Easily replaceable valve assembly for a high pressure pump

A valve assembly for use in high pressure pumps is designed for easy replacement for example in the suction inlet here for a high pressure pump. The design utilizes a combination of screw threads and a locking member to provide structural strength for the valve to be placed in and withdrawn from the inlet bore.

BACKGROUND OF INVENTION

1. Field of the Invention

This invention relates to high pressure fluid pumps and in particular to an arrangement for allowing easy access to and repair/replacement of suction valves located within the pump housing.

2. Description of Related Art

High pressure reciprocating piston pumps have been used in the oil industry for several purposes such as hydraulic fracturing, cementing, and other well treating processes. Typical pump assemblies are disclosed in U.S. Pat. No. 6,544,012 issued to Blaine. The pumps generally include a power end and a fluid end. The power end includes a power source and linkage for reciprocating a plurality of plungers within the fluid end of the pump. The fluid end includes a suction manifold, a plurality of intake or suction valves, a plurality of output valves and a discharge header. The fluid pressure within the pump chamber can be in excess of fifteen thousand psi and the fluid being pumped often contains abrasive materials such as sand. Consequently the valves are subject to extreme conditions which cause failures and require regular service and replacement. It is therefore desirable to construct the valve assembly so as to be easily accessible and replaceable in a short period of time.

Current methods for accessing the suction valves include providing a bore with a plug as shown in U.S. Pat. No. 7,681,589 at 38 and 40 in FIG. 1. Another method is disclosed by Blume in the above mentioned U.S. Pat. No. 6,544,012 that includes providing a threaded suction valve seat retainer 135. However in high pressure applications the threads on the valve seat retainer are not sufficient to withstand the force within the pump chamber.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes the above mentioned deficiencies in the prior art by providing a suction valve assembly that is modular in nature and is secured in place by using a dual locking arrangement that distributes forces delivered by the pumping system between a threaded valve seat collar and a locking ring, which includes a plurality of arcuate segments. The invention may be applied to a stem guided valve type suction valve or to a “crows feet” guide suction valve.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates a conventional fluid end10of a high pressure pump. The fluid end includes an inclined top surface20having a plurality of bores12for receiving outlet valve mechanisms which are not shown. Fluid end10has a planar front side11and a rear side13that is adapted to be bolted to the power end. Suitable bores14,15are provided for receiving threaded studs with nuts. A horizontally extending outlet passageway16is in fluid communication with each of the outlet chambers21of the pump as shown inFIG. 2. Fluid end10further includes a lower extending inclined portion19. A plurality of inlet ports22are located in portion19. Planar front side portion11externals vertically between inclined surfaces20and19when the pump is secured to a truck bed. The rear side13of the fluid end includes a plurality of bores23for receiving the pistons (not shown) which are driven by the power end of the pump. The arrangement of the pistons, the fluid inlet, and the fluid outlet is commonly referred to as the “Y” design for a frac pump as shown inFIG. 2. However, a “T” configuration as known in the art could also be used.

FIG. 2illustrates the interior details of a typical pump chamber including suction inlets22, outlet chamber21and outlet passageway16. Suction valves (not shown) are located within bores22and outlet valves not shown) are located in bores12. A plurality of bores23are adapted to receive the pump plungers which are driven by the power end of the pump.

A valve assembly according to an embodiment of the invention is illustrated inFIG. 3. The valve assembly51includes a threaded valve seat collar50, a valve stem guiding member35, a valve member39including a stem and an upper head44with a valve face42, a valve spring37held in place by a spring retaining member36such that the valve head44is biased against the valve seat41on the collar50. An annular ridge32about the collar50provides space for the inclusion of a plurality of locking elements74within an annular groove40formed within a suction inlet bore33.

Valve seat collar50is threaded at52so as to be threadly received in inlet bore33of fluid end31. Valve seat collar50includes a valve stem guiding member35which is supported by arms47that extend between the inner portion of the valve seat collar and valve stem guiding member35, seeFIG. 4. Valve seat collar50also includes a shoulder48and an annular ridge32that cooperates with the locking elements74to help secure the valve seat collar within the bore in a manner to be discussed below. A spring37which may be a coil spring is disposed between a shoulder46on the valve stem guide35and a shoulder38provided on spring retaining member36. A locking pin not shown holds spring retaining member36on valve stem39. Member36could also be threaded or welded to valve member39. The spring is biased to urge upper portion44with insert member45into engagement with valve seat41provided on the valve seat collar50.

Locking elements74are shown inFIG. 5and include an arcuate, generally rectangular shaped body71with a curved inner face34. At its outer surface the edges of the top and bottom portions are beveled at72and73to allow the segments to more easily be located within the annular groove40in the bore33of the fluid end, thereby forming a locking ring (i.e, a ring of locking elements) when a sufficient number of locking elements74are placed substantially end to end within the groove40. A flow diverter80as shown inFIGS. 6 and 6ais positioned within the bore33at its opening.

A U-shaped seal120which includes an O-ring121positioned within the U-shaped channel is positioned between valve seat collar50and a recess in the inlet bore as shown inFIG. 3. These seals are available from Marco Rubber & Plastic Products, Inc., among others.

The manner of installing the valve assembly into the fluid end is as follows. Initially locking elements74are not located within the suction inlet bore. The valve assembly including the valve seat collar50and the valve39with spring37and spring retainer36may be threaded into the suction inlet bore33using a suitable tool having complimentary features that align and engage with tool receiving grooves61provided on the valve seat collar50, such that the valve head44faces the fluid head inlet chamber43. The valve assembly is inserted and threaded into the suction inlet bore33to a point where the shoulder48of valve seat collar50passes the inner top portion of groove40, thereby exposing the full dimensions of the annular groove40for accepting a plurality of locking elements74. A plurality of locking elements74, for example four locking elements74spaced equally around the annular groove40circumference, are now inserted and positioned in the annular groove40to form a locking ring. To retain the locking elements74within the annular groove40, the valve seat collar50is then backed out of the bore33to seat the shoulder48against the locking elements74thereby imparting a compressive force on the locking elements74and the wall of the annular groove40. In this position the high fluid pressure generated within the fluid end chamber during operation is withstood by both the threads52on the valve seat collar50and the locking elements74within annular groove40. A flow diverter80as shown, for example, inFIG. 6Ais then placed within the suction inlet bore33in the position as shown inFIG. 3and held in place by a suction manifold plate101attached to the fluid end31by any suitable means, for example, a threaded bolt or a threaded stud and nut. An annular ridge82of the flow diverter helps to maintain the plurality of locking elements74within the groove40, while the locking ring formed by the plurality of locking elements74supports the valve assembly within the suction inlet bore33by preventing the collar50from rotating out of the bore33due to the high fluid pressures.

To remove and repair or replace the suction valve assembly, the manifold cover plate101and flow diverter80are removed from the suction manifold. The valve removal tool is inserted into the valve seat collar to slightly screw member50into the valve inlet bore. At this point locking elements74may be removed from groove40and are withdrawn. Valve assembly51can now be entirely removed by screwing valve seat collar50out of bore33. A new or refurbished valve assembly can now be installed as described above.

A second embodiment of the invention is illustrated inFIG. 7wherein like components have the same reference member as the embodiment illustrated inFIGS. 3-6. Fluid end31includes suction inlet bore95having a recessed annular groove40. A valve seat collar151in this embodiment includes an annular ridge69, a main body90, and an upper threaded portion107. A valve member85has a lower portion87forming a valve face that cooperates with a frusto-conical valve seat surface103on an interior surface of valve seat collar151.

A spring guide and support member92is threaded at140into upper threaded portion107of the valve seat collar151. A spring93is supported between spring guide88and a shoulder84provided on the valve member85as shown inFIG. 7.

Valve seat collar51is externally threaded at111and cooperates with internal threads94provided in bore95. An O-ring122is captured within a groove123in inlet bore95and abuts against a beveled end portion141of valve seat collar51.

Before installing the valve assembly within the suction inlet bore95, the spring guide and support member92is threaded into valve seat collar151to compress the spring93such that valve member85is biased against the valve seat collar151. This valve assembly may then be placed within the bore. Once placed within the bore, the valve seat collar151is then threaded into the suction inlet bore95to a position where portion90clears groove40, thereby exposing the full dimensions of the annular groove40for accepting a plurality of locking elements74. This valve assembly may be provided as a single cartridge unit that is preassembled. Next, a plurality of locking elements74are positioned within the annular groove40as shown inFIG. 7to further retain the valve assembly within the suction inlet bore95. After the locking elements74are placed within the annular groove40, the valve seat collar151is then backed slightly out of the bore95in order to seat the shoulder152against the locking elements74, thereby imparting a compressive force on the locking elements74and the wall of the annular groove40, which also reduces the shear load felt by the threads111due to the pump operating pressures. Next, the flow diverter80is positioned within the suction inlet bore95such that annular ridge82of the flow diverter80is positioned between the locking elements74and the annular ridge69of the valve seat collar151, thereby effectively serving as a locking ring retainer. This arrangement prevents the locking segments from moving out of annular groove40, while the locking ring formed by the plurality of locking elements74supports the valve assembly within the suction inlet bore95by preventing the valve seat collar151from rotating out of bore95due to the high fluid pressures. Flow diverter80is held in position by a suction manifold plate101that is bolted or otherwise secured to fluid end31as previously mentioned. Removal can be accomplished simply by reversing the installation process beginning with removal of the suction manifold plate101, flow diverter80, and the locking elements74. The remaining valve assembly may they be removed from the suction inlet bore95as a unit.