| 摘要 |
Improvements in seal assembly for use in pressure or vacuum chambers or the like comprising a sealing element which may be selectively placed in sealing condition or retracted to a non-sealing condition, the sealing element having a sealing surface adapted to be urged into contact with a wall member and also a surface including portions against load members which may be loaded to urge the sealing surface into sealing condition or relaxed, and spring unit for continuously urging the sealing element away from sealing condition whereby the sealing element is in fact urged out of sealing condition when the load members are relaxed. |
