Answer / k. thirunathan ntpc ramagund

1.PIGTAIL IS USED ONLY IN STEAM LINE WHICH HELPS TO CONVERT
STEAM VAPOUR PHASE IN TO LIQUID WATER PHASE
2. AVIOD HIGH TEMPERATURE DIRECTLY CONTACT
IN INSTRUMENT LIKE PRESSURE GAUGES,PRESSURE
TRANSMITTERS..etc.
3.FINALLY IT REDUCES HIGH PRESSURE INTO LOW PRESSURE AND
AVIOD VIBRATION IN IMPULSE LINES.

Answer / solomon

pigtail is also called syphon.It is used to reduce
temperature of fluid like steam before enter in to the
Pressure gauge or Presssure Transmitter for measurement

Answer / haridass_drm

My friend, Mr. K. Thirunathan Ntpc Ramagund, all your
points are correct, except

3.FINALLY IT REDUCES HIGH PRESSURE INTO LOW PRESSURE AND
AVIOD VIBRATION IN IMPULSE LINES.

In this point, avoiding vibration is ok, but how the high
pressure will get reduce to low pressure? If like, how can
we use that pigtail for high range pressure
gauge/transmitter?

According to me, this pigtail will be used to avoid the
sudden pressure impact on the gauge/transmitter, created in
the process where it fixed. Because the boiler/vessel/steam
line will be high pressurized, so there is the chances for
sudden variation, the pigtail will safe the instruments if
it used.

Answer / habeeb

pigtail reduces velocity of steam,but pressure
same.temperature not effecting the instrument

Answer / sreekanth

Friends....Pigtail is used only for protection of
instrument from temperature.

For pressure Damping we will use Pulsation Dampners.

Due to the loop, condensate is formed in the pigtail and
some part of fluid cannot be drained and remain in the
pigtail which will prevent the instrument all the time from
temperature from direct contact of the fluid.

Answer / www.islamqa.com/en/

It used mainly in steam services to avoid direct contact
between sensor and high temperature steam.

Answer / suresh m (fcri)

Loop/Pigtail helps provide for tube expansion due to
temperature changes. If tube is straight and directly
inserts into the pressure transmitter (which is also
rigidly fixed to a support), there will be streses in tube
due to expansion/contractions.

In steam applications, impulse tubes are to drain
condensate back into process line and transmitter is fixed
generally above process line. The same with gas
applications. For liquid applications, the impulse tube
slopes to eliminate gas formation inside which escapes back
to process line.
In both cases, the pigtail/loop will therefore have to be
appropriately directed (either upward or downward
respectively, even as slope is maintained for impulse
lines).

Answer / m.murali -inst. technoligist

TO AVOID THE SHOCK PRESSURE, IT WORKS AS SHOCK ABSORBER

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