Case Study: Flow Pacing Chemical Feed

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Introduction

Flow pacing chemical feed is a common problem in the water industry today. As many companies try to solve the issue not many succeed to the level we will demonstrate in this case study.

Objectives

1. Feed chlorine directly to the distribution system. Control feeding with DOSAGE [ppm]
2. Verify feeding rate with chlorine measurement
3. Document process with data logs

Equipment Used

1. GF Signet paddle flow meter used to measure water flow
2. Metering pump with 4-20 mA or 10V used to feed chlorine
3. Double junction Free Chlorine Ion Selective Electrode (ISE) used
4. Borynet Data Control Server (DCS) with U3 DAQ and attachments

Solution

Due to an unique feature of the Borynet Data Control Server (DCS), all functional segments of this complex assignment were accomplished with editing the configuration file of data acquisition and control service called IOMON. The IOMON allows to configure real analog and digital I/O signals. It also allows to define parameters and “virtual” signals based on mathematic formulas.

Using these features, output to the metering pump has been defined as a direct formula over the water flow and user defined chlorine dosage. Additionally, an input signal from ISE probe (direct) or through existing metering devices can be used to verify the feeding. If the feeding, gets out of the expected range either an alarm notification can be raised or the whole flow process stopped. Using standard logging features, all signal values were logged and saved on hourly basis for future reviews.

Conclusions

A solution comparable to custom PLC program development has been achieved with low economic means. Standard remote features allow for remote 24/7 monitoring.