Can chemical filters be washed and reused?

Direct answer: It is generally not recommended to continue using after washing. Unless the product description of the model clearly states that cleaning is allowed and the regeneration procedure and verification method are given.

Chemical filters are not the same thing as regular washable filters. Ordinary filters trap particles, and flushing with water can take away the dust on the surface. Chemical filters deal with gases and rely on media adsorption or reaction. Once the medium comes into contact with the target gas, the internal state has changed, and it is difficult to restore it to its original processing capacity by washing with water.

Distinguish between surface cleaning and filter material reuse

Let’s separate two things first.

Cleaning the equipment casing, frame or access door and cleaning the filter material itself are two different things. The outer casing can be wiped or cleaned according to maintenance requirements, but the filter material is the core functional part of the chemical filter and is generally replaced. On-site washing is not recommended.

Some products may have a replaceable filter element design. The internal filter material module is replaced instead of washing the old filter material and putting it back. Please refer to the specific structure the chemical filter product range . Description of

What problems may be caused by water washing?

The impact of water washing on chemical filters can be viewed from several aspects.

Media structure may change. Some chemical filter media are granular, some are impregnated carriers, and some are composite structures. Water washing may cause media swelling, hardening, loss or uneven distribution of impregnated ingredients. It looks like it's still there, but the processing power may have been reduced.

Effective capacity may decrease. The locations where the medium has been adsorbed or reacted may not be restored by washing with water. Some reaction products remain inside the medium and cannot be removed by washing with water. After washing, the air volume may recover a little, but the gas processing capacity may not return. For specific life span judgment, please refer to Discussion of how long chemical filters last .

Seals and frames may be damaged. During the washing process, the sealing gasket may deform, degumm, or absorb water and swell. The metal frame may be rusted. These changes can affect the installation seal, causing bypass. For specific bypass inspection, please refer to Discussion on how to check frame bypass after chemical filter installation .

Incomplete drying can leave hidden dangers. The internal structure of the chemical filter is complex, and the moisture in the pleats or filling layers is not easy to completely dry. Residual moisture may affect the state of the medium, and may also breed microorganisms or cause corrosion during operation.

Contaminants may migrate. During water washing, the components originally trapped on the medium may be washed out and enter the drainage or spread to the surrounding environment. If components with corrosive or biological risks are filtered, the treatment of washing wastewater also needs to be managed according to project requirements.

Under what circumstances can it be cleaned?

There is only one situation that can be considered: the product description clearly states that the model is allowed to be cleaned, and the cleaning method, drying conditions and re-inspection requirements are given.

Even so, you should follow the instructions and do not act on your own. After cleaning, the outlet concentration and sealing status need to be verified according to project requirements to confirm that the processing capacity still meets the target. For specific efficiency judgment, please refer to Discussion of the difference between initial efficiency and lifetime efficiency of chemical filters .

For most conventional chemical filters, it is more prudent to schedule replacement based on operating data and outlet concentration trends. For specific replacement criteria, please refer to Discussion on whether the chemical filter can be replaced based on the pressure difference .

How to deal with dust falling on the surface

If there is only dust on the surface, do not wash it directly with water.

First check whether the pre-filter section is normal. Many ash fallout problems result from failure of front-end particle filtration or the installation of bypasses. Dealing with front-end problems is more effective than washing the end filter material. For specific methods, please refer to Discussion on how to deal with dust falling on the surface of chemical filters .

Dust on the casing or frame can be cleaned with a dry cloth or vacuuming according to the maintenance instructions. It is not recommended to beat, blow or wash dust on the surface of the filter material because these operations may allow dust to enter the media or damage the filter material structure.

If the ash fall is accompanied by a decrease in air volume or an increase in outlet concentration, it is recommended to evaluate and replace the filter material instead of trying to clean it.

Project judgment example

The air volume of a chemical filter in a certain project dropped after running for a period of time. The operation and maintenance personnel took out the filter element, rinsed it with water, dried it and put it back. After reinstallation, the air volume recovered somewhat, but the outlet concentration was still high.

The investigation found that water washing caused some media to harden, the effective processing area decreased, and the sealing gasket was also deformed. After replacing the new filter element and checking the installation seal, the outlet concentration returned to normal.

Another project is just dust on the outer casing, and serious dust accumulation in the pre-filter section. After cleaning the pre-filter and replacing the front-end filter, the pressure difference and outlet concentration of the chemical filter returned to the normal range, and the filter material itself was not cleaned.

These two cases illustrate that the recovery of air volume does not equal the recovery of processing capacity. If there is dust on the surface, the front end must be checked first. involving When selecting a chemical filter product series , it is recommended that the maintenance requirements and replacement criteria be provided to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s maintenance and replacement packages

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 that require a maintenance plan, the target gas, operating data, filter material status and replacement requirements can be combined to assist in checking the maintenance and replacement methods.

Related products:Chemical filter product series、MAU box chemical filter、FFU comes with chemical filter . Provide usage conditions and maintenance requirements when enquiring, which will help confirm the appropriate solution. The specific selection is subject to the technical documents and test results confirmed by the project.