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geochuck
September 12th, 2007, 01:29 PM
I need a Digital Flow Meter for my swim-in-place-pool. Does anyone know a manufacturer who makes them? It should measure the flow that comes out of the propulsion unit.

Who has a good swim meter? Something to measure miles per hour etc.

scyfreestyler
September 12th, 2007, 01:38 PM
A digital fluid flow meter is expensive in my experience. I suppose you could call your local water company (utility) and ask them to rent a fire hydrant meter that you could plumb into your system. It will most likely be analog but with a stopwatch you can figure out an average flow.

Rob Copeland
September 12th, 2007, 04:24 PM
If you are handy you can build An Inexpensive, Fast Response Current Speed Indicator.
http://estuariesandcoasts.org/cdrom/CPSC1973_14_3_217_219.pdf

Matt, I don’t know if the water company’s flow meters are calibrated for such low rates of flow. We are talking about speeds of 1 to 3 MPH not the speeds generated by 150-200 PSI water flows.

And if you are feeling inventive there are cheaper solutions. Take a large clear plastic cylinder; suspend a thick colorful disk inside the cylinder with a light spring. The disk should be slightly smaller than the cylinder and use 3 points of attachment from the spring to the disk to keep it stable during use. Place marks on the cylinder where the disk hangs (0 MPH) then where it I a t 1, 2, 3 and 4 MPH in a controlled environment. The lighter the spring, the greater the distance between MPH lines.

geochuck
September 12th, 2007, 06:05 PM
Thanks that is a good start. Endless pools had one or still has one it cost close to $300. I would really like to know who manufactured that one and if there are any comparable or better on the market.

scyfreestyler
September 12th, 2007, 06:15 PM
How large is the discharge? I was assuming that we were talking about something with more force than 1-3 MPH. Current water meter technology will allow you to detect a leaking toilet in a customers home...they are pretty darn accurate. You just need to determine what size the dischage is so that you wind up with the correct sized meter.

Having said that, the meter that is buried outside your home probably costs more than three hundred dollars so you might be well served to just buy what the manufacturer is selling.


Another thought...plumb a hose into a 5 gallon bucket and see how long it takes to fill. This is common practice for testing the flow of residential/homeowner wells.

geochuck
September 12th, 2007, 06:23 PM
The flow meter should tell how fast the flow is inside the pool. The one in the endless pool had a small rod that is set in the water flow that is coming out of the propulsion unit. It is attached to a Digital display and tells how fast the current is, eg 100 yds in 1 minute or 100 yards in 1.5 min or what ever speed the propolsion unit is set at. I believe it has a little rotor that turns with the flow.

scyfreestyler
September 12th, 2007, 07:18 PM
I see, I kept reading flow...you really want velocity. Two very different things with respect to water.

Velocity=Flow(GPM)/2.45 x ID squared (in inches)

As I recall, velocity is always measured in fps. You will need to make a seperate conversion to MPH.

There are some other formulas as well that might suit your situation a little better. Just search for some water technology websites.

scyfreestyler
September 12th, 2007, 07:28 PM
Velocity in feet per second = (0.408 x GPM) / Inside diameter of pipe in inches, squared

Here's one I found online. Good luck.

poolraat
September 12th, 2007, 08:10 PM
The flow meter should tell how fast the flow is inside the pool. The one in the endless pool had a small rod that is set in the water flow that is coming out of the propulsion unit. It is attached to a Digital display and tells how fast the current is, eg 100 yds in 1 minute or 100 yards in 1.5 min or what ever speed the propolsion unit is set at.


It sounds like you're describing a Pitot tube which is used to measure velocity of liquids.