HIGH HYDRAULIC PRESSURE GENERATOR

PURPOSE:To control the extent of hydraulic pressure accurately in miniaturizing a device and eliminating an electric noise by installing a boost pump, pressurizing a liquid with a piston displacing according to gas pressure, and a means controlling this gas pressure according to an electric signal, respectively. CONSTITUTION:High pressure gas in a gas accumulator 5 is regulated into constant pressure in a pressure regulating valve 12 by way of owing two manual on-off valves 10 and 11, while it leads to a gas chamber 6a by way of opening a solenoid valve 13. In this constitution, a piston 7 is displaced according to gas pressure in this gas chamber 6a, and a liquid to be charged to a liquid chamber 6b from a charging port 19 is pressurized, whereby a test piece 17 is pressurized. In addition, when another solenoid valve 20 is opened, the gas pressure in the gas chamber 6a goes down. A unit controller 22 outputs an electric signal in conformity with a program on the basis of a command signal from the outside and each input signal out of both sensors 23 and 24, opening or closing both these solenoid valves 13 and 20 and varying the gas pressure in the gas chamber 6a, and thereby hydraulic pressure value in the liquid chamber 6b and hydraulic varying velocity are all controlled. Consequently miniaturization is achievable and any electric noise is eliminable and fully autoamtic control can be done in an accurate manner.