PVC Flow Rates ?

[Bud8Fan]

I have searched but can't find a "good" graph, chart or calculator for determining drain flow rates on pvc.

I have two overflow boxes on my 300 that have openings for 2" pvc. I was hoping to get away with only using one of the boxes for the wet dry and utilizing the other for my inline canister and uv setup.

The 2" pvc will flow thru a Durso Standpipe then through no more than (3) 90 degree elbows on its way to the wet/dry filter. Anybody have an idea of a ballpark drain rate for this?

 

[johnptc]

it depends on how high the water is above the pipe,,,,,,,but i think 10gpm would be conservative.

based on a flow of 1 foot per sec in the pipe

I have searched but can't find a "good" graph, chart or calculator for determining drain flow rates on pvc.

I have two overflow boxes on my 300 that have openings for 2" pvc. I was hoping to get away with only using one of the boxes for the wet dry and utilizing the other for my inline canister and uv setup.

The 2" pvc will flow thru a Durso Standpipe then through no more than (3) 90 degree elbows on its way to the wet/dry filter. Anybody have an idea of a ballpark drain rate for this?

 

[Bud8Fan]

Thanks johnptc. What do you mean by how high is the water is above the pipe? The pipe will be a Durso standpipe in an overflow box.

How did you arrive at your 10 gpm? Just curious.

 

[Euge]

I always heard that a pvc pipe with a 1 inch diameter will flow 600gph. Since yours is 2" maybe 1200? I read this info in the PVC overflow thread. I don't know if it can be applied to your style tho.

 

[johnptc]

Thanks johnptc. What do you mean by how high is the water is above the pipe? The pipe will be a Durso standpipe in an overflow box.

How did you arrive at your 10 gpm? Just curious.

AT A FLOW OF 1 FOOT PER SEC PI R SQUARED= CROSS SECTIONAL AREA

PI*1*1X12IN/FTX60 SEC/MIN=2268 CU INCH PER MIN

231 CU IN = 1 GALLON

2268/231=9.8 GALLONS PER MIN


IF THE WATER LEVEL RISES ABOVE THE OPEN PIPE
THERE WILL BE MORE PRESSURE AND HENCE MORE FLOW

5 GALLON PER SEC IS A GOOD FLOW RATE IN PIPES...MUCH BEYOND THAT TURBULENCE STARTS....

I GUESSED THAT 1 GALLON PER SECOND WOULD BE CONSERVATIVE FOR OVER FLOW.....COULD BE MORE AND WILL BE MORE IF THE WATER LEVEL RISES HIGHER....THE LEVEL MUST BE HIGHER TO DRAIN AT ALL........THE HIGHER ABOVE THE OPENING THE FASTER IT WILL DRAIN..........

 

[Bud8Fan]

Thanks. No need to yell.

I was just curious as to how you arrived at your answer and appreciate the response.

Isn't 1 foot per second kind of slow? I took out a ruler and counted a second while I moved my finger from one side to the other. I could be wrong, just ask my wife.

 

[repair]

I have seen the flow rates for diff sized pipes and i think that your figures are low. you have to take into account that it will start a siphon and out flow the rates you have listed.

Jehmco gave me the figures.... I'll try and find them

 

[johnptc]

no doubt. at 5 ft sec it would be 50 gpm

I have seen the flow rates for diff sized pipes and i think that your figures are low. you have to take into account that it will start a siphon and out flow the rates you have listed.

Jehmco gave me the figures.... I'll try and find them

 

[johnptc]

I have seen the flow rates for diff sized pipes and i think that your figures are low. you have to take into account that it will start a siphon and out flow the rates you have listed.

Jehmco gave me the figures.... I'll try and find them

the flow from a 2 inch opening in the side of a tank under 0.1 inch of water flows 7gpm

 

[Bud8Fan]

Jehmco gave me the figures.... I'll try and find them

That would be cool.