The box-type high-efficiency filters come in two structures: single flange and double flange. In the selection process for cleanroom projects, the type of filter to be chosen should be based on the cleanliness level of the workshop and the requirements for leakage risk control. When installing the double-flange box-type filter, the double-layer flange structure is used to achieve double sealing. The inner flange is attached to the filter body, and the outer flange is fixed to the static pressure box/FFU cabinet. Two sealing rubber strips jointly reduce the probability of air leakage at the frame edges. This type of filter is suitable for high-grade cleanrooms such as TFT-LCD and semiconductor. When installing the filter equipment, the filter body is inserted into the installation frame. First, fix the inner flange, press the sealing rubber pad tightly, then lock the bolts of the outer flange to ensure uniform force on the flange surface and avoid local gaps causing leakage. When replacing the filter, loosen the fixing parts of the outer flange, remove the old filter, clean the contact surface of the installation frame, then install the new filter, and repress the two layers of flanges for sealing.
Equipment features: The double-flange structure not only possesses stable mechanical assembly performance but also demonstrates outstanding overall airtightness. The design of the filter flange seal is based on domestic cleanroom specifications and also refers to ISO16890 and EN1822 standards for efficient filters. The filter box body is generally made of galvanized steel or stainless steel, with a flat contact surface for the flanges, and the sealing rubber strip uses durable EPDM rubber, which is not prone to hardening or shrinking over a long period of use. The single-flange structure has only one sealing surface and is simple to install, mostly used in ordinary GMP workshops and general clean air conditioning systems; the double-flange structure has two sealing layers, providing a higher tolerance for the flatness of the installation surface, and is particularly advantageous in negative pressure clean rooms and high-level clean areas projects. The filter size can be customized according to the on-site conditions. Common specifications are 610×610mm and 1220×610mm, with H13/H14 efficient grades. Under a rated resistance of 250Pa, the rated air volume can reach 1700m³/h. The biggest feature of the double-flange box-type filter is the dual-sealing design, which reduces the risk of system air leakage and ensures a stable particle concentration in the clean workshop, reduces the risk of product contamination caused by frame leakage, and has a simple operation and maintenance replacement process, and is compatible with various clean air conditioning units and FFU air supply units.
