Question of Thermowell

[sxyt]

Could someone help me understand more about Thermowell,
1: why minimum pipe is DN100 for Thermowell?
2: is there any spec saying the length of Thermowell for tank?
3: how to caculate it, stress? frequency? any software there?
Thanks in advance

 

[danw2]

>3: how to caculate it, stress? frequency? any software there?

There's been an updated standard for thermowells, the newly revised ASME PTC 19.3 TW (2010) standard. It addresses frequency/vibration issues.

A thermowell vendor, JMS has a free on-line software application after web registration:

http://www.jms-se.com/swiftycalc.

 

[DRWeig]

Try the folks at JMS Southeast, Statesville, North Carolina, US -- they have a free calculator that's really good.

http://www.jms-se.com/

Good on ya,

Goober Dave

(I'm a former customer, not somebody who works for JMS)

 

[sxyt]

Thanks, still waiting for more details.

 

[JLSeagull]

Different installation methods permit some variation in the minimum line size etc. Also, the pipin connection such as flanged is normal for me but other ndustries may have other options. You could install the TW in a line smaller than NPS 4 in an elbow. Where practical piping could change from NPS 2 to larger pipe just for the TW if practical. Some clients permit TW style installations (sample probes) at NPS 3 for flanged connections. Such probes are a TW with the end cutoff.

I think that the new calc is LOTS more conservative than previous.

 

[hacksaw]

http://www.tempsensor.net

may still have a simple code available, don't know if it is up to date with the new thermowell standard, though the natural frequency calculation appears to be very good for none standard designs

 

[sxyt]

Thanks, someone can tell me any spec saying the minimum length of thermowell is 2.5" and where to download the cal software?

 

[hacksaw]

there is no minimum length, the national codes restrictions are meant for industrial services

ring up any thermowell supplier in your area, i.e any industrial piping supply they'll sort you out with hardware and software.

if you need google help type in "thermowell software"