A thermowell is a protective sheath designed to house a temperature sensor (such as an RTD, thermocouple, or temperature probe) in industrial applications. It isolates the sensor from direct contact with the process fluid while allowing accurate temperature measurement.
Why Use a Thermowell?
✅ Protects the sensor from high pressure, corrosion, and mechanical damage.
✅ Allows easy maintenance and sensor replacement without stopping the process.
✅ Enhances durability by reducing sensor wear from flow and vibration.
✅ Improves accuracy by stabilizing temperature readings in turbulent flow conditions.
Types of Thermowells:
1. Threaded Thermowell
- Has a screw-type connection for easy installation and removal.
- Used in low to medium pressure applications.
✅ Application: HVAC, water systems, general industrial use.
2. Flanged Thermowell
- Features a flange connection for a secure and leak-proof seal.
- Suitable for high-pressure and high-temperature environments.
✅ Application: Oil & gas, chemical plants, power plants.
3. Welded (Weld-In) Thermowell
- Permanently welded into the pipeline for maximum strength.
- Used in high-stress and high-temperature applications.
✅ Application: High-pressure steam lines, critical process industries.
4. Socket Weld Thermowell
- Has a socket weld connection for a secure fit.
- Ideal for high-pressure and high-temperature applications.
✅ Application: Petrochemical, energy, and refinery industries.
5. Van Stone (Lap Joint) Thermowell
- A two-piece design with a separate flange that allows easy installation and removal.
- Used where adjustability and cost-effectiveness are needed.
✅ Application: Heat exchangers, chemical processing.
Selection Factors:
✔ Process Temperature & Pressure – Higher values require stronger materials and connections.
✔ Fluid Corrosiveness – Chemical resistance determines the material choice.
✔ Flow Velocity – Fast-moving fluids need vibration-resistant designs.
✔ Insertion Length – Proper depth ensures accurate temperature readings.