What is loop or pigtail in an impulse line?
Answers were Sorted based on User's Feedback
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.
Is This Answer Correct ? | 35 Yes | 12 No |
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
Is This Answer Correct ? | 26 Yes | 3 No |
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.
Is This Answer Correct ? | 18 Yes | 4 No |
Answer / habeeb
pigtail reduces velocity of steam,but pressure
same.temperature not effecting the instrument
Is This Answer Correct ? | 10 Yes | 2 No |
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.
Is This Answer Correct ? | 7 Yes | 0 No |
Answer / www.islamqa.com/en/
It used mainly in steam services to avoid direct contact
between sensor and high temperature steam.
Is This Answer Correct ? | 5 Yes | 0 No |
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).
Is This Answer Correct ? | 1 Yes | 1 No |
Answer / m.murali -inst. technoligist
TO AVOID THE SHOCK PRESSURE, IT WORKS AS SHOCK ABSORBER
Is This Answer Correct ? | 4 Yes | 6 No |
What types of Instrumentation Related Questions can an Interviewer ask in a Telephonic Interview ?
WHAT IS A SYMPTOM OF FAULT WITH THE SPAN OF AN INSTRUMENT? 1)ZERO-POINT AND 100% ARE CORRECT BUT NOT A MID-RANGE. 2)ZERO-POINT IS CORRECT ,BUT 1005 INPUT IS NOT GIVING 100% OUTPUT. 3)LINEARITY PRBS. 4)1005 O/p IS CORRECT BUT ZEO POINT IS WRONG.
Pls can anybody tell me how much memory plc's has?in byte or in Kb
suppose, after calibrating a transmitter we fixed it in a process line. At live zero condition the Tx shows 4.5 mA. what should we do to make the Tx show 4 mA? If we adjust zero, will it not affect the calibration?
how many parts of valve positioner?
What is an SCR?
how to trim the pressure transmitter ?
what is see back effect?
Regarding MOS (maintenance override switch), I want to know its function and its state ( 1 or 0 when not activated ). An example will be very helpful..thank you.
where proximity sensor installed on tank in loading arm application
how to connect 3 wire 4-20 mA transmitter in Plc system PLC system and how explain how the measuring data communicate with plc system.
Control valve question what is the meaning of cauge.?what is the use of cauge?