Which air handling systems are suitable for chemical filters to be installed in?

Where to install the chemical filter is not a question of 'which location is better'.

The location depends on where the contamination is coming from and where the airflow is going. If external pollution comes in from the fresh air, the filter section should be on the fresh air path; if internal releases persist, return air or circulation filtration must be considered; there are sensitive areas inside the equipment, which may require local protection. If installed in the wrong position, the airflow will not pass through the filter section, and it will be useless no matter how correctly the media is selected. For specific configuration methods, please refer to the chemical filter product range . Description of

Fresh air system controls external loads

Outdoor air is a major source of pollution in many projects.

Industrial emissions, traffic exhaust, and surrounding facilities may bring acid gases, organic matter, or other components. These gases enter the factory with the fresh air vents. If not treated, they will directly enter the clean area or inside the equipment.

The fresh air chemical filtration section is usually located in the air handling unit , possibly after pre-filtration, before or after the surface cooler. Where to place it specifically depends on the temperature and humidity conditions and the applicable scope of the filter material. The humidity behind the surface cooler is high and droplets may be entrained. Some chemical media are sensitive to moisture and need to be evaluated. The temperature in front of the surface cooler is high and there may be unfiltered dust, so pre-filtration protection is very important. For specific layout, please refer to Description of MAU Box Chemical Filter .

The location of the air inlet and the surrounding environment should be investigated together. If the new air outlet is close to the pollution source, you can consider adjusting the location or adding pretreatment. The filter cannot compensate for all unreasonable inlet conditions, but a reasonable inlet location can reduce the filter load. For specific entrance evaluation methods, please refer to The factory is close to the source of pollution, and the discussion on how to match the relocation of the air inlet with chemical filtration is discussed.

Seasonal changes also need to be considered. The pollution load may be different in different wind directions and seasons. Consider the most unfavorable conditions when designing, or reserve room for adjustment.

Circulatory system handles internal releases

Indoor equipment and materials may continuously release gaseous pollutants, which cannot be treated by fresh air alone.

Return air or FFU loop filtration can reduce the impact of internal releases. When the circulating air passes through the filter section, the target gas is adsorbed or reacted by the medium, and the concentration gradually decreases. This method is suitable for dealing with low-concentration, sustained-release pollution.

But it cannot replace local exhaust. If there is a strong release source at a certain workstation, priority should be given to setting up exhaust at the source to draw away the pollutants before they spread. Circulating filtration deals with pollution that has already entered the air, and is not as efficient as source control.

When areas share return air, attention should also be paid to cross-contamination. Gas from one area may enter another area through return air. At this time, it is necessary to evaluate the return air zoning, pressure difference relationship and filter configuration to avoid the spread of contamination.

FFU matching chemical filter is a common local circulation solution, suitable for equipment ends or local areas. The air volume, resistance and interface between the filter section and the unit need to be confirmed together during the planning stage. For specific configuration, please refer to Instructions for chemical filters provided with FFU .

The device side emphasizes local matching

The microenvironment inside the equipment has more specific requirements for chemical filtration.

The space inside the equipment cover is limited , and the size and resistance of the filter must match the equipment structure. Some devices can only accommodate filter segments in specific locations, and some require ultra-thin or custom construction.

Make sure the contaminated airflow passes through the filter section. The airflow path inside the equipment may be complex and blocked by mechanical arms, cables, and transmission parts. If the airflow bypasses the filter section, or the source of pollution is downstream of the filter section, the filtration effect will be compromised. Device-side applications such as The EFU supporting chemical filter solution needs to be evaluated together with the equipment structure.

Small filter elements also need proper airflow coverage and effective sealing. Small size filters cannot ignore sealing and installation requirements just because of their small size. Frame bypass and filter element displacement will affect the actual processing effect.

The replacement path must be confirmed during the design stage. The interior of the equipment is compact, and replacing the filter element may involve disassembling other components. Maintenance access and operating spaces need to be considered during the planning phase.

Common requirements for different locations

No matter where it is installed, there are several conditions in common.

The air volume must match. The air volume passing through the filter section must comply with the applicable conditions of the filter material. If the air volume is too high, the contact time is insufficient; if the air volume is too low, the processing capacity is insufficient.

The seal must be reliable. The frame bypass will allow untreated air to bypass the filter material, and the outlet concentration will naturally not decrease. The sealing inspection after installation cannot be omitted.

The system residual pressure must be sufficient. Adding new filter segments increases resistance. If the original fan margin is insufficient, the fan may need to be adjusted or the system optimized. For specific accounting methods, please refer to Discussion of how much the added resistance of the chemical filter will increase the fan's electricity consumption .

Maintenance space must be reserved. The replacement of chemical filters is based on gas processing capacity consumption, and the replacement cycle may be different from that of particle filters. The installation location should be convenient for inspection and replacement.

The temperature and humidity must meet the applicable conditions of the filter material. High humidity, condensation or high temperatures may affect the condition of the media. When selecting, confirm the suitability of the filter material in the target environment.

Project judgment example

There is pollution both in the outside air of a factory and inside the equipment.

There are industrial emissions near the fresh air inlet, bringing acidic gases; materials are released inside the equipment, producing organic vapors. The two sources are in different locations and should be handled differently.

Plan: Add a chemical filtration section for acidic gases in the fresh air section to reduce the load entering the factory; configure local circulation filtration for organic vapor at the equipment end to handle internal releases. The media, air volume and maintenance methods of the two filters are confirmed separately, and the total system resistance and pressure difference in each area are uniformly checked.

This case illustrates: Different sources require processing at different locations, and one terminal filter element cannot be required to bear the entire load. involving The selection of chemical filter product series can be checked based on specific application scenarios.

Key points for selection and acceptance inspection

About Aili Industrial’s air treatment packages

The location of the chemical filter depends on the source of contamination and the air path. If this part of information is clarified during the planning stage, subsequent selection and debugging will be much smoother.

Aili Industrial has independent manufacturing capabilities in filters, motors, fans, control systems and sheet metal processing, and can provide chemical filter product series and supporting air supply equipment. For fresh air systems, circulation systems or equipment-side applications, it can help check the location and configuration of the filter section based on the target gas, air volume, installation space and environmental conditions. When the filter is matched with MAU, FFU, EFU and other equipment, the resistance, interface and maintenance methods can be confirmed uniformly.

Related products:Chemical filter product series、MAU box chemical filter、FFU comes with chemical filter . Providing contamination sources, air paths, system conditions and maintenance requirements when requesting a quote will help identify appropriate installation locations and configuration options. The specific design is subject to the technical documents and site conditions confirmed by the project.