Frequent equipment alarms and dust accumulation at vents? A guide to selecting filter cotton and dustproof paper
The cooling system, air intake system, and control cabinet protection of equipment almost entirely rely on filter materials. There are five common filter materials on the market: polyurethane (PU) filter cotton, fiber cotton (carbon-free/carbonized), non-woven fabric, fiberglass, and dustproof paper. Our factory offers customized products in all of the above materials.
One: Polyurethane (PU) Filter Cotton Good elasticity, oil resistance, and washable, suitable for high humidity or oil mist environments, such as CNC machine tools and spray painting workshops. However, its flame retardancy is poor, so use with caution in high-temperature environments. Applications and types include: air conditioner fan dustproof filter cotton, air purifier high-efficiency filter cotton, fresh air system pre-filter cotton, range hood oil sludge interception filter cotton, industrial dust washable filter cotton, cabinet ventilation dustproof filter cotton, aquarium biochemical culture filter cotton, custom thickness/porosity filter cotton, etc.
Second: Fiber cotton is divided into carbon-free and carbon-added types. Carbon-free cotton has stable filtration efficiency and is suitable for general ventilation; carbon-added cotton has an additional activated carbon layer, which can absorb odors and harmful gases, and is used in places requiring air purification such as electronics factories and laboratories, but its dust holding capacity is relatively low, and the replacement frequency is higher. This includes high-efficiency filter cotton for dust and impurity removal, air conditioner fan-specific filter cotton, air purifier pre-filter cotton, fresh air system breathable filter cotton, range hood oil sludge filter cotton, equipment dustproof and antibacterial filter cotton, etc. Custom sizes/pore sizes of filter cotton can be customized, and it can be cut to fit specific equipment.
Third: Non-woven fabric (non-woven cloth) has low cost and low resistance, and is often used for pre-filtering, such as air conditioner return air vents and equipment air inlets, but its precision is limited and it is not suitable for precision equipment. Types include non-woven fabrics for automotive interior sound absorption, industrial equipment dustproofing, furniture lining cushioning, appliance casing protection, pipe insulation, and packaging shock absorption, etc.
Four: Glass fiber filtration offers high precision (up to HEPA level), high temperature and corrosion resistance, suitable for high-temperature flue gas treatment and cleanroom high-efficiency filtration. However, it is brittle and cannot be bent, requiring careful installation. Dustproof paper has uniform micropores and extremely low resistance, suitable as a breather for equipment control cabinets or as the final dustproof layer before packaging. However, it has lower strength and cannot be exposed to moisture. It has a wide range of types and applications, such as high-temperature resistant glass fiber insulation cotton, equipment and pipe insulation glass fiber felt, industrial furnace and kiln fireproof glass fiber cloth, electrical insulation glass fiber tape, high-temperature filtering glass fiber cotton, sound insulation and noise reduction glass fiber board, etc.
When selecting filter materials, a comprehensive judgment should be made based on the temperature, humidity, dust type, allowable resistance, and replacement cost of the operating environment. The three core indicators determining the filtration effect are filtration precision, initial resistance, and dust holding capacity. Regarding filtration precision, G3 grade filters capture particles larger than 10 micrometers for general ventilation; G4 grade filters capture particles larger than 5 micrometers for general equipment cooling; and F5 grade filters capture particles larger than 1 micrometer for precision instruments. Many users blindly choose high-precision filter cotton, resulting in excessive resistance, insufficient airflow, and ultimately worse heat dissipation.
The three core indicators determining filtration effectiveness are filtration precision, initial resistance, and dust holding capacity. Regarding filtration precision, G3 grade filters capture particles larger than 10 micrometers for general ventilation; G4 grade filters capture particles larger than 5 micrometers for general equipment cooling; and F5 grade filters capture particles larger than 1 micrometer for precision instruments. Many users blindly choose high-precision filter cotton, resulting in excessive resistance, insufficient airflow, and ultimately worse heat dissipation.
Initial resistance directly affects fan energy consumption. For example, a 2.2 kW fan using filter cotton with an initial resistance of 30 Pa consumes approximately 1.8 kW; switching to 80 Pa filter cotton could increase energy consumption to 2.5 kW, resulting in several thousand yuan more in electricity bills per year. Zhongke Foam's customized filter cotton can minimize initial resistance while maintaining filtration accuracy by adjusting fiber fineness, density, and thickness.
Dust holding capacity refers to the amount of dust the filter cotton can hold before it is scrapped. Ordinary non-woven filter cotton has a dust holding capacity of approximately 300-500 grams per square meter. Zhongke Foam uses synthetic fiber cotton with a gradient density structure, with coarser fibers on the windward side and finer fibers on the leeward side, achieving a dust holding capacity of over 1500 grams per square meter. This extends the replacement cycle from one month to three months, significantly reducing labor and downtime losses.
In the filtration system, the dustproof paper (non-woven filter paper) is equally important. It is not ordinary paper, but a non-woven material made of polyester fibers through thermal bonding or chemical bonding. Its surface has uniform micropores, an initial resistance of only 10-20 Pa, and high stiffness, making it suitable as a standalone filter media for frame filters. Zhongke Foam can provide die-cut dustproof paper sheets, with or without adhesive backing, produced according to drawings.
Typical applications of dustproof paper include cleanroom air vents (as pre-filter protection for HEPA filters), equipment control cabinet breathers (balancing air pressure and blocking dust), and the final dustproof layer before packaging (installed at the front of an air blower to ensure compressed air cleanliness). Different types of equipment require different filtration combinations: large fans and air conditioning units are recommended to use G3 pre-filter cotton plus G4 dustproof paper; laser cutting and welding equipment are recommended to use a two-stage filtration system of F5 synthetic fiber cotton plus G4 dustproof paper; outdoor control cabinets and distribution boxes are recommended to use aluminum foil rubber and plastic sponge plus dustproof paper.
Many users buy standard-sized filter cotton (e.g., 1 meter wide x 20 meter long rolls) and then cut them themselves with a utility knife, which presents three problems: inaccurate dimensions, resulting in rough edges and gaps that allow dust to "shortcut" into the equipment; significant waste, as the standard width may not be an integer multiple of the equipment's air vent width, leading to 20%-30% waste of scrap material; and lack of functional composites, as ordinary filter cotton lacks adhesive backing, flame retardant properties, and oil and water resistance.
Our factory's customization service can solve these problems: We use molds to precisely cut out the shape according to the equipment's air vent drawings, ensuring smooth, burr-free edges and a tight fit during installation; we apply adhesive backing to one side of the filter cotton, allowing direct application to the inside of the air inlet after peeling off the release paper; flame-retardant treatment reaches UL94 V-0 or V-2 ratings, suitable for electrical cabinets with fire protection requirements; for CNC oil mist environments or humid outdoor environments, we can apply oleophobic or hydrophobic coatings to the filter cotton; we can also pre-heat-press filter cotton of different precision grades together.
If your equipment frequently alarms, has poor heat dissipation, or excessive internal dust, we recommend disassembling the air inlet to check if the filter cotton is blackened and clogged, whether the airflow at the outlet is significantly reduced, and verifying the filtration level recommended in the equipment manual. Our factory produces according to drawings; you only need to provide the drawings or dimensions, and we will arrange processing.
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