A pump with racks and pinion

Abstract

A pump, in particular a heavy-duty pump for pumping liquid or mixtures of liquids and particulate material, such as mud, proppant and concrete, said pump having at least one electric motor (15) coupled to a gear assembly (17), said gear assembly (17) in turn being coupled to at least one pinion (13, 14). The at least one pinion (13, 14) is meshing with two racks (9, 10) that are arranged in parallel on the same side of said pinion (13, 14) and said piston rod is arranged between the two racks (5, 6). The piston rod is operatively coupled to the set of racks (5, 6). The piston rod has at least one piston, or alternatively being coupled to a combined piston rod and piston (5, 6). The piston is received within a pump cylinder (1, 2) chamber.

1 . A pump, in particular a heavy-duty pump for pumping liquid or mixtures of liquids and particulate material, such as mud, proppant and concrete, the pump having at least one electric motor coupled to a gear assembly, the gear assembly in turn being coupled via at least one pinion to at least one toothed rack that in turn is coupled to at least one piston rod, the piston rod having at least one piston, or alternatively being coupled to a combined piston rod and piston, the piston being received within a pump cylinder chamber, wherein each of the two pinions are driving one of the racks the pinions meshing with two racks that are arranged in parallel on the same side of the pinion and the piston rod being arranged between the two racks, the piston rod being operatively coupled to the set of racks. 
     
     
         2 . The pump of  claim 1 , wherein the two racks are interconnected by a coupling assembly, the coupling assembly being coupled to the at least one piston. 
     
     
         3 . The pump of  claim 2 , wherein the coupling assembly comprises a link that is rotatably attached to the interconnected piston rods and rotatably attached to the racks. 
     
     
         4 . The pump of  claim 3 , wherein the link is arranged coinciding with the longitudinal axis of the piston rods. 
     
     
         5 . The pump of  claim 1 , wherein the racks have a guide rail on the opposite side of the rack from the toothing. 
     
     
         6 . The pump of  claim 1 , wherein the set of racks is coupled to two oppositely acting and interconnected piston rods. 
     
     
         7 . The pump of  claim 6 , wherein that the cylinders of the piston rods are connected to a drive housing, the drive housing surrounding the at least one pinion, the racks and exposed parts of the piston rods. 
     
     
         8 . The pump of  claim 7 , wherein the drive housing comprising a central part extending between the cylinders and extension housings attached to the central part, the extension housings surrounding the racks along their travelling path outside the central part. 
     
     
         9 . The pump of  claim 1 , wherein at least two pump cylinder chambers are arranged side by side and are coupled to a respective valve block, the valve blocks being coupled to a common header. 
     
     
         10 . The pump of  claim 9 , wherein the pistons arranged in the at least two pump cylinder chambers are driven by separate electric motors, at least one pressure sensor being arranged in the header, the sensor being coupled to a processor that controls the rotation of the electric motors, each motor having an encoder detecting the angular position of the motor, the encoder being coupled to the processor, the processor being set up to adjust the speed and hence the angular position of the motors when the difference in pressure in the header is greater than a predetermined tolerance. 
     
     
         11 . The pump of  claim 10 , wherein each of the motors are operating at least two oppositely arranged and interconnected piston rods, the piston rods each having a piston that is received within a respective one of two oppositely arranged pump cylinder chambers, the cylinder chambers together with adjacent cylinder chambers forming a set of first cylinder chambers on a first side of the pump and a set of second cylinder chambers on a second side of the pump, the set of first cylinder chambers being coupled to a first common header and the set of second cylinder chambers being coupled to a second common header. 
     
     
         12 . The pump of  claim 10 , wherein the processor is set up to drive the motors at an initial angular separation equal to 360° divided by the number of motors. 
     
     
         13 . The pump of  claim 10 , wherein the processor is configured to adjust the angular separation of the motors to obtain an even flow out of the header.