The Crane Technical Paper No. 410 " 1

[casflo]

The Crane Technical Paper No. 410 "Flow of Fluids Through Valves, Fittings and Pipe" is as a Bible for many engineers dealing with the flow of fluids in different industry fields.
Related with this paper, I want to expose the following subject:
During many editions, the expansión factor Y to calculate the restriction orifice plates (ROs) for steam and gases, was defined for P´2/P´1 equal or greater than 0.4 and even less. See for example the page A-21 in 1988 edition. But in the 2010 edition, in the page A-22, the values of P´2/P´1 are only equal or greater than 0.8, because now the paper considers the RO plates mainly as measuring devices.
My question is if any one knows which must be now the value of Y to calculate RO plates as restriction orifices when the relation between the downstream pressure P´2 to the upstream pressure P´1 is less than 0.8

 

[hacksaw]

Are you dealing with a flow restriction device? or are you dealing with critical flow measurement?

 

[casflo]

I dealing with a flow restriction device

 

[Latexman]

2018 Version:

Good Luck,
Latexman

 

[monkeydog]

My 25th Edition (1991) has the same values as Latexman. Scaled slightly different, but same values.

 

[georgeverghese]

Would suspect the page @latexman has posted is applicable to contoured nozzles and venturi devices. While the OP requests for Y values for restriction orifices where the RO thickness ratio t/D is less than some critical value when r < 0.8 or so.

Flow measurement literature tells us that flow through thin plate restriction orifices continues to increase when r < rc, while flow reaches a critical max at rc for venturis and contoured flow nozzles.

You may need to search for this info for Y in some flow measurement handbook, or else repost this request for info in the "measurement and controls instrumentation" forum. Else select a thick plate RO for flow restriction service.

 

[Latexman]

No, the graphs are for orifices and flow nozzles.

Good Luck,
Latexman

 

[georgeverghese]

@latexman, okay, didnt see the graph at the top for orifices at first glance.

In this case, these graphs should be valid for thick or thin plate orifices in restriction service down to the lower limit of r = 0.4 shown in the graph for square edge orifices.

The graph at top right gives values for rc for nozzles and venturis only; not stated here what rc is for restriction orifices.

 

[casflo]

Thank you very much all, specially to Latexman. I have not this edition of the Crane. It seems that about the restriction orifices, the Crane came back to the content of the editions from before 2009.

 

[Iomcube]

casflo highly appreciated this information. Version 2009 I had been following always treats RO as measuring device & I for restriction orifices I have to look elsewhere