Water Meters and Remote Sensing

I had a similar problem once.

I saw a doctor performing brain surgery and I thought I wonder if he could teach me to do that even though I would not understand what I was doing.

There are many of these available on the commercial market - best to buy one and examine its contents!

Thanks for the suggestion . I had already gone through many documents I wanted a little more than what I read from these .Few doubts about to clear if some knowledgeable person if available in this field to discuss with reference to http://www.edcheung.com/automa/water.htm Thanks

Dear Mr.Abraham. Here in India we have few domestic water meters which actually work. Before we go into remotely sensing the meter readings we need to design a meter which can stand Indian conditions. I had a go at this problem and found that it is the mud which often contaminates the water which clogs up the rotor of these meters. You see a new meter works until the water supply people dig up the road in the neighbourhood to repair some pipe; and then when they restore the supply we have to put up with muddy water for some time. The meter manufacturer says their meter is for metering water and not mud. In other areas the meter works so well that its reading goes up even when there is no water because of the air which comes out! So there are enough challenges without going into remote reading. And cheap manpower is one thing we have in plenty to be employed as meter readers. Any way don't worry about it. With all the foreign funding we go in for these days; these clever foreigners are bound to impose a good remote sensing meter on us costing more than the cost of most of our houses!!

Please note that ITRON in Spokane, WA is one of the leaders in remote meter reading technology and has been doing so for more than 25 years that I am aware.

http://www.itron.com/global/asia/en/asia_en_products.asp#MVRS

Hi Yanthram:

You could solve your problem of dirty water clogging the rotors of the water meter by using a magnetic flow meter. You will have to run an electrical supply to the meters but they work very well in dirty conditions.

mechtech

A typical model domestic water meter in India cost approximately $13. Mains electric supply in some places is only for 10 hours or less per day. You need to live here to fully appreciate the problem.

Mr.Yanthram I have been working in India and though I am Electrical Engineer I had additional charge of water supply distribution as Head of Engineering division. Water charge billing was one of the major labour dispute issue due to average charge billing due to defective meters and non availability of Meter readers. As you correctly said water contamination and poor quality of water is one of the reason for the defect. Another reason is that most of the houses remain closed now as both husband and wife are working. The municipal corporations in US is handling this problem with remote metering system.It is working very efficiently here. During my visit here at NJ I got interest in this subject and tried to find the possibility of manufacturing it in India .I think this simple technology could be implemented successfully there .Some percent of meters may remain defective due to water contamination and tampering of meters. (which could be solved separately).Considering the present conditions of our major cities poor water reserve of india and the wastage of water since occupents of the houses does not feel the pintch of the cost of water, we in India also have think to manufacture good quality water meters and remote metering units.These improvements are not that costly compared to the water wastage residents are doing in absence of meters.

Mr.Abraham, please don't get me wrong. I am all for improving the water meter. All I am trying to say is that we need to do it ourselves, and not import a solution from some country were conditions may be very different from our's. I am working in an institution (C-DAC, TVM) which is well capable of developing a remotely (I mean from up to 100m) monitorable water meter. I am just not sure of the economics. Who will pay the extra cost? At the moment we have yet to realise the true value of clean water. If you come from Kerala you will appreciate it all the more.

Mr.Yanthram .

Rahul Meters in Rajastan have started manufacturing this item in India
The technical details given by the company is given below I am contacting them :
"Remote sensing devices are bi-directional radio water meter reading system .It is composed of an emitter/receiver which may be clipped into water meters, and an emitter/receiver in association with a handled computer for index reading. It is a product of the latest developments in electronic technology. It combines radio technology with the lesser-known low consumption technology.

The radio communication technology employed ensures extremely high radio frequency stability over a long period of time. Some water meters are located in places with extremely difficult access, such as manholes etc in the middle of a busy street, With remote sensing devices these meters can be read without difficulty or time wastage. A manual reader is no longer required and reduces both invoicing errors due to discrepancies during reading, transcription and data entry, and totally eliminates unpleasant surprises related to approximations.

User is able to invoice quicker by eliminating all administrative procedures prior to invoicing. This time saving is reflected in the balance of the company accounts. There is no external wiring i.e. a considerable reduction in the risk of fraud as well as installation costs. Moulded in special materials, the electronic card is embedded in a totally sealed box made of thermoplastic material. Even in hostile environments such as muddy water, the electronic device is perfectly protected." you can get more information from the following link.

http://www.rahulmeters.com/

I have found my answer and am thankful to all for giving me the correct internet links.

I have read the site of Rahul Meters. But I am still not clear on how they avoid the difficulty with mud in the water. Are they some form of inferential meters? I know how remote reading works etc. But how is the flow sensed? What is the accuracy? I have been interested in this issue for a long time; and would be grateful if you could enlighten me. I am not asking for a tutorial on flow meters. I have a fair idea about all the well known types of meters. The question which has bugged me is how to make a flow meter with an accuracy of 0.5% or so which is immune to mud at a cost of less than Rs 1000.

Mr. Yanthram , I have no Idea how Rahul meters are manufacturing their meters . For making accurate flow meters ,they are to be Magnetic Flowmeters .I have no idea weather it is manufactured in India or how much it will cost.It may not be very costly.
Magnetic flowmeters are based on Faraday's Law of Magnetic Induction. In a magnetic flowmeter, the liquid acts as a conductor as it flows through the pipe. This induces a voltage which is proportional to the average flow velocity - the faster the flow rate, the higher the voltage. This voltage is picked up by sensing electrodes mounted in the meter tube and sent to the transmitter which takes the voltage and calculates the flow rate based on the cross sectional area of the meter tube.

The magnitude of the induced voltage is directly proportional to the velocity of the conductor width , and the strength of the magnetic field . Magnetic field coils placed on opposite sides of the pipe generate a magnetic field. As the liquid moves through the field with average velocity ,electrodes sense the induced voltage. The width of the conductor is represented by the distance between electrodes. An insulating liner prevents the signal from shorting to the pipe wall. The voltage generated is calibrated to required unit of measurement.

As there is no moving parts other than the liquid itself ,the accuracy will be good and quality of water will not affect the life of the meter.

Thank you Mr.Abraham. As I said I am conversant with the general principles of flow measurement and our institution has in fact built a ships log (which senses the speed of a ship through water) based on the magnetic sensing principle which you have explained. But I am not convinced about its feasibility of using it for a domestic water meter. My guess is (based on the pictures in their web site) Rahul meters sense the flow just as in the old meters we have here in Tivandrum with just RF remote sensing added on. If so there is no reason why they should be any more immune to mud.

Mr. Yanthram , In India magnetic drive water meters are manufactured with following specifications .

Single jet straight reading type, hermetically sealed water meter with magnetic drive.
Standard : ISO 4064 CLASS B
Construction : Brass Body & Coupling
Stainless Steel Cap & Lid / Plastic Cap & Lid

Manufacturers

M/S Progressive Thermal controls Pvt Ltd.

9-B, HSIDC, Sector-31
Faridabad - 121 003, Haryana,(India)
Phone. : +(91)-(129)-4042040,2276077
Mobile. : +(91)-(11)-9818201440
You can contact them for more details .There may be other manufacturers also.

The "magnetic drive" is for coupling the rotor shaft in the wet part of the meter to the counter shaft in the dry part of the meter. The rotor in the water has a magnet on it and when it rotates a similar magnet on the counter shaft rotates with it being coupled by the magnetic field; thereby avoiding the necessity for a shaft to go from the water to the counter in the dry part. It just avoids any possibility of the water entering the counter mechanism. As far as the actual sensing of flow is concerned the "single jet" has to spin a rotor or turbine; which I am affraid can be fouled up by mud. I think that is what Progressive Thermal Controls means by their specification.

Sensus Metering Systems has been the leader in technological developments in AMR (automatic meter reading) and AMI. They have been in the metering business for over 40 years.

http://na.sensus.com/Module/Catalog/File/water?id=363

http://na.sensus.com/Module/Catalog/Category?id=47

these are relativly simple devices that consist of a rotor that is installed into the water line,it has a specific gear ratio that determines the water usage,that information is acculated in a transmiter assembly,mathimatical equation, the transmitter has a preset frequency as the technician drives past your meter his transmitter recievor sends out a pole signal ,simply asking if the meter is there,the meter replys with its address and the number of gallons used,that information is feed into the computor and a calculation determines the usage from that previous reading.simple technology taht allows the technician to work smarter not harder.