Globe valves are a kind of valves that axis of stem is vertical to the sealing face of seat. The stem has relatively short stroke and reliable cutting off. Nevertheless, globe valves are quite suitable for cutting off or regulating media and throttling.
Once a globe valve opening, its seat does not contact with sealing face of disc any more. For that sealing face has less physical deterioration. Due to seat and disc convenient for repairing or replacing, valves do not need to be installed from the pipe when replacing components. This is quite applicable when valves are welded with pipeline as body. When media pass through globe valves, flowing direction changes, globe valves have higher flow resistance than other kinds of valves.
Types of globe valves in common use:
1) Angle globe valves: The flowing direction changes only once, when media passing through angle globe valves. So, the pressure drop in angle globe valves is lower than that of conventional globe valves.
2) Straight globe valves: In straight globe valves or Y- shape globe valves, passageway inside body forms a slash with main passageway. Flow condition can be destroyed less, compared with conventional globe valves. So pressure loses relatively low, when media passing through straight globe valves.
3) Plug globe valves: Plug globe valves are a kind of deformation of conventional globe valves. In general, design of disc and seat is based on plunger principle. Disc is polished into plunger and connected with stem. Sealing is realized by two elastic sealing rings on plunger. Two elastic sealing rings are divided by a lantern ring and pressed tightly. Loading which applied on bonnet by nuts presses the sealing ring around plunger tightly. Elastic sealing rings are replaceable, and can be made from various materials. Plug globe valves are mainly used for turning on-off. Plug globe valves also can be used for regulating flow, for being equipped with special plunger or lantern rings.
