What is a Residual chlorine meter?

The Residual chlorine meter measures the amount of free-type active chlorine and chloramine that remain in the water after being treated with chlorine-based chemicals at a water purification plant. It is a device for measuring. Residual chlorine is a measurement of the amount of chlorine remaining 30 minutes after adding a chlorine contract agent used to prevent the spread of water-borne infectious diseases into water. Displayed in ppm. Residual chlorine has a strong bactericidal power, but it almost disappears in the drain pipe. The presence of some residual chlorine can maintain its disinfecting effect. However, if there is an excessive amount of residual chlorine, the smell of chlorine is strong and it corrodes metals. It is also well known as a cause of carcinogenic substances, so It must be measured accurately for water quality control, routine inspection and maintenance.

Application of Residual chlorine meter

Residual chlorine meters are mainly used in public facilities such as buildings, condominiums, apartment buildings, schools, hospitals, public halls, foods, and beverage factories. It is used in cooking facilities, swimming pools, elevated water tanks, hot springs, and other places where water quality control is required. The usage example is as follows. Water quality management when drinking water is used as a raw material in the food process Pumping stations and water distribution stations on the water pipe network All process management of waterworks Management of factory / industrial water equipment (cooling water / drinking water) Water quality management for large boilers Deodorizing equipment for human waste, sewage treatment plants, deodorizing equipment for meat factories, etc. Principle of Residual Chlorine Meter Residual chlorine can be measured by using reagents such as iodine titration method, colorimetric DPD method, and DPD absorptiometry. There is a reagent-free measurement method called the polarograph method, in which a weak current is passed through a sensor that uses precious metal electrodes to measure electrical conductivity. In the iodine titration method, a potassium iodide solution is added under the condition of pH 4 or less to replace free chlorine and bound chlorine with iodine, and then This is a reagent-type measurement method that measures total residual chlorine. The reagent form is used for process control in the water purification plant. Colorimetric DPD method and DPD absorptiometry When a DPD indicator is added to a sample, it is oxidized by chlorine and develops a magenta color. While comparing the degree of color development Measurement can be performed by reading the numerical value engraved on the colorimetric board. This is the easiest method that can be easily performed at the measurement site. A residual chlorine meter using the polarographic method is used between a micro-rotating platinum electrode immersed in a sample and a quiescent platinum electrode with a relatively large area. When a voltage of -0.4V is applied to cause concentration polarization on the surface of the rotating platinum electrode, a diffusion current corresponding to the amount of residual chlorine flows. The conductivity is expressed numerically.

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