Sensorex Free Chlorine Measurement
Free chlorine refers to chlorine that is present as hypochlorous acid (HOCl) or the hypochlorite (OCl–) ion. When the chlorine demand of water is satisfied, the remaining free chlorine is available to oxidize contaminants, which is measured by a Free Chlorine sensor.
Like all halogens, chlorine is a highly reactive element. In solution, chlorine can be found in many different molecular forms. When chlorine is added to water, it reacts with organic materials and metals, forming combined chlorine. Because combined chlorine is not available for disinfection, this effect is called the chlorine demand of the water.
Why is Free Chlorine Measurement Necessary?
Free chlorine measurements are one of the most important measurements in the water industry today. These measurements ensure an adequate amount of chlorine is available for disinfection purposes, and in some cases that the chlorine has been removed.
Swimming pool disinfection
Wastewater treatment
Cooling water disinfection
Drinking water safety
Sanitising production lInes
Ballast water treatment and post treatment
Vegetable washing and disinfection
How is Free Chlorine Measured?
Many people are familiar with DPD test kits for measuring chlorine. DPD is a reagent that reacts with chlorine and produces a red color. While DPD test kits may suffice for simple applications, this methodology does not distinguish between free chlorine and combined chlorine in solution. For applications where the free chlorine concentration is critical for disinfection, the most robust measurement technique is the use of an amperometric free chlorine sensor.
An amperometric sensor design consists of two electrodes (anode and cathode), a membrane and fill solution. These sensors measure a change in current caused by the chemical reduction of hypocholorous acid (HOCl) at the cathode. The current flow of this reduction is proportional to the chlorine available. A membrane and electrolyte help to control the reaction. Constant flow rate and pressure are controlled to ensure an accurate measurement.
In some applications, oxidation reduction potential (ORP) measurement can be used as an indicator of free chlorine concentration. Because free chlorine is an oxidizer, ORP is a measure of free chlorine sanitization activity. Measuring ORP as an indicator of free chlorine is especially popular in swimming pool monitoring applications.
FCL
Free Chlorine Sensor, Amperometric
Chlorine exists in different chemical forms in solution, including free chlorine (hypochlorite ion and hypochlorous acid) and combined chlorine. Free chlorine is the only form that can perform disinfection, so knowing free chlorine concentration is critical for applications like water and wastewater treatment. FCL free chlorine sensors from Sensorex provide a direct measurement of free chlorine in parts per million (ppm). Using field tested amperometric technology, our FCL sensors perform continuous monitoring without any additional reagents. With a direct 4-20mA output, the FCL sensors can be used with any instrument accepting a 4-20mA input or connected directly to a PLC or SCADA.
- Reliable amperometric sensor technology: Easily monitor free chlorine (ppm) without using reagents
- Real time continuous measurement: Simple process control with direct 4-20 output
- Integrated automatic temperature compensation: Onboard compensation for changes in temperature to derive output signal
- Maximum sensor lifetime: Large electrolyte reservoir with easily replaceable membrane caps & fill solution
- One year limited warranty
Recommended accessories:
- Maintenance Kit (FCLA-5018): Maximize sensor lifetime by easily replacing membrane cap and fill solution
- Flow Cell (FC72): Maintains laminar flow across membrane and prevents air bubbles
- Flow Regulator (FM001): Provides consistent flow for added system stability
CLD
Chlorine Dioxide Sensor, Amperometric
The dependable chlorine dioxide sensor features amperometric measurement technology. Designed for use in disinfection applications. Sensor directly outputs a 4-20mA signal for easy control system integration. Maximize sensor lifetime by easily replacing membrane cap and fill solution (FCLA-5018). Use with FC72 Flow Cell is highly recommended. An optional flow meter (FM001 Flow Regulator) is available to provide consistent flow for added system stability.
- Reliable amperometric sensor technology: Easily monitor chlorine dioxide (ppm) without using reagents
- Real time continuous measurement: Simple process control with direct 4-20 output
- Integrated automatic temperature compensation: Onboard compensation for changes in temperature to derive output signal
- Maximum sensor lifetime: Large electrolyte reservoir with easily replaceable membrane caps & fill solution
- One year limited warranty
