Thermowell Design Methods and their Implementation in an Expert System

  • Heinz Sigler

    Student thesis: Doctoral Thesis


    This research programme was carried out in order to establish design methods and procedures for thermowells and implement these methods in a computer-based expert system. Thermowells are accessories for the temperature measurement instrumentation and they have to protect the temperature sensor from hazardous environments at high pressures and temperatures. The sensor also needs protection from the flow of the fluid it is immersed in as it can cause the sensor to vibrate and subsequently damage it. Thermowells have to be designed in such a way that they can resist the vibration caused by the flowing fluid, do not collapse due to the surrounding pressure and the thermowell's material has to be compatible with the fluid to avoid corrosion of the thermowell. At the same time they have to transfer the heat of the fluid to the sensor to enable the temperature measurement.

    A literature review was carried out to establish the available methods and procedures concerning thermowell design. The procedures that deal with the calculation of the natural frequency of thermowells, which is required to ensure the thermowell is not damaged by vibration, were verified using practical vibration analysis techniques.

    After establishing the appropriate procedures to determine the vibration, pressure, stress and thermal aspects concerning thermowell design, they were implemented in an expert system. The software package KAPPA-PC was used to develop the application. After careful testing and elimination of different errors encountered during the testing phase, an expert system was delivered that carries out the analysis of a given thermowell design and also designs a thermowell for a specified application.
    Date of AwardSept 2001
    Original languageEnglish
    SupervisorGiuliano Premier (Supervisor)


    • Thermowells
    • expert system
    • temperature measurement instrumentation

    Cite this