I. Causes of leakage on thermocouple:
(1)The refractory bricks in the electric heating thermal oil furnace have poor insulation at high temperatures. Inserting a thermocouple with a metal tube into the furnace wall where the heating wire is installed can easily cause contact between the heating wire and the thermocouple. Refractory bricks are good insulating materials at room temperature. Our company's product - the liquid level meter, as the temperature rises, the insulation performance will significantly decrease.
(2)Contact between the heating wire and the thermocouple. The protection tube of the platinum-rhodium thermocouple is made of alumina ceramic tube, and the thermocouple wires are separated and insulated by ceramic tubes. At high temperatures, the insulation performance also decreases, causing leakage, which eventually leaks to the thermocouple, resulting in an AC leakage signal on the thermocouple.
II. Solutions to thermocouple leakage:
(1) Keep the thermocouple from contacting the refractory bricks.
(2) Ground the negative electrode of the thermocouple to eliminate the leakage signal on the thermocouple.
(3) Install a filter device at the output end of the thermocouple.
(4) Lead a ground wire from the hot junction of the thermocouple and ground it.
(5) Add a heat-resistant steel tube or silicon carbide tube over the thermocouple tube, and ground it. The magnetic flap level gauge.
