| 摘要 |
A pressure-actuated valve of the type used in the fuel systems of gas turbine engines and the like combines the functions of check valve and metering valve in a housing forming a single assembly. A movable valve actuator is slidably movable along a central axis within the housing, The actuator has two spaced-apart valve faces that cooperate with two spaced apart valve seats mounted to the housing. One of the valve-seat/valve-face combinations controls flow through a primary outlet port from the housing, and the second combination controls fluid flow through a separate, secondary outlet. The second valve combination includes telescopically mating inner and outer wall surfaces having a metering passage in the outer wall characterized by a transverse cross-section that varies from a minimum to a maximum at its opposite ends. As the inner and outlet wall surfaces move relative to each other, the exposed cross-section of the metering passage increases to permit increased flow through the valve. The second valve combination opens in sequence, subsequent to opening of the primary combination, as the actuator is displaced along its axis. Biasing springs having differing spring rates apply biasing force to the actuator along its path. Hydraulic pressure-receiving surfaces on the actuator are exposed to pressurized fluid flowing through the valve to generate hydraulic forces for moving the valve actuator against the biasing force of the springs.
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