WHY USE VELOCITY COLLARS?
The goal of a velocity collar is to reduce the effective unsupported length of a thermowell. In theory, this helps accomplish two things:
1. Eliminates vortex-induced failures. Shorter unsupported lengths raise the natural frequency of a thermowell, which allows higher flow rates to
avoid causing the thermowell to vibrate at its resonant frequency.
2. Reduces bending stress. Process fluids create a drag force on thermowells, causing them to bend. A shorter moment length will reduce the stress at the root of the thermowell, reducing failures.