| 摘要 |
A gas flow control device including a body means defining an inlet, an outlet and a gas flow passage therebetween a main valve disposed in the passage and comprising a primary valve movable between a closed position that prevents flow through the passage and an open position that permits flow therethrough; a primary diaphragm operably connected to the primary valve and supported by the body means, the primary diaphragm defining within the body and separating a primary reference chamber from a primary regulator chamber located in the passage and the pressure in the primary reference chamber exerting a force tending to open the primary valve; and a primary bias means biasing the primary valve toward its open position. Also included in the device is a secondary valve disposed in the passage between the primary valve and the outlet, the secondary valve movable between a closed position that prevents flow through the passage and an open position that permits flow therethrough; a secondary diaphragm operably connected to the secondary valve and supported by the body, the secondary diaphragm defining with the body and separating a secondary reference chamber from a secondary regulator chamber located in the passage and the pressure in the secondary regulator chamber exerting a force tending to close the secondary valve; a secondary bias means biasing the secondary valve toward the open position and a control passage providing communication between the primary reference chamber and the outlet.
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