MAINS PRESSURE FLUSHER VALVE

摘要

A mains pressure valve which comprises a main chamber (12) having an inlet chamber (11) for fluid and a discharge chamber (14) for fluid; a piston (17) located in the main chamber (12) which is movable into and out of sealing engagement with the outlet of the main chamber (12) and which defines above it an upper portion (40) of the main chamber (12); a port (35) in the upper portion (40) which permits fluid to flow therethrough; and actuation control (42) associated with the port to regulate the flow of fluid through the port. Upon actuation fluid in the upper portion (40) drains through port (35) allowing piston (17) to rise and mains pressure fluid passes from inlet chamber (11) through main chamber (12) and out discharge chamber (14). Fluid bleeds via flow valve (21) and (22) into upper portion (40) and as port (35) is closed piston (17) closes the valve after a predetermined period.