Air Filter Manufacturer and HEPA Filter Provider

HOME

ABOUT US

Company Profile

PRODUCTS

🏭 Industry Application

⚡ Product Performance

🔧 Product Feature

EV Charging Stations

Filtration for Power Equipment

Cleanroom & Semiconductor

Ultra-High Cleanliness Filtration

Commercial HVAC

Central Air System Filtration

Data Centers

Precision Equipment Protection

Livestock & Farming

Farming Environment Purification

Spray Booths & Industrial Dust

Paint Mist & Dust Purification

View All Products →

EV Charging Stations Industry Application

Filtration for Power Equipment

Professional air filtration for EV charging devices, protecting against dust and sand ingress to ensure stable, reliable operation of charging piles and station infrastructure.

View Related Products →

Cleanroom & Semiconductor Industry Application

Ultra-High Cleanliness Filtration

Ultra-high efficiency filtration for semiconductor wafer fabs and precision electronics cleanrooms, capturing nano-scale particles to meet ISO Class 1–3 standards and maximize product yield.

View Related Products →

Commercial HVAC Industry Application

Central Air System Filtration

High-efficiency filtration for commercial building HVAC systems, improving indoor air quality, reducing energy consumption, and extending equipment service life.

View Related Products →

Data Centers Industry Application

Precision Equipment Protection

Precision air filtration for data centers, shielding servers and critical hardware from dust contamination to keep cooling systems running efficiently and reliably.

View Related Products →

Livestock & Farming Industry Application

Farming Environment Purification

Dedicated filtration systems for farms and livestock facilities — capturing dust, adsorbing ammonia, and inhibiting pathogen spread to improve animal health and overall productivity.

View Related Products →

Spray Booths & Industrial Dust Industry Application

Paint Mist & Dust Purification

Designed for spray booths and grinding workshops, efficiently capturing paint mist, metal dust, and wood chips to meet emission standards while protecting finished surface quality.

View Related Products →

Dust Collection Filters

Q: What is a bag filter?

A bag filter — also called a pocket filter — is a medium-efficiency filter whose media is stitched into three to eight pockets that hang in the airstream. The pockets give several square metres of media in one 592×592 frame, so the air passes slowly and the filter holds a large amount of dust before it has to be changed.

Q: What is the difference between F5 and F9?

They are steps on the same EN 779 ladder: F5 removes the coarse fraction, F7 is the usual general-purpose medium grade, and F9 is the highest medium grade used immediately upstream of a HEPA stage. Each step up costs more initial resistance, so F9 is only worth it where the stage behind it needs the protection.

Q: How many pockets do I need?

Enough to bring the face velocity down to what the duct and the fan are designed for. More pockets mean more media area, lower resistance and a longer service life, in the same frame opening — the constraint is usually the frame depth and the cost of the media.

Q: When should the filter be replaced?

When the pressure drop reaches the final resistance for the grade, which is around 400 to 450 Pa on this range, or when the airflow can no longer be held. Fit a differential pressure gauge and mark the change point at commissioning rather than guessing from the calendar.

Q: Can bag filters be custom sized?

Yes. The standard sizes cover the common holding frames, and custom sizes are made to the frame dimension, including non-standard depths. Send the frame drawing and the required grade.

Q: Which frame material should I choose?

Galvanised steel is the default for general HVAC and industrial duty, and aluminium alloy is used where weight matters or where a corrosive airstream would attack the zinc coating. Stainless steel frames are available for aggressive environments.

Q: Bag filter or cartridge filter?

Bag filters are cheaper per unit and easier to dispose of, and they are the normal choice for medium-efficiency duty in a ducted system. Cartridge filters hold more dust in a smaller volume and suit dust collectors with a pulse cleaning system, where the filter is cleaned in place rather than thrown away.

Q: Do you supply the media as well as the finished filter?

Yes. The polyester bag media roll, the high-dust-holding roll and the glass fibre roll are supplied with the same grades and colour coding as the finished pocket filters, for filter makers and for sites that assemble their own.

Bag filters are the workhorse of medium-efficiency filtration: F5 to F9 in EN 779, three to eight pockets in the same face size, and media areas from 2.12 m² to 5.68 m² depending on the grade. Whalesens builds the finished pocket filters and the media they are made from — the polyester bag media roll, the high-dust-holding roll and the glass fibre roll.

Because a pocket filter is a media area problem before it is a filter problem, the table below gives pocket count, media area and rated airflow for each grade. Pick the grade that protects the stage behind it, then take the pocket count that gives the face velocity your duct can carry.

Request a quote See all 8 products

Dust Collection Filters range

Selection table

Model	Filtration grade	Media	Pocket count	Media area	Initial resistance	Rated airflow
Fiberglass Bag Filter Media	F6, F7, F8	Weather-resistant glass fibre, non-woven
High Dust Holding Bag Filter Media Roll	F5, F6, F7, F8	Polypropylene blended with polyester and nylon, gradient needle-punched
Bag Air Filter Media Roll	G4, F5, F6, F7, F8, F9	Polyester (PET) fibre, carded and hot-air bonded
F8 Medium Efficiency Bag Filter	F8 (F9 available in the same frame)	Non-woven synthetic fibre, or glass fibre	3, 6, 8	2.80 – 5.68 m²	115 – 120 Pa	1,700 – 3,400 m³/h
F7 Medium Efficiency Bag Filter	F7 (F8, F9 available in the same frame)		3, 6, 8	2.80 – 5.68 m²	90 – 100 Pa	1,700 – 3,400 m³/h
F5 Medium Efficiency Bag Filter	F5 (F6, F7, F8, F9 available in the same frame)	Non-woven synthetic fibre, or glass fibre	3, 5, 6	2.12 – 4.28 m²	45 – 50 Pa	1,700 – 3,400 m³/h
F9 Medium Efficiency Bag Air Filter	F9 (F7 and F8 available in the same frame)		3, 6, 8	2.80 – 5.68 m²	125 – 130 Pa	1,700 – 3,400 m³/h
F6 Medium Efficiency Bag Filter	F6 (F5, F7, F8, F9 available in the same frame)	Special non-woven synthetic fibre, or glass fibre	3, 6, 8	2.12 – 5.68 m²	50 – 65 Pa	1,700 – 3,400 m³/h

How it compares

Bag vs pleated filter

A bag filter folds the media into pockets, so the same 592×592 frame carries several square metres of media at a low face velocity and takes a large dust load. A pleated panel is more compact and cheaper at the same grade, but it holds less dust and reaches its final resistance sooner in a dirty airstream.

Synthetic vs glass fibre media

Non-woven synthetic media is the general choice: stable in humid air, tolerant of repeated load cycles and available in every grade. Glass fibre media holds more dust in a thinner web and is used where the temperature or the dust load is beyond what the synthetic web will take.

Finished filter vs media roll

A finished pocket filter arrives assembled, sealed and ready to fit, which is what most end users want. The media rolls are for filter makers and for sites that assemble their own pockets, and they are supplied with the same grade and colour coding as the finished filters.

Where it is used

Metalworking and metallurgy

Workshop dust control and equipment protection in foundries, welding shops and machining halls, where the pockets carry a heavy metal dust load.

Metallurgy dust case →

Glass and mineral processing

Dust purification on glass and mineral product lines, where fine airborne dust has to be removed before it reaches the product surface.

Glass manufacturing case →

Power plants

Turbine hall, switch room and general ventilation filtration, including the pre-filter stages ahead of final filters.

Power plant case →

Paper mills

Process and ventilation air filtration in paper and board mills, where humid, fibrous dust is the normal duty.

Paper mill case →

FAQ

What is a bag filter?

A bag filter — also called a pocket filter — is a medium-efficiency filter whose media is stitched into three to eight pockets that hang in the airstream. The pockets give several square metres of media in one 592×592 frame, so the air passes slowly and the filter holds a large amount of dust before it has to be changed.

What is the difference between F5 and F9?

They are steps on the same EN 779 ladder: F5 removes the coarse fraction, F7 is the usual general-purpose medium grade, and F9 is the highest medium grade used immediately upstream of a HEPA stage. Each step up costs more initial resistance, so F9 is only worth it where the stage behind it needs the protection.

How many pockets do I need?

Enough to bring the face velocity down to what the duct and the fan are designed for. More pockets mean more media area, lower resistance and a longer service life, in the same frame opening — the constraint is usually the frame depth and the cost of the media.

When should the filter be replaced?

When the pressure drop reaches the final resistance for the grade, which is around 400 to 450 Pa on this range, or when the airflow can no longer be held. Fit a differential pressure gauge and mark the change point at commissioning rather than guessing from the calendar.

Can bag filters be custom sized?

Yes. The standard sizes cover the common holding frames, and custom sizes are made to the frame dimension, including non-standard depths. Send the frame drawing and the required grade.

Which frame material should I choose?

Galvanised steel is the default for general HVAC and industrial duty, and aluminium alloy is used where weight matters or where a corrosive airstream would attack the zinc coating. Stainless steel frames are available for aggressive environments.

Bag filter or cartridge filter?

Bag filters are cheaper per unit and easier to dispose of, and they are the normal choice for medium-efficiency duty in a ducted system. Cartridge filters hold more dust in a smaller volume and suit dust collectors with a pulse cleaning system, where the filter is cleaned in place rather than thrown away.

Do you supply the media as well as the finished filter?

Yes. The polyester bag media roll, the high-dust-holding roll and the glass fibre roll are supplied with the same grades and colour coding as the finished pocket filters, for filter makers and for sites that assemble their own.

Dust Collection Filters

Dust Collection Filters range

Fiberglass Bag Filter Media

High Dust Holding Bag Filter Media Roll

Bag Air Filter Media Roll

F8 Medium Efficiency Bag Filter

F7 Medium Efficiency Bag Filter

F5 Medium Efficiency Bag Filter

F9 Medium Efficiency Bag Air Filter

F6 Medium Efficiency Bag Filter

Selection table

How it compares

Bag vs pleated filter

Synthetic vs glass fibre media

Finished filter vs media roll

Where it is used

Metalworking and metallurgy

Glass and mineral processing

Power plants

Paper mills

FAQ

Further reading