Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

water well dynamic water level tester. How to make this work.

Status
Not open for further replies.

fastline

Member
We want to be able to test the water level in a water well at both the static (pump not running) and dynamic (pump running) levels. The issues are that wells will have either a pump shaft or Ethylene pipe in the center of the bore. Another and probably bigger issue is the static might be easy enough to detect with a photo or IR sensor but dynamic levels will certainly be turbulent with water dumping in from the perforations in the well casing as the level drops. This obviously might not give a good read or opportunity for a laser reflection.

Wondering if anyone even has a electronic idea on something like this or if a mechanical system is the only thing that can work? Obviously removing the pump for any installation is just not practical. Most people would try to use a string with something on the end but in my experience, it it just a guess because it is hard to detect when you touch water with it.
 

Reloadron

Well-Known Member
Most Helpful Member
How deep?
 

fastline

Member
Statics as shallow as 12ft, dynamics as deep at 150ft. Accuracy to 1ft or so would be more than sufficient.
 

ronsimpson

Well-Known Member
Most Helpful Member
I used a sump-pump float. Some of them are quite "adjustable". I have the thing set to turn off the pump when there is 1 foot of water over the pump and turn back on then there is 4-5 feet of water. very low teck.
 

squishy36

New Member
Folks who haven't worked around a well don't understand the challenges, especially with a pitless adapter, pipe, and wires running down the center of the thing... I've used a weight on a string to measure static levels to around 40'. But this was only possible when the mentioned crud wasn't in the way. I also used a mirror to shine sunlight down the well so I could see what was going on -- you can see when the weight breaks the surface of the water.

I could see an acoustic or optical solution working if the engineering was done right. If you have line of sight, a laser distance meter would be an easy thing to try.

You might try calling companies who dig wells and install pumps to see if there are any commercial solutions that would be in your price range (or if there are any such products at all).
 

ronsimpson

Well-Known Member
Most Helpful Member
You should be able to bounce a sound pulse down the well and hear the return. or Resonate the air in the well much like musical instrument.
 

JimB

Super Moderator
Most Helpful Member
If you measure the pressure at the bottom of the hole, you can calculate the head of the water above the pressure transmitter.

JimB
 

ronsimpson

Well-Known Member
Most Helpful Member
JimB
That works when the pump is off.
If the pump is on.....pressure at bottom-pressure at bottom??????
 

fastline

Member
You guys are on it! Really appreciate it. I thinking about both solutions, the pressure might be the most accurate but the acoustic method could be easier. However, I haven't a clue how to make an acoustics device such as this. Would it be as simple as generating a known frequency with a micro speaker, then using another speaker as a "passive radiator" to generate it's own frequency and measure that? I would be most concerned with cross talk of the signal source. Maybe I am missing something.
 

ronsimpson

Well-Known Member
Most Helpful Member
There is a common method where a pulse is output and the time to get it back is measured. At one time National made a IC to do this.
 

alec_t

Well-Known Member
Most Helpful Member
Is the pump at the bottom of the well, or part way up?
 

fastline

Member
Ron, if you have any more info on that IC, I would certainly appreciate. A name they might call that. "sonar IC"??
 

squishy36

New Member
If your well is the type of wells I've seen (steel casing, say 4" to 8" diameter), I'm guessing you'll have some problems with acoustic detection because of the scattering that will occur with the stuff going to the pump. But the only way to know is to try. I've pulled my pump out and I've banged on the casing and listened to the reflections, so the basic idea is sound (no pun), but the devil will be in the details.

Again, I think one of the best things you can do is to call some local pump places and see if there are any commercial tools available.

I like the idea of measuring the water pressure (nice idea, JimB!), as it stands the best chance of being simple and giving meaningful measurements with the least amount of work. I acknowledge Ron's concern about the pressure measurement when the pump is running, but I think the effect will either be negligible or could be corrected for. A letter to a pump company's engineering team might get some results.

In fact, next time I pull my pump, I'm going to put a pressure sensor on the outside of the pipe just above the pump and try this method.

BTW, I've pulled a few pumps up and have learned how to do it manually -- it doesn't take sophisticated equipment as long as the pump's not too deep or the thing's too heavy. It's something technical folks can do with a little care. If there's any interest, I'll write up a blurb on the things I've learned about it. A nice thing about doing your own work is you know the thing was done correctly with the right parts.
 

ronsimpson

Well-Known Member
Most Helpful Member
Squishy,
I can see that a 8" casing with a 4" pipe in it might not reflect back well. (sound)
I believe the air in the casing will tend to resonate. A speeker + signal generator and sweep from 100hz on down to 1 hz and I think you will find a resonate point that is related to the depth of the water in the well.

My well is not 8" but 8 foot across. I just use a float attached just above the pump.
 

Boncuk

New Member
JimB
That works when the pump is off.
If the pump is on.....pressure at bottom-pressure at bottom??????

What is measured using a pressure sensor is the height of the water compressing the air column in the pressure hose.

A differential pressure sensor would be a good solution since the hose just needs to be 4/6mm (inner/outer diameter).

Using PU (polyurethane) for the pressure hose it is stiff enough to be inserted into the water pipe without bends.

Here is a sample circuit for a precise differential pressure transducer.

Boncuk
 

Attachments

  • PRESSSURE-TRANSDUCER-SCH.gif
    PRESSSURE-TRANSDUCER-SCH.gif
    19.6 KB · Views: 177
  • PRESSSURE-TRANSDUCER-BRD.gif
    PRESSSURE-TRANSDUCER-BRD.gif
    26.1 KB · Views: 156
Last edited:

alec_t

Well-Known Member
Most Helpful Member
I'm not clear how a differential pressure sensor can sense water level. If inserted in the pump flow-line it will sense mainly (only?) the pressure drop due to flow resistance of the pipe, i.e. a function of the pipe diameter, pipe length, flow-rate, and fluid viscosity.
 

pilko

Member
You don't install it in the pump flow line, you install it in the well, so that it measures the head of water above it.
You may also be better off with an absolute or gauge pressure sensor, then you don't need hoses down the well -- just the signal cable.

pilko
 
Last edited:

MrDEB

Well-Known Member
measure the water level the KISS method
well diggers just use an ohm meter. Get a pair of wire leads, tin the ends to prevent corrosion. add a weight to the end.
Drop it down the well and when the tinned ends hit water the ohm meter will indicate a resistance.
just one wire will work as well. One end tied to earth (well casing (metal) and other sent down the well.
To measure the dynamic level, have two probes, one deeper into the water when running.
To make readings easier, use an op-amp top amplify the resistance readings.
 
Status
Not open for further replies.

Latest threads

Top