Pump system

Abstract

A new and improved long stroke pump system used for wellbore hydraulic fracturing operations. The pump system comprises a power system, a drive system, and a frac fluid pumping assembly. The frac fluid pumping assembly comprises one or more pairs of hydraulic cylinders that are mechanically decoupled from each other but are hydraulically coupled to each other.

1 . A frac fluid pumping assembly, comprising:
 a first pair of hydraulic cylinders each having a cylinder rod extending at least partially from the first pair of hydraulic cylinders, wherein the first pair of hydraulic cylinders are mechanically decoupled from each other but are hydraulically coupled to each other;   a first pair of spacer spools;   a first spacer frame coupled at one end to the first pair of hydraulic cylinders and at an opposite end to the first pair of spacer spools; and   a fluid end assembly having a pair of fluid ends coupled to the first pair of spacer spools, wherein a plunger of each fluid end is coupled to one of the cylinder rods of the first pair of hydraulic cylinders.   
     
     
         2 . The frac fluid pumping assembly of  claim 1 , wherein each hydraulic cylinder comprises a cylinder housing, the cylinder rod at least partially disposed within the cylinder housing, and a piston coupled to the cylinder rod and forming fluid chambers within the cylinder housing. 
     
     
         3 . The frac fluid pumping assembly of  claim 2 , wherein the first pair of hydraulic cylinders are hydraulically coupled to each other such that an operating fluid is repeatedly pumped from the fluid chamber of one of the hydraulic cylinders into the fluid chamber of the other hydraulic cylinder and then back. 
     
     
         4 . The frac fluid pumping assembly of  claim 3 , wherein as the operating fluid is pumped out of one of the hydraulic cylinders, the cylinder rod of that hydraulic cylinder is at least partially further extended out of that cylinder housing in a discharge stroke. 
     
     
         5 . The frac fluid pumping assembly of  claim 4 , wherein as the operating fluid is pumped into one of the hydraulic cylinders, the cylinder rod of that hydraulic cylinder is at least partially retracted back into the cylinder housing in a suction stroke. 
     
     
         6 . The frac fluid pumping assembly of  claim 5 , wherein when the cylinder rod of one of the hydraulic cylinders is moved in a first direction in the discharge stroke, the cylinder rod of the other hydraulic cylinder is moved in an opposite, second direction in the suction stroke. 
     
     
         7 . The frac fluid pumping assembly of  claim 6 , wherein each plunger is at least partially disposed within one of the spacer spools that is coupled to one of the fluid ends. 
     
     
         8 . The frac fluid pumping assembly of  claim 7 , wherein a length of each cylinder housing is dimensioned to allow each plunger to be fully retracted from each spacer spool. 
     
     
         9 . The frac fluid pumping assembly of  claim 7 , wherein each fluid end comprises a suction valve assembly configured to direct fluid into the fluid end, and a discharge valve assembly configured to direct fluid out of the fluid end. 
     
     
         10 . The frac fluid pumping assembly of  claim 9 , wherein each fluid end is in fluid communication with a suction manifold and a discharge manifold. 
     
     
         11 . The frac fluid pumping assembly of  claim 1 , wherein the frac fluid pumping assembly further comprises a second pair of hydraulic cylinders that are mechanically decoupled from each other but are hydraulically coupled to each other. 
     
     
         12 . The frac fluid pumping assembly of  claim 11 , wherein the frac fluid pumping assembly further comprises a third pair of hydraulic cylinders that are mechanically decoupled from each other but are hydraulically coupled to each other. 
     
     
         13 . A pump system, comprising:
 a power system;   a drive system; and   the frac fluid pumping assembly of  claim 1 .   
     
     
         14 . The pump system of  claim 13 , wherein the drive system comprises one or more pumps and one or more pump manifolds configured to direct the operating fluid between the pairs of hydraulic cylinders that are hydraulically coupled to each other. 
     
     
         15 . The pump system of  claim 14 , wherein the power system is configured to power the one or more pumps. 
     
     
         16 . A frac fluid pumping assembly, comprising:
 a first hydraulic cylinder comprising a first cylinder housing, a first cylinder rod at least partially disposed within the first cylinder housing, and a first piston coupled to the first cylinder rod and forming a pump side fluid chamber and a plunger side fluid chamber within the first cylinder housing on opposite sides of the first piston;   a second hydraulic cylinder comprising a second cylinder housing, a second cylinder rod at least partially disposed within the second cylinder housing, and a second piston coupled to the second cylinder rod and forming a pump side fluid chamber and a plunger side fluid chamber within the second cylinder housing on opposite sides of the second piston; and   a pump configured to pump operating fluid into the pump side fluid chamber within the first cylinder housing, and configured to pump operating fluid into the pump side fluid chamber within the second cylinder housing, wherein the plunger side fluid chamber of the first cylinder housing is in fluid communication with the plunger side fluid chamber of the second cylinder housing.   
     
     
         17 . The frac fluid pumping assembly of  claim 16 , wherein the first cylinder rod is coupled to a first plunger that extends into a first fluid end, and wherein the second cylinder rod is coupled to a second plunger that extends into a second fluid end. 
     
     
         18 . The frac fluid pumping assembly of  claim 17 , wherein operating fluid is supplied from the plunger side fluid chamber of the first cylinder housing into the plunger side fluid chamber of the second cylinder housing to move the second piston, the second cylinder rod, and the second plunger in a suction stroke to draw fluid into the second fluid end. 
     
     
         19 . The frac fluid pumping assembly of  claim 18 , wherein operating fluid is supplied from the plunger side fluid chamber of the second cylinder housing back into the plunger side fluid chamber of the first cylinder housing to move the first piston, the first cylinder rod, and the first plunger in a suction stroke to draw fracing fluid into the first fluid end. 
     
     
         20 . The frac fluid pumping assembly of  claim 19 , wherein when the first piston, the first cylinder rod, and the first plunger move in the suction stroke, the second piston, the second cylinder rod, and the second plunger move in a discharge stroke to pump fracing fluid out of the second fluid end.