Full Bore or Reduced Bore Ball Valves

[From:http://instrumentation.web.id] [Author:admin] [Date:11-08-24] [Hit:]

Full bore ball valve is a valve that the hole diameter of its ball is the same size with the pipe size. Reduced bore ball valves is a valve that the hole diameter of its ball is not the same size with the pipe size. In minimum the reduced ball valves ball diameter are one size lower than the pipe size i.e. 4 inch pipe and ball diameter is 3 inch (usually symbolized as 4 x 3 inch ball valves). From its definition we can quickly know that the full bore will have less pressure drop and reduced bore will have more pressure drop since reduced bore is just like a restriction orifice that narrowing at the middle part. So when full bore or reduced bore ball valves will be used?

As default for offshore platform application where weight and cost is matter, the reduced bore ball valves should be used. Reduced bore ball valves is lighter in weight compare to full bore ball valves. Also, the reduced bore ball valves might be used in application where the pressure drop through the valves is not significantly effect the services (at most application the pressure drop through reduced bore ball valve is very low).

For actuated ball valves that used to isolate vessel or any fluid services, reduced ball valve usually used for production separator, suction scrubber, glycol generator etc. While full bore actuated ball valves usually used for blow down, piggable line, production manifold, pipeline etc. Actually for blow down or any similar application, we can also use a reduced bore since the pressure drop usually isn’t significant. But usually it comes from the project specification that requires it to be full bore. It differs with piggable line that must be in form of full bore to allow the pig going through the valves at pigging activity.

Below is the illustration of full bore ball valve and reduced bore ball valve from Valbart.


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