The thermostat, serving to maintain constant temperature of the cooling water, consists of two valves, 1 and 2, and bellows 3, rigidly attached to the valves and filled with a low- boiling liquid. Until the engine heats up, upper valve 1 remains closed and lower valve 2 opens holes a to allow water to flow through. When the engine has become heated and the temperature of the cooling water is above the required value, the liquid in the bellows boils. The increased pressure stretches the bellows, opening valve 1 and simultaneously closing valve 2. Then the water circulates through the radiator in the direction indicated by the dash-line arrows.
$4084$EHP,Rg$