Plunger with outlet valve assembly for plunger pumps

Abstract

A plunger pump includes a housing with a discharge valve in communication with an outlet. The housing includes a bore that slidably accommodates a plunger. The housing also includes an inlet. The plunger has a closed proximal end connected to an actuator and a distal end with an outlet valve. The plunger also includes a sidewall with an opening that is in communication with the inlet of the housing. Fluid flows through the inlet and through the opening and into the plunger. When the plunger is retracted away from the discharge valve, the outlet valve of the plunger opens thereby providing fluid for the housing bore. As the plunger is moved towards the discharge valve, pressure in the housing bore increases thereby opening the discharge valve and permitting the pressurized fluid to exit through the outlet.

1 . A plunger for a plunger pump, comprising:
 a sidewall extending between a proximal end and an open distal end, the sidewall having a plunger bore extending axially therethrough, the sidewall including at least one opening to receive fluid from an inlet of a plunger pump into the plunger bore;   a valve seat coupled to the distal end of the plunger;   an outlet valve head for sealable engagement with the valve seat;   a rod extending axially from the outlet valve head within the plunger bore, the rod having a proximal end coupled to a piston slidably received within the plunger bore, and a distal end coupled to the outlet valve head;   wherein the outlet valve head, the rod and the piston form a valve assembly movable between open and closed positions, wherein, in the closed position, the piston is at a first position and the outlet valve head is configured to sealably engage the valve seat, and, in the open position, the piston is moved distally away from the first position and the outlet valve head is moved away from the valve seat.   
     
     
         2 . The plunger of  claim 1  wherein the proximal end of the plunger is closed. 
     
     
         3 . The plunger of  claim 1  wherein the distal end of the plunger is threadably coupled to the valve seat. 
     
     
         4 . The plunger of  claim 1  further including a plurality of openings in the sidewall. 
     
     
         5 . The plunger of  claim 1  wherein the piston includes a metered passageway passing through the piston and providing limited communication between a portion of the piston bore disposed proximally of the piston and a portion of the piston bore disposed distally of the piston. 
     
     
         6 . The plunger of  claim 1  wherein the proximal end of the plunger includes at least one radially extending element for coupling the proximal end of the plunger to an actuator. 
     
     
         7 . The plunger of  claim 1  wherein the at least one radially extending element is a flange. 
     
     
         8 . A plunger pump, comprising:
 a housing assembly including an inlet, an outlet and an axial housing bore extending therebetween, the housing bore slidably accommodating a plunger;   the plunger including a sidewall extending between a proximal end and a distal end of the plunger and having a plunger bore extending axially therethrough, the plunger configured to receive fluid from an inlet of the plunger pump into the plunger bore;   a valve seat coupled to the plunger;   an outlet valve head for sealable engagement with the valve seat;   a rod extending axially from the outlet valve head within the plunger bore,   a piston coupled to a proximal end of the rod, and a distal end of the rod coupled to the outlet valve head, the piston being slidably received within the plunger bore;   wherein the outlet valve head, the rod and the piston form a valve assembly movable between open and closed positions, wherein, in the closed position, the piston is at a first position and the outlet valve head is configured to sealably engage the valve seat, and, in the open position, the piston is moved distally away from the first position and the outlet valve head is moved away from the valve seat.   
     
     
         9 . The pump of  claim 8  wherein the proximal end of the plunger is closed. 
     
     
         10 . The pump of  claim 8  wherein the distal end of the plunger is threadably coupled to the valve seat. 
     
     
         11 . The pump of  claim 8  wherein the housing bore accommodates a proximal seal and a middle seal, the inlet is disposed between the proximal and middle seals, the sidewall of the plunger further including a plurality of openings disposed between the proximal and middle seals in both the open and closed positions. 
     
     
         12 . The pump of  claim 8  wherein the piston includes a metered opening passing through the piston and providing limited communication between a portion of the piston bore disposed proximally of the piston and a portion of the piston bore disposed distally of the piston. 
     
     
         13 . The pump of  claim 8  wherein the proximal end of the plunger includes at least one radially extending element for coupling the proximal end of the plunger to an actuator. 
     
     
         14 . The pump of  claim 8  wherein the at least one radially extending element is a flange. 
     
     
         15 . The pump of  claim 8  wherein movement of the plunger towards the discharge valve assembly causes the discharge valve assembly to open. 
     
     
         16 . The pump of  claim 8  wherein movement of the plunger away from the discharge valve assembly causes the discharge valve assembly to close and the outlet valve assembly to open. 
     
     
         17 . A method for pumping hydraulic fracturing fluid, the method comprising:
 providing a pump with an inlet, an outlet, a proximal end, a distal end, and an axial housing bore which slidably receives a plunger;   retracting the plunger axially away from a discharge valve assembly connected to the outlet of the pump disposed at the distal end of the pump thereby reducing pressure in the axial housing bore of the pump to open an outlet valve assembly disposed at a distal end of the plunger;   providing communication between an inlet of the pump and the housing bore of the pump through open outlet valve assembly the plunger;   moving the plunger towards the discharge valve assembly thereby increasing pressure in the housing bore thereby closing the outlet valve assembly;   pressurizing at least a portion of the housing bore disposed between the outlet valve assembly of the plunger and the discharge valve assembly thereby opening the discharge valve assembly; and   dispensing fluid through the open discharge valve assembly to the outlet.   
     
     
         18 . The method of  claim 17  wherein the plunger includes an axial plunger bore that provides communication between the inlet of the pump and the housing bore when the outlet valve assembly is open. 
     
     
         19 . The method of  claim 17  wherein the outlet valve assembly further includes an outlet valve head connected to a rod that passes through the plunger bore before being connected to a piston, the method further including providing a metered opening that extends through the piston thereby providing communication between the inlet, a portion of the piston bore disposed distally of the piston and a portion of the piston bore disposed proximally of the piston; and
 dampening an engagement between the outlet valve head and the outlet valve seat as the outlet valve assembly closes flowing fluid from the proximal side of the piston, through the metered passageway and to the distal side of the piston as the piston moves towards the proximal end of the plunger. 
 
     
     
         20 . The method of  claim 19  wherein the outlet valve assembly includes an outlet valve head and an outlet valve seat disposed at a distal end of the plunger, the method further including replacing the outlet valve head by:
 withdrawing the plunger from the proximal end of the housing; 
 disengaging the outlet valve head from the distal end of the rod; 
 engaging a new outlet valve head onto the distal end of the rod; and 
 inserting the plunger into the proximal end of the housing. 
 
     
     
         21 . The method of  claim 19  further including replacing the outlet valve seat by:
 withdrawing the plunger from the proximal end of the housing; 
 pulling the outlet valve head, rod and piston out through the distal end of the plunger; 
 disengaging the outlet valve seat from the distal end of the plunger; 
 engaging a new outlet valve seat onto the distal end of the plunger; 
 reinserting the piston, rod and outlet valve head and back through the distal end of the plunger until the outlet valve head engages the new outlet valve seat; 
 reinserting the plunger through the proximal end of the housing.