Globe Valves
Fisher globe valves offer broad process versatility, solve your application needs from big to small, hot to cold, general to severe.
Fisher globe valves offer broad process versatility, solve your application needs from big to small, hot to cold, general to severe.
A throttling globe valve uses a linear motion to move a closure member into and out of a seating surface. They have a body distinguished by a globular-shaped cavity around the port region and are designed to regulate process flow when used in conjunction with an actuator assembly. Many single-seated valve bodies use cage or retainer-style construction to retain the seat-ring, provide valve plug guiding, and provide a means for establishing particular valve flow characteristics. Cage or retainer-style single-seated valve bodies can also be easily modified by change of trim parts to change the flow characteristic or provide reduced-capacity flow, noise attenuation, or reduction or elimination of cavitation.
Globe valves are available in a variety of sizes (NPS 1/2 thru 36) and provide users with high performance and reliability. They can help solve an array of application needs from big to small, hot to cold, general to severe.
Bonnets are available in different styles to accommodate different application temperatures. This primarily includes standard bonnets and optional extension bonnets, which may be used to protect packing materials when the valve is used in extremely hot or cold applications.
There are also special packing configurations for applications that require the packing system to maintain fugitive emission concentrations below environmental standards.
Some of the most typical applications of globe valves include cooling water systems, fuel oil systems, feedwater or chemical feed systems, boiler and main steam vents and drains, and turbine lube oil systems.
Globe valves can be fitted with balanced or unbalanced plug designs. Balanced ports allow for equal process pressure above and below the plug, and typical flow direction is down through the seat ring. An unbalanced plug is solid, with no through holes, and typical flow direction is up through the seat ring.
There are also several ways to guide the plug in a globe valve, most commonly cage-guided and post-guided. Cage-guided assemblies can use both balanced and unbalanced valve plug designs. This guiding method uses the outside diameter of the plug in contact with the inside diameter of the cage and provides very good pug stability and alignment, but requires very tight tolerances between the plug and the cage. Post-guided assemblies replace the cage with a component called a seat ring retainer. The seat ring retainer contains a guide bushing that provides guiding for a post on the plug. This style allows for an open flow path around the plug which makes post-guided trims better for us with viscous and dirty fluids.
A choice of trims with different flow characteristics allow globe valves to be linear, equal percentage, or quick opening so they can meet capacity demands from 0.001 Cv up to 12,000 Cv.
Specialty trims are also available that have been designed to prevent noise and cavitation issues in both clean and dirty applications.
