Patent GB-623420-A (GB)
Title: Improvements relating to flame or temperature detector means for combustion apparatus
IPC: G05D23/12
Filed: 1946-10-28
Abstract: 623,420. Temperature - responsive actuating-elements. HAMMOND, C. F., and SHACKLETON, W. Oct. 28, 1946, No. 31912. [Class 64(ii)] [Also in Group XXXVII] Flame or temperature detector means for combustion apparatus comprises a fluid-filled temperature detector device which is inserted into the combustion zone of the apparatus and means operative to cause the detector device to withdraw from the combustion zone as the fluid expands due to the combustion heat, the detector device restoring itself to its initial setting upon failure of combustion. The retractile and return movement may be applied for effecting switch or relay operations for the actuation of burner controls, indicator or alarm devices and the like. In the form shown, Fig. 1, the temperature responsive element comprises a liquidfilled brass or other metal tube 1 and bulb 2, and a ram 5 sliding within a cylinder 4 which carries a head 11 recessed at 13 for the pivotal mounting at 10 of two levers 7 which have short inner arms each terminating in rounded head or roller 14 on which bears a spring loaded pad, the long outer arms of the levers each having an anti-friction roller 8 which bears on a horizontal surface 9. The head 11 is slidably mounted in a casing 16 to which are fixed shrouds 18 carrying the bearing surfaces 9. As the pressure in the bulb 2 increases with a rise in temperature in the combustion apparatus the ram 5 is lifted and through an associated rod 19 raises the short arm of the levers 7 which causes first the outer ends 8 of the lever to bear upon the fixed surface 9 and then the cylinder 4 to rise, carrying the tube 1 and bulb 2 out of the hot zone. If the combustion flame fails, the cooling of the bulb 2 and consequent drop of pressure therein will permit the return of the parts to their initial setting. A rod 21 acts as an indicator. In another form, in which a uniform relation between the withdrawal movement and the movement of the ram within the cylinder is desired, toothed segments riding on racks may replace or be incorporated in the levers 7 a bellows re-placing the ram. In a modification, the toothed segments may be replaced by grooved segments and associated flexible members such as cords, chains or ribbons attached at one end of the lower end of the grooves and at the other end to the casing. Fig. 5 shows the invention applied to a snap action switch 60 pivoted at 61 and having a throw-over cam plate 63 extending at one side of the pivot. Pivotally mounted on a lug 68 projecting from the aforementioned extension 42 is an arm 64 having a cylindrical tip or roller 65 bearing on the cam plate 63 under the action of a light coil spring 66. A retractile movement of the bellows chamber 31 causes the roller 65 to ride up the cam plate and on passing the nose 67 to snap over the top thereof and to cause a snap operation of the switch 60. In another form, (see Fig. 9, not shown), the invention is applied to a submerged combustion or like burner. The temperature detector means extends through the gas or air passage of the burners and into the combustion chamber and is withdrawn into said passage on failure of combustion. The apparatus may also be mounted in horizontal and inclined positions and the retractile and return movements may have rollers or other anti-friction devices incorporated therein. Springs may be provided to assist the return movement.