Liquid level sensors and control 1

[suntop]

We are desining a water pump station that feeds regional reservoirs.Those reservoirs are spaced about 10-16 Km from the pump station.There is no power source available or close to the reservoirs sites.How can we install and operate the control system for starting and stopping the pumps by a feedback signals that indicates to the water level in the reservoirs.
please advise of any ideas what do we need to make this thing possible.

Thank you

 

[dadfap]

suntop

Best bet is to use photovoltaic panels with battery support for cloudy days and night times.

This is a common method for remote power applications in Australia and many other countries around the world.

All the best

DADFAP

 

[jbartos]

Suggestion: Depending on a size of the reservoir, the following electrical power generation may be considered:
1. Diesel generators
2. Wind power
3. Solar (as mentioned in the previous posting)
4. Fuel cells
5. Etc.

 

[busbar]

The communication mode between reservoir and pump controller is not mentioned. It may be possible for metallic [“leased-line”] telephone pair(s) to provide excitation for the level sensor.

 

[PUMPDESIGNER]

Where are you?
As busbar asked, do you have hard wire? If so is it coax or paired?
Radio will work but is more expensive on original cost.
Motorola makes an inexpensive system called Irrinet that would easily do it with radio.
Solar is probably the way to go, we do it all the time, cheap and reliable, more so if electrical surges are present.

PUMPDESIGNER

 

[suntop]

Thanks to all of you helping me to get more thoughts and ideas about this control system.As for the availability of communication media,the answer is no.The only way is to use a radio system.But this brings the following questios:-
1.What is the operating frequency,if it needs prior approval?
2.The rough estimated cost of this system and recommended manufacturers?
3.Any special power requirements for the radio system to keep it available along with the sensors all the time?


Thanks again to all of you

 

[OperaHouse]

Nothing will be cheap. One low tech way is to also run a small plastic tube along with the pipe. Sure it is miles (km) of it but this isn't going to be cheap anyway. You then connect this to a larger pipe mounted vertically and submerged at the pond. A small air compressor at the pump site pressureizes the line so it bubbles at the other end. Depending on the depth of the water, the air will be at a pressure based on the column of water it has to push on of this "pressure relief valve". System wouldn't have to run all the time and could be on a timer. Would require periodic maintenance to clear growth in the sense tube, the reason for the larger diameter.

 

[cbarn24050]

Hi, put a pressure sensor on the pipe at the pumping station end.

 

[ERaySir]

Dadfap has a good idea,

A 100VA apc ups would work well with the right size photovoltaic panels and a radio link back. Motorola makes one.

Let us know what the final design is.

Ray Micallef, P. Eng.
Power Generation/Utility Industry

 

[jbartos]

Suggestion/question: How many reservoirs are there, and how close together? It may mean two power supplies per reservoir, or two power supplies per all reservoirs, or etc.

 

[jraef]

suntop,
I agree with others suggesting solar power and radio. Do an internet search using the terms "radio SCADA". SCADA stands for Supervisory Control and Data Aquisition, a catch-all term for remote control systems over long distances, pumping being the biggest market for it (another older term for it was "radio telemetry" but that will get you a lot of hits that are unrelated to your needs). People in the SCADA industry are very attuned to your exact problems and offer many low powered systems that come with solar power sources and radio transmitters.

A word of advice, be very thorough in your thinking of failure modes, try to cover all of the important "what-ifs" with regards to loosing communications because it WILL happen.

You still need to divulge your general location on the planet if you want anyone to be able to address your questions about cost, licensing etc. I can assume that since you used kM for distance measure that you are not in the US, but that leaves a lot of different currencies and radio regulations to guess at!

FWIW, I have seen a very innovative solution to your problem back in the days when solar was unrealistic. A farmer put a water turbine generator at the reservoir end of the fill pipe feeding a battery charger and a bank of lead-acid car batteries used to power his level controller and radio. His feed pipe dumped into the top of the reservoir, passing through the turbine first, which re-charged the DC system. By using a small pipe he had the water flowing for long enough periods of time to effectively charge the system at a rate roughly equal to the power consumption rate. Later on I heard that he added a small wind generator to suplement it because he discharged the batteries too often.

Quando Omni Flunkus Moritati

 

[jraef]

Follow up:
In a previous similar thread, someone else posted this website as a low-cost solution provider.

http://www.omnexcontrols.com/

I have no personal experience with them so I can't make a recommendation, but its somewhere to start.


Quando Omni Flunkus Moritati