BAGAGLI RICCARDO (IT)
TOGNARELLI LEONARDO (IT)
WO2013014550A1 | 2013-01-31 | |||
WO2008096213A1 | 2008-08-14 |
US5249600A | 1993-10-05 | |||
US7070166B1 | 2006-07-04 |
CLAIMS What is claimed is. 1. A valve for a reciprocating pump, the valve comprising: a valve seat having a seat rim; a valve body having a stop surface for mating with the seat rim of the valve seat, the valve body being moveable against and away from the valve seat between closed and opened positions; a seal member surrounding the stop surface of the valve body; at least one valve seat insert mounted on the seat rim of the valve seat; at least one valve body insert mounted on the stop surface of the valve body; and the valve body inserts and valve seat inserts being formed of a material harder and more wear resistant as compared to the valve seat and valve body; wherein the at least one valve body insert comprises a plurality of valve seat inserts spaced circumferentially around the seat rim of the valve seat and the at least one valve body insert comprises a plurality of valve body inserts spaced circumferentially around the stop surface of the valve body. 2. The valve according to claim 1, wherein the seal member is spaced radially outward and apart from the valve body inserts. 3. The valve according to claim 1, wherein: the stop surface comprises an annular area free from valve body inserts located radially outward from the valve body inserts; the seal member circumscribes the annular area; and the seat rim of the valve seat has an outwardly extended annular seat zone free from valve seat inserts so that the annular area and the seal member of the stop surface can selectively engage the annular seat zone of the seat rim. 4. The valve according to claim 1, wherein each valve body insert has a top surface for impacting a top surface of one of the valve seat inserts, the top surface of the valve body insert being positioned so that upon impacting the top surface of the valve seat insert, compression of the seal member is limited. 5. The valve according to claim 1, wherein the valve seat inserts and the valve body inserts comprise a carbide insert body having a synthetic diamonds layer. 6. The valve according to claim 1, wherein a top surface of each valve body insert does not protrude beyond the stop surface, and a top surface of each valve seat insert does not protrude beyond the seat rim. 7. A valve for a reciprocating pump, the valve comprising: a valve seat having a seat rim, the seat rim having a plurality of mounting holes spaced circumferentially around the seat rim; a valve body having a stop surface, the stop surface having a plurality of mounting holes spaced circumferentially around the stop surface; an insert located in each mounting hole of the valve seat and valve body, each insert comprising a cylindrical carbide insert body and an exposed top surface formed of a material harder and more wear resistant as compared to the valve seat and valve body; and a seal member surrounding the stop surface of the valve body for sealing engagement with the seat rim of the valve seat when the valve is in a closed position. 8. The valve according to claim 7, wherein the top surface of at least one valve body insert is positioned to selectively impact the top surface of at least one valve seat insert to limit the compression of the seal member. 9. The valve according to claim 7, wherein the top surface of each insert located in a mounting hole of the valve body does not protrude beyond the stop surface, and a top surface of each valve seat insert located in a mounting hole of the valve seat does not protrude beyond the seat rim. 10. The valve according to claim 7, wherein the seal member is spaced radially outward and apart from the inserts of the valve body and the stop surface comprises an annular area located between the inserts and the seal member, the annular area being free from inserts. 11. The valve according to claim 7, wherein the top surface of the each insert comprises synthetic diamonds. 12. A pump fluid end comprising: a fluid end block having a chamber, a suction valve conduit leading to the chamber, and a discharge valve conduit leading away from the chamber; a suction valve located within the suction valve conduit and a discharge valve located within the discharge valve conduit, each valve having a valve seat and a valve body; a seal member located on the valve body for sealing between the valve body and the valve seat, a suction valve spring that urges the valve body of the suction valve into a closed position in engagement with the valve seat of the suction valve, wherein pressure changes within the chamber cause the valve body of the suction valve to move to an open position away from the valve seat of the suction valve; a discharge valve spring that urges the valve body of the discharge valve into closed position in engagement with the valve seat of the discharge valve, wherein pressure changes within the chamber cause the valve body of the discharge valve to move to an open position away from the valve seat of the discharge valve; a plurality of inserts mounted on the valve seat and valve body of at least one valve; and the inserts being formed of a material harder and more wear resistant as compared to the valve seat and valve body wherein the valve seat has a seat rim, the plurality of valve seat inserts being spaced circumferentially around the seat rim. 13. The pump fluid end according to claim 12, wherein the valve body has a stop surface, the plurality of valve body inserts being spaced circumferentially around the stop surface. 14. The pump fluid end according to claim 12, wherein the inserts comprise a carbide insert body having a synthetic diamonds layer. 15. The pump according to claim 12, wherein the plurality of valve body inserts are mounted in a pattern such that at least one valve seat insert will mate with at least one valve body insert at every rotational relation between the valve seat and valve body. 16. The pump according to claim 12, wherein each valve body insert has a top surface for impacting a top surface of one of the valve seat inserts, the top surface of the valve body insert being positioned so that upon impacting the top surface of the valve seat insert, compression of the seal member is limited. 17. Fracturing pump comprising at least one valve according to any one of claims 1 to 6. |
INSERTS BACKGROUND 1. Field of the Disclosure [0001] The present disclosure relates in general to valves for use in reciprocating pumps, particularly hydraulic fracturing pumps for subterranean wells. 2. Background [0002] Hydrocarbon producing wellbores are sometimes stimulated to increase the production of hydrocarbons. Hydraulic fracturing, or fracing, is one example of stimulation, which involves pressurizing all or a portion of the wellbore to improve communication between the surrounding formation and the wellbore. A frac pump is used to pump a fracing fluid into a cased well. Subterranean fractures occur when the pressure exerted by the pumped fluid exceeds the fracture gradient of the formation strata. [0003] The frac pumps must be capable of pumping high volumes of fluid at high pressure. Reciprocating frac pumps have a fluid end and a power end. The fluid end has several plungers that reciprocate within a chamber. The chamber has an intake valve and a discharge valve, both of which open and close with each reciprocation cycle of the plunger. The valves have a valve body that mates with a valve seat. Typically, the fluid used for fracing is an acid slurry with a high concentration of sand. Bauxite, carbon dioxide, nitrogen, and additives can also be used. These fluids can be very abrasive and harsh on pump components, and in particular can cause wear on the mating valve body and valve seat surfaces of the intake valve and discharge valve. Wear on the valve body and valve seat can lead to the failure of the valve seal. [0004] Because of the high pressure environment, the harsh nature of the fracing fluid and the continuous opening and closing of the valves, they experience extensive wear. With the current valve designs, operators must change valves frequently, sometimes on a daily basis. Replacing the valves is expensive and time consuming. SUMMARY OF THE DISCLOSURE [0005] The current disclosure provides apparatus and method of increasing the service life of valves for hydraulic fracturing pumps. Synthetic diamond inserts which are chemically inert and extremely hard will resist impacts between the valve body and valve seat mating surfaces without wearing, preventing damage to the valve seals. This will increase the overall life of the valve. [0006] In one embodiment of the disclosure, a valve for a reciprocating pump includes a valve seat having a seat rim and a valve body having a stop surface for mating with the seat rim of the valve seat. The valve body is moveable against and away from the valve seat between closed and opened positions. A seal member surrounds the stop surface of the valve body. At least one valve seat insert is mounted on the seat rim of the valve seat and at least one valve body insert is mounted on the stop surface of the valve body. The valve body inserts and valve seat inserts are formed of a material harder and more wear resistant as compared to the valve seat and valve body. [0007] In certain embodiments, the valve seat inserts and the valve body inserts are mounted in a pattern such that at least one valve seat insert will mate with at least one valve body insert at every rotational relation between the valve seat and valve body. A plurality of valve seat inserts can be spaced circumferentially around the seat rim of the valve seat and a plurality of valve body inserts can be spaced circumferentially around the stop surface of the valve body. The seal member can be spaced radially outward and apart from the valve body inserts. [0008] In other embodiments, the stop surface has an annular area free from valve body inserts located radially outward from the valve body inserts. The seal member circumscribes the annular area. The seat rim of the valve can have an outwardly extended annular seat zone free from valve seat inserts so that the annular area and the seal member of the stop surface can selectively engage the annular seat zone of the seat rim. Each valve body insert can have a top surface for impacting a top surface of one of the valve seat inserts. The top surface of the valve body insert can be positioned so that upon impacting the top surface of the valve seat insert, compression of the seal member is limited. The valve seat inserts and the valve body inserts can be formed of a carbide insert body having a synthetic diamonds layer. In some embodiments, the top surface of each valve body insert does not protrude beyond the stop surface, and the top surface of each valve seat insert does not protrude beyond the seat rim. [0009] In other embodiments of the current application, a valve for a reciprocating pump includes a valve seat having a seat rim, the seat rim having a plurality of mounting holes spaced circumferentially around the seat rim. The valve also includes a valve body having a stop surface, the stop surface having a plurality of mounting holes spaced circumferentially around the stop surface. An insert is located in each mounting hole of the valve seat and valve body. Each insert can be a cylindrical carbide insert body with an exposed top surface formed of a material harder and more wear resistant as compared to the valve seat and valve body. A seal member surrounds the stop surface of the valve body for sealing engagement with the seat rim of the valve seat when the valve is in a closed position. [0010] In certain embodiments, the top surface of at least one valve body insert is positioned to selectively impact the top surface of at least one valve seat insert to limit the compression of the seal member. The valve according to claim 9, wherein the top surface of each insert located in a mounting hole of the valve body does not protrude beyond the stop surface, and a top surface of each valve seat insert located in a mounting hole of the valve seat does not protrude beyond the seat rim. The seal member can be spaced radially outward and apart from the inserts of the valve body. The stop surface can have an annular area located between the inserts and the seal member, the annular area being free from inserts. The top surface of the each insert can include synthetic diamonds. [0011] In yet other embodiments of the current application, a pump fluid end includes a fluid end block having a chamber, a suction valve conduit leading to the chamber, and a discharge valve conduit leading away from the chamber. A suction valve is located within the suction valve conduit and a discharge valve is located within the discharge valve conduit, each valve having a valve seat and a valve body. A seal member is located on the valve body for sealing between the valve body and the valve seat. A suction valve spring urges the valve body of the suction valve into a closed position in engagement with the valve seat of the suction valve. Pressure changes within the chamber can cause the valve body of the suction valve to move to an open position away from the valve seat of the suction valve. A discharge valve spring urges the valve body of the discharge valve into closed position in engagement with the valve seat of the discharge valve. Pressure changes within the chamber can cause the valve body of the discharge valve to move to an open position away from the valve seat of the discharge valve. A plurality of inserts are mounted on the valve seat and valve body of at least one valve. The inserts are formed of a material harder and more wear resistant as compared to the valve seat and valve body. [0012] In certain embodiments, the valve seat has a seat rim, the plurality of valve seat inserts being spaced circumferentially around the seat rim. The valve body can have a stop surface, the plurality of valve body inserts being spaced circumferentially around the stop surface. The inserts can be formed of a carbide insert body having a synthetic diamonds layer. [0013] In other embodiments, the valve body inserts are mounted in a pattern such that at least one valve seat insert will mate with at least one valve body insert at every rotational relation between the valve seat and valve body. Each valve body insert can have a top surface for impacting a top surface of one of the valve seat inserts. The top surface of the valve body insert can be positioned so that upon impacting the top surface of the valve seat insert, compression of the seal member is limited. BRIEF DESCRIPTION OF DRAWINGS [0014] Some of the features and benefits of the present disclosure having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: [0015] Figure 1 is a sectional view of a fluid end of a reciprocating pump. [0016] Figure 2 is an enlarged sectional view of a valve of the fluid end of Figure 1 in the open position, in accordance with an embodiment of this disclosure. [0017] Figure 3 is a top plan view of the valve seat of the valve of Figure 2. [0018] Figure 4 is a perspective view of an insert of the valve of Figure 2. [0019] While the disclosure will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the disclosure to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the disclosure as defined by the appended claims. DETAILED DESCRIPTION OF DISCLOSURE [0020] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. [0021] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. [0022] Referring to Figure 1, a fluid end 11 is a portion of a reciprocating pump of a type that is used for fracing operations. Fluid end 11 has a fluid end block 13 that contains chambers 15. Typically a reciprocating pump will include a fluid end block 13 with three to five separate chambers 15 (only one is shown). A plunger 17 is located in a plunger bore 19 that extends through fluid end block 13 and intersects chamber 15. Each of the individual chambers 15 will have a separate plunger 17. A plunger packing 21 creates a pressure and fluid seal between plunger bore 19 and plunger 17. A first end 23 of plunger 17 will extend into chamber 15 during the stroke cycle. In one type of fluid end, a pony rod 25 connects to a second end 27 of plunger 17. Pony rod 25 is stroked by a power source (not shown) to move plunger 17 between a discharge stroke and an intake stroke. [0023] Fluid end block 13 has a suction valve conduit 29 that leads into chamber 15 and a discharge valve conduit 31 that leads away from chamber 15 in a generally opposite direction to suction valve conduit 29. In the embodiment of Figure 1, the suction valve conduit 29 and discharge valve conduit 31 are coaxial and perpendicular to the plunger bore 19, however in other embodiments, suction valve conduit 29 and discharge valve conduit 31 can be angled relative to each other and at angles other than perpendicular to the plunger bore 19. [0024] A suction valve 33 is located within the suction valve conduit 29 and a discharge valve 35 is located within the discharge valve conduit 31. Suction valve 33 selectively allows fluid to enter into chamber 15 from an intake manifold 37. Discharge valve 35 selectively allows fluid to exit chamber 15. Each valve 33, 35 is biased by a spring 39 to a closed position. As pony rod 25 moves plunger 17 so that the first end 23 of plunger 17 is traveling away from chamber 15, the pressure differential between the pressure in the intake manifold 37 over the pressure in the chamber 15 is sufficient to overcome the bias of spring 39 of the suction valve 33. Suction valve 33 will then open and allow fluid to be admitted to chamber 15. As pony rod 25 moves plunger 17 so that the first end 23 of plunger 17 is traveling towards or farther into chamber 15, the pressure in chamber 15 is sufficient to overcome the bias of spring 39 of discharge valve 35. Discharge valve 35 will then open to allow fluid to exit chamber 15. [0025] Turning now to Figure 2, valve 41 can be either the suction valve 33 or the discharge valve 35. Valve 41 includes a valve body 43 that is typically of metal, such as steel. Valve 41 also includes a valve seat 45 that is also typically of metal, such as steel. Valve seat 45 is a generally tubular member with a seat rim 46 at one end and a circular shoulder 47 on an exterior surface of the valve seat 45. In the embodiment of Figures 1-2, seat rim 46 has a conical annular shape. In alternative embodiments, seat rim 46 can be generally perpendicular to a central axis of discharge valve 35, or can have other alternative shapes. Shoulder 47 engages a circular lip 49 (Figure 1) on an interior surface of the suction valve conduit 29 and discharge valve conduit 31, as appropriate, to support valve seat 45. A seal (Figure 1) can be located in a circular groove 51 in the exterior surface of valve seat 45 to create a seal between the valve seat 45 and the fluid end block 13 when the valve 41 is in a closed position. [0026] Valve body 43 has a stop surface 55 for mating with seat rim 46 of valve seat 45. In the embodiments of Figures 1-2, stop surface 55 is a sloped annular surface to match the conical annular shape of seat rim 46. In alternative embodiments, stop surface 55 will be shaped to match any alternative shape of seat rim 46. A seal member 57 surrounds stop surface 55. Seal member 57 can be molded in place within a recess in valve body 43 that surrounds and circumscribes stop surface 55. Seal member 57 is not positioned flush with stop surface 55, but instead has an end surface 58 that extends beyond stop surface 55. Seal member 57 can be of a polycarbonate, polyurethane or other seal material known in the art. Seal member selectively engages seat rim 46 to create a seal between the valve body 43 and valve seat 45. Valve body 43 moves against and away from valve seat 45 to move valve 41 between closed and open positions. Valve body 43 can include a guide member 59 that slides axially within an inner bore 61 of valve seat 45. Although a wing-guided poppet style valve has been illustrated in Figures 1-2, embodiments of the current disclosure incorporating the use of inserts 64 (Figure 4) can equally apply to stem-guided poppet valves, cone seat and ball poppet valves, or any other valve design suitable for hydraulic fracturing pump applications. [0027] Looking at Figures 2 - 3, a plurality of valve seat inserts 63 are mounted on the seat rim 46 of valve seat 45. Valve seat inserts 63 are spaced circumferentially around the seat rim 46 proximate to inner bore 61 of valve seat 45. A plurality of valve body inserts 65 are mounted on the stop surface 55 of the valve body 43. The valve body inserts 65 are spaced circumferentially around the stop surface 55 of the valve body 43. Inserts 63, 65 are mounted and positioned in a pattern that will cause at least one valve seat insert 63 to contact and mate with and at least one valve body insert 65. Because the valve body 43 is free to rotate relative to the valve seat 45, the pattern of inserts 63, 65 will allow for at least one valve seat insert 63 to contact and mate with and at least one valve body insert 65 at every possible rotational relation between the valve seat 45 and the valve body 43. The inserts 63, 65 can be sized and spaced to maximize contact between the valve seat inserts 63 and the valve body inserts 65 when the valve is in the closed position. [0028] In the embodiment of Figure 2, the valve seat inserts 63 are located proximate to the inner bore 61 of valve seat 45. The valve body inserts 65 are located on stop surface 55 at a similar radial location to valve seat inserts 63 so that the valve body inserts 65 line up axially with valve seat inserts 63. Seal member 57 is spaced radially outward and apart from the valve body inserts 65. This results in an annular area 69 of stop surface 55 that is free from valve body inserts 65. The seal member 57 circumscribes annular area 69. The seat rim 46 of the valve seat 45 has an extended annular seat zone 71 that extends outward beyond the valve seat inserts 63 so that annular seat zone 71 is free from valve seat inserts 63. When the valve 41 is in a closed position, the annular area 69 and seal member 57 can engage and mate with the annular seat zone 17 of the seat rim 46. [0029] Turning to Figure 4, insert 64 can be either valve seat insert 63 or valve body insert 65, Insert 64 is shown as cylindrical member with a circular cross section. In alternative embodiments, insert 64 could have other alternative shape or cross section. In another alternative embodiment, instead of a plurality of individual inserts, inserts 63 65 could comprise a single ring shaped member, one such ring shaped insert could be mounted on the seat rim 46 and another of such ring shaped insert can be mounted on valve seat 45. Insert 64 is formed of a material harder and more wear resistant as compared to the material of the valve seat 45 and valve body 43. Insert 64 could include, for example an exposed top surface 67 that is formed of synthetic diamonds, such as polycrystalline diamond, or other ultra-hard material that is tough enough to withstand the repeated impact between the valve seat 45 and valve body 43 and be chemically inert to withstand the harsh nature of the fracturing fluid. Top surface 67 is deposited on an insert body 68, which may be, for example of tungsten carbide or other carbide. Insert 64 can be mounted in valve seat 45 and valve body 43 by brazing insert body 68 into mounting holes 73 of the valve seat 45 and valve body 43. Alternatively, inserts 64 can be press or interference fit into mounting holes 73. Because the inserts 64 are formed of a hard, wear resistant material, after the useful life of the valve, inserts 64 may still be in good condition and could be removed and recycled for use on other valves 41. [0030] Returning to Figures 1-2, in an example of operation, as valve 41 moves to a closed position, the protruding end surface 58 of seal member 57 will contact seat rim 46 and will deform due to the force applied to valve body 43. When valve 41 is first used, the exposed top surface 67 of inserts 63, 65 can be flush, or slightly recessed within the seat rim 46 and stop surface 55, respectively. Therefore the annular area 69 can engage and mate with the annular seat zone 71 of the seat rim 46 to transfer the force to seat rim 46. Preferably, when surfaces 69,71 contact each other, a slight gap will exist between inserts 63, 65, at least initially. During a typical operation, wear will be encountered on, due to the erosive action of the fluids, the acidity and general harshness of the fluids, and the impact forces. In currently existing valves, over time, this will result in seal member 57 deforming more than originally. The additional deformation shortens the life of seal member 57. Once the seal member 57 fails and begins to leak, a high pressure stream of fluids passing by seal member 57 will quickly damage and destroy the components of valve 41. [0031] In embodiments of the present disclosure, as the seat rim 46 and stop surface 55 wear, the top surface 67 of the valve body inserts 65 will impact the top surface 67 of the valve seat inserts 63. This will reduce further wear on the seat rim 46 and stop surface 55. Seat rim 46 and stop surface 55 can continue to meet and mate to assist in forming a seal between the valve body 43 and valve seat 45, but in subsequent valve 41 closings, inserts 63, 65 will transfer the impact loads. Because inserts 63, 65 are of wear resistance material, the top surface 67 of the valve body inserts 65 will impact the top surface 67 of the valve seat inserts 63 without any additional deformation of seal member 57. The original positioning of top surfaces 67 of inserts 63, 65 will limit the compression of seal member 57, extending the life of seal member 57 and therefore the life of valve 41. [0032] The present disclosure described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the disclosure has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present disclosure disclosed herein and the scope of the appended claims.