Ball Valves for District Heating 1

[paramodv]

I am researching trunnion ball valves for undeground district heating applications: 20-32", full bore, weld ends, water at 320F and 240 psi. What manufacturers/types provide the best cost/benefit ratio for that application considering that it is a relatively low pressure, not highly corrosive environment, water not gas, etc.

 

[TBP]

Why not butterfly valves?

 

[RXH]

TBP makes a good point. Butterfly valves will make a more cost-effective solution even if you go with the top-of-the-line triple eccentric metal-seated butterfly valve.

However, if you still wish to pursue the ball valve, I would suggest the following spec assuming that the water is treated and is non-corrosive: Split-body, trunnion mounted, carbon steel body with carbon steel nickel/chrome plated trim, soft seated. This is the most economical combination. If your medium requires a more corrosion resistant trim, then specify SS 316. In any case, you will need to verify that the soft seat and seal materials can meet your P-T ratings.

 

[paramodv]

Well, I do not know why not butterfly valves. Why are trunnion ball valves used for district heating applications?

 

[TBP]

Are you putting the valves in manholes, or are they being direct-buried?

As far as who has the best valves goes, I'd check into who has the best local representation. Even the best manufacturers have the "company idiot" somewhere in their organization. If he happens to be the rep for your area, and you get stuck with him, you'll have no end of problems, no matter how good the product is.

 

[MikeONeill]

The difference between a full-bore ball valve and a class 300 butterfly, in terms of Cv is HUGE. A ball valve manufacturer you may wish to try is PBV of Houston, Tx.

http://www.pbv-usa.com/

Mike



Mike