Simple science secures safety
In the home, a thermocouple is a simple device with an important job --- keeping natural gas and propane appliances from becoming the source of dangerous gas leaks. It's an interesting bit of science; a unique chemical reaction creates electricity from two pieces of hot metal.
Why they are important
Appliances like water heaters and furnaces have a small, constantly-burning flame called a pilot light that ignites their burners when the appliances are turned on. Dangerous gas could escape if that small flame went out, but the thermocouple shuts down the gas supply if the pilot light goes out.
Metals plus heat equals electricity
A thermocouple contains two pieces of different metal, welded together and attached to electrical leads, which get placed in the pilot light flame. A reaction between the heated metals generates a small amount of electricity that travels to the appliance's main gas valve and allows gas to flow.
No heat, no electricity, no gas
If the pilot flame goes out, the valve cuts off the gas supply to both the pilot light and the main burner.
Tags: pilot light