Abstract: A fluid pump unit having a pump, a driving motor which may be air-cooled and various system components which require a cooling air stream includes a fan which is located between the motor and the pump approximately at the midpoint of the cooling air flow route. The air flow route is arranged to be as long as possible and is provided with sharp angular bends and sound-deadening barriers to limit noise transmission to the exterior of the housing. Air-cooled system elements are located between the fan and housing exterior to act as noise deadeners and further reduce noise transmission.

Abstract: A method in which automatic selection of the mode of operation for a compressor unit is achieved and is dependent on the conditions under which the compressor unit is operated. Depending on the existing compressed air demand and the time sequence thereof, the compressor unit operates in a continuous mode, an intermittent mode, or a regulated mode. During continuous mode operation, the compressor intake is either opened or closed so that the compressor unit operates respectively under zero load, when a minimum pressure condition exists, or full load, when a maximum pressure condition exists. During intermittent mode operation, the compressor unit is turned off when a maximum pressure condition exists and is turned on when a minimum pressure condition exists. During regulated mode operation, the compressor intake is varied between open and closed positions depending on output pressure.

Abstract: A rotary gas compressor or expansion motor with a housing having circumferentially spaced inlet and outlet ports. An outer cage or sleeve rotor has alternate slots and teeth. An inner lobe rotor has lobes which mesh with the slots of the cage rotor as the two rotate. The space between the two rotors is filled with a crescent-shaped housing member. The slots, teeth and lobes of the rotors are helical.

Abstract: A compressor intake throttle valve is positioned in accordance with the inlet suction of the compressor, regulating the volume of inlet air in accordance with the load on the compressor. A relief valve connected with the compressor outlet opens when the compressor outlet pressure exceeds a set value and vents compressed air to the compressor intake passage at a point between the throttle valve and the compressor inlet, closing the throttle valve.

Abstract: A multiple function valve for a compressor cooling liquid system. A cylindrical valve housing has an inlet at one end and an outlet at the other with a flow passage therethrough. A thermal valve controls the liquid flow between the inlet and outlet and diverts liquid to a heat exchanger connected with ports in the valve body. A pressure responsive on-off valve is located between the thermal valve and the outlet. A filter is connected between the inlet and the thermal valve.