Q1: What is a thermocouple?
A1: A thermocouple is a commonly used temperature-measuring component in a temperature-measuring instrument. It directly measures the temperature and converts the temperature signal into a term electromotive force signal, which is converted into the temperature of the measured medium by an electric meter (secondary meter). The shape of various thermocouples is often very different due to the needs, but their basic structure is almost the same, usually composed of the hot electrode, insulating sleeve protection tube and junction box, etc., usually with a display instrument, recording instrument and electronic adjustment Used in conjunction with the device.
Q2: What is a K-type thermocouple used for?
A2: As a transmitter for measuring temperature, industrial K-type thermocouples are usually used in conjunction with display instruments, recording instruments and electronic regulators. It can directly measure the surface temperature of liquid, vapor and gaseous media and solids ranging from 0°C to 1000°C in various production processes.
Q3: How does a thermocouple work?
A3: A thermocouple is the connection of two different conductors or semiconductors into a closed circuit. When the temperature of the two junctions is different, an electromotive force will be generated in the circuit. This phenomenon is called the hot spot effect, also known as the Seebeck effect. The end directly used to measure the temperature is called the working end, and the other end is called the cold end. The cold end is directly connected to the instrumentation or supporting equipment, and the display instrument will point out the electromotive force generated by the thermocouple.
Tips: Thermocouple Troubleshooting
Trouble |
Reasons |
Solutions |
The thermoelectric potential is smaller than the actual value (the indication value of the display instrument is low) |
Thermode shorted. |
If it is caused by moisture, dry it; if the insulator is damaged, replace the insulator. |
Dirt builds up on the thermocouple terminals, causing a short circuit. |
Clean up dust. |
Compensate for wire-to-wire short circuits. |
Find out the short circuit point, strengthen the insulation or replace the compensation wire. |
Deterioration of thermocouple thermode. |
If the length allows, cut off the metamorphic section and re-weld it, or replace it with a new thermocouple. |
The polarity of the compensation wire and the thermocouple is reversed. |
Reconnect correctly. |
The compensating wire does not match the thermocouple. |
Replace the corresponding compensation wire. |
The installation position of the thermocouple is not recorded or the insertion depth does not meet the requirements. |
Re-install as specified. |
The temperature compensation of the cold junction of the thermocouple does not meet the requirements. |
Adjust the cold junction compensator. |
Thermocouples are not compatible with display instruments. |
Replace the thermocouple or display instrument to match it. |