Measuring method of platinum-rhodium thermocouple

The stand or fall of platinum-rhodium thermocouple performance, natural need to pass test to know. However, before the test, also need to see if the appearance of the platinum rhodium thermocouple is normal, only the appearance quality, it is necessary to continue testing. Usually at the time of testing, shall be for the thermocouple to be detected on thermocouple special porcelain bushing.

it is important to note that the following product under test should be prepared with standard platinum-rhodium thermocouple in the tube furnace, hot end of this time should be inserted in the cylinder. Then put their compensation the cold end of the wire in the zero degrees Celsius in the container. And maintain the temperature of pipe furnace in the thermocouple temperature allowed by the laws of and then use the detection qualified Whitaker sten potentiometer to measure standard thermocouple and under test thermocouple thermoelectric potential difference, recorded at the same time.

according to the measured data above to find out the temperature of the corresponding points. If tested platinum-rhodium thermocouple super bad, then it can be judged to be unqualified. For thermocouple is unqualified, can cut off a little from the hot end, a new welding. Specific operation method is: if it is the ordinary nickel-chromium thermocouple, you can use autotransformer voltage down, and then use the two thermocouple wire and into a pole, the other with the carbon rods, direct ignition arc, two thermocouple wire will melt into a small ball in the head.

in the operation of the process, must pay attention to safety. Especially in the use of autotransformer, be sure to ensure that the insulation is good. For welding platinum rhodium thermocouple is used in another way: after the first turn on the pressure regulating power an insert in sodium chloride solution, the other pole is thermocouple, thermocouple insulation clamps live hand solution surface, can complete the welding.

then we in the complete welding platinum rhodium thermocouple test, determine the qualified or not.