Applications of Concentric vs Eccentric-Disc Butterfly Valves
Applications of Concentric vs Eccentric-Disc Butterfly Valves
(OP)
I wish to know the respective areas of applications for concentric-disc butterfly valves as oppose to that of off-centre disc butterfly valves.
Is butterfly valves used in water supply distribution mains? If yes shold it be concentric or eccentric type?
Is butterfly valves used in water supply distribution mains? If yes shold it be concentric or eccentric type?





RE: Applications of Concentric vs Eccentric-Disc Butterfly Valves
Traditionally butterfly valves are used in utility services (water, etc). This stigma is slowly being shaken off (supplier now call the high performance beasties rotary process valves)and now they are giving ball valves a run for there money in other applications.
For yours (water dist. mains) a rubber lined concentric would give average/good performance. A double offset valve would give superior performance, but is more expensive. Better (performance)still (and with the addtional cost implications!) is the triple offset, but I think unnecessary. these are now used widely in the North Sea for hydrocarbon service upto & including Class 600 (NPS 3 & above)for isolation. What was the question??!!
RE: Applications of Concentric vs Eccentric-Disc Butterfly Valves
In water distribution mains, how does one decide between sluice (or gate) valve and butterfly valve?
Is it true that for flow control, butterfly valves are better than sluice valve?
Is it true that concentric butterfly valves are better for tight-shut?
Hope you or anyone could help.
RE: Applications of Concentric vs Eccentric-Disc Butterfly Valves
A metal seated valve will last longer and has the potential for less problems than a soft seated or rubber lined valve.
The choice is down to all your required parameters. Butterfly valves are cheaper than gate valves, and can be of wafer type.
It is generally accepted that gate valves are used for isolation (on-off) valves whereas butterfly valves are both throttling and isolation.
Tight shut off - with a metal seated valve (i.e. gate, aslthough you can get soft seated gate) tight shut off is obtainable, but the testing standards allow for some leakage.
Soft seated valves should always be zero leakage, unless the seat is damaged.
Bear in mind this is all from an Oil & Gas background / experience. Hope this helps