how is a displacer type level transmitter calibrated.explain the method?

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how is a displacer type level transmitter calibrated.explain the method?..

Answer / a.moin

A displacer type level is most commonly level application
used for the closed vessel as well as interface level where
the two process liquid having diffrent specific gravity.

Its works on the arthmedics principle or the loaw of
buoncy, the law say the weight of the substance immerse in
the liquid is equal to the amount of liquid displaced by
the body.

Now as per the question the way to calibrate the displacer
level first we have to isolate the level troll chenber from
its process by isolating the root valves,
then drain the liquid presence inthe chamber, connect the
PVC transparent tube at the bottom of the cahmber and then
start filling the water in the tube.

For zeroing
fill up the water into chember and adjust the zero check
this function two or three times....

compensate the S. G of diff liquids Prcoess S.G= 0.7 and
water S.G= 1.0
to calibrate the transmitter for span 0.7/1.0 *100= 70%
fill the water upto 70% adjust the span
For dry calibration of displacer you should knwo these
details below
Displcer weight: 2400 grms (2.4Kg)
volume of Displacer: 1620.84 by ^r2h..
displacer diameter: 7.620 centimeter
length of displacer: 35.56 centimeter
Note: the limitation of displacer cannot be exceed more
than 72 inches....

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how is a displacer type level transmitter calibrated.explain the method?..

Answer / haridass kwt

To calibrate the displacer type LTs by fixed in the w/bench,

First remove the head, clean displacer and chamber and
assemble,

fix the calibration setup (drain isolation, clear tube and
marked scale),

Calculate 100% position of fluid filling, by the Sp.
gravity of the fluid where the LT being used. (Ex: If sp.gr
is 0.8, then the 80% of the displacer height to be marked
in chamber due to the water used for calibration), and mark
every 25% in chamber ouside for reference.

Fill the water and check the transmitter/board/sensor
response approximately.

Fill the water till the displacer touches. and chk 0% and
adjust to 4mA.

Fill the water till 100% to check span and adjust 20mA.

(If the LT s not responding, replace LVDT/board and chk)

Repeat zero and span check 4-5 times and the chk every 25 %
rising and falling.

If ok, the prepare the calibration report and tag it.