Patent GB-544163-A (GB)
Title: Improvements in or relating to automatic regulators to control the temperature-time cycle in heating or cooking plants or the like
IPC: G05D23/19
Filed: 1940-11-03
Abstract: 544,163. Temperature regulators. ELECTROFLO METERS CO., Ltd., WRIGHT, A., and SMITHSON, A. Nov. 3, 1940, No. 14837. [Class 135] [Also in Groups XVIII and XXXVII] In an automatic regulator for the time-temperature cycle of a steam heated vulcanizer or cooking plant wherein a rotary cam and follower co-operate with an element movable in response to the controlled temperature a change in the cycle is obtained by adjustment of a knob, screw or the like which changes the position of cam and follower in relation to the element and one means for rotating the cam is associated with adjustable means to vary independently the time occupied by the " rise and " hold portions of the cycle. The cam follower 16 carries an air jet 11 co-operating with a vane 13 moved by the temperature responsive means 15 so that a varying pressure is developed on a pilot valve controlling a diaphragm valve 2 so that less steam is admitted to one controlled apparatus as the vane obturates the jet. The cam has a portion a ... b producing a progressive temperature rise and a portion b ... c holding a steady maximum temperature. A self-starting synchronous motor 18 drives the cam and is fed through alternative circuits containing separately adjustable continuous interrupters, whereby the relation of time and circuit closure to interruption may be varied. Thus the duration of the " rise " and " hold parts of the cycle may be varied. The maximum temperature may be varied by a knob 24 geared to a sector 24a, carrying the cam and pivoted about the common axis of follower 16 and vane arm 13a. A scale 25 may be added. When the follower 16 reaches the " hold " portion of the cam a switch 20 is operated whereby the motor circuit is changed to include a different interrupter. At the point c of the cam the follower falls into contact with a switch 22 to open the motor circuit and stop the cam. The vane 13 is then fully covering the the jet and the steam valve is closed. At the same time a resetting switch 23 is operated whereby the control of the motor is transferred to switches 33, 34, associated with the door of the steam vessel. These are arranged so that the motor is not restarted until the door has been unclamped and opened whereupon the motor turns the cam to the start position a and stops. The regulator is associated with a check-valve switch 43 arranged to prevent the door being opened unless air pressure has been reduced to zero or a predetermined value and/or a switch preventing supply of steam until after the door has been closed. A switch 38 associated with the shaft of a displaceable pinion for operating the door fastening and a motor 39 for locking the pinion co-operates with the control of the regulator motor and of electromagnetic valves for the supply of compressed air to the regulator and to a diaphragm operated exhaust valve which is effected with the aid of electromagnetic relays and includes signal lamps indicating the completion of the heating cycle, the exhausting of steam from the vessel and the resetting of the regulator.