| 摘要 |
A flame failure device has a hollow, tubular, heat-resistant, temperature sensitive member to be directly heated by a flame and so arranged that the member will expand or contract along a generally rectilinear axis as it is heated or cooled. The temperature-sensitive member is connected to a mount in a manner which permits or permitted at least initial adjustment of the relative position of the mount and temperature-sensitive element along the generally rectilinear axis and has an abutment which will move relative to the mount as the temperature-sensitive member is heated or cooled. A main valve for controlling supply of fuel to a burner has a fuel inlet, a fuel outlet, a chamber having a diaphragm defining a wall of the chamber, a main-valve member operatively connected to the diaphragm and movable therewith, and a supply passage for restricted fuel flow to the chamber. A pilot valve is connected to the chamber of the main valve having means for venting gas flowing therethrough from the chamber, for controlling opening and closing of the main valve and has a first valve member fixed relative to the mount and spaced from the abutment by a distance which can be or has been adjusted by means of the connection between the temperature-sensitive member and the mount and which varies as the temperature-sensitive member is heated or cooled, and a second valve member movable relative to the fixed valve member and operated by elongate means arranged in the temperature sensitive member. The elongate means and movable valve member are arranged to move under the influence of resilient means so as to close the pilot valve when the temperature-sensitive member is heated and by engagement between the abutment and elongate means to open the pilot valve on cooling of the temperature-sensitive member. The main valve is arranged to open when the pilot valve is closed and to close when the pilot valve is open.
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