Q & A > Question Details
I am trying to find out the bore dia of restriction orifice plate to be placed in flushing oil line of 3/4" S80 going to a flow instrument handling Clarified oil. To calculate bore dia and thickness of restriction orifice plate, I need either pressure drop or flow across the plate which are not available. Flushing oil pressure is 14 kg/cm2 g and the flow instrument is operating at a pressure of 10.7 kg/cm2 g. How can I calculate bore dia with these details?
12/12/2015 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
To calculate an orifice diameter, I believe you need both a flow and a pressure drop. It's not clear though exactly why you are wanting to do this calculation. If this is an existing orifice you should be able to get the diameter from either plant records or from the orifice plate itself (they typically have the orifice bore stamped on the handle that protrudes out from the flanges.
If this is a new installation, your flow rate should be based on what ever flow rate is needed for your flushing service. Your DP can be based on the available system pressure (i.e. upstream pressure minus pressure of receiving system minus some allowance for line losses.
11/12/2015 A: Prakash Pimparkar, Environmental Consulting Services , prakash.pimparkar@yahoo.in
You need to consider hydraulic of the complete system. But if it is 10.7 you need at the outlet with inlet 14 ?.Then you have the pressure drop with you . Flow you can get from the the instrument data sheet.Instrument supplier should help you.