The installation process for steel double cleanroom doors requires meticulous operation and a systematic sealing design, controlling the risk of contamination throughout the entire process, from door frame positioning and gap treatment to the selection of sealing materials. Its core lies in eliminating the tiny gaps between the door frame and the wall, and between the door leaf and the door frame, preventing the accumulation or penetration of dust, microorganisms, and other contaminants, ensuring the high cleanliness requirements of the cleanroom environment.
Precise positioning during the door frame installation stage is fundamental to avoiding gap contamination. Before installation, installation baselines must be marked around the door opening according to the design drawings. A laser level and plumb line are used to calibrate the verticality and horizontality of the door frame, ensuring a tight fit between the four sides of the door frame and the wall. For machine-made panel walls, galvanized channels must be added to the edges of the machine-made panels at the door opening, and the door frame is fixed in a clamp-like manner with self-tapping screws to avoid directly opening holes and damaging the wall structure. For handmade panel walls, aluminum connectors are used, and the spacing of the connectors is adjusted to compensate for wall flatness errors. After the door frame is fixed, the gap between the door frame and the wall needs to be filled with special silicone sealant. The silicone should be applied continuously along the gap to form a seamless sealing layer, preventing contaminants from entering through the gap.
The sealing treatment between the steel double clean room door leaf and the door frame is a crucial step in preventing contamination. Steel double clean room doors typically employ a double-layer composite structure. The interior of the door leaf is filled with flame-retardant paper honeycomb or aluminum honeycomb, and the outer layer is covered with galvanized steel or stainless steel. A sealing strip is installed on one side of the door frame. The sealing strip must be made of a dustproof, corrosion-resistant, and age-resistant hollow elastic material, such as silicone rubber or EPDM rubber. Its cross-sectional dimensions must match the door frame groove to ensure that the sealing strip is evenly compressed when the door is closed, forming a continuous sealing line. For frequently opened doors, the sealing strip can be installed in a concealed groove in the door frame to reduce damage caused by hand contact, footsteps, or transportation collisions. If a sweeping strip is required at the bottom of the door leaf, a lift-up design must be used to ensure that the sweeping strip fits tightly against the floor when the door is closed, preventing dust from entering through bottom gaps.
The sealing design of observation windows also requires strict control. Observation windows typically use tempered glass, and a special sealing strip must be used to seal the glass and window frame. The four corners of the strip should be spliced at 45° to ensure no gaps. The connection between the window frame and the door leaf must be filled with silicone, and no self-tapping screws should remain on the glass surface to prevent screw holes from becoming a source of contamination. For double-glazed observation windows, the gap between the inner and outer glass layers must be filled with desiccant and sealed with sealant to prevent moisture condensation from blurring the view or breeding microorganisms.
The sealing of movable gaps must balance flexibility and durability. The overlap gap between the door leaf and the door frame must be controlled by adjusting the hinge position to ensure a uniform gap when the door is closed. A cover strip must be installed in the center seam of double doors, with a sealing strip embedded within the cover strip, forming a second line of defense. For doors that need to be frequently opened, an interlocking device can be installed between the door frame and the door leaf to ensure that the two doors are not opened simultaneously, avoiding cross-contamination.
Details handled during construction directly affect the sealing effect. Before installing the door frame, check the flatness of the wall. If the wall is uneven, repair and level it with epoxy resin mortar. After the door is installed, check its opening flexibility to prevent sagging or deformation that could lead to seal failure. Keep construction tools clean to avoid scratches or stains on the door surface. Construction workers must wear cleanroom suits to minimize the risk of human contamination.
Long-term maintenance is crucial for maintaining sealing performance. Regularly check the weatherstripping for aging and replace any cracked or deformed strips promptly. Use a neutral detergent when cleaning the door and frame to avoid corroding the sealing material. Automatic door closers need regular adjustment to ensure a moderate closing speed and prevent the weatherstripping from shifting due to excessive impact.
