| 摘要 |
A device is provided for controlling a gas supply to a burner, having a draft shut-off device and includes a main gas supply pipe with first and second servovalves therein, which include respective valve seats associated with corresponding shut-off members with diaphragm control for opening the seats in opposition to a resilient return member. A pilot pipe branched from the main pipe supplies a pilot burner. A thermoelectric magnetic safety unit is provided on the main pipe, acting to allow gas to flow towards the pilot burner when the unit is activated. The draft shut-off device includes a corresponding shut-off member movable from and towards a position in which an exhaust pipe is shut off, and a diaphragm-controlled pneumatic actuator of the shut-off member, the diaphragm forming a corresponding control chamber of the shut-off member which is in fluid communication with an auxiliary pipe section branched from the main pipe.
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