| 摘要 |
A plurality of individually actuatable, bistable, digital valve elements interconnect an upstream chamber and a downstream chamber. Each valve element has a stationary cylindrical cage disposed in the upstream chamber and an axially movable cylindrical plug disposed around the cage. The interior of the cage is open at one end to communicate with the downstream chamber and has a perforated side wall to communicate with the upstream chamber. The resultant areas of the perforations in the side walls of at least some of the respective cages vary in accordance with a geometric progression, and the areas of the open ends of these cages are the same. The plug has ports at one end to equalize the pressure between the plug and the cage. The position of the plug is controlled by a two-stage arrangement. One stage is a piston driven by a fluid from a supply manifold in common with the other valve elements. The other stage is a pilot valve for controlling the fluid applied to the piston. The pilot valves and the common supply manifold are enclosed within a unitary housing.
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