High integrity seals

[paddy1385]

Hi,

My project specs says we need to use gate valves with high integrity seals. So I have below queries on this.

What is meant by high integrity?
If it means tight shut off, then can valve with Leakage class VI be said as high integrity valves?
Are all Gate valves are high integrity valves only.

 

[LittleInch]

Hmmm, just what you don't need when you're trying to buy something - vague terminology

what "high integrity" means is open to debate and misunderstanding. What I suspect it means is that the user wants a valve which will open and close repeatedly, probably against a flowing fluid with unknown particles and miraculously seal 100% with no leaks every time - yeh right....

The best you're going to get is probably some sort of expanding gate valve where the elastomeric seals are protected from movement and where the gates move off them before moving up. Very good long term sealing and has the ability to drain the middle portion to prove sealing. e.g.

https://www.c-a-m.com/products-and-...am-valves/wkm-pow-r-seal-expanding-gate-valve

Valve seal class ratings I always feel are a bit of a misnomer as they only really apply during testing and don't (IMHO) really give any long term integrity information. I think lots of people get very hung up over getting a valve which seals to some incredible limit on test ignoring how it will actually perform in the field.

So you need to question the person saying this to try and see what he or she means and whether they actually know or are just spouting some requirement from others who equally don't really know.

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

 

[paddy1385]

Thanks LittleInch
Expanding gate valves were the first thought came to my mind too, but when I asked suppliers about the same, they told me that their valves are with high integrity seals & they are normal gate valves only. So can all Gate valves be said as High integrity valves?

 

[LittleInch]

In a sense yes as I don't know many that the vendors will claim to sell "low integrity seals"....

That's the whole problem with vague definitions - everyone can claim their seals are "high integrity" as all that really means is that they don't fall apart after a few operations and aren't in the flow path or exposed to lots of contact and movement unlike say ball valve seals

There aren't many expanding gate valve suppliers so vendors will give you what they supply and then claim it's as good as any other. Unless you have direct operating experience of different valves to use and compare, it is very difficult to rank different vendors valves from another one of the same type and vague definitions like "high integrity" don't help either.

As with most things in life, ultimately you get what you pay for, just here the person paying often doesn't see the benefit / cost of a "better" valve compared to a lower quality one which comes much later.

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

 

[Compositepro]

It is possible that the intent was to ask for low-emission valves.

 

[LittleInch]

That's a good point, which seals does it refer to?, stem seals or valve seals?

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

 

[georgeverghese]

Another interpretation may be that these valves need to be fire safe?

 

[gerhardl]

'High integrity seals' will not be found in any norm, as LittleInch originally said. The wording can be read as 'standing firm to true original given rules,' which (also as LittleInch says) leaves us left in the fog (if this has some meaning in English.)

Any explanation that does not come from the originator will be pure speculation. There is only one source for the truth, everything else will at best be guesstimates. Guesstimates are not good eneough to offer technical items!

(Good luck !)

 

[mbelly84]

in my experience i've seen this terminology "high integrity seals" referred to thermoplastic seals (lip seals) which are intrinsically resistant to explosive decompression, unlike elastomers.

but again, this is interpretable in so many ways.