Depending on the temperature of the environment, Thermostat internal liquid physical deformation, Resulting in some special thermal protection effect, An automatic temperature control element which is turned on or off, Called liquid expansion thermostat, Also known as liquid expansion temperature switch or temperature controller, Referred to as thermostat.
　To the refrigerator temperature control example, The thermostat is a switchgear that controls the temperature of the refrigerator. The temperature range of the refrigerator controlled by the inflatable thermostat is generally in the range of -18 ° C to 5 ° C. Refrigerator commonly used temperature controller is to liquid pressure principle to promote the contact with the broken off. Its structure by the bellows, temperature package (test tube), eccentric wheel, Micro switch, etc. constitute a sealed induction system, and a transfer signal power system.
　Control methods are generally divided into two; One is controlled by the temperature change of the object to be cooled, The use of steam pressure-type temperature controller, And the other is controlled by the temperature difference of the object to be cooled, More use of electronic temperature controller.
The thermostat is divided into:
　Mechanical type is divided into: steam pressure thermostat, Liquid expansion thermostat, gas adsorption thermostat, metal expansion thermostat.
  One vapor pressure thermostat is divided into: Inflatable, liquid and gas mixed type and filling type. Household air-conditioning machinery are mainly in this type of thermostat.
Technical guide:  <Liquid expansion capillary thermostats Precautions>