Zhengzhou Kejia Electric Furnace shares the structure and type of thermocouple for you
Time：2020-12-18 08:56 Click：
There are many types of thermocouples. The high-temperature box furnaces, vacuum tube furnaces, muffle furnaces, box-type atmosphere furnaces and other laboratory high-temperature heating equipment we have developed and produced are commonly used in laboratory high-temperature heating equipment. Here we Zhengzhou Kejia Electric Furnace Co., Ltd. will share with you the structure and type of thermocouple.
Composition of thermocouple
In actual temperature measurement, a thermocouple with only two hot electrodes is rare. Ordinary thermocouples are usually composed of four parts: thermode, insulating tube, protective sleeve and junction box.
(1) Thermoelectrode: The thermoelectrode is the core part of the thermocouple. The hot electrode of the ordinary thermocouple is usually processed into a wire shape and welded at one end. The diameter of the thermoelectrode is mainly determined by the price of the material, the mechanical strength, the use of the thermocouple and the temperature measurement range. The diameter of precious metal thermoelectrodes is generally 0.3-0.65mm, and the diameter of cheap metal thermoelectrodes is generally 0.5-3.2mm.
The length of the hot electrode is often made into various specifications in the range of 100-200mm for practical selection.
(2) Insulating tube: The insulating tube is also called an insulator, with a through hole sleeved on the hot electrode to isolate the two electrodes and isolate the electrode from the metal protective sleeve. Otherwise, the thermoelectric potential will be lost due to a short circuit and cause measurement. error. Insulators are usually made of high temperature resistant insulating materials such as ceramics, quartz, alumina, magnesia and other materials, with round or oval cross-sections, and single-hole, double-hole, and four-hole forms.
(3) Protective tube: The thermoelectrode covered with an insulating tube is installed in a protective tube closed at one end. The function of the protection tube is to prevent or reduce the direct erosion of the hot electrode by various harmful gases and harmful substances and the direct sprint of the high-temperature flame or airflow; prevent the direct contact between the conductive medium and the hot electrode; in addition, there are fixing and supporting the hot electrode effect. Therefore, the protection tube of the thermocouple plays a major role in extending the service life of the thermoelectrode and ensuring the measurement accuracy.