- “Short” immersion lengths reduce drag and stress at root.
- “Fat” thermowells, at least at the root, increases the strength of the well at the weakest point of its structure. Enlarging the tip decreases the wake frequency of the thermowell, often without significant reduction to the installed natural frequency. Since keeping your thermowell’s wake frequency significantly below its installed natural frequency is key to avoiding vibration induced damage, enlarging the tip can often cause your thermowell to achieve longer immersion lengths without encountering dangerous resonance conditions induced by Von Karman vortices.
- “Slow” process fluids are unlikely to cause a thermowell to approach an unacceptable natural frequency or experience an unacceptable stress at its base.
For optimal temperature measurement - long, slender and fast.
- “Long” thermowells avoid or reduce the effects of stem loss error.
- “Thin” thermowells decrease the response time of your sensing element for the same reason that it takes longer to fry a Thanksgiving turkey than it does a chicken wing.
- “Fast” process fluids provide optimal heat transfer again accelerating the response time of your sensing element.
For the best blend of the strength and measurement, try this software. Applying the PTC 19.3 standard, it provides you with maximum theoretical immersion lengths and flow rates so that you can design your thermowell with an eye towards both strength and measurement requirements without giving short shrift to either. For special reports dealing with corrosion allowances and more,
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