PDA

View Full Version : Kiril - Need help - tickle your brains a little


Dirt Boy
08-18-2011, 10:49 AM
Not exactly irrigation related, but similar.

Looking for equation or information on:
What is the effect of a restriction on flow?

If you have a 1" pipe (nom. size, your choice of mtl.), certain pressure, etc. and you have a fitting that has a slightly smaller ID, what will the effect be on flow (volume) after that fitting/restriction?

Reason I am asking, and you can dice me if you wish, is that I am working on a project (not irrigation related .... medical related ..... think hypodermic needles) so it's super small volume and very minute, if any, flow difference.

Not sure where to look on the web, but figured some of you may have an idea or two.

Thanks a bunch!

Wet_Boots
08-18-2011, 11:02 AM
Pipe fittings have equivalents in feet of straight pipe, for the purpose of calculating losses.

Dirt Boy
08-18-2011, 11:59 AM
Thanks Boots,
After a bit of research, I am finding out this is way over my head.

Things like what kind of restriction, is it a sharp edge, rounded constriction, etc. etc.

Like I mentioned, this is for super small "pipe". Thankfully we don't have to be super concerned with this in irrigation, most of the time .... it would make my head hurt :dizzy:

Wet_Boots
08-18-2011, 12:36 PM
If you find a table of fitting equivalents, you see the conversions change as the pipe diameter changes. I don't believe I have ever seen any calculations for ultra-small tubing hydraulics. The closest the sprinkler world got to it was the distance limit between Toro "pin-type" hydraulic valves and the controller (no limit exists for normally-open hydraulic valves, but the simpler "pin-type" arrangement required the tubing to pass enough water to act like a bleed screw)

Kiril
08-18-2011, 01:24 PM
Not exactly irrigation related, but similar.

Looking for equation or information on:
What is the effect of a restriction on flow?

If you have a 1" pipe (nom. size, your choice of mtl.), certain pressure, etc. and you have a fitting that has a slightly smaller ID, what will the effect be on flow (volume) after that fitting/restriction?

Reason I am asking, and you can dice me if you wish, is that I am working on a project (not irrigation related .... medical related ..... think hypodermic needles) so it's super small volume and very minute, if any, flow difference.

Not sure where to look on the web, but figured some of you may have an idea or two.

Thanks a bunch!

There are a ton of factors that can come into play in this type of scenario give the size of the "pipe" you are talking about and you are likely not talking about water. To be perfectly honest, this is far too complex a problem to easily explain nor do I believe it can be solved with a single equation.

Kiril
08-18-2011, 01:34 PM
If you don't mind me asking, what are you doing here? My guess is some type of hydroponics, CT or aquarium dosing?

Dirt Boy
08-18-2011, 02:05 PM
If you don't mind me asking, what are you doing here? My guess is some type of hydroponics, CT or aquarium dosing?

None of the above, has nothing really to do with irrigation of any type.
It is a question involving the manufacture of a medical product i.e. hypodermic needle tubing.

And you are very right, after doing more digging, there are absolutely a ton of factors to consider ..... quickly going right over the top of my head.

Sorry to bother you all, at first blush, I thought it might be fairly simple.:hammerhead: