In our previous post related to bimetallic strip thermometer we discussed the salient features of this thermometer alongwith the working principle of this measuring device .Here we will share some of the practical applications of Bimetallic strip thermometer .Also you will get the list of various advantages and limitations of it .
Bimetallic strip Applications
These strips come under the oldest techniques to measure temperature. These are designed in such a way so as to measure high temperatures i.e upto 500°F or 260°C. Here is the list of major application areas of a bimetallic strip thermometer include:
It is used for number of household appliances such as ovens etc.
Other applications of it include its usage in Thermostat switches , grills and Wall thermometers
Circuit breakers for electrical heating devices
Bulb thermometers are good for measuring temperature accurately but problem is that it is difficult to control the temperature by bulb thermometers , So we use bimetallic as bimetallic strip are good at controlling things.
These type of thermometers are used where we want direct readings should be taken, for example,
Laboratory temperature of the bath
Used in fire alarms
A bimetallic strip made of iron and brass is commonly used .When it is heated both metals expand differently, causing the bimetallic strip to bend.
Thus, when a fire occurs, due to heat , both metals expands differently and ultimately results in bending of the bimetallic strip. touches the screw adjacent to it, thus completing the circuit. Once the circuit is complete, alarm bell begins to ring
In Electrical devices
Bimetal strips are used in small circuit breakers so as to protect the circuits from excess of current. A bimetal strip is heated by coil of wire. The wire coils bends and thus controls the linkages that open a spring operated contact. It disturbs the circuit and it can rest when the bimetal strip is cooled down.
Bimetallic thermometers advantages
- These are very simple and robust .
- Bimetallic thermometers are cheap as compare to many other temperature measuring devices .
- The accuracy is between +or- 2% to 5% of the scale .
- These thermometers have the capacity to withstand 50% over range in temperatures.
Although these temperature measuring devices have number of advantages and used in many practical applications but there are some limitation that inhibit its usage during certain conditions .
- These can not be used above 400’C.
- Due to regular use of bimetallic strip , it may permanently deform that results in errors and do not give accurate results .