G4 Cardboard Frame Pre-Air Filter - High Efficiency, China Suppliers & Factory Offering Durable Solutions
🏢 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.
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Low Cost
One of the most economical filter types on the market, ideal for applications requiring regular bulk replacement.
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Lightweight & Easy Installation
The paper frame makes it very lightweight, easy to install and remove.
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Low Initial Air Resistance
Its loose structure ensures good air flow, places less demand on system fan pressure, and contributes to energy savings.
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Moderate Dust-Holding Capacity
The pleated design provides decent dust loading capacity, extending the replacement cycle compared to more basic mesh filters.
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Eco-Friendly
Main materials (paper frame, some filter media) are biodegradable or can be incinerated, resulting in a relatively lower environmental burden.
📋 Selection and Usage Note
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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: 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.
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4Installation Direction Pay attention to the airflow direction arrow on the filter and ensure correct installation, made according to specific conditions.
📊 Efficiency Grade Selection
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
🔹 What is a cardboard frame pre-filter and where is it commonly used?
A cardboard frame pre-filter is a primary-grade air filter featuring a kraft paperboard or corrugated paper frame with a pleated filter media. It is widely used in central air conditioning return air systems, fresh air unit intakes, office buildings, hotels, schools, industrial workshops, and computer room HVAC equipment.
🔹 What efficiency grades are available for cardboard frame pre-filters?
Cardboard frame pre-filters are most commonly available in G2, G3, and G4 efficiency grades. G2/G3 are suitable for general ventilation systems, while G4 provides higher filtration efficiency and is ideal for environments with higher cleanliness requirements or as a pre-filter upstream of medium-efficiency filters.
🔹 How often should a cardboard frame pre-filter be replaced?
Typical replacement cycles are every 1 to 3 months, depending on the dust concentration of the operating environment and the system's usage frequency. You should replace the filter sooner if the media appears visibly darkened, if airflow is noticeably reduced, or if the paper frame becomes damp, deformed, or damaged.
🔹 Can cardboard frame pre-filters be used in humid environments?
Cardboard frame pre-filters are not recommended for highly humid environments, as moisture can cause the paper frame to deform or lose structural integrity. In such conditions, it is advisable to use a primary filter with a metal (e.g., aluminum) frame, which offers better moisture resistance and a longer service life.
🔹 What filter media options are available for cardboard pre-filters?
The most common filter media option is metal mesh (aluminum or stainless steel), which is washable and reusable with good durability. While metal mesh media offers higher performance and reusability, it is generally more expensive than standard paper filter media.
🔹 Do you support custom sizes for cardboard frame pre-filters?
Yes, custom sizes are supported. It is important to accurately measure the installation space — including track dimensions or bolt hole positions — to ensure a precise fit and prevent air bypass (short-circuiting) through gaps around the filter frame. Please contact us with your specific size requirements.