Thursday, October 26, 2017

When to Use a Globe Valve for Fluid Process Control

cast iron globe valves
Cast iron globe valves are utilized extensively in steam,
HVAC, and other commercial and industrial applications
Image courtesy of Crane Co.
Industrial process control often involves the regulation of fluid flow. There are almost uncountable types and variants of flow control valves, each with a particular set of attributes that can make it the advantageous choice an application.

When the process calls for controlling flow over a range of possible values, known as throttling, a globe valve may be a good candidate for the application.

Globe valves are characterized by the change in direction of fluid flow as it passes through the valve and around the plug positioned in an opening through which fluid must pass. The plug is connected to a stem extending to the exterior of the valve body through the bonnet. Movement of the stem will reposition the plug in relation to the opening, providing a successively larger or smaller opening area through which fluid can pass.

Globe valves are available in tee, angle, and wye configurations, as well as an enormous range of special configurations to suit specific applications.
simplified globe valve diagram
Simplified globe valve diagram
Image courtesy Wikipedia


What are some potential advantages of globe valves?
  • Good throttling and shutoff capability
  • Comparatively easy maintenance
  • Comparatively short travel of plug from open to closed position
  • Seats can usually be resurfaced when worn
What are some limiting factors for globe valves?
  • Higher valve pressure drop than some other designs
  • No straight through fluid path
  • Potentially higher actuator torque requirements than other valve types
  • Seal area is unprotected from exposure to process fluid flow
When flow throttling capability is the overriding concern for an application, a globe valve is a good candidate for consideration. Share your flow control challenges with valve and automation specialists. Combining your process knowledge and experience with their product application expertise will produce effective solutions.