In order to avoid any damage to the thermowell during operation due to mechanical loads, a wake frequency calculation per ASME PTC 19.3 TW-2016 is recommended 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 to increase the root and tip diameter, accepting a longer response time of the thermometer. The only other alternative up to now was to use a support collar to stabilise the thermowell stem inside the flange nozzle. This variant required an on-site machining of the collar to assure an interference fit in flange nozzles.
The ScrutonWell® design reduces the amplitude of oscillation by more than 90 % 1) and allows an easy and fast installation of the thermowell without support collar, and thus without expensive and time-consuming rework on site.
The WIKA ScrutonWell® design has been tested and approved by the independent laboratories TÜV NEL (Glasgow) and the Institute for Mechanics and Fluid Dynamics (Technical University of Freiberg).
The ScrutonWell® design can be used for all kind of solid-machined thermowells with flange connection, in Vanstone design or for weld-in or threaded process connection.
This helical design has been used successfully for decades in a wide variety of industrial applications to effectively suppress vortex-induced vibration excitation.
1) Journal of Offshore and Mechanics and Artic Engineering Nov 2011, Vol 133/041102-1 by ASME