A high-pressure compressor having a hydraulic system and a gas chamber, where the hydraulic system includes a reservoir, connected to a hydraulic fluid chamber by a hydraulic flow path and a pump assembly positioned in the hydraulic flow path, and the compressor furthermore includes a control element controlling the flow of hydraulic fluid in the hydraulic flow path and thereby the pressure in the hydraulic fluid chamber, where the control element and the pump assembly is configured for controlling the pressure of hydraulic fluid in the hydraulic fluid chamber when the compressor is not in operation.

A conveying device for conveying a viscous material from a container includes a follower plate that can be inserted into the container, and a pump by means of which the viscous material can be conveyed through the follower plate. Moreover, a measuring chamber for accommodation of a measuring sample of the viscous material is provided. The measuring chamber includes a closable material inlet opening for this purpose. A closable disposal line leads away from the measuring chamber. Moreover, a closable material return line extends from the measuring chamber via the follower plate into the container. The conveying device also includes a controller that is designed and can be operated appropriately such that it determines the compressibility of each of multiple measuring samples. The controller opens the disposal line or the material return line to the measuring sample present in the measuring chamber as a function of the compressibility thus determined.

A gas booster for increasing a pressure of a gas includes a gas cylinder and a drive. The gas cylinder defines a chamber having an inlet and an outlet. A piston is actuatable within the gas cylinder to draw gas into the chamber through the inlet at a first pressure and to push the gas out of the chamber through the outlet at a second pressure that is higher than the first pressure. The drive includes an electric motor coupled to the piston of the gas cylinder by a mechanical connection to actuate the piston.

In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

A method for determining a current wear (w) of a hydrostatic pump, particularly of a radial piston pump, with a variable-speed drive, where the pump is connected to a fluid passage, in which a fluid is pumped by the pump to create a current actual volume flow in the fluid passage. A current actual volume flow (Q.sub.act) is determined, by measuring the volume flow in the fluid passage at a predetermined drive-vector, a computed volume flow (Q.sub.comp) is determined, by a first computational method, at the predetermined drive-vector, and the current wear (w) of the pump is determined, by a second computational method, which relates the current actual volume flow (Q.sub.act) to the computed volume flow (Q.sub.comp).

A variable positive displacement pump actuator system for a variable positive displacement pump can include a supply line configured to provide a supply pressure, a main pump line configured to provide a pump pressure greater than the supply pressure from the variable positive displacement pump, and at least one electro-hydraulic servo valve (EHSV) in fluid communication with the supply line and the main pump line to receive the supply pressure and the pump pressure. The at least one electro-hydraulic servo valve can be configured to output a first regulated pressure and a second regulated pressure. The system can include a first control line in fluid communication with at least one of the at least one EHSV to receive the first controlled pressure, a second control line in fluid communication with at least one of the at least one EHSV to receive the second controlled pressure, a first hydraulic actuator configured to connect to and/or otherwise actuate a lever arm of the variable positive displacement pump, the first hydraulic actuator in fluid communication with the first control line and the supply line to receive the first control pressure and the supply pressure to control a position of the first hydraulic actuator, and a second hydraulic actuator configured to connect to and/or otherwise actuate the lever arm of the variable positive displacement pump, the second hydraulic actuator in fluid communication with the second control line and the supply line to receive the second control pressure and the supply pressure to control a position of the second hydraulic actuator.

The invention relates to a blood treatment device having at least one metering line which opens into a fluid circuit, wherein a conveyor module is arranged in the metering line and comprises a membrane pump and a valve which is arranged at the pressure side thereof and which can act both as a blocking valve and as a restricting valve.

A diaphragm pump system includes a diaphragm pump and a pressure regulator. The diaphragm pump has a housing having a pumping chamber containing fluid to be pumped, and a transfer chamber adapted to contain hydraulic fluid. A diaphragm is supported by the housing and at least partially defines a pumping chamber side and a transfer chamber side. A driven plunger slides in a reciprocating motion and forcing hydraulic fluid against the diaphragm. A first valve allows hydraulic fluid into the transfer chamber and a second valve allows hydraulic fluid to be removed from the transfer chamber. A hydraulic fluid reservoir is in fluid communication with the transfer chamber. The pressure regulator includes valving that provides a hydraulic fluid pressure above a pumped fluid inlet feed pressure to maintain a proper amount of hydraulic oil in the transfer chamber.

A method of controlling the injection of hydraulic fluid into a high pressure diaphragm compressor having a hydraulic system, the method including: measuring a representation of pressure in a high-pressure part of the hydraulic system of the diaphragm compressor, and maintaining a desired pressure in the high-pressure part of the hydraulic system by adding hydraulic fluid to the high-pressure part of the hydraulic system under the control of a controller on the basis of the measuring of pressure.

A method for determining a current wear (w) of a hydrostatic pump, particularly of a radial piston pump, with a variable-speed drive, where the pump is connected to a fluid passage, in which a fluid is pumped by the pump to create a current actual volume flow in the fluid passage. A current actual volume flow (Q.sub.act) is determined, by measuring the volume flow in the fluid passage at a predetermined drive-vector, a computed volume flow (Q.sub.comp) is determined, by a first computational method, at the predetermined drive-vector, and the current wear (w) of the pump is determined, by a second computational method, which relates the current actual volume flow (Q.sub.act) to the computed volume flow (Q.sub.comp).