Experimental study of the magnetic fluid reciprocating seal in vacuum environment

Abstract

To solve the problems of high leakage rate and short service life in vacuum equipment, a magnetic fluid reciprocating seal (MFRS) device was designed. A MFRS vacuum test bench was constructed for testing the leakage rate of seals. The effect of the magnetic fluid (MF) injection volume on the pressure resistance of the seals and the effects of reciprocating speed and reciprocating stroke on the leakage rate and the vacuum resistance of the seals were studied by experimental method. The results show that the optimum MF injection volume should be 2.5 ml, and the ratio of functioning MF injected to seal gap volume is 4.596. When the reciprocating shaft moves at a speed of less than 2.85 mm/s, the leakage rate varies in the order of 10−11 Pa m3/s. With the increase of the reciprocating speed, the vacuum of the sealing chamber first remains unchanged and then increases. With the increase of the reciprocating stroke, the vacuum of the sealing chamber first remains unchanged and then increases. The results of the study are of great significance for the design of reciprocating seals to meet the requirements of vacuum environment.