Abstract: A pressure regulated electric pump is characterized by a positive displacement double acting reciprocating pump driven by an electric motor through a planetary roller screw. A controller senses the pressure of liquid at an outlet from the pump and varies the speed of the motor in a manner to maintain the pressure substantially constant. At a constant flow demand from the pump the motor is operated at a substantially constant speed. As flow demand rises and fans the instantaneous pump outlet pressure falls and rises. The changing pressure is sensed by the controller which makes incremental changes in the speed of the motor to cause the motor to speed up during a pressure fall and to slow down during a pressure rise, in such manner as to maintain pump outlet pressure substantially constant.

Abstract: A high pressure hydraulic diaphragm pump having a pressure chamber on one side of a diaphragm and a fluid delivery chamber on the other side of the diaphragm with a reciprocating piston assembly including a piston member being provided for pressurizing the hydraulic fluid in the pressure chamber and having the pressure chamber connected with a pressure regulator which maintains the desired discharge pressure of the fluid and in which the piston assembly is combined with a diaphragm positioning mechanism for maintaining the diaphragm at a desired position relative to the piston member so as to assure full stroke of the diaphragm during normal operation of the pump.

Abstract: A variable displacement compressor includes a gas passage for connecting a discharge chamber with a crank chamber. The control valve is located in the gas passage to control the pressure in the crank chamber. The control valve has a valve hole and a valve chamber located in the gas passage. A valve body is located in the valve chamber to adjust the opening size of the valve hole. A solenoid has a plunger and a plunger chamber for accommodating the plunger. A rod is located between the plunger and the valve body to transmit the movement of the plunger to the valve body. When the solenoid is de-excited, the bottom end face of the plunger abuts against the inner bottom wall of the plunger chamber. A plurality of grooves are provided on the bottom end face of the plunger and extend radially. The grooves define recessed passages between the bottom end face of the plunger and the inner bottom wall of the plunger chamber to prevent the bottom end face from adhering to the inner bottom wall.

Abstract: A two-cylinder air compressor has a motor with a through drive shaft. Identical housings are provided at each end of a cylindrical spacer sleeve that surrounds the motor. The housings include cylinder housing extensions each of which mounts a cylinder sleeve, a valve plate, and a head. The heads are part of a one-piece cylinder head member. Wobble pistons are mounted on each end of the motor shaft and operate in the cylinder sleeves. The cylinder sleeves rest on a floor in the housing which has integrally formed passages for cooling air to circulate around the cylinder sleeves. The one-piece cylinder head member includes integral tubes connecting the heads. The integral tubes span the distance between the heads and are spaced from the outside of the spacer. The housings may be joined by through bolts or without bolts by press fitting the bearings in the housing, press fitting the housings to the spacer sleeve, and press fitting the motor shaft into the bearings.