Plunger Pump, Plunger, and Method of Manufacturing Plunger Pump

Abstract

A plunger pump includes a pump fluid end having a fluid chamber and a suction bore, discharge bore, and plunger bore in communication with the fluid chamber. A plunger is arranged to reciprocate into and out of the fluid chamber through the plunger bore. The plunger has a plunger body with an inner cavity and an insert disposed in the inner cavity such that the combined stiffness of the insert and plunger body is greater than the stiffness of the plunger body. A crank mechanism is coupled to the plunger and operable to reciprocate the plunger.

1 . A plunger pump, comprising:
 a pump fluid end having a fluid chamber, a suction bore in communication with the fluid chamber, a discharge bore in communication with the fluid chamber, and a plunger bore in communication with the fluid chamber;   a plunger arranged to reciprocate into and out of the fluid chamber through the plunger bore, the plunger having a plunger body with an inner cavity and an insert disposed in the inner cavity, wherein a combined stiffness of the plunger body and insert is greater than a stiffness of the plunger body; and   a crank mechanism coupled to the plunger and operable to reciprocate the plunger.   
     
     
         2 . The plunger pump of  claim 1 , wherein the inner cavity occupies 30% to 60% of the volume of the plunger body. 
     
     
         3 . The plunger pump of  claim 1 , wherein the insert is configured such that there is an interference fit between an outer surface of the insert and an inner surface of the plunger body. 
     
     
         4 . The plunger pump of  claim 3 , wherein the insert is a hollow insert. 
     
     
         5 . The plunger pump of  claim 3 , wherein the insert is a solid insert. 
     
     
         6 . The plunger pump of  claim 3 , wherein a volume of the insert is 30% to 70% of a volume of the inner cavity. 
     
     
         7 . The plunger pump of  claim 1 , wherein the crank mechanism comprises a crosshead coupled to the plunger, a connecting rod coupled to the crosshead, and a crankshaft coupled to the connecting rod. 
     
     
         8 . The plunger pump of  claim 7 , wherein a coupling between the crosshead and connecting rod comprises a wrist pin coupled to the crosshead and retained to the connecting rod such that there is no relative rotation between the wrist pin and the connecting rod. 
     
     
         9 . The plunger pump of  claim 8 , wherein the wrist pin is retained to the connecting rod by inserting a retainer fastener through the connecting rod into a hole inside the wrist pin. 
     
     
         10 . The plunger pump of  claim 7 , wherein a coupling between the crosshead and connecting rod comprises a pair of surface holes in the connecting rod and a pair of wrist pins engaging the surface holes and retained to the crosshead. 
     
     
         11 . The plunger pump of  claim 7 , wherein the crank mechanism further comprises an extension rod coupling the plunger to the crosshead. 
     
     
         12 . The plunger pump of  claim 7 , wherein the crank mechanism further comprises an adapter plate coupling the plunger to the crosshead. 
     
     
         13 . The plunger pump of  claim 7 , wherein the wrist pin is received in a hole in the connecting rod, and wherein the hole and wrist pin are configured such that there is an interference fit between the wrist pin and the connecting rod. 
     
     
         14 . The plunger pump of  claim 1 , wherein the suction bore intersects the plunger bore, and wherein a transition between the suction bore and plunger bore comprises a fillet surface. 
     
     
         15 . The plunger pump of  claim 14 , wherein the discharge bore intersects the plunger bore, and wherein a transition between the discharge bore and plunger bore comprises a combination of a fillet surface, a reduced diameter bore, a tapered surface, and an enlarged diameter bore. 
     
     
         16 . The plunger pump of  claim 14 , wherein a tapered valve seat is formed in each of the suction bore and discharge bore. 
     
     
         17 . A plunger for a plunger pump, comprising:
 a plunger body having an inner cavity defined therein and an open end; and   an insert disposed in the inner cavity, the insert being configured such that a combined stiffness of the insert and plunger body is greater than a stiffness of the plunger body; and   an end cap mounted at the open end and adapted for coupling to an adapter plate or extension rod of a crank mechanism.   
     
     
         18 . The plunger of  claim 17 , wherein the inner cavity occupies 30% to 60% of the volume of the plunger body. 
     
     
         19 . The plunger of  claim 17 , wherein the insert is configured such that there is an interference fit between an outer surface of the insert and an inner surface of the plunger body. 
     
     
         20 . The plunger of  claim 17 , wherein the insert is a hollow insert. 
     
     
         21 . The plunger of  claim 17 , wherein the insert is a solid insert. 
     
     
         22 . The plunger of  claim 17 , wherein a volume of the insert is 30% to 70% of a volume of the inner cavity. 
     
     
         23 . A method of manufacturing a plunger pump, comprising:
 forming a pump fluid end having a fluid chamber, a suction bore and a discharge bore disposed along a first axis and intersecting with the fluid chamber, and a plunger bore disposed along a second axis that is perpendicular to the first axis and intersecting with the fluid chamber;   forming a plunger having a plunger body with an inner cavity;   disposing an insert in the inner cavity such that a combined stiffness of the plunger body and insert is greater than a stiffness of the plunger body;   arranging the plunger in the plunger bore; and   coupling a crank mechanism to the plunger to reciprocate the plunger into and out of the fluid chamber through the plunger bore.   
     
     
         24 . The method of  claim 23 , wherein coupling the crank mechanism comprises coupling a crosshead of the crank mechanism to the plunger and coupling a connecting rod of the crank mechanism to the crosshead, wherein coupling the connecting rod comprises retaining a wrist pin coupled to the crosshead to the connecting rod such that there is no relative motion between the wrist pin and the connecting rod. 
     
     
         25 . The method of  claim 23 , wherein forming the pump fluid end comprises forming a first transition between the suction bore and plunger bore comprising a first fillet surface and forming a second transition between the discharge bore and plunger bore comprising a second fillet surface.