How would you approach this vendor? 1

[TugboatEng]

I have a friend that is having issues with a fitting leaking on a valve. The fitting is installed on a curved surface. The spec calls out BSP so I informed my friend to contact the vender and ask if it's parallel or taper. This is the vendor's response:

Clearly they have no interest in resolving the issue.

 

[LittleInch]

BSPP means BSP Parallel so the vendor has answered your question.

What more do you need?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[mfgenggear]

is the thread acceptable to a go & no go gage
if the thread is leaking there is a problem, time to do a failure analysis.

 

[TugboatEng]

The problem is that they're using a dowty washer to seal on a curved surface.

 

[LittleInch]

Is it me or does it look like the tapping isn't at 90 degrees to the pipe?

Or has had a bit of a hit?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[hydtools]

Nothing wrong using Dowty seal as long as the surface curvature is not out of the range of the seal squeeze range. Might have more reliably sealed with a full diameter spotface.

What do you expect from the vendor?

Ted

 

[IFRs]

You can flatten the outside of the cylinder if needed...

 

[TugboatEng]

The obvious answer to this problem would be for the manufacturer to incorporate a spot face into the design. I was just curious how others would proceed after the manufacturer dropped the "we've been doing this for 40 years" line as that shuts down the conversation.

 

[3DDave]

Not much to do. It's possible that in the 40 years someone made a change and the new guys didn't understand what made it work before. Or most customers have the part spot-faced because it always leaks and they really don't know.

 

[mfgenggear]

The question is it a design flaw or defect. I don't know the design. I will take comments from other post.
A proper response should have been please return the product for inspection.

As simple this product is, it failed.
Not familiar with dowry washer as it is not used in my type of work.
It could be the washer is at fault or
It was installed incorrect or wrong washer was used

 

[Artisi]

As noted by LI, is it at 90 degree, doesn't look like in the photo?
Noted by hydtools, spotface or partial spotface would be advantages.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[mfgenggear]

Just a note a spot face on a diameter will be elliptical. Major and minor diameter.
And must be deep enough for the face to clean up. So there has to be enough wall thickness.

 

[mfgenggear]

There is a possibility the seal was damaged from improper installation and
Damaged the seal. Which is why visually it appears tilted.

 

[GregLocock]

Yeah it does look skewwhiff. A horizontal section of the washer and cylinder on the bolt axis would show whether the rubber seal is adequate for the radius of the cylinder. The guideline in the category suggest a flatness of better than 0.08 in 25 mm is required.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[3DDave]

Why would a spotface be elliptical? It should be circular or incompletely circular with straight boundaries where it is incomplete. A countersink would appear elliptical, but it's a 3D curve edge and only elliptical by projection.

 

[TugboatEng]

This is a project a friend is working on and be asked me about it. It seems that many or all of these units are leaning. It even appears in some other pictures that a sealant was applied to the threads which should not be done with a dowty washer. If I had to speculate I would guess that whomever machined this things added the spot face automatically and that person has either moved on or a new vendor is performing the work.

 

[FacEngrPE]

Try assembling with an anaerobic sealant (generic loctite). It should glue the leak path shut, and if you use a lower strength version it should be removable with hand tools. Yes I realize this is contrary to the intended design of the BSP fitting.

 

[mfgenggear]

3DDave
because it's on a diameter surface it's elliptical, on a flat surface it would of course be circular.

 

[hydtools]

FYI


Ted