GB1160551A - Improvements in and relating to Temperature Responsive Control Apparatus - Google Patents

Abstract

1,160,551. Valves. W. A. KEALY. 12 Sept., 1966 [11 June, 1965], No. 24790/65. Heading F2V. [Also in Division G1] A temperature sensitive actuator comprises a sensor, Fig. 1, coupled by a conduit 24 to an actuator, Fig. 2, e.g. for a valve 33, a bellows 20 or 42 being provided at each end of the conduit together with a screw down valve 47 for admitting liquid to the space enclosed by the bellows and the conduits, the liquid preferably being that controlled by the valve 33. The temperature sensor comprises a plate 10 adjustable in bars 13, 14, a bellows 11 being sealed between the plate 10 and an end plate 12. The bellows 20 is contained inside the bellows 11 and communicates with a bore 21 leading to the conduit 24. The position of the plate 10 on the bars 13, 14 is adjustable by use of a screw-threaded stop 16, a spring 15 urging the plate 10 to its adjusted position. This adjustment controls the actuation temperature of the valve 33. The bellows 11 is filled with temperature sensitive fluid, e.g. methyl chloride or toluene, and expansion of this material or increase in its vapour pressure acts on the bellows 20. Abnormal temperature conditions will cause compression of the spring 15 preventing damage to the actuator. A screw-down bleed valve 23 is provided to assist in filling the conduit 24 with liquid. In the actuator, Fig. 2, the bellows 42 acts to close the valve 33 in a hot water pipe against the action of a spring 35. The liquid whose flow is controlled by the valve 33 is in communication with the space 40 surrounding the bellows 42 by way of a clearance provided round the valve stem, and by opening the valve 47 this liquid can be admitted to fill the conduit 24 and the two bellows 20, 42. In an alternative embodiment the valve 47 controls the entry of liquid into the space 40, so that the actuator functions free from disturbances due to fluctuations in the pressure of the liquid controlled by the valve 33. The bellows may be replaced by diaphragms, capsules or Bourdon tubes, and a separate liquid filling for the conduit 24 and bellows 20, 42 may be provided. Alternative mechanical means for adjustment of the sensor are described or the sensor may comprise a bimetallic or solid differential expansion element.