After about 5 minutes of connecting the electric kettle to the power supply, the steam causes the bimetallic plate of the steam temperature sensing element to deform, and the top opening switch contacts disconnect the power supply. If the steam switch fails, the water in the pot will continue to boil until it is dried, causing a sharp increase in the temperature of the heating element. There are two bimetallic plates located at the bottom of the heating plate, which will rapidly increase in temperature due to thermal conduction, expand and deform, and disconnect the power supply. Therefore, the safety protection device for electric kettles is designed very scientifically and reliably.

The whistle type electric kettle is made of stretched aluminum plate, and the electric heating element adopts a submerged nickel plated steel sealed electric heating tube. The electric heating tube is installed at the bottom of the kettle, and a heat-resistant sealing ring is padded at the junction with the kettle body to prevent water leakage. This type of electric kettle is equipped with a strip shaped vibrating spring plate buzzer (air flow vibrating whistle device) on the lid, which will sound when the water temperature reaches 100 ℃ or above. Due to the fact that this type of kettle is generally not equipped with a temperature limiting controller, it is necessary to manually cut off the power supply. This type of electric kettle has a simple structure and low price, and is widely used in residential households.