Temperature Switches

Temperature switches are used in many different maritime, industrial and technical processes. A temperature switch functions like a light switch. When the preset temperature is reached, the temperature switch opens up or closes the required switch contact. An electronic- or mechanical temperature switch is more suited depending on the process requirements.

What is a temperature switch?

A temperature switch (thermal switch) is used in a process to open and close switch contacts. The point of switching is determent when the process temperature reaches the set point of the switch. You use a temperature switch to protect your engine, systems or process against overheating or undercooling. Simply phrased, thermal switches are responsible for monitoring the temperature of, i.e. machinery and equipment and are used for temperature regulations.

Types of temperature switches?

There are two types of temperature switches; a mechanical temperature switch and the electronic temperature switch. Mechanical switches are available in a bimetal temperature switch model and gas-actuated temperature switch type. Mechanical temperature switches have a factory set point and have acceptable accuracy.

When high accuracy is required, an electronic temperature switch should be used. With this switch, the switching point is manually adjustable, even at multiple points.

A more uncommon type of temperature switch is the bimetal and gas actuated temperature switch. The bimetal temperature switch has low accuracy but is compact and inexpensive. Gas-actuated temperature switches are primarily used in safety-critical applications.

Temperature switch vs temperature controller?

A temperature switch triggers a switching reaction depending on the temperature that opens or closes the circuit on which it is installed. A temperature controller, on the contrary, determines the precise temperature and compares it with the set point, which is set through an actuator. A temperature controller is therefore responsible for the display, control and monitoring of temperatures.

Bimetal temperature switches

Bimetal temperature switches determine temperature by using a bimetal disc. This disc consists of two metals used as strips or platelets and always has different thermal coefficients. The metals used in a bimetal temperature switch are usually zinc and steel or brass and steel. When the ambient temperature rises and the nominal switching temperature is reached, the bimetal disc changes into its reverse position. 

After cooling to the reset switching temperature, the bimetal temperature switch returns to its previous state. The power supply is interrupted for temperature switches with electrical latching before switching back. Due to the heat, the bimetal deforms in the convex direction, and the contact surfaces can securely touch each other. Bimetal temperature switches can be used as overtemperature protection or as a thermal fuse.

Gas-actuated temperature switches

Gas-actuated temperature switches are the temperature switch of the highest quality. This type of switch is specially designed for safety-critical applications.