Mag flow meter installation

[Waqalevu]

We are looking at cutting a concrete sewer pipe and installing a mag flow meter suitable for measuring flow in partially filled pipes. Anyone envisage any problems with installing the flow meter into concrete pipe, and will i need earthing rings?

 

[zdas04]

Maybe in the size you are talking about it may be a different device than I'm familiar with. In 4-inch pipe size and smaller, a partially full pipe will cause the reading to go to 20 mA instantly, and it only takes a very small amount of "not full" to spike the meter.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

 

[danw2]

My experience is similar for conventional magmeters. I wouldn't put a conventional mag in a partially filled pipe.

Krohne's TidalFlux mag claims to deal with partially filled pipes. I can't vouch one way or the other.

Krohne recommends a 'special' grounding ring, as you can see:

 

[Waqalevu]

The pipe size is 700mm diameter. I have used the Tidalflux in a couple of applications already and happy with the results, but that is with steel pipes. Thanks for the info on the grounding rings, looks like we will have to fabricate or buy the rings to suit our application.

 

[roydm]

You may not need rings, you just need some way of referencing the meter to the fluid, there may even be some local metal in contact that you could tie the meter to. We often work with meters in plastic pipes, just ask for a grounding electrode.
I'm sure the meter manufacturer can advise you on that.

 

[roydm]

The manufacturer indicates the meter will read from 10 - 100% full pipe.
It has a level sensor built in, be very careful with the installation, the terminal box must be at the top to get the elrctrodes and level sensor in the right place. I see they have a special grounding insert it's probably more for the level sensor than the mag so don't stray from that.

http://cclynch.com/cut_sheets/TIDALFLUX_4300.pdf

 

[AVosKROHNE]

@ Waqalevu
we are delighted to see your intrest in our TIDALFLUX flowsensor for partially filled pipes.
In the screenshot above from our technical data sheet you can see we recommend the use of grounding rings, in this case the rings have a dual function they are used for level measurement reference and for the flow. Main property is to provide refernce for the level measurement though. Unlike normal grounding rings these rings protrude inside the process piping instead of the flowmeter itself. Please take care to provide your Local sales office with the inner diameter of the concrete tubing.

If you have anymore technical questions about the device you can either contact our local sales office through our KROHNE website or ask me through this forum.

Kind Regards,
Alex Vos
Product manager TIDALFLUX
KROHNE Altometer