Thermostat

摘要

The invention relates to a thermostat with two bellows made of metal which lie one inside the other and between which a working fluid is enclosed, which reacts to changes in temperature with a change in volume. The displaceable end of the inner bellows is connected to an activation element. The free end of the outer bellows lies opposite a stop. The increase in volume of the working fluid as a result of the influence of heat first causes an axial change in length of the outer bellows, until a predetermined temperature is reached. At this temperature the further movement of the outer bellows is prevented by an adjustable stop. In the case of a further increase in temperature and consequent further increase in volume of the working fluid, this displaces the inner bellows axially and thus also the activation element. The particular advantage of this arrangement is that the axial constructional space requirement of the thermostat is small. However, the actuating movements of the activation element are large in comparison with the expansion of the thermostat. In this way the working fluid does not alter its physical state. The response behaviour is favourable, since the required amount of working fluid is small because of the method of construction of the thermostat. <IMAGE>