HYDRAULIC VALVE GEAR AND HYDRAULIC POSITIVE DISPLACEMENT PUMP Russian patent published in 1997 - IPC

FIELD: pumps for delivery of blood. SUBSTANCE: hydraulic valve gear for two-position control of flow of liquid through channel located between two holes 12 and 15 includes valve seat 17 A with valve member 21 moving for tight engagement with valve seat forming valve chamber 20. Valve chamber 20 is communicated with one of liquid holes 15 through valve seat 17A and is engageable with drive device of valve element which converters pressure of liquid delivered to valve chamber 20 from intakes into force acting on valve element in order to shift it relative to valve seat 17A. According to one version of invention, drive device of valve element includes thrust surface on valve element 21 directed to side from valve seat; this surface forms part of wall of valve chamber 20. Second thrust surface on valve element 21 is directed to opposite side forming chamber 7 which is isolated from valve chamber and passage. Positive-displacement pump includes hydraulic valve gear used as intake valve for control of delivery to chamber 20. EFFECT: enhanced efficiency. 22 cl, 6 dwg