Filter Cartridge Cleaning Principle And Method
1. Cleaning principle:
a. Use the physical washing effect to wash away the particles.
More effective for rigid particles (filter cake clogging).
b. Diatomaceous earth
Effective on the membrane surface (membrane holes are also very narrow).
2: Utilizing the physical and chemical action of cleaning agents(Wetting, emulsification, hydrolysis, dissolution, dispersion, peptization, chelation, etc.)
The filter element can be cleaned to minimize the physical blockage of the membrane, and its effect can be achieved by selecting a reasonable cleaning agent and cleaning method;
Filter cleaning can be divided into forward cleaning and reverse cleaning; reverse cleaning is not recommended, especially for terminal filters.
The reason is that after reverse cleaning, impurities in the cleaning agent or cleaning water will remain on the downstream end of the membrane, which will cause pollution to the next batch of products.
3. Forward cleaning
The cleaning method of the cleaning agent or the washing water from the upstream to the downstream of the membrane can be completed with a pressure slightly greater than the filtration product.
4. Reverse cleaning
a. Cleaning agent, the water used to prepare the cleaning agent and the washing water must be absolutely pure.
b. The pressure should be strictly implemented according to the parameters given in the product manual.
5. When selecting a cleaning agent, the following factors must be considered:
No.1 Type of blockage
Many liquids are complex mixtures, more than one cleaning agent may be required, multiple types of blockages may be required, and multiple cleaning steps may be required.
No.2 Types of membrane and system materials
Cleaning agents must be chemically compatible with membrane and system materials.
No.3 application requirements
The cleaning agent should be chemically compatible with the material being filtered or no residue.
Several typical cleaners and their main effects and applications.
Aqueous NaOH solutions with a concentration of 0.1N-1.0N are compatible with many types of membranes and can remove blockages caused by most organics and biopolymers.
HNO 3, H 3 PO 3, HCl are common acids used to remove inorganic substances, such as calcium salts and magnesium salts. HNO 3 and H 3 PO 3 can be used to clean the surface of stainless steel. HCL will corrode most stainless steel. It is recommended to use citric acid to remove the blockage caused by iron compounds.
Most effective with minimal damage to membranes.
Surfactants and detergents are recommended for the initial cleaning of membranes and systems to remove contaminants and some products.
C12 can oxidatively degrade blocked proteins and organics. When NaOH and surfactants are not effective, it is recommended to use C12 as a cleaning agent, or as the second step of cleaning after using NaOH and surfactants.
C12 is derived from NaOC1 or Ca (OC1)2. Effective chlorine concentration should be used in the range of 100-300ppm. (Equal to 300-800ppm NaOC1). Chlorine as a cleaning agent and depyrogenizer has the strongest activity at PH10-11. NaOC1 can also be used as a disinfectant, but it should be used at a low concentration (20-40ppm) when used for disinfection. It forms HOC1 at PH6-8 and has the largest bactericidal activity.
Since chlorine is consumed during the cleaning process, the concentration of chlorine should be regularly monitored during the cleaning process and NaOC1 should be added to maintain the recommended concentration.
e. hydrogen peroxide
It is a useful disinfectant, but it does not effectively degrade protein and is not recommended for cleaning.
Enzymes are occasionally used for special cleaning applications but are not recommended for frequent use.