Valves

A valve has a pressure chamber within its housing for remote operation. A stem in the housing has axial passages for power fluid and for cleaning liquid. The valve member is a sleeve, biased closed, which engages a movable seat which is resiliently supported. Leakage around the seals between the sleeve and the stem and between the sleeve and the housing is received in chambers and drained away from the housing to prevent mixing of the cleaning liquid and the processing liquids.