DEVICE FOR AUTOMATIC CHANGE OF PUMP EFFICIENCY AT PERMANENT PRESSURE Russian patent published in 2008 - IPC F04B49/00 

FIELD: engines and pumps.

SUBSTANCE: device is used in a hydro drive of a mechanism for feeding a pit-run borer; the said borer is applied in boring blast holes in rocks of a high degree of nonuniformity. The device consists of case-sleeve with lead-in and outlet channels, movable valve with grooves and base. There are an upper, middle and low conic grooves milled in the valve. A permanent supply of a working flow under pressure is carried through the low groove. A control pressure is supplied through the upper groove. A permanent outlet of drainage is performed through the middle groove. An inlet channel is made in the base and working pressure supply to the end of the valve goes through this inlet channel; the valve, the working pressure supply channel and the conic grooves create the contour facilitating control of pump efficiency, a hydraulic centering and returning the valve into an initial position.

EFFECT: facilitating stability of a fixed pressure and increasing reliability of operation of the device.

2 dwg