Need Help With Invention

Knifecollector

I am trying to invent something and I need some help. I am trying to design a system that will determine the depth of water in a well. It will need to be accurate from one foot down to 500 feet. Needs to be about 1/2 inch in diameter so it can be installed along with the well pump. I'm thinking maybe a sensor mounted on the pump that determines and transmits pressure to a control box mounted inside the house. I believe it takes 2.31 ft of water to equal one psi. Not sure it would be feasible, just an idea I have been kicking around.

Rembrandt

We had some students come out to our Clubs lake and do a complete mapping of the lake bottom using sonar, found out where all the deep spots were and where it was silted in....neat system, but pretty expensive....would this do the same thing?

Knifecollector

Rembrant, sonar might be an option to consider. Most well casings are six inch in diameter and made of metal, not sure if this would cause false readings or not. I'm trying to keep cost at a minimum as these will be marketed to the local plumbers and well drillers, hopefully.

Judge Dread

I know !!! Eureka ! reinvent the lead weight and a verry long string !!

JD

Good...? , Bad...? Who cares ? as long I am the one with the the gun.....

Tailgunner1954

To be cost effective, what your looking for is probably a strain gauge pressure transducer (either PSIA or PSIG, A's read 14.7 PSI higer than G's) these can be made quite small and operate at 10 VDC.

The readout electronics would probably be the most expensive part.

What your trying to measure is the height of the water
colume above the pump head, correct? Not the distance from the surface down to the top of the water
colume.

It's about 33 feet of fresh water to equil 1 atmosphere (14.7 PSIA) or approx. 1/2 PSI per foot of depth

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Some guys like a mag full of lead, I still prefer one round to the head.

Edited by - Tailgunner1954 on 07/14/2002 18:34:43

Edited by - Tailgunner1954 on 07/14/2002 18:40:59

Knifecollector

Judge D, beat you to the puch on this one. That is the method I have been using but it is not very marketable. I was thinking the control box could have a series of LEDS , maybe one LED for each 25'. Maybe sound an audible alarm if the level drops below a preset level. Thus saving a pump burnout= $$$$.

Gordian Blade

I agree with Tailgunner, the sensor is the easy part, the read-out electronics is the hard part. If you just want a simple fail-safe to prevent motor burn-out, you could put a float switch just above the motor. But if you want an estimate of the water depth, you need to do more work. If you need it accurate to plus or minus one foot, down to 500 feet, that's only 0.2% error so you're really in for work. (If you can stand more error if the water column is high above the motor, then it's easier: like plus or minus 1 foot up to 100 feet above the motor, then plus or minus 5 feet after that, then at a certain upper level you don't care if it goes past that.) And you'll either need to be handy with electronics or have a friend who is.

Judge Dread

WELL lets get serious , a pressure transducer in the top of the pump
hooked to a water cooled water proofed Puck triac , low water level
at a preset point pump shuts down (triac does not trigger remains open to power line ) ....



Simple spartan and cheap .........

JD

Good...? , Bad...? Who cares ? as long I am the one with the the gun.....

dads-freehold

greetings, try this , get a stone aprox. 1" in diameter and drop it down the well, then count the seconds before it echoes back, for every 9.3 secs take away 1sec. leaving 8.3 secs. a solid falls at 8' per sec at specic gravity or 670 ft. in 8.3 secs. the echo back travels at 670 ft. per sec (speed of sound 630 miles per hour). respt submitted dads-freehold

rodney colson

COONASS

To measure water depth by pressure the best method is a pressure transmitter. Which will send back a 4-20 mA signal. You can set it so 1 foot = 4mA and 500 feet = 20mA. You can have these reading recorded on a chart 24 hrs a day , or just a LED read out. You can hook it up to the pump to turn off at a certain level, and if wanted can turn the pump on at a certain level. You were also correct , for every 2.31 feet of water it equals 1 psi. It can be in a 2" pipe or 200 foot dia pipe its still the same.


www.wika.com
www.globalw.com
www.pressuresystems.com

You can also look at www.waterworld.com for ALL you water needs.

Hope this helps..........coonass

We Live in a World of Give And Take, But A Lot Of People Won't Give What it Takes.

Tailgunner1954

CA
You and I think along the same lines, just using different terms that mean the same thing.
4-20MA yes, due to the length of the signal line, to much line loss in a 3mV/V system.
Transducer / transmitter, perty much the same thing.
2.32 feet per pound or .433 pounds per foot, same thing in reality (I was estamating in my earlier post) just depends on which one is easier for you to work with.
KUC
A 200-250 PSIG unit will cover your range (the 200 will be seeing a 8% overload with 500 feet of water over it, not a big deal as their normaly rated for 25-50% safe overload).
Most basic Load Cell Displays provide the exitation, programable display, and programable hi and low level limit outputs that can be used for controling the motor. One of these, the down hole pressure unit, some 4 or 6 strand signal wire and a buffer relay would complete the system.

I used to build tensile testers using Load Cells and/or Pressure Transducers, the technology is the same just the application is different. If I can be of assistance to you, feel free to e-mail me Tailgunner@M33Access.com

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Some guys like a mag full of lead, I still prefer one round to the head.

Knifecollector

Thanks for all the help. I like the pressure transmitter idea. I install well pumps in developments and need to keep a check on the water level in the well. If I can get the proper sensor I believe I can build the control box. I breadboard alot of circuits for various applications.

Alpine

My well was hand dug in the 1950s. It is 6 feet in diameter, 45' deep, and concrete lined. What I did was take a Stanley Tools Ultra Sonic measureing tool and put the transducer under the concrete lid, and run wires back to shop. When I want readings of how much water is over the pump I just press a button on the wall display, in the shop. Digital distance from under the lid to water surface, accurate to within 1/10 of a foot. I know the pump is at 40', so when I press the button and the water surface is 30' from lid, I know I have 10' of water over the pump.
With standard wells that have steel liner you will have to experiment to see if this would work for you.

"If you ain't got pictures, I wasn't there."

Lowrider

We have them all over the wastewater plant. Either the pressure transducer type that measures the head of water above the transducer or the sonic type that bounce a signal off the water surface. For the sonic type (Miltronics is the Brand we use most) you just program-in the distance from the transducer to the bottom of the well and after it bounces the signal off the water surface it calculates the actual depth of the water. The submerged pressure transducer type are a lot cheaper than the sonic type, however the sonic type are much more accurate.

Lord Lowrider the LoquaciousMember:Secret Select Society of Suave Stylish Smoking Jackets She was only a fisherman's daughter,But when she saw my rod she reeled.