HSI’s TRO sensor has several advantages when used in seawater electro chlorination systems. Existing membrane amperometric and reagent feed systems have significant drawbacks in this application.
Featuring flow independence, self-cleaning electrodes, and long calibration retention are the HSI TRO sensor’s biggest strengths. The sensor employs three-electrode amperometry, bare electrodes, and an integrated cleaning system.
Wide Measurement Range For A Free Chlorine Sensor
The amperometric sensor can also measure total residual chlorine levels up to 20 ppm. A magnetically coupled pump in the sensor tip provides a fixed constant flow across the electrodes. All amperometric sensors are flow sensitive. Generating consistent velocity, sensitivity, and signal-to-noise ratio is better for lower TRO detection levels. The integrated pump uses a Brushless DC motor. The impeller is made from an engineered polymer formulation, creating low friction and long life.
Low Maintenance Amperometric Chlorine Analyzer
We use bare electrodes, eliminating the need to replace clogged membranes or replenish electrolyte required by conventional amperometric sensors resulting in much lower maintenance requirements. In competing for amperometric sensors, diluted electrolyte requires periodic sensor recalibration to compensate for this.
Low Maintenance - Self-Cleaning
Our chlorine sensor has a patented cleaning feature. Polymeric beads are captured within the sensor and abrade the electrodes to minimize biofouling and remove calcium carbonate that typically deposits on the electrodes during operation in seawater. The polymeric beads are motivated by the flow from the internal pump.
No Reagents or Waste Stream - Lower Cost Installation and Maintenance
HSI’s chlorine sensor does not require reagents or a waste stream, lowering maintenance and installation costs. Colorimetric systems, such as the Hach CL-17 require reagent replenishment every month and periodic replacement of pump and optical components. These can be difficult to troubleshoot, and the tubing is subject to biofouling requiring replacement. Reagents and parts can exceed $600 per year plus labor.
Accuracy from Freshwater to Seawater
HSI’s sensor measures five different parameters every minute: TRO, Oxidation Reduction Potential-ORP, pH, Salinity, and Temperature. The sensor uses these measurements to compensate for changes detected in the water source. While the pH of seawater does not change much, in brackish or freshwater, the pH can change drastically. Even when used in freshwater, the sensor can use conductivity measurement to compensate for signal changes. In addition, the temperature sensor allows the sensor to make compensation for all the parameters over -2 ° to 35 °C. These readings enable the sensor to operate and deliver accurate readings in virtually any water condition that a ship may encounter.
Better Reliability Through Electrochemical Cleaning
Our sensor’s electrochemical stabilization technique is unique. We use this technique to prevent the passivation of the electrodes. Passivation due to organic poisoning is a frequent problem with bare electrode amperometric sensors. This approach enables our chlorine sensor to stabilize and provide accurate readings, usually within one to two minutes. In contrast, our competitor’s bare electrode sensors require up to 24 hours after starting up for reliable readings.
Direct Pipe Insertion for fast response and lower cost installation
Our sensor measures water at velocities from zero to 4.5 meters per second with less than a 5% change in signal. It can accomplish this thanks to its integrated pump. HSI has the only total residual chlorine sensor capable of direct insertion into a pipe.
Eliminating the need for a waste stream simplifies the installation and maintenance. The Hot Tap version, shown in Figure 2, enables us to remove the sensor from the plumbing without the need to drain the plumbing. The Hot Tap installation method rids the use of a sampling pump, switching valves, sampling lines, and sample filtration. This method significantly lowers installation costs.
High Pressure, Rapid Wetting pH Sensor
Halogen uses a unique pH cartridge in its chlorine sensor system. The pH cartridge can withstand 10 bar to -0.7 bar pressures and rapidly wets if allowed to dry out, with its accuracy restored within 3 minutes. HSI is the only company with this type of pH electrode designed with these specifications in an amperometric chlorine analyzer. It does not require calibration for a year or more, and the cartridges should get replaced every two years.
Novel Patented Technology
Halogen Systems Inc.’s research and development of this novel technology have resulted in being granted five US Patents, two Korean Patents, one Chinese patent, and others pending. Our chlorine sensor has overcome many limitations in the existing technologies for measuring total residual oxidant (TRO) found in virtually all types of water.