In order to avoid any harm to the thermowell during operation due to mechanical loads, a thermowell calculation per ASME PTC 19.3 TW-2016 is preferred for critical process conditions. In the event of a calculation with negative results, the only real constructive solution so far was to shorten the thermowell stem or to raise the root and tip diameter, accepting a longer 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 thus without expensive and time-consuming rework on site.
This helical design has been used successfully for decades in a wide variety of industrial applications to effectively suppress vortex-induced shrinkage excitation.
Functional principle
Standard thermowell
In certain flow conditions, a K�rm�n vortex street can form behind the thermowell stem when it’s subjected to a flow within a pipeline. This vortex street includes two rows of vortices with opposite directions of rotation, which detach themselves left and the right of the thermowell out of phase, which can instigate the thermowell to vibrate.
NEW ScrutonWell � design
The helical strakes, arranged round the thermowell stem of the ScrutonWell � design, break up the flow and therefore impede the forming of a clearly defined K�rm�n vortex street. Through Embarrassing reduced amplitudes of the diffused vortices, vibrational excitation of the thermowell is avoided.
The NEW ScrutonWell � design can be utilized 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: