Pool Opening Problems.

[PoolDoc]

My bad; should have scanned back for the pictures.

Using the Hazen-Williams calculator here, for the pipe between the pump and the filter (3xL; 1x branchT; 8' pipe => 20' equivalent length), I get a head loss of 9ft at 80gpm and 11ft at 90gpm. Using the Hayward chart I sent you, Mark, I calculate the drop through the dumb-head Tee layout as 3.5ft at 80 gpm and 4ft at 90 gpm. Estimating the equivalents lengths of the 1.5" piping to the pool at 50ft, and splitting flows evenly at 40gpm each and 45gpm each, I find a loss of 6 ft at 80gpm and 8ft at 90gpm

Taking filter pressure at 49ft, I estimate TDH around 57.5 ft @ 80 gpm(9+3.5+6=18.5) and 62 ft @ 90 gpm (11+4+8=23).

also used Charlotte Plastics Design manual

[Watermom]

Aren't you guys thankful for your math teachers!

[PoolDoc]

Honestly, I didn't learn to USE math until I was (a) taking engineering classes and (b) simultaneously doing repair work and realizing that I could use some of what I was learning in class to make my work easier.

[Watermom]

understand of how to use math in their daily lives.

That is something I talk about with my students every day. There is no reason to learn math unless you have a use for it. (Of course, some of my smarty-pants kids say then that they shouldn't have to learn it because they have no use for it!) Some day ..........

EDIT --- Rereading that it sounds backwards of what I was trying to imply but you guys know what I mean. My excuse for lack of clarity is that my mind is not on what I was writing right now cuz we are off to Baskin Robbins to get an ice cream cone!

[PoolDoc]

There is no reason to learn math unless you have a use for it. (Of course, some of my smarty-pants kids say then that they shouldn't have to learn it because they have no use for it!) Some day ..........

Make 'em do pool problems . . . !

Concentrations, ratios, flow rates, complex volume calculations (liner pools are easy, because they are all straight sides or radius curves, so bright middle school students possess the basic black-box tools to do the calcs), and so on.

[mas985]

Sorry, I was being a little lazy and not running full head calcs. I thought you were interested in an upper limit. But from the picture, it looks like the suction pipe is 2". So if you want full head calcs I need some additional information. If you have already given please post again so I have everything together:

Pump elevation relative to the water level (changes meaning of filter pressure)

Also, I don't remember reading the length of the suction runs. So how long are these and is the diameter 2"?

Filter pressure is 20 PSI correct?

[PoolDoc]

Pump is 2", but you can see the 2x1.5 insert adapters in the inlet & outlet.

Oops. Not quite.

The valve is a 1.5" valve with 2" fittings over the valve -- that would reduce suction flow loss on those segments a lot. Pipe from valve to pump is also 2". But, pipe from pump to filter is 1.5".

Sorry.

[TheGoose]

Suction piping is 2" from the pool. Dual skimmers, one on the near side and one on the far. Pump is at ground level, no more than 3' from the pool level to the pump, probably less than 2' total. Approximately 20-30 ft between the near skimmer and the pump. Filter pressure is ~20 psi clean and I normally backwash about ~28 psi.

Sorry, I was being a little lazy and not running full head calcs. I thought you were interested in an upper limit. But from the picture, it looks like the suction pipe is 2". So if you want full head calcs I need some additional information. If you have already given please post again so I have everything together:

Pump elevation relative to the water level (changes meaning of filter pressure)

Also, I don't remember reading the length of the suction runs. So how long are these and is the diameter 2"?

Filter pressure is 20 PSI correct?

[Watermom]

Make 'em do pool problems . . . !

Concentrations, ratios, flow rates, complex volume calculations (liner pools are easy, because they are all straight sides or radius curves, so bright middle school students possess the basic black-box tools to do the calcs), and so on.

Actually, I do. In the past couple of weeks, we have been doing some geometry. They have calculated the circumference of my pool, area of my pool floor, surface area of my pool (cylinder), etc. They all wanted to know if they could come over and swim when school is out. Uh............ I don't think all 140 of y'all are gonna fit in my pool!!

[PoolDoc]

Great!

But what about volume, in both SI and US. And weight! Have a bag of M&M's and give it to the person who can best estimate the volume in 60 seconds.

And flow rate, in GPM, LPM and pounds per hour.

And, from the weight of sand in your filter, the average grain size (0.50mm), and the mass density of quartz, and an assumption of a grain shaped like an equilateral 4-sided pyramid (doubled) . . . calculate the number of sand particles in your filter!