Table of Contents
What is temperature Switch?
Temperature switches are typically electromechanical devices, used in industrial and manufacturing processes and are responsible for the monitoring and controlling of temperature, with the ability to turn on and off when a certain temperature is reached.
How do temperature switches work?
Temperature switches can be set to react to a certain temperature. When the sensing probe of the switch detects an increase of temperature, it opens or closes the electric contacts. When the temperature decreases, the electrical contacts get back to its normal condition.
Types of temperature Switch?
We can categorize the Temperature Switches into two Categories.
- Mechanical Temperature Switch
- Electronic Temperature Switch
1:- Mechanical Temperature Switch
There are two types of temperature switches:
(I)Bimetallic Temperature Switch
The bimetallic thermometer uses the bimetallic strip which converts the temperature into the mechanical displacement. The working of the bimetallic strip depends on the thermal expansion property of the metal. The thermal expansion is the tendency of metal in which the volume of metal changes with the variation in temperature.Every metal has a different temperature coefficient. The temperature coefficient shows the relation between the change in the physical dimension of metal and the temperature that causes it. The expansion or contraction of metal depends on the temperature coefficient, i.e., at the same temperature the metals have different changes in the physical dimension.
(II) Liquid expansion thermometer
It is a liquid filled temperature switch which comprises a brass bulb filled with a chemical fluid or gas. It includes a small tube which hooks up the bulb to a pressure sensing mechanism consisting of bellows, bourdon tube or diaphragm. When temperature inside the bulb increases, it gets hot and causes the liquid or gas inside the bulb to spread out. This expansion of liquid increases the pressure inside the bulb. This rise in pressure results in the activation of the pressure switch connected to the bulb.
2. Electronic Temperature Switch
Electronic temperature switch consist measuring element, electronic circuit and power supply source, measuring temperature is converted into a switching signal or an amplified standardised electrical signal via the change in temperature of the measuring element. This electrical signal varies in proportion to the temperature and can be evaluated accordingly.