U.S. patent application number 10/479698 was filed with the patent office on 2004-09-30 for molten metal feeder.
Invention is credited to Funakoshi, Jun, Miura, Mitsushige, Nakagawa, Kenichi, Tsuchida, Jiro, Yamaguchi, Hiroshi.
Application Number | 20040191097 10/479698 |
Document ID | / |
Family ID | 32995552 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040191097 |
Kind Code |
A1 |
Nakagawa, Kenichi ; et
al. |
September 30, 2004 |
Molten metal feeder
Abstract
In order to feed molten metal to a casting mold with precision
while preventing introduction of metal oxide into a cylinder
casing, an entire valve box 19 is disposed below a liquid level of
the molten metal C inside a molten metal furnace D. A discharge
duct 23 is upwardly open at a lower end of a valve-element moving
space 24. An inlet duct 22 is open to the valve-element moving
space 24 at a position higher than the discharge duct 23. Around an
opening of the discharge duct 23 to the valve-element moving space
24, there is formed a lower receiving seat 29 in the form of a
ring. A valve element 21 includes a lower contact portion 31 which
comes into annular contact with the lower receiving seat 29 in
association with a lowering movement of the valve element 21. The
molten metal C inside the molten metal furnace D is introduced into
a cylinder casing 4 by moving the valve element 21 to an inlet
position where the lower contact portion 31 comes into the annular
contact with the lower receiving seat 29 thereby to block
communication between the discharge duct 23 and an inlet/outlet
duct 8.
Inventors: |
Nakagawa, Kenichi;
(Osaka-shi, JP) ; Tsuchida, Jiro; (Osaka-shi,
JP) ; Yamaguchi, Hiroshi; (Osaka-shi, JP) ;
Miura, Mitsushige; (Osaka-shi, JP) ; Funakoshi,
Jun; (Osaka-shi, JP) |
Correspondence
Address: |
Russel D Orkin
700 Koppers Building
436 Seventh Avenue
Pittsburgh
PA
15219-1818
US
|
Family ID: |
32995552 |
Appl. No.: |
10/479698 |
Filed: |
April 28, 2004 |
PCT Filed: |
June 3, 2002 |
PCT NO: |
PCT/JP02/05451 |
Current U.S.
Class: |
417/454 |
Current CPC
Class: |
B22D 39/00 20130101;
B22D 17/10 20130101; B22D 17/04 20130101; H01R 13/193 20130101;
H05K 7/1007 20130101; B22D 17/30 20130101 |
Class at
Publication: |
417/454 |
International
Class: |
F04B 039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2001 |
JP |
2001-170990 |
Jul 30, 2001 |
JP |
2001-229273 |
Apr 23, 2002 |
JP |
2001-121225 |
Claims
1. A feeding apparatus for molten metal, comprising: a molten metal
pump capable of introducing molten metal held in a molten metal
furnace into a cylinder casing through an inlet/outlet duct by
communicating the inlet-outlet duct for the molten metal with an
inside of the cylinder casing and moving a piston mounted within
the cylinder casing to one side and capable also of discharging the
molten metal in the cylinder casing through the inlet/outlet duct
by moving the piston to the other side; a feed duct for feeding the
molten metal discharged through the inlet/outlet duct to a casting
system; and a selector valve having a valve box defining, as
openings thereof open to a valve-element moving space thereof, an
inlet duct communicating with the molten metal furnace, a discharge
duct communicating with the feed duct and the inlet/outlet duct and
a valve element mounted therein and vertically movable between an
inlet position for establishing communication between the inlet
duct and the inlet/outlet duct and blocking communication between
the discharge duct and the inlet/outlet duct and an outlet position
for establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; characterized in that said
discharge duct is upwardly open at a lower end of said
valve-element moving space; said inlet duct is open to said
valve-element moving space at a position higher than said discharge
duct; around an opening of said discharge duct to said
valve-element moving space, there is formed a lower receiving seat
in the form of a ring; said valve element includes a lower contact
portion which comes into annular contact with said lower receiving
seat in association with a lowering movement of the valve element;
and the molten metal inside the molten metal furnace is introduced
into the cylinder casing by moving the valve element to the inlet
position where said lower contact portion comes into the annular
contact with said lower receiving seat thereby to block
communication between the discharge duct and the inlet/outlet duct;
said valve box forms a cylindrical valve-element attaching hole
capable of removably introducing the valve element therein; at an
upper inner peripheral face of said valve-element attaching hole, a
removable sleeve is fitted and fixed thereto; said inlet duct is
formed at an upper portion of the valve-element moving space, said
molten metal inside said cylinder casing is discharged to the feed
duct by moving said valve element to an outlet position where the
element comes into contact or sliding contact with said sleeve
thereby to block communication between said inlet duct and said
inlet/outlet duct.
2. The molten metal feeding apparatus as defined in claim 1,
characterized in that with an upward movement of said valve member,
said valve member comes into engagement within said sleeve, thereby
to block the communication between said inlet duct and said
inlet/outlet duct.
3. The molten metal feeding apparatus as defined in claim 1,
characterized in that an upper receiving seat is formed at a lower
end of said sleeve and said valve element includes an upper contact
portion which comes into annular contact with said upper receiving
seat in association with an upward movement of said valve
element.
4. A feeding apparatus for molten metal, comprising: a molten metal
pump capable of introducing molten metal held in a molten metal
furnace into a cylinder casing through an inlet/outlet duct by
communicating the inlet-outlet duct for the molten metal with an
inside of the cylinder casing and moving a piston mounted within
the cylinder casing to one side and capable also of discharging the
molten metal in the cylinder casing through the inlet/outlet duct
by moving the piston to the other side; a feed duct for feeding the
molten metal discharged through the inlet/outlet duct to a casting
system; and a selector valve having a valve box defining, as
openings open to a valve-element moving space thereof, an inlet
duct communicating with the molten metal furnace, a discharge duct
communicating with the feed duct and the inlet/outlet duct and a
valve element mounted therein and vertically movable between an
inlet position for establishing communication between the inlet
duct and the inlet/outlet duct and blocking communication between
the discharge duct and the inlet/outlet duct and an outlet position
for establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; characterized in that said
inlet duct is formed through said valve box to be open to the
valve-element moving space at a position higher than said discharge
duct; a base member including said cylinder casing forms an
engaging portion in which a feed-duct forming member forming said
feed duct is removably inserted and engaged from the above; said
discharge duct is communicated with the inside of said engaging
portion; said discharge duct is communicated with said feed duct
with said feed-duct forming member is engaged within said engaging
portion; said engaging portion defines, at a bottom thereof, a
communicating duct capable of communicating with said molten metal
furnace at a position lower than said discharge duct; and said
feed-duct forming member integrally includes a covering member
capable of closing said communicating duct in association with
engagement of said feed-duct forming member within said engaging
portion.
5. The molten metal feeding apparatus as defined in claim 4,
characterized in that said communicating duct is formed vertically
along the inserting/withdrawing direction of the feed-duct forming
member, and said covering member comes into engagement with the
communicating duct in association with the engagement of the
feed-duct forming member within the engaging portion.
6. A feeding apparatus for molten metal, comprising: a molten metal
pump capable of introducing molten metal held in a molten metal
furnace into a cylinder casing through an inlet/outlet duct by
communicating the inlet-outlet duct for the molten metal with an
inside of the cylinder casing and moving a piston mounted within
the cylinder casing to one side and capable also of discharging the
molten metal in the cylinder casing through the inlet/outlet duct
by moving the piston to the other side; a feed duct for feeding the
molten metal discharged through the inlet/outlet duct to a casting
system; and a selector valve having a valve box defining, as
openings open to a valve-element moving space thereof, an inlet
duct communicating with the molten metal furnace, a discharge duct
communicating with the feed duct and the inlet/outlet duct and a
valve element mounted therein and vertically movable between an
inlet position for establishing communication between the inlet
duct and the inlet/outlet duct and blocking communication between
the discharge duct and the inlet/outlet duct and an outlet position
for establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; characterized in that said
inlet duct is formed through said valve box to be open to the
valve-element moving space at a position higher than said discharge
duct; a base member including said cylinder casing forms an
engaging portion in which said valve box is removably inserted and
engaged from the above; said feed duct is communicated with the
inside of said engaging portion; said feed duct is communicated
with said discharge duct with said valve box is engaged within said
engaging portion; said engaging portion defines, at a bottom
thereof, a communicating duct capable of communicating with said
molten metal furnace at a position lower than said feed duct; and
said valve box integrally includes a covering member capable of
closing said communicating duct in association with engagement of
said valve box within said engaging portion.
7. The molten metal feeding apparatus as defined in claim 6,
characterized in that said communicating duct is formed vertically
along the inserting/drawing direction of said valve box; and said
covering member comes into engagement with said communicating duct
in association with the engagement of said valve box within said
engaging portion.
8. A feeding apparatus for molten metal, comprises: a molten metal
pump capable Of introducing molten metal held in a molten metal
furnace into a cylinder casing through an inlet/outlet duct by
communicating the inlet-outlet duct for the molten metal with an
inside of the cylinder casing and moving a piston mounted within
the cylinder casing to one side and capable also of discharging the
molten metal in the cylinder casing through the inlet/outlet duct
by moving the piston to the other side; a feed duct for feeding the
molten metal discharged through the inlet/outlet duct to a casting
system; and a selector valve having a valve box defining, as
openings open to a valve-element moving space thereof, an inlet
duct communicating with the molten metal furnace, a discharge duct
communicating with the feed duct and the inlet/outlet duct and a
valve element mounted therein and vertically movable between an
inlet position for establishing communication between the inlet
duct and the inlet/outlet duct and blocking communication between
the discharge duct and the inlet/outlet duct and an outlet position
for establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; characterized in that said
molten metal pump includes a cylinder-chamber forming hole formed
in said cylinder casing, a piston vertically movable within said
cylinder-chamber forming hole, and an operating rod for vertically
moving said piston; and said operating rod includes, upwardly of
said piston, a scraper for closing a gap between said operating rod
and said cylinder-chamber forming hole and slidable along
substantially entire periphery relative to said cylinder-chamber
forming hole in association with the vertical moving operation of
said operating rod.
9. A feeding apparatus for molten metal, comprises: a molten metal
pump capable of introducing molten metal held in a molten metal
furnace into a cylinder casing through an inlet/outlet duct by
communicating the inlet-outlet duct for the molten metal with an
inside of the cylinder casing and moving a piston mounted within
the cylinder casing to one side and capable also of discharging the
molten metal in the cylinder casing through the inlet/outlet duct
by moving the piston to the other side; a feed duct for feeding the
molten metal discharged through the inlet/outlet duct to a casting
system; and a selector valve having a valve box defining, as
openings open to a valve-element moving space thereof, an inlet
duct communicating with the molten metal furnace, a discharge duct
communicating with the feed duct and the inlet/outlet duct and a
valve element mounted therein and vertically movable between an
inlet position for establishing communication between the inlet
duct and the inlet/outlet duct and blocking communication between
the discharge duct and the inlet/outlet duct and an outlet position
for establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; characterized in that said
valve box includes an insertion hole having an upper end open to
the molten metal in the molten metal furnace; said selector valve
includes an operating rod capable of vertically moving operation;
said valve element includes a valve-element portion disposed to
come into sliding contact with an inner peripheral face of said
insertion hole; in association with a vertical movement of said
valve element within said insertion hole by said operating rod, the
duct for the molten metal can be switched over between an inlet
position for establishing communication between said inlet duct and
said inlet/outlet duct and blocking communication between said
discharge duct and said inlet/outlet duct by means of said
valve-element portion and an outlet position for establishing
communication between said discharge duct and said inlet/outlet
duct and blocking communication between said discharge duct and
said insertion hole by means of said valve-element portion and
blocking also communication between said inlet duct and said
inlet/outlet duct by means of said valve-element portion; and the
operating rod includes, upwardly of said valve-element portion, a
scraper for closing a gap between this operating rod and said
insertion hole and slidable along substantially entire periphery
relative to the inner peripheral face of the insertion hole in
association with the vertical moving operation of said operating
rod.
10. The molten metal feeding apparatus as defined in claim 9,
characterized in that said insertion hole comprises an upper
large-diameter insertion hole and a lower small-diameter insertion
hole connected together, the valve element includes a pair of upper
and lower valve-element portions provided to come into sliding
contact with an inner peripheral face of the small-diameter
insertion hole, and with a vertical movement of the valve element
within the insertion hole by the operating rod, the duct for the
molten metal is switched over between an inlet position for
establishing communication between the inlet duct and the
inlet/outlet duct and blocking communication between the discharge
duct and the inlet/outlet duct by means of the lower valve-element
portion and an outlet position for establishing communication
between the discharge duct and the inlet/outlet duct and blocking
communication between the discharge duct and the insertion hole by
means of the upper valve-element portion and blocking also
communication between the inlet duct and the inlet/outlet duct by
means of the lower valve-element portion.
11. The molten metal feeding apparatus as defined in any one of
claims 8-10, characterized in that when the operating rod has moved
to the upper end of its movable range, said scraper is moved to the
vicinity of the upper end of the insertion hole.
12. The molten metal feeding apparatus as defined in any one of
claims 8-10, characterized in that said scraper is formed by
non-withdrawably fitting, along the outer periphery of said
operating rod, a ceramic ring member formed like letter C by
cutting a peripheral portion thereof and then engaging this ring
member within said insertion hole with elastic radially inward
deformation of this ring member.
Description
TECHNICAL FIELD
[0001] The present invention relates to a feeding apparatus for
molten metal.
[0002] More particularly, the invention relates to a technique of
feeding molten meal in which there are provided a molten metal pump
capable of introducing molten metal held in a molten metal furnace
into a cylinder casing through an inlet/outlet duct by moving a
piston mounted within the cylinder casing to one side and capable
also of discharging the molten metal in the cylinder casing through
the inlet/outlet duct by moving the piston to the other side; a
feed duct capable of feeding the molten metal discharged through
the inlet/outlet duct to a casting system such as a casting device
or a casting mold; and a selector valve ha g a valve element
operable and movable between an inlet position for establishing
communication between the inlet/outlet duct and the molten metal
furnace while blocking communication between the inlet/outlet duct
and the feed duct and an outlet position for establishing
communication between the inlet/outlet duct and the feed duct while
blocking communication between the inlet/outlet duct and the molten
metal furnace, so that with an operation for moving the piston to
the one side with the valve element being located at the inlet
position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct.
BACKGROUND ART
[0003] Next, the conventional technique pertaining to the
above-described feeding apparatus for molten metal will be
described.
[0004] FIG. 15 shows a conventional molten metal feeding apparatus
including a molten metal pump 1 capable of introducing molten metal
C held inside a molten metal furnace D through an inlet/outlet duct
8 into a cylinder housing 4 by establishing communication between
the inlet/outlet duct 8 and the inside of the cylinder casing 4 and
moving upward a piston 5 mounted within the cylinder casing 4 and
capable also of discharging the molten metal C held inside the
cylinder casing 4 through the inlet/outlet duct 8 by moving
downward the piston 5, a driving unit 7 comprising e.g. a pneumatic
cylinder for driving and moving the piston 5, a feed duct 2 for
feeding the molten metal C discharged through the inlet/outlet duct
8 to a casting mold B1, and a selector valve 3 having a valve box
19 defining, as openings open to a valve-element moving space 24
thereof, an inlet duct 22 communicating with the molten metal
furnace D, a discharge duct 23 communicating with a feed duct 2 and
the inlet/outlet duct 8 communicating with the feed duct 2 and a
valve element 21 mounted therein and vertically movable between an
inlet position for establishing communication between the inlet
duct 22 and the inlet/outlet duct 8 and blocking communication
between the discharge duct 23 and the inlet/outlet duct 8 and an
outlet position for establishing communication between the
discharge duct 23 and the inlet/outlet duct 8 and blocking
communication between the inlet duct 22 and the inlet/outlet duct
8. Then, with an operation on a valve rod 20 by means of a
valve-rod operating tool 16 using e.g. a solenoid, as shown in FIG.
15(a), the valve element 21 is slid to the inlet position. Under
this condition, by moving the piston 5 upward, the molten metal C
held inside the molten metal furnace D is introduced into the
cylinder casing 4. Whereas, as shown in FIG. 15(b), by moving the
piston 5 downward with the valve element 21 being slid and retained
at the outlet position, the molten metal C held inside the cylinder
casing 4 is discharged to the feed duct 2.
[0005] And, in sliding the valve element 21 within the valve box
19, if high-temperature molten metal highly reactive to e.g. oxygen
is to be handled, even if there are provided sealants or the like
to sliding portions 100 between the valve element 21 and its valve
box 19, metal oxide or the like tends to be entrapped between the
sliding faces, so that there may develop a situation where the
valve element 21 cannot be moved smoothly. Hence, instead of
providing such sealant, for the sliding movement of the valve
element 21, there is provided a certain amount of clearance between
the sliding faces for resisting such entrapment of metal oxide or
the like.
[0006] For this reason, when the feeding operation of feeding the
molten metal C to the casing mold B1 is effected in repetition, as
shown in FIG. 15 (a), when the molten metal C inside the molten
metal furnace D is introduced into the cylinder casing 4 by
upwardly moving the piston 5 with sliding and retaining the valve
element 21 to and at its inlet position, it sometimes happens that
an amount of molten metal C remaining in the feed duct 2 may be
inadvertently introduced into the cylinder casing 4 via the
clearance of the sliding portions 100 or as shown in FIG. 15(b),
when the molten metal C held inside the cylinder casing 4 is
discharged to the feed duct 2 by downwardly moving the piston 5
with sliding and retaining the valve element 21 to and at its
outlet position, the molten metal C inside the cylinder casing 4
may be inadvertently discharged to the side of the molten metal
furnace D via the clearance of the sliding portions 100. In such
cases, it is not possible to feed to the casing mold B1 the molten
metal C by an amount corresponding to the movement stroke of the
piston 5, with high precision.
[0007] That is to say, when a plurality of feeding operations are
effected in repetition, the next cycle of feeding operation is
effected based on the assumption that a portion of the molten metal
C discharged by the previous cycle of feeding operation still
remains at a predetermined liquid level P within the feed duct 2.
Therefore, after an amount of molten metal C corresponding to the
movement stroke of the piston 5 has been fed to the casting mold
B1, it is required that a portion of the molten metal C discharged
by this previous feeding operation remain within the feed duct 2 at
the same liquid level P as that of the molten metal C remaining
after the previous feeding operation.
[0008] However, at the time of introduction of the molten metal C
illustrated in FIG. 15(a), if a portion of the molten metal C
remaining in the feed duct 2 is introduced into the cylinder casing
4 via the clearance between the sliding portions 100 of the valve
element 21 and of the valve box 19, this results in the liquid
level of the molten metal C remaining in the feed duct 2 becoming
lower than the predetermined liquid level P. In such case, in the
subsequent feeding operation, even if the molten metal C is
discharged to the feed duct 2 by the amount corresponding to the
movement stroke of the piston 5, the actual feeding amount to the
casting mold B1 will fall short by the amount corresponding to a
difference between these liquid levels. Further, at the time of
discharge of the molten metal C illustrated in FIG. 15(b), if a
portion of the molten metal C retained within the cylinder casing 4
is discharged to the side of the molten metal furnace D via the
clearance of the sliding portions 100, it becomes impossible to
discharge the molten metal C to the feed cut 2 by the amount
corresponding to the movement stroke of the piston 5, so that there
occurs shortage in the amount actually fed to the casting mold
B1.
[0009] Moreover, since the entire valve box 19 is disposed below
the liquid level of the molten metal C held inside the molten metal
furnace D, there is obtained an advantage of restricting the metal
oxide which may be entrapped between the sliding faces. However,
since the inlet duct 22 is formed at a lower portion of the valve
box 19, there is a disadvantage of any metal oxide accumulated at
the bottom of the molten metal furnace D tending to be introduced
into the cylinder housing 4.
[0010] The present invention has been made in view of the
above-described state of the art and its object is to enable
high-precision feeding of molten metal to a casting system such as
a casting mold or a casting device by an amount corresponding to a
movement stroke of the piston while preventing introduction of
metal oxide into the cylinder casing.
[0011] Also, if the inlet opening of the inlet duct is to be open
into the molten metal at a high position inside the molten metal
furnace so that molten metal with reduced possibility of admixing
of metal oxide therein may be introduced into the cylinder casing,
it is necessary to separately connect a duct for introduction of
molten metal to the inlet duct and to form the entrance of this
duct as the inlet opening at a high position inside the molten
metal furnace. As a result, there arises a disadvantage of
construction complexity.
[0012] And, if the duct for the introduction of molten metal is
connected separately to the inlet duct and the entrance of this
duct as the inlet opening is provided at a high position inside the
molten metal furnace, there arises another disadvantage that when
the feeding apparatus is removed out of the molten metal furnace
for the purpose of e.g. its maintenance, it is difficult to drain
any molten metal remaining within the valve box, the feed duct or
the like into the molten metal furnace.
[0013] The present invention has been made in view of the
above-described state of the art and its object is to enable a
simple construction to allow facilitation of draining of molten
metal remaining within the valve box, the feed duct or the like
into the molten metal furnace when the feeding apparatus is removed
out of the molten metal furnace, while allowing also introduction,
into the cylinder casing, of the molten metal with lower
possibility of admixture of metal oxide therein.
[0014] Further, the feeding apparatus can be alternatively
constructed as follows. Namely, in one such alternative
construction, there is provided a selector valve constructed as
follows. A valve element as an operated member and its operating
rod are coupled together and an insertion hole for allowing
vertically movable insertion of the valve element and the operating
rod is provided with an upper end thereof being open into the
molten metal in the molten metal furnace and with the lower portion
of this insertion hole forming a hole for allowing movement of the
valve element. Then, the valve element is inserted into the valve
element moving hole with the operating rod projecting from the
upper end of the insertion hole. Hence, the duct selector valve is
capable of switching over the duct for the molten metal by changing
its contacting condition relative to the inner face of the valve
element moving hole for the valve element in association with a
vertical moving operation of the operating rod. In anther
alternative construction, there is provided a molten metal pump
constructed as follows. A piston as an operated member and its
operating rod are connected together and an insertion hole for
allowing vertically movable insertion of the piston and the
operating rod is provided with an upper end thereof being open into
the molten metal in the molten metal furnace and with the lower
portion of this insertion hole forming a hole for allowing movement
of the piston. Then, the piston is inserted into the piston moving
hole with the operating rod projecting from the upper end of the
insertion hole. Thus the pump is capable of introducing/discharging
the molten metal in and out of the piston moving hole by changing
its contacting condition relative to the inner face of the piston
moving hole for the piston in association with a vertical moving
operation of the operating rod. In such cases, with the
above-described duct selector valve or the molten metal pump, the
operating rod is inserted into the insertion hole so as to form,
between the operating rod and the insertion hole, a continuous
clearance along the lower end of the operating rod and the upper
end of the insertion hole. Therefore, sludge such as metal oxide
generated adjacent the liquid surface of the molten metal of the
molten metal furnace tends to fall along the clearance between the
operating rod and the insertion hole and to enter the vicinity of
the operated member and get stuck to or accumulated on the inner
face of the insertion hole. Hence, there arises a disadvantage that
the contact condition of the operated member relative to the inner
face of the insertion hole can not be maintained at a desired state
for an extended period of time.
[0015] The present invention has been made in view of the
above-described state of the art and its object is to enable the
contact condition of the operated member relative to the inner face
of the insertion hole to be maintained at the desired state for an
extended period of time.
DISCLOSURE OF THE INVENTION
[0016] According the invention as defined in claim 1, a feeding
apparatus for molten metal, comprises: a molten metal pump capable
of introducing molten metal held in a molten metal furnace into a
cylinder casing through an inlet/outlet duct by communicating the
inlet/outlet duct for the molten metal with an inside of the
cylinder casing and moving a piston mounted within the cylinder
casing to one side and capable also of discharging the molten metal
in the cylinder casing through the inlet/outlet duct by moving the
piston to the other side; a feed duct for feeding the molten metal
discharged through the inlet/outlet duct to a casting system such
as a casting mold or a casting device; and a selector valve having
a valve box defining, as openings thereof open to a valve-element
moving space thereof, an inlet duct communicating with the molten
metal furnace, a discharge duct communicating with the feed duct
and the inlet/outlet duct and a valve element mounted therein and
vertically movable between an inlet position for establishing
communication between the inlet duct and the inlet/outlet duct and
blocking communication between the discharge duct and the
inlet/outlet duct and an outlet position for establishing
communication between the discharge duct and the inlet/outlet duct
and blocking communication between the inlet duct and the
inlet/outlet duct, so that with an operation for moving the piston
to the one side with the valve element being located at the inlet
position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; the apparatus being
characterized in that said discharge duct is upwardly open at a
lower end of said valve-element moving space; said inlet duct is
open to said valve-element moving space at a position higher than
said discharge duct; around an opening of said discharge duct to
said valve-element moving space, there is formed a lower receiving
seat in the form of a ring; said valve element includes a lower
contact portion which comes into annular contact with said lower
receiving seat in association with a lowering movement of the valve
element; and the molten metal inside the molten metal furnace is
introduced into the cylinder casing by moving the valve element to
the inlet position where said lower contact portion comes into the
annular contact with said lower receiving seat thereby to block
communication between the discharge duct and the inlet/outlet duct;
said valve box forms a cylindrical valve-element attaching hole
capable of removably introducing the valve element therein; at an
upper inner peripheral face of said valve-element attaching hole, a
removable sleeve is fitted and fixed thereto; said inlet duct is
formed at an upper portion of the valve-element moving space, said
molten metal inside said cylinder casing is discharged to the feed
duct by moving said valve element to an outlet position where the
element comes into contact or sliding contact with said sleeve
thereby to block communication between said inlet duct and said
inlet/outlet duct.
[0017] [Function and Effect]
[0018] Unlike the convention in which the valve element is slid to
the inlet position for blocking communication between the discharge
duct and the inlet/outlet duct, the valve box forms the discharge
duct to be upwardly open at a lower end of the valve-element moving
space. And, around this opening, there is formed an annular lower
receiving seat and this valve element forms a lower contact portion
which comes into annular contact with said lower receiving seat in
association with a lowering movement of the valve element; and the
molten metal inside the molten metal furnace is introduced into the
cylinder casing by moving the valve element to the inlet position
where the lower contact portion comes into the annular contact with
the lower receiving seat thereby to block communication between the
discharge duct and the inlet/outlet duct. With this, it is possible
to reliably block the communication between the discharge duct and
the inlet/outlet duct. As a result, when the molten metal retained
within the molten metal furnace is to be introduced into the
cylinder casing, it is possible to effectively prevent the molten
metal remaining in the feed duct from being inadvertently
introduced to the cylinder casing.
[0019] Further, the entire valve box is disposed below the liquid
level of the molten metal held within the molten metal furnace so
as to avoid oxidation of the molten metal introduced into the valve
box and the discharge duct is upwardly open at the lower end of the
valve-element moving space and the inlet duct is open to the
valve-element moving space at a position higher than the discharge
duct, so as to restrict inadvertent introduction of any metal oxide
accumulated at the bottom of the molten metal furnace into the
cylinder casing.
[0020] Therefore, when the molten metal held in the molten metal
furnace is to be introduced into the cylinder casing, metal oxide
accumulated at the bottom of the molten metal furnace will hardly
enter the cylinder casing and also since the inadvertent
introduction of any molten metal remaining in the feed duct to the
cylinder case is effectively restricted, it is possible to feed,
with high precision, an amount of molten metal corresponding to the
movement stroke of the piston to the casting system such as a
casting mold, while avoiding introduction of metal oxide into the
cylinder casing.
[0021] Further, said valve box forms a cylindrical valve-element
attaching hole capable of removably introducing the valve element
therein; at an upper inner peripheral face of said valve-element
attaching hole, a removable sleeve is fitted and fixed thereto;
said inlet duct is formed at an upper portion of the valve-element
moving space, said molten metal inside said cylinder casing is
discharged to the feed duct by moving said valve element to an
outlet position where the element comes into contact or sliding
contact with said sleeve thereby to block communication between
said inlet duct and said inlet/outlet duct. Therefore, it is
possible to reliably block communication between the inlet duct and
the inlet/outlet duct. And, when the molten metal inside the
cylinder casing is to be discharged to the feed duct, it is
possible to effectively prevent inadvertent discharge of the molten
metal in the cylinder casing to the side of the molten metal
furnace.
[0022] According to the invention as defined in claim 2, with an
upward movement of said valve member, said valve member comes into
engagement within said sleeve, thereby to block the communication
between said inlet duct and said inlet/outlet duct.
[0023] [Function and Effect]
[0024] Unlike the convention in which the valve element is slid to
the outlet position for blocking communication between the inlet
duct and the inlet/outlet duct, with an upward movement of said
valve element, said valve element comes into engagement within said
sleeve, thereby to block the communication between said inlet duct
and said inlet/outlet duct. With this, it is possible to reliably
block the communication between the inlet duct and the inlet/outlet
duct. As a result, when the molten metal retained within the
cylinder casing is to be discharged to the feed duct, it is
possible to effectively prevent the molten metal remaining in the
cylinder casing from being inadvertently discharged to the side of
the molten metal furnace.
[0025] Therefore, when the molten metal held in the cylinder casing
is to be discharged to the feed duct, the molten metal held in the
cylinder casing will hardly be discharged to the side of the molten
metal furnace. As a result, it is possible to feed, with even
higher precision, an amount of molten metal corresponding to the
movement stroke of the piston.
[0026] According to the invention as defined in claim 3, an upper
receiving seat is formed at a lower end of said sleeve and said
valve element includes an upper contact portion which comes into
annular contact with said upper receiving seat in association with
an upward movement of said valve element.
[0027] [Function and Effect]
[0028] Unlike the convention in which the valve element is slid to
the outlet position for blocking communication between the inlet
duct and the inlet/outlet duct, an upper receiving seat is formed
at a lower end of said sleeve and said valve element includes an
upper contact portion which comes into annular contact with said
upper receiving seat in association with an upward movement of said
valve element. And, by moving the valve element to the outlet
position where the upper contact portion comes into the annular
contact with the upper receiving seat to block the communication
between the inlet duct and the inlet/outlet duct and with a moving
operation of the piston to the other side, the molten metal held
inside the cylinder casing is discharged to the feed duct.
Therefore, it is possible to reliably block the communication
between the inlet duct and the inlet/outlet duct and when the
molten metal retained within the cylinder casing is to be
discharged to the feed duct, it is possible to effectively prevent
the molten metal remaining in the cylinder casing from being
inadvertently discharged to the side of the molten metal
furnace.
[0029] Therefore, since the molten metal in the cylinder casing is
hardly discharged to the side of the molten metal furnace, it is
possible to feed the molten metal to the casting mold with even
higher precision by the amount corresponding to the moving stroke
of the piston.
[0030] According the invention as defined in claim 4, a feeding
apparatus for molten metal, comprises: a molten metal pump capable
of introducing molten metal held in a molten metal furnace into a
cylinder casing through an inlet/outlet duct by communicating the
inlet-outlet duct for the molten metal with an inside of the
cylinder casing and moving a piston mounted within the cylinder
casing to one side and capable also of discharging the molten metal
in the cylinder casing through the inlet/outlet duct by moving the
piston to the other side; a feed duct for feeding the molten metal
discharged through the inlet/outlet duct to a casting system such
as a casting device; and a selector valve having a valve box
defining, as openings open to a valve-element moving space thereof,
an inlet duct communicating with the molten metal furnace, a
discharge duct communicating with the feed duct and the
inlet/outlet duct and a valve element mounted therein and
vertically movable between an inlet position for establishing
communication between the inlet duct and the inlet/outlet duct and
blocking communication between the discharge duct and the
inlet/outlet duct and an outlet position for establishing
communication between the discharge duct and the inlet/outlet duct
and blocking communication between the inlet duct and the
inlet/outlet duct, so that with an operation for moving the piston
to the one side with the valve element being located at the inlet
position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; the apparatus being
characterized in that said inlet duct is formed through said valve
box to be open to the valve-element moving space at a position
higher than said discharge duct; a base member including said
cylinder casing forms an engaging portion in which a feed-duct
forming member forming said feed duct is removably inserted and
engaged from the above; said discharge duct is communicated with
the inside of said engaging portion; said discharge duct is
communicated with said feed duct with said feed-duct forming member
is engaged within said engaging portion; said engaging portion
defines, at a bottom thereof, a communicating duct capable of
communicating with said molten metal furnace at a position lower
than said discharge duct; and said feed-duct forming member
integrally includes a covering member capable of closing said
communicating duct in association with engagement of said feed-duct
forming member within said engaging portion.
[0031] [Function and Effect]
[0032] Since the inlet duct is formed through said valve box to be
open to the valve-element moving space at a position higher than
said discharge duct, unlike the convention, it is not necessary to
connect separately a duct for introducing molten metal to the inlet
duct and the inlet opening of the inlet duct may be disposed to be
open into the molten metal at a high position within the molten
metal furnace.
[0033] And, a base member including said cylinder casing forms an
engaging portion in which a feed-duct forming member forming said
feed duct is removably inserted and engaged from the above, said
discharge duct is communicated with the inside of said engaging
portion and said discharge duct is communicated with said feed duct
with said feed-duct forming member is engaged within said engaging
portion. Hence, when the feeding apparatus is drawn up out of the
molten metal furnace, by pulling up the feed-duct forming member
out of the engaging portion, any molten metal present within the
feed duct formed in this feed-duct forming member can be discharged
into the molten metal furnace. And, with establishment of
communication between the inside of the valve box and the inside of
the molten metal furnace through the discharge duct, the molten
metal present within the valve box can be discharged into the
molten metal furnace through the discharge duct.
[0034] Further, said engaging portion defines, at a bottom thereof,
a communicating duct capable of communicating with said molten
metal furnace at a position lower than said discharge duct; and
said feed-duct forming member integrally includes a covering member
capable of closing said communicating duct in association with
engagement of said feed-duct forming member within said engaging
portion. Hence, by pulling up the feed-duct forming member out of
the engaging portion, the closure of the communicating duct is
released to establish communication between the bottom of the
engaging portion with the molten metal furnace via the
communicating duct. Thus, when the cylinder case is pulled up out
of the molten metal furnace, the risk of any molten metal remaining
in the engaging portion is reduced advantageously.
[0035] Therefore, by means of the simple construction wherein the
inlet duct is formed though the valve box to be open to the
valve-element moving space at a position higher than the discharge
duct, molten metal with lower possibility of presence of metal
oxide mixed therein can be introduced into the cylinder casing. At
the same time, when the feeding apparatus is removed out of the
molten metal furnace, any molten metal present within the valve box
or the feed duct can be easily discharged into the molten metal
furnace.
[0036] According to the invention as defined in claim 5, said
communicating duct is formed vertically along the
inserting/withdrawing direction of the feed-duct forming member,
and said covering member comes into engagement with the
communicating duct in association with the engagement of the
feed-duct forming member within the engaging portion.
[0037] [Function and Effect]
[0038] With the operation of engaging the feed-duct forming member
in the engaging portion from the above, the covering member too
comes into engagement with the communicating duct thereby to close
its opening. Whereas, with an operation of drawing up the feed-duct
forming member out of the engaging portion, the covering member too
becomes removed from the communicating duct, thereby to release its
closure.
[0039] Therefore, with the inserting/drawing operation of the
feed-duct forming member relative to the engaging portion to one
side in the vertical direction, the communicating duct can be
closed or its closure can be released.
[0040] According the invention as defined in claim 6, a feeding
apparatus for molten metal, comprises: a molten metal pump capable
of introducing molten metal held in a molten metal furnace into a
cylinder casing through an inlet/outlet duct by communicating the
inlet-outlet duct for the molten metal with an inside of the
cylinder casing and moving a piston mounted within the cylinder
casing to one side and capable also of discharging the molten metal
in the cylinder casing through the inlet/outlet duct by moving the
piston to the other side; a feed duct for feeding the molten metal
discharged through the inlet/outlet duct to a casting system such
as a casting device; and a selector valve having a valve box
defining, as openings open to a valve-element moving space thereof,
an inlet duct communicating with the molten metal furnace, a
discharge duct communicating with the feed duct and the
inlet/outlet duct and a valve element mounted therein and
vertically movable between an inlet position for establishing
communication between the inlet duct and the inlet/outlet duct and
blocking communication between the discharge duct and the
inlet/outlet duct and an outlet position for establishing
communication between the discharge duct and the inlet/outlet duct
and blocking communication between the inlet duct and the
inlet/outlet duct, so that with an operation for moving the piston
to the one side with the valve element being located at the inlet
position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; the apparatus being
characterized in that said inlet duct is formed through said valve
box to be open to the valve-element moving space at a position
higher than said discharge duct; a base member including said
cylinder casing forms an engaging portion in which said valve box
is removably inserted and engaged from the above; said feed duct is
communicated with the inside of said engaging portion; said feed
duct is communicated with said discharge duct with said valve box
is engaged within said engaging portion; said engaging portion
defines, at a bottom thereof, a communicating duct capable of
communicating with said molten metal furnace at a position lower
than said feed duct; and said valve box integrally includes a
covering member capable of closing said communicating duct in
association with engagement of said valve box within said engaging
portion.
[0041] [Function and Effect]
[0042] Since the inlet duct is formed through said valve box to be
open to the valve-element moving space at a position higher than
said discharge duct, unlike the convention, it is not necessary to
connect separately a duct for introducing molten metal to the inlet
duct and the inlet opening of the inlet duct may be disposed to be
open into the molten metal at a high position within the molten
metal furnace.
[0043] And, a base member including said cylinder casing forms an
engaging portion in which the valve box is removably inserted and
engaged from the above, said feed duct is communicated with the
inside of said engaging portion and said feed duct is communicated
with the inner side of the engaging portion, and the feed duct is
communicated with said discharge duct when said valve box is
engaged within said engaging portion. Hence, when the feeding
apparatus is drawn up out of the molten metal furnace, by pulling
up the valve box out of the engaging portion, any molten metal
present within this valve box can be discharged into the molten
metal furnace through the discharge duct. And, with establishment
of communication between the feed duct and the inside of the molten
metal furnace at the engaging portion, the molten metal present
within the feed duct can be discharged into the molten metal
furnaces
[0044] Further, said engaging portion defines therethrough, at a
bottom thereof, a communicating duct capable of communicating with
said molten metal furnace at a position lower than said feed duct;
and said valve box integrally includes a covering member capable of
closing said communicating duct in association with engagement of
said valve box within said engaging portion. Hence, by pulling up
the valve box out of the engaging portion, the closure of the
communicating duct is released to establish communication between
the bottom of the engaging portion with the molten metal furnace
via the communicating duct. Thus, when the cylinder casing is
pulled up put of the molten metal furnace, the risk of any molten
metal remaining in the engaging portion is reduced
advantageously.
[0045] Therefore, by means of the simple construction wherein the
inlet duct is formed though the valve box to be open to the
valve-element moving space at a position higher than the discharge
duct, molten metal with lower possibility of presence of metal
oxide mixed therein can be introduced into the cylinder casing. At
the same time, when the feeding apparatus is removed out of the
molten metal furnace, any molten metal present within the valve box
or the feed duct can be easily discharged into the molten metal
furnace.
[0046] According to the invention as defined in claim 7, said
communicating duct is formed vertically along the inserting/drawing
direction of said valve box; and said covering member comes into
engagement with said communicating duct in association with the
engagement of said valve box within said engaging portion.
[0047] [Function and Effect]
[0048] In association with the engaging operation of the valve box
within the engaging portion from the above, the covering member too
comes into engagement with the communicating duct. Whereas, in
association with an upward drawing operation of the valve box out
of the engaging portion, the covering member too becomes disengaged
from the communicating duct, thereby to release its closure.
[0049] Therefore, with the simple operation of inserting/drawing
the valve box in one vertical direction, the communicating duct can
be closed or its closure can be released.
[0050] According to the invention as defined in claim 8, a feeding
apparatus for molten metal, comprises: a molten metal pump capable
of introducing molten metal held in a molten metal furnace into a
cylinder casing through an inlet/outlet duct by communicating the
inlet-outlet duct for the molten metal with an inside of the
cylinder casing and moving a piston mounted within the cylinder
casing to one side and capable also of discharging the molten metal
in the cylinder casing through the inlet/outlet duct by moving the
piston to the other side; a feed duct for feeding the molten metal
discharged through the inlet/outlet duct to a casting system; and a
selector valve having a valve box defining, as openings open to a
valve-element moving space thereof, an inlet duct communicating
with the molten metal furnace, a discharge duct communicating with
the feed duct and the inlet/outlet duct and a valve element mounted
therein and vertically movable between an inlet position for
establishing communication between the inlet duct and the
inlet/outlet duct and blocking communication between the discharge
duct and the inlet/outlet duct and an outlet position for
establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; the apparatus being
characterized in that said molten metal pump includes a
cylinder-chamber forming hole formed in said cylinder casing, a
piston vertically movable within said cylinder-chamber forming
hole, and an operating rod for vertically moving said piston; and
said operating rod includes, upwardly of said piston, a scraper for
closing a gap between said operating rod and said cylinder-chamber
forming hole and slidable along substantially entire periphery
relative to said cylinder-chamber forming hole in association with
the vertical moving operation of said operating rod.
[0051] [Function and Effect]
[0052] Since the operating rod includes, upwardly of said piston, a
scraper for closing a gap between this operating rod and said
cylinder-chamber forming hole, the condition in which the contact
position of the piston relative to the inner face of the piston
moving hole can be varied to a desired contact position, that is,
the condition in which the piston can be slid relative to the inner
face of the piston moving hole by a desired stroke, can be
maintained for an extended period of time and the molten metal can
be fed and discharged in and out of the piston moving hole with
high precision.
[0053] According to the invention as defined in claim 9, a feeding
apparatus for molten metal, comprises: a molten metal pump capable
of introducing molten metal held in a molten metal furnace into a
cylinder casing through an inlet/outlet duct by communicating the
inlet-outlet duct for the molten metal with an inside of the
cylinder casing and moving a piston mounted within the cylinder
casing to one side and capable also of discharging the molten metal
in the cylinder casing through the inlet/outlet duct by moving the
piston to the other side; a feed duct for feeding the molten metal
discharged through the inlet/outlet duct to a casting system; and a
selector valve having a valve box defining, as openings open to a
valve-element moving space thereof, an inlet duct communicating
with the molten metal furnace, a discharge duct communicating with
the feed duct and the inlet/outlet duct and a valve element mounted
therein and vertically movable between an inlet position for
establishing communication between the inlet duct and the
inlet/outlet duct and blocking communication between the discharge
duct and the inlet/outlet duct and an outlet position for
establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the inlet duct
and the inlet/outlet duct, so that with an operation for moving the
piston to the one side with the valve element being located at the
inlet position, the molten metal in the molten metal furnace is
introduced into the cylinder casing whereas with an operation for
moving the piston to the other side with the valve element being
located at the outlet position, the molten metal in the cylinder
casing is discharged to the feed duct; the apparatus being
characterized in that said valve box includes an insertion hole
having an upper end open to the molten metal in the molten metal
furnace; said selector valve includes an operating rod capable of
vertically moving operation; said valve element includes a
valve-element portion disposed to come into sliding contact with an
inner peripheral face of said insertion hole; in association with a
vertical movement of said valve element within said insertion hole
by said operating rod, the duct for the molten metal can be
switched over between an inlet position for establishing
communication between said inlet duct and said inlet/outlet duct
and blocking communication between said discharge duct and said
inlet/outlet duct by means of said valve-element portion and an
outlet position for establishing communication between said
discharge duct and said inlet/outlet duct and blocking
communication between said discharge duct and said insertion hole
by means of said valve-element portion and blocking also
communication between said inlet duct and said inlet/outlet duct by
means of said valve-element portion; and the operating rod
includes, upwardly of said valve-element portion, a scraper for
closing a gap between this operating rod and said insertion hole
and slidable along substantially entire periphery relative to the
inner peripheral face of the insertion hole in association with the
vertical moving operation of said operating rod.
[0054] [Function and Effect]
[0055] Since the operating rod includes, upwardly of said
valve-element portion, a scraper for closing a gap between this
operating rod and said insertion hole, sludge such as metal oxide
or the like generated in the vicinity of the liquid surface of the
molten metal in the molten metal furnace will hardly enter the
vicinity of the operated member. Further, since this scraper is
slidable along substantially entire periphery relative to the inner
peripheral face of the insertion hole in association with the
vertical moving operation of said operating rod, even if the sludge
becomes entrapped in the gap between the operating rod and the
insertion hole and adheres to the inner peripheral face of the
insertion hole, this sludge can be scraped off. So, the contact
condition of the operated member relative to the inner face of the
insertion hole can be maintained as desired for an extended period
of time.
[0056] According to the invention as defined in claim 10, said
insertion hole comprises an upper large-diameter insertion hole and
a lower small-diameter insertion hole connected together, the valve
element includes a pair of upper and lower valve-element portions
provided to come into sliding contact with an inner peripheral face
of the small-diameter insertion hole, and with a vertical movement
of the valve element within the insertion hole by the operating
rod, the duct for the molten metal is switched over between an
inlet position for establishing communication between the inlet
duct and the inlet/outlet duct and blocking communication between
the discharge duct and the inlet/outlet duct by means of the lower
valve-element portion and an outlet position for establishing
communication between the discharge duct and the inlet/outlet duct
and blocking communication between the discharge duct and the
insertion hole by means of the upper valve-element portion and
blocking also communication between the inlet duct and the
inlet/outlet duct by means of the lower valve-element portion.
[0057] [Function and Effect]
[0058] By vertically moving the valve element within the insertion
hole thereby to change its contact condition relative to the
insertion hole, the duct for the molten metal can be switched over
between the condition (to be referred to as "inlet position"
hereinafter) for establishing communication between the inlet duct
and the inlet/outlet duct and blocking communication between the
discharge duct and the inlet/outlet duct and the further condition
(to be referred to as "outlet position" hereinafter) for
establishing communication between the discharge duct and the
inlet/outlet duct and blocking communication between the discharge
duct and the large-diameter insertion hole and blocking also
communication between the inlet duct and the inlet/outlet duct.
[0059] According to the invention as defined in claim 11, when the
operating rod has moved to the upper end of its movable range, said
scraper is moved to the vicinity of the upper end of the insertion
hole.
[0060] [Function and Effect]
[0061] When the operated member has moved to the upper end of its
movable range, the scraper is moved to the vicinity of the upper
end of the insertion hole. Hence, the sludge scrapped off by the
scraper can be positively returned into the molten metal held in
the molten metal furnace. As a result, the contact condition of the
operated member relative to the inner face of the insertion hole
can be maintained as desired for an extended period of time.
[0062] According to the invention as defined in claim 12, said
scraper is formed by non-withdrawably fitting, along the outer
periphery of said operating rod, a ceramic ring member formed like
letter C by cutting a peripheral portion thereof and then engaging
this ring member within said insertion hole with elastic radially
inward deformation of this ring member.
[0063] [Function and Effect]
[0064] A ceramic ring member formed like letter C by cutting a
peripheral portion thereof is engaged within said insertion hole
with elastic radially inward deformation of this ring member.
Hence, the ring member can be in pressed contact with the inner
peripheral face of the insertion hole by means of the elastic
resilience thereof. As a result, by reducing the gap between the
ring member and the inner peripheral face of the insertion hole,
intrusion of sludge to the vicinity of the operated member can be
prevented in an efficient manner and also the sludge can be scraped
off efficiently.
[0065] Further, since the ring member is formed of ceramics, there
hardly occurs such phenomenon as "heat-sticking" or "biting"
between the ring member and the inner peripheral face of the
insertion hole due to mutual sliding therebetween. As a result,
with the pressed-contact between the ring member and the inner
peripheral face of the insertion hole by means of the elastic
resilience of the former, sludge can be scraped off in an efficient
manner for an extended period of time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] FIG. 1 is a side view in partial section of a feeding
apparatus for molten metal,
[0067] FIGS. 2(a) and (b) are side views in partial section showing
principal portions,
[0068] FIG. 3(a) is a perspective view of the principal
portions,
[0069] FIG. 3(b) is a vertical section showing the principal
portions,
[0070] FIGS. 4(a) and (b) are side views in partial sections of
principal portions showing a second embodiment,
[0071] FIGS. 5(a) and (b) are side views in partial sections of
principal portions showing a third embodiment,
[0072] FIGS. 6(a) and (b) are side views in partial sections of
principal portions showing a fourth embodiment,
[0073] FIG. 7 is a section of the principal portions of the fourth
embodiment,
[0074] FIG. 8 is a perspective view of the principal portions of
the fourth embodiment,
[0075] FIG. 9 is a section of the principal portions of the fourth
embodiment,
[0076] FIG. 10(a) is a perspective view of principal portions
showing a sixth embodiment,
[0077] FIG. 10(b) is a section view of the principal portions
showing the sixth embodiment,
[0078] FIG. 11 is a side view in partial section of principal
portions showing a seventh embodiment,
[0079] FIG. 12 is a side view in partial section of the principal
portions showing the seventh embodiment,
[0080] FIG. 13 is a perspective view of principal portions showing
an eighth embodiment,
[0081] FIGS. 14(a) and (b) are side views in partial section of
principal portions showing a ninth embodiment, and
[0082] FIGS. 15(a) and (b) are side views in partial sections
showing the prior art.
BEST MODE OF EMBODYING THE INVENTION
[0083] Next, the present invention will be described by way of
embodiments thereof with reference to the accompanying drawings.
Incidentally, in the drawings, elements shown with like references
denote like elements.
[0084] [First Embodiment]
[0085] FIG. 1 shows a feeding apparatus A for feeding molten metal
C of magnesium alloy as an example of molten metal to a casting
mold B1 of a casting device B. The apparatus includes a molten
metal pump 1, a feed duct 2 for feeding the molten metal C to the
casting mold B1 and a selector valve 3 for switching over ducts
between a condition capable of drawing the molten metal C held
within a molten metal furnace D into the molten metal pump 1 and a
further condition capable of discharging the molten metal C
introduced into the molten metal pump 1 to the feed duct 2, so that
the apparatus can feed the molten metal C discharged from the
molten metal pump 1 to the casting device B1 via the feed duct
2.
[0086] The molten metal pump 1 includes a cylinder casing 4 formed
of ceramics (silicon nitride), a piston 5 formed of ceramics
(silicon nitride) and vertically movable in reciprocation within
the cylinder casing 4 and a piston driving pneumatic cylinder 7 for
vertically reciprocating a piston rod 6 formed integrally with the
piston 5. In operation, as an inlet/outlet duct 8 for the molten
metal C is communicated with a vicinity of the bottom inside the
cylinder casing 4 and the piston 5 is moved upward, the molten
metal C held within a molten metal furnace D can be introduced via
the inlet/outlet duct 8 into the cylinder casing 4 and as the
piston 5 is moved downward, the molten metal C held within the
cylinder casing 4 can be discharged via the inlet/outlet duct
8.
[0087] Referring to the cylinder casing 4, a cylinder chamber 12 is
formed by closing a lower opening of a cylinder-chamber forming
through hole 10 defined in a casing body 9 formed of ceramics by
means of a cylinder plug 11 formed of ceramics. A base plate 14
secured to a furnace lid 13 of the molten metal furnace D is
connected with an outer periphery of the casing body 9 by mans of a
connecting arm 15 formed of ceramics (silicon nitride), and the
cylinder casing 4 is fixed so that this entire cylinder casing 4
may be submerged within the molten metal C at a position lower than
a vertically movable range of the liquid level of the molten metal
C within the molten metal furnace D. Further, a support table 17
for supporting the piston driving pneumatic cylinder 7 and a
valve-operating pneumatic cylinder 16 is secured to the base plate
14 by a mainstay 18.
[0088] Referring to the selector valve 3, as shown also in FIG. 2,
the casing body 9 forms a valve box 19 and the entire valve box 19
is disposed downwardly of a liquid level lower than the liquid
level vertically movable range of the molten metal C held within
the molten metal furnace D. Further, a valve element 21 formed of
ceramics (silicon nitride) forming a valve rod 20 integrally
therewith is mounted to this valve box 19 to be vertically movable
relative thereto. An inlet duct 22 communicating with the molten
metal furnace D, a discharge duct 23 communicating with the feed
duct 2 and the inlet/outlet duct 8 are formed to be open to a
valve-element moving space 24.
[0089] Referring to the valve-element moving space 24, as shown in
FIG. 2, a cylindrical valve-element attaching hole 25 into and from
which the valve element 21 can be inserted and withdrawn is formed
in the casing body 9 and a sleeve 26 is fitted and fixed within an
upper inner peripheral face of this valve-element attaching hole 25
and forming a valve-element attaching hole portion lower than the
sleeve 26.
[0090] The discharge duct 23 is formed to be upwardly open at the
lower end of the valve-element moving space 24 and an inlet through
hole 27 extending from the casing body 9 and the sleeve 26 is
formed. The inlet duct 22 downwardly open at the upper end of the
valve-element moving space 24 located at a higher position than the
discharge duct 23 is formed by the inlet through hole 27 and the
inner side of the sleeve 26 and the inlet opening of the inlet duct
22 is open to the molten metal C held within the molten metal
furnace D. Further, the valve rod 20 includes a covering member 28
slidable relative to the inner face of the sleeve 26 so as to close
the gap between the valve rod 20 and the sleeve 26.
[0091] The discharge duct 23 is formed in a discharge-duct forming
member (an example of base member) 33 formed of ceramics (silicon
nitride) and bolt-fixed to the casing body 9 and is open to the
bottom of the valve-element moving space 24. To this discharge-duct
forming member 33, a cylindrical feed pipe (an example of a
feed-duct forming member) 34 formed of ceramics (silicon nitride)
is connected to communicate the feed duct 2 to the discharge duct
23.
[0092] Around the opening of the discharge duct 23 to the
valve-element moving space 24, there is formed an annular upwardly
oriented lower receiving seat 29. And, around the opening of the
inlet duct 22 to the valve-element moving space 24, that is, at the
bottom face of the sleeve 26, there is formed an annular downwardly
oriented upper receiving seat 30. Whereas, the valve element 21
includes a lower contact portion 31 which comes into annular
contact with the lower receiving seat 29 in association with a
lowering movement of the valve element 21 and an upper contact
portion 32 which comes into annular contact with the upper
receiving seat 30 in association with an upward movement of the
valve element 21.
[0093] In operation, with an expanding or contacting operation of
the valve-operating pneumatic cylinder 16, the valve element 21 is
vertically movable between an inlet position in which the upper
contact portion 32 departs from the upper receiving seat 30 to
establish communication between the inlet duct 22 and the
inlet/outlet duct 23 and also the lower contact portion 31 comes
into the annular contact with the lower receiving seat 29 thereby
to block communication between the discharge duct 23 and the
inlet/outlet duct 8 as shown in FIG. 2(a) and an outlet position in
which the lower contact portion 31 departs from the lower receiving
seat 29 thereby to establish communication between the discharge
duct 23 and the inlet/outlet duct 8 and also the upper contact
portion 32 comes into the annular contact with the upper receiving
seat 30 thereby to block communication between the inlet duct 22
and the inlet/outlet duct 8 as shown in FIG. 2(b). Then, as shown
in FIG. 2(a), by operating the piston 5 upward with the valve
element 21 being shifted to the inlet position, the molten metal C
held within the molten metal furnace D is drawn into the cylinder
casing 4 via the inlet duct 22 and the inlet/outlet duct 8.
Whereas, as shown in FIG. 2(b), by operating the piston 5 downward
with the valve element 21 being shifted to the outlet position, the
molten metal C held within the cylinder casing 4 is discharged to
the feed duct 2 via the inlet/outlet duct 8 and the discharge duct
23 to the feed duct 2 so that the molten metal can be fed to the
casting mold B1.
[0094] As shown in FIG. 3, the discharge-duct forming member 33
forms an engaging hole (an example of engaging portion) 36 having a
circular shape in its plan view into which a feed pipe 34 is
removable inserted from the above and fixed in position to
establish communication between the discharge duct 33 with the
inside of the engaging hole 36 and this engaging hole 36 is formed
vertically through the feed pipe 34 along its inserting/withdrawing
direction. At the bottom of this engaging portion 36, there is
formed a communicating duct 37 capable of communicating with the
molten metal furnace D at a position lower than the discharge duct
23.
[0095] The feed pipe 34 integrally forms a pipe-end closing member
38 formed of ceramics (silicon nitride) for closing the bottom end
of this pipe and a through hole 39 is formed in a pipe wall
adjacent the pipe-end closing member 38. So that, as the feed pipe
34 is fitted within the engaging hole 36, the discharge duct 23 is
communicated with the feed duct 2.
[0096] And, a feed-pipe lower end portion 40 is formed integrally
with the feed pipe 34 so as to act as a closing member capable of
engaging with the communicating duct 37 and closing the same in
association with the engagement of the feed pipe 34 within the
engaging hole 36 thereby to close this communicating duct 37.
[0097] [Second Embodiment]
[0098] FIG. 4 shows principal portions of a feeding apparatus A
according to a further embodiment. In this, a feed pipe 34 is
connected to a feed-duct forming member 44 communicating with the
discharge duct 23 and a valve rod 20 includes a valve-element
portion 41 which is vertically slidable relative to the inner face
of the sleeve 26. The valve element 21 is vertically movable
between an inlet position in which the valve element portion 41 is
drawn out of the sleeve 26 thereby to establish communication
between the inlet duct 22 and the inlet/outlet duct 8 and also the
lower contact portion 31 comes into the annular contact with the
lower receiving seat 29 thereby to block communication between the
discharge duct 23 and the inlet/outlet duct 8 as shown in FIG. 4(a)
and an outlet position in which the lower contact portion 31
departs from the lower receiving seat 29 thereby to establish
communication between the discharge duct 23 and the inlet/outlet
duct 8 and also the valve element portion 41 becomes engaged within
the sleeve 26 thereby to block communication between the inlet duct
22 and the inlet/outlet duct 8 as shown in FIG. 4(b).
[0099] The rest of this construction is identical to that of the
first embodiment.
[0100] [Third Embodiment]
[0101] FIG. 5 shows a feeding apparatus A according to a further
embodiment for feeding the molten metal C of magnesium alloy as an
example of molten metal to the casting device B. Next, those
portions of this embodiment different from the first embodiment
will be explained.
[0102] As shown in FIG. 5, a feed pipe 34 is connected to a
feed-duct forming member 44 communicating with the discharge duct
23. A selector valve 3 is provided to be inserted into and removed
out of the casing body 9 from the above. The valve box 19 including
the discharge duct 23 communicating with the feed duct 2 and the
inlet-outlet duct 8 as openings at the lower portion of the
valve-element moving space 24 defines therethrough the inlet duct
22 communicating with the molten metal furnace D at the upper
portion of the valve-element moving space 24 which portion is
located at a higher position than the discharge duct 23.
[0103] And, a base member 42 extending continuously from the lower
portion of the casing body 9 forms a circular engaging hole (an
example of engaging portion) 43 within which the valve box 19 is
removably inserted from the above and fixed in position and an
intermediate portion of the inlet/outlet duct 8 is communicated
with the inside of the engaging hole 43. Further, a feed-duct
forming member 44 formed of ceramics (silicon nitride) is
bolt-fixed to the base member 42 and the feed duct 2 is
communicated with the inside of the engaging hole 43. As the valve
box 19 is engaged within the engaging hole 43 and fixed in position
therein, the inlet/outlet duct 8 is communicated with the cylinder
chamber 12 and the valve-element moving space 24 and also the feed
duct 2 is communicated with the discharge duct 23.
[0104] At the bottom of the engaging hole 43, there is formed a
communicating duct 45 capable of communicating with the molten
metal furnace D at a position lower than the feed duct 2 is formed
vertically through the valve box 19 along the inserting/withdrawing
direction. And, the valve box 19 forms, as a projection at the
lower end thereof, a closing member 46 engageable with the
communicating duct 45 for closing this duct 45 in association with
the engagement of the valve box 19 within the engaging hole 43.
[0105] The rest of the construction is identical to that of the
first embodiment.
[0106] [Fourth Embodiment]
[0107] FIG. 6 shows a further embodiment of a molten metal pump 1
and a selector valve 3 which are provided in a feeding apparatus A
for feeding to a casting device B molten metal C such as magnesium
alloy, aluminum alloy, zinc alloy etc. as an example of molten
metal. And, to a piston 5 of this molten metal pump 1, there is
attached a piston ring 74 as a sealing ring E according to the
present invention. Further, a valve rod 20 of the selector valve 3
is provided with a scraper 71 according to the present
invention.
[0108] The piston ring 74, as shown in FIG. 8, comprises a
heat-resistant member 81 having a quadrilateral cross section
formed by sintering of silicon nitride material and in the C shape
by cutting a portion thereof in the peripheral direction so as to
be radially elastically deformable. As shown also in FIG. 6,
between the inner peripheral face of the cylinder casing 4 and the
outer peripheral face of the piston 5, which are faces opposed to
each other in a direction normal to the moving direction of the
cylinder casing 4 and the piston 5 as a pair of members movable
relative to each other in one direction, the piston ring is
elastically deformed in the radially contracting direction so that
its peripheral face is pressed by its elastic resilience against
the inner peripheral face of the cylinder casing (one of the
members) 4 and also is fitted within an annular groove 5a defined
in the outer periphery of the piston 5, thereby to prevent relative
movement relative to the piston (the other member) 5 in the
reciprocating direction. Whereby, in association with a
reciprocating movement of the piston 5, the peripheral face is slid
relative to the inner peripheral face of the cylinder casing 4,
thereby to prevent displacement of the molten metal C through the
gap between the opposed faces.
[0109] And, a thickness size T of the heat-resistant member 81
along the ring diameter direction is set to be greater than 0.02
times and less than 0.2 times of the ring outer diameter K Further,
a width size H of the heat-resistant member 81 along the ring axis
direction X is set to be greater than 0.2 times and less than 1.5
times of the thickness size T. With these, sufficient strength and
sufficient elastic deformation amount in the radial direction are
assured. As a result, even when the piston 5 is moved together with
the piston ring 74 against heat-sticking force of the piston ring
74 relative to the cylinder casing 4, breakage of the piston ring
74 hardly occurs. Further, as shown in FIG. 9, even when an
abnormal condition develops that the piston 5 is reciprocated along
the cylinder axis Z with the piston axis Y being inclined relative
to the cylinder axis Z, thereby to result in increase in the
clearance between the outer peripheral face of the piston 5 and the
inner peripheral face of the cylinder casing 4, the sufficient
sealing effect can be assured and also sludge can be scraped off
sufficiently.
[0110] Referring now to the selector valve 3, the spool-type valve
element (an example of an operated member) 21 and its valve rod (an
example of an operating rod) 20 are formed together of ceramic
(silicon nitride) and connected substantially coaxial to each
other. Further, an inserting hole 62 into which the valve element
21 and the valve rod 20 are inserted to be vertically movable
therein is formed in the casing body 9 so that its upper end may be
open at a position below a liquid level lower than the liquid level
movable range of the molten metal C held within the molten metal
furnace D. And, the valve element 21 and the valve rod 20 are
inserted into the insertion hole 62 so that the valve rod 20 may
project upwardly from the upper end of the insertion hole 62.
[0111] The insertion hole 62 is formed such that an upper
large-diameter insertion hole 63 and a lower small-diameter
insertion hole 64 are connected via a tapered hole portion 65 whose
diameter varies with tapering. The lower end of the small-diameter
insertion hole 64 is closed by a valve plug 66. The small-diameter
insertion hole 64 forms a hole for allowing valve-element movement.
A molten metal inlet duct 22 is formed laterally to communicate
with the inside of the molten metal furnace D in the vicinity of
the lower end of the valve-element moving hole 64. A molten metal
discharge duct 23 communicating with the feed pipe 34 and the
inlet/outlet duct 8 are formed one above the other to be open to
the valve-element moving hole 64. And, a communicating duct 67 is
formed laterally to establish communication between the inside of
the molten metal furnace D and the large-diameter insertion hole
63.
[0112] The valve element 21, like the piston ring 74 shown in FIG.
8, includes a pair of upper and lower valve-element portions 69, 70
including a sealing ring 68 formed of ceramics (silicon nitride)
having C shape and in slidable contact to an inner peripheral face
of the valve-element moving hole 64. In operation, with a
vertically moving operation of the valve rod 20 by activation of
the valve-operating pneumatic cylinder 16, the valve element 21 is
vertically moved within the valve-element moving hole 64 so as to
switch over the duct for the molten metal C by varying the contact
condition relative to the inner face of the valve-element moving
hole between a condition (to be referred to as "inlet position"
hereinafter) to establish communication between the inlet duct 22
and the inlet/outlet duct 8 and also to block communication between
the discharge duct 23 and the inlet/outlet duct 8 by the lower
valve-element portion 70 as shown in FIG. 6 (a) and a further
condition (to be referred to as "outlet position" hereinafter) to
establish communication between the discharge duct 23 and the
inlet/outlet duct 8 and also to block communication between the
discharge duct 23 and the large-diameter insertion hole 63 by means
of the upper valve-element portion 69 and also to block
communication between the inlet duct 22 and the inlet/outlet duct 8
by means of the lower valve-element portion 70 as shown in FIG.
6(b).
[0113] And, as shown in FIG. 6(a), as the piston 5 is moved upward
with the valve element 21 being shifted to the inlet position, the
molten metal C held within the molten metal furnace D is drawn into
the cylinder chamber 12. Whereas, as shown in FIG. 6(b), as the
piston 5 is moved downward with the valve element 21 being shifted
to the outlet position, the molten metal C held within the cylinder
chamber 12 is discharged to the feed duct 2 of the feed pipe
34.
[0114] Around the outer periphery of the valve rod 20, there is
provided a scraper 71 which closes the gap between this valve rod
20 and the large-diameter insertion hole 63 and which is slidable
along the substantially entire periphery relative to the inner
peripheral face of the large-diameter insertion hole in association
with a vertically moving operation of the valve rod 20, with the
scraper 71 being provided such that it is moved to the vicinity of
the upper end of the large-diameter insertion hole 63 when the
valve element 21 is shifted to the upper end of the vertically
movable range thereof.
[0115] The scraper 71, as shown in FIG. 7, includes a ring member
72 formed of ceramics (silicon nitride) which is non-removably
fitted in an annular groove 20a defined in the outer periphery of
the valve rod 20, thereby to prevent intrusion of sludge such as
metal oxide generated in the vicinity of the liquid surface of the
molten metal in the molten metal furnace D to the vicinity of the
valve element 21. Further, even when sludge becomes adhered to the
inner peripheral face of the large-diameter insertion hole, this
sludge can be scraped off by a vertical sliding movement of the
ring member 72 relative to the inner peripheral face of the
large-diameter insertion hole in association with the operation of
the valve element 21.
[0116] The ring member 72, like the piston ring 74 shown in FIG. 8,
is radially elastically deformable by cutting a peripheral portion
of the ring by a substantially constant width into the shape of C.
And, this ring member 72 is elastically deformed in the radially
inward direction (diameter reducing direction) to be fitted in the
large-diameter insertion hole 63, so that the ring is pressed and
contacted by means of its own elastic resilience, against the inner
peripheral face of the large-diameter insertion hole.
[0117] Incidentally, since cut end faces 73 of the ring member 72
are formed each with an inclination along the peripheral direction
so as to be relatively movable along the peripheral direction with
these end faces 73 being opposed to each other in the sliding
direction, it is possible to effectively prevent introduction of
the sludge together with the molten metal C through the cut portion
of the ring member 72 to the side of the valve element 21.
[0118] Incidentally, in the foregoing embodiment, the cylinder
casing 4, the piston 5, the piston rod 6, the piston ring 74, the
connecting arm 15, the valve element 21, the valve rod 20, the
sealing ring 68 and the ring member 72 are formed of silicon
nitride. However, when the molten metal C comprises molten metal of
magnesium alloy, a steel type material such as SKD may be used.
Further, a surface treatment such as an aluminizing treatment may
be effected on these components if appropriate.
[0119] The rest of the construction is identical to the first
embodiment.
[0120] [Fifth Embodiment]
[0121] Though not shown, in place of the piston ring 74 shown in
the seventh embodiment which comprises the heat-resistant member 81
formed of silicon nitride, it is possible to provide a piston ring
74 comprising a heat-resistant member 81 formed by sintering a
composite material of a metal material such as titanium (Ti) or the
like and a ceramic material such as titanium carbide (TiC).
[0122] The rest of the construction is identical to the fourth
embodiment.
[0123] [Sixth Embodiment]
[0124] FIG. 10 shows a further embodiment of the piston ring 74 as
the sealing ring E. In this case, the heat-resistant member 81 has
a cross sectional shape which is provided as a trapezoid having two
sides 81a, 81b extending parallel with each other along the ring
axis X direction. And, as shown in FIG. 10(b), the longer side 81b
of the two sides 81a, 81b parallel with each other is engaged into
a dovetail groove 5b formed like a ring in the outer peripheral
portion of the piston (the other member) 5 and a peripheral face of
the shorter side 81a of the two sides 81a, 81b parallel with each
other is placed in pressed contact against the cylinder casing (one
member) 4.
[0125] The rest of the construction is identical to that of the
fourth or the fifth embodiment.
[0126] [Seventh Embodiment]
[0127] FIG. 11 shows another example of the molten metal pump 1
shown in the fourth embodiment. In this case, the cylinder casing 4
includes a cylindrical casing body 9 formed of ceramics (silicon
nitride) having a lower opening 82 open into the molten metal C
held within the molten metal furnace D and a circular casing top
plate 83 formed of ceramics (silicon nitride) for closing the top
opening of the casing body 9. And, inside the casing body 9 between
the piston 5 formed of ceramics (silicon nitride) having the piston
ring 74 like that shown in the seventh embodiment and the casing
top plate 83, there is formed a cylinder chamber 12 and an
inlet/outlet duct 8 communicating with the cylinder chamber 12 is
formed.
[0128] At the upper end of the casing body 9, there is integrally
formed a cylindrical spacer 84 and this cylindrical spacer 84 is
secured to a furnace lid 13 of the molten metal furnace D. And, the
cylinder casing 4 is secured so that this entire cylinder casing 4
may be submerged in the molten metal C at a position lower than a
lowermost liquid level L of the liquid level movable range of the
molten metal C within the molten metal furnace D.
[0129] To the top of the cylindrical spacer 84, there is fixed a
cylindrical member 85 formed of ceramics (silicon nitride) operable
to press the casing top place 83 against the casing body 9 from the
above. Further, a bearing member 87 formed of ceramics (silicon
nitride) having a bearing cylindrical portion 86 for vertically
movably supporting the piston rod 6 is fixed so as to close the
inside of the cylindrical member 85. And, the piston rod 6 is
inserted through the bearing cylindrical portion 86 and an
insertion hole 88 defined in the casing top plate 83, with the
piston rod 6 being vertically movable back and forth. In operation,
as the piston 8 is reciprocated by a vertical reciprocating
operation of the piston rod 6, the molten metal C drawn into the
cylinder chamber 12 via the inlet/outlet duct 8 can be discharged
via the inlet/outlet duct 8 into the feed pipe 34 to be fed
eventually to the casting device B.
[0130] And, as shown also in FIG. 12, between the opposing faces of
the piston rod 6 and the casing top plate 83 in the direction
normal to the moving direction provided as a pair of members which
can reciprocate relative to each other in one direction, a sealing
ring E according to the present invention is radially elastically
deformed and fitted within an annular groove 89 defined in the
inner periphery of the through hole 88 so that its peripheral face
is pressed and contacted by the elastic resilience thereof against
the piston rod (one member) 6 and its relative movement relative to
the casing top plate (the other member) 83 in the reciprocating
direction is prevented. In operation, in association with a
reciprocating movement of the piston rod 6 relative to the casing
top plate 83, the peripheral face is slid relative to the piston
rod 6, thereby to prevent displacement of the molten metal C via
the gap between the opposing faces. As a result, it is possible to
prevent introduction of the molten metal C via the gap between the
opposing faces when the molten metal C is to be drawn into the
cylinder chamber 12 and also to prevent leakage of the molten metal
C via the gap between the opposing faces when the molten metal C
drawn into the cylinder chamber 12 is to be fed to the casing
device B. Moreover, sludge of the molten metal C stuck to or
accumulated on the peripheral face of the piston rod 6 may be
scraped away by the sealing ring E, thereby to avoid the trouble of
the sealing ring E becoming heat-stuck to the piston rod 6 via such
sludge.
[0131] The rest of the construction is identical that of any one of
the fourth through sixth embodiments.
[0132] Sealing rings (to be referred to as Samples 1-13
hereinafter) having differing dimensions of different combinations
of the ring outer diameter K of the sealing ring E, the thickness T
of the heat-resistant member 81 along the ring radial direction and
the width H of the same along the ring axial direction were made
and these rings were fitted respectively as the piston rings 74 to
the piston 5 of the molten metal pump 1 described in the seventh
embodiment. And, the pump was continuously operated with each
sample and the running time period until each of Samples 1-13
became damaged or heat-stuck to the cylinder casing 4 was
measured.
[0133] [Table 1] shows the results of this study. As shown, with
Samples 8 and 9 in which the ratio (T/K) of the thickness T
relative to the ring outer diameter K is not greater than 0.02, the
samples were broken after about one month running time period. And,
with Sample 11 in which the ratio (T/K) of the thickness T relative
to the ring outer diameter K exceeds 0.2, the piston rod 6 was
deformed after about one month running time period and became
heat-stuck to the cylinder casing 4.
[0134] Further, of Samples 1-7, Sample 10 and Samples 12, 13 in
which the ratio (T/K) of the thickness T relative to the ring outer
diameter K is greater than 0.02 and less than 0.2, in the case of
Samples 10 and 12 in which the ratio (H/T) of the width H relative
to the thickness T is not greater than 0.2, heat-sticking to the
cylinder casing 4 occurred after about one month running time
period. With Sample 13 in which the ratio (H/T) of the width H
relative to the thickness T exceeds 1.5, it was broken after about
one month running time period. On the other hand, of those samples
in which the ratio (T/K) of the thickness T relative to the ring
outer diameter K is greater than 0.02 and less than 1.5, in the
case of Samples 1-7 in which the ratio (H/T) of the width H
relative to the thickness T is greater than 0.2 and less than 1.5,
they exhibited good result with no damage or no heat-sticking even
after more than 6 months of running time period. Hence, it was
found that with these good durability and sealing performance can
be readily secured.
[0135] Incidentally, the mark SN shown in the column of material
denotes ceramics formed by sintering of silicon nitride having
hardness of 90 HRA and density of 3.2. The further mark MC denotes
metal ceramics formed by sintering of composite material of
titanium (Ti) and titanium carbide (TiC).
1TABLE 1 ring outer width diameter thickness H running Sample K
(mm) T (mm) (mm) T/K H/T material time Sample 45 5.0 6 0.11 0.83 SN
more 1 than 6 months Sample 80 5.0 8 0.063 0.63 SN more 2 than 6
months Sample 45 1.5 5 0.03 0.30 MC more 3 than 6 months Sample 80
2.5 10 0.031 0.25 MC more 4 than 6 months Sample 50 8.5 42 0.17
0.20 SN more 5 than 6 months Sample 50 2.5 2.5 0.05 1.0 SN more 6
than 6 months Sample 45 4.5 3 0.10 1.5 SN more 7 than 6 months
Sample 50 1.0 5 0.018 0.20 SN broken 8 after 1 month Sample 80 1.5
10 0.019 0.15 MC broken 9 after 1 month Sample 45 4.0 50 0.09 0.08
SN heat- 10 stuck after 1 month Sample 45 9.9 8 0.22 1.24 SN stuck
11 due to defor- mation of piston rod Sample 80 2.5 128 0.031 0.019
SN stuck 12 after 1 month Sample 80 4.0 2.5 0.05 1.6 SN broken 13
after 1 month
[0136] [Eighth Embodiment]
[0137] FIG. 13 shows a further embodiment of the ring member 72. In
this, each cut end face 73 is formed like a hook having a
peripheral-direction end face portion 73a having a long extension
along the peripheral direction and a sliding-direction end face
portion 73b having a long extension along the sliding direction and
formed at opposed ends of the peripheral-direction end face portion
73a. In operation, with radial elastic deformation, the
peripheral-direction end face portions 73a opposed to each other in
the sliding direction slide and move along the peripheral
direction. As a result, it is possible to effectively prevent the
sludge together with the molten metal C from moving via the cut
portion of the ring member 72 to the side of the valve element 21
or the piston 5.
[0138] [Ninth Embodiment]
[0139] FIG. 14 shows principal portions of a further embodiment of
a feeding apparatus A for feeding molten metal C to the casting
device B. In this, the insertion hole 62 into which the valve
element (an example of the operated member) 21 and the valve rod
(an example of the operating rod) 20 of the selector valve 3 are
inserted comprises an upper small-diameter insertion hole 90 and a
lower large-diameter insertion hole 91 which are connected via a
tapered hole portion like that of the seventh embodiment. So that,
the valve-element moving hole is formed by the portion extending
from a vertically intermediate portion of the small-diameter
insertion hole 90 to the large-diameter insertion hole 91. And, a
molten-metal discharge duct 23 communicating with the feed pipe 34
is open to the bottom of the large-diameter insertion hole 91 and
the inlet/outlet duct 8 is open at a vertically intermediate
portion of the large-diameter insertion hole 91, and, a
molten-metal inlet duct 22 is formed laterally to establish
communication between the inside of the molten metal furnace D and
the small-diameter insertion hole 90.
[0140] The valve element 21 includes a lower sliding valve-element
portion 92 in which a C-shaped ceramic sealing ring 63 is disposed
to come into sliding contact with the inner peripheral face of the
small-diameter insertion hole 90 and a contact valve-element
portion 93 which comes into contact with a valve seat 94 formed at
the bottom of the large-diameter insertion 91. In operation, as the
valve element 21 is vertically moved by a vertically moving
operation of the valve rod 20 with activation of the valve
operating pneumatic cylinder 16, the duct for the molten metal C
can be switched over by changing the contact condition relative to
the inner face of the valve-element moving hole between a condition
(to be referred to as "inlet position" hereinafter) for
establishing communication between the inlet duct 22 and the
inlet/outlet duct 8 and also blocking communication between the
discharge duct 23 and the inlet/outlet duct 8 by the contact
valve-element portion 93 as shown in FIG. 14(a) and a further
condition (to be referred to as "outlet position" hereinafter) for
establishing communication between the discharge duct 23 and the
inlet/outlet duct 8 and also blocking communication between the
inlet duct 22 and the inlet/outlet duct 8 by means of the lower
sliding valve-element portion 92 as shown in FIG. 14(b).
[0141] And, at an upper portion of the lower sliding valve-element
portion 92, there is provided an upper sliding valve-element
portion 95. A sealing ring 68 slidable along substantially entire
periphery of the inner peripheral face of the small-diameter
insertion hole in association with a vertically moving operation of
the valve rod 20 is provided to move to the vicinity of the upper
end of the small-diameter insertion hole 90 when the valve element
21 is shifted to the upper end of its vertically movable range.
[0142] Further, referring to the molten metal pump 1, a piston (an
example of the operated member) 5 fitted with a piston ring 74
formed of ceramics (silicon nitride) and its piston rod (an example
of the operating rod) 6 are formed together of ceramics (silicon
nitride) and connected substantially coaxially. Further, a
cylinder-chamber forming through hole (an example of the insertion
hole) 10 into which the piston 5 and the piston rod 6 are inserted
to be vertically movable therein is formed with a substantially
constant inner diameter in the casing body 9 so that its upper end
may be open below a liquid level lower than the liquid level
movable range of the molten metal C held within the molten metal
furnace D. The piston 5 and the piston rod 6 are inserted into the
cylinder-chamber forming through hole 10 so that the piston rod 6
may project upwardly from the upper end of the cylinder-chamber
forming through hole 10.
[0143] Referring to the cylinder-chamber forming through hole 10,
its lower end is closed by the cylinder plug 11 and the lower
portion of this cylinder-chamber forming through hole 10 forms a
piston moving hole. Hence, the piston rod 5 is vertically slid by a
vertically moving operation of the piston rod 6 associated with
activation of the piston driving pneumatic cylinder 7. As shown in
FIG. 14(a), as the piston 5 is moved upward with the valve element
21 being shifted to the inlet position, the molten metal C held
within the molten metal furnace D is drawn into the piston moving
hole. Whereas, as shown in FIG. 14(b), as the piston 5 is moved
downward with the valve element 21 being shifted to the outlet
position, the molten metal C held within the piston moving hole is
discharged to the feed pipe 34.
[0144] The piston rod 6 includes a small-diameter rod 75 connected
to the piston driving pneumatic cylinder 7 and a large-diameter rod
76 formed as an upper extension of the piston 5. On the outer
periphery of the large-diameter rod 76, there is attached a scraper
71 for closing the gap between the large-diameter rod 76 and the
cylinder-chamber forming through hole 10 and being slidable along
substantially entire periphery of the inner peripheral face of the
cylinder-chamber forming through hole in association with a
vertically moving operation of the piston rod 6, the scraper 71
being moved to the vicinity of the upper end of the
cylinder-chamber forming through hole 10 when the piston 5 is
shifted to the upper end of its vertically movable range.
[0145] Referring to the scraper 71, like the one disclosed in the
fourth embodiment, a ring member 72 formed of ceramics (silicon
nitride) formed as a C-shaped member by cutting one peripheral
portion is non-removably attached on the outer periphery of the
large-diameter rod 76 and this ring member 72 is elastically
deformed to the radially inward side to be fitted within the
cylinder-chamber forming through hole 10 and pressed against the
inner peripheral face of the cylinder-chamber forming through
hole.
[0146] The rest of the construction is identical to the first
embodiment.
[0147] [Other Embodiments]
[0148] 1. The invention's feeding apparatus for molten metal can be
used also for feeding molten metal of aluminum, zinc, tin, etc. to
a casting mold.
[0149] 2. In the invention's feeding apparatus for molten metal, at
the bottom of the engaging portion, a communicating duct capable of
communicating with the molten metal furnace can be laterally formed
therethrough.
[0150] 3. The invention's feeding apparatus for molten metal can be
used also for feeding the molten metal to a ladle provided in the
casting device.
[0151] 4. The invention's feeding apparatus for molten metal can be
used also for feeding molten metal of aluminum, zinc, tin, etc.
[0152] 5. In the invention's feeding apparatus for molten metal,
the scraper may include a metal ring member formed of e.g. titanium
(Ti) non-removably attached on the outer periphery of the operating
rod, with this ring member being elastically deformed to the
radially inward side to be fitted within the insertion hole.
[0153] 6. In the invention's feeding apparatus for molten metal,
the operated member comprises a valve element which is vertically
moved within the valve-element moving hole by a vertically moving
operation of the valve rod as the operating rod whereby the duct is
switched over only by its contact with a valve seat formed in the
inner face of the valve-element moving hole.
[0154] 7. In the invention's feeding apparatus for molten metal,
the piston rod acting as the operating rod may be formed with a
smaller diameter than the outer diameter of the piston acting as
the operated member.
INDUSTRIAL APPLICABILITY
[0155] The invention relates to a feeding apparatus for molten
metal and is useful for improvement of precision of molten metal
feeding operation and maintenance.
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