# question about compressor discharge line size.



## ltair (Oct 14, 2013)

I undertand boyles law and am trying to relate it as simple without too many variables but can't seem to find an answer anywhere.
Simply put. What is the effect on changing the diameter of the discharge line larger or smaller in relation to time it takes to fill the tank and implications on water and psi if any. 
Want to keep it simple, single cylinder , oiless air pump to tank. I realize implications of modifications and that's not part of what I'm asking, but feel free. 
If it can be answered regardless to relation of inlet and discharge ports, in simple theory, awesome, if not then please help with the implications of bottlneck or loss of suction but I believe them of little significance here as we are talking about going from 3/8 to 1/4 or 1/2. What does larger or smaller do to delivery to the tank? In theory as to eliminate all the other variables.


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## ltair (Oct 14, 2013)

Really? Does nobody have an idea? Or is it one of those questions that are just too dumb to answer?


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## tractornut (Sep 17, 2010)

I'm sure that there is an answer for your question I just don't have it there are a few really knowledgeable folks on here who may have the answer for you just give it some time and I'm sure they will be along with an answer


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## kanoa50 (Oct 6, 2013)

I'm not super knowledgeable but pretty sure Bernoulli's principle is at work. There's a lower pressure and higher velocity through the smaller line.. and opposite for a larger one. 

I don't think you will notice a difference between these line sizes unless the cfm output of the pump is great enough to feel a significant back pressure from the smaller hose (initially when the pressure differential between the pump and the tank is greatest). 

Assuming the pump's output is large enough for that, your pump could work a bit harder and fill the tank a bit slower, maybe only for a percentage of the filling.


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## shanonmethod (Nov 13, 2013)

kanoa50 said:


> I'm not super knowledgeable but pretty sure Bernoulli's principle is at work. There's a lower pressure and higher velocity through the smaller line.. and opposite for a larger one.
> 
> I don't think you will notice a difference between these line sizes unless the cfm output of the pump is great enough to feel a significant back pressure from the smaller hose (initially when the pressure differential between the pump and the tank is greatest).
> 
> Assuming the pump's output is large enough for that, your pump could work a bit harder and fill the tank a bit slower, maybe only for a percentage of the filling.


Kanoa I think the pressure occurs when work on low to high.The compressor machine pump does not consume right air pressure way between low to high while working hours.


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