A method of testing a unit pump system performance is disclosed. In one embodiment of the present disclosure, the method of testing a unit pump system performance determines if mechanical and/or electrical stability of a control valve of the unit pump system are achieved before measuring an output injection volume variation.

The present invention provides a low-cost detachment determining device capable of determining whether or not an electromagnetic valve-equipped device has been detached. The detachment determining device determines whether or not at least a part of an electromagnetic valve-equipped device included in an industrial machine, such as a construction machine or an industrial vehicle, has been detached from the industrial machine, the electromagnetic valve-equipped device being a hydraulic device equipped with an electromagnetic valve. The detachment determining device includes: an electrical characteristic detecting portion configured to output a detection signal to the electromagnetic valve-equipped device and detect an electrical characteristic of the electromagnetic valve-equipped device based on the detection signal; and a detachment determining portion configured to determine, based on a plurality of electrical characteristics detected at different time points by the electrical characteristic detecting portion, whether or not at least a part of the electromagnetic valve-equipped device has been detached.

A pump device for a cooling circuit of an internal combustion engine of a commercial or motor vehicle includes two electric pumps in parallel, each of which includes a switchable backflow valve in a suction line, so that the electric pumps can be operated selectively individually or in parallel.

Provided is a metal diaphragm that can be easily processed and manufactured at low cost. Therefore, a metal diaphragm (91, 92) of the present invention is configured such that a curvature radius r1 of a first curved portion 911 located on the outermost side in the radial direction (outer side in the left-right direction in FIG. 5) is minimized among a flange portion (91a, 92a) and curved portions (911, 912) that are located on the radially inner side of the flange portion (91a, 92a) and curved from the flange portion (91a, 92a) to one side (upper side in FIG. 5).

A closed-loop hydraulic circuit includes a piston chamber housing a piston rod and a ram piston coupled to an end of the piston rod, and a pump in fluid communication with the piston chamber at first and second hydraulic ports. Pumping a hydraulic fluid to the first hydraulic port causes a forward stroke of the ram piston and the piston rod, and pumping the hydraulic fluid to the second hydraulic port causes a return stroke of the ram piston and the piston rod within the piston chamber. An accumulator is in fluid communication with the pump and the piston chamber, and a 3-2 valve is actuatable between a first position, where pressurized hydraulic fluid is conveyed from the accumulator to the pump during the forward stroke, and a second position, where excess hydraulic fluid is conveyed from the first hydraulic port to the accumulator during the return stroke.

A micro-pneumatic control unit comprising a plurality of control channels for generating the control pressures in a pneumatically actuated multi-channel coating head for coating components with a coating agent, a control channel being characterized by a valve element comprising a valve bore in a valve plate and a diaphragm layer which is below the valve plate and is configured as a diaphragm closing element in the region of the valve bore, the shape of which diaphragm closing element defined by recesses positioned laterally with respect to the valve bore, by a micro-actuator having a plunger that actuates the diaphragm closing element through the valve bore such that the valve element opens, by a second micro-pneumatic element connected in series with the valve element, the control pressure developing and a cavity located at the connection node thereof, which cavity is connected to at least one pneumatically operated coating agent ejector, and by a pneumatic pressurization of the micro-pneumatic control unit, which is directed such that, with respect to the valve element, there is a pressure gradient from the diaphragm closing element to the valve bore in the valve plate.

An object is displaced alternately in opposite directions, using a hydraulic power unit having a rotatable body which includes the shaft of a hydraulic machine having electronically commutated valves. A motor drives the rotatable body. The hydraulic machine drives an actuator to displace the object in use. Energy is transformed from rotational kinetic energy of the rotatable body to elastic strain energy or elastic strain and gravitational potential energy of the object during a pumping phase and rotation of the rotatable body slows, but does not change direction. The potential energy then drives the hydraulic machine to motor and the rotatable shaft speeds up again, storing rotational kinetic energy. The displacement of the hydraulic machine is controlled throughout to match a time varying demand taking into account the varying speed of rotation of the rotatable shaft. The motor provides energy to compensate for losses and the process can repeat cyclically.

A high-pressure pump has a metering valve and a valve stopper. The stopper has a regulation portion which an end surface of the valve is brought into contact with. An outer diameter of the regulation portion is equal to an outer diameter of the outer peripheral surface of the valve. A cylindrical sleeve is disposed around the regulation portion. When the end surface of the valve is in contact with the regulation portion, the sleeve covers a tapered surface of the valve.

Various embodiments include methods for operating a high-pressure pump comprising: driving a piston arranged in a compression chamber with a motor shaft; during movement of the piston toward the top dead center, closing the inlet valve so the fluid is then delivered by the piston through an outlet valve; applying a coil current to an electromagnet used to close the inlet valve during and/or after overshooting the top dead center; detecting a start time at which the coil current, on account of starting of an opening movement of the inlet valve, fulfills a predetermined change criterion; labelling a dead center rotation position of the motor shaft at which the piston is at the top dead center based at least in part on the ascertained start time; and adjusting operation of the pump based on the identified dead center rotation position.

A measurement of the pressure of hydraulic fluid in a fluid working machine can be determined from the timing of the movement of valves which selectively seal a working chamber of cyclically varying volume from a fluid gallery. The timing of opening of a low pressure valve, to connect a working chamber to a low pressure fluid gallery, following the closure of a high pressure valve to seal a working chamber can be used to estimate the pressure in the high pressure fluid gallery at the moment of closure of the high pressure valve.