Below we answer questions regarding the DIS sensor measurement.
What does the Zirkon® DIS Free Chlorine sensor measure?
The Zirkon® DIS Free Chlorine sensor measures hypochlorous acid (HOCl), commonly referred to free chlorine. The sensor is a core component of a free chlorine measurement produced by the Kuntze Krypton® Multi analyzer.
What factors influence a free chlorine measurement?
All amperometric free chlorine measurements (not just Kuntze's) are subject to variables that either need to be controlled, buffered, and/or measured for compensation. A free chlorine measurement can be produced when the below variables are attended to.
Variables of Influence
- Flow - All amperometric chlorine sensors measure of differential current produced by the presence of chlorine against a measuring electrode that has an applied electrical potential. As a volumetric measurement, this requires a continuous and stable flow of water against the measuring electrode.
Kuntze removes the variable of flow fluctuations via the Argon Stabiflow sensor assembly. The Argon Stabiflow regulates flow to a stable 30 L/hr (8 GPH), removing process variables that may alter the flow rate through the sample line. - Fouling - All on-line analyzers are subject to fouling based on the conditions of the process. Particulates, organic, and inorganic contaminants may coat the sensor and obstruct the measurement.
Kuntze's patented ASR® technology reduces sensor fouling and can be automatically triggered up to 7 times a week. - Temperature - As with most water quality sensors, temperature and temperature fluctuations influence the signal strength of the sensors.
Kuntze measures and compensates for temperature fluctuations with a built in Pt 100 temperature sensor, which also acts as our flow indicator. - pH - As we, and other amperometric free chlorine sensors, are only able to measure the HOCl species of free chlorine, it's critical to take attention to the pH of the sample line.
Kuntze employs a continuous pH measurement to compensate for signal gain and/or loss experienced on the Zirkon DIS Free Chlorine sensor when pH fluctuates.
Below is a diagram that depicts the transformation of free chlorine at different pH values.
The above variables of influences are understood and explained in the EPA Method 334.0 document.