Manufacture and installation process requirements and quality control points of galvanized steel air duct

Galvanized steel

1. Process requirements

1) Bite connection or riveting should be used, and welding is not allowed;

2) The joints of the air duct panels should be staggered, and there should be no cross joints.

3) The bite seam is tight, the width is the same, the knuckle is straight, the arc is uniform and the two ends are parallel;

4) The air duct has no obvious distortion and warping angle, the surface should be flat, and the unevenness should not be greater than 8mm;

5) The allowable deviation of the outer diameter or the length of the outer side of the air duct is a negative deviation. When the length of the large side of the air duct is less than or equal to 630mm, it is -1mm; when it is greater than 630mm, it is -2mm;

6) The allowable deviation of the flatness of the nozzle is 1mm, and the difference between the lengths of the two diagonals of the rectangular duct should not be greater than 2mm.

7) Reinforcement measures should be taken if the side length of the rectangular air duct is greater than 630mm, the side length of the thermal insulation duct is greater than 800mm, the length of the pipe section is greater than 1250mm, or the single-sided flat area of the low-pressure air duct is greater than 1.2㎡, and the medium and high-pressure air duct is greater than 1.0㎡.

2. Key points of quality control

1) Before riveting the air duct and the flange, conduct a technical quality review, and leave 10mm flanging for the pipe section.

2) When connecting flange rivets, the center line of the rivet must be perpendicular to the board surface, so that the rivet head can press the board tightly to make the seams of the board tightly closed.

3) The riveted flange should be mechanically riveted with a hydraulic riveting machine. The riveting should be firm and the rivet should not fall off or miss riveting.

4) When the air duct is connected to the flange, the width of the flanging shall not be less than 6mm. The flanging shall be even and flat, and it shall be close to the flange. The flanging shall not cover the screw holes.

5) Before using equipment such as shearing machine and biting machine, it should be adjusted according to the thickness of the plate to ensure the processing accuracy of the air duct.

3. Finished product protection measures

1) The air duct processing equipment should be covered with flexible materials and must not affect the operation of the equipment;

2) Cloth shoes should be replaced when entering the workshop, and it is forbidden to step on galvanized steel sheets;

3) Use a rubber hammer with a hydraulic seaming machine when seaming the air duct and knocking on the flanging. Metal hammers are not allowed;

4) Processes such as air duct blanking, jointing, and flange assembly must be performed on flexible carpets, and direct contact between the galvanized layer of the air duct and the ground is strictly prohibited;

5) The semi-finished and finished air ducts must be neatly placed on the square wood, each layer shall not exceed 1.2m, and multi-layer stacking is strictly prohibited to cause deformation of the air ducts;

6) When the finished air ducts are stacked for a long time, they should be covered with plastic film to avoid dust accumulation;

7) The galvanized steel sheets should be placed on a spacious and dry moisture-proof wooden pad. When stacking, they should be numbered according to the system, neat and reasonable, and easy to ship. Handling and loading and unloading should be handled with care to prevent damage to the finished product.

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