GB1505378A - Fluid pressure operated thermostat - Google Patents

Abstract

1505378 Temperature responsive actuating elements INDUSTRIE-WERKE KARLSRUHE AUGSBURG AG 8 May 1975 [24 May 1974] 19330/75 Heading G1D A thermostat comprises a fluid, e.g. liquid, filled temperature sensor 8 connected to a fluidpressure responsive actuator 9 for connection to a flow control valve via a chamber which is variable in volume to set a reference temperature and which is connected to an excess pressure reservoir 3, whereby variations in fluid-pressure cause operation of the actuator 9 and excessive fluidpressure is relieved by passage of fluid into the reservoir 3 from whence it returns on subsequent reduction of pressure in the chamber. The chamber may be a cylinder 2c the volume of which is varied by movement of a piston 2e by means of a setting knob 2b. The reservoir may comprise a diaphragm 3b, which is normally retained in position shown by nitrogen 3a under pressure, or an enclosed space bounded by a flexible continuous wall. The housing 1 incorporating the reservoir 3 and regulating device 2 may be separate, as shown, being connected to the actuator 9 and sensor 8 by capillary tubes 7a, 7 or may be incorporated in the temperator sensor Fig. 3 (not shown) or in the actuator Fig. 2 (not shown) the reservoir being in these latter cases within the piston 2e. Alternatively, the actuator, sensor and chamber may be located in a single housing. The reservoir 3 may be connected to the chamber via a filter 3c of sintered material.