Can old equipment still undergo chemical filtration modification without drawings?

Direct answer: You can evaluate, but you can’t skip on-site verification.

For many pieces of equipment that have been in operation for more than ten years, the original drawings can no longer be found. The equipment manufacturer may have switched production or gone bankrupt, and the maintenance personnel have changed several batches, leaving only a few photos or handwritten records. Now when it comes to adding a chemical filtration section, the first reaction is often 'it can't be done without drawings'.

Drawings are indeed important, but they are not the only basis. On-site measurements, operational surveys and prototype verification can reconstruct the critical information required for retrofits. The premise is that you can't just guess based on experience because you 'have no drawings', and you can't place an order directly just because 'it looks similar'.

Reconstruct necessary dimensional information

Without drawings, the first step is to re-measure the dimensions.

Mounting openings and clear openings. Measure the inner opening size, available depth, and flange position of the installation frame of the existing filter section. These are the interfaces that the chemical filtration section will fit into. For specific measurement methods, please refer to Discussion of what dimensions should be covered in chemical filtration retrofit field measurements .

Support and access access. Measure the mounting frame's support structure, holddown locations, access door openings, and removal paths. Some locations are large enough for installation, but cannot be dismantled, making maintenance after renovation difficult. Please refer to the specific maintenance space. Discussion of how chemical filter sizes match existing filter frames .

Old filter reference. If the old filter element is still there, measure its dimensions, gasket position, and airflow direction. However, it should be noted that the old filter element may have been deformed or aged, and the deformed size cannot be directly used as new product specifications. The actual measured dimensions of the installation frame should prevail.

Take photos and record. Take photos when measuring and mark the location and size benchmarks. On-site photos can help suppliers understand the actual structure and reduce back-and-forth confirmations. Please refer to the specific arrival inspection Discussion of what appearance and labels to check before installing a chemical filter .

Confirm airflow and device status

Size is only the first step. You also need to figure out how the airflow will flow and whether the equipment can withstand it.

Actual wind direction and volume. Investigate the airflow direction, actual air volume and operating gear of the existing system. The label of old equipment may say the design air volume, but after many years of operation, the fan performance, air duct resistance and filter section status may all change. Actual measurement data should prevail. For specific air volume balance, please refer to whether chemical filtration modification requires re-doing the air volume balance . Discuss

Fan operating point. Record the fan model, speed, current and air volume. If the original fan capacity is insufficient, the air volume may decrease after adding a chemical filter section. 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 .

Pressure difference in the filter section. Record the differential pressure and operating time of the existing filter section. If the existing filter element is heavily dusted and the pressure difference is high, the total resistance of the system after modification may exceed expectations.

Structural load-bearing. The frame and supports of older equipment may be rusted or warped. The chemical filter section may be heavier than the original filter section, and it is necessary to confirm whether the support structure can bear it. For specific inspection methods, please refer to Discussion on how to check frame bypass after chemical filter installation .

Solve unconfirmed items first

Before the transformation, list the 'unclear' items and confirm them one by one.

Unknown weight. If the frame load-bearing capacity cannot be determined, local reinforcement may be required or a lighter filter section solution may be selected. Please refer to the specific thickness restriction plan. Discussion of how to determine configuration when chemical filter thickness is limited .

Internal interference. In some locations where the internal structure is not visible from the outside, inspection holes or the use of an endoscope may be required. Just because you 'can't see it' doesn't mean there's no problem.

Fan performance. If the fan nameplate is lost, the current, speed and air volume can be measured, and the working point can be inferred based on the fan curve. If necessary, consult the original fan manufacturer or alternative manufacturer.

Conditions that cannot be confirmed should be clarified before design. Write uncertain items into the transformation plan and agree on verification methods. For specific evaluation conditions, please refer to Discussion of what conditions should be evaluated first before adding a chemical filter to an existing clean room .

Sample adaptation and trial

For projects without drawings, sample verification is especially important.

Make samples. Based on the on-site measurement data, first make one or a small number of chemical filter section samples. Prototypes are used to verify dimensions, interfaces, sealing and installation feasibility.

On-site fitting. Install the sample into the existing installation frame and check whether it can be installed in place, whether the seal can be pressed tightly, and whether the disassembly and assembly path is smooth. For specific installation inspection, please refer to Discussion on how to check frame bypass after chemical filter installation .

Run verification. After trial installation, measure the air volume, pressure difference and outlet concentration to confirm that the transformation goals are met. If the target gas is not clear, air sampling can be done first. For specific sampling methods, please refer to whether to do air sampling before choosing a chemical filter . Discuss

Batch freezing. After the prototype is verified, the dimensions, interfaces and material configurations are frozen before mass production is arranged. Avoid inconsistencies between batch goods and samples. Please refer to the specific size matching Discussion of how chemical filter sizes match existing filter frames .

Project judgment example

An old air conditioning box needs to add a chemical filter section, but the original drawings have been lost. The renovation team first went to the site to measure the inner opening, depth and access door dimensions of the installation frame, and took photos and records.

The measurement found that the installation frame was slightly deformed and the sealing surface was uneven. At the same time, the original fan nameplate is unclear and the performance parameters cannot be read directly. These uncertain items were marked in the transformation plan, and the following steps were arranged: first repair the sealing surface of the installation frame, then make a sample for trial assembly, and measure the fan current and air volume.

After the sample is trial-assembled, confirm that the size and sealing match and that the air volume meets the requirements. Installed after mass production, the outlet concentration reaches the target. During the transformation process, unconfirmed items were resolved one by one through on-site testing.

This case shows that without drawings, transformation can still be completed through on-site measurements and sample verification. involving When selecting chemical filter product series , it is recommended to provide on-site measurement data, operating conditions and uncertainties to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s drawing-free transformation 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 modification projects without original drawings, on-site measurement data, operating conditions and target gases can be combined to assist in checking the chemical filtration section configuration and sample verification arrangements.

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