GB1098811A - Improvements in timers or safety cut-outs for fuel-burning appliances - Google Patents

Abstract

1,098,811. Valves. SEEMARK SWITCHES Ltd. July 17, 1964 [July 19, 1963], No. 28714/63. Addition to 981,751. Heading F2V. [Also in Division F4] A timer or safety cutout for a gas burner comprises an actuator which operates a valve (not shown) to shut off the supply of gas to the burner after it has been rotated a predetermined amount by a spring- driven wheel 11 whose movement is controlled in response to the oscillation of a heat conducting plate 19. The plate 19 has a bent portion 22 and divided legs 21 and is pivotally mounted at 23 on a plate 13. The legs 21 are urged into contact with a bi-metallic strip 14 when the strip is cold, by a spring. The strip 14 is mounted in a sling 15 and a screw adjusts the end pressure exerted by the sling on the ends of the strip 14. The strip carries a shaft which pivotally supports a double-pawl escapement piece, operatively associated with the teeth of the wheel 11, and an arm 36 having an end 38 engaging the plate 19. In operation the wheel 11 is rotated to wind up its drive spring and heat is applied to the end 22 of the plate 19. Heat is conducted to the strip 14 which " snaps " into an outwardly bowed position and pawls then allow the wheel 11 to rotate a half tooth-pitch distance. Arm 36 also moves the plate 19 out of contact with the flame and strip 14 " snaps " back on cooling to allow the wheel 11 to rotate a further half-pitch and the plate 19 to contact the flame. The cycle is repeated until the actuator connected to wheel 11 rotates sufficiently to close the gas supply valve. The device may be used to control oil or solid fuel appliances with a heated plate replacing the burner.