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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a check valve assembly for use in high
pressure pumps having check valve means controlling incoming and outgoing
fluid flow. The check valve assembly of the present invention is
especially suitable for use in reciprocating pumps or other pressure
chambers operating at fluid pressures in excess of 10,000 psi, and may be
adapted for use in many different types of reciprocating pumps or pressure
chambers, such as electrically or engine driven crankshaft pumps,
hydraulically driven fluid pressure intensifiers, and single or multiple
cylinder pumps of all sizes and capacities.
2. Description of the Prior Art
Check valve assemblies are critical components in high pressure pumps
because they control the flow of fluid into and out from the pressure
chamber which houses the reciprocating means. The reliability of check
valves is of paramount importance in the operation of high pressure pumps,
since any disruption of fluid flow results in disruption of pump
operation. Because existing check valves are mounted remote from a
pressure chamber such that the inlet and outlet passages and the check
valves are exposed to cycling high and low pressures, during intake and
compression strokes, check valves and both fluid passages are vulnerable
to cyclic stresses and fatigue.
Fluids may be pressurized to levels significantly in excess of 10,000 psi
in high pressure reciprocating pumps. Pressure intensifiers which are
known to the art are used to pressurize catalyst, water, and other fluids
to pressures in excess of 50,000 psi. These types of pumps operate at high
reciprocating rates, and the check valves are subject to tremendously high
frequency and pressure cyclic stresses. High pressure pumps having
multiple reciprocating means are also known to the art.
Inlet and outlet fluid passages located in valve bodies of commercially
available high pressure pumps typically have an "L" or a "T"
configuration. In an "L" configuration, inlet and outlet check valves
communicate by means of valve body fluid passages which are perpendicular
to each other. In a "T" arrangement, the inlet and outlet check valves are
arranged opposite one another on opposite terminal ends of a valve body
fluid passage represented by the top bar of the "T", while a second fluid
passage, represented by the vertical bar of the "T", perpendicular to the
inlet and outlet fluid passages provides communication between the
pressure chamber which houses the reciprocating means and the inlet and
outlet passages. In both of these existing arrangements, the inlet and
outlet fluid passages are provided in a massive valve body. The check
valves may be provided directly in the valve body, or they may be arranged
outside of the valve body in proximity to the inlet and outlet fluid
passages. High pressure pump manufacturers have also used check valve
assemblies having inlet and outlet fluid passages oriented in a "V"
arrangement, but material failure due to cyclic stresses from cycling high
and low pressures, particularly in the inlet and outlet fluid passages
have also been observed in crankshaft pumps and fluid intensifiers having
fluid passages arranged in a "V" configuration.
Inlet and outlet fluid passages in high pressure pumps having either an "L"
or a "T" arrangement are subjected to cyclic stresses imposed by forces
generated by alternating high and low pressures common to reciprocating
means. Sharp corners of the inlet and outlet passages are also subjected
to high stress concentrations which often result in material fatigue and
fracture. U.S. Pat. No. 4,026,322 teaches a reciprocating pump check valve
assembly wherein low pressure fluid inlet passages are arranged in an
angular, conical configuration terminating at the fluid inlet valve, and a
fluid outlet passage is coaxially aligned with the reciprocating means in
the pressure chamber. The fluid outlet passage of this check valve
assembly is not protected from cyclic stresses which originate in the
pressure chamber, and the fluid inlet check valve is too mechanically
complex to provide reliable service.
U.S. Pat. No. 2,666,448 teaches a self-sealing relief valve having a
helical spring mounted between a threaded nut and a valve member. The
spring keeps the valve member seated at all times except when relieving
excess pressure from within a container. U.S. Pat. No. 3,106,169 discloses
an intensifier high pressure valve and block assembly having an outlet
valve member which may be of a poppet valve type. U.S. Pat. No. 3,702,624
teaches a piston pump having an intake valve which is in the form of an
annular valve acted upon by a spring which presses the valve upon a seat
in a valve housing.
U.S. Pat. No. 3,565,191 discloses a rock-drilling apparatus having an
intensifier with a piston and check valves positioned in conduit means for
preventing and permitting flow of fluid. U.S. Pat. No. 3,540,349 teaches a
double-acting pressure booster having check valves mounted within pressure
lines. U.S. Pat. No. 3,070,023 discloses a fluid operated pump having
check valves arranged to permit fluid to flow from an enclosure to a
conduit.
U.S. Pat. No. 3,811,795 teaches a high pressure fluid intensifier having
control valves. U.S. Pat. No. 2,942,584 teaches a reversing valve for a
hydraulic reciprocating motor which has spaces on both sides of the motor
piston alternately connected to the supply and exhaust of a hydraulic
medium by means of a slide valve.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide a reliable check
valve assembly for use in high pressure pumps generating pressurized fluid
at pressures in excess of about 10,000 psi which experiences reduced
incidences of material fatigue and failure due to cyclic stresses caused
by cycling high and low pressure operation.
It is another objective of the present invention to provide a check valve
assembly which is suitable for use in a variety of high pressure pumps or
other pressure chambers, such as crankshaft pumps and fluid pressure
intensifiers, wherein inlet and outlet fluid passages are aligned
generally parallel to each other, and inlet and outlet check valves are
both positioned adjacent the pressure chamber which may house
reciprocating means.
It is yet another objective of the present invention to provide a check
valve assembly for high pressure pumps or other pressure chambers which is
suitable for use with multiple inlet and/or outlet fluid passages and
multiple inlet and/or outlet check valves.
The check valve assembly of the present invention comprises a valve body
having at least one low pressure fluid inlet passage and at least one high
pressure fluid outlet passage, each fluid passage having check valve means
positioned adjacent to the pressure chamber at the chamber end of each
fluid passage. Placement of the check valve means adjacent the pressure
chamber is an important aspect of this invention for such placement
protects the fluid passages from cyclic stresses due to the reciprocating
pump action, thus reducing incidences of material fatigue and failure in
the fluid passages of the check valve assembly. Placement of the check
valve means in proximity to the pressure chamber will expose each fluid
inlet passage to only a constant low pressure and each fluid outlet
passage to only a constant high pressure, thus eliminating exposure to
cycling high and low pressures within each passage.
According to a preferred embodiment of the check valve assembly of the
present invention, at least one low pressure fluid inlet passage is
aligned generally parallel to at least one fluid outlet passage.
Additionally, the check valve assembly of the present invention comprises
simplified one-way valve means which provide increased valve operating
life and reliability.
The check valve assembly of the present invention is suitable for high
pressure applications, and is particularly suitable for use with high
pressure reciprocating pumps or other pressure chambers producing or
containing pressurized fluid, particularly those fluids at pressures in
excess of 10,000 psi. The check valve assembly of the present invention is
suitable for use with a wide variety of high pressure reciprocating pumps
or other pressure chambers, and is especially suitable for use with motor
driven crankshaft pumps and double-acting pressure intensifiers.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features of the present invention will be apparent from the
following more detailed description read in conjunction with the following
drawings, in which:
FIG. 1 shows a partially sectional side view of a check valve assembly,
according to one embodiment of the present invention, mounted within a
pressure cylinder;
FIG. 2 shows a partially sectional side view of a check valve assembly,
according to one embodiment of the present invention, comprising multiple
low pressure inlet passages and inlet valve means mounted within a
pressure cylinder;
FIG. 3 shows a front view of a check valve assembly, according to one
embodiment of the present invention, as viewed from inside the pressure
chamber;
FIG. 4 shows a side view of a valve disk which is suitable for use in the
one-way valve means of the check valve assembly;
FIG. 5 shows a side view of a valve poppet which is suitable for use in
one-way valve means of the check valve assembly;
FIG. 6 shows a partially sectional side view of a check valve assembly,
according to one embodiment of the present invention, comprising multiple
low pressure fluid inlet passages in communication with an inlet fluid
manifold and a high pressure fluid outlet passage in communication with an
outlet fluid manifold;
FIG. 7 illustrates a motor driven triplex crankshaft pump suitable for use
with the check valve assembly of the present invention;
FIG. 8 illustrates a double-acting hydraulically driven pressure
intensifier utilizing the check valve assembly of the present invention,
FIG. 9 shows a partially sectional side view of an inlet valve arrangement
as show in FIGS. 2 and 3, with the section showing a retaining pin mounted
in a closed bore of the valve body.
DESCRIPTION OF PREFERRED EMBODIMENTS
As shown in FIG. 1, check valve assembly 10 is sealed and mounted in
pressure cylinder 40 in a fluid-tight manner with at least two one-way
valve means adjacent pressure chamber 41 wherein piston 45 reciprocates
along the central longitudinal axis of pressure cylinder 40. It is
apparent that check valve assembly 10 can also be mounted in any type of
pressure chamber such as a combustion engine block, pump housing, a
vessel, or the like. Low pressure fluid is supplied to check valve
assembly 10 through low pressure fluid inlet means 13, which is in
fluid-tight communication with low pressure fluid inlet passage 11 by
means of fluid inlet fitting 12. It is apparent that other types of
fittings or connections exist for connecting an inlet fluid source to
fluid inlet passage 11, such as a direct opening to a chamber, compression
fitting, and the like. In a similar fashion, high pressure fluid outlet
means 17 is in fluid-tight communication with high pressure fluid outlet
passage 15 by means of fluid outlet fitting 16.
According to the preferred embodiment shown in FIG. 1, low pressure fluid
inlet passage 11 is aligned generally parallel to high pressure fluid
outlet passage 15. Alternatively, inlet and outlet fluid passages may be
aligned at an angle to the central axis of valve body 14, and according to
this embodiment, inlet and outlet fluid passages are preferably arranged
symmetrically with respect to the central axis of valve body 14. Fluid
inlet and outlet fittings 12 and 16, respectively, may be threadedly
engaged with valve body 14, or they may be fluid-tightly sealed and
mounted in valve body 14 in other ways which are well known to the art.
Similarly, valve body 14 may be directly or indirectly threadedly engaged
with high pressure cylinder 40, or valve body 14 may be fluid-tightly
sealed and mounted on high pressure cylinder 40 by compression means or
other means known to the art.
Piston 45 reciprocates in pressure chamber 41 and, on alternate strokes,
draws fluid from low pressure fluid inlet passage 11 into pressure chamber
41 and discharges fluid from pressure chamber 41 through high pressure
fluid outlet passage 15. Valve body 14 comprises at least one inlet
one-way valve means and one outlet one-way valve means both adjacent
pressure chamber 41. In the embodiment of check valve assembly shown in
FIG. 1, the inlet valve means comprises inlet valve disk 20 having fluid
inlet passage 22 aligned with fluid inlet passage 11, inlet valve closure
means, shown as inlet valve ball 24 in a preferred embodiment, and inlet
valve spring 26. According to a preferred embodiment, inlet valve recess
21 may be provided in inlet valve disk 20 to accommodate and align inlet
valve spring 26, and replaceable inlet valve seat 25 may be provided
adjacent inlet valve ball 24. Inlet valve seat 25 may have chamfered edges
where inlet valve ball 24 or other inlet valve closure means contacts
inlet valve seat 25. In one embodiment, inlet valve seat 25 is an integral
part of valve body 14.
The outlet valve means comprises outlet valve fitting 30 mounted and sealed
in a fluid-tight manner in valve body 14, with enlarged head 36 projecting
into pressure fluid chamber 41, gasket seal ring 33, high pressure fluid
outlet passage 31 aligned with fluid outlet passage 15, outlet valve
closure means, shown as outlet valve ball 32 in a preferred embodiment,
and outlet valve spring 34. Inlet valve disk 20 is provided with outlet
valve aperture 23 through which outlet valve fitting 30 passes. Outlet
valve fitting 30 with enlarged head 36 aligns and holds inlet valve disk
20 against valve body 14. The opposite end of outlet valve fitting 30 may
have chamfered edges around the central fluid passage where outlet valve
ball 32 or other outlet valve closure means contacts with outlet valve
fitting 30. Static seal 19 is provided to prevent fluid leakage from
pressure chamber 41 between valve body 14 and high pressure cylinder 40.
During the power stroke of piston 45, the fluid pressure generated in
pressure chamber 41 and fluid outlet passage 31 displaces outlet valve
ball 32 against outlet valve spring 34, thus permitting the flow of fluid
through the one-way outlet valve into high pressure fluid outlet passage
15. Once the power stroke has ended, the tension of outlet valve spring 34
seats outlet valve ball 32 against outlet valve fitting 30, to prevent
fluid flow through high pressure fluid outlet passage 15. Gasket seal ring
33 is compressed by outlet valve fitting 30 against valve body 14 to form
a fluid-tight seal. In one embodiment, gasket seal ring 33 is an integral
part of outlet valve fitting 30.
The force generated by the intake stroke of piston 45 displaces inlet valve
ball 24 against inlet valve spring 26 and draws low pressure fluid through
low pressure fluid inlet passage 11 to pressure chamber 41. Once the power
stroke of piston 45 has been initiated, the inlet check valve is closed by
inlet valve ball 24 seating against inlet valve seat 25 or valve body 14.
In this fashion, the inlet and outlet check valves operate independently
from each other as one-way valves.
Piston 45 and pressure cylinder 40 are preferably generally cylindrical.
The elements of check valve assembly 10 comprise materials such as
stainless steel, carbon steel, plastics, and the like. Other suitable
component parts and materials of construction for the elements of check
valve assembly 10 are well known to the art. For example, valve disk 37
and valve poppet 38, as shown in FIGS. 4 and 5, respectively, are known to
the art for use in check valves and can be used in lieu of inlet valve
ball 24 and/or outlet valve ball 32 in the check valve assembly of the
present invention. Valve disk means 37 and valve poppet means 38 would
normally be used in applications where high flow rates require ample fluid
passage and valve balls may create problems with inertia effects. All of
the fluid passages, seals, fittings, and connections of the check valve
assembly must be capable of withstanding the forces generated by high
pressure pump operation.
FIG. 2 illustrates an embodiment of check valve assembly 10 having multiple
low pressure fluid inlet passages. In this embodiment, valve body 14 is
indirectly mounted in pressure cylinder 40 by means of threaded collar 42.
Valve body 14 is provided with flange 18 which is larger in diameter than
the interior of pressure cylinder 40, and which serves as an attachment
flange for collar 42. One important feature of the check valve assembly of
the present invention is that regardless of the number or arrangement of
inlet and outlet fluid passages, both inlet and outlet check valves are in
proximity to pressure fluid chamber 41.
As shown in FIG. 2, each low pressure fluid inlet passage is provided with
a one-way check valve means mounted adjacent pressure chamber 41 to
protect the fluid inlet passages from cyclic stresses due to high
reciprocating rates of piston 45. According to a preferred embodiment, low
pressure fluid inlet passages 11 are aligned substantially parallel to
high pressure fluid outlet passage 15, with fluid outlet passage 15
aligned with the central longitudinal axis of valve body 14, and multiple
fluid inlet passages 11 arranged symmetrically and radially with respect
to fluid outlet passage 15. Outlet valve fitting 30 is fluid-tightly
sealed and mounted in valve body 14 with central fluid passage 31 aligned
with high pressure fluid outlet passage 15, and outlet valve aperture 23
of inlet valve disk 20 is centrally arranged to accommodate outlet valve
fitting 30. Inlet valve disk 20 is provided with a plurality of fluid
inlet passages 21 corresponding in configuration and arrangement to low
pressure fluid inlet passages 11, and is preferably provided with a
plurality of inlet valve recesses 21 sized to retain inlet valve balls 24.
A single inlet valve spring 26 is provided between enlarged head 36 of
outlet valve fitting 30 and inlet valve disk 20. During the intake stroke
of piston 45, inlet valve disk 20 is forced against and compresses inlet
valve spring 26 to permit fluid to flow from fluid inlet passages 11 into
pressure chamber 41. Upon commencement of the power stroke of piston 45,
inlet valve disk 20 is forced toward valve body 14 and inlet valve balls
24 fluid-tightly seal low pressure fluid inlet passages 11. The outlet
check valve means operates as described above with reference to FIG. 1.
FIG. 3 shows an end view of check valve assembly 10 having multiple fluid
inlet passages arranged symmetrically with respect to a single high
pressure fluid outlet passage. FIG. 3 also shows retaining pin 35 which
extends from inlet valve disk 20 and is engaged in a corresponding or
mating hole in valve body 14 to prevent rotation of inlet valve disk 20.
FIG. 9 shows retaining pin 35 mounted within closed bore 39 of valve body
14. It is apparent that a plurality of retaining pins 35 can be used to
prevent rotation of inlet valve disk 20. FIG. 3 illustrates a preferred
embodiment of check valve assembly 10 having four low pressure fluid inlet
passages and four inlet check valve means arranged radially and
symmetrically with respect to the high pressure fluid outlet passage. Any
number of low pressure fluid inlet passages, preferably from one to about
eight may be provided for fluid supply to pressure fluid chamber 41, and
any number of high pressure fluid outlet passages may also be provided.
Although the drawings illustrate a single high pressure fluid outlet
passage, and this embodiment is preferred for most applications, multiple
high pressure fluid outlet passages may be provided and preferred for
certain applications.
FIG. 6 shows fluid inlet and outlet manifolds mounted on the check valve
assembly of FIG. 2. Fluid inlet manifold 55 is provided with low pressure
fluid inlet means 57 providing low pressure fluid to inlet fluid passages
11 in valve body 14. Low pressure fluid inlet manifold 55 abuts flange 18
of valve body 14 and is fluid-tightly sealed against valve body 14 by tie
rods 58 and sealing elements 56. Fluid inlet manifold 55 is provided with
bores accommodating tie rods 58, which are retained in inlet fluid
manifold 55 by means of enlarged tie rod nuts 59. High pressure fluid
outlet manifold 50 is mounted on inlet fluid manifold 55 by means of tie
down bolts 51, and is provided with high pressure fluid outlet 52 in
fluid-tight communication with fluid outlet passage 15. According to a
preferred embodiment of the check valve assembly of the present invention
for use with an inlet and outlet manifold, valve body 14 is provided with
a central extension 28 and fluid outlet manifold 50 is provided with a
corresponding recess to permit, with the aid of sealing elements 29,
fluid-tight connection of fluid outlet manifold 50 to valve body 14.
FIG. 7 shows motor-driven triplex crankshaft pump 60 suitable for use with
the check valve assembly of the present invention. Crankshaft 62 is driven
by driving means 65, such as an electric motor or engine and is mounted in
housing 61 by means of crankshaft bearings 64. Crankshaft 62 drives
pistons 66 which are attached to connecting rods 67 that drive plungers
45. Tie rods 58 penetrate pump housing 61 and are rigidly engaged with
fluid inlet manifold 55. Pressure cylinders 40 extend between pump housing
61 and fluid inlet manifold 55, and a check valve assembly 10 is provided
at the intersection of each pressure cylinder 40 with fluid inlet manifold
55 and fluid outlet manifold 50, as shown in FIG. 6. Low pressure fluid
inlet means 54 provides low pressure fluid to fluid inlet manifold 55, and
high pressure fluid outlet means 49 is provided as a conduit for high
pressure fluid exiting through fluid outlet manifold 50. A high pressure
crankshaft pump of this type may be provided with multiple pistons,
multiple high pressure plungers, and the like, and preferably provides
fluid having a pressure in excess of 10,000 psi.
FIG. 8 illustrates another application for the check valve assembly of the
present invention, in double-acting, hydraulically driven pressure
intensifier 70. Check valve assemblies 10 are mounted at opposite ends of
pressure cylinders 40 by means of compression collars 42. Each of two high
pressure plungers 45 is attached to reciprocating piston 75, which
reciprocates between first low pressure chamber 71 and second low pressure
chamber 73 in working fluid chamber 76. The operating principles of
double-acting fluid pressure intensifiers are well known to the art, and
variations of the embodiment shown in FIG. 8 are suitable for use with the
check valve assembly of the present invention. The introduction of
pressurized hydraulic working fluid into first and second low pressure
chambers 71 and 73, respectively, is controlled by four-way valve control
means 81. Four-way valve control means 81, according to a preferred
embodiment, is in communication with proximity sensors 80, which detect
the location of reciprocating piston 75. As piston 75 is reciprocated in
working fluid chamber 76 by the controlled introduction of pressurized
working fluid, force is alternately transmitted to high pressure plungers
45 to alternately pressurize fluid introduced into first high pressure
chamber 72 and second high pressure chamber 74 by means of check valve
assemblies 10. Since the force transmitted to fluid in first and second
high pressure chambers 72 and 74, respectively, is the product of the
pressure of the working fluid and the surface area of the high pressure
plunger, fluid in high pressure chambers 72 and 74 may attain pressures
considerably higher than the working fluid introduced into working fluid
chamber 76. The "intensification factor" of pumps of this type is
determined by the pressure of the working fluid, the cross-sectional
surface area of the reciprocating piston in the working fluid chamber, and
the cross-sectional surface area of the high pressure plungers.
Intensification factors of up to and greater than 20 may be attained in
hydraulically driven pressure intensifier pumps of this type, so that
working fluid at a pressure of about 5,000 psi may be used to generate
fluid pressures of up to about 100,000 psi.
While in the foregoing specification this invention has been described in
relation to certain preferred embodiments thereof, and many details have
been set forth for purposes of illustration, it will be apparent to those
skilled in the art that the invention is susceptible to additional
embodiments and that certain of the details described herein may be varied
considerably without departing from the basic principles of the invention.
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