G4 Cardboard Frame Pre-Air Filter - High Efficiency Suppliers in China | Quality Factory Manufacturing
Application Area
- Return air sections of commercial and residential central air conditioning systems; pre-treatment for fresh air system intakes.
- Ventilation equipment in office buildings, shopping malls, hotels, and schools.
- Primary pre-filtration in industrial plants and production workshops.
- Air conditioning equipment in computer rooms and communication base stations.
- Household fresh air ventilators and air purifiers (as a pre-filter).
Filter Media Materials
The frame of a cardboard frame pre filter is typically made from high-quality kraft paperboard or high-strength corrugated paper. The selection of this material is carefully considered.
Low Cost
One of the most economical filter types on the market, ideal for applications requiring regular bulk replacement.
Lightweight & Easy Install
The paper frame makes it very lightweight, easy to install and remove.
Low Initial Air Resistance
Loose structure ensures good airflow, reducing fan pressure demands and contributing to energy savings.
Moderate Dust-Holding
Pleated design provides decent dust loading capacity, extending the replacement cycle versus basic mesh filters.
Eco-Friendly
Main materials (paper frame, filter media) are biodegradable or can be incinerated, with a lower environmental burden.
Metal Mesh Option
Aluminum or stainless steel mesh; washable and reusable with good durability. Higher cost, used where reusability is required.
Selection and Usage Notes
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1Size Matching: Accurately measure the installation space (track or bolt holes) to ensure a perfect fit and prevent air "short-circuiting" — unfiltered air bypassing the filter through gaps.
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2Environment Assessment: If the operating environment is very humid, strongly consider choosing a primary filter with a metal frame (e.g., aluminum). Although slightly more expensive, its stability and service life far exceed those of paper frames.
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3Regular Inspection and Replacement: Primary filters are consumables and must be inspected regularly. Replace promptly when:⚠ Replace when: The filter media appears visibly darkened and saturated with dust; increased air resistance leads to a significant reduction in airflow; the paper frame is damp, deformed, or damaged.
Typical replacement cycles are 1–3 months, depending on environmental dust concentration and usage frequency. -
4Installation Direction: Pay attention to the airflow direction arrow on the filter and ensure correct installation, made according to specific conditions.
Efficiency Grade Selection
| Grade | Description & Application |
|---|---|
| G2 / G3 | The most common grades, suitable for general ventilation systems. |
| G4 | Higher efficiency, capturing finer particles. Often used in places with slightly higher cleanliness requirements or as a pre-filter for medium-efficiency filters. |
Wind Speed Relationship Diagram
Product Parameters
Remarks: (1) Initial resistance tolerance of ±10% (2) Support customer size
Frequently Asked Questions
Q
What is a cardboard frame pre-filter and where is it commonly used?
A cardboard frame pre-filter is a primary-stage air filter with a frame made from kraft paperboard or corrugated paper and a filter media layer. It is widely used in return air sections of commercial and residential central air conditioning systems, fresh air system intakes, office buildings, shopping malls, hotels, schools, industrial plants, computer rooms, and household air purifiers.
Q
How often should a cardboard frame pre-filter be replaced?
Typical replacement cycles are 1 to 3 months, depending on environmental dust concentration and usage frequency. You should replace the filter when the media appears visibly darkened and saturated with dust, when airflow is noticeably reduced due to increased resistance, or when the paper frame becomes damp, deformed, or damaged.
Q
What is the difference between G2/G3 and G4 efficiency grades?
G2 and G3 are the most common grades and are suitable for general ventilation systems requiring standard particle capture. G4 offers higher filtration efficiency, capturing finer particles, and is often used in environments with higher cleanliness requirements or as a pre-filter stage before medium-efficiency filters to extend their service life.
Q
Can cardboard frame pre-filters be used in humid environments?
Cardboard frame pre-filters are not ideal for very humid environments, as moisture can cause the paper frame to warp, deform, or lose structural integrity. In such conditions, it is strongly recommended to choose a primary filter with a metal frame — such as aluminum — which offers far superior stability and a longer service life despite being slightly more expensive.
Q
Are cardboard frame pre-filters eco-friendly?
Yes. The main materials used — kraft paperboard frames and many types of filter media — are biodegradable or can be safely incinerated, resulting in a relatively low environmental burden compared to plastic-framed alternatives. This makes cardboard frame pre-filters a more environmentally responsible choice for high-frequency replacement applications.
Q
Do you support custom sizes for cardboard frame pre-filters?
Yes, custom sizes are supported to accommodate different installation requirements. It is important to accurately measure your installation space — including track dimensions or bolt hole positions — to ensure a perfect fit and avoid air short-circuiting, where unfiltered air bypasses the filter through gaps. Please contact us with your specific dimensions for a tailored solution.