13 replies to this topic

[elcano]

It happened again today. The buoy valve on my water tank failed and the tank ovefilled. This is the second time on about 3 years, and another reason to automate the tank and pressure pump.

The other reason is that with the proper level sensor (ultrasound or pressure differential) I can convert my 500 gallons tank into a variable size tank. 500 gallons in good to have when you expect an hurricane, but overkill in most situation, specially on Mon-Fri whe we dont use as much water as the weekened for cleaning the house, etc.

The problem with a big tank is that if you dont use all the water in a few days it will loose the clorine and begin to grow bacteria. Another problem is the weight of all that water in the roof of my house (concrete house, flat roof).

So the sensor is easy and not expensive ($25 for the Maxbotic, analog output), and turning off the water pump when water level is too low is easy too with a simple relay. The question is about the electronically controlled water valve. The valve that controls water input to the water tank. The Watercop and other valves that can stay open or close without applying constant power are too expensive. So I was wondering about a simple irrigation valve. The flow specifications seems to be good at up to 15gpm or even 30gpm in some models. The other question is operating power. When I have really low pressure the tank might take the whole night and sometime more than that (the best pressure from the mains is during the night when few people is using water). Do you know how much power do those valves use? I will need that not only to know if I'm better with the expensive OFF/ON valves, but for sizing the power supply too.

What do you suggest? Any other ideas?

[BraveSirRobbin]

Elcano;

I'm not sure a typical sprinkler/irrigation valve will work out for you. I believe you need a pretty good pressure on the "front" end to control it going on and off.

What is your pressure leading to the water tank?

Power isn't that much though they are something like 24 volts AC operating.

As far as the analog output of the Maxbotix Ultrasonic Sensor, look at my reply to you in that How-To.

Regards,

BSR

[BraveSirRobbin]

BTW, what is the depth and diameter of your tank? I'm wondering if some kind of float/arm system rotating a ten turn linear potentiometer would work out better for you since you seem to be going the analog route...

[elcano]

The tank is about 5 to 6 feet diameter and about 5 feet tall. I have given tought to the potentiometer for long time without much results. The other option is the pressure sensor.

[elcano]

I'm not sure a typical sprinkler/irrigation valve will work out for you. I believe you need a pretty good pressure on the "front" end to control it going on and off.

What is your pressure leading to the water tank?

Pressure can be as high as 15-20psi during the nights and as low as 0-10 psi during the day. Being worst in weekends. I have never worked with those valves, so I dont know.

Does anybody come with an idea to open/close a 90 degrees ball valve using a motor or solenoid?

[FrankMc]

Hi Elcano

If its any help i can send a couple of the Coolon chips which use probes at different levels to monitor the water level......

http://tinyurl.com/hgak6

Whats the issue with using normal garden sprinkler solenoids...?? is the incoming pressure too high ???.....


Frank

[BraveSirRobbin]

I really think I would at least try the pivot with a potentiometer. You don't need a ten turn actually, just a cheap single turn one.

I flew through this drawing (yea, ignore the inches and pretend it's feet) but it would result in a "fairly" linear output except towards the bottom.

All you would need is a piece of sprinkler pipe, a pot, and a way to hold it towards the top of the tank. The sprinkler pipe would act as the float, the pot would go through one end of the pipe and "rotate" as the pipe "rotated" up and down through that pivot point.


(Click on Picture for Full Sized Image)
Float Inside Water Tank


(Click on Picture for Full Sized Image)
Graph Degree's Rotation vs. Water Depth

Edited by BraveSirRobbin, 18 July 2006 - 12:26 AM.

[tech-home]

My sprinklers handle 80 psi. that was the last time I tested it. I was told its near the upper limit for the rainbird.

If I was installing for your situation I would go with some type of commerical product.

[Steve]

Does anybody come with an idea to open/close a 90 degrees ball valve using a motor or solenoid?

Elcano, you can use a standard valve actuator for that. They are typically used on pools to open/close valves for solar, etc. My system uses the Jandy.

http://www.inyopools..._actuators.aspx

Edited by Steve, 18 July 2006 - 09:13 AM.

[Mike]

Depending on placement of this, and if you need the control aspects, couldn't you use a WaterCop? You can trigger the sensor to close the valve. It is a ball valve.

Seems that Steve's idea would be better unless something doesn't work with that approach. His is also cheaper.

[elcano]

I really think I would at least try the pivot with a potentiometer. You don't need a ten turn actually, just a cheap single turn one.

God bless your creativity BSR!
I think that it will be a little difficult to build/install, but anyway I never came with this simple idea. In all my designs I was trying a vertical floater on a stick, someway turning the 10-turns potentiometer. Kind of rack-and-pinion.

Obvioulsy other options like the ultrasound and the pressure sensors seemed simpler than my design. I'll give it some though.

[elcano]

His is also cheaper.

That's important. I have a working system right now, and water is not that expensive, so it is difficult for me to justify investing big money on this little project. My wife someway keeps the total amount that I have spent in HA in the past year. How is that she is not as good for mathematics in other topics?

I'll check the pool valve/actuators in eBay. I might find something there.

About the pressure, the point that BSR raised is that I have very low pressure, and this might not be able to operate the irrigation valve. That's why the ball valves are better for this application. Actually, I can work with small diameters without problems because the flow TO the tank is very small.

[elcano]

Elcano, you can use a standard valve actuator for that. They are typically used on pools to open/close valves for solar, etc. My system uses the Jandy.

http://www.inyopools..._actuators.aspx

Steve,

Do you know if the valve to actuator coupling is standard, or do I have to choose same brand? There are several brands to choose from at eBay.

The other thing that I noticed is that most of them seem to be 1 1/2 PVC pipe. I'll have to do a huge adapter to install the valve to my current 1/2 inch flexible copper pipe.

[elcano]

Steve - Another question. Do these actuator need to have power applied all-the time that you want the valves open? If not, how do you control the valve state? Inverting polarity? Do the actuator have limit switches?