1. Field of the Invention
The present invention relates generally to reciprocating pumps, more specifically to a coolant system for the piston and liner of the reciprocating pumps.
2. Background of the Invention
In oil field operations, reciprocating pumps are often used for various purposes. Some reciprocating pumps, generally known as “mud pumps,” are typically used for well drilling operations. During operation, the pistons and liners of the pumps generate large amounts of heat due to friction. It is desirous to cool the liners and pistons in order to extend their operation lives, which in turn increases overall efficiency and reduces down-time for maintenance.
Prior systems for cooling pistons and liners includes various coolant injector systems. For example, in one system, a coolant line or hose is physically coupled to the piston rod with a the hose feeding into the piston. The coolant hose moves with the piston rod during operations. The hose in this system typically has a short life due to wear associated with moving with the piston rod. Another system includes a hose that connects to an outer surface of the piston rod that transmits the coolant through the piston rod to a sprayer located in the piston rod adjacent the piston. The hose in this assembly also has problems with wear because the hose connects to and reciprocates with the piston rod.
In this invention, a reciprocating pump assembly includes piston rod that is movable and reciprocates in order to pump a fluid. The piston rod has a piston portion at an end that stokes within a piston chamber. The pump assembly also includes a piston rod sleeve that houses the piston rod. The piston rod sleeve does not reciprocate with the piston rod, so the piston rod sleeve remains stationary. The piston rod sleeve also defines and annulus between the piston rod and the piston rod sleeve. The pump assembly has a fluid line that leads into the annulus. The fluid line delivers coolant to the annulus. The pump assembly also includes a flow passage. The flow passage has an inlet in fluid communication with the annulus for receiving the coolant. The passage also has an outlet in fluid communication with the piston chamber for delivering the coolant.
The flow passage of the pump assembly may be located within the piston rod. As such, the coolant flows through an interior of the piston rod between the inlet and outlet of the flow passage. The pump assembly can also include a fluid sprayer. The sprayer is typically located at the outlet of the flow passage in order to deliver a spray of fluid into the piston chamber.
The piston rod can include an outer shell that has an inner circumference. The piston rod can also include a pony rod that is located within the outer shell and has an outer circumference that is less than inner circumference of the outer shell. The pony rod and the outer shell define a clearance between the inner surface of the outer shell and the outer surface of the pony rod. The clearance can be a portion of the flow passage for carrying the coolant from the annulus and the piston chamber.
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Piston rod 33 also preferably includes a tubular extension or extension rod 41 connected to the ends of pony rod 39 and outer casing 37. Extension rod 41 extends longitudinally away from crankshaft 25 (
The flared portions of intermediate casing 45 and extension rod 41 abut and are held relative to each other by an outer clamp 47. Outer clamp 47 encloses the interface of intermediate casing 45 and extension rod 41. Outer clamp 47 has a recess portion which surrounds the flared portions of extension rod 41 and intermediate casing 45. Therefore, as outer casing 37 reciprocates longitudinally toward and away from crankshaft 25, extension rod 41 must also reciprocate toward and away crankshaft 25.
In the preferred embodiment, extension rod 41 is a tubular member which also receives and encloses a portion of pony rod 39. Preferably an inner sleeve 49, having a threaded profile that matingly engages with the threaded profile located toward the end of pony rod 39 extending away from crankshaft 25, is positioned at the interface of intermediate casing 45 and extension rod 41. Intermediate casing 45 preferably includes an inner bore which receives a portion of inner sleeve 49 and prevents inner sleeve 49 from moving relative to intermediate casing 45 closer to crankshaft 25. Extension rod 41 also preferably has an inner bore which receives a portion of inner sleeve 49, which prevents inner sleeve 49 from moving relative to extension rod 41. In the preferred embodiment, an extension rod annulus 50 is defined between piston 35, inner sleeve 49, the end of pony rod 39 extending away from crankshaft 25, and the interior of extension rod 41. Piston 35 connects to the end of extension rod 41 extending away from rod clamp assembly 45. In the preferred embodiment, a plurality of passages 51 extend longitudinally through inner sleeve 49, between rod annulus 40 and extension rod annulus 50, around the threaded portion of pony rod 39 so that rod annulus 40 and extension annulus 50 are in fluid communication through rod clamp assembly 43.
A piston liner 55 adjoins to an interior surface of cylinder 17. In the preferred embodiment, piston liner 55 is in fluid communication with an interior portion of cylinder 17 and thereby defining a pumping chamber of reciprocating pump assembly 11. Piston 35 slidingly engages piston liner 55 as piston 35 reciprocates longitudinally toward and away from crankshaft 25. Reciprocating piston 35 within piston liner 55 causes the volume of the pumping chamber to increase and decrease as piston 35 reciprocates longitudinally toward and away from crankshaft 25, thereby positively displacing the fluid being pumped through reciprocating pump 11.
Piston 35 typically experiences wear from the heat created by sliding engagement of piston liner 55 during normal pumping operations. Typically the fluid being pumped through the pumping chamber of reciprocating pump 11 helps to lubricate and cool the portion of piston liner 55 on the cylinder side of piston 35. A coolant assembly 57 provides coolant to the crankshaft 25 side of piston 35 to prevent excessive heat and wear between piston 35 and piston liner 55. In the preferred embodiment, coolant assembly 57 preferably includes a piston rod sleeve or coolant sleeve 59 extending between crosshead housing 32 and the portion of crankshaft housing 13 that engages piston rod housing 15. Coolant sleeve 59 preferably encloses outing casing 37 of piston rod 33 and is stationary. Seals 61 preferably seal the end of coolant sleeve 59 adjacent crosshead housing 32 and the end of connector sleeve 59 adjacent rod clamp assembly 43. The interior surface of coolant sleeve 59 and seals 61 thereby define a sleeve annulus 63 surrounding outer casing 37 of piston rod 33. In the preferred embodiment, a fluid line or injector hose 65 injects a coolant into sleeve annulus 63 through a sleeve port 67 extending through a side of sleeve 59. Injector hose 65 typically extends away from lubricator sleeve 59 to an outer surface of crankshaft housing 13 to receive the coolant from a coolant source (not shown).
In the preferred embodiment, seal 61 located adjacent crosshead housing 32 is placed a predetermined distance from seal 61 located adjacent the end of crankshaft housing 13 extending away from crankshaft 25, such that the distance between seals 61 is greater than or substantially equal to the length of the stroke of piston 35. In the preferred embodiment, an outer shell or casing port 69 extends through a side of outer casing 37 of piston rod 33. Rod annulus 40 and sleeve annulus 63 are in full communication through outer casing port 69. Rod annulus 40 and sleeve annulus 63 are in fluid communication throughout the entire stroke length of the piston rod. In the preferred embodiment, outer casing port 69 is formed on a portion of outer casing 37 such that outer casing port 69 is always substantially between seals 61 during operations of reciprocating pump 11. Therefore, coolant from injector hose 65 that accumulates in sleeve annulus 63 can readily communicate through outer casing port 69 into rod annulus 40 while piston rod 33 reciprocates toward and away from crankshaft 25. In the preferred embodiment, the coolant that communicates from sleeve annulus 63 through outer casing port 69 travels along pony rod 33 toward passages 51 and inner sleeve 49. The coolant communicates through passages 51 from rod annulus 40 and into extension annulus 50 toward piston 35.
Referring to
Coolant assembly 57 advantageously provides coolant to the crankshaft 25 side of piston 35 and piston liner 55. This reduces excessive heat and wear between piston 35 and piston liner 55. Coolant assembly 57 also advantageously provides and assembly in which fluid line or fluid hose 65 remains stationary during pump operations. Therefore, hose 65 is not subject to the reciprocating movements that cause wear and failure in previous cooling assemblies. Accordingly, pumping operations can continue for longer periods of time between replacement of the fluid hose 65.
While the invention has been shown in only one 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. For example, injector hose 65 can extend from lubricator sleeve 59 toward a side portion of crankshaft housing 13 as shown in
This nonprovisional patent application claims the benefit of co-pending, provisional patent application U.S. Ser. No. 60/476,746, filed on Jun. 6, 2003, which is hereby incorporated by reference in its entirety.
Number | Name | Date | Kind |
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1537851 | Maingault | May 1925 | A |
2250419 | Johnston et al. | Jul 1941 | A |
2439958 | Anderson | Apr 1948 | A |
3394633 | Payne et al. | Jul 1968 | A |
3782123 | Muschalek, Jr. | Jan 1974 | A |
6315537 | Helbing et al. | Nov 2001 | B1 |
20040244576 | Kugelev et al. | Dec 2004 | A1 |
Number | Date | Country |
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235939 | Jun 1925 | GB |
Number | Date | Country | |
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20040244576 A1 | Dec 2004 | US |