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Why Use Double Acting Valves?

03/12/2017 5:55 AM

why we use double acting valves instead of single acting? please also give explanation.

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#1

Re: Why we use double acting valves?

03/12/2017 9:00 AM

This is a larger topic than can be handled in brief forum posts; it could take several pages. Various mfrs of pneumatic valves might have good literature. (Parker, Festo, ASCO to name some examples; no endorsements intended.)

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#9
In reply to #1

Re: Why we use double acting valves?

03/15/2017 12:29 AM

will you provide a link for learning.

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#10
In reply to #9

Re: Why we use double acting valves?

03/15/2017 4:52 AM

A 10-min chat with the Supervisor in the facility's Instrument Workshop is all that is needed. Time for a walk, rather than being glued to the computer all day, perhaps?

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#2

Re: Why Use Double Acting Valves?

03/12/2017 8:36 PM
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#8
In reply to #2

Re: Why Use Double Acting Valves?

03/13/2017 11:26 AM

The reason for that is on a positionable valve, the air source that is acting as the return spring is on a regulator, so you have a variable spring rate available this way. Allows a bit more fine tuning without replacing return springs. In 25 years, I've run into one customer that uses this arrangement on all their process skids. None of our other customers do.

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#3

Re: Why Use Double Acting Valves?

03/13/2017 5:16 AM

Usually because they're cheaper

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#5
In reply to #3

Re: Why Use Double Acting Valves?

03/13/2017 8:19 AM

being smaller, they don't need the extra force to compress the spring, if you don't need them to fail closed/open on loss of air

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#6
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Re: Why Use Double Acting Valves?

03/13/2017 9:33 AM

That's right

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#4

Re: Why Use Double Acting Valves?

03/13/2017 5:19 AM

If the actuator motoring utility supply fails for any reason:

  • A double-acting valve will stay put in its last position.
  • A single-acting valve will work to the position dictated by the configuration of the spring inside the actuator.

The reasoning for doing either of the above is determined by the Process Engineer during the design phase of the plant. It will be found in a document called "Process Description", "Plant operating mode", or similar. Why <...we...> do anything is a mystery to the forum as <...we...> is undefined and the actions of <...we...> are not known and cannot be seen from here.

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#7

Re: Why Use Double Acting Valves?

03/13/2017 10:46 AM

Because of requirement of fail condition of air supply that is site specific.

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