flow equation

Some questions:

• What is the fluid?
• At what temperature and pressure?
• What is the diameter of the pipeline (assuming circular cross-section)?
• How many diameters of straight line are there upstream and downstream?
• How come a separate orifice and flowmeter has been designed instead of buying an off-the-shelf, ready calibrated, package?

Check out high pressure spray painting equipment they have many differnet size tips with rate of flows and metering.

Please refer British Standard 1042 or

ANSI/API-2530

Accurate flow measurement to zero flow is impossible. You have defined a turndown (TD) of infinity. Set a low side flow that is reasonable. An orifice with dP measurement can handle TD of say 5 (a guess) so your minimum should be about 20 tph. Other FMs have more TD.

how to calculation orifice plate bore dia. if my flow range is 0 to 100t/hr and instrument range is 0 to 2500mmH2O

If you are not familiar with hydraulics,it is easiest to use an orifice calculator available on various web sites.

simply put diaof orifce d = f*{Q / h60.5}^0.5

where d - in mm

Q -flow rate in cubic metres/hr

h- differential head across the orifice - m

f is a throttling coefficcient depending on ratio of area of orifice to the area of pipe psteam of orifice.

If you can allow full 2500 mm of water as the max range for the differential ,you may as well try the following :

Dia of upsteam pipe - 150 mm

Dia of orifice - 45 mm

max differential 2500 mm of H2O for 100 ton/hr flow rate.Read more on flow coefficient to understand orifice working.

Chuck

Buy yourself a copy of Crane's Technical Paper 410, it will solve your problems. As stated by others, we need some fluid properties to give you an answer.

Surprised to learn that Technical Paper is still available. It is my bible for flow calcucations. I have an old edition. Have there been any recent updates?

Mine is copyrighted 1988 and I only got it about 4 years ago. It still looks the same, same old lab set up pictures and everything.

Hello,

You can also use ISO 5167 part 1/2 the equations used are in mass units and in SI system

Regards

Jose