Globe valve direction

[arash807]

Dear experts

As far as I know,the flow direction in globe valves is depends on valve application.in other word for shut off valves flow direction should be over the plug.and for throttling valves flow direction should be under the plug.
So why manufacturers show direction on globe valve body?

 

[gerhardl]

Most valves of globe and excentric (and partly for standard) butterly types, and other constructions (for instance needle valves), have a preferred flow direction. You can define a preferred flow direction as a direction where flow and closing (thightness at a given pressure) will be better than in the opposite direction. For som valves this direction will be compulsory; the valves are not constructed for the other direction, or give severe disadvantages if flow is reversed.

An arrow on the house will indicate for some cases recommended flow direction, but in most cases compulsory flow direction, and in any case 'be especially aware of mounting and flow direction'.

I can not remember coming across a globe valve where throtteling is recommended in opposite direction of normal flow direction. This will usually disturb the flow and give turbulence problems. Most globe valves meant (especially) for throtteling, can be equpped with regulating cones, all constructed for flow in the normal, preferred direction.

 

[arash807]

Thanks for your perfect and soon reply.