Analyser measures near zero levels of chlorine

Paul Boughton

The plug-n-play DC80 De-Chlorination Analyzer, from Electro-Chemical Devices (ECD), utilises a zero-shift method to ensure stable and reliable chlorine measurement. It is suitable for de-chlorination applications, including municipal water systems and industrial cooling water.

Conventional amperometric chlorine sensors are unstable when measuring near zero amounts of chlorine, which can lead to inaccurate and inconsistent readings.

The DC80 De-Chlorination Analyzer utilises a ‘zero-shift’ methodology to provide accurate measurement and to protect total chlorine sensors from damage, which naturally occurs when the water samples measured contains near zero or zero levels of chlorine.

For example in wastewater treatment when monitoring for chlorine just before outfall, there can be no chlorine present and yet measurement is still necessary. If there is no chlorine present then the electrode becomes unstable and finally unresponsive. Therefore the very process of measuring de-chlorination becomes problematic.If all of the chlorine is removed then the sensor will provide an inaccurate reading after a few hours and fail after a few days still reporting zero chlorine.

The DC80 De-Chlorination Analyzer solves this problem: It is a total chlorine analyser that uses the ‘zero shift’ strategy to monitor near zero amounts of total chlorine. Chlorine is metered into the sample shifting the zero from a near zero chlorine concentration to a measurable value. The analyser’s offset feature allows the metered value to be subtracted from the measurement.

The DC-80 De-Chlorination Analyzer monitors chlorine in drinking water, wastewater, cooling water and other de-chlorination applications from 0.05–20ppm. Its mounted system includes built-in flow control, which eliminates the need for complicated plug-and-play design installs quickly right out of the box.  The DC80’s advanced panel pressure regulators and rotometers.  Built-in automatic pH compensation for samples between 4 and 12 pH also eliminates the need for expensive reagents to reduce maintenance and life-cycle costs.

The analyser’s total chlorine sensor is a three electrode amperometric sensor with a gold cathode, silver halide anode and 304 stainless steel counter electrode. The counter electrode provides a stable base potential that minimises drift for superior accuracy. The total chlorine sensor has a micro-porous membrane that allows ions to diffuse in and out of the sensor.

The analyser’s pH sensor provides accurate compensation for samples between 4 and 12pH, which eliminates the need for a sample conditioning system. The total chlorine sensor graphically displays both the total chlorine and pH levels for easy trend analysis. 

The DC80 Analyzer is available with either 110-240VAC or 24VDC power. The standard configuration features dual measurements, two 4-20 mA outputs and three alarm relays. The user friendly DC80 also is available with an auto clean option that includes a solenoid actuated spray cleaner using either 30 psi process water or air. An easily adjusted timer controls the period and duration of the cleaning cycle.