
A separator pleated rigid box filter is a medium-efficiency air filter built as a self-supporting box: pleated media is held apart by corrugated separators inside an aluminium or galvanised…
FILTER MEDIA / ROLLS · SHEETS · DIE-CUT

A separator pleated rigid box filter is a medium-efficiency air filter built as a self-supporting box: pleated media is held apart by corrugated separators inside an aluminium or galvanised steel frame. Oltaven builds these filters in G4, M5, M6, F7, F8 and F9 grades from non-woven fibre or high-precision glass fibre, so they capture coarse and fine dust ahead of final-stage units. They suit air handling units, cleanroom pre-filtration, paint shops and high-airflow industrial exhaust, and are supplied as finished filters rather than loose media.
The media sets the ceiling on what a filter can do; the finished build decides how much of that ceiling you actually reach. A sheet of glass fibre may test well in a flat sample, but once it is pleated, spaced, framed and sealed, the same sheet can deliver different efficiency, resistance and dust holding capacity. That is why Oltaven sells the assembled box, not the roll.
Pleating packs a large media area into a shallow box. More pleats mean more surface for air to pass through, which usually lowers resistance at a given airflow and raises the dust the filter can hold before it reaches final resistance. But pleats must stay open. If they collapse together under airflow, the effective area drops and resistance climbs. Corrugated separators keep the pleats apart and give the pack its rigidity, which is why this design holds shape in high-airflow ducts and resists deformation and rupture.
Framing and sealing turn the pleat pack into a filter. The frame carries the pack, holds its dimensions and lets it sit squarely in a holding frame without bypass. Sealing closes the gap between pack and frame so air cannot slip past the media. A well-formed filter is one where media, separator, frame and seal work as a single part; a poorly formed one leaks or deforms, and its rated efficiency means little in service.
Grade comes from media choice. Non-woven fibre covers the coarser G4 to M6 range; high-precision glass fibre carries the finer F7 to F9 grades. The pleat pack and seal preserve that grade by preventing bypass.
Resistance depends on media, pleat density and open frontal area. Deep pleats and open separators keep velocity through the media low. The rated operating face velocity of these filters is 2.5 m/s, matching high-airflow ventilation systems.
Dust holding capacity grows with media area and depth. The deep-pleat, large-area construction gives a high dust load before final resistance is reached, protecting downstream equipment.
These filters are used as pre-filters ahead of 100-class cleanrooms in pharmaceutical and electronics plants, protecting final-stage units. They sit in the intake section of commercial air handling units, in paint-shop dust removal, and in high-velocity industrial exhaust openings. Other uses include data centres, energy storage facilities, metal smelting and machinery manufacturing, where medium-efficiency filtration protects people, processes and equipment.
| Item | Detail |
|---|---|
| Product name | Separator pleated rigid box filter |
| Efficiency grades | G4 / M5 / M6 / F7 / F8 / F9 |
| Media | Non-woven fibre or high-precision glass fibre |
| Frame and separators | Aluminium or galvanised steel frame with corrugated separators |
| Rated operating face velocity | 2.5 m/s |
| Typical applications | Pre-filtration for 100-class cleanrooms in pharmaceutical and electronics plants; intake sections of commercial AHU systems; paint-shop dust removal; high-velocity industrial exhaust |
| Common sizes (W × H × D) | 24×24×21 in (594 × 594 × 534 mm); 24×20×21 in (594 × 492 × 534 mm); 24×24×15 in (594 × 594 × 381 mm); 12×24×21 in (289 × 594 × 534 mm) |
| OEM/ODM | Custom sizes and non-standard frames supported; produced in a 50,000 m² plant with a CNAS testing laboratory and ISO 9001/14001/45001 and IATF 16949 certification |
Oltaven is an OEM/ODM filter manufacturer with more than 20 years of development and production experience and over 1,000 filtration solutions developed to date. The plant covers 50,000 m² in Zhongshan, Guangdong, China, including six cleanrooms totalling 20,000 m² where filters are assembled. A CNAS-accredited laboratory tests efficiency, dust holding capacity and resistance and issues reports. The company holds IATF 16949 (obtained in 2024) plus ISO 9001, ISO 14001 and ISO 45001, and products meet REACH and RoHS requirements with compliance documents available. Multiple automated lines support output of millions of pieces per month, and IQC, IPQC and OQC checks run through production.
To quote accurately, tell us the device or vehicle model, the size or drawing, the airflow or water flow, the operating conditions and the quantity you need. Send these details through our contact page and our team will respond with a specification and quotation. We welcome long-term OEM/ODM partnerships.
Same-size filters can differ because resistance depends on pleat count, media type and how open the pleats stay. Corrugated separators keep pleats apart, preserving media area and lowering resistance at the rated 2.5 m/s face velocity.
It starts with your requirements: device model, size or drawing, airflow, operating conditions and quantity. Oltaven then confirms grade and construction options and quotes. Sample development typically takes 7–15 days, with standard samples available faster.
Grades range from G4 to F9. Coarser G4–M6 grades suit general ventilation and pre-filtration; F7–F9 glass fibre grades suit finer protection ahead of final-stage units in cleanrooms, pharmaceutical and electronics plants. Share your target and conditions for a recommendation.
Yes. Custom sizes and non-standard frames are supported, along with media grade, frame material, logo and packaging customisation. Oltaven has developed over 1,000 filtration solutions and produces in a 50,000 m² plant in Zhongshan, Guangdong, China.
Standard specifications typically have an MOQ of 50–100 pieces; custom specifications are confirmed case by case. Standard items ship in 15–20 days, custom orders typically in 25–35 days, and large orders receive a precise schedule.
Yes. Standard samples are available quickly; custom samples take 7–15 days and come with CNAS lab reports covering efficiency, initial resistance and dust holding capacity. Send your details through the contact page for a quotation.
Replacement depends on site air quality, running hours and the final resistance you set. Monitor pressure drop and change the filter when it reaches your final-resistance limit, which protects downstream equipment and keeps energy use in check.
Filters are assembled in six cleanrooms totalling 20,000 m², and IQC, IPQC and OQC checks run through production. The CNAS-accredited laboratory tests efficiency, dust holding capacity and resistance. Contact us to discuss your requirements.