Thermocouple is a sensor for measuring temperature. This sensor consists of two distinct metal wires that are connected at one end and connected at the other end to a thermocouple thermometer or other thermocouple powered device. If properly configured, thermocouples can provide temperature measurement over a wide range of temperatures.
Thermocouples are used as temperature sensors in a wide range of industrial applications due to their temperature sensing capabilities (from a industrial thermocouple to the use of a common thermocouple found in electrical installations and common appliances.) According to a wide range of models and their technical specifications, understanding its basic structure, how it works, its ranges to better determine The right type and material of thermocouple for your application is very important.
Wire thermocouple
A coreless wire thermocouple is the simplest form of thermocouple. It consists of two pieces of thermocouple wire joined together by a welded nut. Because the thermocouple bead is exposed, there are several application limitations. Liquids that can corrode or oxidize the alloy of the thermocouple should not be used in the coreless wire thermocouple. Metal surfaces can also be problematic. Metal surfaces, especially pipes, are often used for electrical systems. Indirect connection to the electrical system can affect the thermocouple measurement. In general, wire-wound thermocouples are a good choice for gas temperature measurement. Because they can be made very small, they also provide very fast response time.
Thermocouple probe
The thermocouple probe consists of a thermocouple wire that is placed inside a metal tube. The tube wall is called the probe sheath. Common sheath materials include stainless steel and Inconel. Inconel supports a higher temperature range than stainless steel, however, stainless steel is often preferred due to its wider chemical compatibility. For very high temperatures, other outer sheath materials are also available.
Thermocouple probe tips are available in three different styles. Baseless, baseless and exposed. With the base tip, the thermocouple is in contact with the sheath wall. A ground connection gives you fast response time, but is more prone to electrical ground loops. In ungrounded connections, the thermocouple is separated from the sheath wall by an insulating layer. The tip of the thermocouple protrudes from the sheath wall with an exposed joint. Exposed junction thermocouples are suitable for measuring air.
Survey Probe surface probe
Measuring solid surface temperature is difficult for most types of temperature sensors. To ensure an accurate measurement, the entire measuring area of the sensor must be in contact with the surface. This is difficult when working with a rigid sensor and a rigid surface. Because thermocouples are made of removable metals, the junction can be formed flat and thin to provide maximum contact with a rigid solid surface. These thermocouples are an excellent choice for surface measurement. The thermocouple can even be made into a rotating mechanism, which is suitable for measuring the temperature of a moving surface. Type K is ChrOMEGA Al / AlOMEGA
How does a thermocouple work?
When two wires consisting of dissimilar metals are joined at both ends and one end is heated, there is a continuous current flowing in the thermoelectric circuit. If this circuit is broken in the center, the open circuit voltage (Seebeck voltage) is a function of the junction temperature and the composition of the two metals. This means that when the junction of two metals is heated or cooled, a voltage is generated that can be related to temperature.