Sealed doors are installed in the passageways connecting the underground main substation and the main drainage pump room to the shaft bottom yard, where they can be easily closed to prevent sudden water ingress. The door leaf of this sealed door is fabricated by welding together flat steel plates, grid-reinforced panels, and ring beams. Sealed Door: A sealed door is a type of door designed to enhance air tightness. Sealed doors can be made of wood or steel, with the sealing device being the key component. “QKB Airbag-Type Rapid Sealing” is a rapid sealing technology and equipment used for fire emergency rescue, temporary containment of localized gas accumulation or over-limit concentrations, and control of localized high-temperature fire sources. This airbag-type rapid sealing system is a domestic first (patented, patent number ZL 97 2 00747.4) and plays a significant role in enhancing mine disaster-resistance capabilities, reducing substantial economic losses and casualties caused by mine fires, and has considerable practical significance. The product is manufactured using antistatic, flame-retardant rubber materials, featuring light weight, portability, simple operation, and fast installation. Structure 1. The door leaf of the sealed door is assembled and welded from components such as flat steel plates, grid-reinforced panels, and ring beams. 2. The door frame of the sealed door is a framed structure composed of channel steel and I-beams. 3. The tensioning mechanism of the sealed door employs wedge-shaped sliding blocks. 4. The door hinges of the sealed door are supported by rolling bearings. Main Features 1. Simple operation; easy for rescue personnel to master. Inflation can be carried out using high-pressure nitrogen cylinders or manually with a bellows. 2. Lightweight and portable, solving the problems of difficult transportation and time- and labor-intensive handling associated with traditional sealing materials. 3. Fast installation—typically taking only 5–7 minutes, with a fastest time of just 4 minutes—for completing a temporary seal. 4. Excellent sealing performance, low air leakage rate, and good air-tightness of the airbag, which can maintain integrity for more than 24 hours without leakage. 5. Wide applicability: suitable for roadways with various cross-sectional shapes and different support structures, offering versatility and adaptability to both large and small spaces. 6. Rescue personnel can conduct routine training in any roadway underground. 7. The airbag seal provides both skeletal support and sealing function, eliminating the need for temporary supports. 8. The airbag seal can also serve as a temporary wind door for temporary airflow regulation. 9. The airbag seal is reusable, significantly saving timber resources. Tangshan Weitian Parameters Model Examples: Serial No. Model Specification 1 MMB1.4*1.8 B85-373 2 MMB1.6*1.8 B85-373 3 MMB1.8*2.0 B85-373 4 MMB2.1*2.0 B85-373 Model Editing MMB (Sealed Door) 1.4 (clear passage width at the tunnel entrance: 1400 mm) 1.8 (clear passage height at the tunnel entrance: 1800 mm)