RYUTAIATSUSOSOCHI

摘要

PURPOSE:To obviate the wear and damage of slide portions by filling a pressurizing chamber provided between a cylinder and a valve chamber with liquid different from forced fluid in the specific gravity. CONSTITUTION:A pressurizing chamber 5a is provided therein with an elastic diaphragm 21 as pressure responsive body stretched to partition said chamber into the cylinder 19 side A and valve chamber 1 side B. The cylinder side A of the elastic diaphragm 21 is filled with working medium 23 like oil through an oil path 22 of a plunger box 4. The pressurizing chamber 5a of the valve chamber 1 side and a portion of a path 18 are filled with liquid 24 like oil having the specific gravity smaller than that 14 of cement mill or the like and unable to be mixed with the fluid 14. The liquid 24 makes contact with the forced fluid 14 on the way of the path 18. The liquid in the pressurizing chamber 5a does not overflow to the valve chamber 1 side according to a difference in the specific gravity between the forced fluid and the liquid.