I. Working Principle of Sodium Hypochlorite Generator
A sodium hypochlorite generator is a device that generates a sodium hypochlorite solution by an electrochemical reaction of low-concentration saline solution through energized electrodes.
II. Basic Operation Procedures of Sodium Hypochlorite Generator
During operation, first, the power is turned on. Ordinary industrial salt ( approximately 0.35 yuan per kilogram) is added to the salt dissolving device to dissolve into a brine solution of about 10% . The valve is opened to allow the brine to pass through the filter and precipitate into the salt storage tank. Then, the automatic water mixing switch is activated, and the equipment automatically mixes the brine to a concentration of approximately 3.5% . Next, the valve is opened and the flow meter is adjusted, allowing the prepared brine to pass through a jacketed electrolytic cell composed of a set of anode and cathode tubes at the set flow rate. After the sodium hypochlorite generator is activated, the rectifier current switch is turned on, and the cooling water valve is opened simultaneously to cool the electrolytic cell. The sodium hypochlorite generator then begins operation. In this way, the entire equipment produces standard sodium hypochlorite liquid (concentration of approximately 1% ). Finally, the solution automatically flows into the storage tank for easy storage and subsequent addition.
Backwashing: After each shift, a backwash must be performed. During backwashing, first open the vent valve to drain the brine that has accumulated in the pipeline, then open the backwash vent and backwash inlet valves and flush for about 10 minutes. After that, open the vent valve to drain the accumulated water for the next use.
Acid washing: The generator needs to be acid washed once every 250 hours of cumulative operation . The acid washing cycle may be extended or shortened according to the water quality. During acid washing, first open all drain valves to drain the accumulated brine in the pipeline. Then open the acid inlet valve and the acid outlet valve until acid water flows out of the organic pipe of the acid outlet vent pipe. Then close the acid inlet valve and let the acid water soak in the electrode tube for 1-2 hours before draining the acid water. Then backwash once. Generally, the concentration of dilute hydrochloric acid is about 10% .
III. Precautions
① When working automatically, no special personnel are required to manage it. One salt addition can keep it working for ( 7-10 ) days. When the salt water is insufficient , it will automatically stop and alarm. The generator must be backwashed once when adding salt . It must be acid-washed once every month or so.
② During equipment operation, it is strictly forbidden to operate without cooling. If the unit experiences a water outage, the equipment must not be used.
③ Regularly check whether the power supply connectors are loose or overheating, and whether the filter screen in the high-level salt tank is clogged, and remove any blockages promptly.
④ Avoid smoking and open flames indoors as much as possible, maintain good ventilation, and assign part-time staff for management.
IV. The sterilization and virus-killing principle of sodium chlorate generators can be roughly divided into the following three modes of action:
Sodium hypochlorite generators primarily work by hydrolyzing hypochlorite to form hypochlorous acid, which then further decomposes to form nascent oxygen [O] . The extremely strong oxidizing properties of nascent oxygen denature proteins and other substances on bacteria and viruses, thus killing the pathogenic microorganisms. In fact, the principle of disinfection mainly relies on the generation of hypochlorous acid and the release of nascent oxygen .
According to chemical measurements, sodium hypochlorite generators with PPM concentrations almost completely hydrolyze into hypochlorous acid in water, achieving an efficiency exceeding 99.99% . The process can be simply represented by the following chemical equation:
NaClO + H₂O ＝ HClO + NaOH
HClO → HCl + [O]
Secondly, in the process of sterilization and virucidal action, sodium hypochlorite generators can not only act on cell walls and viral shells, but also, because hypochlorite molecules are small and uncharged, can penetrate into bacteria (viruses) and react with bacterial (virus) proteins, nucleic acids, enzymes, and other organic macromolecules to kill pathogenic microorganisms.
R-NH-R + HClO → R2NCl + H2O
Meanwhile, the chloride ions produced by hypochlorous acid can significantly alter the osmotic pressure of bacteria and viruses, causing their cells to lose activity and die.
Furthermore, sodium hypochlorite generators can also decompose trace amounts of pesticides remaining on agricultural products such as vegetables and fruits. Most pesticides are composed of organic matter, and the nascent oxygen released by the sodium hypochlorite generator can oxidize and decompose these substances. This undoubtedly has a significant positive impact on the development of modern agriculture and the fruit and vegetable packaging industry.
Furthermore, it is worth noting that, unlike chlorine dioxide and other disinfectants, the disinfectant produced by sodium hypochlorite generators does not produce free chlorine in water. Therefore, it is generally difficult to form carcinogenic substances that are harmful to human health due to the presence of free chlorine. Nor does it cause damage and poisoning to life when present in very small amounts (0.001 mg/m3) as ozone. Moreover, unlike the formation of hydrochloric acid after reacting with water, sodium hypochlorite generators do not cause serious corrosion to metal pipes.
