Screw driven piston pump

Abstract

A fluid pump comprises an electric motor configured to provide a unidirectional rotational output. The fluid pump further comprises a screw drive coupled to the electric motor. The screw drive is configured to convert the unidirectional rotational output of the electric motor into reciprocating motion to linearly reciprocate a piston coupled to the screw drive.

What is claimed is: 
     
         1 . A fluid pump system comprising:
 an electric motor configured to provide a unidirectional rotational output; and   a screw drive coupled to the electric motor, the screw drive configured to convert the unidirectional rotational output of the electric motor into reciprocating motion to linearly reciprocate a piston coupled to the screw drive.   
     
     
         2 . The fluid system of  claim 1 , wherein the electric motor, the screw drive, and the piston are inline. 
     
     
         3 . The fluid pump of  claim 1 , wherein the electric motor is offset from the screw drive, the fluid pump further comprising a set of gears that couples the offset electric motor to the screw drive. 
     
     
         4 . The fluid pump of  claim 1 , wherein the electric motor is offset from the screw drive, the fluid pump further comprising a belt assembly that couples the offset electric motor to the screw drive. 
     
     
         5 . The fluid pump of  claim 1 , wherein the screw drive comprises:
 a rotatable element configured to be rotatably driven by the unidirectional rotational output of the electric motor; and   a reciprocating element configured to be driven reciprocally and linearly along the rotatable element by rotation of the rotatable element, the linear element coupled to the piston.   
     
     
         6 . The fluid pump of  claim 1 , wherein the screw drive comprises:
 a self-reversing screw having a double helix raceway comprising a first thread and a second thread, wherein the first thread is of a different handedness than the second thread; and   a nut.   
     
     
         7 . The fluid pump of  claim 6 , wherein the self-reversing screw is configured to be rotatably driven by the unidirectional rotational output of the electric motor and wherein the nut is configured to be moved reciprocally and linearly along the self-reversing screw by the rotation of the self-reversing screw, the nut coupled to the piston. 
     
     
         8 . The fluid pump of  claim 6 , wherein the nut is configured to be rotatably driven by the unidirectional rotational output of the electric motor and wherein self-reversing screw is configured to move reciprocally and linearly along the nut by the rotation of the nut, the screw coupled to the piston. 
     
     
         9 . The fluid pump of  claim 1  and further comprising:
 a controller configured to control rotation of the electric motor. 
 
     
     
         10 . The fluid pump of  claim 1  and further comprising:
 a fluid inlet configured through which a fluid is drawn into the pump by the motion of the pump rod; and 
 a fluid outlet through which the fluid in the pump is expelled by the motion of the pump rod. 
 
     
     
         11 . A plural component system comprising:
 a first fluid source configured to contain a first fluid;   a second fluid source configured to contain a second fluid;   a first fluid pump system configured to pump the first fluid from the first fluid source, the first fluid pump comprising:
 a first controller; 
 a first electric motor configured to generate a unidirectional rotational output; 
 a first screw drive, coupled to the electric motor, configured to convert the unidirectional rotational output of the first electric motor into reciprocating motion; and 
 a first pump rod coupled to the first screw drive and configured to be driven by the reciprocating motion of the first screw drive; and 
   a second fluid pump system configured to pump the second fluid from the second fluid source, the second fluid pump comprising:
 a second controller; 
 a second electric motor that generates a unidirectional rotational output; 
 a second screw drive, coupled to the second electric motor, that converts the unidirectional rotational output of the second electric motor into reciprocating motion; and 
 a second pump rod coupled to the second screw drive and driven by the reciprocating motion of the second screw drive. 
   
     
     
         12 . The plural component system of  claim 11 , wherein the first fluid source comprises a first 55-gallon drum and the second fluid source comprises a second 55-gallon drum. 
     
     
         13 . The plural component system of  claim 12 , wherein the first fluid pump system further comprises a first piston housing portion configured to house the first piston and wherein at least a portion of the first piston housing portion is configured to be disposed within the first fluid source during operation of the first fluid pump and wherein the second fluid pump further comprises a second piston housing portion configured to house the second piston and wherein at least a portion of the second piston housing portion is configured to be disposed within the second fluid source during operation of the second fluid pump. 
     
     
         14 . The plural component system of  claim 11 , wherein the first screw drive comprises a first nut and a first self-reversing screw, wherein one of the first nut and the first self-reversing screw is configured to be rotated by the unidirectional rotational output of the first electric motor to linearly and reciprocally drive the other; and
 wherein the second screw drive comprises a second nut and a second self-reversing screw, wherein one of the second nut and the second self-reversing screw is configured to be rotated by the unidirectional rotational output of the second electric motor to linearly and reciprocally drive the other.   
     
     
         15 . The plural component system of  claim 11 , wherein the first controller comprises a chief controller and the second controller comprises a worker controller, wherein the chief controller sends control communication to the worker controller, the worker controller configured to generate a control signal to control rotation of the second electric motor based on the control communication sent by the chief controller. 
     
     
         16 . The plural component system of  claim 11 , wherein the first fluid pump is mounted to the first fluid source, the first piston being disposed within an interior of the first fluid source and wherein the second fluid pump is mounted to the second fluid source, the second piston being disposed within an interior of the second fluid source. 
     
     
         17 . The plural component system of  claim 11 , wherein the first fluid pump can pressurize the first fluid up to at least 3000 pounds per square inch (PSI) and wherein the second fluid pump can pressurize the second fluid up to at least 3000 PSI. 
     
     
         18 . A fluid pump system comprising:
 a unidirectional electric motor configured to generate a unidirectional rotational output;   a drive comprising:
 a rotational element that is configured to be rotated by the unidirectional rotational output of the unidirectional electric motor; 
 a reciprocating element that is configured to be driven reciprocally along the rotational element by the rotation of the rotational element; 
   a fluid pump comprising:
 a piston rod coupled to the reciprocating element; and 
 a piston coupled to the piston rod, the piston rod configured to be reciprocally driven by reciprocation of the reciprocating element; 
   a fluid inlet through which fluid is drawn by reciprocation of the piston;   a fluid outlet through which fluid is expelled by reciprocation of the piston; and   a controller configured to control rotation of the electric motor.   
     
     
         19 . The fluid pump system of  claim 20 , wherein the rotational element comprises a nut and the reciprocating element comprises a self-reversing screw, the self-reversing screw including a coupling feature that provides a shoulder to retain a coupling mechanism that couples the piston rod to the self-reversing screw. 
     
     
         20 . The fluid pump system of  claim 20 , wherein the rotational element comprises a self-reversing screw and the reciprocating element comprises a nut, the nut coupled to a piston rod of the drive, the piston rod of the drive including a coupling feature that provides a shoulder to retain a coupling mechanism that couples the piston rod of the pump to the nut.