Products Information │ English

-
Bimetal ?
Bimetal combines two (or sometimes more) metals with different thermal expansion characteristics. The two metals are bonded together into a single plate or strip.

Temperature changes cause different degrees of expansion in the two metals, resulting in a proportionate change in the shape of the bimetal strip. In effect, this converts temperature change information into mechanical motion, which in turn can be used for simple but very reliable temperature detection.


-
Applications with drawings
As previously mentioned, the function of a thermostatic bimetal strip is caused by an alteration in temperature.  Therefore, the bimetal is used in most cases for transformation of a temperature change into movement and/or force. Electric energy can also be used for release of the function in cases where the thermostatic bimetal is electrically heated. Conversely, a movement and a force can be converted into an electrical effect, for instance in a liquid level gauge.
This  means that is a wide range of use for thermostatic bimetal within the fields of measuring,
regulating and safety techniques. Since bimetal is a simple and reliable element, technical development continuously opens new possibilities for utilizing its function. Some important applications for thermostatic bimetal are as follows :


-
Temperature indication 
As in thermometers for air, steam or liquids indication of other characteristics,
for example, indication of electrical current, voltage or power, indication of gas or oil pressure, level of fluid or velocity of flow and quantity of circulating gas.


-
Control
As in thermostats in heatng, cooling, cooking and baking appliances, for control of room temperature
in living-rooms and industrial plants, for stepless control of electrical power, for the control of cooling water circulation or ventilation, as guide plates and valve control of circulating air, gases and exhaust gases, for temperature control in water mixing valves, steam traps and liquid outlets, for use in current and liquid outlets, for use in current voltage regulators, in brightness regulators for twilight switches etc.


-
Time limiting and control
As in toasters, cigar lighters, fluorescent lamp starters and staircase lighting switches.


-
Safety function
As overload protection of electric motors, transformers and wiring, overheating protection in the windings of electric machines and transformers, in gas safety pilot elements, as thermal cut-outs against non-permittable heating in devices and in fire alarms.
Temperature compensation in measuring devices and control units, as for compensation of fluctuating room temperature.


-
The thermostatic bimetal can be heated in different ways;
Heat transmission by conduction, where the bimetal is in direct contact with the source of heat or the medium to  controlled.
Heat transmission by radiation or convection,
Heat developed by passage of electric current, where the bimetal itself serves as resistance and thus as the source of heat.
Indirect electric heating by means of a heating element made of BIMETAL wire, ribbon or strip.

The function of bimetal can be utilized to produce a force, a movement or a combination of both. By using stacks of bimetal strips a relatively great force is obtained by a large movement. parts of heating elements or shunts can be inserted between the bimetal layers. Disadvantages are friction between adjacent layers and risk of corrosion.
When mercury relays, micros wiches or spring contact systems are used as switching units fot an accumulation in spring or magnetic systems, rapid switching action can be obtained, thereby ensuring  make and break contact without flutter or disturbance. A thermostatic bimetal which acts as a direct switching device has a slow action unless it is specially shaped.


-
NEOMAX     :     BL-2, ALBL-2, BR-1, TR-25, TR-40
SHIVALIK    :    SBC206-1, SBC223NI35, SBC721-112