Consider a control valve action,the inlet air pressure is only 6 ksc but physi

Consider a control valve action,the inlet air pressure is only 6 ksc but
physically how it can be operate against 100 ksc line fluid pressure?

Question Posted / narasi23

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Consider a control valve action,the inlet air pressure is only 6 ksc but physically how it can be ..

Answer / ys

actally pressure=force/area.. here ctrl valve operates
against a very small area(the plug seat area).so the force
required for this also less. hence the ctrl valve acts
against high pressure

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Consider a control valve action,the inlet air pressure is only 6 ksc but physically how it can be ..

Answer / carl ellis

The reference to 6 ksc pressure means that the valve uses a
pneumatic actuator.

The ability of a pneumatic actuator to work against the line
pressure depends on the force that it can exert on the
valve's plug/cage/trim against the line pressure's force and
the bench setting of the spring.

A maximum of 6ksc of air inlet pressure can be exerted on
the total area of the actuator's diaphragm.

If the diaphragm area * air inlet pressure > plug area *
line pressure force + spring force, then the actuator will
move the valve plug. If not, the line pressure will move
the actuator.

A standard step in sizing a valve assembly with an actuator
is to check that the actuator can close against the maximum
line pressure and the spring setting at a given air supply
pressure. All vendors provide sizing charts for this purpose.

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