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Out of Round 8ft diameter butterfly valve

Out of Round 8ft diameter butterfly valve

Out of Round 8ft diameter butterfly valve

(OP)
I need some creative ideas on how to repair/modify an 8ft diameter butterfly valve that is out of round (probably that way at initial construction). Valve isolates cooling water to section of power plant condenser. Leakage is too great to allow condenser maintenance downstream. Repair/modification would have to be done in situ. Any ideas or people to talk to.   

RE: Out of Round 8ft diameter butterfly valve

I.e., without shutting down everything, right?  Yikes.

Maybe you can reduce the flow without repairing the valve..   Can you find a way to insert and inflate a big-ass tractor inner tube or bladder upstream of the almost- closed butterfly?

... probably violates all kinds of safety rules.


Mike Halloran
Pembroke Pines, FL, USA

RE: Out of Round 8ft diameter butterfly valve

What do you mean out of round? Are you sure it is not the design pivot excentricity in the valve to make it seat better against the valve seat when closed sagainst the upstream water pressure? Maybe it is just the valve seat that is out of place. Or maybe the valve is installed backwards (flow direction opposite valve design flow direction).

Are there other upstream valves that you can open to divert or reduce the flow to the bad valve to the point that repair work can be performed.

RE: Out of Round 8ft diameter butterfly valve

Do you have a picture of an 8' dia butterfly?  That has to be a site to see.

If you worried about repairing something downstream, there are companies out there that can freeze water inside the pipe so you can do repairs and maybe add other isolation valves so you don't have to do this again.

Do a search on here I think it was discussed not to long ago.  I am sure it isn't going to be cheap though.

Zuccus

RE: Out of Round 8ft diameter butterfly valve

Something silmilar occurred twenty some years ago, hence details are vague
The valve was repaired at make-shift repair shack/lean-to at the site.
The valve fabricator had bolt holes at one flange end filled with weld filler metal and holes were redrilled thru undisturbed steel to suit field bolt-up requirements.
I do not recall the intended service of the valve but it must of been very low pressure system for client to buy off on repair. At very large diameter the numbrer of bolt holes can be overwhelmiing

RE: Out of Round 8ft diameter butterfly valve

As noted, safety is your biggest problem.  I can't imagine anyone who is going to get inside the condenser to work on the valve with even just static head against the valve, even in scuba gear!  Any repair is most likely going to require that the disc is partially open, away from the seat. Once you have the pressure off and water drained, there are any number of ways to force the valve body back to round, but replacement may be quicker and cheaper, and ultimately more reliable.

RE: Out of Round 8ft diameter butterfly valve

The mechanic's friend, Bar's Leaks:

http://www.barsproducts.com/

not sure if comes in tank car packaging.


RE: Out of Round 8ft diameter butterfly valve

Is it possible that just backfill or supports are moving it out of round, and could be adjusted to hold it round?

RE: Out of Round 8ft diameter butterfly valve

I don't think this valve is buried; I'd guess it's in the basement of the power plant near the condenser.  Probably a half-mile of 96" pipe to drain?!

RE: Out of Round 8ft diameter butterfly valve

I would give these people a call. I've used their products though not in your size.
I haven't checked lately but there may be places you can rent a plug. Also there are several other people that make large pipe plugs with inflateable seals.

http://www.sealfastproducts.com/products.htm

RE: Out of Round 8ft diameter butterfly valve

When is your next refueling outage for this unit?

rmw

RE: Out of Round 8ft diameter butterfly valve

How has the 'unround condition' been verified? If tested droptight before installation, the 'unround' condition will have to have been caused by mechanical forces inside (water hammer, higher pressure than allowed) or outside (unproper fastening or weight from unsupported parts of pipeline construction) over time. May occur, but more unlikely than sealing damage or sealing hardening over time.

In my opinion: very difficult in any case to repair inline. Shut-down and replacement recommended.

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