We use water to cool electrodes in our glass furnace. The electrodes sometimes leak and have to be replaced. One of our first indicators is the amount of water treatment we add to the coolant.

We have 18 electrodes and it is difficult to establish which electrode is leaking. (it's no easy task to change the electrodes)

I would like to detect the flow in and out to alarm if there is a leak.
Is there such a thing as a differential flow switch / sensor I could use? Or are two separate sensors my only option? The cooling flow is between 5 an 10 gals per minute of R.O. water.

Thanks in advance

 

I work in the automotive industry doing RSW (Resistance Spot Welding) and use a DELTAPOINT (Rocon water monitoring system). The welding equipment will shut down when insufficient chilled water flow is detected.

web site http://www.roconllc.com/

> I would like to detect the flow in and out to alarm if there is a leak. <

Yes DELTAPOINT will do this for you. Flow is measured in and out with two vortex shedding flowmeters (no paddle wheels to jam) and then compared.

> The cooling flow is between 5 an 10 gals per minute of R.O. water. <

Talk to Rocon to see what model will work for you.

John

 

Paul,

For flow measurement, I would recommend two Sensus SR flow meters equipped with ICE registers. The 5/8" size is rated for 1 to 20 GPM, so it should be the right size for your application. Here is a link to the Sensus meter...

http://na.sensus.com/Module/Catalog/File/water?id=24

Plus one EtherMeter, which is a device that my company manufactures. The EtherMeter is capable of reading one or two compatible flow meters and converting the totalization and flow rate data into Modbus or Rockwell communication protocols.

You would then configure a PLC to read the two flow rates from the EtherMeter via Modbus, DF1, or EtherNet/IP, calculate the flow difference, and alarm any detected difference that exceeds a pre-set threshold.

The EtherMeter has an LCD display, so if you just want to observe a readout with the two flow rates, it will do that too.

If you'd like to discuss further, don't hesitate to call.

-Jim Mimlitz
SCADAmetrics

 

I am also looking for a similar device that Paul mentioned -- a device that measure the flow rates of in and out, and close a valve automatically when the two flow rates are different. The Rocon deltapoint seems to match my requirement, but it is too bulky and has too many additional function that I don't really need.

Jim, the EtherMeter that you recommended seems quite cool, which I can program the device. I would like to ask is the EtherMeter has a valve that will close itself when it detects a leak?

Best,
Tan Ting Rei
National Institute for Standards and Technology

 

Tan,

No, the EtherMeter doesn't have programmable logic for controlling a valve. But if you link it with a PLC via Modbus, the PLC could take care of the valve control.

If you already have a PLC, then great... otherwise any inexpensive PLC with Modbus should do (eg Automation Direct DL-05).

 

Tan,

If you have an Allen-Bradley PLC that communicates via DF1 or EtherNet/IP, that will work fine, also.