How to Acid Clean a Sodium Hypochlorite Generator
Acid cleaning is a routine maintenance procedure that helps remove mineral scale from the electrolysis cell and restore operating efficiency. Although the exact procedure may vary depending on the equipment design, most sodium hypochlorite generators follow a similar cleaning process.
Allow the electrolysis cell to cool before starting maintenance. As a general practice, cleaning should only begin after the cell temperature has fallen below approximately 30°C (86°F). Always wear appropriate personal protective equipment and use the acid concentration recommended by the equipment manufacturer.
First, switch off the electrolysis power supply and change the control system from automatic operation to manual mode.
Close the feed and product outlet valves, then open the drain valve and completely empty the electrolysis cell. After draining, flush the cell with clean water for about five to ten minutes to remove any remaining sodium hypochlorite solution and salt deposits. Continue rinsing until the discharge water is clear and no yellowish chlorine solution remains.
Once the initial rinse is complete, drain the cell again before starting the acid cleaning cycle.
Next, circulate the cleaning solution through the closed cleaning loop between the acid tank and the electrolysis cell. For light to moderate scale buildup, a circulation time of approximately 20 to 40 minutes is generally sufficient. During this process, small bubbles are usually visible inside the cell. This is a normal reaction as mineral deposits dissolve. When bubbling gradually stops, most of the scale has typically been removed.
After cleaning, stop the circulation pump and allow the acid solution to drain completely back into the acid tank. Confirm that no cleaning solution remains inside the electrolysis cell.
The cell should then be rinsed thoroughly with clean water for at least 20 minutes. Before restarting the equipment, check that the rinse water has returned to a near-neutral pH, typically between 6.5 and 8.5. If the water remains acidic, continue rinsing. Residual acid may increase electrode corrosion and could release chlorine gas when electrolysis resumes.
Finally, verify that all cleaning and drain valves have been returned to their normal operating positions. Refill the electrolysis cell according to the standard operating procedure, switch the controller back to automatic mode, and restore the power supply. After restarting, observe the equipment for several minutes to confirm that voltage, current, and chlorine production have returned to normal and that there are no leaks or abnormal odors.
Regular acid cleaning is a simple but important preventive maintenance practice. Performing this procedure before heavy scale develops helps maintain stable chlorine production, improve energy efficiency, and extend the service life of the electrolysis system.
Note: The acid cleaning procedure described in this article is intended as a general reference. Actual maintenance steps may vary depending on the equipment model and system configuration. Always follow the operation and maintenance manual provided by your equipment manufacturer before performing any maintenance.
