How to choose between ULPA gasket and liquid tank seal?

Gaskets and liquid tanks are two common sealing methods between ULPA and the mounting frame. People often ask 'which one is better' when choosing a model, but this question itself is not quite right.

The two sealing methods solve the same problem - sealing the gap between the filter element and the mounting frame. The difference lies in the implementation method: the gasket relies on the pressing force to allow the elastic material to fill the gap, and the liquid tank inserts the sealing liquid against the knife edge to form a liquid seal. Each has its own applicable conditions, and which one to choose depends on the interface structure, installation method, operating environment and maintenance requirements. For specific sealing structures, please refer to the relevant instructions for liquid tank seal HEPA selection.

First check if the interface can be matched.

This is the most basic step. The sealing method is not selected individually, it must match the structure of the mounting frame.

Gasket seal. The installation frame needs to have a flat sealing contact surface, and the pressing parts must be able to apply pressure evenly. The gasket is usually pasted or stuck on the filter element frame. During installation, the gasket is pressed against the contact surface through a pressing piece. The critical dimensions of the interface are the flatness of the contact surfaces, the position and travel of the hold-downs.

Tank seal. There needs to be a knife edge structure on the installation frame, and a corresponding liquid tank on the filter element frame. During installation, the blade edge is inserted into the groove, and the sealing liquid in the groove forms a continuous liquid seal. The key dimensions of the interface are the position, height and continuity of the knife edge, as well as the width, depth and four-sided fit of the trough.

If the existing installation frame has a gasket structure, replacing it with a liquid tank filter element requires modifying the installation frame; and vice versa. You cannot replace the filter element just because it looks similar in appearance and size. If the sealing interface does not match, it will not seal even if it is installed. involving ULPA ultra-high efficiency filter should be confirmed together with the box interface. The selection and sealing method of

Differences in installation operations

The two sealing methods have different requirements for installation operations.

Gasket seal installation. The operation is relatively straightforward, but the control of the pressing force is the key. If the compression is too loose, the gasket will not be compressed enough, and gaps may appear; if the compression is too tight, the outer frame may be deformed or the gasket may be permanently deformed. The tightening sequence of the clamping parts is also particular. Tightening one corner first may cause the frame to warp. For specific compression requirements, please refer to the instructions related to the compression degree of the gasket.

Installation of tank seal. When inserting the knife edge into the tank body, keep it vertical or at an angle as required by the design to avoid damaging the tank body or causing the sealing fluid to overflow when inserted obliquely. Before installation, confirm the status of the sealing fluid in the tank—whether the fluid level is sufficient and whether there is any leakage or contamination. The liquid tank structure usually has higher requirements for installation accuracy because the matching gap between the knife edge and the tank body is small. For specific verification methods, please refer to the instructions related to the blade edge size.

The difference is more obvious during maintenance. Gasket Seal When replacing the filter element, it is usually necessary to check the condition of the gasket and replace it if necessary. When replacing the liquid tank seal, in addition to checking the blade edge and tank body, you must also confirm whether the sealing fluid needs to be replenished or replaced. The maintenance operation steps of the two methods are different, and maintenance personnel need to follow the corresponding procedures. Device-side applications such as The EFU equipment-end fan filter unit has a compact internal space and limited operating space during installation and replacement. The choice of sealing method must consider actual operational feasibility.

Impact of environment and working conditions

The operating environment has different effects on the two sealing methods.

High temperature environment. Gasket materials may age rapidly, harden, or lose their resilient properties at high temperatures. The sealing fluid of the liquid tank seal may volatilize or change viscosity at high temperatures, affecting the liquid sealing effect. Both methods need to select materials according to temperature conditions. For specific temperature resistance methods, please refer to the instructions related to high temperature environments.

High humidity environment. The resilience properties of the gasket may change after absorbing moisture. If the sealing fluid of the liquid tank seal becomes damp or diluted, the sealing performance may decrease. In high-humidity environments, both methods require confirmation of material suitability.

corrosive media. Both gasket materials and sealants need to be checked for chemical resistance. Certain solvents may cause the gasket to swell and may also affect the stability of the sealant. For specific material selection methods, please refer to the relevant instructions for corrosive gas environments.

vibration environment. The gasket seal may loosen under vibration conditions, and it is necessary to confirm whether the pressing parts have anti-loosening measures. The liquid tank seal is relatively stable, but long-term vibration may affect the distribution of the sealing fluid. Supporting For the FFU fan filter unit system, the impact of unit vibration on sealing must also be evaluated.

Leak detection conditions should also be considered

Regardless of the sealing method, leak detection is required after installation.

Key points of gasket seal leak detection. Scan the contact position between the surrounding frame and the mounting frame to confirm that the gasket is compressed evenly and there is no bypass. Locations where gaskets are displaced, broken, or under-compressed are key areas to inspect.

The focus of leak detection on liquid tank seals. Scan the matching position between the blade edge and the groove body, especially the four corners. The leakage point of the liquid tank seal may be caused by the local knife edge not being inserted in place, the tank body having a gap, or insufficient sealing fluid. For specific leak detection methods, please refer to the relevant instructions for on-site leak detection.

The leak detection methods of the two methods may be the same, but the key points of determination are different. The detection plan should be designed according to the characteristics of the sealing method. involving Acceptance and leak detection requirements for HEPA/ULPA air filters should be specified in the project documents.

Project judgment example

A piece of equipment needs to replace the ULPA filter, and the original product uses a gasket seal. The project team considered switching to liquid tank seals, believing that liquid seals are more reliable.

The investigation revealed that the original mounting frame had a flat contact surface structure without a knife edge. If the liquid tank sealed filter element is used instead, the installation frame needs to be modified at the same time to add a knife edge structure. Renovation involves box processing and re-verification, which is costly and time-consuming.

After evaluation, it was decided to maintain the gasket sealing method, but use gasket materials with better temperature resistance to solve the original problem of gasket aging at operating temperatures. After replacement, the test was retested and the seal was normal.

This case illustrates: The choice of sealing method first depends on whether the interface can match. You can't just look at a certain method as 'theoretically better', but also see whether the actual conditions support it. involving HEPA high-efficiency filter is the same. The selection logic of

Selection and Acceptance Checklist

About Aili Industrial’s sealing solutions

The selection of gaskets and liquid tanks is essentially a matter of matching the installation frame structure, operating conditions and maintenance methods. Whether the interface can be aligned is often more critical than the sealing method itself.

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 the selection of sealing methods, the installation frame structure, working conditions and maintenance requirements can be combined to help check the applicability of the gasket or liquid tank solution. When the filter is matched with equipment such as FFU and EFU, the sealing interface and installation matching dimensions can be uniformly confirmed at the planning stage to reduce air leakage problems caused by mismatched interfaces on site.

When enquiring, provide the installation frame structure, operating conditions and maintenance methods to help confirm the appropriate sealing solution. The specific configuration is subject to the technical documents and test results confirmed by the project.