GB825269A - Improvements in thermostatic regulator valves - Google Patents

Abstract

825,269. Fluid-pressure servomotor-control systems. LANDIS & GYR A.G. Jan. 29, 1958 [Feb. 7, 1957], No. 2961/58. Class 135. A thermostatic valve comprises a capsule 17 adjustable at 19 and connected at 18 to a thermal feeler for alternatively positioning two connected valves 21, 22 with respect to opposite ends of a valve seat 14 and controlling the leakoff of high pressure from a chamber 9 on one side of a diaphragm 7 supplied by a throttle 12 from the inlet 2 to a Venturi 10, a leak-off leading via 15 and 13 to the throat of the Venturi and a low-pressure chamber 8 beneath the diaphragm, the diaphragm actuating a valve 5 controlling heating or cooling medium flowing through the passage containing the Venturi. With heating medium flowing through the Venturi to a room heat-exchanger, a rise in room temperature makes the capsule 17 move the valve 21 towards its seat at top of the opening 14 so that diaphragm 7 descends and closes valve 5. When cooling medium flows, a bimetal strip 24 is cooled and snaps upwards whereby valve 21 is moved away from the opening 14 and valve 22 is moved to control the lower side of the opening whereby rise of temperature in the cooled space makes capsule 17 move valve 22 away from its seat whereby diaphragm 7 rises and opens valve 5. In a further embodiment the spring 27 loading valve 5 is replaced by a diaphragm loaded by inlet pressure and a spring-controlled lost-motion device is incorporated in the stem 20 to prevent the strip 24 damaging the diaphragm.