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Type: Globe Valve.
Materials: ASTM A216 WCB.
ENDS: Butt Weld.
Class: 900LB
Size: 5 Inch (DN 125).
Feature
Globe valve is a type of valve with spherical body shapeenclosing the valve seat and a movable valve disc.
It is available in 2” to 48” size with pressure ratings of 150#, 300#, 600#, 800#, 900#, 1500#, and 2500#. The end connections for globe valve also come in varieties which are Raised Faced Flanged, Socket Weld, NPT/Thread, and Butt Weld.
Globe valves are commonly used as an on or off valve, but they also may be used for throttling systems.
The gradual change in spacing between the disk and seat ring gives the globe valve good throttling ability.
Operation
Globe valves have a disk which can completely open or completely close the flow path.
The annular space between the disc and seat ring gradually changes to allow fluid flow through the valve.
For low temperature applications, globe valves are ordinarily installed so that pressure is under the disc. This promotes easy operation, helps protect the packing, and eliminates a certain amount of erosive action to the seat and disc faces.
For high temperature steam service, globe valves are installed so that pressure is above the disc. Otherwise, the stem will contract upon cooling and tend to lift the disc off the seat.
Types of Globe Valves
Tee Pattern globe valves have the lowest coefficient of flow and higher pressure drop. They are used in severe throttling services, such as in bypass lines around a control valve. Tee-pattern globe valves may also be used in applications where pressure drop is not a concern and throttling is required. Refer to Fig. C.
Wye Pattern globe valves, among globe valves, offer the least resistance to flow. They can be cracked open for long periods without severe erosion. They are extensively used for throttling during seasonal or startup operations. They can be rod through to remove debris when used in drain lines that are normally closed. Refer to Fig. A.
Angle Pattern globe valves turns the flow direction by 90 degrees without the use of an elbow and one extra weld. They have a slightly lower coefficient of flow than wye-pattern globe valves. They are used in applications that have periods of pulsating flow because of their capability to handle the slugging effect of this type of flow. Refer to Fig. B.
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