Butterfly vs globe and/or ball valves?

Question

Which is best for temperature control of a large water coil that requires high shutoff pressure?

Answer 1

I am an engineer providing mechanical planning for various industrial/manufacturing plants in the Kansas City area. The practice of controlling temperature through valve adjustment is called throttling. While throttling can be achieved using a butterfly valve, a globe valve is the standard application. A ball valve should not be used for throttling.

Answer 2

Globe Vs Ball Valve

Answer 3

The comparison between these valves is made at full open to compare each valve type minimum restriction. Needle vales have the highest pressure drop. By design a needle valve has a narrow and sharply tapered seat and disc for precise flow control. Even when fully open the annular opening of a needle valve is the smallest of the listed types when compared to other comparably sized valve types. (Smallest opening = Highest restriction)

Answer 4

You did not state the size of the valve. Ball valves designed for control come in limited sizes. You should present your problem to a control valve manufacturer such as Fisher Controls. (they have a web site).



It should be noted that very few control valves give a complete shut off due to their constant throttling and the resulting wear and tear on the seating surfaces.

Answer 5

Definately a screw ball valve. It is more precise and can fully close under high pressure. A butterfly valve will work however will not last long before loosing its seal if opened and closed frequently.