On drum level, why we are using air to close Control valve?

Question Posted / govindam

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On drum level, why we are using air to close Control valve?..

Answer / carl_ellis

If the valve's actuator is Air-to-Close, what state does it
fail-safe state?

Check out the article, "How to destroy a boiler - Part 1"
at this link:
http://www.nationalboard.org/index.aspx?pageID=164&ID=238

and scroll down a couple pages to the section entitled "Low
Water Conditions".

The description will provide details that help you
understand what the fail-safe state due to the loss of a
control signal on a boiler feedwater control valve should
be.

Carl Ellis
Measure First

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On drum level, why we are using air to close Control valve?..

Answer / swastik d. u

If any problem in your
compressor, sudden stoppage
of air valve get opened. by
this we can maintain drum
level.

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On drum level, why we are using air to close Control valve?..

Answer / sanjay k

It means we used air failed to open condition to avoide
starvation in boiler.
At any condtion water must be kept in boler and in drum.
in case air fail the valve shold open and water goes in
boler.

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On drum level, why we are using air to close Control valve?..

Answer / govindam

i need answer

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