An electroproportionally controlled differential pressure valve cartridge includes actuation and tank ports on an outer circumference, and a pump port on a face-side. A spring preloads a piston into a position that relieves pressure from the actuation port to the tank port. A current increase through an electromagnet opposite the pump port and a pressure increase at the pump port counter the spring to open a connection from the pump port to the actuation port. A concentric opening extends from the pump port to a first piston surface. A duct extends from the first piston surface to a pump chamber. A further duct extends from the pump port to a spring chamber between the pump chamber and electromagnet. In the spring chamber, pressure over a second piston surface counters pressure over the first piston surface.

A method for detecting a blocked valve of a coolant compressor including a drive unit and a piston-cylinder unit for cyclical compression of a coolant, wherein the drive unit has an electric motor for driving the piston-cylinder unit, monitors the speed () of the electric motor. A maximum speed (.sub.max) of the electric motor is initially detected, and the following steps are carried out, as long as the speed () of the electric motor substantially corresponds to the maximum speed (.sub.max): determining a maximum value X.sub.max of a monitoring parameter (I, T) of the coolant compressor (1); determining a value X.sub.t1 of the monitoring parameter (I, T) after a first time period (t1) after determining the maximum value X.sub.max; detecting a blocked valve if X.sub.t1 is less than X.sub.max and (X.sub.maxX.sub.t1)/X.sub.max.sub.X applies, wherein .sub.X is predetermined.

A hydraulic pump includes a work port configured to supply fluid to a hydraulic tool. A high-flow piston supplies fluid along a first flow path to the work port and plurality of high-pressure pistons supplies fluid along a second flow path to the work port. An unloading valve is positioned along the first flow path and actuates from an open state to a closed state when a pressure level of the fluid in the second flow path exceeds a first threshold pressure. A controller allows a user to select a mode of operation. The controller sets a second threshold pressure of the hydraulic pump based on the selected mode of operation, and the second threshold pressure corresponds to an end operation of the hydraulic tool.

A slurry injection system has a plurality of slurry valves fluidically coupled to first and second elongated tanks. In the first state, the slurry valves communicate high pressure slurry from the second volume to a site and communicate low pressure slurry to the fourth volume. In the second state, the slurry valves communicate low pressure slurry to the second volume and high pressure slurry from the fourth volume to the slurry injection site and in the intermediate state communicating high pressure slurry simultaneously from the first elongated tank and the second elongated tank to the slurry injection site. In the first state clear fluid valves fluidically communicate high pressure clear fluid to the first volume and low pressure clear fluid from the third volume and, in a second state, communicate low pressure clear fluid from the first volume and high pressure clear fluid to the third volume.

A breast pump system includes a solenoid valve and a power source. The power source is arranged to supply electrical power to the solenoid valve so as enable the solenoid valve to move between first and second positions. The breast pump system also includes a controller configured to detect a change in inductance of the solenoid valve that is indicative of the solenoid valve moving from first to second position and a control action in which the vacuum pump is stopped.

A frac pump valve seat assembly includes a seat body and a wiper seal. The seat assembly is configured to mitigate the risk of fluid end erosion in the valve seating area by automatically clearing or wiping the mating surface of the fluid end at the time of installation. The wiper seal is located at a lower portion of the seat body and is designed to interface therewith the mating surface of the fluid end. Upon installation, the wiper seal scrapes or cleans the mating surface of propellants, sand, and other contaminants that may remain after initial cleaning. The contact surface of the seat body is optionally further reinforced with material implants with greater hardness than the material of the seat body.

A power end frame assembly for a reciprocating pump that includes a first and second end plate segment each including annular bearing support surfaces configured to support a crankshaft bearing assembly. At least one middle plate segment is disposed between the first and second end plate segments and includes an annular bearing support surface configured to support a crankshaft bearing assembly. The annular bearing support surfaces of the first and second end plate segments and the at least one middle plate segment each have a diameter and are coaxially aligned. The diameter of at least one of the first and second end plate segments is different from the diameter of the at least one middle plate segment to facilitate insertion and removal of the crankshaft bearing assembly from the power end frame assembly.

An apparatus and method for sensing the position of a piston in a valve in a gas compressor or the position of a piston in a free piston engine. The apparatus includes a plurality of valve sensors, a plurality of magnets, and a plurality of valve sense modules coupled to the valve sensors and a controller coupled to the plurality of valve sense modules. The method includes processing information received from the valve sensors to determine the linear position of the valves in the gas compressor or a piston in a free piston engine.

A slurry injection system has a plurality of slurry valves fluidically coupled to first and second elongated tanks. In the first state, the slurry valves communicate high pressure slurry from the second volume to a site and communicate low pressure slurry to the fourth volume. In the second state, the slurry valves communicate low pressure slurry to the second volume and high pressure slurry from the fourth volume to the slurry injection site and in the intermediate state communicating high pressure slurry simultaneously from the first elongated tank and the second elongated tank to the slurry injection site. In the first state clear fluid valves fluidically communicate high pressure clear fluid to the first volume and low pressure clear fluid from the third volume and, in a second state, communicate low pressure clear fluid from the first volume and high pressure clear fluid to the third volume.

The present invention relates to a reciprocating compressor able to operate with two separate pressure suction lines provided with a suction valves arrangement and, more particularly, to a suction valves arrangement whose suction valves have different thicknesses. In particular, at least one semi-commanded suction valve has a thickness greater than the thickness of at least one automatic suction valve. The present invention belongs to the field of fluid compressors.