| 摘要 |
Apparatus and a method for controlling the flow of a fluid to a fluid-actuated system. The system is controlled by a sensor which senses a variable characteristic of the system, such as the air temperature. The apparatus includes a pair of solenoid valves, one valve being set to deliver a first volume of fluid per unit time and the other valve being set to deliver a second volume of fluid per unit time. The solenoid coil of one of the valves responds to the actuation and de-actuation of the sensor. The second valve has a solenoid coil controlled by a pair of switches. One of the switches is responsive to a first timing signal and the second switch is responsive to a second timing signal. One of the switches allows the second valve to be open for a first time interval during which the first valve is open; thereafter, the second valve is closed. The other switch of said pair causes the second valve to be opened after a second time interval following the end of the first time interval and to remain open so long as the sensor has not been de-actuated. Both valves are closed when the sensor is de-actuated.
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