How to determine the configuration when the thickness of the chemical filter is limited?

On the equipment side, in retrofit projects or in space-constrained filtration sections, one constraint is often encountered: there is not enough depth left for the chemical filter.

Conventional box-type or deep-bed structures cannot fit in, so only thin solutions can be considered. However, the thin solution brings a problem: as the thickness decreases, less media can be installed, and the processing capacity and service life may be affected. It doesn’t mean you can use it just by putting it in. You need to find a balance between space, air volume, media capacity and maintenance methods. For specific structural forms, please refer to Discussion of the common product forms of chemical filters .

Record the space boundaries first

Before determining the configuration, first understand the actual amount of available space, rather than just looking at 'not enough depth'.

Effective installation depth. Is it the distance from the inner opening of the frame to the rear structural member, or is it the net depth after deducting gaskets, hold-downs and installation tolerances? These two values ​​are different. Mark the benchmark when measuring to avoid treating theoretical space as usable space.

Framework and interface occupation. The gasket needs compression space, the compression piece needs operating space, and the outer frame itself also has thickness. These are deducted from the total depth.

Replace the path. After the filter element is installed, can it be taken out? Some locations are just deep enough for installation, but there is no room to pull out when replacing. This is especially important for device-side applications. For specific measurement methods, please refer to Discussion of what dimensions should be covered for chemical filter retrofit field measurements .

adjacent structures. Are there any pipes, cables, or structural parts near the filter section that will affect installation and maintenance? Although these factors do not directly occupy the depth of the filter, they will affect the feasibility of the solution.

Sort out these boundary conditions clearly before entering into configuration comparison. Don’t think that the solution is feasible just because a thin product is just the right size.

Compare the actual configuration, not just the thickness

When the thickness is limited, 'thin' means different things for different products.

Filter media type and filling amount. Under the same thickness, different media have different filling densities and effective capacities. Some media have a higher adsorption capacity per unit volume and can maintain a certain lifespan with a thin structure; some media require a larger filling volume to achieve the effect, and a thin solution may not be enough.

Effective filter area. Thin products may have a smaller effective area. Under the same air volume, as the wind speed increases, the contact time between the gas and the medium is shortened, and the treatment effect may be reduced. For the specific relationship between surface wind speed and efficiency, please refer to Discussion on how to calculate the removal efficiency of chemical filters .

resistance characteristics. Thin products may have different resistance than deep bed products. Whether the system fan can withstand the new resistance needs to be calculated based on the actual working point. For specific methods, please refer to Discussion of how much the added resistance of the chemical filter will increase the fan's electricity consumption .

Capacity and replacement cycle. Reduced thickness means less media, possibly lower capacity, and potentially shorter replacement cycles. Can the project tolerate more frequent replacements? Will maintenance costs rise? These should be compared with operational requirements. For specific life assessment, please refer to Discussion of how long chemical filters last .

Therefore, the complete data under the same air volume, the same target gas and the same outlet requirements must be used when comparing, not just the thickness.

Adjust system division of labor when necessary

If the thin solution is limited in capacity or resistance, consider adjusting the system division of labor.

Increase effective area. Where depth is limited, this can be compensated for by increasing the size of the windward surface. If the installation location permits, choose a solution with a larger area and a slightly thinner thickness to arrange more filtering areas within a limited depth.

Change processing location. If the depth of the filter section cannot be changed, you can evaluate moving the chemical filter section to other locations, such as the fresh air section, return air section, or outside the equipment. Available space and airflow conditions vary from location to location. Please refer to the specific installation location selection. which air handling systems are appropriate for chemical filters to be installed in . Discussion of

Local protection replaces global treatment. If the overall treatment solution does not have enough space, you can evaluate whether to only partially protect key areas or sensitive equipment. The local solution has a smaller processing air volume, and the filter section size may be easier to meet. Device-side applications such as An FFU equipped with a chemical filter or an ultra-thin EFU equipped with a chemical filter layer can be evaluated in this way.

Increase preprocessing to reduce load. If the inlet concentration is high, a pretreatment section can be set up at the front end to reduce the load entering the chemical filtration section, thereby reducing the need for media capacity. Please refer to the specific division of labor Discussion on the division of labor between chemical filters and primary filters .

Each adjustment plan requires verification of the air volume and target gas effects, and unconditional equivalence cannot be guaranteed. involving For MAU box-type chemical filter systems , the total system resistance and air volume in each area need to be rechecked after adjustment.

Post-installation verification

After the thin solution is installed, the actual performance needs to be verified.

Air volume measurement. Confirm that the air volume passing through the filter section is within the design range and does not decrease significantly due to increased resistance.

Outlet concentration detection. Detect the target gas outlet concentration according to project requirements to confirm that the protection objectives are met. You can't judge the effect just by 'it's installed'.

Resistance monitoring. Record the initial pressure difference and track changes during operation. If the pressure difference rises quickly, it may be that the media filling amount is insufficient or the inlet load is too high.

Replacement cycle assessment. After running for a period of time, judge whether the actual replacement cycle is acceptable based on the outlet trend and cumulative load. If the replacement is too frequent, you need to go back and evaluate whether the plan needs to be adjusted. For specific detection methods, please refer to Discussion of sampling points for chemical filter performance verification .

Project judgment example

The depth of the filter section reserved inside a certain equipment is only 60 mm, and conventional chemical filters cannot be placed there.

The preliminary plan selects a thin product with a thickness of about 50 mm. However, calculations found that under the target air volume, the passing wind speed of this product is relatively high, the media capacity is limited, the replacement cycle is expected to be less than three months, and the maintenance cost is high.

Adjustment plan: Evaluate the equipment structure and find that there is room for horizontal space. Switching to a thin structure with a larger windward surface and a thickness of about 55 mm increases the effective filtration area while keeping the depth basically unchanged. After adjustment, the wind speed is reduced, the capacity is increased, and the replacement cycle is expected to be extended to an acceptable range. After installation, measure the air volume and outlet concentration to confirm that the requirements are met.

This case illustrates that when thickness is limited, capacity and resistance can be balanced by adjusting area and structure. involving When selecting a chemical filter product series , it is recommended that space constraints, target gases and maintenance requirements be provided to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s thin solution package

The core of the chemical filter configuration with limited thickness is to balance air volume, capacity, resistance and maintenance conditions in a limited space.

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 projects with limited space, the installation depth, target gas, air volume and maintenance requirements can be combined to assist in checking thin structures, filtration areas and media configurations. 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 available space, target gas, and system conditions when requesting a quote can help identify a suitable low-profile solution. The specific selection is subject to the technical documents and test results confirmed by the project.