The metal sintered filter element can be regenerated and cleaned by physical and chemical methods according to the pollution situation and the chemical properties of the pollutants combined with the physical and chemical properties of stainless steel.
The physical methods are mainly used: clean liquid backwash, clean gas backwash and ultrasonic cleaning.
The chemical method mainly adopts cleaning agents such as dilute acid, dilute acid, oxidant, surfactant, enzyme and so on.
The above methods can also be used interchangeably.
According to several common applications, the cleaning methods are as follows:
1. For decarburization and filtration in the pharmaceutical and chemical fields, back-flushing and back-flushing methods should be used frequently, combined with ultrasonic cleaning, to achieve the best results.
2. In the water production industry, because most of the trapped surface of the filter element is non-water-soluble salts and oxides, it is generally soaked in 5% nitric acid, and the cleaning effect can be achieved without ultrasonic cleaning.
3. Filtration of the original liquid should be combined with the chemical properties of the pollutants, and the following methods should be used for cleaning:
(a) Washing: Soak in 3-5% analytical pure sodium hydroxide solution for 30-60 minutes at a temperature of about 40 degrees, which is the best in an ultrasonic cleaner. After soaking, use filtered deionized water or water for injection to flush inside and outside to neutral, and measure the conductivity. Blow dry with pure air ≥ 0.4MPa pressure.
(b) Pickling: soak in 5% nitric acid solution for more than 8 hours at a temperature of about 40 degrees. Best in ultrasonic cleaners. After soaking, use filtered deionized water or water for injection to rinse internally and externally to neutral and lateral conductivity. Blow dry with pure air ≥ 0.4MPa pressure.
(c) Organic matter contamination can be cleaned with surfactants, and the cell debris contamination system combined with enzyme cleaning is more effective (food and beverage can be cleaned with high-concentration citric acid).
(d) The above methods can be used alone or in combination with each other. If possible, it is best to combine with an ultrasonic cleaning machine.
Note: Frequent online back-flushing (backflushing with pure compressed air or filtered stock solution or clean water for online cleaning) can reduce the number of times of cleaning with the above methods.