Mining corrugated board iron air door

Mining corrugated board iron air doorA complete system for maintenance and upkeep needs to be constructed from four levels: daily inspection, regular maintenance, special maintenance, and emergency response. Specific measures are as follows：

1Mining corrugated board iron air doorDaily inspection: Real time monitoring, prevention and control

1. Running status check

• Observe the smoothness of the opening and closing of the air doorCheck if there is any jamming, abnormal noise or shaking during the opening/closing process of the door leaf. If there is any, stop immediately and investigate mechanical faults (such as hinge wear and balance mechanism failure).

• Sealing performance testingConfirm the fit between the sealing strip and the door frame through tactile or smoke testing. If any air leakage points are found (such as aging and cracking of the sealing strip or deformation of the door frame), the location should be recorded and marked as a key repair item.

• Calibration of sensors and control systemsFor air dampers equipped with automatic control, check whether the readings of sensors (such as air pressure sensors and position sensors) are accurate, and whether the control logic (such as interlock and delayed closure) responds normally.

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2. Environmental adaptability inspection

• Assessment of Tunnel EnvironmentConfirm that there is no mud, water or debris accumulation within 5 meters around the air door, and that the roadway support is intact (without roof delamination or wall cracking), to avoid external impact causing deformation of the door body.

• Corrosion risk assessmentIn acidic mine water (pH ≤ 5) or high humidity environment, check whether the surface coating of the door body (such as hot-dip galvanized layer, epoxy resin) has peeled off or rusted, and focus on observing the welds and bolt connections.

2、 Regular maintenance: System maintenance to extend lifespan

1. Cleaning and anti-corrosion treatment

• surface cleaningUse a high-pressure water gun or soft bristled brush to remove coal dust and oil stains from the surface of the door leaf and door frame, avoiding particles from embedding into the sealing strip and causing wear.

• Anti corrosion coating repairFor locally damaged coating areas, first sand the metal substrate with sandpaper, and then spray anti-corrosion paint compatible with the original coating (such as zinc based coating), with a thickness that meets the design requirements (such as epoxy resin coating ≥ 120 μ m).

2. Key component maintenance

• Sealing strip replacementIf the sealing strip hardens, loses elasticity, or accumulates more than 50% compression, it needs to be replaced with a product of the same specification (such as EPDM rubber sealing strip) as a whole, and ensure that there is no twisting or stretching during installation.

• Lubrication of hinges and balance mechanismsRegularly add lithium based grease (such as NLGI No.2) to the hinges, connecting rods, cylinder piston rods, and other moving parts of pneumatic/electric dampers to reduce friction and wear.

• Pneumatic system maintenanceCheck if there is any air leakage in the compressed air pipeline (pressure decay ≤ 0.05MPa/min), clean the impurities in the filter, and test the response time of the pneumatic valve (≤ 0.5 seconds).

3. Structural fastening and calibration

• Bolt connection inspectionUse a torque wrench to check the pre tightening force of the bolts connecting the door frame and the roadway anchor, as well as the bolts connecting the door leaf and the door frame (such as the M20 bolt torque needs to reach 300-350N · m), to prevent loosening and structural instability.

• Diagonal dimension calibrationMeasure the length of the two diagonal lines of the door frame using a laser rangefinder or steel tape measure, with an error controlled within ± 3mm, to ensure that the door leaf opens and closes without any obstruction.

3、 Special maintenance: targeted and precise measures for specific scenarios

1. Special Project for High Gas Mines

• Explosion proof performance testingConduct air tightness tests on the explosion-proof junction box and cable entry device of the air door every quarter (pressure ≥ 0.1MPa, maintain no leakage for 1 minute) to ensure that the explosion-proof level (such as Ex d I Mb) meets the standards.

• Gas monitoring linkageIf the air door is linked with the gas monitoring system, it is necessary to regularly test the automatic closing function of the air door when the gas concentration exceeds the limit (such as ≥ 1.0%), and the response time should be ≤ 10 seconds.

2. Soft rock roadway special project

• Elastic sealing strip adaptability adjustmentAccording to the deformation of the surrounding rock in the tunnel (such as monthly monitoring data), dynamically adjust the compression amount of the sealing strip (such as gradually increasing from 30% to 50%) to ensure the sealing effect.

• Secondary reinforcement of door frame anchor rodIf the deformation of the tunnel causes the door frame to tilt (angle>2 °), it is necessary to reinstall the anchor rod (depth ≥ 1.5m, anchoring force ≥ 100kN) and use a hydraulic jack to correct the position of the door frame.

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