calculating an orrifice for a given flow/pressure

[Anguz]

i need to be able to input a pressure, and a required flow, to calculate a flow in water
excel, or online, or at a push a formula

anyone got experience in making basically shim to put in a pipe line ??? guess any chamfer on the hole can make quite a lot of difference ?

 

[8ob]

Not that different to the one we use for hydraulics, it may be what you are looking for https://www.tlv.com/global/UK/calculator/water-pipe-sizing-pressure-loss.html

Bob

 

[RonA]

Used to use BS1042 for calculating orifice plates when I worked but apparently this has been withdrawn in favour of BS ISO TR 15377:1998.
RonA

 

[Anguz]

Almost but not quite.... basically we have a tank to drain, and are only alowed to discharge to waste at a max rate
The orifice will be into effectively an open channel

 

[thinfourth]

if you go here

https://www.masterflo.com/sizing/

They will send you a link for their sizing software which will let you calculate the CV needed

from the CV you can then calculate the size of an orifice you will need

but bare in mind your head will reduce as the tank drains so you won't maintain the same flow throughout

 

[daleyd]

As above, if you want proper constant flow you would need some sort of feedback and closed loop control, but if you only want to ensure you can’t go over a certain flow then an orifice plate would be sufficient.

 

[gordon stephenson]

As you mentioned, a chamfer or radius on the up-stream side can make a big difference,

 

[RonA]

Almost but not quite.... basically we have a tank to drain, and are only alowed to discharge to waste at a max rate
The orifice will be into effectively an open channel

If its an open channel you can insert a flate plate with a triangular notch & use the calculations for flow of a weir.
http://irrigation.wsu.edu/Content/C...urements/90-Degree-Triangular-Notch-Weirs.php
The orifice plates we used in pipe flanges were all square edged with D & D/2 tappings.
Ron