GB869795A - Improvements in or relating to automatic temperature control apparatus - Google Patents

Abstract

869,795. Thermal switches. SOPAC REGULATION. May 28, 1958 [May 29, 1957], No. 17093/58. Class 38 (5). [Also in Group XIII] Of switch contacts 45, 46 controlling the heating or cooling of a medium used to heat or cool a space, e.g. in a building or train, contact 46 on a lever 47 having a pivot 48 is moved by bellows 4 and 10 operating in tandem on the lever and responding respectively to the temperature of the air outside the space and to the temperature of the medium, while contact 45 is moved by bellows 19 responsive to the speed of the wind outside the space since its pilot bulb 15 is adjacent an electric heater 16. The magnitude of the movement of the contact 45 is controlled by the position of a pair of rollers 29, 31, Fig. 2, along spring-loaded levers 26, 41 pivoted respectively at 27 and 42, Figs. 1, 3. The rollers 29, 31 are independently journalled on a spindle mounted on an arm 32 pivoted at 33 on one end of an L- shaped lever 34 which is adjustable sideways with respect to its pivot 35 and loaded by a spring 37 so that a knife edge at the other end rests adjustably on a shoulder 6 of the rod 5 of the bellows 4. Wind-cooling causes lowering, Fig. 3, of a lever 21 and its adjustable stud 23 and in turn levers 26 and 41 and contact 45 are lowered so that the contacts 45, 46 meet, that is if the pivot 27 and the spindle of the rollers 29, 31 are not aligned as in Fig. 1. The apparatus is adjusted to give the position of Fig. 1 (to give no contact movement with wind change) when the temperatures inside and outside the space are equal. This adjustment is made by raising or lowering the pivot 35 of L-lever 34 by means of a knob 38 by which a plate 49 bearing the pivot 35 and the pivot 48 is raised or lowered. The position of the rollers 29, 31 and therefore the magnitude of the movement of the contact 45 is controlled automatically by the movement of the shoulder 6 associated with the bellows 4 when the inside and outside temperatures differ. Should the temperature of the heated space become excessive, the bellows 10 responding to the temperature of the heating medium raises an adjustable arm 52 to open a switch 51 and thus stop forced circulation of the medium. The switch 51 does not operate under normal conditions.