A system for delivering an amount of fluid medium includes an injector, a delivery catheter and a pulsatile generator. The injector is configured for injecting the fluid medium during an injection cycle. The delivery catheter includes a conduit for delivering the fluid medium. The pulsatile generator is configured to apply a pulsatile force on the fluid medium delivered through the delivery catheter at a pulsation frequency. The pulsatile force is defined by a plurality of duty cycles during the injection cycle, each of the plurality of duty cycles including a first flow level and a second flow level that is lower than the first flow level. The pulsation frequency is 3 or more duty cycles per second.

The present disclosure provides a backflow prevention device, comprising: an inlet chamber comprising at least two ports, in which a first port is used for receiving a fluid; a chamber-separating component comprising a separating member and a relief valve; an outlet chamber separated from the inlet chamber by the separating member; the relief valve being operatively connected with the separating member for opening or closing a drain port of the outlet chamber; wherein the fluid is allowed to be delivered from the outlet chamber only when the relief valve is closed by means of a differential pressure applied on the separating member. Also provided is a dialysis apparatus comprising the backflow prevention device. According to the present disclosure, the backflow prevention device has simple structure, reduced dead space and small sizes and can work reliably.

The invention relates to a hydraulic valve unit for the power or torque regulation comprising a first valve having a control piston displaceably supported in a first valve housing and a second valve coaxially arranged to the first valve and having a pressure piston displaceably supported in a second valve housing. A working pressure applied to a working connection can be reduced to a control pressure applied to a control connection by means of the valve unit in dependence on the position of the control piston. The control piston is preloaded by a setting spring arranged in the first valve. In accordance with the invention, the control piston and the pressure piston are connected to one another with force transmission by an elastic element, with the elastic element being adapted to transmit a force acting on the pressure piston onto the control piston. A first characteristic spring for generating a characteristic for the power or torque regulation is additionally arranged between the control piston and the pressure piston, with the first characteristic spring being adapted to exert a force from a specific displacement of the pressure piston by a first distance onward. The invention further relates to a power regulation system having a valve unit in accordance with the invention and an axial piston machine having such a power regulation system.

A pressure regulating and pressure relief valve, has a valve body defining an inlet port, outlet port, valve seat and pressure relief opening. A pressure regulating plug is displaced during a first portion of a motion from an open position, which provides a continuous flow path from the inlet port to the outlet port, to a closed position in which the plug is closed against the valve seat to obstruct the continuous flow path. A spring biases the plug to the open position. An actuation surface is exposed to a pressure at the outlet port that displaces the plug against the spring bias toward the closed position. Further displacement of the plug beyond the closed position during a second portion of the motion that is beyond a range of the first portion of the motion, opens a relief flow path from the outlet port through the pressure release opening.

A pressure regulating and pressure relief valve, has a valve body defining an inlet port, outlet port, valve seat and pressure relief opening. A pressure regulating plug is displaced during a first portion of a motion from an open position, which provides a continuous flow path from the inlet port to the outlet port, to a closed position in which the plug is closed against the valve seat to obstruct the continuous flow path. A spring biases the plug to the open position. An actuation surface is exposed to a pressure at the outlet port that displaces the plug against the spring bias toward the closed position. Further displacement of the plug beyond the closed position during a second portion of the motion that is beyond a range of the first portion of the motion, opens a relief flow path from the outlet port through the pressure release opening.

A poppet-style check valve comprising a small poppet and a large poppet. When low flow rates are required, the small poppet opens and permits the low flow rate to pass efficiently. When demand for flow increases, the large poppet opens, permitting efficient passage of higher flow rates.

The present disclosure relates to a differential pressure driven burst-pipeline emergency blocking system. The system includes a valve body with flanges on opposite axial ends, a cylindrical valve sleeve connected with the inner wall of a flange end and having a through hole in the valve sleeve wall. The wall of the valve sleeve is in movable fit with a valve spool having a U-shaped section. The working fluid through hole in the valve sleeve is communicated with the inner chamber of the valve body and can be closed by a cylindrical surface of the valve spool. A horizontal push rod is in movable fit with a central hole at the left end of the valve spool, and opposite ends of the horizontal push rod are in movable fit with axial orifices of left and right support seats in the valve body respectively.

Passage forming blocks of a first pilot valve and a second pilot valve each include a supply passage, which opens in a first surface and a second surface and is connected to a valve chamber, a first output passage, which opens in the first surface and are connected to the valve chamber, and a second output passage, which opens in the first surface. Further, the passage forming blocks each include an output passage connecting recess. The output passage connecting recess is provided in a section of the second surface that overlaps with an opening region of the first output passage, which opens in the first surface, and is connected to the second output passage. The first output passage of the first pilot valve is connected to the second output passage of the second pilot valve via the output passage connecting recess of the second pilot valve.

A pressure regulating and pressure relief valve, has a valve body defining an inlet port, outlet port, valve seat and pressure relief opening. A pressure regulating plug is displaced during a first portion of a motion from an open position, which provides a continuous flow path from the inlet port to the outlet port, to a closed position in which the plug is closed against the valve seat to obstruct the continuous flow path. A spring biases the plug to the open position. An actuation surface is exposed to a pressure at the outlet port that displaces the plug against the spring bias toward the closed position. Further displacement of the plug beyond the closed position during a second portion of the motion that is beyond a range of the first portion of the motion, opens a relief flow path from the outlet port through the pressure release opening.

A fluid system of a machine. The fluid system includes a fluid reservoir, a pump coupled to the fluid reservoir, a filter coupled to the pump and a valve assembly. The valve assembly includes a first port, a second port coupled to the first port and to the fluid reservoir, a third port coupled to the first port, and a first check valve positioned between the first port and the second port. The fluid system further includes a second check valve positioned between the filter and the third port.