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[SIZE=-1]Assume Gravity to Low Pressure. About 6f/s flow velocity, also suction side of pump[/SIZE] | [SIZE=-1]Assume Average Pressure. (20-100PSI) About 12f/s flow velocity[/SIZE] | [SIZE=-1]Assume "High Pressure" PEAK flow. About 18f/s flow velocity*[/SIZE] | ||||||
Sch 40 Pipe Size | ID (range) | OD | GPM[SIZE=-2] (with minimal pressure loss & noise)[/SIZE] | GPH[SIZE=-2] (with minimal pressure loss & noise)[/SIZE] | GPM[SIZE=-2] (with minimal pressure loss & noise)[/SIZE] | GPH[SIZE=-2] (with minimal pressure loss & noise)[/SIZE] | GPM[SIZE=-2] (with significant pressure loss & noise)[/SIZE] | GPH[SIZE=-2] (with significant pressure loss & noise)[/SIZE] |
1/2" | .50-.60" | .85" | 7 gpm | 420 gph | 14 gpm | 840 gph | 21 gpm | 1,260 gph |
3/4" | .75-.85" | 1.06" | 11 gpm | 660 gph | 23 gpm | 1,410 gph | 36 gpm | 2,160 gph |
1" | 1.00-1.03" | 1.33" | 16 gpm | 960 gph | 37 gpm | 2,220 gph | 58 gpm | 3,510 gph |
1.25" | 1.25-1.36" | 1.67" | 25 gpm | 1,500 gph | 62 gpm | 3,750 gph | 100 gpm | 5,940 gph |
These are the numbers used in the industry when rating overflow boxes.
Yes, I totally agree, when you have a siphon established. When you lose that siphon I wouldn't risk having to drain more water than a 1" pipe can handle. It's always better to err on the safe side. Also, a drain is much quieter when it is not running at max. capacity - I like quiet.Very conservative numbers. A short section of 1" with minimal restrictions will gravity flow much greater than 600 GPH when you have the proper air mix.
Just to clarify, this is 1" pipe going down about 12 feet into my basement. It is a herbie setup (full siphon).
So I am wondering how much flow I can expect to get with just gravity, no pumps.
If I go from 1" to 1.5" - 2" then back to 1" will it increase the flow at all?
Awesome...was just looking for this!generally, the number you most hear referred to is about 900gph. of course, there are variables and such, this is just a rough guideline.
Awesome...the pump I ordered is just over 1000 GPH; it's not the one for long term, but it will do to start.So the thread is 6 years old. Regardless, 1” siphon with significant drop will move more than 1,000 GPH. Mine, with about 10’ of negative head easily handles 1,100.
Ron,The short answer is, no.
It will help maximize the flow thru the 1" section if you back up some water in the 1.5" or 2" section of pipe. But it won't really improve the flow rate beyond what gravity can do thru a 1" pipe.
Can someone explain to me how this chart works for gravity flow. The chart is assuming 6 feet per second flow. The flow is going to change with the total drop of the water.
Bernoulli’s Principle formula is Velocity = Sqrt(2*g*h) which show the velocity is going to change with height.
Not well I think LOL. Perhaps a good starting point but as somebody that runs a basement sump the numbers are low.