Pulse tube coolers and Gifford-McMahon coolers are used to cool nuclear spin tomographs and cryopumps. To supply cooled working gas, gas compressors and in particular helium compressors are used with rotational or rotary valves. The rate at which compressed helium is introduced into the cooling device and let out again lies in the range of 1 Hz. A problem of conventional screw or piston processors is that oil from the compressor mixes with the working gas and thus contaminates the cooling device. By providing a second compressor stage, a common pump device can be used to pump in both directions, which results in a two-stage compressor device. The working gas is compressed in each flow direction of the working liquid, in one flow direction in the first compressor stage and in the opposite flow direction in the second compressor stage. Thus, the efficiency of the compressor device is improved.

Method, and associated system, computer program and use, of controlling working range of a pump bellows, including maximum limitations such as maximum retracting position and maximum extension position of the bellows, the method comprising the steps of: a) reading at least a first position of a bellows (6′, 6″) in a closed hydraulic loop volume using at least one position sensor (12′, 12″), g) transmitting a first position signal representing the first position to a control system, h) wherein the control system, based on the at least first position signal: c1) determines the position of the bellows (6′, 6″) represented by the at least first position signal, c2) compares the position of the bellows (6′, 6″) with a predetermined bellows position operating range, and c3) if the position is outside the predetermined bellows position operating range, instructs an oil management system valve (16′, 16″) allowing a dual acting pressure boosting liquid partition device (2) to recalibrate the hydraulic fluid volume in the closed hydraulic loop volume to re-establish a hydraulic fluid volume that causes the at least first position to return to a position within the predetermined bellows position operating range.

A compressor includes a stationary housing disposed about a central axis and having a radially inner surface defining a plurality of circumferentially spaced cavities opening into an interior space of the housing. The compressor further includes a plurality of fluid volume control members, each of which is disposed within one of the plurality of cavities and defines a fluid chamber within the cavity sealed relative to the interior space. An eccentric shaft is disposed within the interior space of the housing and configured for rotation about the central axis. A hypocycloid rotor is disposed within the interior space of the housing and supported on the eccentric shaft. The rotor defines a plurality of lobes configured for movement into and out of each cavity responsive to rotation of the shaft to displace the fluid volume control member in each cavity and adjust a volume of each fluid chamber.

A fluid pump is proposed. The fluid pump includes: a housing having an operation space and having connection ports disposed at a side in the operation space to discharge working fluid and suctioning working fluid from the outside; a swash plate coupled to the housing at an opposite side to the connection ports and having an inclined surface on a top facing the operation space; a cylinder block disposed in the operation space to be rotated by a driving shaft and having several cylinder rooms therein that extend in parallel with the driving shaft.

A tubephragm pump includes a tubephragm that has a pump head portion that forms a pump chamber, a driving head that holds the tubephragm and expands and contracts the pump chamber by directly pressing and pulling the pump head portion in a direction intersecting with a transfer direction of a transfer fluid, a driving unit that drives the driving head back and forth in a driving direction to expand and contract the pump chamber, and a control unit that controls the driving unit. The tubephragm is in a flat shape with a cross-sectional shape intersecting with the transfer direction of the transfer fluid of the pump chamber having a length in a direction intersecting with the driving direction longer than a length in the driving direction. A pair of liquid contacting surfaces opposing in the driving direction of the pump chamber move while maintaining a parallel state.

A multistage compressor is disclosed that may include a wobbling member operationally coupled with an external power source. The external power source may drive a nutating motion of the wobbling member. The multistage compressor may further include a plurality of flexible chambers connected to the wobbling member, each flexible chamber including a respective intake passage and a respective discharge passage. The wobbling member may sequentially press down and pull up the plurality of flexible chambers. The multistage compressor may further include a one-way valve in each respective intake passage and gas may be drawn into each flexible chamber through the respective one-way valve of each flexible chamber as the wobbling member pulls up each flexible chamber. The gas may then be compressed to a higher pressure as the wobbling member presses down each flexible chamber and compressed gas may be discharged through the respective discharge passage of each flexible chamber.

The bellows pump device supplies pressurized air to one air chamber of two hermetic air chambers thereby to cause a bellows to perform expansion operation to suck a transport fluid, and supplies pressurized air to the other air chamber thereby to cause the bellows to perform contraction operation to discharge the transport fluid. The bellows pump device includes: an electropneumatic regulator configured to adjust a first air pressure of the pressurized air to be supplied to the one air chamber, and a second air pressure of the pressurized air to be supplied to the other air chamber; and a control unit configured to control the electropneumatic regulator such that, at least at a time point of end of expansion during expansion operation of the bellows, the first air pressure is lower than the second air pressure.

An electric inflator for connecting and inflating an inflatable device includes a shell, a drive motor configured on the axis of the shell, at least one air bag is configured in the shell and around the drive motor, an air outlet of the air bag connected to an inflatable device, and a pressing mechanism connected to an output portion of the drive motor. The air bag is pressed by the pressing mechanism driven by the drive motor for supplying air to the inflatable device. An inner space of the shell can be fully utilized thereby the size of the electric inflator is smaller than before. At the same time, an inner cavity of the air bag can be bigger than before to improve inflating efficiency, which increases portability and practicability of the electric inflator and the inflatable device equipped with the electric inflator.

A bellows pump device includes: a first electropneumatic regulator 51 that adjusts a first air pressure of pressurized air in a first discharge-side air chamber 21A of a first air cylinder unit 27; a second electropneumatic regulator 52 that adjusts a second air pressure of pressurized air in a second discharge-side air chamber 21B of a second air cylinder unit 28; and a control unit 6 that controls the first electropneumatic regulator 51 such that the first air pressure is continuously decreased during a period from a time when a second bellows 14 starts contracting until a first bellows 13 comes into a most contracted state, and controls the second electropneumatic regulator 52 such that the second air pressure is continuously decreased during a period from a time when the first bellows 13 starts contracting until the second bellows 14 comes into a most contracted state.

A diaphragm pump (1) includes a driving body (33) configured to convert a rotation of a crank body (31) into a reciprocal motion and transmit the reciprocal motion to a deformed portion (11) of a diaphragm (7). The driving body (33) includes a shaft portion (36) including a shaft hole (43) in which a driving shaft (32) fixed to the crank body is rotatably fitted. The shaft hole is a non-through hole including an opening-side end (43a) and a closed-side end (43b) each including an inner peripheral surface that contacts the driving shaft over a whole circumference. The shaft portion includes an oil storage (44) opening to a region between the opening-side end and the closed-side end of the shaft hole.