Flow Meter / Computer generated reports

[ChickenEngineer]

Ok, I'm a mechanical engineer but I need to install some water meters.

I have 2 4" water mains coming into my plant. They are flowing approximately 500-700 GPM each and are at 80 PSI. I would like to install two meters and feed the data into a computer to generate water usage reports for set time periods. My first step is finding meters, probably with a 4-20 ma out put.

I have heard there are meters that "piggy back" on the city meters and the only specification I need is they are 4" lines. I've looked far and wide for there water meters, but I can't find anything that looks like they piggy back off of city meters. Any input? What are they called specifically?

Any input on a software program that can handle this? I would rather not have to write my own...

Thanks!

 

[m777182]

I am sorry I do not understand the phrase "piggy back on the city meters " but however I would take flowmeters with RS232 output and link them directly to a PC.This way instruments can provide more information compared to 4-20mA output: units, self diagnostics and error messages and you can switch ranges, fit instruments inherent signal smoothing etc.
M777182

 

[ChickenEngineer]

Well, the way it was explained to me was the city has their meters they read on the lines. They are roto-type meters that are screwed into the top of the lines. I've heard there is a type of meter that we can unscrew the city meters, place this meter in it, and screw the city meter back on top of it. All the meter does is read the same rotation that the city meter is reading. It's basically just a switch that closes every time the city meter makes a rotation.

I've had it explained to me that these exist, but I wasn't given the name and in my search for meters I can't find anything like this...

 

[ReginaWWTP]

You can drive a 4-20mA signal off a typical utility meter (Neptune/Schlumberger) with the proper equipment that 'piggyback' off of the said equipment. Bringing that info into a 'computer' to evaluate is a bit of a trick, depending on the existing hardware that you have in place. M777182 is correct when saying a RS-232 connection is the way to go; for example, i have two of these units (I'll check the make/model and get back to you) driving a 4-20mA back to my PLC, which then in turn is picked up by my SCADA to drive out a usable signal and allow historical data capture and trending. Try this package that I found googling

http://www.tisales.com/pdf/PSFLOSEARCHa.pdf

Might get you started...

Sean

 

[hydrae]

ChickenEngineer

You need to find the brand of meter the city is using at your site, each brand has there own replacement resister that will continue to read a mechanical readout and produce a pulse signal, then that pulse signal can be converted to a 4-20 through another device provided by that meter company. Sometimes you can pick up the pulse signal directly from the meter, caution, some brands are picky about input voltages and will cook at 24vdc, with the pulse signal and PLC programming you can get your flow.

You will also need the city’s permission to touch their meter, and in most cases they can control or deny access.

Most water meters use a pair of magnets to transmit the use from the measuring device (chamber or turbine) to the register, there is a strap on magnet sensor that wraps around the register to pick up this magnetic movement, I have not seen it in action though, nor have I seen an ad for this device in the past few years.

For about $500 usd can install an insert meter with a control box (accuracy 10%) through a 2 inch tap, needs to be a straight run of pipe. The control boxes are self powered by the 4-20mA 24Vdc loop and can be calibrated to any size pipe. Variety of brands to choose from again available from most water works outlets including catalogs such as USA bluebook or Pollard water.

If you need greater accuracy, cut in a magnetic meter at a cost of $1000 per inch, typically has a higher accuracy than the city’s meters, and no parts to wear out.

Hydrae