Fluid end with selectively coated surfaces

Abstract

A fluid end includes a block, a suction bore formed in the block and having a suction valve disposed within the suction bore, and a discharge bore formed in the block and having a discharge valve disposed within the discharge bore. The fluid end also includes a plunger bore formed in the block and having a plunger disposed therein, the plunger moveable in a first direction and a second direction opposite the first direction such that the plunger draws fluid through the suction valve when the plunger moves in the first direction and forces fluid through the discharge valve when the plunger moves in a second direction. The fluid end further includes a seal pack configured to maintain sealing contact with the plunger as the plunger moves in the first direction or the second direction and a coating applied to the block between the seal pack and the block.

What is claimed is: 
     
         1 . A fluid end comprising:
 a block;   a suction bore formed in the block and having a suction valve disposed within the suction bore;   a discharge bore formed in the block and having a discharge valve disposed within the discharge bore;   a plunger bore formed in the block and having a plunger disposed therein, the plunger moveable within the plunger bore in a first direction and a second direction opposite the first direction such that the plunger directs fluid through the suction valve when the plunger moves in the first direction and directs fluid through the discharge valve when the plunger moves in the second direction;   a seal pack disposed within the plunger bore and between the plunger and the block, thereby forming a fluid seal between the plunger and the block, the seal pack configured to maintain sealing contact with the plunger as the plunger moves in the first direction and the second direction; and   a coating disposed on a surface of the block within the plunger bore between the seal pack and the block.   
     
     
         2 . The fluid end of  claim 1 , wherein the surface is a first surface and the fluid end further comprises:
 a discharge valve seat disposed within the discharge bore, wherein the discharge valve is configured to rest against the discharge valve seat when the discharge valve is closed; and   an annular seal disposed between the discharge valve seat and the block, thereby providing a fluid seal between the discharge valve seat and the block, wherein the coating is disposed on a second surface of the block between the annular seal and the block.   
     
     
         3 . The fluid end of  claim 1 , wherein the surface is a first surface and the fluid end further comprises:
 a discharge cover disposed at least partially within the discharge bore; and   an annular seal disposed between the discharge cover and the block, thereby providing a fluid seal between the discharge cover and the block, wherein the coating is disposed on a second surface of the block between the annular seal and the block.   
     
     
         4 . The fluid end of  claim 1 , wherein the surface is a first surface and the fluid end further comprises:
 a suction valve seat disposed within the suction bore, wherein the suction valve is configured to rest against the suction valve seat when the suction valve is closed; and   an annular seal disposed between the suction valve seat and the block, wherein the coating is disposed on a second surface of the block between the annular seal and the block.   
     
     
         5 . The fluid end of  claim 1 , wherein the surface is a first surface and the fluid end further comprises:
 suction cover bore formed in the block;   a suction cover disposed within the suction cover bore, wherein the suction cover includes a seal disposed between the suction cover and the block, wherein the coating is disposed on a second surface of the block between the seal and the block; and   a suction cover retainer configured to secure the suction cover within the suction cover bore.   
     
     
         6 . The fluid end of  claim 1 , wherein the coating comprises a metal alloy and the coating is a thermal spray coating. 
     
     
         7 . The fluid end of  claim 6 , wherein the metal alloy comprises at least one of tungsten carbide, cobalt, or chromium. 
     
     
         8 . The fluid end of  claim 6 , wherein the thermal spray coating comprises a high velocity air fuel coating or a high velocity oxygen fuel coating. 
     
     
         9 . A fluid end comprising:
 a block;   a suction bore formed in the block on a first axis;   a discharge bore formed in the block on the first axis;   a plunger bore formed in the block on a second axis that is substantially perpendicular to the first axis;   a pump chamber formed at least partially between the suction bore, the discharge bore, and the plunger bore;   a coating disposed on one or more surfaces of the block within at least one of a portion of the suction bore, a portion of the discharge bore, or a portion of the plunger bore.   
     
     
         10 . The fluid end of  claim 9 , wherein the pump chamber is substantially free of the coating. 
     
     
         11 . The fluid end of  claim 9 , further comprising:
 a discharge valve disposed within the discharge bore;   a discharge valve seat disposed within the discharge bore, wherein the discharge valve is configured to rest against the discharge valve seat when the discharge valve is closed; and   an annular seal disposed between the discharge valve seat and the block, thereby forming a fluid seal between the discharge valve seat and the block, wherein the coating is applied to at least a portion of the discharge bore between the annular seal and the block.   
     
     
         12 . The fluid end of  claim 9 , further comprising:
 a suction valve disposed within the suction bore;   a suction valve seat disposed within the suction bore, wherein the suction valve is configured to rest against the suction valve seat when the suction valve is closed; and   an annular seal disposed between the suction valve seat and the block, thereby forming a fluid seal between the suction valve seat and the block, wherein the coating is applied to at least a portion of the suction bore between the annular seal and the block.   
     
     
         13 . The fluid end of  claim 9 , further comprising:
 a plunger disposed within the plunger bore, the plunger being moveable in a first direction and a second direction opposite the first direction; and   a seal pack configured to maintain sealing contact with the plunger as the plunger moves in the first direction and the second direction, wherein the coating is applied to at least a portion of the plunger bore between the seal pack and the block.   
     
     
         14 . The fluid end of  claim 9 , wherein the coating comprises a high velocity air fuel coating or a high velocity oxygen fuel coating. 
     
     
         15 . The fluid end of  claim 9 , wherein the coating comprises a metal alloy comprising at least one of tungsten carbide, cobalt, or chromium. 
     
     
         16 . A fluid system comprising:
 a fluid block;   a plunger bore formed in the fluid block and having a plunger disposed at least partially within the plunger bore, the plunger being moveable in a first direction and a second direction opposite the first direction;   one or more seals disposed within the plunger bore between the fluid block and the plunger, thereby forming a fluid seal between the plunger and the block, the one or more seals configured to maintain sealing contact with the plunger as the plunger moves in the first direction and the second direction; and   a coating disposed on a surface of the fluid block between the one or more seals and the fluid block.   
     
     
         17 . The fluid system of  claim 16 , wherein the surface is a first surface and the fluid system further comprises:
 a suction bore formed in the fluid block;   a suction valve seated within the suction bore;   a suction valve seat disposed within the suction bore, wherein the suction valve is configured to rest against the suction valve seat when the suction valve is closed, and the suction valve is configured to open when the plunger moves in the first direction; and   an O-ring disposed between the suction valve seat and the fluid block forming a fluid seal between the suction valve seat and the block, wherein the coating is disposed on a surface of the fluid block between the O-ring and the fluid block.   
     
     
         18 . The fluid system of  claim 16 , wherein the surface is a first surface and the fluid system further comprises:
 a discharge bore formed in the fluid block;   a discharge valve seated within the discharge bore;   a discharge valve seat disposed within the discharge bore, wherein the discharge valve is configured to rest against the discharge valve seat when the discharge valve is closed; and   an O-ring disposed between the discharge valve seat and the fluid block forming a fluid seal between the discharge valve seat and the block, wherein the coating is disposed on a second surface of the fluid block between the O-ring and the fluid block.   
     
     
         19 . The fluid system of  claim 16 , wherein the plunger is coupled to a pump motor that drives the plunger in the first direction and the second direction. 
     
     
         20 . The fluid system of  claim 16 , wherein the coating comprises a high velocity air fuel coating or a high velocity oxygen fuel coating.