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Re: [PSUBS-MAILIST] Speedometer
Hi Pierre,
Im a little confused, I think GPM = Gallon per minute... am I wrong?
I will assume that GPM = Gallon per minute.. and continue with the
conversion.
The best way might be to calibrate it using a boat with another flow
meter. i.e. tow your flow meter behind you at a range of known water
speeds and mark it off on the meter.
Alternatively:
To get from gal/sec to km/hr you have to convert between the antiquated,
outdated and useless Imperial system, to the system that the rest of the
world uses (derived and maintained by your ancestors, the French).
A gallon is about 3.8 litres (if you are using US gallons).
You need to know the cross sectional-area of your pipe, or more
basically, just the radius, R.
Since the water flow is just a flux, i.e. so many squared meteres x
meters per second, you can just multiply the flow rate by the cross
sectional area of your pipe.
Then you convert from cm/min to km/hr
So to convert from gal/min to km/hr you use this equation:
V=G*A*C
Where V is the velocity (km/s), G is the flow rate in gal/min and C is
some factor to convert between systems yet to be defined.
So, with
A=pi*R^2
(R is radius of pipe in cm)
and then,
C=F(gal to litres)*F(cm to km)/F(min to hr)
C=3.8*(1/100,000)/(1/60)
C=0.00228
so:
V=G*0.00716283*R(cm)^2
I think.
EM.
Ps.. I think the word you are after is 'throughput'
PPs.. I think you should get a large throughput system, since I imagine
there will be significant backpressure from small diameter pipes.
EM.
Pierre Poulin wrote:
Hi all!
I just had another "innovative" idea.
I just bought for my work a flow meter (Gallon per meter) And when
searching for it I noticed that it is also available in 0-2GPM.
Maybe we could use that to convert it to knots or KM/H or whatever. We
could just place the meter in the water with a small pipe on both ends
and watch the meter thruthht (can somebody tell me how to write that
word please?) the front viewport.
---------------------I------------------I---------------------------------
I flowmeter I
in pipe I gpm I out pipe
---------------------I------------------I---------------------------------
Any tough on that?
Pierre "looking for a manager" Poulin
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