Orifice Plate Sizing Criteria

You will have a lesser probability to find experts/experienced on your field here if you are looking for such. But, the fact is your problem can be solve not by experts alone. Most people here are good thinkers... with thoughts basing from sound engineering, I should say.

Orifice is just an orifice by the way, it measures the flow rate by means of ratio of two standard size cross sections & conditions(properties, like P & T) at that point.

BUT, in order to have their good thoughts burnin like fire, you have to provide a concrete/detailed problem description, show some process diagrams, figures, pictures that will help them absorbed the totality of your problem so that they can help you, with their outstanding solutions, I should say

A cheque would help too. Stinky Pete only deals in cash, reputedly.

Read something about pure substance p-v curve. I bet, you could settle your problem solving for qualtiy x-(% @8barg &340 deg C), then given the mass flow rate, you could estimate how much steam was converted to liquid phase and what remain as dry, then you could decide the frequency of your draining.

If orifice is equipped with differential pressure transmitter, consider the maximum pressure tolerable for the DP transmitter transducers, you should not be installing orifice, that will destroy it. Differential pressure for that orifice should be tolerable to DP transmitter.

Design flow rates are given 16.5 kg/s just look at steam tables at (pressure, temp) for specific volume, you can derive the flow rate then.

What else?

Hi Noudge79, Unfortunately i am out of my office, otherwise i would have posted the PID. The design flow rate given are for the process, not for the drain conditions. The drain will be open when upstream stop valve for the main line is closed. I think there no point in explaining without a diagram. I will post a diagram when will get back to office. Thanks

See if you can get your hands on a copy of "Design of Fluid Systems: Hook-Ups" by Spirax Sarco. "Design of Fluid Systems: Steam Utilization" will be helpful to you as well.

Thanks for all