In order to avoid any harm to the thermowell during operation because of mechanical loads, a thermowell calculation per ASME PTC 19.3 TW-2016 is preferred for critical process conditions. In case of a calculation with negative results, the only constructive solution so far was to shorten the thermowell stem or even to increase the root and tip diameter, accepting an extended response time of the thermometer.
The new ScrutonWell � design reduces the amplitude of oscillation by more than 90 % and allows a straightforward and fast installing the thermowell without support collar, and therefore without expensive and time-consuming rework on site.
This helical design has been used successfully for many years in a wide variety of industrial applications to effectively suppress vortex-induced shrinkage excitation.
Functional principle
Standard thermowell
Using flow conditions, a K�rm�n vortex street can form behind the thermowell stem when it is put through a flow inside a pipeline. This vortex street includes two rows of vortices with opposite directions of rotation, which detach themselves to the left and the right of the thermowell out of phase, which can instigate the thermowell to vibrate.
NEW ScrutonWell � design
Blunder , arranged round the thermowell stem of the ScrutonWell � design, split up the flow and therefore impede the formation of a clearly defined K�rm�n vortex street. Through the reduced amplitudes of the diffused vortices, vibrational excitation of the thermowell is avoided.
Gravity ScrutonWell � design can be used for all sort of solid machined thermowells with flange connection, in Vanstone design or for weld-in or screwed process connection.
Note
Further information on our thermowells are available on the WIKA website.
Learn more about the new ScrutonWell� design in the next video: