What dimensions should be covered by on-site measurements for chemical filtration retrofits?

In a renovation project, if the on-site measurement step is done poorly, problems will arise in subsequent model selection, ordering, and installation.

A common situation is: you only measure the length, width and height of the old filter element, and then use this size to find the chemical filter section. As a result, even after it was installed, the pressing piece could not be pressed in place, the sealing surface could not meet, or the filter could not be taken out when changing the filter element. The problem is not with the product, but with the narrow measurement range.

The on-site measurement of chemical filtration modification must at least cover the installation frame, sealing surface, compression structure, removal path, air duct interface and support load-bearing. Each item is explained below.

Define the measurement object first

Before measuring, first confirm 'what to measure'.

The size of the old filter element can be used as a reference, but it cannot be directly used as the new product specification. The old filter element may have been deformed, aged, or was not a standard part in the first place. The size of the installation frame is what the chemical filter section will ultimately match.

When measuring, it is recommended to record the data of the old filter element and the installation frame at the same time to verify each other. If the old filter element has been removed, at least measure the installation frame correctly.

For specific matching methods, please refer to Discussion of how chemical filter sizes match existing filter frames .

Installation frame clear opening

This is the most basic set of dimensions.

The length, width and diagonal of the inner opening of the filter frame must be measured separately. The diagonal line is used to determine whether the installation frame is deformed. If the lengths of the two diagonals are inconsistent, it means that the frame has parallelogram deformation, and the chemical filter section may not be pressed tightly when it is installed.

The measurement location should be clearly marked, whether it is the net size of the inner opening or the outer frame size. In some projects, the size of the outer frame is reported to the supplier as the size of the inner opening. As a result, the product is too large and cannot be installed.

The depth of the mounting frame must also be measured. The available distance from the mounting surface to the rear structural member determines how thick the chemical filter section can be made. Please refer to the configuration when the specific thickness is limited. Discussion of how to determine configuration when chemical filter thickness is limited .

Installation depth and sealing contact surface

Depth and sealing surface are related.

The installation depth is not just the thickness of the filter element itself. It is also necessary to deduct the compression space required by the sealing gasket or liquid tank, the space occupied by the pressing parts, and the thickness of the frame structure. These add up to the real usable installation depth.

The position and width of the sealing contact surface are measured separately. The sealing gasket or liquid tank of the chemical filtration section needs to correspond to this contact surface. If the contact surface is on the air inlet side, the sealing structure of the filter element must also be on the corresponding side. Please refer to the specific directions to confirm Discussion on whether the chemical filter gasket should face the inlet or outlet side .

Whether the contact surface is flat or not should also be recorded. Locations with solder bumps, old seal remnants or corrosion pits should be noted in the measurement record.

Compression structure and disassembly and assembly path

These two items are often overlooked but directly impact installation and maintenance.

The location, quantity, and type of hold-down parts must be measured. Can the compression point cover the entire length of the sealing surface? Are there any compression points at the corners and midpoints of the long sides? If the original compression structure is not suitable, the modification plan should explain how to deal with it.

The disassembly and assembly path needs to be simulated once. After the filter element is installed, can it be taken out? What pipes, cables, and structural parts are there in the removal direction? When the internal space of the equipment is tight, replacing the filter element may require disassembling other components first. These operating procedures should be documented in the measurement record.

For the feasibility of the disassembly and assembly path, please refer to How to check the frame bypass after installation of the chemical filter on the installation interface inspection ideas, confirm in advance.

Air duct interface and support load-bearing

The chemical filter section is not only installed in the frame, but also connected to the air duct and box.

The size, flange position, and connection method of the air duct interface must be measured. If the new filter section changes the direction of the air duct, the interface size may need to be adjusted.

Support bear important confirmation. The chemical filter section may weigh more than the original filter section. Can the original frame, ceiling or support structure withstand it? If not, you need to consider reinforcement or choose a lighter solution in your renovation plan.

The location of peripheral equipment should also be recorded. Are there any equipment, pipelines, or bridges near the filter section that would affect installation or maintenance? This information can help suppliers determine the feasibility of the solution.

Operating parameters and airflow direction

In addition to dimensions, operating parameters must also be recorded on site.

The actual air volume, fan gear, and pressure difference in each section must be measured. Design parameters and actual conditions after many years of operation may differ. For specific air volume balancing methods, please refer to whether chemical filtration modification requires re-doing the air volume balance . Discuss

The air flow direction should be confirmed along the actual air path. The air path inside the equipment may have twists and turns, so you cannot judge based on the direction of the old filter element alone. For specific confirmation methods, please refer to Chemical filter airflow arrow unclear discussion on how to confirm.

If the target gas is not clear, air sampling can also be arranged. For specific methods, please refer to whether to do air sampling before choosing a chemical filter . Discuss

Closed loop of records and drawings

After the measurement is completed, the data is organized into usable records.

Suggestions include: clear opening size of the installation frame, available depth, sealing surface position and width, distribution of pressing parts, disassembly and assembly path instructions, air duct interface size, support conditions, and operating parameters.

It is best to accompany the measurement data with photos and diagrams to indicate the measurement benchmark. After the supplier obtains this information, it can determine whether the size and structure of the chemical filtration section are feasible. When dimensions or sealing methods are changed, records should be updated and reconfirmed.

For the overall assessment conditions before transformation, please refer to Discussion of what conditions should be evaluated first before adding a chemical filter to an existing clean room . For the impact of transformation on pressure difference, please refer to Discussion of how chemical filter modification can avoid affecting room pressure differential .

Project judgment example

For a certain renovation project, the length, width, and height of the old filter element were only measured, and the chemical filtration section was ordered based on this size.

After the product arrived, it was discovered that there was a raised solder joint at the inner opening of the mounting frame and the sealing surface was uneven. After the chemical filter section is installed, the position cannot be pressed tightly and a bypass appears in the frame. At the same time, the thickness of the filter element is slightly larger than that of the old one, and it interferes with the upper pipeline when it is taken out, making maintenance inconvenient.

Adjustment method: Make additional measurements on the clear opening and sealing surface of the installation frame, trim the solder joints, and adjust the position of the pressing parts; at the same time, measure the disassembly and assembly path to confirm the removal angle. After adjustment, the filter section is installed in place and the sealing inspection is qualified.

This case illustrates: On-site measurement cannot only measure the shape of the old filter element, but also covers the installation frame, sealing surface, compression structure and disassembly and assembly paths. involving When selecting a chemical filter product series , it is recommended to provide measurement records, operating conditions and target gases to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s transformation measurement package

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 retrofit projects, on-site measurement data, installation frame structure, operating conditions and target gases can be combined to assist in checking the chemical filtration section size, sealing method and structural configuration.

Related products:Chemical filter product series、MAU box chemical filter、FFU comes with chemical filter . Providing measurement records, system conditions and modification requirements when inquiring can help identify suitable solutions. The specific selection is subject to the technical documents and test results confirmed by the project.