A globe valve is primarily used to regulate flow. Though generally not used, a globe valve can also be used for isolation where pressure drop in the line is not critical. The essential principle of globe valve operation is movement of disk towards or away from the seat. The annular space between the disk and seat ring is regulated thereby giving this valve good throttling characteristics.
Globe valves are available in the following designs :
- Regular Design (also sometimes referred to as Z-body design)
- Y body design
- Angle design
The Y pattern globe valve is a remedy for high pressure drop inherent in globe valves. The angle design results in a relatively straighter flow path thereby reducing pressure drop. They are best suited for high pressure and other severe services. They are often used as intermittent blowdown valves in steam service, in abrasive slurry or highly viscous services.
The Angle pattern globe valve is a modified version of globe valve with inlet and outlet at right angles. When fitted at a change in piping direction, this valve saves a bend and has the advantage of smaller pressure drop than a conventional globe valve.
Industry Codes and Standards
- API 6D - Specification for Pipeline valves
- API 598 - Valve Inspection and Testing
- API STD 624 - Type Testing of Rising Stem Valves equipped with Graphite Packing for Fugitive Emissions
- API 6FA - Fire Test for Valves
- BS 5152 - Cast Iron globe and globe stop and check valves
- BS 5352 - Cast and forged steel gate, globe,check and plug valves, screwed and socket welding ends (<= li="">
- BS 1873 - Steel globe valves and stop and check valves, flanged and butt welding ends
- API 623 - Steel Globe Valves-Flanged and Butt-welding Ends, Bolted Bonnets
- BS 6755 Pt. 1 - Specification for production pressure testing requirements.
- BS 6755 Pt. 2 - Specification for fire type-testing requirements.
- MSS SP 80 - Bronze globe valves
- MSS SP 61 - Pressure testing of steel valves
- MSS SP 25 - Standard marking system for valves, fittings, flanges & unions
- MSS SP 45 - Bypass and drain connections
Operators for Globe Valves
Most operators use the following guidelines to select the type of operators for Globe valves. When the effort to operate the lever exceeds 350 N geared operators are provided.
| Operator | Size | Rating |
|---|---|---|
| Handwheel | 10-inch and below | Class 150 |
| Handwheel | 8-inch and below | Class 300 |
| Handwheel | 4-inch and below | Class 600 |
| Handwheel | 3-inch and below | Class 900 |
| Handwheel | 2-inch and below | Class 1500 and 2500 |
| Gear Operator | 12-inch and above | Class 150 |
| Gear Operator | 10-inch and above | Class 300 |
| Gear Operator | 6-inch and above | Class 600 |
| Gear Operator | 4-inch and above | Class 900 |
| Gear Operator | 3-inch and above | Class 1500 and 2500 |
