Fine Air Filters

Areas of application of fine air filters

Fine air filters are used in multistep filters of plenum and plenum exhaust ventilation units or air-conditioning systems to absorb small contaminating particles of various nature over 1 μm (micron).

Below are the examples of natural contaminants captured by fine filters:

• Medium and fine atmospheric dust
• Natural aerosols
• Plant pollen
• Fluff
• Dust mites
• Mushroom spores
• Large bacteria
• etc.

Below are the examples of anthropogenic air contaminants captured by fine filters:

• Highly dispersed carbon black
• Grinding dust
• Flour dust
• Cupola furnace dust
• Open-hearth furnace, metal sublimation
• Oily, alkaline, acid aerosols (“fogs”)
• Suspensions of polymer powder paints
• Welding fumes
• Aerosols resulting from soldering
• etc.

Where fine air filters are used:

• As the second and third cleaning steps (after-treatment) of intake air from the street in the ventilation and air conditioning systems of household, office and social premises: in housing properties, high-rise buildings, hospitals, health resorts, hotels, shopping centres, museums, etc.
• In industrial ventilation units for final air treatment in the premises with high demands to hygiene of the surrounding space: food manufacturing, meat and dairy factories, electronics, laboratories, mushroom growing facilities, etc.
• To clean the air in the working areas from production, chemical, biological aerosol contaminants and smoke
• As a filtering element for complex air-cleaning devices of compressor and gas turbine units

Types of fine air filters

In order to effectively clean the inlet air from fine suspensions, the filters of the relevant cleaning class of the following designs are used:

• Pocket filters (М5-F9)
• Compact filters (М6-F9): flat, W-shaped

Classification of fine air filters

By their effectiveness and average dust holding capacity, fine filters are divided into the following classes

The final pressure drop for the filters of classes М5-F9 is 450 Pa.

Design of fine air filters

Pocket filters (M5-M6 and F7-F9) are commonly used for fine cleaning of the inlet air in multistep plenum and plenum and exhaust ventilation units.

They are installed in the second and third stages of filtration after preliminary rough cleaning (G2-G4).

A pocket filter is a set of filtering sack pockets sewn from synthetic fibrous cloth and fixed in a light metal frame.

A compact filter of W-shape (also used in Air Filtering and Conditioning Systems (AFCS)) is a filter pack made of pleated fibre paper that is laid in W-shape in the plastic case of the required form.

The pleating of the filtering material in combination with W-shape laying allows making the product relatively small in size with multi-fold increase of the filtering surface. This results in a manifold increase of the dust holding capacity and prolongs the service life of this filter.

What materials are used

The filtering materials for the fine air filters are:

• Meltblown – synthetic nonwoven fabric made of polypropylene fibres with Meltblown technology. Used to produce pocket air filters for medium and fine cleaning.
• Combined SMS material (spunbond – meltblown – spunbond) – synthetic nonwoven three-layer electrostatically charged filtering material of propylene and polyester fibres. Used to produce effective pocket filters.
• Pleated paper made of fine fibre glass (filtering fibre glass). Used in the production of compact filters.

The listed modern filtering materials preserve their filtering properties at 100% humidity of the ambient air, and both at low (below -30) and high (up to +50 and higher) temperatures.

How often do you need to replace fine filters?

The frequency of fine filters’ replacement in the ventilation systems largely depends on the extent of pollution of the inlet air.

The filter’s condition is controlled by measuring its resistance to the airflow. Upon the achievement of the recommended final resistance (450 Pa), the fine filter shall be replaced.

The replacement of fine filters can be carried out according to a schedule:

• It is recommended to replace pocket filter 2-4 times a year
• Compact filters – 1-2 times a year

It is important to remember that the regeneration of the used filters is impossible. A dirty filter shall always be replaced with a new one.

Ultrafine Filters

The final stage of processing of the air space cleaning in the premises of high hygiene demands is achieved by High Efficiency Particulate Arrestance (HEPA) filters of H10 class or higher.

Such filters capture the smallest contaminants from the airflow with the size below 1.0-0.3 μm with the effectiveness from 85% to 99.9% or more.

HEPA-filters are used in different laboratories, operating rooms, sterile medical areas and other clean premises with the regulated level of cleanness (ISO class).

Before the air is fed to a HEPA-filter, it is subject to compulsory preliminary rough and fine cleaning with the relevant class filters.

You can read more about the design and principles of work of HEPA-filters produced by PHAUF in the following material: HEPA air filters supplied directly by manufacturer

Advantages of HEPA filters by PHAUF

Modern air filters for ventilation systems of PHAUF brand are manufactured by Research and Production Company MICROSISTEMA LLC as a part of imports phase-out program.

The production facilities are located in the Special Economic Zone of Technical and Implementation Type ISTOK. This allows the manufacturer to secure special terms, minimize tax load and lower to the maximum extent the price of the products for the end consumer.

Advantages of PHAUF air filters:

• High-tech production process
• Latest brands of the filtering materials
• European-level quality
• Attractive pricing
• Customized designs

PHAUF technical specialists will develop and produce the air filters of any size, design and cleaning class according to the customer’s individual preferences.