Furnace draft transmitter range is -50 to +50 mmwc. why the
impulse line connected in hp side?
Answer Posted / carl_ellis
A draft range measurement is typically a gauge pressure
measurement, referenced to atmosphere.
Draft range is very, very low pressure, so DP transmitters
are typically used because they're readily available in
a 'draft' range with the large diaphragms necessary for low
pressure measurements.
The high side is connected to the process with an impulse
tube. The low side is exposed to atmospheric pressure.
Good practice puts a filter, like a scintered pneumatics
filter on the low side, so that dirt doesn't fill the low
side cavity and air movement (wind, passing vehicles) is
buffered and damped to prevent the forces of air movement
on the low side from affecting the draft measurement.
If the impulse line were connected to the low side, the DP
would be negative, a DP subtracts the low side pressure
from the high side pressure (atmosphere minus some positive
pressure = negative pressure). Convention says that draft
range is positive so the impulse connection is to the high
side, to get a positive value.
Tell 'em Carl sent you.
| Is This Answer Correct ? | 12 Yes | 1 No |
Post New Answer View All Answers
what is gas metering system? gas chromatograph? and gas compressors?
how u choose thermowell lenght n pnumatic C/v size?
what is moisture probe? What are there types? What is there working principle and how they works? guys this is one of technical question I had ask in interview. If you know its answer please let me know. The interviewers were more interested in microwave moisture probe, so if you find its any link please just forward me on my mail id.avinash1200@gmail.com Thanks in advance.
Full form of KKS when use DCS.
Explain an adaptive / self-tuning controller’s major draw card.
What is the use of temprature compensation?
How many are the types of instrument cables in terms of No. of pair.
why we use 3 wire rtd direct wiring for temperature measurement instead of temperature transmitter like bearing temperature
How is flow measured in square root?
Make a ladder diagram on LSL valve will close, on PSL valve will open and start the motor
what is the electrical operation procedure for switching on 27.6MVA electric furnace.
What is force balance principle? State some of its’ advantages.
Whether the DI, DOs shields can be connected with Analog Input Shield Earthpit?
Instrumentation symbols interpration, P& ID, Logic diagram analysis, Electrical drawing analysis.
please send me the inteview questions in IOCL