A fluid control device includes a piezoelectric pump, a piezoelectric pump, a container, and a control unit. The piezoelectric pumps and are connected in series. The piezoelectric pump is an upstream-side pump, and the piezoelectric pump is a downstream-side pump. The control unit controls driving of the piezoelectric pumps. The control unit makes the driving start timing of the piezoelectric pump on an upstream side earlier than the driving start timing of the piezoelectric pump on a downstream side.

An actuating and sensing module is disclosed and includes a bottom plate, terminals, a control chip, a partition plate, a gas pressure sensor, a thin gas transportation device and a cover plate. The bottom plate includes terminal grooves, a recess, a gas outlet and a gas relief aperture. The terminals are disposed in the terminal grooves. The control chip is disposed in the recess. The partition plate is stacked on the bottom plate and includes an outlet opening in communication with the gas outlet and a pressure relief orifice corresponding to the gas relief aperture. The thin gas transportation device seals the gas outlet and the pressure relief orifice. The cover plate includes an opening passed through by the thin gas transportation device. The gas is transported to the outlet opening by the thin gas transportation device and sensed by the gas pressure sensor disposed in the outlet opening.

An actuating and sensing module is disclosed and includes a bottom plate, terminals, a control chip, a partition plate, a gas pressure sensor, a thin gas transportation device and a cover plate. The bottom plate includes terminal grooves, a recess, a gas outlet and a gas relief aperture. The terminals are disposed in the terminal grooves. The control chip is disposed in the recess. The partition plate is stacked on the bottom plate and includes an outlet opening in communication with the gas outlet and a pressure relief orifice corresponding to the gas relief aperture. The thin gas transportation device seals the gas outlet and the pressure relief orifice. The cover plate includes an opening passed through by the thin gas transportation device. The gas is transported to the outlet opening by the thin gas transportation device and sensed by the gas pressure sensor disposed in the outlet opening.

An inlet valve system (10), as may be used for a cylinder chamber (20) of a compressor, such as a reciprocating compressor, is disclosed. A plurality of inlet valves (250) is movable between an open position and a closed position. The plurality of inlet valves is arranged between an unloader chamber (120) and a cylinder chamber (20) of the compressor. A control valve (270, 270′) is coupled to a controller (300) and is movable between a first position and a second position to close the inlet valves. A check valve (260, 260′) is movable between a first position and a second position to open the inlet valves. The check valve and the control valve are respectively fluidly coupled to a control chamber (252), which is decoupled from any pressure control external to cylinder chamber (20).

A pneumatic pump control system includes a pump chamber having a top end and a bottom end, an air valve coupled to the top end of the pump chamber and configured to be coupled to a pressurized air source, and a pump chamber valve coupled to the bottom end of the pump chamber. In addition, the pneumatic pump control system includes a discharge chamber having a top end and a bottom end, a discharge fitting coupled to the top end of the discharge chamber, a discharge check valve coupled to the bottom end of the discharge chamber in fluid communication with the pump chamber valve, and an inlet check valve in fluid communication with the pump chamber.

A pneumatic pump control system includes a pump chamber having a top end and a bottom end, an air valve coupled to the top end of the pump chamber and configured to be coupled to a pressurized air source, and a pump chamber valve coupled to the bottom end of the pump chamber. In addition, the pneumatic pump control system includes a discharge chamber having a top end and a bottom end, a discharge fitting coupled to the top end of the discharge chamber, a discharge check valve coupled to the bottom end of the discharge chamber in fluid communication with the pump chamber valve, and an inlet check valve in fluid communication with the pump chamber.

The invention relates to a method for deactivating a fuel cell system (10) comprising a jet pump (28) for conveying an anode-side gas flow in a recirculation path (26), wherein the jet pump (28) comprises a metering valve (36) for metering H.sub.2. While the fuel cell system (10) is cooling, a flow passes through a drive nozzle (46) at least once in order to discharge condensed water. The t invention additionally relates to a jet pump (28) comprising a metering valve (36) and to the use of the method in order to deactivate a fuel cell system (10).

Refrigerant compressor for refrigeration systems, comprising an electric motor, at least two cylinder banks and a mechanical performance control unit for activating and deactivating at least one of the cylinder banks in order to activate or deactivate its refrigerant output, wherein, for the purpose of operation in partial performance conditions, the refrigerant compressor is operable in at least two different operating modes, of which each provides an activation or deactivation of the cylinder banks that is different from the other operating modes, wherein associated with the refrigerant compressor is a frequency converter for controlling the speed of the electric motor, wherein associated with the refrigerant compressor is an operating condition controller that, in accordance with a performance request signal supplied to it for operation of the refrigerant compressor in the partial performance condition corresponding to this performance request signal, operates the refrigerant compressor in an operating mode that is selected from at least two different operating modes and at a speed adapted to the selected operating mode, for the purpose of achieving this partial performance condition.

An air compressor apparatus is disclosed that includes an air tank. A first compressor assembly can be fluidly coupled to the air tank, the first compressor assembly including a first head unloader valve. A second compressor assembly can be fluidly coupled to the air tank, the second compressor assembly including a second head unloader valve. A control unit can be electrically coupled to the first and second compressor assemblies, the control unit operable to control the operation of the first and second compressor assemblies. During startup, the first and second air compressor assemblies can be configured to draw less than 20 amps of current combined from a single 120 volt power source. The first and second compressor assemblies can each be dual piston compressor assemblies.

Various embodiments of the present disclosure are directed to reciprocating compressors. In one example embodiment, a reciprocating compressor is disclosed including a cylinder, a piston, at least one suction valve, at least one pressure valve, at least one connection chamber, a sequence valve, a sequence valve control unit, and an unloader. The piston moves back and forth in the cylinder in order to form a compression chamber in the cylinder. The at least one suction valve and the at least one pressure valve are provided on the compression chamber. The at least one connection chamber having a connection chamber volume, which is connected to the compression chamber via at least one overflow opening. The sequence valve opens and closes the at least one overflow opening, and the sequence valve control unit controls the sequence valve. The unloader is actuated by an electrically controllable actuator.