HYDRAULIC PUMP UNIT Russian patent published in 2012 - IPC F04B47/08 F04B9/10 

FIELD: engines and pumps.

SUBSTANCE: working fluid is fed by donkey pump to main pump and discharged therefrom via sole branch pipe. Note here that flow reversal is effected by working fluid with the help of hydraulic control valve. Slide valve of the latter is made up of safety valve, accumulator and reversing element. The latter is made up of barrel fitted on safety valve body to axially displace thereon to communicate main pump with slide valve piston chamber and isolate it therefrom. Slide valve piston chamber is communicated with accumulator working chamber via safety valve orifice. Safety valve body is provided with channels to feed working fluid into reversing element chamber and to discharge it therefrom and to discharge working fluid from slide valve piston chamber.

EFFECT: expanded operating performances, simplified design, higher reliability and efficiency.

8 dwg, 2 cl