Armored high-temperature thermocouple is a widely used temperature measurement instrument in high-temperature environments, which has the advantages of compact structure, fast response speed, high temperature resistance, and corrosion resistance. Proper installation and use of armored high-temperature thermocouples are crucial for ensuring measurement accuracy and extending equipment lifespan. The following is a complete operation specification guide from wiring method to maintenance.

1、 Basic principles

It works based on the thermoelectric effect. When two different metals (such as copper and constantan) form a closed circuit, if there is a temperature difference between the two ends, an electromotive force (thermoelectric potential) will be generated in the circuit. By measuring this electromotive force and combining it with the calibration table of the thermocouple, the measured temperature can be determined.

The structure of armored thermocouples typically includes thermoelectric electrodes, insulation materials, and protective sleeves, which enable them to operate stably in high temperatures and harsh environments.

2、 Installation

1. Installation location selection

Representativeness: Thermocouples should be installed in locations that can represent the temperature of the measured medium, avoiding installation in blind spots or places with drastic temperature changes.

Avoid interference: Stay away from strong magnetic fields, electric fields, and vibration sources to prevent signal interference.

Medium contact: Ensure that the measuring end of the thermocouple is in full contact with the measured medium, avoiding insulation or convection effects.

2. Installation method

Insertion depth: Select the appropriate insertion depth based on the temperature and flow conditions of the measured medium. It is generally recommended to insert at a depth of 1/3 to 1/2 of the length of the thermocouple protection tube.

Fixing method: Use a dedicated mounting bracket or threaded connection to fix the thermocouple, ensuring its stability and avoiding loosening due to vibration.

Protective measures: In high temperature or corrosive environments, ensure the integrity of the protective sleeve and install a protective cover if necessary.

3. Wiring method

Compensation wire: Armored thermocouples typically require the use of compensation wires to connect to measuring instruments. The model of the compensating wire should match the thermocouple, and the wiring should be correct and error free.

Wiring polarity: Ensure that the positive and negative poles of the thermocouple are correctly connected to the positive and negative poles of the compensation wire. Incorrect polarity can lead to measurement deviation.

Sealing of junction box: After wiring is completed, the junction box should be sealed to prevent dust, moisture, etc. from entering and affecting measurement accuracy.

3、 The use of armored high-temperature thermocouples

1. Calibration and Calibration

Before installation, the armored thermocouple should be calibrated to ensure that its measurement accuracy meets the requirements.

Regularly (e.g. every 6 months or 1 year) calibrate thermocouples to correct for possible drift.

2. Measurement range

Ensure that the measured temperature is within the measurement range of the armored thermocouple. Exceeding the range may result in inaccurate measurements or damage to the thermocouple.

3. Signal transmission

Use shielded cables to connect thermocouples and measuring instruments, reducing interference during signal transmission.

Ensure that the length of the compensating wire does not exceed the specified range (usually within 100 meters).

4、 Maintenance and upkeep of armored high-temperature thermocouples

1. Regular inspection

Appearance inspection: Regularly inspect the appearance of the thermocouple to see if there is any damage, corrosion, or deformation.

Insulation inspection: Use a megohmmeter to check the insulation resistance between the thermoelectric electrode and the protective tube to ensure good insulation.

2. Cleaning and maintenance

Cleaning: Regularly clean the dust and dirt on the surface of the thermocouple to prevent affecting measurement accuracy.

Anti corrosion treatment: In corrosive environments, regularly inspect the anti-corrosion coating of the protective casing and repair or replace it if necessary.

3. Replacement and maintenance

Damage replacement: If the thermocouple is damaged or the measurement accuracy decreases, it should be replaced in a timely manner.

Maintenance record: After each repair or replacement, keep a record, including information such as date, reason, and replacement parts.

4. Storage

Storage conditions: Unused armored thermocouples should be stored in a dry and clean environment to avoid moisture or corrosion.

Protective measures: When storing, the measuring end of the thermocouple should be protected with a protective cover to prevent damage.

5、 Common problems and solutions

1. Measurement deviation

Reason: Wiring error, thermocouple damage, compensation wire mismatch, etc.

Solution: Check if the wiring is correct, replace damaged thermocouples or compensating wires.

2. Unstable signal

Reason: Loose wiring, electromagnetic interference, unstable installation of thermocouples, etc.

Solution: Check and tighten the wiring, use shielded cables, and ensure that the thermocouple is securely installed.

3. Damaged thermocouple

Reason: Over temperature use, corrosion, mechanical damage, etc.

Solution: Replace the damaged thermocouple, ensure it is used within the specified temperature range, and strengthen anti-corrosion measures.

VI. Summary

Armored high-temperature thermocouple is an efficient and reliable temperature measurement tool, but its correct installation, use, and maintenance are key to ensuring measurement accuracy and extending service life. By selecting the installation location reasonably, wiring correctly, maintaining regularly, and replacing damaged parts in a timely manner, the advantages of armored thermocouples can be fully utilized to meet the high temperature measurement needs in industrial production.