Globe Valve Specifications

These specifications are recommended for globe valves in the following typical services  

100-pound air, 50-pound caustic, 15-pound condensate, 50-pound fuel, 150-pound hydrocarbon, and 40-pound exhaust. The ratings are 230 psi at 100°F, 150 psi at 500°F and 100 psi at 750°F (maximum). 

For 1-1/2-inch and smaller globe valves, specify 600-pound SWP forged carbon-steel, screwed, inside screw stem, union bonnet, 11 to 13% chrome stainless-steel trim. For air and condensate service, use 250-pound SWP brass, screwed, rising stem, union-bonnet valves. 

For 2-inch and larger globe valves, specify 150-pound ANSI standard cast carbon-steel, flanged, OS Y, 1/16-inch raised face, 11 to 13% chrome stainless-steel trim. For condensate service use gate valves for 2-inch and larger sizes. Also, use gate valves for aU sizes above the 6-inch size. 

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Valve Application Technology Functional requirements and the properties of the controlled fluid determine which valve and actuator types are best for a specific apphcation. If demands are modest and no unique valve features are required, the valve-design style selection may be determined solely by cost. If so, general-purpose globe or angle valves provide exceptional value, especially in sizes less than 3-inch NFS and hence are very popular. Beyond type selection, there are many other valve specifications that must be determined properly in order to ultimately yield-improved process control. 

Specification for Flanged Steel Globe Valves— Bellows 8 1997... 

The control valve bypass valve should be a globe valve of the same size as the control valve and should meet line specifications. 

All three types of valves described above are on-off type devices (binary devices). A basic requirement in the design of these valves is that they offer minimum resistance to flow when open. For many types of calculations it is often justifiable to neglect pressure losses through such devices. But such a simplification cannot be applied to flow control valves. With these devices the control of flow is accomplished either by a constriction or by a diversion. In either case an additional resistance to the flow is introduced. Globe, angle, cross, and needle valves are typical devices of this type. Specific pressure drop correlations should be developed for such devices and used whenever possible. One such correlation used by Stoner (S5) takes the form... 

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