Friday, November 24, 2017

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Globe Valves - Double-Ported Valve Bodies

  • Dynamic force on plug tends to be balanced as flow tends to open one port and close the other.
  • Reduced dynamic forces acting on plug might permit choosing a smaller actuator than would be necessary for a single-ported valve body with similar capacity.
  • Bodies are usually furnished only in the larger sizes—4-inch or larger.
  • Bodies normally have higher capacity than single-ported valves of the same line size.
  • Many double-ported bodies reverse, so the valve plug can be installed as either push-down-to-open or push-down-to-close (figure 3-7).
  • Metal-to-metal seating usually provides only Class II shutoff capability, although Class III capability is also possible.
  • Port-guided valve plugs are often used for on-off or low-pressure throttling service. Top-and-bottom-guided valve plugs furnish stable operation for severe service conditions.

Figure 3-7. Reverse-Acting Double-Ported Globe-Style Valve Body

Figure 3-7. Reverse-Acting Double-Ported Globe-Style Valve Body


The control valve body shown in figure 3-7 is assembled for push-down-to-open valve plug action. The valve plug is essentially balanced and a relatively small amount of actuator force is required to operate the valve. Double ported designs are typically used in refineries on highly viscous fluids or where there is a concern about dirt, contaminants, or process deposits on the trim.

Go to the next page, Valve and Actuator Types - Control Valves - Globe Valves - Three-Way Valve Bodies

Go back to the previous page, Valve and Actuator Types - Control Valves - Globe Valves - Port-Guided Single-Port Valve Bodies

Go to the Control Valve Handbook - Table of Contents page



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