Valve Replacement 2

[Valving]

Hi to all,
I am working on a project where we are trying to replace
some Korean valves.
Valves we will use has shorter flange to flange dimensions
thus we need to arrange a solution for the difference.
I believe there are some experienced ones that would recommend
the most economical or feasible solution.
A spool piece could be manufactured or maybe flange
adaptor etc. could also work.
Thanks in advanced for ideas.

 

[LittleInch]

How much shorter? Were the originals made to a different code? What sort of sizes / pressures are you dealing with?

Can you modify the pipework instead? How many locations?

Give us a bit more information and you may get much more back in return.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Valving]

Sizes are different. Design pressure : 16 bar
For example, 1200 mm, 1400 mm.
We will replace with Awwa c504 valves
Differences vary. Thats my concern.
Pipings are all inside valve chambers so modifying is not possible.
I considered ductile iron or steel spool pieces but
I can not be sure how total lengths will result.

 

[LittleInch]

Your minimum difference which can be accomplished by two flanges welded back to back is your start point. Anything less than that needs a spacer. Anything more needs a flange back to back plus a spacer up to max of 50mm. Then use a WN flange plus spool with a slip on flange so that you can vary each one.

Not easy as each one will be different.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[ricklts]

Knowing as little as you have told us, how about using short lengths of the appropriate sized/schedule of piping with slip-on flanges welded at the cutoff points?

 

[pennpiper]

The information we need to help you is very simple.
How much shorter is the new valve than the original valve?

Or to say it a different way:
What is the face-to-face dimension of the original valves (by size)
and
What is the face-to-face dimension of the replacement valves (by size)

If I knew that I would be able to make a suggestion;
Such as, consider using Bleed Rings with a face-to-face dimension to make up the difference.
Do you know what a Bleed Ring is?
Look here if you do not know -

http://www.lrspecialtymetals.com/Default.aspx?tabid=744975

p.s.: You can order them without the Tap connection or you can just plug it.

prognosis: Lead or Lag

 

[zdas04]

I've used spacers (usually bleed rings, I like having places to stick gauges) when I had to fill a reasonably sized gap. The problem comes when the new valve is longer than the gap. What I've done every time in that case is:
[ul]
[li]Verify that the new valve is API 6D so I will never have to do this again[/li]
[li]Evaluate whether the valve chamber has to stay or not (often you can get rid of the damn things easier than you think)[/li]
[li]Evaluate whether you should add anything (like vents/drains)[/li]
[li]Dig up the entire valve chamber and 1/2 joint either side of it (trying to work with pipe in a bind never saves money or time, dig a hole that makes sense)[/li]
[li]Make up a fabrication with the valve inside flanges with random length pipe stubs on both sides (and any vents/drains)[/li]
[li]On turn-around day make two cuts, two welds, and zero bolt ups (I try to never do a bolt up with gas shut-in if I can help it).[/li]
[/ul]



David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"