| 摘要 |
A device for controlling the delivery of a combustible gas to a burner apparatus comprises a main pipe (2) for delivery of the gas in which are disposed a first and a second servovalve (5, 6), respectively in cascade with each other, with respect to the direction of flow of the gas, the servovalves including respective valve seats (5a, 6a) associated with corresponding shut-off means (5b, 6b) with diaphragm control (5c, 6c) for the opening of the seats in opposition to respective resilient return means (5d, 6d), the first and second servovalve (7, 13) comprising a respective first and second control solenoid valve (7, 13) with electromagnetic operating means for controlling the opening/closure of the corresponding servovalve (5, 6), the solenoid valves being arranged to act for opening/closure of pipes of respective servo-assisted control circuits, so as to control indirectly, by way of the diaphragm control, the respective shut-off means (5b, 6b) of the corresponding servovalve (5, 6), the pipes of the control circuit placing the main pipe (2) in fluid communication with respective control chambers (10, 17) of the servovalves, one side of the diaphragms (5c, 6c) of said diaphragm controls being subjected to the pressure existing in the respective control chamber. The intake pipes (8, 9) of the respective control circuits, capable of picking up the pressure signal to be transmitted to the corresponding control chamber (10, 17), are both respectively connected, in fluid communication, with the main pipe (2), upstream of the first servovalve (5). |
