plug valve

[LeCadre]

I am involved in developing a lift and turn plug valve for sand/slurry application. My job is to functionally test our design and give feedback.
The customer spec and leakage rate for the seat test seems to be based on Ball Valve results and not reachable for plug type valves.

Does anyone have experience with plug type valves? What is a reasonable leakage rate for production testing? The Plug and the seats are stellited.

Also since this valve is to be used in Dredging application it might not need a very tight leakrate on the seat test? (IMHO)
What is your general idea of 'my honest opionion'?

I could use feed back, customer is sending a delecation to visit our works today.

Thank you,

Caspar

 

[hsbcn]

hi LeCadre:

check our JLSeagull's post and reference to SP-78-1998 as per the following thread:

http://www.eng-tips.com/viewthread.cfm?qid=210466

hope this helps!

Heather's focus: Alloy Valves Duplex Valves Super Duplex Valves Monel Valves Inconel Valves [link titanium-valves.com]Titanium Valves[/url] & 6 Moly Valves

 

[LeCadre]

Thanks for your reply. The one you refer to is about the 'old' bubble tight or 'zero leakage' discussion. I recently had some issues with a third partty inspector about this subject.

This valve I am talking about isn't bubble tight and doesn't have zero leakage by any standard.
It is currently at 7 ml/min with liquid (= 0.43 Cubic inch per minute). Which is far from bubble tight, but INHO more than enough for sand/slurry applications.

We aren't very active in the dredging world. I am looking for some reference.

 

[gerhardl]

Your comparing reference could be some of the plug-valve producers in general, not only the lift and turn-types.

If your customer comperes to double eccentric plug-valves with soft sealings, theese could be supplied drop thight up to ceratain limits and pressure classes because of the soft sealing and double eccentric construction.

With metal seated valves you will always have a leakage.

You could probably search out others, but here is one possible link for lekage comparisons:

http://www.dezurik.com/Products/Main.aspx