| 摘要 |
<p>A drain valve removes liquid from a compressed air system whenever cycling pressure of the system reaches either a preselected high drain pressure or a preselected low drain pressure at an inlet port of the valve. An inlet face of a piston of an adjustable pressure valve assembly within a valve body normally seals the inlet port when there is no pressure. The piston is located within a portion of a central cavity of the valve. The piston's inlet face is of a size which allows the force of the adjustable pressure valve assembly to be overcome by a pre-selected high drain pressure at the inlet port. The area of a vent face on the other side of the piston has a size which, when the vent face is sealing the vent passageway, prevents the force exerted by the adjustable pressure valve assembly from overcoming the pressure of the compressed air system until a pre-selected low drain pressure is reached at the inlet port. In either case, the relative sizes of an opening between an inlet cavity and a vent cavity within which the piston is mounted and a vent orifice, and the area of a dividing member mounted across the piston between the inlet cavity and the vent cavity, allow liquid to be drained by the drain valve until such time as all liquid has been removed and compressed air fills the valve.</p> |
