| 摘要 |
PURPOSE:To control the liquid pressure with high accuracy within an optical pressure range in a pressure load test, etc., by an interlocking operation between a single-acting piston which increases and decreases the liquid pressure and a hydraulic actuator. CONSTITUTION:A system is first pressurized totally up to a level P2 by a pressure source 1. Thus a single-acting piston 5 moves to the left side of a cylinder 4. Then the supply of the source 1 is stopped and a pressure setting device 10 is actuated. Thus a piston 6b of a hydraulic actuator 6 moves to the right from the left and therefore the piston 5 moves to the right by the same amount as the piston 6. Then the liquid pressure of a liquid pressure line 3 increases. An internal load part 2 is pressurized up to a level P1 and kept there. When a certain holding time passes, the piston 5 is moved to the left from the right. Then the pressure of the part 2 is reduced down to the level P2. This cycle is repeated for repetition of the pressure variance. |
