How to choose HEPA liquid tank seal?

Tank seals and gasket seals solve the same problem: sealing the gap between the filter and the mounting frame. The difference lies in the method - the gasket is pressed, and the liquid tank is pressed into the groove with the sealing fluid inserted into the groove by the edge of the knife.

This structure has its place in terms of sealing reliability, but there are also more checklists for selection. The key is not to choose 'liquid tank' or 'gasket', but to confirm whether the matching relationship between the blade edge and the tank body can be established. The size, position, and continuity of the four corners, if any one of them does not match up, the seal will not form a complete circle.

The knife edge and the groove body are their own activities.

The cooperation of the liquid tank seal involves two parts: the box side and the filter element side.

What is marked on the box drawing is the knife edge: outline, position relative to the installation datum plane, knife edge height and thickness. Marked on the filter element drawing is the groove body: the center position of the groove, groove width, groove depth, and available insertion depth.

If these two sets of drawings are measured separately and each is qualified, it does not mean that they will be sealed when put together. The key is whether they use the same installation baseline . The box body uses the flange surface as the benchmark to mark the blade edge position, and the filter element uses the tank bottom surface as the benchmark to mark the tank body position. The benchmarks on both sides are inconsistent, and the reason for the mismatch in size cannot be found.

Putting the two pictures together before placing an order and checking them against the same benchmark is more reliable than confirming them separately. This principle is the same thing as the knife edge size check, except that the perspective is changed from the box to the filter element.

Sealing materials should be confirmed according to working conditions

Not just any material can be used for the sealing liquid in the liquid tank.

Temperature affects viscosity. When the temperature is low, the sealing liquid becomes thicker, and the resistance to inserting the knife edge increases; when the temperature is high, the sealing liquid becomes thinner, and the stability of the liquid seal may change. When selecting, confirm the performance of the material within the operating temperature range, rather than just looking at normal temperature data.

Cleaning agents and process gases also need to be checked. Reagents used for daily disinfection and gases that may be entrained in the air flow may react with the sealing material. If this kind of information is not provided during the inquiry, the supplier can only configure it according to normal working conditions, and it may fail prematurely in actual use.

Another point that is easily overlooked: the sealing fluid of the liquid tank seal may volatilize or age during long-term operation . The replacement cycle and maintenance method need to be specified in the project document. This is not a problem that can be completely solved during the selection stage, but it should be asked clearly when selecting.

Precautions for assembly and transportation

The liquid tank structure has higher assembly requirements than the gasket type.

When the knife edge is inserted into the groove body, it must be kept vertical or at an angle as required by the design. Inserting it at an angle may damage the tank or cause the sealing fluid to overflow. The tightening sequence of the pressing parts is also particular, so that the four sides are evenly stressed to avoid pressing one side first and causing the other side to lift.

The transportation link also needs attention. The tank body must be protected during transportation to avoid deformation or leakage of sealing fluid. During the arrival inspection, in addition to looking at the outer frame and filter material, you should also check the appearance and packaging status of the tank. If the tank body is deformed or has signs of leakage, isolate and record it first, do not install it directly.

For device-side applications such as The EFU equipment-end fan filter unit has a compact internal space and limited operating space during assembly. These details must be taken into consideration during the planning stage.

Verification after installation

The product is qualified before leaving the factory and cannot replace on-site installation inspection.

After assembly, check for leaks according to the agreed conditions of the project, focusing on scanning the surrounding frames and corners. If leaks are found around the edges, first locate the blade edge, groove body and compression structure, and then decide on the treatment method. Do not repair or replace the filter element directly without positioning it . Most of the leakage points of the liquid tank seal are in the matching link, not the filter element itself.

Supporting the FFU fan filter unit and the leak detection path must also be confirmed in the planning stage. The accessibility of the liquid tank type end used by If the diffuser or structural parts block the frame, they may need to be disassembled and assembled during leak detection, which will affect the timing of each maintenance.

Several actions when replacing old filter elements

When measuring the old filter element and box, mark the benchmark respectively, paying special attention to the relative positions of the four-corner seams and the knife edges.

If the original sealing material is aging or there are residues on the tank body, just replacing the filter element with a new one may not eliminate the leakage point. Cleaning and assembly inspection should be included in the replacement operation, not just filter element replacement.

It is recommended to try out the installation in a representative position first, and then arrange the batch after confirming the matching status of the blade and the tank body, the compression effect and the replacement path. For those involving For items with different levels of HEPA/ULPA air filters , the structural dimensions of the liquid tank may be different. When checking, follow the corresponding product information.

About Aili Industrial’s liquid tank product packages

Aili Industrial provides supporting support for HEPA with different sealing structures and corresponding air supply equipment. The product line covers HEPA/ULPA air filters and supporting terminal equipment. Please refer to the product page for specific filtration levels and specifications.

Confirming the interface drawings of both the filter element and the installation frame will help control assembly and leak detection risks. It is recommended to provide the box blade size, tank measured data and operating conditions to facilitate judgment of the suitability of the liquid tank solution.