.png)
Top interview question for Calibration Engineer/ calibration technician
1. What are the different process variables?
- Flow
- Pressure
- Temperature
- Level
2. Define all the process Variable and state their unit of measurement
Flow: It is defined as volume per unit of time at specified temperature and pressure Conditions, is generally measured by positive-displacement or rate meters
measurement of height between minimum level points to maximum level point
is called level.
temperature.
The primary elements used for flow measurement are:
An orifice tab is welded on the orifice plate which extends outer of the line giving
an indication of the orifice plate
5. Why flow is measured in the square root?
The differential pressure measured has nonlinear relation with flow through the
pipeline. Differential pressure developed by a venturi, orifice plate, pitot tube,
or any other acceleration-based flow element is proportional to the square of the
flow rate. The square root extractor is used to convert the measured differential
pressure into the flow rate.
6. How do you calibrate a D. P. transmitter?
The following steps are to be taken which calibrating:
1, Adjust zero of the T's
2. Static pressure test: Give equal pressure on both sides of the transmitter. Zero
should not shift. If it is shifting carry out a static alignment
3. Vacuum test: Apply anequal vacuum to both the sides. The zero should not shift.
4 Calibration Procedure:
- Units: kg / hr., litter / min, gallon / min, m3 / hr., Nm3 / hr.
- Units: bar, Pascal, kg / cm2, Ib. / in2.
measurement of height between minimum level points to maximum level point
is called level.
- Units: Meters, mm, cm, percentage.
temperature.
- Units: Degree Centigrade, Degree Fahrenheit, Degree Kelvin, Degree Rankin,
The primary elements used for flow measurement are:
- Orifice Plate
- Venturi tube
- Pitot tube
- Annular
- Flow Nozzle
- Weir & Flumes
An orifice tab is welded on the orifice plate which extends outer of the line giving
an indication of the orifice plate
5. Why flow is measured in the square root?
The differential pressure measured has nonlinear relation with flow through the
pipeline. Differential pressure developed by a venturi, orifice plate, pitot tube,
or any other acceleration-based flow element is proportional to the square of the
flow rate. The square root extractor is used to convert the measured differential
pressure into the flow rate.
6. How do you calibrate a D. P. transmitter?
The following steps are to be taken which calibrating:
1, Adjust zero of the T's
2. Static pressure test: Give equal pressure on both sides of the transmitter. Zero
should not shift. If it is shifting carry out a static alignment
3. Vacuum test: Apply anequal vacuum to both the sides. The zero should not shift.
4 Calibration Procedure:
- Give 20 psi air or 24V DC supply to the transmitter
- Vent the LP. side to the atmosphere.
- Connect the output of the Instrument to a standard test gauge or Multimeter and adjust zero.
6. Adjust zero again if necessary.
7. How do you do zero checks on a D. P. transmitter?
Close one of the valves either H. P. or L.P. opens the equalizing valve. The O/P
should read zero.
8. Explain direct and indirect level measurement:
Direct level measurement:
Bob and tape: A bob weight and measuring tape provide the most simple and
the direct method of measuring liquid level
Sight glass: This consists of a graduated glass tube mounted on the side of the
vessel. As the level of the liquid in the vessel change, so does the level of the
liquid in the glass tube.
Indirect level measurement:
Pressure gauge: This is the simplest method, for pressure gauge, which is located at the zero level of the liquid in the vessel. Any rise in level causes an increase of
pressure which can be measured by a gauge.
Purge system: In this method, a pipeline is installed vertically with the level
open and zero. The other end of the tube is connected to a regulated air supply
and to a pressure gauge. To perform a level measurement, the air supply is
adjusted so that the pressure is slightly higher than the pressure due to the
height of the liquid. This is achieved by regulating the air pressure until bubbles
are seen in the cabin leaving the open end of the pipe.
Differential pressure meter: Connections are made at the vessel top and
bottom and to the two columns of the D.P. meter. The top connection is made to
the L.P. column of the transmitter and the bottom to H.P. column of the
transmitter. The difference in pressure in the vessel is balanced out since it is
fed to both the column of the meter. The difference in pressure deducted by the
meter will be due only to the changing, level of the liquid.
Displacer type level measurement: The level troll is one of the most common
instruments used to measure levels in closed tanks. This instrument works of
Archimedes principle. The displacer in immersed in the liquid due to which there
is a loss of weight depending on the specified gravity of the liquid. This displacer
hangs freely on a knife transmitted to the pneumatic or electronic counterpart
at the other end,
7. How do you do zero checks on a D. P. transmitter?
Close one of the valves either H. P. or L.P. opens the equalizing valve. The O/P
should read zero.
8. Explain direct and indirect level measurement:
Direct level measurement:
Bob and tape: A bob weight and measuring tape provide the most simple and
the direct method of measuring liquid level
Sight glass: This consists of a graduated glass tube mounted on the side of the
vessel. As the level of the liquid in the vessel change, so does the level of the
liquid in the glass tube.
Indirect level measurement:
Pressure gauge: This is the simplest method, for pressure gauge, which is located at the zero level of the liquid in the vessel. Any rise in level causes an increase of
pressure which can be measured by a gauge.
Purge system: In this method, a pipeline is installed vertically with the level
open and zero. The other end of the tube is connected to a regulated air supply
and to a pressure gauge. To perform a level measurement, the air supply is
adjusted so that the pressure is slightly higher than the pressure due to the
height of the liquid. This is achieved by regulating the air pressure until bubbles
are seen in the cabin leaving the open end of the pipe.
Differential pressure meter: Connections are made at the vessel top and
bottom and to the two columns of the D.P. meter. The top connection is made to
the L.P. column of the transmitter and the bottom to H.P. column of the
transmitter. The difference in pressure in the vessel is balanced out since it is
fed to both the column of the meter. The difference in pressure deducted by the
meter will be due only to the changing, level of the liquid.
Displacer type level measurement: The level troll is one of the most common
instruments used to measure levels in closed tanks. This instrument works of
Archimedes principle. The displacer in immersed in the liquid due to which there
is a loss of weight depending on the specified gravity of the liquid. This displacer
hangs freely on a knife transmitted to the pneumatic or electronic counterpart
at the other end,
9, How will you reverse the action of the level troll?
The reversing serves as a motion take-off arm from the torque tube. It is
provided with a slot on each side of the center so that the link can be connected
either for reverse or direct action. The output will be maximum.
10. What is Pt 100 mean?
The reversing serves as a motion take-off arm from the torque tube. It is
provided with a slot on each side of the center so that the link can be connected
either for reverse or direct action. The output will be maximum.
10. What is Pt 100 mean?
Pt100 means 100 OHMS at O degrees C for a platinum resistance bulb,
.png&description=Top interview question for Calibration Engineer/ calibration technician){kind=link}
0 Comments