A compressor device that periodically supplies compressed working gas to a cooling device loses less of the gas by not using rotary valves. The compressor device includes a compressor cylinder, a compensation container and a drive device with an hydraulic cylinder. The compressor cylinder includes a compressor element, such as a piston or membrane, that divides the compressor cylinder into first and second volumes. The first volume contains the gas that is compressed by the compressor element. The hydraulic cylinder has a piston that is coupled to the compressor element. The compensation container contains compensation fluid and is directly connected to the second volume. The compensation container is also connected to the first volume by a gas line with a non-return valve that opens in the direction of the first volume. The drive device allows the compressed gas to be provided at a frequency required for Gifford-McMahon and pulse-tube coolers.

The invention relates to a positive displacement pump 1 for conveying medical fluids, which pump has a pumping chamber 5 and a positive displacement element 15, and to a blood treatment apparatus comprising a positive displacement pump 1. In addition, the invention relates to a method for controlling a positive displacement pump 1 for conveying medical fluids. The positive displacement pump 1 according to the invention has an actuation member 20 in operative connection with the positive displacement element 20 for displacing or deforming the positive displacement element in order to convey the fluid into the pumping chamber or out of the pumping chamber, and a drive device 21 for displacing the actuation member 20. A control unit 14 is provided for to controlling the drive device 21 and an inlet valve 12 and outlet valve 13. The actuation member 20 is in operative connection with the positive displacement element 15 via a working chamber 19 that is filled with gas and has a sealed volume. In order to achieve a high conveying precision, the pressure in the working chamber 5 is kept constant when the positive displacement element 15 is moved.

In a control system for operating a pump, the pump is pneumatically driven to pump hydraulic fluid to pressurize a closed vessel. The control system includes inlet and outlet ports, a pneumatic regulator, a pressure transducer, and control circuitry. The inlet and outlet ports are configured to receive inlet and output outlet pressurized air, respectively. The outlet pressurized air powers the pump. The pneumatic regulator is disposed between the ports, and configured to receive the inlet air and output the outlet air. The pneumatic regulator includes a valve that modulates pneumatic pressure based on a control signal. The pressure transducer provides a hydraulic pressure signal indicative of pressure at the output of the pump. The control circuitry is configured to adjust a parameter of the control signal based on this hydraulic pressure signal, and output the control signal to the pneumatic regulator to indirectly control operation of the pump.

A rotary valve rotated by an arm connected to a piston being driven by the pressurized fluid, either water or air. The orientation of the valve body in the valve housing will direct the fluid in one of two directions to move the piston. The arm of the rotary valve is connected to a cam that rotates a shaft connected to the valve body. Two cam rollers are biased towards the outer surface of the rotating cam member. The cam rollers provide a force to the cam to aid in the changing of the orientation of the valve body. There are two bump outs on the cam that correlate to the end of the piston movement so that the rotary valve does not stop at an end point of the piston stroke. The rotary valve may be is utilized in a chemical dosing or chemical application device that is driven by pressurized fluid.

A system for purifying a treated liquid, including: a treatment module, for treating the liquid and providing a purified liquid, and a residual liquid; and a means for pressurizing said treated liquid to supply said treatment module, including: a master cylinder, driven by a working fluid, and at least slave cylinder, driven by said master cylinder, receiving said treated liquid and supplying it to said treatment module;
a cross section of said master cylinder is greater than a cross section of said slave cylinder so that, a greater pressure is generated on the treated liquid in the slave cylinder; and a means for pre-pressurizing the treated liquid, upstream of the pressurizing means, including: at least one master cylinder, connected to the treatment module, and driven by the residual liquid, and a slave cylinder, containing the treated liquid, driven by said master cylinder.

A system for purifying a treated liquid, including: a treatment module, for treating the liquid and providing a purified liquid, and a residual liquid; and a means for pressurizing said treated liquid to supply said treatment module, including: a master cylinder, driven by a working fluid, and at least slave cylinder, driven by said master cylinder, receiving said treated liquid and supplying it to said treatment module;
a cross section of said master cylinder is greater than a cross section of said slave cylinder so that, a greater pressure is generated on the treated liquid in the slave cylinder; and a means for pre-pressurizing the treated liquid, upstream of the pressurizing means, including: at least one master cylinder, connected to the treatment module, and driven by the residual liquid, and a slave cylinder, containing the treated liquid, driven by said master cylinder.

A follower plate and an apparatus that uses the follower plate to force a viscous material to flow from a storage container. The follower plate includes a cylindrical outer body, a sealing element, and a material saving insert in which a plurality of ribs forms annular concentric slots having a length (L) that runs from the outer edge of the insert to an inner hub. Each slot further exhibits a width (w) that remains substantially the same along its length (L). Each slot further comprises a depth that is variable and tapers along its length (L), such that the depth of the slot approximate to the outer edge (d.sub.o) is less than the depth of the slot approximate to the inner hub (d.sub.i). The width and depth of the slots are configured so that any viscous material that has not been dispensed from the storage container resides within the slots.

A system includes a pump. The pump includes a piston configured to axially reciprocate within a body. The axial movement of the piston activates a first chamber valve and a second chamber valve. The system also includes a main valve configured to direct a flow to the pump to facilitate the axial movement which then transfers a fluid from a reservoir to a spray applicator. The system includes a runaway valve system fluidly coupled to the main valve and configured to detect a runaway state of the pump. The runaway valve system is configured to direct the main valve to stop operation of the pump in response to detection of the runaway state.

A system includes a pump. The pump includes a piston configured to axially reciprocate within a body. The axial movement of the piston activates a first chamber valve and a second chamber valve. The system also includes a main valve configured to direct a flow to the pump to facilitate the axial movement which then transfers a fluid from a reservoir to a spray applicator. The system includes a runaway valve system fluidly coupled to the main valve and configured to detect a runaway state of the pump. The runaway valve system is configured to direct the main valve to stop operation of the pump in response to detection of the runaway state.

A pump assembly. The pump assembly may comprise a motor portion for driving a fluid pumping portion via a piston. The motor portion may comprise: a spool and a spool housing assembly having a spool chamber. The spool may be disposed within the spool chamber. The spool may comprise an upper portion and a lower portion, wherein the diameter of the lower portion is larger than the diameter of the upper portion. The spool may also comprise: (1) two support groove portions for cradling two slide valves and (2) two spool bores, which are in fluid communication with the two slide valves. The piston of the pump assembly may comprise a valve stem having a valve stem bore and valve stem openings. The valve stem openings may be funnel-shaped or may inwardly slope into the valve stem bore to prevent or minimize cutting or shredding of a blown seal.