What is precious metals maintenance method of thermocouple _ instrument

If you want to precious metal thermocouple with long time point can use acid oxidation ability, high temperature to remove organic matter on the surface of the precious metal platinum rhodium thermocouple and other impurities can be acid dissolution. Will be high temperature metal platinum-rhodium thermocouple plate into a circle about 80 mm in diameter in the beaker, import 30%, 50% ( According to the volume ratio) Chemical pure dilute hydrochloric acid ( Or dilute nitric acid) One hour, take out into a beaker, thoroughly with distilled water for a few times to remove the acid. The purpose of pickling was part cleaning electrode surface oxide and organic materials. Used the high temperature of precious metals platinum rhodium thermocouple sodium borate cleaning after acid pickling. First high temperature metal platinum-rhodium thermocouple electrode hangs on the platinum wire annealing on the ark, and then to adjust current, make very hot thermocouple to 1100 degrees. With massive sodium borate touch the hot electrode, boric acid solution along the electrode of the water, slowly after cleaning to reduce electric current, then cut off the power and take footwall in 80 mm diameter circle into a beaker, several times with distilled water to boil, completely precipitate boric acid salt. Sodium borate clear purpose is mainly appeal insoluble in hydrochloric acid and metal oxide. Because of sodium borate in high temperature melting and attached to the high temperature metal platinum-rhodium thermocouple hot metal impurity on the electrode and metal oxide generated boron glass solutions, suitable hot electrode outflow, reach the purpose of clearing the outer electrode contamination. Annealing is to eliminate internal stress in the electrode, improve the high temperature metal platinum-rhodium thermocouple phase to improve stability of precious metals platinum rhodium thermocouple. Through proper annealing temperature and annealing time, can achieve the purpose of prayer. Annealing generally has two methods:, electric annealing furnace annealing. For the sake of our precious metal thermocouple service life and save our spending on components, in view of the thermocouple and maintenance is very heavy, even if some trouble, we are still in accordance with the requirements of operation.