, discharge valve
ports of said discharge side check valves being communicatingly
connected to said discharge port, said pump bellows, said shafts,
and said coupling plates of said pump units being integrally
reciprocated in a same direction by air which is alternately
supplied to said pump chambers of same pump units, said pump
bellows repeatedly extending and contracting in an alternate manner
so that, when one of said pump units sucks by extension of said
pump bellow the transported liquid from said suction port of said
pump body into said pump chamber via said suction side check valve,
said other pump unit discharging by contraction of said pump bellow
the transported liquid from said discharge port of said pump body
via said discharge side check valve, said pump bellows, said shaft,
and said coupling plate of each of said pump units being coupled
together by said coupling structure of said pump bellows, said
shaft, and said coupling plate according to claim 14.
51. A bellows pump according to claim 47, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders and said shafts which are non-liquid-contacting
components are made of a resin material.
52. A bellows pump according to claim 48, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders and said shafts which are non-liquid-contacting
components are made of a resin material.
53. A bellows pump according to claim 49, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders and said shafts which are non-liquid-contacting
components are made of a resin material.
54. A bellows pump according to claim 50, wherein, in addition to
said pump bodies, said pump bellows, said suction side check
valves, and said discharge side check valves which are
liquid-contacting components of said pump units, said pump
cylinders and said shafts which are non-liquid-contacting
components are made of a resin material.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to, among bellows pumps for
transporting a liquid with using a bellows which axially extends
and contracts, a so-called internal-liquid type bellows pump in
which an air chamber is formed outside a bellows and a liquid to be
transported is sucked into the bellows.
[0003] 2. Description of the Prior Art
[0004] Conventionally, a bellows pump of such a kind is used as a
pump for transporting a liquid such as a chemical liquid, a
solvent, or pure water in a semiconductor manufacturing factory.
For example, bellows pumps of such a kind are classified into the
following two categories.
[0005] The first one is a bellows pump such as disclosed in
Japanese Patent Application Laying-Open No. 2001-317449. The
conventional bellows pump comprises: a pump body in which suction
and discharge ports for a liquid to be transported (hereinafter,
referred to as transported liquid) are formed; a pump unit which is
placed on one side of the pump body; and an accumulator unit which
is placed on the other side of the pump body. The pump unit
comprises: a bottomed cylindrical pump bellows which is placed so
that an open end portion is joined to one side portion of the pump
body to internally form a pump chamber, and which can axially
extend and contract; a pump cylinder configured by a cylinder head
portion which is placed opposingly to the pump body in the axially
outside of the pump bellows, a first cylinder section which is
projected on the same axis as the pump bellows from the cylinder
head portion toward the pump body so as to internally accommodate
the pump bellows, which is opposed in an open end portion to the
pump body across the open end portion of the pump bellows, and
which cooperates with the cylinder head portion to form a pump air
chamber outside the pump bellows, and a second cylinder section
which is projected on the same axis as the pump bellows from the
cylinder head portion toward the side opposite to the first
cylinder section, and into which a piston is axially slidably
fitted; a coupling shaft which slidably passes through a center
portion of the cylinder head portion in the axial direction to
couple the pump bellows with the piston; and suction side and
discharge side check valves which are attached to the pump body in
the pump chamber. The pump bellows, the coupling shaft, and the
piston are integrally reciprocated by air which is alternately
supplied to the pump air chamber and the second cylinder section.
The pump bellows repeatedly extends and contracts so that, when the
pump bellows extends, the transported liquid is sucked from the
suction port of the pump body into the pump chamber via the suction
side check valve, and, when the pump bellows contracts, the
transported liquid is discharged from the discharge port of the
pump body via the discharge side check valve. By contrast, the
accumulator unit comprises: a bottomed cylindrical accumulator
bellows which is placed so that an open end portion is joined to
another side portion of the pump body to internally form an
accumulator chamber for temporarily storing the transported liquid
that is discharged from the pump chamber via the discharge side
check valve, and which can axially extend and contract; and a
bottomed cylindrical accumulator cylinder which is placed outside
the accumulator bellows, which is opposed in an open end portion to
the pump body across the open end portion of the accumulator
bellows, and which forms an accumulator air chamber into which air
is filled, outside the accumulator bellows. Pulsation of the
discharge pressure of the pump unit is absorbed by extension and
contraction of the accumulator bellows.
[0006] The second one is a bellows pump such as disclosed in
Japanese Patent Application Laying-Open No. 2002-174180. The
conventional bellows pump comprises: a pump body in which suction
and discharge ports for a transported liquid are formed; and a pair
of pump units which are placed on both sides of the pump body,
respectively. Each of the pump units comprises: a bottomed
cylindrical pump bellows which is placed so that an open end
portion is joined to one side portion of the pump body to
internally form a pump chamber, and which can axially extend and
contract; a pump cylinder configured by a cylinder head portion
which is placed opposingly to the pump body in the axially outside
of the pump bellows, and a first cylinder section which is
projected on the same axis as the pump bellows from the cylinder
head portion toward the pump body so as to internally accommodate
the pump bellows, which is opposed in an open end portion to the
pump body across the open end portion of the pump bellows, and
which cooperates with the cylinder head portion to form a pump air
chamber outside the pump bellows; a coupling shaft which slidably
passes through a center portion of the cylinder head portion in the
axial direction to couple the one end with the pump bellows; a
coupling plate which is coupled with the other end of the coupling
shaft; and suction side and discharge side check valves which are
attached to the pump body in the pump chamber. The coupling plates
of the pump units are coupled together. Suction valve ports of the
suction side check valves of the pump units are communicatingly
connected to the suction port of the pump body, and discharge ports
of the discharge check valves are communicatingly connected to the
discharge port. The pump bellows, the coupling shafts, and the
coupling plates of the pump units are integrally reciprocated in
the same direction by air which is alternately supplied to the pump
chambers of the pump units. The pump bellows repeatedly extend and
contract in alternate manner so that, when the pump bellows of one
of the pumps extends and the transported liquid is sucked from the
suction port of the pump body into the pump chamber of the pump via
the suction side check valve, the pump bellows of the other pump
unit contracts and the transported liquid is discharged from the
discharge port of the pump body via the discharge side check
valve.
[0007] In both the conventional bellows pumps, flanges and bolts
which are made of a metal are used in coupling of the pump bellows
with the coupling shafts, and metal nuts and bolts are used in
coupling of the coupling shafts with the pistons or the coupling
plates.
[0008] In order to eliminate contamination caused by metal ions and
minimize contamination of a transported liquid due to a pump, a
countermeasure to form components by a resin is advancing. In some
pumps, liquid-contacting components, i.e., a pump body, a pump
bellows, a suction side check valve, a discharge side check valve,
and an accumulator bellows are made of a resin such as a
fluororesin. In other pumps, also a pump cylinder and an
accumulator cylinder which are non-liquid-contacting components are
made of a resin, and a coupling shaft which is a metal component of
a pump air chamber, and a flange and bolts which are used for
coupling a pump bellows with the coupling shaft are covered with a
resin, so that, even when the pump bellows or the accumulator
bellows is broken, corrosion or metal ion efflux due to immersion
does not occur.
SUMMARY OF THE INVENTION
[0009] In a conventional bellows pump, a flange and bolts are used
for coupling a pump bellows with a coupling shaft. When several of
the bolts are loosened or fastening torques of the bolts are
uneven, the axis of the pump bellows is deviated from that of the
coupling shaft, thereby causing the following problems. A sliding
portion of the coupling shaft is unevenly worn, and therefore the
life period of the pump is shortened. The sliding resistance is
increased, and therefore the pump performance is lowered. Moreover,
there is a fear that loosened bolts may slip off. In this case, the
pump fails to normally operate. Furthermore, the numbers of
components and assembly steps are increased, and the torques of
fastening portions must be managed. Therefore, there are further
problems such as that they may produce causes of impeding
improvement of the productivity of the pump, and cost
reduction.
[0010] Moreover, nuts and bolts are used in coupling of a coupling
shaft with a piston or a coupling plate. Therefore, a gap is
produced between the coupling shaft and the piston or the coupling
plate by dimensional tolerances. This gap may cause the coupling
shaft and the piston or the coupling plate to be fastened in a
state where their axes are deviated from each other. Therefore, a
sliding portion of the piston is unevenly worn, or the coupling
plate obliquely applies a load to the coupling shaft, so that a
sliding portion of the coupling shaft is unevenly worn, and the
life period of the pump is shortened. The sliding resistance is
increased, and therefore the pump performance is lowered. Moreover,
there is a fear that loosened bolts may slip off. In this case, the
pump fails to normally operate. Furthermore, the numbers of
components and assembly steps are increased, and the torques of
fastening portions must be managed. Therefore, there are further
problems such as that they may produce causes of impeding
improvement of the productivity of the pump, and cost
reduction.
[0011] It is a first object of the invention to provide a bellows
pump in which a shaft that is to couple a pump bellows with a
piston or a coupling plate can be coupled with the pump bellows on
the same axis without using a flange and a plurality of bolts,
whereby the life period of the pump can be prolonged, the pump
performance can be maintained for a long term, and compactification
and cost reduction of the pump can be realized. It is a second
object of the invention to provide a bellows pump in which a shaft
that is to couple a pump bellows with a piston or a coupling plate
can be coupled with the piston or the coupling plate on the same
axis without using nuts and bolts in the piston or the coupling
plate, whereby the life period of the pump can be prolonged, the
pump performance can be maintained for a long term, and
compactification and cost reduction of the pump can be
realized.
[0012] The bellows pump of the invention is a bellows pump that
comprises a pump bellows which axially extends and contracts, which
sucks a transported liquid by extension of the pump bellows from a
suction port of a pump body into the pump bellows via a suction
side check valve, and which discharges the transported liquid by
contraction of the pump bellows from a discharge port of the pump
body via a discharge side check valve, wherein one end side of a
shaft can be directly coupled with a center portion of the pump
bellows by thread joining.
[0013] Specifically, the pump comprises a shaft which has an
external thread on an external face on one side, the pump bellows
has a bottomed cylindrical shape, and a bottomed cylindrical shaft
screwed portion which is projected from a center portion of a
bottom into the pump bellows on a same axis, and which has an
internal thread on an inner face is disposed.
[0014] Preferably, a recess is disposed in a center portion of the
pump body, and the shaft screwed portion has a length at which a
tip end side of the shaft screwed portion is always fitted into the
recess of the pump body.
[0015] When the pump bellows and the piston are to be coupled
together by the shaft, preferably, an engagement head having a
diameter which is larger than a diameter of the shaft is disposed
in another end of the shaft, a center hole through which the shaft
is to be passed in a center portion is disposed in the piston, the
shaft is fitted into the center hole in a contracting direction of
the pump bellows, and an annular sealing member which is made of an
elastic material, such as an O-ring is attached to a portion of the
shaft which is to be fitted into the center hole. Alternatively,
the annular sealing member which is made of an elastic material may
be attached to the center hole into which the shaft is to be
fitted. More preferably, the center hole of the piston has a step
which allows the other end of the shaft including the engagement
head to be fitted into the hole.
[0016] When the pump bellows and the coupling plate are to be
coupled together by the shaft, preferably, an engagement head
having a diameter which is larger than a diameter of the shaft is
disposed in another end of the shaft, a center hole through which
the shaft is to be passed is disposed in a center portion of the
coupling plate, the shaft is fitted into the center hole in a
contracting direction of the pump bellows, and an annular sealing
member which is made of an elastic material such as an O-ring is
attached to a portion of the shaft which is to be fitted into the
center hole. Alternatively, the annular sealing member which is
made of an elastic material may be attached to the center hole into
which the shaft is to be fitted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a section view showing an internal structure of a
bellows pump of a first embodiment of the invention;
[0018] FIG. 2 is an enlarged view of a pump unit of the bellows
pump of FIG. 1;
[0019] FIG. 3 is a section view showing an internal structure of a
bellows pump of a second embodiment of the invention;
[0020] FIG. 4 is an enlarged view of one of pump units shown in
FIG. 3;
[0021] FIG. 5 is a section view showing an internal structure of a
bellows pump of a third embodiment of the invention; and
[0022] FIG. 6 is an enlarged view of one of pump units shown in
FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Hereinafter, embodiments of the invention will be described
with reference to the accompanying drawings. FIG. 1 is a section
view showing an internal structure of a bellows pump of a first
embodiment of the invention, and FIG. 2 is an enlarged view of a
pump unit shown in FIG. 1. The bellows pump 1 is used as a pump for
transporting a liquid such as a chemical liquid, a solvent, or pure
water in, for example, a semiconductor manufacturing factory, and
is configured by: a pump body 4 which is a substantially square
plate-like pump head, and in which suction and discharge ports 2
and 3 for the transported liquid are formed; a pump unit 5 which is
placed on one side (the right side in FIG. 1) of the pump body 4;
and an accumulator unit 6 which is placed on the other side (the
left side in FIG. 1) of the pump body 4.
[0024] A pump bellows 7 which can extend and contract in the axial
direction (the lateral direction in FIG. 1) is placed in one side
portion (the right side portion in FIG. 1) of the pump body 4. The
pump bellows 7 has a bottomed cylindrical shape which has a flange
portion in an open edge. The flange portion forms an annular
joining portion 8 in an open end portion, and is joined to the pump
body 4, and the bottom portion configures a disk-like movable plate
portion 9. The joining portion 8 and the movable plate portion 9
are integrally coupled with each other via a telescopic barrel
portion 10 which has a cylindrical accordion-like structure. The
pump bellows 7 and the pump body 4 form a cylindrical pump chamber
(pump liquid chamber) 11 which is hermetically sealed, and which
has a variable capacity. In the joining portion 8 of the pump
bellows 7, a circular recess 12 is formed concentrically with the
pump bellows 7 in a joining face with respect to the pump body 4,
and, in the pump body 4, a circular projection 13 which is to be
fitted into the recess 12 is formed concentrically with the pump
body 4 in a joining face with respect to the joining portion 8 of
the pump bellows 7. The recess 12 and the projection 13 which are
fitted to each other hermetically seal between the joining faces of
the pump bellows 7 and the pump body 4, and allow the pump bellows
7 to be placed on the same axis X as the pump body 4 while being
positioned in a radial direction.
[0025] In one side portion (the right side portion in FIG. 1) of
the pump body 4, a pump cylinder 14 which is a pump housing is
further placed on the same axis X as the pump bellows 7. The pump
cylinder 14 is configured by: a cylinder head portion 15 which is
placed opposingly to the pump body 4 in the axially outside (the
right outside of FIG. 1) of the pump bellows 7, and which has a
substantially same shape as the pump body 4; a cylindrical first
cylinder section 16 which is projected on the same axis X as the
pump bellows 7 from the cylinder head portion 15 toward the side of
the pump body 4 (the left side of FIG. 1) so as to internally
accommodate the pump bellows 7; and a cylindrical second cylinder
section 17 which is projected on the same axis X as the pump
bellows 7 from the cylinder head portion 15 toward the side
opposite to the first cylinder section 16 (the right side of FIG.
1). The first cylinder section 16 is opposed in an open end portion
to the pump body 4 across the open end portion (the joining portion
8) of the pump bellows 7, and cooperates with the cylinder head
portion 15 to form a pump air chamber 18 which is hermetically
sealed, outside the pump bellows 7. A piston 19 is slidably fitted
into the second cylinder section 17 in the axial direction (the
lateral direction in FIG. 1). The open end portion of the second
cylinder section 17 is closed by a cover 20 which is detachably
attached by bolting. A circular center hole 21 is formed in the
cylinder head portion 15. A pump shaft 22 which is placed on the
same axis X as the pump bellows 7, and which is a shaft having a
circular section slidably passes through the center hole 21 in the
axial direction (the lateral direction in FIG. 1). The pump bellows
7 and the piston 19 are coupled together by the pump shaft 22.
[0026] In the pump body 4, a suction side check valve 24 which
opens and closes a suction valve port 23 that communicates with the
suction port 2 for the transported liquid, and a discharge side
check valve 26 which opens and closes a discharge valve port 25
that communicates with the discharge port 3 for the transported
liquid are mounted in the pump chamber 11. In the joining portion
of the pump cylinder 14 with respect to the open end portion (the
joining portion 8) of the pump bellows 7, i.e., the open end
portion of the first cylinder section 16, an O-ring 27 which
hermetically seals therebetween is attached to the portion. In the
sliding portion of the pump cylinder 14 with respect to the pump
shaft 22, i.e., the periphery of the center hole 21 of the cylinder
head portion 15, an O-ring 29 which seals therebetween is attached
to the portion via a slipper ring 28. In the sliding portion of the
pump cylinder 14 with respect to the piston 19, i.e., the inner
face of the second cylinder section 17, an O-ring 31 which seals
therebetween is attached to the portion via a slipper ring 30. In
order to reciprocate the pump bellows 7, a bellows-contraction air
supply port 32 through which air is supplied to the pump chamber
18, and a bellows-expansion air supply port 33 through which air is
supplied to the interior of the second cylinder section 17 on the
side of the cylinder head 15 with respect to the attachment portion
of the O-ring 31 are formed in the cylinder head portion 15 of the
pump cylinder 14. A pair of proximity sensors 34, 35 which detect
the extension/contract stroke end positions of the pump bellows 7
in the reciprocating operation of the piston 19 are attached to the
second cylinder section 17 of the pump cylinder 14. Based on
outputs of the proximity sensors 34, 35, an air supplying circuit
which is provided between an air supply source (not shown) and the
air supply ports 32, 33 is switched so as to alternatingly supply
air to the pump chamber 11 and the second cylinder section 17.
Namely, switching of steps of sucking and discharging the
transported liquid by the bellows pump 1 is performed. The pump
unit 5 is configured by the above-described components on one side
portion (the right side portion in FIG. 1) of the pump body 4.
[0027] On the other hand, an accumulator bellows 36 which can
extend and contract in the axial direction (the lateral direction
in FIG. 1) is placed in the other side portion (the left side
portion in FIG. 1) of the pump body 4. The accumulator bellows 36
has a bottomed cylindrical shape which has a flange portion in an
open edge. The flange portion forms an annular joining portion 37
in an open end portion, and is joined to the pump body 4, and the
bottom portion configures a disk-like movable plate portion 38. The
joining portion 37 and the movable plate portion 38 are integrally
coupled with each other via the telescopic barrel portion 39 which
has a cylindrical accordion-like structure. The accumulator bellows
36 and the pump body 4 form a cylindrical accumulator chamber
(accumulator liquid chamber) 40 which is hermetically sealed, and
which has a variable capacity. The accumulator chamber 40 is
communicatingly connected to the pump chamber 11 via the discharge
side check valve 26 and a communication path 41 formed in the pump
body 4, and communicates with the discharge port 3 formed in the
pump body 4, so as to temporarily store the transported liquid that
is discharged from the pump chamber 11 via the discharge side check
valve 26. In the joining portion 37 of the accumulator bellows 36,
a circular recess 42 is formed concentrically with the accumulator
bellows 36 in a joining face with respect to the pump body 4, and,
in the pump body 4, a circular projection 43 which is to be fitted
into the recess 42 is formed concentrically with the pump body 4 in
a joining face with respect to the joining portion 37 of the
accumulator bellows 36. The recess 42 and the projection 43 which
are fitted to each other hermetically seal between the joining
faces of the accumulator bellows 36 and the pump body 4, and allows
the accumulator bellows 36 to be placed on the same axis X as the
pump body 4 while being positioned in a radial direction, so that
it is placed on the same axis X as the pump bellows 7.
[0028] In the other side portion (the left side portion in FIG. 1)
of the pump body 4, an accumulator cylinder 44 which is an
accumulator housing is further placed on the same axis X as the
accumulator bellows 36. In the accumulator cylinder 44 having a
bottomed cylindrical shape, the bottom portion configures a
cylinder head portion 45 which is placed opposingly to the pump
body 4 in the axially outside (the left outside of FIG. 1) of the
accumulator bellows 36, and which has a substantially same shape as
the pump body 4, and the barrel portion configures a cylindrical
cylinder section 46 which is projected so as to internally
accommodate the accumulator bellows 36, from the cylinder head
portion 45 to the side of the pump body 4 (the right side in FIG.
1) on the same axis X as the accumulator bellows 36. The cylinder
section 46 is opposed in an open end portion to the pump body 4
across the open end portion (the joining portion 37) of the
accumulator bellows 36, and cooperates with the cylinder head
portion 45 to form an accumulator air chamber 47 which is filled
with air for reducing pulsation, and which is hermetically sealed,
outside the accumulator bellows 36. In the joining portion of the
accumulator cylinder 44 with respect to the open end portion (the
joining portion 37) of the accumulator bellows 36, i.e., the open
end portion of the cylinder section 46, an O-ring 57 which
hermetically seals therebetween is attached to the portion. A
stopper 48 for restricting excess extending deformation of the
accumulator bellows 36 to prevent the bellows from being broken is
projected from the inner face of the accumulator cylinder 44. An
automatic pressure adjusting mechanism 49 which is configured by an
automatic air supply valve mechanism and an automatic air discharge
valve mechanism, and which controls the air pressure in the
accumulator air chamber 47 to balance with the discharge pressure
of the pump unit 5 in accordance with variations of the pressure is
attached to the accumulator cylinder 44. The accumulator unit 6 is
configured by the above-described components on the other side
portion (the left side portion in FIG. 1) of the pump body 4 on the
same axis X as the pump unit 5.
[0029] The cylinder head portions 15, 45 which are on both the
sides of the pump body 4 are fastened together with using plural
metal tie rods 50 which are in parallel to the axis X, thereby
configuring the bellows pump 1 in which the pump body 4, the pump
unit 5, and the accumulator unit 6 are integrated. In this case,
the tie rods 50 (including metal nuts 51 and the like on both the
ends) are passed through and accommodated in flanges 52, 53, 54
which are formed on the outer faces of the pump body 4, the pump
cylinder 14, and the accumulator cylinder 44, and which are joined
together in series. Openings of both the ends of the accommodating
portions are closed by detachable caps 55, 56, so as to prevent
metal parts such as the tie rods 50 and the nuts 51 in both the
ends from being corroded because of immersion. Alternatively, the
pump body 4 is formed into a circular plate-like shape, an external
thread is formed on both the side portions of the outer peripheral
face, and nut portions which have on the inner face an internal
thread to be screwed with the external thread are integrally formed
in the open end portions of the cylinder sections 16, 46. The pump
cylinder 14 and the accumulator cylinder 44 are directly coupled by
means of thread coupling to both the ends of the pump body 4,
respectively, thereby configuring the bellows pump 1 in which the
pump body 4, the pump unit 5, and the accumulator unit 6 are
integrated.
[0030] Next, the operation of the thus configured bellows pump 1
will be described. The suction port 2 of the pump body 4
communicates with the pump chamber 11 via a suction passage 2a and
the suction side check valve 24, the pump chamber 11 communicates
with the accumulator chamber 40 via the discharge side check valve
26 and the communication path 41, and the accumulator chamber 40
communicates with the discharge port 3 of the pump body 4 via a
discharge passage 3a. In the pump unit 5, when air is supplied from
the air supply source into the second cylinder section 17 through
the air supply port 33 (at this time, the air supply port 32 is
opened to the atmosphere), the pressure on the side of the cylinder
head portion 15 becomes higher than that on the side of the piston
19 in the second cylinder 17. Therefore, the piston 19 moves toward
the right side in FIG. 1, and, integrally with this movement, also
the pump shaft 22 and the movable plate portion 9 of the pump
bellows 7 move toward the right side in FIG. 1, or that is, the
pump bellows 7 extends. As a result of the extending operation of
the pump bellows 7, the suction side check valve 24 is opened, the
discharge side check valve 26 is closed, and hence the transported
liquid is sucked from the suction port 2 of the pump body 4 into
the pump chamber 11 via the suction passage 2a and the suction side
check valve 24 (a suction step). Subsequently, air is supplied from
the air supply source into the pump air chamber 18 via the air
supply port 32 (at this time, the air supply port 32 is opened to
the atmosphere), the pressure of the pump air chamber 18 is raised,
and hence the pump bellows 7 contracts. As a result of the
contracting operation of the pump bellows 7, the suction side check
valve 24 is closed, the discharge side check valve 26 is opened,
and therefore the transported liquid in the pump chamber 11 is
discharged via the discharge side check valve 26. When the pump
bellows 7 contracts, the pump shaft 22 and the piston 19 move
integrally with this movement toward the left side in FIG. 1 (a
discharge step). The above-described operations are repeated by a
switching control of the steps of sucking and discharging the
transported liquid, thereby performing a pump action.
[0031] On the other hand, in the accumulator unit 6, the
accumulator chamber 40 receives via the communication path 41 the
transported liquid discharged from the pump chamber 11, and the
liquid is temporarily stored in the accumulator chamber 40, and
then discharged from the discharge port 3 of the pump body 4 via
the discharge passage 3a. At this time, when the discharge pressure
of the pump unit 5 is in a peak portion of the discharge pressure
curve as a result of pulsation of the discharge pressure, the
accumulator bellows 36 extends so as to increase the capacity of
the accumulator chamber 40. The flow quantity of the transported
liquid flowing out from the accumulator chamber 40 because of the
extending operation becomes smaller than that of the flowing-in
liquid. By contrast, when the discharge pressure comes to a valley
portion of the discharge pressure curve, the discharge pressure
becomes lower than the air filling pressure of the accumulator air
chamber 47 which is compressed in accordance with the extension of
the accumulator bellows 36, and hence the accumulator bellows 36
contracts so that the capacity of the accumulator chamber 40 is
reduced. The flow quantity of the transported liquid flowing out
from the accumulator chamber 40 because of the contracting
operation becomes larger than that of the flowing-in liquid. The
above-described operations are repeated in accordance with the
steps of sucking and discharging the transported liquid by the pump
unit 5, thereby performing a damper action.
[0032] Because of the pump action of the pump unit 5 and the damper
action of the accumulator unit 6, the bellows pump 1 performs
liquid transportation while sucking the transported liquid from the
suction port 2 of the pump body 4, and continuously discharging the
transported liquid from the discharge port 3 in an approximately
constant flow quantity at a discharge pressure which is
substantially smoothed as a result of absorption and attenuation of
pulsation.
[0033] As apparent from the above description, in summary, the
bellows pump 1 of the first embodiment comprises: the pump body 4
in which the suction and discharge ports 2 and 3 for the
transported liquid are formed; the pump unit 5 which is placed on
one side of the pump body 4; and the accumulator unit 6 which is
placed on the other side of the pump body. The pump unit 5
comprises: the bottomed cylindrical pump bellows 7 which is placed
so that the open end portion 8 is joined to the pump body 4 in one
side portion of the pump body 4 to internally form the pump chamber
11, and which can axially extend and contract; the pump cylinder 14
configured by the cylinder head portion 15 which is placed
opposingly to the pump body 4 in the axially outside of the pump
bellows 7, the first cylinder section 16 which is projected on the
same axis X as the pump bellows 7 from the cylinder head portion 15
toward the pump body 4 so as to internally accommodate the pump
bellows 7, which is opposed in the open end portion to the pump
body 4 across the open end portion 8 of the pump bellows 7, and
which cooperates with the cylinder head portion 15 to form the pump
air chamber 18 outside the pump bellows 7, and the second cylinder
section 17 which is projected on the same axis X as the pump
bellows 7 from the cylinder head portion 15 toward the side
opposite to the first cylinder section 16, and into which the
piston 19 is axially slidably fitted; the pump shaft 22 which
slidably passes through a center portion of the cylinder head
portion 15 in the axial direction to couple the pump bellows 7 with
the piston 19; and the suction side and discharge side check valves
24 and 26 which are attached to the pump body 4 in the pump chamber
11. The pump bellows 7, the pump shaft 22, and the piston 19 are
integrally reciprocated by air which is alternately supplied to the
pump air chamber 18 and the second cylinder section 17. The pump
bellows 7 repeatedly extends and contracts so that, when the pump
bellows 7 extends, the transported liquid is sucked from the
suction port 2 of the pump body 4 into the pump chamber 11 via the
suction side check valve 24, and, when the pump bellows contracts,
the transported liquid is discharged from the discharge port 3 of
the pump body 4 via the discharge side check valve 26. By contrast,
the accumulator unit 6 comprises: the bottomed cylindrical
accumulator bellows 36 which is placed so that the open end portion
37 is joined to the other side portion of the pump body 4 to
internally form the accumulator chamber 40 for temporarily storing
the transported liquid that is discharged from the pump chamber 11
via the discharge side check valve 26, and which can axially extend
and contract; and a bottomed cylindrical accumulator cylinder 44
which is placed outside the accumulator bellows 36, which is
opposed in the open end portion to the pump body 4 across the open
end portion 37 of the accumulator bellows 36, and which forms an
accumulator air chamber 40 into which air is filled, outside the
accumulator bellows 36. Pulsation of the discharge pressure of the
pump unit 5 is absorbed by extension and contraction of the
accumulator bellows 36.
[0034] Among the components of the bellows pump 1 of the first
embodiment, in addition to the pump body 4, the pump bellows 7, the
suction side check valve (including a valve case and a spring) 24,
the discharge side check valve (including a valve case and a
spring) 26, and the accumulator bellows 36 which are the
liquid-contacting components of the pump unit 5 and the accumulator
unit 6, also the pump cylinder 14, the piston 19, the pump shaft
22, and the accumulator cylinder 44 which are non-liquid-contacting
components are made of a resin consisting of a resin material.
Namely, the bellows pump 1 is made of a resin or resinified.
[0035] Preferable materials for resinification are as follows. With
regard to the pump body 4, the pump bellows 7, the slipper rings
28, 30, the accumulator bellows 36, and the valve cases of the
suction side check valve 24 and the discharge side check valve 26,
a fluororesin such as PTFE (polytetrafluoroethylen) is preferably
used. With regard to the valve elements and springs of the suction
side check valve 24 and the discharge side check valve 26, a
fluororesin such as PFA (polytetrafluoroethylene-perfluoroalkyl
vinyl ether copolymer) is preferably used. With regard to the pump
cylinder 14, the cover 20, the accumulator cylinder 44, and the
body 49a of the automatic pressure adjusting mechanism 49, a resin
such as PP (polypropylene) is preferably used. With regard to the
pump shaft 22 and the piston 19, a resin such as PSP (polyphenylene
sulfide) is preferably used. With regard to the caps 55, 56, a
resin such as PE (polyethylene) is preferably used. The O-rings 27,
29, 31, 57 and all other O-rings which are used in the bellows pump
1 are made of fluoro rubber.
[0036] Next, a bellows pump of a second embodiment of the invention
will be described with reference to FIGS. 3 and 4. FIG. 3 is a
section view showing an internal structure of the bellows pump of
the second embodiment of the invention, and FIG. 4 is an enlarged
view of one of pump units shown in FIG. 3. Also the bellows pump 58
is used as a pump for transporting a liquid such as a chemical
liquid, a solvent, or pure water in, for example, a semiconductor
manufacturing factory, and generally configured with disposing the
pump unit 5 of the bellows pump 1 of the first embodiment in each
side of the pump body 4. The components which are identical with
those of the bellows pump 1 of the first embodiment are denoted by
the same reference numerals, and their detailed description is
omitted. Different portions will be described.
[0037] The bellows pump 58 of the second embodiment is configured
by the pump body 4, and a pair of pump units 5 which are placed on
both sides (the right and left sides in FIG. 3) of the pump body 4
on the same axis X, respectively. In each of the pump units 5, the
piston 19 is formed to have a diameter which is larger than the
outer diameter of the first cylinder section 16 of the pump
cylinder 14, and, in accordance with this, also the second cylinder
section 17 is formed to have a diameter which is larger than the
outer diameter of the first cylinder section 16. The pistons 19 of
the pump units 5 are fastened together by plural metal tie rods 59
which are in parallel to the axis X, in the radially outer side of
the first cylinder sections 16. In each of the tie rods 59, steps
59a, 59b are formed in end portions, respectively. The steps 59a,
59b enable the pistons 19 of the pump units 5 to be coupled
together with maintaining a predetermined distance between the
pistons. The intermediate portions of the tie rods are slidably
passed through and accommodated in flanges 60 in the axial
direction (in the lateral direction in FIG. 3). The flanges are
formed on the outer faces of the pump cylinders 14 of the pump
units 5, and joined together in series. Small-diameter end portions
which are outside the steps 59a, 59b are passed through the pistons
19, and projected toward the covers 20 for the pistons 19. Metal
nuts 61 are screwed to the end portions of the tie rods 59 which
are projected toward the covers 20 for the pistons 19. In the
sliding portions of the flanges 60 with respect to the tie rods 59,
i.e., the peripheries of openings of holes 62 on the side of the
cylinder head portion 15, O-rings 64 which seal therebetween are
attached to the portions via slipper rings 63, respectively. The
tie rods 59 are passed through the holes 62. O-rings 66
hermetically seal between the tie rods 59 and hole 65 for the
pistons 19.
[0038] The suction port 2 of the pump body 4 communicates with the
suction valve ports 23 of the suction side check valves 24 of the
pump units 5, and the discharge port 3 communicates with the
discharge valve ports 25 of the discharge side check valves 26 of
the pump units 5. Only the air supply port 33 through which air is
supplied to the interior of the second cylinder section 17 on the
side of the cylinder head 15 with respect to the attachment portion
of the O-ring 31 is formed in each of the cylinder head portions 15
of the pump cylinders 14 of the pump units 5. A pair of proximity
sensors 34, 35 are distributedly disposed in the pump units 5, and
attached to the covers 20, respectively. The sensors are placed in
positions where stroke ends of the pistons 19 along the extension
direction of the pump bellows 7 are detected. Based on outputs of
the proximity sensors 34, 35, an air supplying circuit which is
provided between an air supply source (not shown) and the air
supply ports 33 of the pump units 5 is switched so as to
alternatingly supply air to the second cylinder sections 17 of the
pump units 5. Namely, switching of steps of sucking and discharging
the transported liquid by the bellows pump 58 is performed.
[0039] The bellows pump 58 in which the pump body 4 and the pair of
the pump units 5 are integrated is configured by fastening the
cylinder head portions 15 on both the sides of the pump body 4 with
using the plural metal tie rods 50 which are in parallel to the
axis X.
[0040] Next, the operation of the thus configured bellows pump 58
will be described. In the following description, the pump unit 5 on
the left side in FIG. 3 is referred to as "left pump unit", and the
components of the left pump unit 5 are referred with affixing
"left" to their names. By contrast, the pump unit 5 on the right
side in FIG. 3 is referred to as "right pump unit", and the
components of the right pump unit 5 are referred with affixing
"right" to their names. The suction port 2 of the pump body 4
communicates with the right and left pump chambers 11 via the right
and left suction side check valves 24, and the right and left pump
chambers 11 communicate with the discharge port 3 of the pump body
4 via the right and left discharge side check valves 26. When air
is supplied from the air supply source into the left second
cylinder section 17 through the left air supply port 33 (at this
time, the right air supply port 33 is opened to the atmosphere),
the pressure of the left cylinder head portion 15 becomes higher
than that of the left piston 19 in the left second cylinder 17.
Therefore, the left piston 19 moves toward the left side in FIG. 3,
and, integrally with this movement, also the left pump shaft 22 and
the movable plate portion 9 of the left pump bellows 7 move toward
the left side in FIG. 3, or that is, the left pump bellows 7 of the
left pump unit 5 extends. The extending operation of the left pump
bellows 7 is transmitted from the left piston 19 to the right
piston 19 of the right pump unit 5 via the tie rods 59. The right
piston 19 moves toward the left side in FIG. 3, and, integrally
with this movement, also the right pump shaft 22 and the movable
plate portion 9 of the right pump bellows 7 move toward the left
side in FIG. 3, or that is, the right pump bellows 7 of the right
pump unit 5 contracts. As a result of this operation, the left
suction side check valve 24 is opened, the left discharge side
check valve 26 is closed, the right suction side check valve 24 is
closed, and the right discharge side check valve 26 is opened.
Therefore, the transported liquid is sucked from the suction port 2
of the pump body 4 into the left pump chamber 11 via the left
suction side check valve 24 (a suction step of the left pump unit
5), and the transported liquid in the right pump chamber 11 is
discharged from the discharge port 3 of the pump body 4 via the
right discharge side check valve 26 (a discharge step of the right
pump unit 5). Subsequently, when air is supplied from the air
supply source into the right second cylinder section 17 through the
right air supply port 33 (at this time, the left air supply port 33
is opened to the atmosphere), the pressure of the right cylinder
head portion 15 becomes higher than that of the right piston 19 in
the right second cylinder 17. Therefore, the right piston 19 moves
toward the right side in FIG. 3, and, integrally with this
movement, also the right pump shaft 22 and the movable plate
portion 9 of the right pump bellows 7 move toward the right side in
FIG. 3, or that is, the right pump bellows 7 of the right pump unit
5 extends. The extending operation of the right pump bellows 7 is
transmitted from the right piston 19 to the left piston 19 of the
left pump unit 5 via the tie rods 59. The left piston 19 moves
toward the right side in FIG. 3, and, integrally with this
movement, also the left pump shaft 22 and the movable plate portion
9 of the left pump bellows 7 move toward the right side in FIG. 3,
or that is, the left pump bellows 7 of the left pump unit 5
contracts. As a result of this operation, the right suction side
check valve 24 is opened, the right discharge side check valve 26
is closed, the left suction side check valve 24 is closed, and the
left discharge side check valve 26 is opened. Therefore, the
transported liquid is sucked from the suction port 2 of the pump
body 4 into the right pump chamber 11 via the right suction side
check valve 24 (a suction step of the right pump unit 5), and the
transported liquid in the left pump chamber 11 is discharged from
the discharge port 3 of the pump body 4 via the left discharge side
check valve 26 (a discharge step of the left pump unit 5). The
above-described operations are repeated by a switching control of
the steps of sucking and discharging the transported liquid in the
bellows pump 58, thereby performing a pump action.
[0041] Because of the above-described pump action in which the
paired right and left pump units 5 alternately perform the suction
step and the discharge step, the bellows pump 58 performs liquid
transportation while sucking the transported liquid from the
suction port 2 of the pump body 4, and discharging the transported
liquid from the discharge port 3. When a single accumulator having
a structure and function which are similar to those of the
accumulator unit 6 of the bellows pump 1 of the first embodiment is
added to the discharge side of the bellows pump 58, pulsation of
the discharge pressure of the bellows pump 58 is absorbed and
attenuated to be substantially smoothed, whereby liquid
transportation can be continuously performed at an approximately
constant flow quantity.
[0042] As apparent from the above description, in summary, the
bellows pump 58 of the second embodiment comprises: the pump body 4
in which the suction and discharge ports 2 and 3 for the
transported liquid are formed; and the pair of pump units 5 which
are placed on both sides of the pump body 4, respectively. Each of
the pump units 5 comprises: the bottomed cylindrical pump bellows 7
which is placed so that the open end portion 8 is joined to the
pump body 4 in one side portion of the pump body 4 to internally
form the pump chamber 11, and which can axially extend and
contract; the pump cylinder 14 configured by the cylinder head
portion 15 which is placed opposingly to the pump body 4 in the
axially outside of the pump bellows 7, the first cylinder section
16 which is projected on the same axis X as the pump bellows 7 from
the cylinder head portion 15 toward the pump body 4 so as to
internally accommodate the pump bellows 7, which is opposed in the
open end portion to the pump body 4 across the open end portion 8
of the pump bellows 7, and which cooperates with the cylinder head
portion 15 to form the pump air chamber 18 outside the pump bellows
7, and the second cylinder section 17 which is projected on the
same axis X as the pump bellows 7 from the cylinder head portion 15
toward the side opposite to the first cylinder section 16, and into
which the piston 19 is axially slidably fitted; the pump shaft 22
which slidably passes through a center portion of the cylinder head
portion 15 in the axial direction to couple the pump bellows 7 with
the piston 19; and the suction side and discharge side check valves
24 and 26 which are attached to the pump body 4 in the pump chamber
11. The pistons 19 of the pump units 5 are coupled together, the
suction valve ports 23 of the suction side check valves 24 of the
pump units 5 are communicatingly connected to the suction port 2 of
the pump body 4, and the discharge valve ports 25 of the discharge
side check valves 26 are communicatingly connected to the discharge
port 3. The pump bellows 7, the pump shafts 22, and the pistons 19
of the pump units 5 are integrally reciprocated in the same
direction by air which is alternately supplied to the second
cylinder sections 17 of the pump units 5. The pump bellows 7 of the
pump units 5 repeatedly extend and contract in an alternate manner
so that, when one of the pump units 5 sucks by extension of the
pump bellow 7 the transported liquid from the suction port 2 of the
pump body 4 into the pump chamber 11 via the suction side check
valve 24, the other pump unit 5 discharges by contraction of the
pump bellow 7 the transported liquid from the discharge port 3 of
the pump body 4 via the discharge side check valve 26.
[0043] Also the bellows pump 58 of the second embodiment is
resinified in the same manner as the bellows pump 1 of the first
embodiment.
[0044] Next, a bellows pump of a third embodiment of the invention
will be described with reference to FIGS. 5 and 6. FIG. 5 is a
section view showing an internal structure of a bellows pump of the
third embodiment of the invention, and FIG. 6 is an enlarged view
of one of pump units shown in FIG. 5. Also the bellows pump 67 is
used as a pump for transporting a liquid such as a chemical liquid,
a solvent, or pure water in, for example, a semiconductor
manufacturing factory, and generally configured with disposing the
pump unit 5 of the bellows pump 1 of the first embodiment in each
side of the pump body 4, or that is, has the same structure as the
bellows pump 58 of the second embodiment. The components which are
identical with those of the bellows pump 58 of the second
embodiment are denoted by the same reference numerals, and their
detailed description is omitted. Different portions will be
described.
[0045] The bellows pump 67 of the third embodiment is configured by
the pump body 4, and a pair of pump units 5 which are placed on
both sides (the right and left sides in FIG. 5) of the pump body 4
on the same axis X, respectively. In each of the pump units 5, the
pump cylinder 14 is not provided with the second cylinder section
17. In accordance with this, the cover 20 is directly attached in a
detachable manner to the cylinder head portion 15 by bolting to
cover the piston portion, and the pistons 19 of the bellows pump 58
of the second embodiment are formed simply as disk-like coupling
plates 68 which couple the pump shafts 22 of both the pump units 5
via the tie rods 59. Only the bellows-extension air supply port 32
for supplying air to the pump air chamber 18 is formed in the
cylinder head portion 15 of the pump cylinder 14 of each of the
pump units 5. Based on outputs of the proximity sensors 34, 35, an
air supplying circuit which is provided between an air supply
source (not shown) and the air supply ports 32 of the pump units 5
is switched so as to alternatingly supply air to the pump chambers
18 of the pump units 5. Namely, switching of steps of sucking and
discharging the transported liquid by the bellows pump 67 is
performed.
[0046] The bellows pump 67 in which the pump body 4 and the pair of
the pump units 5 are integrated is configured by fastening the
cylinder head portions 15 on both the sides of the pump body 4 with
using the plural metal tie rods 50 which are in parallel to the
axis X.
[0047] Next, the operation of the thus configured bellows pump 67
will be described. In the following description also, the pump unit
5 on the left side in FIG. 5 is referred to as "left pump unit",
and the components of the left pump unit 5 are referred with
affixing "left" to their names. By contrast, the pump unit 5 on the
right side in FIG. 5 is referred to as "right pump unit", and the
components of the right pump unit 5 are referred with affixing
"right" to their names. The suction port 2 of the pump body 4
communicates with the right and left pump chambers 11 via the right
and left suction side check valves 24, and the right and left pump
chambers 11 communicate with the discharge port 3 of the pump body
4 via the right and left discharge side check valves 26. When air
is supplied from the air supply source into the right pump air
chamber 18 through the right air supply port 32 (at this time, the
left air supply port 32 is opened to the atmosphere), the pressure
of the right pump air chamber 18 is raised, and hence the right
pump bellows 7 contracts. As a result of the contract operation of
the right pump bellows 7, the right suction side check valve 24 is
closed, and the right discharge side check valve 26 is opened.
Therefore, the transported liquid in the right pump chamber 11 is
discharged from the discharge port 3 of the pump body 4 via the
right discharge side check valve 26 (a discharge step of the right
pump unit 5). When the right pump bellows 7 contracts, the right
pump shaft 22 and the right coupling plate 68 move integrally with
this movement toward the left side in FIG. 5. The contracting
operation of the right pump bellows 7 is transmitted from the right
coupling plate 68 to the left coupling plate 68 of the left pump
unit 5 via the tie rods 59. The left coupling plate 68 moves toward
the left side in FIG. 5, also the left pump shaft 22 and the
movable plate portion 9 of the left pump bellows 7 move integrally
with this movement toward the left side in FIG. 5, or that is, the
left pump bellows 7 of the left pump unit 5 extends. As a result of
this operation, the left suction side check valve 24 is opened, and
the left discharge side check valve 26 is closed. Therefore, the
transported liquid is sucked from the suction port 2 of the pump
body 4 into the left pump chamber 11 via the left suction side
check valve 24 (a suction step of the left pump unit 5).
Subsequently, when air is supplied from the air supply source into
the left pump air chamber 18 through the left air supply port 32
(at this time, the right air supply port 32 is opened to the
atmosphere), the pressure of the left pump air chamber 18 is
raised, and hence the left pump bellows 7 contracts. As a result of
the contracting operation of the left pump bellows 7, the left
suction side check valve 24 is opened, and the left discharge side
check valve 26 is closed. The transported liquid in the left pump
chamber 11 is discharged from the discharge port 3 of the pump body
4 via the left discharge side check valve 26 (a discharge step of
the left pump unit 5). When the left pump bellows 7 contracts, the
left pump shaft 22 and the left coupling plate 68 move integrally
with this movement toward the right side in FIG. 5. The contracting
operation of the left pump bellows 7 is transmitted from the left
coupling plate 68 to the right coupling plate 68 of the right pump
unit 5 via the tie rods 59. The right coupling plate 68 moves
toward the right side in FIG. 5, and also the right pump shaft 22
and the movable plate portion 9 of the right pump bellows 7 move
integrally with this movement toward the right side in FIG. 5, or
that is, the right pump bellows 7 of the right pump unit 5 extends.
As a result of this operation, the right suction side check valve
24 is opened, and the right discharge side check valve 26 is
closed. Therefore, the transported liquid is sucked from the
suction port 2 of the pump body 4 into the right pump chamber 11
via the right suction side check valve 24 (a suction step of the
right pump unit 5). The above-described operations are repeated by
a switching control of the steps of sucking and discharging the
transported liquid in the bellows pump 67, thereby performing a
pump action.
[0048] Because of the above-described pump action in which the
paired right and left pump units 5 alternately perform the suction
step and the discharge step, the bellows pump 67 performs liquid
transportation while sucking the transported liquid from the
suction port 2 of the pump body 4, and discharging the transported
liquid from the discharge port 3. When a single accumulator having
a structure and function which are similar to those of the
accumulator unit 6 of the bellows pump 1 of the first embodiment is
added to the discharge side of the bellows pump 67, pulsation of
the discharge pressure of the bellows pump 67 is absorbed and
attenuated to be substantially smoothed, whereby liquid
transportation can be continuously performed at an approximately
constant flow quantity.
[0049] As apparent from the above description, in summary, the
bellows pump 67 of the third embodiment comprises: the pump body 4
in which suction and discharge ports 2 and 3 for the transported
liquid are formed; and the pair of pump units 5 which are placed on
both sides of the pump body 4, respectively. Each of the pump units
5 comprises: the bottomed cylindrical pump bellows 7 which is
placed so that the open end portion 8 is joined to the pump body 4
in one side portion of the pump body 4 to internally form the pump
chamber 11, and which can axially extend and contract; the pump
cylinder 14 configured by the cylinder head portion 15 which is
placed opposingly to the pump body 4 in the axially outside of the
pump bellows 7, and the first cylinder section 16 which is
projected on the same axis X as the pump bellows 7 from the
cylinder head portion 15 toward the pump body 4 so as to internally
accommodate the pump bellows 7, which is opposed in the open end
portion to the pump body 4 across the open end portion 8 of the
pump bellows 7, and which cooperates with the cylinder head portion
15 to form the pump air chamber 18 outside the pump bellows 7; the
pump shaft 22 which slidably passes through a center portion of the
cylinder head portion 15 in the axial direction to couple one end
with the pump bellows 7; the coupling plate 68 which is coupled
with the other end of the pump shaft 22; and the suction side and
discharge side check valves 24 and 26 which are attached to the
pump body 4 in the pump chamber 11. The coupling plates 68 of the
pump units 5 are coupled together, the suction valve ports 23 of
the suction side check valves 24 of the pump units 5 are
communicatingly connected to the suction port 2 of the pump body 4,
and the discharge valve ports 25 of the discharge side check valves
26 are communicatingly connected to the discharge port 3. The pump
bellows 7, the pump shafts 22, and the coupling plates 68 of the
pump units 5 are integrally reciprocated in the same direction by
air which is alternately supplied to the pump chambers 11 of the
pump units 5. The pump bellows 7 repeatedly extend and contract in
an alternate manner so that, when one of the pump units 5 sucks by
extension of the pump bellow 7 the transported liquid from the
suction port 2 of the pump body 4 into the pump chamber 11 via the
suction side check valve 24, the other pump unit 5 discharges by
contraction of the pump bellow 7 the transported liquid from the
discharge port 3 of the pump body 4 via the discharge side check
valve 26.
[0050] Also the bellows pump 67 of the third embodiment is
resinified in the same manner as the bellows pump 58 of the second
embodiment.
[0051] As apparent from the above description, each of the bellows
pumps 1, 58, 67 of the first to third embodiments comprises the
pump bellows 7 that axially extends and contracts, sucks the
transported liquid by extension of the pump bellows from the
suction port 2 of the pump body 4 into the pump bellows 7 via the
suction side check valve 24, and discharges the transported liquid
by contraction of the pump bellows from the discharge port 3 of the
pump body 4 via the discharge side check valve 26. As seen from the
corresponding figures of the bellows pumps 1, 58, 67, the pump
bellows 7 and the pump shaft 22, or the pump shaft 22 and the
piston 19 or the coupling plate 68, i.e., the three components of
the pump bellows 7, the pump shaft 22, and the piston 19 or the
coupling plate 68 which are integrally reciprocated are coupled
together by the same coupling structure (method). The coupling
structure will be described below.
[0052] First, the coupling structure of the pump bellows 7 and the
pump shaft 22 in each of the bellows pumps 1, 58, 67 will be
described. As enlargedly shown in FIGS. 2, 4, and 6, an external
thread 69 is formed on the outer face (the outer face on the side
of the pump bellows 7) of one end side of the pump shaft 22, so
that the pump shaft 22 has a bolt structure. By contrast, in the
bottomed cylindrical pump bellows 7, a bottomed cylindrical shaft
screwed portion 70 is projected from a center portion of the bottom
into the pump bellows 7 on the same axis X, an internal thread 71
which is to be screwed with the external thread 69 of the pump
shaft 22 is formed on the inner face of the shaft screwed portion
70, and a shaft joint is integrated with a center portion of the
pump bellows 7. According to the configuration, one end side of the
pump shaft 22 can be directly coupled with a center portion of the
pump bellows 7 by thread joining.
[0053] According to the coupling structure of the pump bellows 7
and the pump shaft 22, the pump shaft 22 is directly screwed into
the shaft screwed portion 70 disposed in the center portion of the
pump bellows 7, whereby the pump bellows 7 and the pump shaft 22
can be coupled and placed on the same axis X without using a flange
and plural bolts. In this way, fastening parts are eliminated.
Therefore, troubles due to loosening or slipping off of fastening
parts can be prevented from occurring in the bellows pumps 1, 58,
67. That is, uneven wearing can be prevented from occurring in the
sliding portion of the pump shaft 22, i.e., the periphery of the
center hole 21 of the cylinder head portion 15, whereby the life
period of the bellows pumps 1, 58, 67 can be prolonged, reduction
of the performance of the bellows pumps 1, 58, 67 due to increase
of the sliding resistance can be prevented from occurring, and the
performance of the bellows pumps 1, 58, 67 can be maintained for a
long term. Operation failures and damages of the bellows pumps 1,
58, 67 due to slipping off of a bolt are completely eliminated. The
axial length of the bellows pumps 1, 58, 67 can be shortened by at
least a dimension corresponding to that which is obtained by adding
together the thicknesses of a flange and the head of a bolt.
Therefore, compactification of the bellows pumps 1, 58, 67 can be
realized. Moreover, improvement of the productivity of the bellows
pumps 1, 58, 67, and reduction of the production cost can be
realized by decrease of the number of components, and reduction of
the number of assembly steps due to the decrease.
[0054] In the pump body 4, a circular recess 72 which has a
diameter that is slightly larger than the outer diameter of the
shaft screwed portion 70 of the pump bellows 7, and which has a
depth that is larger than the extension stroke of the pump bellows
7 is formed concentrically in a center portion of the pump body.
The shaft screwed portion 70 is formed so as to have a length at
which the tip end side of the portion is always (not only when the
pump bellows 7 contracts, but also when it extends) fitted into the
recess 72 of the pump body 4. The tip end side of the shaft screwed
portion 70 of the pump bellows 7 is always fitted into the recess
72 of the pump body 4.
[0055] According to the coupling structure of the pump bellows 7
and the pump shaft 22, compactification of the bellows pumps 1, 58,
67 can be realized while sufficiently ensuring the thread bonding
strength between the pump bellows 7 and the pump shaft 22. Since
the interior of the pump bellows 7, i.e., the center portion of the
pump chamber 11 is filled with the shaft screwed portion 70, the
total inner capacity of the pump bellows 7 (the capacity of the
whole pump chamber 11) can be reduced so that the capacity ratio of
the capacity of the accordion portion (the telescopic barrel
portion 10: the portion exerting the pump action) to the total
inner capacity of the pump bellows 7 (the capacity of the whole
pump chamber 11) is increased. Therefore, the bellows pumps 1, 58,
67 can quickly start in the startup time, the discharge pressure is
raised, and the performance of the bellows pumps 1, 58, 67 having
the internal liquid structure can be improved.
[0056] Next, the coupling structure of the pump shaft 22 and the
piston 19 or the coupling plate 68 in each of the bellows pumps 1,
58, 67 will be described. As enlargedly shown in FIGS. 2, 4, and 6,
a circular engagement head 73 having a diameter which is larger
than the diameter of the pump shaft 22 is integrally formed in
another end of the shaft (the end on the side of the piston 19, or
that on the side of the coupling plate 68). By contrast, a stepped
center hole 74 into which the other end of the pump shaft 22
including the engagement head 73 can be fitted is formed in the
piston 19 or the coupling plate 68. The center hole 74 is a stepped
hole which has a circular section shape, and in which the hole
diameter on one side (the side of the piston 19 or the coupling
plate 68 on the side of the cylinder head portion 15) whit respect
to a step face 75 is larger than that of the other side (the side
of the piston 19 or the coupling plate 68 opposite to the cylinder
head portion 15). The hole diameter of the small-diameter portion
76 is substantially equal to the outer diameter of the barrel
portion of the pump shaft 22, and the hole diameter of the
large-diameter portion 77 is substantially equal to the outer
diameter of the engagement head 73 of the pump shaft 22. An annular
sealing member which is used for filling a gap with respect to the
center hole 74, and which is made of an elastic material, such as
an O-ring 78 made of a fluororesin is attached to the pump shaft
22. The O-ring 78 is attached to a portion of the pump shaft 22
which is to be fitted into the small-diameter portion 76. According
to the configuration, the other end side of the pump shaft 22 can
be coupled with the center portion of the piston 19 or the coupling
plate 68 by means of fitting. Alternatively, the O-ring 78 may be
attached to the side of the center hole 74, i.e., the piston 19 or
the coupling plate 68.
[0057] According to the coupling structure of the pump shaft 22 and
the piston 19 or the coupling plate 68, the O-ring 78 is attached
to the portion of the pump shaft 22 which is to be fitted into the
center hole 74, or to the side of the hole 74, and fitted into the
center hole 74 of the piston 19 or the coupling plate 68 in the
contracting direction of the pump bellows 7, whereby the gap
between the pump shaft 22 and the center hole 74 is filled with the
O-ring 78, and the pump shaft 22 is radially positioned by the
O-ring 78. Therefore, the pump shaft 22 and the piston 19 or the
coupling plate 68 are not required to be fastened by bolts and
nuts, and can be easily coupled together and placed on the same
axis X. In this way, fastening parts are eliminated. Consequently,
troubles due to loosening or slipping off of fastening parts can be
prevented from occurring in the bellows pumps 1, 58, 67. That is,
uneven wearing can be prevented from occurring in the sliding
portion of the piston 19, i.e., the inner face of the second
cylinder section 17. Furthermore, the coupling plate 68 can be
prevented from obliquely applying a load to the pump shaft 22, and
uneven wearing can be prevented from occurring in the sliding
portion of the pump shaft 22, i.e., the periphery of the center
hole 21 the cylinder head portion 15. Therefore, the life period of
the bellows pumps 1, 58, 67 can be prolonged, reduction of the
performance of the bellows pumps 1, 58, 67 due to increase of the
sliding resistance can be prevented from occurring, and the
performance of the bellows pumps 1, 58, 67 can be maintained for a
long term. Operation failures and damages of the bellows pumps 1,
58, 67 due to slipping off of a bolt are completely eliminated.
Moreover, improvement of the productivity of the bellows pumps 1,
58, 67, and reduction of the production cost can be realized by
decrease of the number of components, and reduction of the number
of assembly steps due to the decrease. Since the center hole 74 of
the piston 19 or the coupling plate 68 is made as a stepped hole
into which the other end of the pump shaft 22 including the
engagement head 73 can be fitted, the axial length of the bellows
pumps 1, 58, 67 can be shortened by at least a dimension
corresponding to the thicknesses of the head of a bolt or a nut.
Therefore, also compactification of the bellows pumps 1, 58, 67 can
be simultaneously realized.
[0058] After the O-ring 78 is attached to the portion of the pump
shaft 22 which is to be fitted into the center hole 74, or to the
hole 74, the pump shaft 22 is passed through the center hole 74 of
the piston 19 or the coupling plate 68 and the center hole 21 of
the cylinder head portion 15 in the contracting direction of the
pump bellows 7, the tip end side of the pump shaft 22 is inserted
into the pump cylinder 14, and the inserted portion of the pump
shaft 22 is directly screwed into the shaft screwed portion 70 of
the pump bellows 7 until the tip end face of the pump shaft 22
butts against the bottom face of the shaft screwed portion 70,
whereby, as shown in the figures, the three components or the pump
bellows 7, the pump shaft 22, and the piston 19 or the coupling
plate 68 can be coupled together and placed on the same axis X
without using fastening parts.
[0059] In the double-bellows type bellows pumps 58, 67 of the
second and third embodiments, a shaft stopper 80 which, when the
pump bellows 7 contracts, prevents the pump shaft 22 from slipping
off from the piston 19 or the coupling plate 68 is detachably
attached to the outer side face of the piston 19 or the coupling
plate 68. The shaft stopper 80 is made of the same resin material
as the piston 19 or the coupling plate 68, and formed into a
bottomed cylindrical shape. By contrast, an annular groove 81 into
which the shaft stopper 80 can be fitted is concentrically formed
around the center hole 74 in the outer side face of the piston 19
or the coupling plate 68. Threads 82a, 82b which are screwed with
each other are formed in the outer peripheral face of the shaft
stopper 80 and that of the corresponding groove 81. The shaft
stopper 80 is thread-coupled with the groove 81 from the outer side
face of the piston 19 or the coupling plate 68, closes the opening
of the center hole 74 on the side of insertion of the pump shaft,
causes the inner bottom face of the shaft stopper 80 to be in close
contact with the engagement head 73 of the pump shaft 22,
pressingly holds the engagement head 73 of the pump shaft 22
between the inner bottom face of the shaft stopper 80 and the step
face 75 of the center hole 74, prevents the pump shaft 22 from
slipping off from the piston 19 or the coupling plate 68 when the
pump bellows 7 contracts, and transmits the extending operation of
one of the pump bellows 7 to the other pump bellows 7 to cause the
contracting operation. The shaft stopper is requested to prevent
the pump shaft 22 from slipping off from the piston 19 or the
coupling plate 68 when the pump bellows 7 contracts, and may have a
structure other than the above-described structure.
* * * * *