No wet legs on steam flow DP transmitters?

C

Thread Starter

Carl Ellis

I'm an old guy and for decades, the prescribed method of DP transmitter mounting on a steam line has been BELOW the steam line with water filled wet legs to protect the transmitter from the steam heat.

Amazingly, Rosemount just re-wrote the rules (for certain conditions).

The way I heard the story is that someone at Emerson ran across a DP transmitter installed above the steam line, not below, obviously with no wet legs, with just a coplanar manifold valve assembly on the top of an averaging pitot tube.

It had been running for about a year, with no apparent damage. Emerson sent people to investigate and found it to be true.

They've released this white paper
http://www2.emersonprocess.com/siteadmincenter/PM Rosemount Documents/00870-0200-4809.pdf

Check out the IR image of the transmitter on page 8.

My source attended an Emerson's annual customer conference and heard about it there.

I'm shaking my head. Who'd a thought?
 
can see how some horizontal lines might be compatible with liquid free connections, but hardly a cure-all...given all the things that can and do happen in most operating environments it would be pretty iffy in some applications where the steam temperature is extreme.
 
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