The cleaning method before the thermocouple detection you know what

Thermocouple has the advantages of high accuracy, good stability, wide temperature measurement area, long service life and so on, excellent physical and chemical properties, thermoelectric potential stability and good oxidation resistance at high temperature, suitable for oxidation and inert atmosphere, but xiaobi to remind you to do a good job of cleaning before thermocouple detection, the method is as follows:

1. Cleaning:

Precious metal thermocouple should be cleaned before verification in order to eliminate impurities, organic matter and oxides on the surface of the thermal electrode, and then reduce the contamination of the thermal electrode, so that the thermoelectric characteristics are stable and extend the service life. Armoured thermocouples do not require cleaning. Pickling is to remove organic matter and some oxides from the surface of the hot electrode.

2, pickling:

Put the thermocouple disk into a circle with a diameter of no less than 80mm and immerse it in the hydrochloric acid solution with a concentration of about 30% chemical purity for 1h or boil it for 15min. After taking it out, boil it with distilled water several times until the acidity is eliminated.

3, borax washing:

Borax is a colorless crystal, heated about 400℃, that is, dehydration into sodium tetrborate. Sodium tetraborate has a very low melting point and melts into vitreous form at 878℃. It consists of sodium borate and boron gangue. The molten borax dissolves the metal oxide and forms a stable glassy compound with the oxide, which removes the metal oxide from the surface of the hot electrode. Borax is a good purifying agent for metals. This method is to use borax at high temperature has the ability to dissolve metal oxides, precious metal thermocouple surface cleaning clean.