Flow Tests of Two Thermowell Designs

Client name: WIKA Alexander Wiegand SE & Co. KG 

Industry: Chemical and Process

Profile: TÜV SÜD National Engineering Laboratory’s oil flow measurement facility was used to help one of Europe’s leading manufacturers of measurement equipment to assess the performance of an innovative thermowell design. This project highlights one of the many ways in which TÜV SÜD National Engineering Laboratory helps companies develop a wide range of measurement technologies.

Business challenge: A thermowell is a hollow piece of metal that protects temperature sensors that are installed in many industrial situations. The devices can, for example, protect temperature sensors from the negative effects of fluid flow, including corrosive media, physical impact, or high-pressure gas or liquid. In addition, thermowells allow users to remove the temperature sensor for replacement, repair, or testing without the need to “open-up” the process. They are used and in many different industries and sectors, such as food, nuclear, pharmaceuticals, commodity and fine chemicals, oil and gas.
When fluid flows past a thermowell, low pressure vortices are formed in the wake downstream of the well. The vortices detach periodically from each side of the well at a vortex shedding frequency. When vortex shedding frequency approaches one of the natural frequencies of the well, resonance can occur. This ultimately increases the vibration forces and can lead to the mechanical failure of the well.

Our approach: In conjunction with the instrument manufacturer, TÜV SÜD National Engineering Laboratory undertook a comprehensive test programme in their oil flow measurement facility examining a range of flow conditions using both a standard thermowell and the innovative new design (ScrutonWell®). The levels of vibration and dynamic stress, alongside high-speed video footage was recorded during the tests.

Our solution: A comprehensive test report was documented and issued to WIKA. The ScrutonWell® was designed to reduce oscillations compared to the standard thermowell. Utilising the test facility and other measurement instrumentation, the tests demonstrated a significant reduction in vibration of greater than 90% in vibration.

Business benefits: The testing was of major benefit to WIKA and their stakeholders as it provided evidence that their new thermowell design exhibited a significant reduction in oscillation compared to a standard thermowell.

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Related services: National Measurement System | Flow measurement