Reciprocating Pump Having a Combination Check Valve and Relief Valve

Abstract

A reciprocating pump having a combination check valve and relief valve is disclosed. The pump includes a pump body having an inlet, an outlet and a pumping chamber. A biasing element provides a force that biases a movable seat toward sealing engagement between a first region of the movable seat and a fixed seat at the inlet. A movable checking element is movable away from a second region of the movable seat when fluid flows in one direction through a passageway in the movable seat. The movable seat also acts as a relief valve wherein the first region of the movable seat disengages the fixed seat if the movable checking element is being forced into engagement with the second region of the movable seat by a force that exceeds the force of the biasing element against a third region of the movable seat.

1 . A reciprocating pump having a combination check valve and relief valve, comprising:
 a pump body further comprising an inlet, an outlet and a pumping chamber in fluid communication between the inlet and the outlet;   a fixed seat at the inlet;   a biasing element seat at the inlet;   a biasing element that engages the biasing element seat;   a movable checking element;   a movable seat having a passageway therethrough and a first region that engages the fixed seat, a second region that engages the movable checking element, and a third region that engages the biasing element;   wherein the biasing element provides a force that biases the movable seat toward sealing engagement between the first region of the movable seat and the fixed seat, the movable checking element is movable away from the second region of the movable seat when fluid flows in one direction through the passageway in the movable seat, and the movable seat acts as a relief valve wherein the first region of the movable seat disengages the fixed seat if the movable checking element is being forced into engagement with the second region of the movable seat by a force that exceeds the force of the biasing element against the third region of the movable seat.   
     
     
         2 . The reciprocating pump of  claim 1 , wherein the movable seat has first and second faces. 
     
     
         3 . The reciprocating pump of  claim 2 , wherein the first and second faces are on opposed sides of the movable seat. 
     
     
         4 . The reciprocating pump of  claim 2 , wherein the first and second regions of the movable seat are located on the first face of the movable seat, and the third region of the movable seat is located on the second face of the movable seat. 
     
     
         5 . The reciprocating pump of  claim 2 , wherein the first, second and third regions of the movable seat are located on the first face of the movable seat. 
     
     
         6 . The reciprocating pump of  claim 1 , wherein the biasing element is a compression spring, a tension spring or a torsion spring. 
     
     
         7 . The reciprocating pump of  claim 1 , wherein the biasing element force is adjustable. 
     
     
         8 . The reciprocating pump of  claim 7 , wherein the biasing element force is adjusted by displacement of the biasing element seat. 
     
     
         9 . The reciprocating pump of  claim 8 , wherein the biasing element seat is displaceable by a screw or spacer. 
     
     
         10 . The reciprocating pump of  claim 1 , wherein the movable checking element is a ball, a flapper or a poppet. 
     
     
         11 . The reciprocating pump of  claim 1 , wherein the movable checking element is movable axially or rotationally. 
     
     
         12 . The reciprocating pump of  claim 1 , wherein the movable seat is movable axially or rotationally. 
     
     
         13 . The reciprocating pump of  claim 1 , wherein the movable checking element is forced into engagement with the second region of the movable seat by a second biasing element. 
     
     
         14 . The reciprocating pump of  claim 13 , wherein the second biasing element has a lower spring force that the first biasing element. 
     
     
         15 . The reciprocating pump of  claim 13 , wherein the second biasing element engages a second biasing element seat in the inlet. 
     
     
         16 . The reciprocating pump of  claim 1 , wherein the reciprocating pump further comprises a piston in communication with the pumping chamber. 
     
     
         17 . The reciprocating pump of  claim 1 , wherein the reciprocating pump further comprises a diaphragm in communication with the pumping chamber.