Surge Absorption by Accumulator : Study in the Case of Air Content in Oil

Abstract

In the hydraulic system with pressure source cylinders are in many cases operated by opening an electro-magnetic valve.In this case, when switching time of the valve is short, a surge wave is generated and it damages the equipment.The author investigated the method of surge absorption by means of acumulators.In a hydraulic system, mixing of air into oil happens easily, and surge pressure is influenced considerably by it.By theoretical and experimental study, the author clarified that surge increase resulted from the fact that the oil column, stiffened by the mixture of air into oil, took on the characteristic of a hard spring.Supposing that the inertia of the cylinder is large enough, the hydraulic system is restricted to the fixed end condition.