stupid plumbing question

[CHOMPERS]

...into two 3/4" pipes, unrestricted, the pump theoretically would still be pumping through one 1.5" pipe. Even if you split that 1.5" four ways as long as all the diameters added up to 1.5", or close to it.

Actually that's a common mistake. But don't feel bad, you are half right. It will take four 3/4" pipes to equal one 1.5" pipe. You have to use the cross sectional area of the pipe instead of the diameter. When the diameter is doubled, the area is quadrupled.

 

[CHOMPERS]

My concern is the loc-line. It tends to have higher resistance due to the ribs inside. Increase the number of lengths of it so that it isn't the bottle neck (add enough so that the cross sectional area off all of the loc-lines add up to or exceed the area of the main plumbing).

I found the source of confusion. It's me. I'm thinking of a "length" of lock-line as X-number of segments. If you put two "lengths" in series (twice as many segments as before), then you will have twice the restriction. If you have two "lenths" in parallel (splitting the flow across two lock-lines), then you will have half the restriction.

 

[SpeshulEd]

No, that's backwards. You want them to be as short as possible, and you need more of them to reduce the restriction. Or split the water with another return method such as a spray bar.




(I'm selling a fish on Craigslist and dealing with some idiot tire kickers. If my grumpiness is apparent, it is not intended and I apologize in advance.)

I found the source of confusion. It's me. I'm thinking of a "length" of lock-line as X-number of segments. If you put two "lengths" in series (twice as many segments as before), then you will have twice the restriction. If you have two "lenths" in parallel (splitting the flow across two lock-lines), then you will have half the restriction.

No offense taken...i was thinking shorter would be better, thats why I was confused and now I think we're on the same path.

I have another hole I could use as a return. I'm using it currently to help with water changes. If I do a drip system, I won't need to worry about those. That should help out with less restriction and faster flow.

Awesome! Thanks!

 

[boldtogether]

Actually that's a common mistake. But don't feel bad, you are half right. It will take four 3/4" pipes to equal one 1.5" pipe. You have to use the cross sectional area of the pipe instead of the diameter. When the diameter is doubled, the area is quadrupled.

I am not doubting your obvious grasp at complex mathematical manipulation....but how did you know I felt bad?

Why do you double diameter? I thought area of a circle was (Pi)r2? A circle is what you get when you take the cross section of a pipe...if fact, if you wanted to know the volume of a given length of pipe, wouldn't that be (Pi)r2h? h would be the length?

 

[epond83]

IF you double the diamater you go

from (pi)*(.75/2)squared

to (pi)*(1.5/2)squared

Pipe sizing is the dia. and since you are squaring the results from doubling is quadruplied.

 

[CHOMPERS]

Ding, ding, ding. We have a winner.

Yep, that's exactly right. In a symbolic equation to find the resulting area after doubling the diameter (or radius), everything cancels out except for the two squared. Which is four.

 

[CHOMPERS]

Why do you double diameter? I thought area of a circle was (Pi)r2?

When you double the radius, you also double the diameter. You can't change one without changing the other. Picture in your mind a line that represents the diameter of a circle and two halves right above it (which are the two radii). When the two halves grow larger or smaller, the full line grows with them. If the two short lines are doubled, the full line will also double.

 

[boldtogether]

So using two 1/2" pipes is not the same as one 1"pipe?(scratching head...)How would one equally divide the the flow from a return pump utilizing 1"I.D. tubing?

 

[Toby_H]

So using two 1/2" pipes is not the same as one 1"pipe?(scratching head...)

That is correct, they are not the same...

using pi r^2...

One 1" pipe is : 3.14 * 1 * 1 = 3.14

Two .5" pipes are: ( 3.14 * .5 * .5 ) * 2 = 1.57


When you start squaring things it adds an additional dynamic to the math

How would one equally divide the the flow from a return pump utilizing 1"I.D. tubing?

I don't understand this question

 

[CHOMPERS]

I don't understand this question

I do.

...you would use a Tee.