How to troubleshoot the failure of liquid tank seal ULPA?

The failure of the liquid tank seal is usually manifested by continuous abnormal readings along a certain edge or corner during on-site leak detection.

Different from local point-like signals like pinholes in the filter material, the signal of liquid tank failure is often a continuous high level along the sealing path. This feature alone is a clue— the problem may not be with the filter media, but with the seal path. However, the signal characteristics only indicate the direction, and the final positioning still depends on segment-by-section detection and structural inspection. For specific leak detection methods, please refer to the relevant instructions for on-site leak detection.

First confirm the detection conditions and signal characteristics

Before troubleshooting, please confirm the testing conditions clearly.

Is the air volume stable? The leakage signal of the tank seal may be affected by the air volume. When the air volume fluctuates, the edge readings may shift overall, which is not necessarily a sealing problem. Keep the fan gear stable during the test and record the operating mode. Supporting FFU fan filter unit system, unit status and air volume data must be recorded together.

Whether the signal is repeatable. If the same position is scanned multiple times and the signal appears repeatedly, it is more likely to be a stable leak. Occasional reading fluctuations may result from upstream concentration changes or instrument response.

Signal distribution characteristics. Is it continuous along one side, concentrated at a certain corner, or are there abnormalities on all four sides? Different distributions correspond to different investigation directions. If one edge is abnormally continuous, it may be related to the local deformation of the knife edge or the discontinuity of the tank body; if all four sides are abnormal, it may be related to the overall installation deviation or insufficient sealing fluid. For specific positioning methods, please refer to the relevant instructions for leak positioning.

Check colloid status

The sealing liquid of the liquid tank seal is the key to forming a liquid seal. Abnormal colloid state will directly affect the sealing effect.

Is the fluid level sufficient? When opening for inspection, confirm whether the sealing fluid level in the tank is within the normal range. A liquid level that is too low may result in the inability to form a continuous liquid seal after inserting the knife edge. Insufficient liquid level may be caused by late replenishment, leakage or evaporation. For specific material selection, please refer to the relevant instructions for liquid tank seal HEPA selection.

Whether the colloid is aged or contaminated. Sealing fluid may age, thicken, or become contaminated after prolonged use. Color changes, abnormal viscosity or the presence of foreign matter may affect the sealing performance. If there is dust or chemical media in the operating environment, the sealing fluid may be contaminated, and it needs to be evaluated according to project requirements whether to replace it.

There are no traces of spillage. Overflow of sealing fluid may indicate that the fluid level is too high, or that the blade is inserted at an improper angle during installation, causing fluid to be squeezed out. After overflow, the liquid level in the tank drops, which may result in insufficient local sealing. Check whether there are any traces of liquid residue on the outside of the tank and near the installation frame.

Check the fit between the blade edge and the groove body

The matching state of the knife edge and the tank body is the basis for whether the liquid tank seal can be established.

Whether the knife edge is continuous. Check the edges and corners of the knife. If the blade edge is bent or deformed or the seam is bulged, it may cause partial insertion failure. The four corners are prone to problems and need to be confirmed individually. For specific verification methods, please refer to the instructions related to the blade edge size.

Whether the insertion depth of the knife edge is consistent. Observe the state of the knife edge entering the groove body and confirm whether the insertion depth on the four sides is even. If one side is inserted too shallowly or too deeply, it may be related to the flatness of the installation frame, the placement status of the filter element, or the compression method.

Is the tank complete? Check the tank body for cracks, chips or residue. If there are impurities or sediments in the sealing liquid in the tank, it may affect the contact between the knife edge and the liquid.

Is there any eccentricity in the installation? When the filter element is placed in the installation frame, if the position is offset, the blade edge on one side may hit the wall and the other side may be insufficiently inserted. Check the installation status and confirm whether the relative position of the filter element and the installation frame is centered.

Installation deviation and structural problems

The failure of the liquid tank seal is sometimes not a problem with the filter element or sealing material itself, but is caused by the installation structure or operation.

Whether the installation frame is flat. The deformation of the mounting frame will cause the relative position of the blade edge and the groove body to change. Check the flatness and dimensional accuracy of the mounting frame.

Are support structures in place? If the support below the filter element is uneven, the filter element may tilt or partially sink, affecting the insertion state of the knife edge. Device-side applications such as The EFU equipment-end fan filter unit has a compact internal space, and the support structure and installation flatness need to be carefully checked.

Whether the fastening method is reasonable. The distribution and tightening sequence of the pressing parts will affect the stress state of the filter element. Tightening one corner first may cause the filter element to tilt or the frame to deform, thus affecting the sealing fit. Tighten gradually in the order required by the design to avoid local overpressure.

Is there any displacement during operation? System vibration or pressure fluctuations may cause the filter element to shift slightly during operation. Check whether there are anti-displacement measures after installation, and confirm whether the positioning structure is normal when replacing the filter element.

Processing methods and re-inspection verification

After locating the cause of the failure, handle it in the corresponding way.

Sealing fluid problem: Replenish or replace the sealing fluid, and confirm the fluid level and material specifications according to the product instructions. Do not mix sealants of different specifications at will.

Problems with the blade edge or tank body: If the blade edge is deformed or the tank body is damaged, follow the model instructions to evaluate whether it can be corrected or the filter element needs to be replaced. involving ULPA ultra high efficiency filter or HEPA high-efficiency filter has the same logic. The processing of

Installation problems: Adjust the installation frame, support structure or compression method, and reinstall the filter element. Do not compensate simply by increasing the compression force.

Retest after treatment is completed. Re-scan the sealing path under the same working conditions to cover the location and surrounding areas where abnormalities were previously found. After confirming that the leakage points have been eliminated, keep records before and after the treatment. If the liquid tank fails repeatedly at the same location, it is recommended to check the status of the installation frame and whether the filter element replacement operation is standardized.

Project judgment example

During the ULPA on-site leak detection of a certain equipment, it was found that there was a continuous abnormal reading on the left border. This location uses a liquid tank sealing structure.

Troubleshooting process: First confirm that the air volume and operating mode are stable, and the abnormal signals are repeatable. After opening and inspecting the tank, it was found that the sealing fluid level on this side was low and there was a small amount of sediment at the bottom of the tank. Check the knife edge. The four sides are basically continuous, but there is a slight deformation near the knife edge on the left side. Looking back at the installation records, the position of the filter element was adjusted during installation and may have hit the knife edge.

Treatment method: clean the tank, replenish the sealing fluid, replace the filter element and reinstall it. When installing, confirm that the four sides of the blade are inserted evenly, and tighten the pressing parts in order. The abnormality disappeared after retesting. This location is marked in the record as a key inspection area for subsequent leak detection.

This case shows that the cause of tank seal failure may involve both the sealing fluid state and the installation operation. When troubleshooting, you need to confirm each item one by one, and you cannot just deal with one of them.

Selection and Acceptance Checklist

About Aili Industrial’s liquid tank sealing package

Whether the liquid tank seal can be stable for a long time depends on the cooperation of the sealing material, the cooperation of the knife edge tank body and the installation operation. The knife edge size and groove body consistency are controlled during the manufacturing stage of the product, and the fault tolerance space for on-site installation will be larger.

Aili Industry has independent manufacturing capabilities in filters, fans, control systems and sheet metal processing, and can provide ULPA ultra high efficiency filter、HEPA high-efficiency filter and supporting air supply equipment. For liquid tank sealing projects, the installation frame structure, operating conditions and maintenance requirements can be combined to assist in checking the matching dimensions of the blade edge and tank body. When the filter is matched with equipment such as FFU and EFU, the sealing interface and installation coordination can be uniformly confirmed at the planning stage to reduce air leakage problems caused by coordination deviation on site.

Providing sealing structure drawings, installation records and leak detection data during inquiry or inspection will help confirm the appropriate treatment direction. The specific configuration is subject to the technical documents and test results confirmed by the project.