Overview of Insertion Thermometer Thermowells
Insertion thermometer thermowell is a device used to protect thermometers from damage and contamination, and is widely used in industrial fields such as chemicals, petroleum, pharmaceuticals, and food. Its core function is to isolate the measured medium from the thermometer while ensuring the accuracy and safety of temperature measurement.
Different models and specifications of thermowells are suitable for different thermometers and measurement needs. This article takes the G1/2 female M20*1.5 thread specification as an example to systematically introduce selection points.
Key Selection Parameters
1. Thread and Connection Specifications
The connection thread is the primary parameter for selection. G1/2 female M20*1.5 means the thermowell process connection is G1/2 female thread, and the thermometer interface is M20*1.5 male thread. During selection, it is necessary to confirm that the pipe or equipment interface matches.
2. Nominal Pressure and Working Pressure
Nominal pressure generally refers to the static external pressure that the protection tube can withstand at room temperature without rupturing. The allowable working pressure is not only related to the protection tube material, diameter, and wall thickness, but also to its structural form, installation method, and the flow rate and type of the measured medium.
3. Diameter and Length Specifications
Common diameter specifications include Φ3×500, Φ4×500, Φ5×400, Φ6×600, etc. Common sizes for insertion thermowells include diameters Φ16mm, Φ22mm, Φ34mm, and lengths 300mm, 500mm, 1000mm, etc.
- Diameter: Select according to thermometer diameter and pipe size
- Length: Ensure the insertion depth can contact the measured medium
- Special types: Insertion RTD protection thermowell, waterproof thermowell, etc.
4. Material and Maximum Temperature
Material selection directly affects the service life and measurement accuracy of the thermowell. The maximum temperature resistance of different materials is shown in the table below:
| Material | Maximum Temperature | Characteristics | Applicable Scenarios |
|---|---|---|---|
| Alloy steel | 800°C | High temperature resistance, sturdy | High-temperature industrial furnaces, heat treatment |
| Stainless steel | 600°C | Corrosion resistant, durable | Chemicals, petroleum, pharmaceuticals |
| Copper | 400°C | Good thermal conductivity, easy to process | Medium and low temperature, food industry |
| Aluminum | 300°C | Lightweight, low cost | Low temperature, general industry |
Selection Steps and Precautions
Selection Steps
- Confirm the temperature range of the measured medium and select the corresponding temperature-resistant material
- Confirm the corrosiveness of the medium and select corrosion-resistant stainless steel or copper material
- Confirm the pipe interface thread, such as G1/2 female M20*1.5
- Determine the thermowell length according to pipe diameter and insertion depth
- Confirm the pressure rating and perform a hydrostatic test if necessary
Installation Precautions
- Ensure the thermowell insertion depth is appropriate and can contact the measured medium
- Ensure good sealing between the thermowell and the pipe or equipment to avoid gas or liquid leakage
- Regularly check whether the thermowell is worn or damaged, and replace it in time if necessary
- Regularly clean the inside of the thermowell to prevent dirt or impurities from affecting measurement accuracy
Maintenance and Inspection
Daily Maintenance
- Check whether the thermowell appearance is worn or deformed, and replace it in time if there is a problem
- Check whether the sealing performance of the thermowell is good, and deal with it in time if there is a problem
- Regularly clean the inside of the thermowell and keep it clean
- Regularly calibrate the measurement accuracy of the thermowell according to actual use conditions
Hydrostatic and Flaw Detection Tests
When there are requirements for pressure resistance and leakage inspection of the protection tube, the protection tube must be tested. The test pressure is 1.5 times the pressure resistance grade of the protection tube. When there are requirements for inspection of items such as wall thickness and eccentricity of the protection tube, radiographic flaw detection tests must be carried out according to user requirements.
Special Types and Stock Supply
In addition to conventional specifications, there are also special thermometer protection thermowells such as waterproof type and high-pressure resistant type, suitable for special use environments and measurement needs. During selection, it is necessary to choose according to the specific use environment and measurement needs to ensure the safe use and accurate measurement of the thermometer.
We provide a large amount of stock and welcome your purchase. For more information, it is recommended to consult relevant experts or refer to the product manual.
