PROBLEM TO BE SOLVED: To provide a high pressure reciprocating pump having an improved arrangement for synchronizing a gradient generator by making its recompression volume equal to that of a high pressure pump.
SOLUTION: The high pressure reciprocating pump is structured so that its check valve remains closed in the initial period of the pumping stroke of the first piston in which the fluid is compressed with a finite modulus of elasticity by volume and the second piston shares all flow at a fixed rotating speed. If then the pressure in the cylinder of the first piston once reaches the pressure of exhaustion and a discharge check valve is opened, the control system is changed over into the constant pressure control mode so as to maintain the rate of flow to the fixed value. When the discharge check valve of the second piston is closed and the pump control returns to the fixed rotating speed, the constant pressure control is switched off again. Determination of the angular displacement for making valid the changing-over of the control modes is executed by monitoring the discharge pressure and accommodating the value of angular displacement in which the first-grade time differential of the pressure changes remarkably.
COPYRIGHT: (C)2004,JPO&NCIPI