Steam Flow measurement by differetinal pressure


Thread Starter

puya g-afshar

i want to measure the liquid (sugar juice) and steam flow rate in asugar factory,and all i have is some differential pressure transmitters. i have not the relation between delta P and flow
i will be thankful if you could help me
it is of my geart pleasure if you send the answer through my email

A.K.Hait, Instrumentation Engineer

For steam flow measurement you can use Concentric square edge orifice plate. Steps to be taken are:
- gather the process data regarding flow, pressure, temperature, pipe line I.D., pipeline material etc.
- Give the data to a orifice plate manufacturer who will size the orifice plate to tell you how much differential pressure willbe produced.
- Calibrate the flowmeter with the selected diff. pressure.
- Install the orifice plate. Connect the impulse lines from flange tappings to the meter.
- Don't forget to add two condensate pots and keep them in the same vertical plane.
- Connect the transmiiter in the control room computer/DCS.
- Do the square root extraction either in the transmitter or in the computer.
- Get the reading.

For sugar juice you need to know the viscosity of the liquid. If it is clean liquid with viscosity around 1 centi poise (CP) then you can use the concentric orifice plate again. The steps as indicated above to be taken to get the reading.

You need to take the square root of the D/P percentage, and multiply by 10 to calculate volumetric flowrate. EG1 - 25 % D/P is therefor equal to 50 % flow ( 5 x 10 )
EG2 - 50 % D/P is 70.71 % flow ( 7.071 x 10 )

In my opinion, a Magnetic flowmeter is more suitable for sugar juice as it does not restrict the line, and you may want to consider a Vortex flowmeter for the steam flow. Also, with steam flow, one should correct for temperature & pressure fluctuations. Contact Yokogawa via e-mail at [email protected]
We are having some troubles in steam measurement by using dpcells. The problem is the water in the condensate pot get off. We want to check if we are using the appropriate "good practices" to connect the dpcell sensor to the steam pipe.

My email is [email protected]

Thanks a lot for your answer, in advance