One. Physical cleaning methods
1. Stopping device
Slowly reduce the operating pressure of the pure water machine and gradually stop the equipment. Rapidly stopping the equipment will cause a sudden drop in pressure, which can create a water hammer effect, causing impact damage to pipes, pressure vessels, and membrane components.
2. Valve adjustment
First, fully open the concentrate water valve; then, close the water inlet valve. Next, fully open the output water valve (if the output water valve was closed after the system was shut down). If the output water valve is incorrectly closed, the membrane components at the rear of the pressure vessel may be mechanically damaged due to the output water back pressure.
3. Cleaning Operations
First, start the low-pressure cleaning pump; then, slowly open the water inlet valve while monitoring the concentrated water flow meter; adjust the water inlet valve until the flow and pressure are set to the design values; finally, after 10-15 minutes, slowly close the water inlet valve and stop the water pump.
II. Chemical Cleaning Methods
1. Citric acid solution
Under high or low pressure, continuously or cyclically wash the membrane with a 1-2% solution of citric acid, which effectively removes Fe(OH)3 contamination.
2. Concentrated Salt Solution
For membranes severely contaminated with colloidal matter, concentrated saline cleaning is an effective method. This is because the high concentration of saline reduces the interaction between the colloidal particles, promoting the aggregation of the colloidal matter into larger clumps.
3. Hydrogen peroxide solution
For example, diluting 0.5L of 30% H2O2 with 12L of deionized water, and then cleaning the RO membrane surface of the pure water machine, this method is particularly effective for removing organic contaminants.