The working principle and application scenarios of filter cartridges

1、 The core working principle of the filter element

The filter element achieves the separation and purification of impurities in fluids (liquids/gases) through mechanisms such as physical interception, adsorption, chemical reactions, or membrane separation. According to the differences in material and structure, the main working principles can be divided into the following categories:

1. Physical filtering (mechanical interception)

-Principle: Use the pore size of the filter material to intercept particle impurities. When the particle size is larger than the pore size, it is blocked.

-Typical filter material:

-Fiber type: non-woven fabric, glass fiber (with uniform pores, used for air/liquid coarse filtration).

-Metal mesh/sintered material: stainless steel mesh, metal sintered filter element (high strength, high pressure resistance, used for filtering hydraulic oil and chemical liquids).

-Application scenarios:

-The car air filter element filters dust in the air with an accuracy of 5-50 μ m.

-The hydraulic system filter intercepts metal debris in the oil (accuracy 1-20 μ m).

2. Adsorption filtration

-Principle: By utilizing the surface adsorption capacity of porous materials, organic matter, pigments, odors, or heavy metal ions in fluids can be captured.

-Typical filter material:

-Activated carbon: granular activated carbon (GAC) or compressed activated carbon rod (CTO), with a large surface area and strong adsorption capacity.

-Molecular sieve: such as zeolite, selectively adsorbs specific molecules (such as water molecules and carbon dioxide) through pore size.

-Application scenarios:

-Removing residual chlorine, pesticide residues, and color and odor in drinking water treatment.

-Adsorption of volatile organic compounds (VOCs) in industrial waste gas treatment.

3. Chemical filtration (chemical reaction)

-Principle: The filter material undergoes a chemical reaction with impurities in the fluid, converting harmful substances into harmless substances or precipitating them.

-Typical filter material:

-Ion exchange resin: removes calcium, magnesium ions (softened water) or heavy metals (such as lead and copper) from water through ion exchange.

-Catalytic filter element: such as filter materials containing catalysts, which decompose harmful components in fluids (such as the three-way catalytic filter element in automobile exhaust purification).

-Application scenarios:

-Soften hard water in boiler water treatment to prevent scale formation.

-Removing heavy metal ions in laboratory wastewater treatment.

4. Membrane separation filtration

-Principle: By utilizing the selective permeability of semi permeable membranes, molecules or ions of different particle sizes can be separated.

-Typical filter material:

-Microfiltration membrane (MF): accuracy of 0.1-10 μ m, capable of intercepting bacteria, colloids, etc. (such as filtration in mineral water production lines).

-Reverse osmosis membrane (RO): with an accuracy of 0.0001 μ m, it removes inorganic salts, viruses, and heat sources (such as preparing direct drinking water from household water purifiers).

-Application scenarios:

-Ultra pure water preparation in the semiconductor industry (with a filtration accuracy of nanometer level).

-Aseptic filtration in the pharmaceutical industry (such as injection sterilization, using 0.22 μ m microporous membrane).

2、 Typical application scenarios of filter cartridges

Filter cartridges are widely used in industries, people's livelihoods, healthcare, environmental protection, and other fields. The following is a classification by industry:

1. Industrial manufacturing field

-Mechanical processing and equipment maintenance:

-Hydraulic system: Metal sintered filter element filters particles and impurities in hydraulic oil to prevent pump and valve wear (accuracy 1-10 μ m).

-Lubrication system: The wound filter element filters dust and metal debris from lubricating oil, extending the service life of equipment such as machine tools and wind power equipment.

-Chemical and petroleum industries:

-Filter solid impurities in corrosive liquids such as sulfuric acid and caustic soda using polypropylene (PP) or polytetrafluoroethylene (PTFE) filter cartridges.

-During crude oil extraction, drilling fluid is filtered to remove sediment and rock debris (coarse filtration of large particles with an accuracy of 50-200 μ m).

-Food and beverage processing:

-Filter pulp residue and microorganisms in syrup and juice (such as foldable filter cartridges with an accuracy of 1-5 μ m).

-Alcohol clarification filtration, using diatomaceous earth filter or membrane filter to remove suspended solids and colloids.

2. Environmental protection and water treatment field

-Municipal water supply treatment:

-Pre treatment stage: PP cotton filter element removes sediment and rust (accuracy 5-50 μ m).

-Deep processing stage: Activated carbon filter cartridge adsorbs organic matter, RO membrane removes heavy metals and bacteria (such as upgrading and renovating water plants).

-Wastewater treatment:

-Ultrafiltration membrane filter (UF) separates large molecular organic matter and colloids from wastewater for reuse of reclaimed water.

-In industrial wastewater treatment, ion exchange resin filters remove heavy metal ions (such as nickel and chromium in electroplating wastewater).

-Air purification:

-High temperature resistant glass fiber filters are used in industrial dust removal equipment to filter dust from boiler exhaust (such as power plant desulfurization and denitrification systems).

-The spraying workshop filters paint mist particles using polyester fiber folding filter cartridges (precision 0.3-1 μ m).

3. In the field of automobiles and transportation

-Engine system:

-Air filter: Non woven filter filters dust in the intake air to protect the cylinder (such as car and truck engines, with an accuracy of 5-20 μ m).

-Fuel filter element: filters moisture and particles in gasoline/diesel to prevent nozzle blockage (accuracy 1-10 μ m).

-New energy vehicles:

-The battery coolant filter element filters impurities such as silicon powder and metal ions to ensure the safety of battery thermal management systems (such as electric vehicle coolant circulation systems).

-Ship and Aviation:

-Marine diesel engine fuel filtration uses high-precision filter elements (accuracy ≤ 5 μ m) to prevent fuel impurities from damaging the engine.

4. Medical and laboratory fields

-Pharmaceutical industry:

-The sterile filter cartridge (0.22 μ m polyvinylidene fluoride membrane) filters microorganisms in the injection solution, meeting GMP sterile requirements.

-Filtration of bioreactor fermentation broth, separation of bacterial cells and products (such as deep filtration in monoclonal antibody production).

-Medical devices:

-Hemodialysis machines use activated carbon filters to adsorb toxins and odors from dialysate.

-The operating room air purification system uses HEPA filters (filtration efficiency ≥ 99.97% @ 0.3 μ m) to maintain a sterile environment.

-Laboratory analysis:

-The ultrapure water system is equipped with ion exchange resin filter and UV sterilization filter to prepare ultrapure water with a resistivity of ≥ 18.2M Ω· cm.

5. Livelihood and consumption fields

-Household water purifier:

-Multi stage filter cartridge combination: PP cotton (coarse filtration)+activated carbon (adsorption)+RO membrane (fine filtration), removes residual chlorine, heavy metals, and bacteria from water.

-Air purifier:

-HEPA filters PM2.5, while activated carbon filters adsorb harmful gases such as formaldehyde (such as in home and office settings).

-Kitchen appliances:

-Filter the filter elements of coffee machine and soybean milk machine to filter the residue and improve the taste of drinks (such as stainless steel filter elements).

4、 Key points of selection and maintenance

1. Selection core logic:

-Select materials based on fluid properties (liquid/gas, corrosiveness, viscosity).

-Determine the filtration accuracy and principle based on the characteristics of pollutants (particle size, concentration, composition).

-Select filter structure (such as folding or sintering type) based on system flow rate, pressure, and installation space.

2. Maintenance points:

-Replacement cycle: through pressure difference monitoring (such as replacement when the pressure difference is ≥ 0.3MPa) or usage time (such as replacing the car filter every 10000 kilometers).

-Cleaning method: The filter element (such as ceramic filter element) can be cleaned by backwashing or ultrasonic cleaning, and the activated carbon filter element cannot be regenerated and needs to be replaced directly.

-Environmental protection treatment: Filter cartridges containing oil or chemical pollutants should be treated as hazardous waste, while ordinary filter cartridges should be discarded according to garbage classification.

summarize

The filter element achieves fluid purification through diversified working principles, and its application scenarios cover multiple fields such as industrial production, environmental protection, and people's health. When selecting, it is necessary to accurately match the filtration requirements and filter performance, while paying attention to maintenance to ensure long-term efficient operation. With the development of material technology, high-precision, long-life, and easy to maintain filter cartridges (such as composite membrane filter cartridges and reusable metal filter cartridges) are becoming the preferred solution in various industries.