Instrumentation plumbing 1

[Thedroid]

Where can I find a good book on different plumbing techniques for process measurement. I deal with mostly dry pressure and draft instruments and would like some info on the accepted ways of plumbing these devices. I've been tasked recently with designing new plumbing to eliminate some of the lines that plug constantly, and to come up with better designs. All of new designs have worked well so far, but I used common sense for the plumbing, not any accepted practices that I know of.

 

[JLSeagull]

For starters, review API RP 551, Process Measurement Instrumentation. This standard reflects common installation practices. However, the standard is drected at the refinery business not draft instruments.

 

[danw2]

I've got about 100 process instrumentation books on my book shelf at work but I'm not sure I can recall anything on plumbing draft pressure instruments. Not that it isn't buried somewhere, but I just can't recall it.

I've got 2 in mind, where I'd look first. Let me see if either yields anything.

Dan

 

[JimCasey]

Draft instrument sensors will monitor gas. If you get a 1" slug of condensate and you're trying to measure 2" of draft, that will be a killer error. So, the tubing should slope downward toward the process so that any condensation will drain back into the system. The tubing should be large enough that it will not be obstructed by any droplets. (3/8 is better than 1/4, thinwall is better than heavy wall). Slope should be agressive. Normal instrument lines use 1" per foot. I'd go at least 3" with draft instruments. and keep the laterals as short as possible.

 

[roydm]

"I used common sense for the plumbing, not any accepted practices that I know of", Sounds to me like you don't really need our help.
Roy

 

[Thedroid]

Just looking for books that have some fundamentals of process piping. Seems to be a lost art, or maybe I just haven't worked in a plant where this is critical.

 

[danw2]

Process Instrumentation Manifolds: Their Selection and Use A Handbook
Author: John E. Hewson (Hardcover, 1985)
ISBN-10: 0876648537
ISBN-13: 9780876648537
Apr 1985
343 pages
Publisher: ISA

http://www.isa.org/Template.cfm?Section=Books3&Template=/customsource/isa/StoreIntro/books.cfm

Industrial Instruments and Control Piping for steamfitter pipefitter
Merkle Press, copyright 1961, various editions

 

[KiwiMace]

I spent four years as an apprentice instrument tech and I can't remember ever seeing those books, but the picture on the front cover of the green one was stolen straight from our photocopied class notes!

 

[roydm]

KiwiMace, I hear you. Most designers I know keep a copy of installation details from each of the engineering firms they have worked at over the years.
Working in maintenance for a while also helps eh!
Ex ET Railway workshops, Wanganui, Now vancouver BC

 

[JLSeagull]

The photo resembles the 1950's version of API RP 550. Note all of those leaky screwed fittings using hard pipe and unions. That obsolete standard was replaced by API RP 551.

 

[KiwiMace]

This 1950's standard was still clearly being used in 1980's New Zealand!

 

[Thedroid]

Thanks. I'm going to look into getting those books.

 

[hacksaw]

draft level meas. with impulse lines is a toughy, you cannot assume anything will just work, as JimC points out, in some cases 1/2" is not large enough even for vertical drops

 

[Rockfort]

Refer to instrumentation books by Bela G Liptak or by Andrews. Both give good guidelines on instrument impulse lines

 

[danw2]

Nothing specific to draft range, but an excellent guide, nonetheless:
Best Practice Guide: Impluse Lines for DP Flowmeters

Download from site requires free registration

http://www.flowprogramme.co.uk/docs/view-doc.asp?File=BPG_2002_2005_ImpulselinesDPMeters.pdf

Best Practice Guides > Flow programmes > Impluse Lines for DP Flowmeters

 

[danw2]

Specific recommendations for draft range installation:

http://www.sea.siemens.com/instrbu/docs/pdf/ADSITRPDS3-1r1.pdf