Control Valves Unbalanced Trim and Balanced Trim
Update time: 21-05-27 Views: 11377
According to the structure of the valve trim, the Control Valve can be divided into unbalanced trim and balanced trim. Single seated Control Valves are typical unbalanced control valves, Cage Guided Control Valves are typical balanced control valves.
Unbalanced trim: There is no balance hole on the plug, the medium pressure differential acts on the effective area of the plug to generate a force equal to the product of the differential pressure across the plug and the plug’s area (F = PA). However, balanced plugs do not generate this same force because they equalize the pressure on both sides of the plug.
Balanced internal parts: There is a balanced plug has one or more holes drilled from top to bottom, allowing fluid pressure to equalize on both sides of the plug and the unbalanced force can be almost ignored. This helps minimize the forces acting on the plug which must be overcome by the actuator.
To sum up:
Unbalanced trim control valves are suitable for applications where the pressure difference is not large.
Balanced trim control valves are suitable for applications with large pressure differences.
