Thermal Switches

Mechanical temperature switches were developed to switch an electrical contact when the temperature within the process exceeds defined limits. The temperature may be too high or too low. Temperature switches have no sensitive local display, no analog output signal, and do not require an electrical power supply. These simple devices are optimized to guarantee excellent repeatability and reliability of the switching behavior.

Temperature switches that do not require a power supply are used in safety-critical applications. Bourdon is a well-known supplier of equipment for power plants and offers a wide range of products specifically for nuclear power plants.

However, many other applications, such as monitoring or regulating fluid temperatures in a tank or heat exchangers, also benefit from this safe and simple solution.

Temperature switches are available in EEx ia and EEx d versions for hazardous areas. With capillaries from up to 20 meters away, installation is possible even in difficult installation conditions.

The Bourdon - Baumer Group temperature switch range offers reliability and proven durability against harsh environments and processes.

Bourdon temperature switches can be custom manufactured to suit your application requirements. You can choose from the full range below:

• Temperature range from -46°C to 270°C
• Factory-set or customer-specified set point
• Fixed or adjustable dead band
• Direct mounting or via remote capillary
• Different types of microswitches according to application
• Excellent repeatability of 1%
• Intrinsically safe (EEx ia) version for zones 0, 1, 2
• Explosion proof (EEx d) version for zones 1, 2, 21, 22
• Approvals for nuclear power plants

Mechanical Bourdon temperature switches are designed for alarm setting when temperature limits are exceeded or for temperature regulation between 2 set points.

The sensing element of a temperature switch is a closed, steam-filled system. The pressure in this system depends on the measured temperature. This pressure is applied to a membrane and the membrane operates a mechanical microswitch via a lever.

The value of the set point is determined by the setting of a compressible spring operating in the opposite direction to the membrane. The set point can be set at the factory or by the customer. In some types of microswitches, the deadband can also be adjusted. This allows the set point and reset point to be defined separately.

Bourdon temperature switches offer excellent repeatability in a compact design. Its working principle is completely mechanical and does not require an electrical power source. Wiring is only required for reading microswitches.