High pressure pump fluid end

Abstract

A new and improved fluid end for a high pressure pump, wherein the valves are assembled with a valve seat unit to form a readily removable and replaceable valve cartridge, and wherein the packing around the pump plunger is also readily accessible for replacement or repacking without requiring special tools. Peak pressures developed by the pump plunger, particularly during cavitation, are transmitted to the valve seat unit and the pump plunger packing rather than the much more expensive pump manifold so that if failure occurs due to such high pressures, the failure is in the readily replaceable and less expensive valve seat and pump packing.

Description

BACKGROUND OF THE INVENTION

The field of this invention is high pressure pumps, fluid end.

In high pressure pumps heretofore known and in common use today, they have been so constructed that disassembly, repair and replacement have been difficult and expensive. Repairs in the field have been a particular problem because of the need for special tools and the difficulties of disassembly and reassembly.

SUMMARY OF THE INVENTION

The present invention relates to a new and improved fluid end for a high pressure pump, wherein a valve cartridge having the valve seats and valves is subjected to peak pressures developed by the plunger, especially during cavitation, rather than the pump manifold, whereby the less expensive and easily replaceable parts of the pump are the ones subject to failure at such peak pressures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the fluid end of a high pressure pump, showing the improvements of this invention; and

FIG. 2 is a partial view taken on line 2--2 of FIG. 1, illustrating further details of the pump fluid end of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawings, the numeral 10 refers generally to the pump manifold block which is disposed adjacent to a pump cylinder 12. The cylinder 12 has a stuffing box 14 therewith through which a conventional pump plunger or piston 16 moves in response to a power supplied through a typical cross head 17, a portion of which is illustrated, and which is connected to a conventional power source in the known manner for reciprocating the plunger 16. As will be explained more in detail, the present invention includes a valve cartridge 30 which is disposed with the manifold 10, but which is removable thereform as a unit so that all of the valve components and valve seats may be removed readily from the rest of the parts to effect repairs and/or replacements. Also, the stuffing box 14 is readily removable for access to the packing 15 therewith so that such packing can be replaced or repaired.

Considering the invention more in detail, the manifold block 10 is mounted in a fixed position and has a section inlet opening or manifold 10a therethrough for the supply of fluid being pumped. Also, the manifold block 10 has an outlet discharge manifold or opening 10b for the discharge of fluid being pumped with the plunger 16, as will be more evident hereinafter. The inlet opening 10a connects with a valve cartridge recess or cavity 10c by means of one or more openings 10d. Similarly, the outlet manifold 10b connects with such cavity 10c by an opening 10e.

The manifold block 10 is positioned adjacent the pump cylinder 12, with a gasket 22 of any suitable gasket material therebetween to prevent fluid from escaping. The manifold block 10 has a plurality of bolt holes 10f, each of which is adapted to receive a bolt 23 having a conventional bolt head 23a with wrench flats thereon so that the bolts 23 may be rotated with a conventional wrench. Each bolt 23 has a threaded inner end 23b which is adapted to be releasably threaded into internally threaded openings 12a in the cylinder 12, which correspond in number and in location to the openings 10f in the block 10. Thus, by unthreading the bolts 23 so as to disengage the threads 23b from the threaded openings 12a, the cylinder 12 is released from its secured position with the block 10 and may be pulled away from the block 10, as will be more evident hereinafter.

A valve cartridge 30 is disposed within the valve cartridge recess 10c of the manifold block 10 and it includes at least two valves 33 and 35. The valve 33 is mounted in a valve passage 30a for movement therein and it seats upon an annular valve seat 30b which preferably has a spherical shape in cross-section to conform with a corresponding surface on the valve 33 for effective closing of fluid flow through the passage 30a when the valve 33 is in the seated position.

The valve 33 may be made in numerous ways, but as illustrated in the drawings, it includes a valve body 33a, with a plurality of valve guide ribs 33b disposed therewith and extending into the opening 30a. Such ribs 33b are preferably arranged in the form of a cross and they permit fluid flow therebetween so that when the valve body 33 is unseated from the seat 30b, fluid may flow past the valve 33.

The valve 33 has a valve stem 33c which receives a spring 36 disposed between the body 33a and a surface 12b of a cylinder recess 12c. The spring 36 is a relatively light spring and acts to keep the valve 33 seated when the fluid pressures are essentially balanced across the valve 33 and it prevents the opening of the valve 33 until a predetermined pressure is developed to unseat the valve 33.

The valve 35 is constructed in almost an identical manner to the valve 33, although it is slightly smaller in diameter and it includes a valve body 35a which is adapted to seat on an annular valve seat 30c in a valve opening 30d of the valve cartridge 30. The valve 35 has longitudinally extending guide ribs 35b (FIGS. 1 and 2), which, like the ribs 33b are preferably arranged in the form of a cross and which keep the valve 35 aligned during its reciprocating movement to and from its open and closed positions.

The valve 35 also has a spring guide stem 35c around which is positioned a spring 38 which serves to seat the valve 35 until a predetermined pressure urging it to an unseated position is acting on the valve 35.

It is to be noted that the valve 33 permits fluid flow from the suction inlet manifold 10a to the cylinder recess 12c and the plunger opening 12d within the cylinder 12 in which the plunger 16 reciprocates. During such flow, the valve 35 is retained in the seated or closed position. When the reverse occurs, and the plunger 16 moves towards the block 10, fluid is permitted to flow from the plunger opening 12d and the recess 12c to the outlet manifold 10b by opening the valve 35 and the valve 33 remains closed to prevent fluid from flowing out through the inlet opening 10a. Thus, each of the valves 33 and 35 is a oneway valve controlling the flow in the opposite direction.

A fluid seal is maintained between the valve cartridge 30 and the cylinder 12 by a seal 41, which may be brass, a rubber O-ring, or any suitable sealing material. Fluid seals 42 and 43 which also may be brass, rubber O-rings or suitable sealing members are provided for sealing engagement between the valve cartridge 30 and the wall of the valve cartridge recess 10c in the manifold block 10. Such seals 41-43 may be readily replaced as will be more evident hereinafter when the valve cartridge 30 is exposed and is removed for replacement and/or repair. Such seals 41-43 may all be formed of brass or any other suitable sealing material.

The packing 15 in the stuffing box 14 is preferably of the conventional chevron type and it has a lantern ring 15a between the sections of the chevron packing in the known manner. Such lantern ring 15a may be formed of brass or other suitable material. Also adapter rings 15b and 15c at each end of the chevron packings 15 are preferably utilized for confining the packing 15 and such rings 15b and 15c are likewise formed of brass or other suitable material. The packing 15 is thus confined in sealing engagement with the external polished surface of the plunger rod 16 and such sealing engagement is further enhanced by a spring or other resilient means 45 which is confined in engagement with the ring 15c and a shoulder 12e in the cylinder 12.

Grease is injected into the lantern ring area by means of a grease opening 14a and any conventional grease fitting 14b, as will be well understood. The stuffing box 14 has external threads 14c which are in threaded engagement with internal threads 12f in a counterbore 12g of the pump cylinder 12. The entire stuffing box 14 may thus be readily removed from the cylinder 11 by unthreading the threads 14c from the threads 12f. To lock the stuffing box 14 in the cylinder 12 during operation, a locking bolt 50 is preferably utilized and it extends through an opening 12h in the cylinder 12 and threads into a threaded section 12k and enters a shallow recess 14d in the stuffing box, whereby the stuffing box 14 is prevented from rotating or being rotated until the locking bolt 50 is unthreaded enough to come out of the recess 14d.

For the purpose of indicating to an operator when the seals around the valve cartridge 30 are leaking fluid, it is desirable to have a tell-tale hole 60 in the manifold block 10 extending to a point between the seals 40 and 42 so that in the event fluid is leaking therebetween, it will appear externally of the manifold block at the exit opening 60a of the tell-tale hole 60. At that point, the operator has an indication that the seals should be replaced before the leakage becomes serious.

In the operation or use of the pump fluid end of this invention, a plunger 16 is connected to a conventional cross head 17 as indicated in FIG. 1 and such cross head 17 is connected to a conventional prime mover or power source for reciprocating the plunger 16 within the cylinder 12 in the known manner.

The suction manifold 10a is connected to a source of fluid to be pumped in the known manner, and the outlet opening or manifold is preferably connected to a pipe or receptacle which is receiving the fluid being pumped.

When the pump plunger 16 moves away from the manifold 10, the suction stroke occurs and the fluid is drawn in to the plunger recess 12d by flowing through the open valve 33 from the suction or inlet manifold 10a to the recess 12c and the plunger opening 12d. At that time, the valve 35 is closed by the spring pressure of the spring 38 and by the reduced pressure internally of the recess 12c which is less than the fluid pressure on the other side of the valve 35.

The plunger 16 is moved towards the manifold block 10 on the pumping stroke so as to force the fluid through the valve 35 and out of the discharge manifold 10b. At that time, the valve 33 is closed. Thus, it will be seen that the fluid end pump illustrated in FIGS. 1 and 2 operates in a conventional manner by drawing in fluid on the suction stroke and discharging the fluid on the pump or pressure stroke. In the event it becomes desirable or necessary to replace or repair any part of the valve cartridge 30, or the seals therewith, the entire valve cartridge 30 may be readily exposed by unthreading the bolts 23 so as to disconnect the cylinder 12 from the manifold 10. Then by operating the pump plunger 16 so that it moves away from the manifold 10, it will carry with it the cylinder 12 and expose the valve cartridge 30. The valve cartridge 30 with its seals may be removed as a unit and replaced in its entirety in the field with a spare valve cartridge 30 and the seals. On the other hand, if such spare is not readily available, the worn parts can be repaired or replaced in part with conventional equipment and then the repaired or replacement valve cartridge 30 may be reinserted into the recess 10c and the cylinder 12 may be returned to its position adjacent the manifold block. When the bolts 23 are then reconnected as shown in FIG. 1, the pump is again ready for use. The disassembly and reassembly can thus be accomplished by the use of a wrench of an ordinary size and type capable of unthreading the bolts 23 so that no special tools are required for such operation.

The packing 15 may also be easily replaced and any of the parts therewith may be replaced or repaired at the same time. The entire stuffing box 14 may be disconnected from the cylinder 12 by releasing the locking action of the bolt 50 and then unthreading the stuffing box 14 from the cylinder 12 which exposes the entire bore of the stuffing box 14 so that the packing 15, the annular rings 15b and 15c and the lantern ring 15a can all be removed and replaced with new parts or repaired as necessary. The reassembly is carried out in the reverse by simply threading the stuffing box 14 back to the position shown in FIG. 1 and then inserting the locking bolt 50 to the locking position shown in FIG. 1. Again, no special tools are required for such operations.

Should cavitation occur when pumping, the presence of the air with the liquid results in a greater plunger velocity before impacting with the liquid, and as a result, higher peak pressures in the neighborhood of 20,000 p.s.i. and above are developed which have heretofore been exerted directly on the pump manifold, but in the present invention, the peak pressures are exerted on the valve cartridge 20 and the pump packing 15, so that if such peak pressures are high enough to cause failure, the failure occurs in the relatively inexpensive parts, namely, the cartridge 30 and/or the packing 15, rather than the very expensive manifold 10.

It should also be noted that the cylinder 12 and stuffing box 14 can be made in one-piece, in which case the packing 15 is replaced by releasing the bolts 23 from the threads 12a to expose the packing. A removable snap ring (not shown) would be used instead of the shoulder 12e to enable the spring 45 and the packing 15 to be removed for replacement.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

Claims

We claim:

1. A high pressure pump fluid end, comprising,

a manifold block having both an inlet suction manifold and an outlet discharge manifold located therein,

a pump cylinder mounted adjacent and perpendicular to said manifold block and having a plunger opening therein,

connector means releasably connecting said pump cylinder to said manifold block,

a pump plunger operably mounted in said pump cylinder for reciprocation in said opening,

said manifold block including a recessed valve cartridge cavity having communication with said inlet manifold, said outlet manifold and said plunger opening, said cavity being located at the interface between the block and the plunger opening, and being larger than the plunger opening and encompassing said plunger opening,

an integral replaceable generally oval valve cartridge disposed in said valve cartridge cavity and having a first valve means therein for permitting fluid flow from said inlet manifold into said plunger opening upon movement of said pump plunger in a direction away from said manifold block, and a second valve means therein for permitting fluid flow from said plunger opening to said outlet discharge manifold upon movement of said pump plunger in a direction towards said manifold block,

said first and second valve means comprising wing guided valves situated wholly within the cartridge, mounted side by side and parallel to the axis of the pump plunger,

said cartridge positioned between the plunger opening and said manifold block, and extending outwardly beyond the depth of the cavity, and

an oval seal mounted in a groove in the cartridge and encircling said plunger opening for sealing between said pump cylinder and said valve cartridge whereby fluid pumped by said pump plunger is caused to exert peak fluid pressure directly on said cartridge and peak fluid pressure is isolated from said manifold block.

2. The apparatus of claim 1 wherein said first and second valve means include spherically shaped valve seats and elements.

3. The apparatus of claim 1 including,

a second circular seal means between the cartridge and said block sealing about the inlet suction manifold, and

third seal circular means between the cartridge and the block sealing about the outlet discharge manifold.

4. The apparatus of claim 3 including a tell-tale leak detector hole extending through said manifold block to said cartridge between the manifold block and pump cylinder for allowing fluid to leak externally of said manifold block from said hole when one of said seal members is allowing fluid to leak.