Thermostats

These are based on the characteristics of special waxes with a high dilation coefficient. This type of Thermostat possesses a rubber diaphragm surrounded with wax and an elongated rod. The wax is closed in a metallic capsule in contact with the water. When the wax is cold, the valve is closed and blocks the way of the water to the radiator. When the wax warms up it expands, expelling the rod and due to the action-reaction phenomenon, the valve opens. The closing takes place by means of a spring after the wax cools down.

This kind of Thermostat is the most widely used type of thermostats at present and is mounted originally in all internal combustion engines.