Improvements in or relating to thermostatically-controlled electric heating equipment

摘要

586,924. Thermal switches. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and ROSEBY, P. N. April 25, 1944, No. 7643. [Class 38 (v)] A thermal switch for protecting boiling plates having a loading such that dangerous temperature-rises may occur when the plate is energized but not in use, has a bimetal strip 18 heated by radiation from the underside of the plate 10 acting through apertures 20, 21 in the base 13. The strip is connected at its free end, through a deadcentre spring 26 passing through a hole in a bracket 28, to a U-shaped contact blade 29 resting in V-notches in the bracket 28. Radiant heat passing through the preferably-adjustable slot 20 causes the strip 18 to bend away from the base 13 and move the blade 29 away from contact 31 against a stop 41. A second, similarly-acting, bimetal strip 19, tensioned by a screw 27, retards the action of strip 18 by rotating their common support 24 clockwise when heated by radiation through the aperture 21, which may be adjustable by a slide 22. Conductors 38, 39 ensure good connection between the blade and bracket 28. The switch may be operated in conjunction with the control switch described in Specification 565,996. Either or both of the thermal strips may be heated additionally by conduction. The boiling plate may be as described in Specificaton 586,920, [Group XI].