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The Thesvin Bag Filter is a pocket-style air filter that installs in HVAC systems, cleanroom fresh-air units and industrial supply-air ducts, capturing coarse to fine particulate in G4 to F9 efficiency grades. It is built for facility engineers, OEM equipment makers and contractors who need predictable fitment, sealed airflow and stable efficiency across commercial buildings, electronics plants, pharmaceutical facilities and data centres. Thesvin manufactures the filter in Zhongshan, Guangdong, China, with frame and bag dimensions matched to your host unit or duct.
Fitment comes first in a bag filter. The filter is located by its outer frame, which slides into a holding frame or filter track in the air-handling unit, and the bag section extends downstream into the duct or plenum. Thesvin supplies the frame in aluminium or galvanised steel, so the outer dimensions, frame depth and bag length define how the filter seats against the host structure. When the frame is square and the dimensions match the track, the filter sits flush, the bags hang without touching each other, and bypass air around the frame is reduced.
Standard frame sizes follow common imperial footprints: 594 × 594 mm (24" × 24"), 594 × 492 mm (24" × 20") and 289 × 594 mm (12" × 24"), all with a 534 mm (21") depth. The bag count is selected with the frame width: 6, 8 or 10 bags for the 24" × 24" size, 6 or 8 bags for 24" × 20", and 3 or 4 bags for 12" × 24". A 381 mm (15") depth option is also available. If your unit uses a non-standard opening, Thesvin builds to your drawing, so the bag filter drops into the existing track without adapters. The rated operating face velocity is 2.5 m/s, which is the reference point for matching the filter to your airflow and pressure budget.
The filter media is high-throughput non-woven fibre or flame-retardant fibreglass, formed into pockets that hold dust across a large surface area. G4 pre-filter grades capture coarse dust and protect downstream coils and filters; M5 and M6 medium-efficiency grades capture finer particles in commercial air systems; F7, F8 and F9 grades serve cleanroom fresh-air and industrial supply-air applications where finer particulate control is required. The pocket geometry gives high dust holding capacity, which lowers energy use between change-outs and extends service intervals in dusty environments.
Typical installations include central air-conditioning pre-filtration in commercial buildings, cleanroom fresh-air systems, and HVAC filtration in electronics, pharmaceutical and coating plants. The filter also works as a pre-filter ahead of higher-efficiency final filters, protecting them from coarse dust and reducing later maintenance cost. Because the bag structure is self-supporting under normal airflow, the filter holds its shape at the rated 2.5 m/s and resists damage at higher face velocities when the system is balanced correctly.
| Item | Detail |
|---|---|
| Filter grade | G4 / M5 / M6 / F7 / F8 / F9 (pre-filter to medium efficiency) |
| Media | High-throughput non-woven fibre or flame-retardant fibreglass |
| Frame material | Aluminium or galvanised steel |
| Rated operating face velocity | 2.5 m/s |
| Standard sizes (W × H × D) | 594 × 594 × 534 mm (24"×24"×21") – commonly 6 / 8 / 10 bags 594 × 492 × 534 mm (24"×20"×21") – commonly 6 / 8 bags 289 × 594 × 534 mm (12"×24"×21") – commonly 3 / 4 bags Other depths such as 381 mm (15") available |
| Core applications | Central air-conditioning pre-filtration in commercial buildings, cleanroom fresh-air systems, HVAC filtration in electronics, pharmaceutical and coating plants |
| Customisation (OEM) | Non-standard sizes and bag counts fully supported, backed by 20 years of manufacturing experience and a CNAS testing centre |
Thesvin holds IATF 16949 certification, obtained in 2024, and applies IQC, IPQC and OQC controls to keep frame dimensions and bag geometry consistent from batch to batch. A CNAS-accredited laboratory issues test reports for filter efficiency, dust holding capacity and resistance, so the data behind each grade can be checked against your specification. The 50,000 m² production facility includes six clean workshops totalling 20,000 m², and the company operates under ISO 9001, ISO 14001 and ISO 45001 management systems. Products meet REACH and RoHS requirements, with compliance documents available on request. Multiple automated lines support monthly output in the millions of pieces, which helps protect delivery schedules for large projects and peak seasons.
To get a quotation, send the device or vehicle model, the frame size or a drawing (a photo of the old filter label works), the airflow or water flow, the operating conditions and the quantity you need. Thesvin's team will confirm the grade, bag count and frame material, and reply with price and lead time. Start your inquiry here: contact Thesvin.
Fitment depends on the frame dimensions and the bag length. Thesvin offers standard frames of 594 × 594 mm, 594 × 492 mm and 289 × 594 mm, all 534 mm deep, with a 381 mm depth option. If your track or holding frame is non-standard, Thesvin can build to your drawing so the filter seats correctly.
Yes. A photo of the old filter label or the old filter itself gives Thesvin the frame size, bag count and grade. The team can then match or improve the specification and confirm the replacement dimensions before quoting.
The Thesvin Bag Filter is available in G4, M5, M6, F7, F8 and F9 grades, covering pre-filter to medium-efficiency duties. Selection depends on the target efficiency and the dust load in your HVAC or cleanroom system.
G4 is typically used for coarse pre-filtration ahead of coils or final filters, while F7–F9 grades suit cleanroom fresh-air and fine industrial supply air. Share your airflow and dust conditions, and Thesvin will recommend a grade that balances efficiency and service life.
Yes. Thesvin supports non-standard sizes and bag counts, as well as frame material and media selection, based on 20 years of manufacturing experience and a CNAS testing centre. Send your drawing or sample for a custom evaluation.
Yes. Standard sizes can be supplied as samples, and custom samples are quoted case by case. Each sample can be accompanied by test data from the CNAS laboratory so you can verify fitment and performance before placing a bulk order.
MOQ and lead time depend on the specification and order volume. Send your required size, grade and quantity through the contact page, and Thesvin will confirm the minimum order and delivery schedule for your project.
Replacement depends on dust load and operating hours. As a guide, inspect the filter at regular intervals and change it when resistance rises or the bags show visible loading. The high dust holding capacity of the pocket design helps extend service intervals under normal HVAC conditions.