Restriction Orifice and cavitation

The number of plates depends on the total pressure drop.

It is not necessary to have big distances between plates if the holes are not centric and the flow has a meander path. The minimal distance has to be about dhole/2. Only in centric holes the following on has to be far enough to allow the flow to came at a uniform velocity pattern if not the effect of it is not total.

This is a solution I used in hydraulic circuits with pressure drops up to 350 bar. The reason was mainly the noise generated by cavitation which had to be avoided.

Thank you for answer. I don't need a large pressure drop, but the pressure after the orifice should be 2,5 bara. and the desired pressure drop is 6,5 bar. I need a constant flow rate of 590 m³/hr (that is controlled by a control valve upstream) in a 8" pipe.

The pressure in the main flow had to be reduced so it can be added to a parallel flow with 6,5 bar lower pressure downstream the orifice.

Another option might be perforated plates stacked off center from each other. This has been used for pressure reduction for stteam systems.

I am "CoronaCameraMan" ...

As "Nickname" said how great is the pressure drop ?

A globe valve is meant for throttling flow.

Are you working with variable pressure that the flow will change for a fixed opening ?

If so use a temperature-pressure compensated flow control valve, they are frequently used in hydraulics, there are similar valves used for steam, etc.

Couldn't you use a thicker plate with a bell shaped opening (think trumpet) to reduce the dv/dt of the fluid?

Gordie.

Use two plates in which the holes are offset from each other. The meander can make up the restriction of the third plate.