1. Technical Field
The present invention relates in general to reciprocating pumps and, in particular, to an improved system, method, and apparatus for a suction valve stop assembly in a reciprocating pump.
2. Description of the Related Art
In oil field operations, reciprocating pumps are often used for various purposes. Some reciprocating pumps, generally known as “service pumps,” are typically used for operations such as cementing, acidizing, or fracing a well. Typically, these service pumps run for relatively short periods of time, but they operate on a frequent basis. Often they are mounted to a truck or a skid for transport to various well sites. A pump might operate several times a week. In many applications, several pumps are connected in parallel to a single flow line.
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Importantly, suction cover 115 utilizes a set screw 122 that engages a threaded hole in cylinder 105, which thereby prevents rotation of suction cover 115 during operation. It is the eccentric positioning of the hub 123 that necessitates set screw 122 due to the torque applied by the valve spring retainer 117.
Suction cover assembly 113 can be disassembled and reassembled to provide access to and reseal the cylinder 105, respectively. However, the diametral clearance between suction cover 115 and valve spring retainer 117 (approximately 0.030″) is so tight that it is very difficult to realign and reseat these components with respect to the eccentric hub 123, which must be carefully repositioned to properly make-up with and support the valve spring retainer 117.
Since the clearance is tight, suction cover 115 not only guides valve spring retainer 117, but also supports the valve stop. Forces from fluid flow and spring 119 translate to the suction cover 115, and promote untimely failure of the suction cover 115 and cylinder 105. That tendency increases with time as cylinder 105 and valve spring retainer 117 engage and wear on each other due to the tight clearance. In addition, it is very difficult to align the eccentric hub 123 to valve spring retainer 117, and the set screw 122 to the hole in the cylinder 105 at the same time. Thus, an improved design for facilitating engagement between the various components of suction cover assemblies is needed.
One embodiment of a system, method, and apparatus for a reciprocating pump assembly includes a pump housing that houses a crankshaft. A plurality of plungers are mechanically connected to the crankshaft for pumping a fluid through a plurality of cylinders or plunger chambers. Each of the cylinders has a fluid inlet port and a fluid outlet port.
The pump also has an opening for providing access to the cylinder. A suction cover is mounted in the opening and has a concentric hub protruding from the suction cover into the cylinder. The hub is coaxial with an axis of the opening and the suction cover. A suction valve stop is mounted adjacent one of the fluid ports and has a spring retainer for retaining a spring relative to the fluid port. A column extends from the spring retainer, and a bushing is mounted to the spring retainer for engaging and being retained by the coaxial hub of the suction cover. The suction cover guides the suction valve stop in an operational position and, when the suction cover is removed from the opening, the suction valve stop is movable to a non-operational position.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
So that the manner in which the features and advantages of the invention, as well as others which will become apparent are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the drawings illustrate only an embodiment of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
Referring to
Referring to
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In one embodiment, a gear 24 is mechanically connected to crankshaft 25 and is rotated by the motor through gears 26 and 24. A connector rod 27 connects to a crosshead 29 through a crosshead pin 31, which holds connector rod 27 longitudinally relative to crosshead 29. Connector rod 27 pivots about crosshead pin 31 as crankshaft 25 rotates with the other end of connector rod 27. A plunger rod 33 extends from crosshead 29 in a longitudinally opposite direction from crankshaft 25. Connector rod 27 and crosshead 29 convert rotational movement of crankshaft 25 into longitudinal movement of plunger rod 33.
A plunger 35 is connected to plunger rod 33 for pumping the fluid passing through cylinder 17. Cylinder 17 connects to the end of plunger rod housing 15 extending away from crankshaft housing 13 (
Plunger 35 reciprocates, or moves longitudinally toward and away from cylinder 17, as crankshaft 25 rotates. As plunger 35 moves longitudinally away from cylinder chamber 39, the pressure of the fluid inside chamber 39 decreases creating a differential pressure across inlet valve 41, which actuates valve 41 and allows the fluid to enter cylinder chamber 39 from fluid inlet 19. The fluid being pumped enters cylinder chamber 39 as plunger 35 continues to move longitudinally away from cylinder 17 until the pressure difference between the fluid inside chamber 39 and the fluid in fluid inlet 19 is small enough for inlet valve 41 to actuate to its closed position. As plunger 35 begins to move longitudinally towards cylinder 17, the pressure on the fluid inside of cylinder chamber 39 begins to increase. Fluid pressure inside cylinder chamber 39 continues to increase as plunger 35 approaches cylinder 17 until the differential pressure across outlet valve 43 is large enough to actuate valve 43 and allow the fluid to exit cylinder 17 through fluid outlet 21. In one embodiment, fluid is only pumped across one side of plunger 35, therefore reciprocating pump 12 is a single-acting reciprocating pump.
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In one embodiment, the spring retainer 71 has an axis 79 (
The present invention provides the suction valve stop assembly 51 with a large amount of diametral clearance compared to the prior art. For example, in some embodiments the present invention has approximately 0.025″ more clearance than the prior art (i.e., a total of about 0.060″). This example is merely illustrative and is no way is meant to limit the scope of the present invention. This relatively large amount of diametral clearance is accommodated between the hub 65 of the suction cover 55 and the bushing 77 of the suction valve stop 53. However, the clearance is sufficient to maintain engagement between suction cover 55 and suction valve stop 53 during operation. The range of diametral clearance between the suction cover 55 and the suction valve stop 53 compensates for wear between the cylinder 17 and the suction valve stop 53, and maintains engagement between the suction cover 55 and the suction valve stop 53 during operation, such that the suction cover 55 continues to merely guide but does not structurally support or cause wear on the suction valve stop 53 or cylinder 17.
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.
Number | Name | Date | Kind |
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2776701 | Denis | Jan 1957 | A |
4861241 | Gamboa et al. | Aug 1989 | A |
6910871 | Blume | Jun 2005 | B1 |
7186097 | Blume | Mar 2007 | B1 |
Number | Date | Country |
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1449280 | Sep 1976 | GB |
Number | Date | Country | |
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20060029502 A1 | Feb 2006 | US |