What Is a Thermostatic Bimetal?
Thermostatic bimetals are thermostats (temperature contact devices) that have a function of breaking the circuit by warping the metal and separating the contacts when a certain temperature is reached. This is due to differences in the properties of the two different metals (called bimetals). Thermostats are generally referred to as thermostatic bimetals. This type of thermostat has a long history and does not use semiconductors or other materials that are relatively sensitive to the environment, making it highly reliable.
Uses of Thermostatic Bimetals
Thermostatic thermostats are used in environments where semiconductors, electronic circuits, and sensors are commonly used for temperature protection. The old-fashioned thermostatic bimetal is still used in harsh environments where such sensitive components cannot withstand the harshness of the environment. The reliability of the old-fashioned thermostatic bimetal is still in use today because of their high reliability. As a temperature protection component, the thermostatic bimetal uses only metal materials, making them extremely difficult to break.
Principle of Thermostatic Bimetals
A thermostatic bimetal consists of two or more metal plates with different coefficients of thermal expansion that are laminated together. By applying this property and using the warped part as a contact point for opening and closing, it is possible to turn on and off heat sources and power supplies and to control temperatures. Originally, the thermostat was an open/close device meant to maintain a constant temperature, and it has been used to open and close contact points of sensors, power supplies, heaters, etc., using the difference in warping of two or more pieces of metal due to temperature. The metals used include chromium, manganese, magnesium, and other metals as additives in alloys such as iron and nickel on the high expansion side. Conversely, on the low expansion side, an alloy of iron and nickel with a lower expansion coefficient is used. Ultimately, the main component of the bimetal that operates the contacts both with a high and low expansion coefficient is an alloy of iron and nickel, which is cheap, easy to process, and durable.