Patent GB-522002-A (GB)
Title: Improvements in or relating to thermostatic valves
IPC: G05D23/12
Filed: 1938-11-02
Abstract: 522,002. Thermostats. SHERLOCK. J. E., and BRITISH THERMOSTAT CO., Ltd. Nov. 2, 1938, Nos. 31738/38 and 35833/39. [Class 135] A thermostat particularly adapted for use in gas cooking stoves, and of the kind having a valve actuated by a diaphragm closing a chamber connected to a terminal feeler, has the casing formed in two parts, one part including the diaphragm chamber, valve seat and gas inlet and outlet. the other part including the control mechanism and a connection between the valve seat and the inlet or outlet. The main valve 26 has a peripheral guide flange slidable in an annular ring 21 screwed to the casing 1 and cooperates with a flanged cylindrical seat 27 clamped between two parts of the casing. A diaphragm 23 resting on the valve member is clamped peripherally to the ring 21 by a cap 22 to provide a shallow pressure chamber coupled by a capillary pipe to a thermal feeler (not shown) containing nitrogen or other incondensible gas. A hollow frusto-conical plug 20 having a port 13 adapted to co-operate with a port 14 connected by a passage 15 with the gas inlet 3 is mounted in a detachable part of the casing 2 coaxial with the valve 26. The actuating knob 42 for this cock is secured by screw 65 and distance pieces 66 of appropriate length to a plate 43 having inwardly directed projections adapted to engage slidably with slots in the cock spindle 12. This plate has a pair of studs 48 with flanged heads adapted to take over the edge of a plate 49 secured to the valve casing. The plate 49 has depressions 51 into which the heads of the studs sink, under the action of a spring 50, when the cock is in the open or closed position. The diaphragm is loaded by two springs one 30 arranged between the valve member and a flange 31 on the seat and the other 20 between an abutment 32 supported by a central projection 33 on the valve member and an adjustable abutment 34. This abutment, which is held against rotation by a projection 36 engaging a longitudinal slot in the cock plug, has a screw threaded engagement with a sleeve 35 slidably mounted on the temperature adjusting spindle and adapted to be rotated by a transverse pin 38 engaging a slot in the spindle. The pin 38 rests on a rod 40 adjusted by a screw 41 in a central bore of the spindle to adjust the primary setting of the device. The spindle has a sealing collar 18 engaging a packing at the smaller end of the cock plug and has a longitudinal slot 53 engaging a pin 52 on a sleeve 47 rotatably mounted in 'the knob 42. A manipulating knob 44 with a pointer 45 is secured to the sleeve 47 by a screw 46 engaging one of a series of holes in the sleeve. Two byepass passages are provided, one.leading past the main valve and controlled by a screwed ported 'throttling pin and the other leading to a byepass conduit and controlled by a screwactuated needle valve. According to the first Provisional Specification a temperature indicator may be fitted comprising a rod and quick pitched screw extending through the adjusting spindle. The casing may be provided with alternative pipe connections, some of which are plugged when not required.