| 摘要 |
PURPOSE:To substantially reduce the minimum flow of gas by providing a bypass in parallel with a gas control passageway having a gas pressure proportional valve, by providing the bypass with a bypass nozzle deciding the minimum flow and a gas pressure adjuster, and by joining the flows of gas before the main nozzle. CONSTITUTION:Primary gas supplied under a pressure P1 is controlled by a gas pressure proportional valve 7 in a main passageway 6 and then supplied to a main nozzle 8. Besides this, a bypass 9 is provided in parallel with the main passageway 6 with the entry of the bypass 9 joined with the primary passageway to the gas pressure control valve 7 and the exit joined with the main passageway 6 before the main nozzle 8. When the electric current I passed to the gas pressure proportional valve 7 is shut off, the gas flows only through the bypass 9 so that the minimum flow of gas passed through a bypass nozzle 10 after pressure adjustment by a gas pressure adjuster 11 is all that is supplied to the main nozzle 8. This constitution enables reducing the minimum flow of gas considerably and it is prevented for the indoor temperature to rise beyond a specified point. |
