Pump housing with multiple discharge valves

Abstract

A plunger pump fluid end housing assembly comprising: a fluid end housing, multiple plungers a single suction valve and seat corresponding with each said plunger, and one or more discharge valves and seats corresponding with each said plunger; wherein axes of said suction valve and seat are parallel with said plunger, the axes of said discharge valves and seats are substantially parallel to each other and perpendicular to the said plunger axis, and the suction manifold is positioned to feed the fluid chamber opposite the power end of the fluid end.

Description

FIELD OF THE INVENTION

The invention relates generally to high-pressure plunger pumps used, for example, in oil field operations. More particularly, the invention relates to an internal bore configuration that improves flow, improves cylinder filling, and incorporates structural features for stress-relief in high-pressure plunger pumps.

BACKGROUND

Engineers typically design high-pressure oil field plunger pumps in two sections; the (proximal) power section and the (distal) fluid section. The power section usually comprises a crankshaft, reduction gears, bearings, connecting rods, crossheads, crosshead extension rods, etc. Commonly used fluid sections usually comprise a plunger pump fluid end housing with multiple fluid chambers, each chamber having a suction valve in a suction bore, a discharge valve in a discharge bore, an access bore, and a plunger in a plunger bore, plus high-pressure seals, retainers, etc. FIG. 1 is a cross-sectional schematic view of a typical fluid end housing fluid chamber showing its connection to a power section by stay rods. A plurality of fluid chambers similar to that illustrated in FIG. 1 may be combined, as suggested in the Triplex fluid section housing schematically illustrated in FIG. 2.

Valve terminology varies according to the industry (e.g., pipeline or oil field service) in which the valve is used. In some applications, the term “valve” means just the moving element or valve body. In the present application, however, the term “valve” includes other components in addition to the valve body (e.g., various valve guides to control the motion of the valve body, the valve seat, and/or one or more valve springs that tend to hold the valve closed, with the valve body reversibly sealed against the valve seat).

Each individual bore in a plunger pump fluid end housing is subject to fatigue due to alternating high and low pressures that occur with each stroke of the plunger cycle. Conventional fluid end housings, also referred to as cross-bore blocks, typically fail due to fatigue cracks in one of the areas defined by the intersecting suction, plunger, access and discharge bores as schematically illustrated in FIG. 3A.

To reduce the likelihood of fatigue cracking in the high-pressure plunger pump fluid end housings described above, a Y-block housing design has been proposed. The Y-block design, which is schematically illustrated in FIG. 4, reduces stress concentrations in a plunger pump housing such as that shown in FIG. 3A by increasing the angles of bore intersections above 90°. In the illustrated example of FIG. 4, the bore intersection angles are approximately 120°. A more complete cross-sectional view of a Y-block plunger pump fluid end housing is schematically illustrated in FIG. 5.

Both cross-bore blocks and Y-blocks have several major disadvantages when used to pump heavy slurry fluids as typically utilized in oilfield fracturing service. A first disadvantage is related to the feeding of the plunger bore cavity on the suction stroke of the pump. Upon passing through the suction valve, the fluid must make a 90 degree turn in a cross-bore housing, or a 60 degree turn in a Y-block housing, into the plunger bore as illustrated in FIG. 6. This change in the direction of the heavy fluid robs the fluid of kinetic energy, hereafter referred to as fluid energy.

Fluid energy is normally added to the fluid by small supercharging pumps upstream from the plunger pump. Fluid energy is necessary to overcome fluid inertia and ensure complete filling of the inner pump cavity or volume on the suction stroke. If the fluid could possibly enter the housing inner cavity or volume in a linear or straight path, less fluid energy would be lost.

The second disadvantage of cross-bore blocks and Y-blocks relates to the large intersecting curved areas where the various bores intersect. Because the suction bore above the suction valve is almost as large as the plunger bore, the intersection area of the suction bore with the plunger bore is particularly large as illustrated in FIGS. 3A and 3B. While the intersection of the suction bore and the plunger bore is notably large, the intersection of the discharge bore and the plunger bore is almost as large.

As shown in FIGS. 7a and 7B, the intersecting cylindrical sections result in intersection curves that focus or concentrate the stresses generated by the internal pump pressures into a very small area. This small area is located at the bore intersection near the plane formed by the axis of the plunger and suction or discharge bore cylinders at the finite point of the intersection of the two cylinders. Because the intersection curve changes slope through three-dimensional space, this intersection cannot be easily chamfered or filleted by conventional machining techniques that would mitigate these stresses to a smaller extent. Indeed, complex computer finite element stress analysis calculations indicate that chamfering or filleting the corner intersection has minimal effect on reducing the stresses at this corner intersection.

The amount of stress at the intersecting bores of conventional fluid end housings is defined by the magnitude of the “Bore Intersection Pitch” as illustrated in FIGS. 3A, 3B, and 4. Any geometry that reduces the “Bore Intersection Pitch” will reduce the stress concentrations in the fluid end and increase the life of the fluid end by mitigating cyclic fatigue failure. Y-Block fluid, such as those illustrated in FIG. 4, end housing designs do reduce this pitch, but the reduction is insufficient to prevent cyclic fatigue failure of the fluid end housing when subjected to high pressure and long pumping cycles.

SUMMARY OF THE INVENTION

The fluid end housing of the present invention comprises multiple fluid chambers with each chamber having a suction bore that is aligned with the plunger bore, commonly referred to as an “in-line configuration,” i.e., the bores are aligned. As such, the axis of the suction bore is substantially co-linear with the plunger bore. The configuration of the suction bore of the present invention eliminates the loss of fluid energy present in fluid end housings of the prior art in which the suction fluid flow must undergo a right angle turn to fill the plunger bore or inner cavity of the housing.

The fluid chamber of the housing of the present invention also comprises multiple discharge valves and seats. In one embodiment, two discharge valves and seats are included in the assembly. In this embodiment, each valve is approximately half the size of the suction valve such that the combined flow capacity of the two discharge valves approximately equals the flow capacity of the single suction valve. In this embodiment, the bores of said discharge valves are arranged opposite of each other and perpendicular to the plunger bore centerline. In this embodiment of the invention, the discharge ports connecting the plunger chamber with the discharge valves and seats are less than half the size of the plunger bore; thus the intersection area of the discharge bore with the plunger bore is significantly smaller than the intersection area of the suction bore with the plunger bore of conventional housings of the prior art. Because the plunger bore of the present invention is many times larger than the discharge bore, the bore intersection pitch and the convergence of stress is markedly reduced. Accordingly, in the embodiments of the present invention, the peak stress at the bore intersection is less than 20% of the stress of conventional housings of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional schematic view of a typical prior art plunger pump fluid section showing its connection to a power section by stay rods.

FIG. 2 schematically illustrates a conventional prior art Triplex plunger pump fluid section housing.

FIG. 3A is a cross-sectional schematic view of suction, plunger, access and discharge bores of a conventional prior art plunger pump housing intersecting at right angles and showing areas of elevated stress and the “Bore Intersection Pitch.”

FIG. 3B schematically illustrates the sectional view labeled B-B in FIG. 3A.

FIG. 4 is a cross-sectional schematic view of suction, plunger and discharge bores of a prior art Y-block plunger pump housing intersecting at obtuse angles showing areas of elevated stress and the “Bore Intersection Pitch.”

FIG. 5 is a cross-sectional schematic view similar to that in FIG. 4, including internal plunger pump components of a prior art Y-block fluid section.

FIG. 6 schematically illustrates a cross-section of a prior art right-angular plunger pump with valves, plunger, and a suction valve spring retainer showing the flow around the suction valve and the turn of the fluid into the plunger bore.

FIG. 7A schematically illustrates a three dimensional cross-section of one cylinder of a prior art right-angular plunger pump.

FIG. 7B schematically illustrates the enlarged sectional view labeled B-B in FIG. 7A highlighting the convergence of the stress at the intersection bores.

FIG. 8 schematically illustrates a cross-section of the fluid end housing assembly of the present invention showing its connection to a power section by stay rods.

FIG. 9A schematically illustrates a cross-section of the fluid end housing assembly of the present invention including detailed cross sections of the components of the assembly.

FIG. 9B schematically illustrates the sectional view labeled B-B in FIG. 9A.

FIG. 9C schematically illustrates the enlarged section labeled C-C in FIG. 9B.

FIG. 10A schematically illustrates a cross-section of the fluid end housing of the present invention

FIG. 10B schematically illustrates the sectional view labeled B-B in FIG. 10A.

FIG. 10C schematically illustrates the sectional view labeled C-C in FIG. 10B.

FIG. 11A schematically illustrates an orthogonal view of the suction valve spring retainer/plunger spacer.

FIG. 11B schematically illustrates an end view of the suction valve spring retainer/plunger spacer.

FIG. 11C schematically illustrates the section view labeled C-C of the suction valve spring retainer/plunger spacer of FIG. 11B.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 8 schematically illustrates a cross-section of an embodiment of the fluid end housing assembly 100 of the present invention showing its connection to a power section by stay rods. As opposed to fluid end housing of the prior art as illustrated in FIG. 1, fluid end housing 1 of the present invention is configured with the suction manifold 5 mounted in a position on the fluid end housing opposite the power end of the pump.

The housing 1 of the present invention features multiple fluid chambers 2 with each chamber 2 containing multiple bores. The plunger 310 may be of a two-piece design as illustrated in FIG. 8 with a plunger pressure end 311 and a plunger clamp end 312. A two-piece plunger facilitates easier maintenance by field mechanics. Alternately a one-piece plunger, not shown, could be utilized. However a one-piece plunger would require removal of the fluid end housing assembly 100 from the power end assembly for routine maintenance on components of assembly 100.

FIG. 9A schematically illustrates a cross-section of the fluid end housing assembly 100 of the present invention showing the major internal components of the assembly 100 including a fluid end housing 1 featuring multiple fluid chambers 2 with each chamber containing multiple internal bores 10, 20, 30, and 40. Major internal components of the assembly 100 arranged in the plunger bore 30 of housing 1 include the plunger 311, plunger packing 361, plunger packing gland nut 351, and suction valve spring retainer/plunger spacer 330. The suction bore 10, opposite to the plunger bore 30, contains the suction seat 112, suction valve 114, suction valve spring 115, suction valve guide 328 and suction valve spring retainer 326. Suction valve guide 328 and suction valve spring retainer 326 are integral to the suction valve spring retainer/plunger spacer 330. The centerlines of the suction bore 10, suction seat 112, suction valve 114, suction valve spring 115, the plunger bore 30, plunger 311, plunger packing 361, and the plunger packing gland nut 351 are all substantially co-linear. The co-linear arrangement of the plunger bore 30 and the suction bore 10 eliminates the concentration of stresses at the intersection these two bores typical of fluid end housings of the prior art as shown in FIGS. 3A, 3B, 4, 7A, and 7B.

FIG. 9A schematically further illustrates the components in the upper and lower discharge bores 20 and 40, respectively. Upper discharge bore 20 and lower discharge bore 40 connect with upper discharge manifold 28 and lower discharge bore 48, respectively, which are joined externally to the fluid end housing assembly 100 and the fluid end housing 1. Upper discharge bore 20 contains an upper discharge seat 212, upper discharge valve 214, upper discharge valve spring 215, upper discharge cover 216, and upper discharge cover retainer 217. Lower discharge bore 40 contains a lower discharge seat 412, lower discharge valve 414, lower discharge valve spring 415, lower discharge cover 416, and lower discharge cover retainer 417.

FIG. 9B schematically Section B-B of FIG. 9A. FIG. 9C illustrates enlarged Section C-C of FIG. 9B. Suction valve guide 328 and suction valve spring retainer 326 are integral to the suction valve spring retainer/plunger spacer 330. Shoulder 337 and cylindrical surface 332 of flange 333 on suction valve spring retainer/plunger spacer 330 mates with shoulder 37 and plunger packing bore 32 of housing 1, respectively. Central section 335 of suction valve spring retainer/plunger spacer 330 connects flange 333 with suction valve spring retainer 326. Central plunger chamber 34 positions central section 335 of suction valve spring retainer/plunger spacer 330. Plunger 311 reciprocates back and forth through the plunger packing 361 and inner surface 331 of suction valve spring retainer/plunger spacer 330. The centerlines of the suction bore 10, suction seat 112, suction valve 114, suction valve spring 115, plunger bore 30, plunger 311, plunger packing 361, and plunger packing gland nut 351 are all substantially co-linear.

FIG. 10A is an illustration of the fluid end housing 1 showing plunger bore 30, suction bore 10, upper discharge bore 20, and lower discharge bore 40 without the various other internal components shown in FIGS. 8 and 9A-C. Plunger bore 30 contains a packing bore 32 for holding plunger packing 361 and outer surface 332 of flange 333 of suction valve spring retainer/plunger spacer 330. Packing bore 30 also contains a plunger packing gland nut bore 35 for positioning of the plunger packing gland nut 351. Packing bore 32 is separated from the central plunger chamber 34 by a packing shoulder 37 which mates with a shoulder 337 on suction valve spring retainer/plunger spacer 330 as shown in FIGS. 11B and 11C. Plunger packing bore 32 also mates with the cylindrical section 332 of the flange 333 of suction valve spring retainer/plunger spacer 330 as illustrated in FIGS. 9 and 11B. Central section 335 of suction valve spring retainer/plunger spacer 330 is co-linear with central plunger chamber 34 of plunger bore 30.

Suction bore 10 as illustrated in FIG. 10A contains a suction seat bore 12 that captures suction seat 112 and a suction valve bore 14 in which suction valve 114 controls fluid flow. Suction valve bore 14 also holds suction valve spring 115, suction valve spring retainer 326, and upper suction valve guide 328. Immediately adjacent to the suction seat bore 12 is suction port 11 that connects the suction seat 112 and suction valve 114 with the suction manifold 5 as illustrated in FIG. 8.

FIG. 10B schematically illustrates Section B-B of FIG. 10A. FIG. 10C illustrates Section C-C of FIG. 10B. Upper discharge bore 20 of fluid end housing 1 contains a discharge seat bore 22 that captures the discharge seat 212 as shown in FIG. 9A. Immediately adjacent to the discharge seat bore 22 is upper discharge port 21 that connects the upper discharge seat 212 and upper discharge valve 214 with plunger chamber 34 at the bore intersection 25. Upper discharge bore 20 of fluid end housing 1 also contains an upper discharge cover bore 26 and an upper discharge cover retainer bore 27 that mate with upper discharge cover 216 and upper discharge cover retainer 217, respectively. Upper discharge valve bore 24 allows fluid passage from upper discharge seat 212 around upper discharge valve 214 and into upper discharge manifold 28 as illustrated in FIGS. 9A and 10A.

Lower discharge bore 40 of fluid end housing 1 contains a lower discharge seat bore 42 that captures the lower discharge seat 412 as shown in FIG. 9A. Immediately adjacent to the lower discharge seat bore 42 is lower discharge port 41 that connects the lower discharge seat 412 and lower discharge valve 414 with plunger chamber 34 at the bore intersection 45. Lower discharge bore 40 of fluid end housing 1 also contains a lower discharge cover bore 46 and a lower discharge cover retainer bore 47 that mate with lower discharge cover 416 and lower discharge cover retainer 417, respectively. Lower discharge valve bore 44 allows fluid passage from lower discharge seat 412 around lower discharge valve 414 and into lower discharge manifold 48 as illustrated in FIGS. 9A and 10A. Upper discharge manifold 28 and lower discharge manifold 48 connect externally to the fluid end housing 1.

FIGS. 11A, 11B, and 11C schematically illustrate the suction valve spring retainer/plunger spacer 330. FIG. 11A illustrates an end orthogonal view of the suction valve spring retainer/plunger spacer 330. FIG. 11B schematically illustrates an end view of the suction valve spring retainer/plunger spacer 330. FIG. 11C schematically illustrates the section view labeled C-C of the suction valve spring retainer/plunger spacer 330 of FIG. 11B. Suction valve spring retainer/plunger spacer 330 is constructed with a flange 333, a central section 335, a suction valve spring retainer 326 and a suction valve guide 328. Flange section 333 has a substantially cylindrical outside surface 332 and a shoulder 337 that mate with packing bore 32 and shoulder 37 of fluid end housing 1, respectively, as shown in FIGS. 9B and 9C.

Central section 335 has a substantially cylindrically inside surface 331 that it shares with flange 333. The diameter of cylindrical inner surface 331 is slightly greater than diameter of plunger 311 to allow plunger 311 to reciprocate freely within the suction valve spring retainer/plunger spacer 330. Exterior surface 334 of central section 335 of the suction valve spring retainer/plunger spacer 330 mates with plunger chamber 34 of fluid end housing 1.

Central section 335 has two opposing ports 320 and 340 that align with ports 21 and 41 in fluid end housing 1. The spring retainer section 326 is designed for the purpose of positioning and retaining the suction valve spring 115. Spring retainer section 326 connects with central section 335 via webs 395, 396, 397, and 398. Ports 314, 315, 316, and 317 allow passage for pumped fluid from the suction valve 114 to the interior of central section 335 of the suction valve spring retainer/plunger spacer 330.

Claims

1. A plunger pump fluid end housing with multiple fluid chambers arranged in a longitudinal plane and each fluid chamber comprising:

a suction bore;

a plunger bore;

a plurality of discharge bores;

wherein the axis of said suction bore and the axis of said plunger bore are parallel, and

wherein the axis of each individual discharge bore in said plurality of discharge bores is parallel to the axes of the other individual discharge bores in said plurality of discharge bores and also is substantially perpendicular to said suction bore axis.

2. A plunger pump fluid end housing of claim 1 wherein each fluid chamber contains two discharge bores.

3. A plunger pump fluid end housing of claim 1 wherein the axis of said plunger bore is substantially collinear with the axis of said suction bore.

4. A plunger pump fluid end housing of claim 1 wherein the area of either discharge port in said discharge bore equals approximately half the area of the suction port in said suction bore.

5. A plunger pump fluid end housing of claim 1 wherein the axes of the said individual discharge bores within said plurality of discharge bores are substantially collinear.

6. A plunger pump fluid end housing of claim 1 wherein the suction manifold ports of said housing are positioned on the fluid end housing opposite to the power end of the plunger pump.

7. A plunger pump fluid end housing assembly comprising:

a fluid end housing;

a plurality of plungers;

a single suction valve and seat corresponding to each individual plunger in said plurality of plungers;

a plurality of discharge valves and seats corresponding to each individual plunger in said plurality of plungers;

wherein the axis of each said suction valve and seat is parallel to each of said individual plungers in said plurality of plungers; and

wherein the axes of each of the individual discharge valves in said plurality of discharge valves and seats is parallel and substantially perpendicular to the respective axis of each of the said individual plungers, suction valves, and suction seats.

8. A plunger pump fluid end housing of claim 7, wherein each fluid chamber contains two discharge valves and two discharge seats.

9. A plunger pump fluid end housing assembly of claim 8, wherein each axis of said individual plungers is substantially collinear with the corresponding axis each of said individual suction valves and corresponding individual valve seats.

10. A plunger pump fluid end housing assembly of claim 7, wherein the flow area of either discharge seat of said assembly equals approximately half the flow area of said suction seat in said housing.

11. A plunger pump fluid end housing of claim 7, wherein the axes of said multiple discharge valves and seats are substantially collinear.

12. A plunger pump fluid end housing of claim 7, wherein the suction manifold of said housing assembly is positioned opposite to the power end of the plunger pump.