Systems and methods for analyzing an infusion pump are provided. One infusion pump analyzer includes a fluid flow path configured to be coupled to an infusion pump to be tested and a pair of fluid chambers. The infusion pump analyzer further includes dual linear piston pumps coupled with the pair of fluid chambers and the fluid flow path to control the flow of fluid therethrough, and a valve coupled with the pair of fluid chambers and configured to rotate to selectively fill and drain the pair of fluid chambers.

Systems and methods for analyzing an infusion pump are provided. One infusion pump analyzer includes a fluid flow path configured to be coupled to an infusion pump to be tested and a pair of fluid chambers. The infusion pump analyzer further includes dual linear piston pumps coupled with the pair of fluid chambers and the fluid flow path to control the flow of fluid therethrough, and a valve coupled with the pair of fluid chambers and configured to rotate to selectively fill and drain the pair of fluid chambers.

A pumping unit (20) includes a hopper assembly (24) for holding material to be pumped, a pair of identical pumping assemblies (26, 28), and a pumped material outlet (30). The assemblies (26, 28) include directional or spool valves (54) having rotatable spools (76), tubular pumping chambers (56), and pistons (122) within the chambers (56). The pistons (122) include concave operating faces (134), which are complemental and mate with the outer surfaces of the spools (76). Operation of the unit (20) creates successive charges of pumped materials having a minimum of disruptions, such as tearing or smearing.

A system for delivering pressurized fracking fluid to a well includes a high-pressure pump pumping proppant-free fluid, and a double-piston pressure transfer arrangement for transferring pressure from the proppant-free fluid to a fracking fluid. The pressure transfer arrangement includes first and second cylinder assemblies, each having a piston in sliding engagement within a first hollow cylinder so as to define first and second chambers of the first cylinder and third and fourth chambers of the second cylinder. A piston rod interconnects the pistons. A flow selector alternately directs high-pressure proppant-free fluid to the first chamber and the third chamber so as to act on the pistons, thereby applying pressure to fracking fluid within the second and fourth chambers, respectively, for delivery to the well in alternate power strokes. The faces of the pistons facing the first and third chambers have a smaller effective surface area than the faces towards the second and fourth chambers such that pressure in the fracking fluid remains lower than pressure in the proppant-free fluid.

A system for delivering pressurized fracking fluid to a well includes a high-pressure pump pumping proppant-free fluid, and a double-piston pressure transfer arrangement for transferring pressure from the proppant-free fluid to a fracking fluid. The pressure transfer arrangement includes first and second cylinder assemblies, each having a piston in sliding engagement within a first hollow cylinder so as to define first and second chambers of the first cylinder and third and fourth chambers of the second cylinder. A piston rod interconnects the pistons. A flow selector alternately directs high-pressure proppant-free fluid to the first chamber and the third chamber so as to act on the pistons, thereby applying pressure to fracking fluid within the second and fourth chambers, respectively, for delivery to the well in alternate power strokes. The faces of the pistons facing the first and third chambers have a smaller effective surface area than the faces towards the second and fourth chambers such that pressure in the fracking fluid remains lower than pressure in the proppant-free fluid.

A double-headed piston type swash plate compressor includes a rotation shaft, a housing, a swash plate, two cylinder bores, a double-headed piston, and two shoes. The double-headed piston includes two shoe holders, a neck, two heads, and two coupling portions. At least one of the two coupling portions includes a load receiving portion. The load receiving portion is configured to receive bending load that is applied from the swash plate to the double-headed piston and acts toward an inner side in the radial direction. The load receiving portion is separated from the wall surface of the cylinder bore when load applied to the double-headed piston is less than a specific threshold value. The load receiving portion abuts against the inner wall of the cylinder bore and receives the bending load when the load applied to the double-headed piston is greater than the specific threshold value.

A pump having two pistons which are parallel and in opposition and are disposed in two, cylindrical, cavities in a pump body, including at least one inlet port and at least one outlet port connected to a rotational port-switching device which can move axially along its rotational axis and is held in abutment in the pump body by a restoring member, in the form of a spring.

A pump having two pistons which are parallel and in opposition and are disposed in two, cylindrical, cavities in a pump body, including at least one inlet port and at least one outlet port connected to a rotational port-switching device which can move axially along its rotational axis and is held in abutment in the pump body by a restoring member, in the form of a spring.

A fluid dispensing device includes a housing and a reciprocating piston fluid pump coupled to the housing. The reciprocating piston fluid pump includes a piston disposed within a cylinder. The piston is configured to pressurize at least one pumping chamber. A motor is coupled to the housing and connected to the reciprocating piston fluid pump to actuate the piston. A wobble assembly connects the motor to the piston of the reciprocating piston fluid pump. A spray tip connected to an outlet of the at least one pumping chamber.

A fluid dispensing device includes a housing and a reciprocating piston fluid pump coupled to the housing. The reciprocating piston fluid pump includes a piston disposed within a cylinder. The piston is configured to pressurize at least one pumping chamber. A motor is coupled to the housing and connected to the reciprocating piston fluid pump to actuate the piston. A wobble assembly connects the motor to the piston of the reciprocating piston fluid pump. A spray tip connected to an outlet of the at least one pumping chamber.