The sort of tube used for protection thermocouples is a thermocouple that is designed to insulate the thermocouple element from the atmosphere of the measurement target. At the present time, most applications employ sheathed type thermocouples; however, for platinum-based noble metal thermocouple protection tubes protective tube types are more often used due to production difficulties and cost limitations with sheathed types.
Thermocouple Principle
There is a thermo-electromotive force and a current flow in a closed circuit when a temperature difference occurs at the contacts of both ends of a thermocouple, which comprises two metal wires of different kinds linked at both ends. Thermal-electromotive forces are impacted only by the temperature of the wires at both ends and the combination of two metal wires; they are not affected by the wires' thickness or length. For this reason, if you know the thermo-electromotive force at each temperature of a thermocouple, you can determine the temperature.
This means that the temperature measurement range, status of the measuring site, and accuracy requirements must all be considered when selecting thermocouple protection tubes. They must also maintain their performance even after extended periods of continuous operation. In addition to JIS-standard type B thermocouples and W-5Re/W-26Re thermocouples, we produce types R, S, N, K, E, and J thermocouples as well. Choose your thermocouples wisely based on your adoption goals.
How does a Thermocouple work?
When it comes to thermocouples, everything from the thermocouple element to the mounting brackets and connectors and insulators is included.
- Temperature-Sensitive Components
Through the use of welding, a temperature measurement connection is created at the element's tip end.
- Tubes of Defense
A thermocouple protection tubes element and insulator are shielded from the environment by a protective tube, which includes a mounting bracket and a termination box. Protective tubes may be subjected to very harsh circumstances depending on where temperature readings are taken. The materials and shapes of the protective tube must be chosen according to temperature, atmosphere, purpose, and other factors.
- Terminal Plates and Boxes
Compensating cables are connected to thermocouples via terminal boxes. We have aluminum die-casting type EL terminal boxes (drip-proof) and various materials and shapes suited for the intended function.
- Insulators
Insulators are used to protect thermocouple wires and tubes from short-circuits by providing insulation. JIS 2 insulators are the ones we use.
- Bracket for mounting
The thermocouple is mounted on a measurement location using a mounting bracket coupled to a safety tube. There are more thermocouples that may be utilized without the necessity of a protective tube. EXE and EXS thermocouples are ideal for basic measurements since they merely include a heat contact linked to the end of the coated thermocouple wires. A Teflon resin such as FEP is often used to coat type EXS thermocouples, hence a Teflon-coated insulation type is also available.
