| 摘要 |
903,544. Valves. ROBERTSHAW-FULTON CONTROLS CO. April 10, 1959 [Aug. 22, 1958], No. 12258/59. Class 135. A fluid-flow control device comprises a thermal means 102 having an operative connection with a valve 24 via a snap-action device 48 and a spring means 106 between the thermal element and the snap-action device which is deflectable to a loaded condition when the snapaction device is moved to its over-centre position and operable to transmit the spring load to the snap-action device as the latter moves past its over-centre position. An armature 44 is first set against an electromagnet 37 and held there when a pilot burner is ignited. When this burner goes out the armature is released and a spring 45 closes valve 24. With temperature increase the bellows 102 expands and deflects the peripheries of the disc springs 114, 108 until the spring load acting through button 58 and thrust disc 56 causes the centre of the trigger disc 52 to snap upwards and allow spring 47 to close valve 24. The valve is opened, on cooling of the bellows feeler, by the clicker disc pushing the valve through a tubular member 74 containing a spring-loaded override plunger 80. Damage to the bellows 102 is prevented by the casing 84 carrying the temperature setting knob 123 being secured to the valve housing via springs 90 loaded between bolts 86 and flanges 88 on the part 84.
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