U.S. patent number 3,746,483 [Application Number 05/240,256] was granted by the patent office on 1973-07-17 for reciprocating piston pump.
This patent grant is currently assigned to Pumpenfabrik Urach. Invention is credited to Hugo Fries, Hans Hindel.
United States Patent |
3,746,483 |
Hindel , et al. |
July 17, 1973 |
RECIPROCATING PISTON PUMP
Abstract
A reciprocating piston pump having a pump housing with an axial
bore of two different diameters separated by an annular shoulder
and a cylinder at the end of the narrower part of the bore in which
a piston is movable, and a valve housing inserted into the bore and
having an annular shoulder which is formed between an enlarged part
and narrower part of the valve housing and is pressed against the
shoulder of the pump housing. For preventing varying stresses from
being exerted especially upon this shoulder area of the valve
housing and for making the latter of a very compact size, the
invention provides the pump chamber between the piston and one end
of the valve housing and containing a suction valve for opening and
closing suction channels in the valve housing, a pressure-valve
chamber of a smaller diameter than that of the pump chamber axially
beyond the other end of the valve housing, a flow channel extending
longitudinally through the valve housing from the pump chamber to
the pressure-valve chamber and terminating at this other end in a
valve seat for the pressure valve the valve stem of which extends
through the flow channel, and a compensating chamber which
communicates through transverse channels with the flow channel and
is formed between the other end of the enlarged part of the valve
housing and the rim part of a cup-shaped plug which is inserted
into and closes the open end of the wider part of the bore in the
pump housing, while the bottom wall and the adjacent inner wall
parts of the plug together with the end wall of the narrowest part
of the valve housing define the pressure-valve chamber. Both valves
are adapted to be closed at the respective strokes of the piston by
a single spring one end of which acts upon the suction valve and
the other end upon a spring bearing which is mounted on the end of
the valve shaft in the pump chamber.
Inventors: |
Hindel; Hans (Urach,
DT), Fries; Hugo (Urach, DT) |
Assignee: |
Pumpenfabrik Urach
(Wurttemberg, DT)
|
Family
ID: |
5804588 |
Appl.
No.: |
05/240,256 |
Filed: |
March 31, 1972 |
Foreign Application Priority Data
|
|
|
|
|
Apr 13, 1971 [DT] |
|
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P 21 17 841.6 |
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Current U.S.
Class: |
417/571;
137/512.5; 137/512.3 |
Current CPC
Class: |
F04B
53/109 (20130101); Y10T 137/7842 (20150401); Y10T
137/7845 (20150401) |
Current International
Class: |
F04B
53/10 (20060101); F04b 039/10 (); F16k
015/00 () |
Field of
Search: |
;417/569,558,571
;137/512.2,512.3,512.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Freeh; William L.
Claims
Having thus described our invention, what we claim is:
1. A reciprocating piston pump, especially for high pressures,
comprising a pump housing having an aperture therein, said aperture
having a radially larger part and a radially smaller part axially
separated by a shoulder from each other, a valve housing inserted
into said aperture and having a radially enlarged part and a
radially smaller part axially extending from one end of said
enlarged part and separated from it by a shoulder abutting against
said shoulder on the wall of said aperture in said pump housing, a
pump chamber defined by a wall portion of said smaller aperture
part of said pump housing and by the end of said smaller part of
said valve housing, a flow channel extending through said valve
housing for passing a pressure medium therethrough, suction channel
means adapted to communicate with said pump chamber, a suction
valve in said pump chamber for controlling said suction channel
means, a pressure valve on said valve housing for controlling said
flow channel, closure wall means closing said aperture in said pump
housing at the side thereof opposite to the side of said valve
housing facing said pump chamber, a pressure-valve chamber between
said valve housing and said closure wall means and located behind
said pressure valve, as seen in the direction of flow of said
pressure medium from said pump chamber, and a compensating chamber
separate from said pressure-valve chamber and communicating with
said flow channel between said pump chamber and said pressure-valve
chamber, said compensating chamber having a wall forming the other
end of said enlarged part of said valve housing so that the
pressure medium contained in said compensating chamber will act
upon said other end of said enlarged part in the same direction as
the pressure medium contained in said pressure-valve chamber acts
upon said valve housing so as to press said valve housing in the
direction toward said pump chamber and thereby to press said
shoulder of said valve housing against said shoulder on the wall of
said aperture in said pump housing, the surface area of said valve
housing acted upon in said direction by said pressure medium in
said pressure-valve chamber and in said compensating chamber being
larger than the surface area of said valve housing acted upon by
said pressure medium in the opposite direction.
2. A reciprocating piston pump as defined in claim 1, in which said
surface area of said valve housing acted upon by the pressure
medium in said compensating chamber in said direction toward said
pump chamber has such a size that the difference between the
surface areas of said valve housing acted upon by the pressure
medium in said opposite direction in said pump chamber and in said
first direction in said compensating chamber is at least
substantially equal to the surface area of said valve housing acted
upon by said pressure medium in said first direction in said
pressure-valve chamber.
3. A reciprocating piston pump as defined in claim 1, in which said
valve housing has a second radially smaller part axially extending
from the other end of said radially larger part, said compensating
chamber forming an annular chamber surrounding the part of said
second smaller part adjacent to said other end of said larger
part.
4. A reciprocating piston pump as defined in claim 3, in which said
flow channel extends substantially axially through said valve
housing, said valve housing having channel means extending
substantially transverse to said flow channel and connecting the
same to said compensating chamber.
5. A reciprocating piston pump as defined in claim 1, in which said
suction channel means are provided in said valve housing and
consist of longitudinal channels and transverse channels each
having one end terminating into the associated channel, and further
suction channel means in said pump housing, the other ends of said
transverse channels being open at the outer periphery of said
enlarged part of said valve housing and communicating with said
further suction channel means, and the other ends of said
longitudinal channels adapted to be opened and closed by said
suction valve.
6. A reciprocating piston pump as defined in claim 5, in which said
flow channel extends substantially axially through said valve
housing, and said suction channel means in said valve housing
extend radially outside of and around said flow channel, said
suction valve forming an annular valve.
7. A reciprocating piston pump as defined in claim 6, in which said
suction valve and said pressure valve are provided at the opposite
ends of said valve housing, a valve shaft secured to a first of
said valves and extending through said valve housing and also
through and projecting from the other valve, a spring bearing
mounted on the projecting end of said valve shaft, and a common
valve spring having one end acting upon said other valve and
another end acting upon said spring bearing, said valve spring
tending to close both of said valves on said valve housing.
8. A reciprocating piston pump as defined in claim 7, in which said
pressure valve is secured to one end of said valve shaft.
9. A reciprocating piston pump as defined in claim 7, in which said
other valve is slidable along and guided by said valve shaft of
said first valve.
10. A reciprocating piston pump as defined in claim 1, in which
said closure wall means forms an insert inserted into said aperture
and secured to said pump chamber and having an inner end surface
forming a second wall opposite to and axially spaced from said
first wall of said compensating chamber and defining the latter
between said two walls, said insert containing said pressure-valve
chamber having an outer diameter smaller than that of said
compensating chamber.
11. A reciprocating piston pump as defined in claim 10, in which
said valve housing has a second radially smaller part axially
extending from the other end of said enlarged part and having a
smaller diameter than said first part, said insert being
cup-shaped, the rim part of said cup forming said second wall of
said compensating chamber, the inner wall surface of the recess of
said cup containing the free end of said second smaller part and
further defining the side wall of said pressure-valve chamber which
is further defined by the bottom of said cup and the free end wall
of said second smaller part of said valve member, said free end
wall into which said flow channel terminates forming a valve seat,
said pressure valve projecting into said pressure-valve chamber and
adapted to open and close said valve seat, and transverse outlet
channel means extending from said pressure-valve chamber through
the side wall of said cup and communicating with further outlet
channel means in said pump housing.
12. A reciprocating piston pump as defined in claim 11, in which
said insert has an outer diameter equal to the diameter of said
radially larger part of said aperture in said pump housing.
13. A reciprocating piston pump, especially for high pressures,
comprising a pump housing having an aperture therein, said aperture
having a radially larger part and a radially smaller part axially
separated by a shoulder from each other, a valve housing inserted
into said aperture and having a radially enlarged part and a
radially smaller part axially extending from one end of said
enlarged part and separated from it by a shoulder abutting against
said shoulder on the wall of said aperture in said pump housing, a
pump chamber defined by a wall portion of said smaller aperture
part of said pump housing and by the end of said smaller part of
said valve housing, flow channel means extending from said chamber,
suction channel means adapted to communicate with said pump
chamber, a suction valve in said pump chamber for controlling said
suction channel means, a pressure valve for controlling said flow
channel means, closure wall means closing said aperture in said
pump housing at the side thereof opposite to the side of said valve
housing facing said pump chamber, a pressure-valve chamber between
said valve housing and said closure wall means and located behind
said pressure valve, as seen in the direction of flow of said
pressure medium from said pump chamber, and a compensating chamber
separate from said pressure-valve chamber and communicating with
said flow channel means between said pump chamber and said
pressure-valve chamber, said compensating chamber having a wall
forming the other end of said enlarged part of said valve housing
so that the pressure medium contained in said compensating chamber
will act upon said other end of said enlarged part in the same
direction as the pressure medium contained in said pressure-valve
chamber acts upon said valve housing so as to press said valve
housing in the direction toward said pump chamber and thereby to
press said shoulder of said valve housing against said shoulder on
the wall of said aperture in said pump housing, the surface area of
said valve housing acted upon by the pressure medium in said
compensating chamber in said direction toward said pump chamber has
such a size that the difference between the surface areas of said
valve housing acted upon by the pressure medium in said opposite
direction in said pump chamber and in said first direction in said
compensating chamber is substantially equal to the surface area of
said valve housing acted upon by said pressure medium in said first
direction in said pressure-valve chamber.
14. A reciprocation piston pump as defined in claim 13, in which
said flow channel means extends substantially axialy through said
valve housing, said valve housing having channel means extending
substantially transverse to said flow channel and connecting the
same to said compensating chamber.
Description
The present invention relates to a reciprocating piston pump,
especially for high pressures, which comprises a pump chamber, a
valve housing which is inserted into the pump housing and is
axially supported thereon, a suction valve for controlling a
suction channel, a pressure valve within or on the valve housing, a
valve chamber for the pressure valve which is located behind the
latter, as seen in the direction of flow of the pressure medium
through the pump, and behind the end of the valve housing opposite
to the end facing the pump chamber, and a flow channel which
connects the pump chamber and the pressure-valve chamber and is
controlled by the pressure valve.
Due to the variation of the pressures alternating at every reversal
of the piston stroke, such a valve housing which is inserted into
the pump housing is subjected to very high stresses which may cause
the valve housing to crack and to be prematurely destroyed. This
danger increases in accordance with the height of the pressure
produced by the pump and the speed of its operation, and its occurs
especially at such points where a transverse bore in the valve
housing joins a longitudinal bore, for example, the intake bore of
the medium to be pumped, or where sudden angular changes occur in
the outer diameters of the valve housing. If the valve housing is
supported, for example, at such or similar endangered points in the
axial direction on the pump housing in order to take up the
alternating forces acting upon the valve housing, the alternating
stresses occurring at these points may become so high as to exceed
the breaking limits of the material.
It is the principal object of the present invention to eliminate
this danger of excessive stresses acting upon the valve housing of
a reciprocating piston pump or upon other housings which are
subjected to similar stresses which are caused by alternating
forces which are changing in direction and strength.
An important feature of the invention therefore consists in
providing the pump with a compensating chamber in which the
pressure medium acts upon the valve housing in the same general
direction as the pressure medium which is located in the valve
chamber of the pressure valve and in the opposite direction to the
pressure medium which is contained in the pump chamber and acts
upon the valve housing, so that during the suction and compression
strokes of the pump the valve housing will be pressed with
substantially the same force and in the same direction against an
axial supporting surface of the pump housing.
According to one preferred embodiment of the invention, this
purpose is attained by providing the pump housing with an axial
bore or channel, one end part of which forms the cylinder for the
reciprocating piston and the pump chamber, while the other end part
has a larger outer size so as to form an intermediate shoulder.
Into this bore the valve housing is inserted from the wider end. A
central part of this valve housing is likewise made of a larger
outer size and its end facing the pump chamber forms a shoulder
which abuts against the first mentioned shoulder in the pump
housing, while the other end of this enlarged part forms one end
wall of a compensating chamber which communicates through a channel
with the pump chamber. The wider end of the bore in the pump
housing is closed by a cup-shaped plug member the inner recess of
which receives the reduced other end of the valve housing which
also forms the valve seat for the pressure valve, while between
this other end of the valve housing and the bottom of the recess in
the plug member the valve chamber for the pressure valve is formed.
The opposite end wall of the compensating chamber is formed by the
inner end surface of the plug member. The effective end surfaces of
the valve housing which are acted upon by the pressure medium are
therefore formed by the parts of the valve housing directly facing
the pump chamber, the annular end surface of the enlarged part of
the valve housing which forms one wall of the compensating chamber,
and the end parts of the valve housing facing the valve chamber of
the pressure valve in the recess in the plug member. According to
the invention, these effective end surfaces are made of such
dimensions that the difference in size between the effective end
surfaces of the valve housing upon which the pressure medium acts
in one axial direction within the pressure-valve chamber and in the
compensating chamber and in the opposite axial direction within the
pump chamber is equal or substantially equal to the effective size
of the end surface of the valve housing facing the pressure-valve
chamber.
The result of these features is as follows:
During the suction stroke of the piston when the suction valve is
opened and the pressure valve is closed so that the pump chamber
and the valve chamber of the pressure valve are closed relative to
each other, a suction pressure prevails in the pump chamber and
also in the compensating chamber, while in the pressure-valve
chamber a high pressure prevails. The valve housing is therefore
pressed in the direction toward the pump chamber, that is, in the
direction of the suction stroke, and the shoulder on the valve
housing is pressed against the corresponding shoulder of the pump
housing with an axial force which is exerted by the high pressure
of the pressure medium upon the effective end surface of the valve
housing in the pressure-valve chamber. The strength of the
pressures which actually occur during the suction strokes in the
pump chamber and in the compensating chamber are generally of no
particular consequence.
During the compression stroke of the piston, however, when the
suction valve is closed and the pressure valve is opened, the axial
pressure which is exerted upon the valve housing in the
pressure-valve chamber is opposed by the same pressure which acts
in the pump chamber upon the other end of the valve housing.
However, this pressure in the pressure-valve chamber is at the same
time increased by the pressure which acts in the same direction in
the compensating chamber upon the end wall thereof which is formed
by the enlarged central part of the valve housing. The effective
pressure during the compression strokes is therefore the difference
in the pressure acting in one direction upon the valve housing
within the compensating chamber and the pressure acting in the
opposite direction in the pump chamber. Since according to the
invention this pressure difference is equal or substantially equal
in strength and direction to the axial pressure which is exerted by
the pressure medium upon the valve housing during the suction
strokes of the piston, no or at least no substantial change of
pressure will ever occur on the abutting shoulders of the valve
housing and pump housing and alternating stresses upon this part of
the valve housing will thus be fully or practically avoided.
This relief of the shoulder of the valve housing from alternating
pressures is especially of importance if this shoulder is located
adjacent to transverse or longitudinal channels, for example, the
transverse and longitudinal intake channels which extend from the
intake line in the pump housing through the valve housing to the
suction valve for supplying the medium to be pumped into the pump
chamber during the suction strokes of the piston.
It is a further object of the invention to provide a valve unit
which is designed so as to take up a very small space. For
attaining this object, the invention provides that the channel
which connects the pump chamber with the pressure-valve chamber and
which is controlled by the pressure valve extends substantially
centrally in the axial direction through the valve housing, that
the intake or suction channel means which preferably consists of
interconnected transverse channels and longitudinal channels are
located around the main central channel, and that the suction valve
preferably consists of an annular valve which projects into the
pump chamber.
According to a very advantageous embodiment of the invention, both
valves, that is, the pressure valve and the suction valve, extend
coaxially to each other on the valve housing and both valves are
closed in opposite directions to each other during the respective
strokes of the piston by means of a common valve spring. One of
these valves, that is in this case the pressure valve, is for this
purpose preferably secured to one end of a valve shaft which
extends through the central channel of the valve housing and
through the other valve, that is, in this case the annular suction
valve and the valve spring thereon, while the other end of this
valve shaft carries a bearing member for the other end of the valve
spring. The actual channel means through which the pressure medium
flows during the compression strokes from the pump chamber to the
pressure-valve chamber preferably consist of longitudinal grooves
which are provided in the shaft of the pressure valve which is
slidable along the wall of the central channel. The valve structure
according to the invention therefore has not only the advantage of
being very compact, but also of only requiring a single valve
spring for both valves.
These and additional features and advantages of the present
invention will become further apparent from the following detailed
description thereof which is to be read with reference to the
accompanying drawings, in which-
FIG. 1 shows a central longitudinal section of a part of a
reciprocating pump containing a valve housing according to the
invention; while
FIG. 2 shows a cross section which is taken along the line 2 -- 2
in FIG. 1 .
As illustrated in the drawings, the pump housing 10 is provided
with a bore 11 forming the cylinder in which a plunger piston 12 is
movable back and forth so as first to carry out a suction stroke in
the direction of the arrow x.sub.1 and then a compression stroke in
the direction of the arrow x.sub.2. This bore 11 terminates in the
direction of the arrow x.sub.2 into a larger bore 13 and the latter
into a still larger bore 14. From the left of FIG. 1, a valve
housing 15 the outer diameters of which correspond to the diameters
of bores 13 and 14 are inserted in the axial direction into these
bores so that an annular shoulder 16 on valve housing 15 abuts in
the direction of the arrow x.sub.1 against a corresponding shoulder
between the adjacent ends of bores 13 and 14. The left end of bore
14 is closed toward the outside by a cup-shaped plug member 17
which is prevented from turning or shifting in its axial direction
by any suitable means, not shown.
The free parts of bores 11 and 13 between the end of piston 12 and
valve housing 15 define a pump chamber 18 the volume of which
alternately increases and decreases in accordance with the
reciprocating movements of piston 12. Between the left end of valve
housing 15 and the inner bottom of the cup-shaped plug member 17,
as seen in FIG. 1, a valve chamber 19 is formed. This valve chamber
19 is connected by transverse bores in plug member 17 and an
annular channel 20 with a pressure delivery line 21 which in a
multiple-cylinder pump may extend to the cylinder heads of all
cylinders.
Valve housing 15 is provided with a continuous central axial
channel 22 which connects the pump chamber 18 with the valve
chamber 19. This valve chamber 19 contains a pressure valve 23
which is operatively associated with a conical valve seat 24 in the
left end of valve housing 15 and controls the connection between
pump chamber 18 and the pressure-valve chamber 19 via the channel
22. Valve 23 is secured to one end of a valve shaft 25 which is
provided with, for example, four guide webs 26 which are slidable
axially along the wall of channel 22 and are separated from each
other by longitudinal grooves 27, as shown particularly in FIG. 2,
through which the medium to be pumped may flow from the pump
chamber 19 when the pressure valve 23 is opened by being lifted off
its valve seat 24 during each compression stroke of piston 12.
On its end projecting into the pump chamber 18, shaft 25 of the
pressure valve 23 carries an annular suction valve 28 which is
slidable thereon in the axial direction and controls the connection
between the pump chamber 18 and the suction valve channels 29 which
are provided in the valve housing 15 and consist of longitudinal
channels 30 and transverse channels 31. These transverse channels
31 communicate with one or more suction lines 33 through an annular
channel 32 which is provided in the wall of bore 14 adjacent to the
annular shoulder 16.
For closing the suction valve 28 as well as the pressure valve 23 a
single valve spring 34 is provided one end of which acts directly
upon the suction valve 28 and its other end upon a spring bearing
35 which is mounted on the end of valve shaft 25 which projects
into the pump chamber 18. Spring 34 thus tends to press the two
valves 28 and 23 in opposite directions upon their valve seats by
means of the spring bearing 35 and the valve shaft 25, that is, the
suction valve 28 upon a flat valve seat 36 which is formed by the
end surface of valve housing 15 facing the pump chamber 18, and the
pressure valve 21 upon the conical valve seat 24.
Channel 22 further communicates, preferably through an annular
groove 36 in the wall of channel 22 and transverse bores 37 in
valve housing 15 with an annular compensating chamber 38 which is
located between the valve housing 15 and the inner end of the plug
member 17. The pressure medium which is contained in the
compensating chamber 38 then presses the valve housing 15 in the
direction toward the pump chamber 18.
During the suction stroke of piston 12 in the direction of the
arrow x.sub.1 the suction valve 28 will be opened against the
action of spring 34, while the pressure valve 23 will be firmly
pressed upon its valve seat 24 by the pressure of the pressure
medium which is contained in valve chamber 19 and by the pressure
of spring 34. The pressure medium, especially a liquid, will then
be drawn from the suction line 33 through the valve channels 29
into the pump chamber 18. This pump chamber 18 including the
grooves 27 in valve shaft 25, the transverse bores 37 and the
compensating chamber 38 will then be under a suction pressure,
while the pressure-valve chamber 19 will be under a high pressure.
The pressure medium contained in valve chamber 19 will then press
the valve housing 15 in the direction of the arrow x.sub.1, that
is, in the direction toward the pump chamber 18, so that shoulder
16 will be pressed against the corresponding shoulder of the pump
housing 10. The effective pressure surface of valve housing 15
which is then acted upon by the pressure medium in the
pressure-valve chamber 19 is indicated in FIG. 1 by the arrow
f.sub.1 and has a diameter d.sub.1.
During the following compression stroke of piston 12 in the
direction of the arrow x.sub.2 the suction valve 28 will be closed
and pressure valve 23 will be opened against the action of spring
34. The pump chamber 18, the grooves 27 in valve shaft 25, the
valve chamber 19 and the compensating chamber 38 will then be under
the full pump pressure. Since this pressure acts in one axial
direction upon valve housing 15 from the pressure-valve chamber 19
and from the compensating chamber 38 and in the other axial
direction from pump chamber 18, the opposing axial pressures will
balance each other with the exception of those axial pressures
which result from the difference between the diameter d.sub.2 of
the end surface f.sub.2 and the diameter d.sub.3 of the surface
f.sub.3 which corresponds to the diameter of bore 13, in which the
diameter d.sub.2 exceeds the diameter d.sub.3 by twice the value of
a.
In accordance with the invention, the respective parts are
preferably made of such dimensions that f.sub.2 - f.sub.3 = f.sub.1
or that
(.pi./4) .sup.. (d.sub.2.sup.2 - d.sub.3.sup.2) = (.pi./4)
d.sub.1.sup.2.
Since the differential surface area f.sub.2 - f.sub.3 equals the
surface area f.sub.1, the same pressure will be exerted upon the
valve housing 15 during the compression stroke from the valve
chamber 19 and the compensating chamber 38 as will be exerted
thereon during the suction stroke. The shoulder 16 of valve housing
15 will therefore always abut with the same pressure or at least
substantially the same pressure against the corresponding shoulder
of the pump housing 10. Alternating stresses will therefore be
avoided at this point which increases the durability of the valve
housing 15 considerably.
FIG. 1 further illustrates gaskets 39, 40, 41, 42 and 43 which seal
the pump chamber 18, the annular channel 32, the compensating
chamber 38 and the pressure-valve chamber 19 including the pressure
channel 20 relative to each other or toward the outside.
The present invention is not limited to the particular embodiment
thereof as previously described and illustrated in the drawings.
Thus, for example, in place of a valve housing another device may
be employed which may operate in a similar manner or be subjected
to similar stresses and the various channels or chambers may also
be arranged in a different manner relative to each other.
* * * * *