Straight Length Requirements for Thermowell

The mounting arrangements will be supplied with the equipment in the form of user instructions. These need to be followed to ensure the correct installation. If these are not to hand, the manufacturer may be reached by a number of methods; of them, the telephone is strongly recommended on the basis of its speed, its directness, and the interactive nature of the method of communication.

Thanks for the information..

But i am asking for straight Length on sides (Upstream & Downstream)of pipe where thermo well is mounted and not immersion length inside the dept of pipe..

As For Flow elements we have 2Xdia upstream and 1XDia Downstream.

On small lines, it is preferred to put the well in an elbow in order to get sufficient immersion length.

Or a tee. Good point.

But i am asking for straight Length on sides (Upstream & Downstream)of pipe where thermo well is mounted and not immersion length inside the dept of pipe..

As For Flow elements we have 2Xdia upstream and 1XDia Downstream.

Just the opposite of a flow meter or such. In the case of a thermowell you want as much turbulence as you can get in order to avoid a temperature gradient. The suggestions above for an elbow or tee placement are the best.

I have always used the rule of thumb that suggests the length of a thermo-well should be 10 times its diameter.

All thermowell sholud install at upstream. (after flow meter)

If your flow meter required straight length 10D downstream or 5D upstream, the thermowell should installed after the 5D length. You can check AGA 9 for gas application

Temperature sensors do not require a "conditioned" flowstream like many flowmeters do. Long lengths of straight pipe before and after the flowmeter exist to ensure large-scale turbulence (e.g. eddies, vortices) have dissipated so they do not skew the flowmeter's accuracy. Temperature sensors don't care, therefore no straight-length requirements are necessary.

Unless . . . you are installing a thermowell near a flowmeter, in which case the thermowell itself will *generate* vortices that can affect the flowmeter's accuracy. The AGA Standard #3 in the United States is one example of a formal standard addressing this effect, where a certain minimum distance of straight pipe is required between the thermowell and the flow element (orifice plate) in order to avoid flow-measurement errors.