| 摘要 |
A valve body has a chamber in which a ball is located, the chamber portion occupied by the ball being exposed to a working port that is to be switched between a high pressure inlet port and an exhaust port. The ball is located between valve seats, and a diaphragm at the end of the chamber portion to which one port is connected is movable with the ball via an internal pin and external strap arrangement to move the ball against one or the other of the valve seats. In an arrangement wherein the one chamber is exposed to the high pressure inlet port, in the closed position of the valve the area of the diaphragm is only slightly greater than that of the ball circumscribed by the adjacent valve seat. In the open position, the area of the diaphragm is only slightly less than that of the ball circumscribed by the other valve seat. Via a pressure responsive device coupled to the external strap, and operable with a snap action disc spring, a few ounces of force applied to the strap will move the ball against one or the other of the valve seats, and the ball remains in such position and effects communication between the working port and either the high pressure inlet port or the exhaust port. A switch is also actuated in one embodiment. In other arrangements, diaphragm to valve seat area parameters are selected so the ball is normally seated against one valve seat and is moved via the strap against the other valve seat. In such monostable arrangements, the ball and diaphragm are automatically returned to the normal position when the force on the strap is removed.
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