How to fabricate and install PIR Pre-insulated duct system Part Three

Using a pre-insulated duct CNC cutting machine will definitely improve your duct making efficiency. A pre-insulated duct CNC cutting machine is a computerized cutting machine that cuts fast and accurately.

Experiment method

Tube body flexible impact resistance:

Take a whole assembled air duct, the maximum side length of the air duct should be ≤ 400mm, and the large-area support distance of the air duct should be 1200mm. Use two wooden corrugations with a height and width of 50 × 50 mm, and the sides are longer than the test piece. Use a 5kg sandbag above the middle of the test piece to freely impact the tube body 3 times with a drop of 1m. Check whether the specimen is damaged or not deformed.

The resistance coefficient inspection of the air duct shall be carried out according to the appendix in JC/T20-1999;

The air leakage rate inspection of air ducts is performed in GB50243 No. 425;

The allowable deviation inspection of the size of the air duct is to be inspected with a commonly used steel tape measure;

The inside and outside of the air duct should be clean and level, and the residual pulp should be inspected by visual inspection and hand-feel inspection. The higher surface of the residual pulp should be inspected with a steel ruler.

The air duct connection is bonded by special glue, and the preparation of the special glue is prepared according to the instructions for use of the glue.

Use a wire brush to scrape off 1-2mm of the foam material on the longitudinal bonding surface of the opposite side of the air duct, and then fill the connecting surface of the air duct with special glue (slightly surplus).

Hold the two connected air ducts close together, straight up and down, left and right, and positioned correctly. When positioning, do not move multiple times to prevent the glue on the connecting surface from being squeezed out, resulting in lack of glue.

Remove excess glue from duct connections and fill voids. The surface of the air duct is clean and free of glue hanging.

Set expansion joints. When the length of the straight section of the air duct reaches and exceeds 20m, every other expansion joint. In the middle of the expansion joint, an anti-swing bracket should be provided. When the length of the straight section of the air duct reaches 30m, an expansion joint should be set every 20m, and an anti-swing bracket should be set up.

Air duct installation method

If the air duct is installed horizontally, the spacing between its supports and hangers should meet the requirements in the table below. After the air duct is installed, the support and hanger should be uniformly stressed without obvious deformation, and the cross arm of the hanger should be small.

The support and hanger should not be set at the tuyere or the operation part of the valve, inspection port and automatic control mechanism, and the distance from the tuyere should not be less than 200mm

The distance between the duct brackets installed vertically should not be greater than 3000mm. The bracket can bear the weight of 3000mm duct.

Strengthening measures for large air ducts

The side length of the 25mm insulated duct reaches 1600mm, and the 18mm non-insulated duct with a side length of 1250mm must adopt strengthening measures in the process of making and installing the duct:

1. The length of the air duct can be spliced, scrape the foam 1-2mm deep at the splicing, and bond with special glue. After curing, roughen the surface with emery cloth at 100mm on both sides of the joint, and stick two layers of glass fiber cloth with a width of 200mm and a thickness of 0.2mm with a special glue.

2. Bond the reinforcing strips at the corners in the air duct, and the specifications of the reinforcing strips are 25×40mm in length.

3. Connect the reinforcement column between the upper and lower plates or the left and right plates of the air duct. The reinforcement column of the thermal insulation air duct is a φ50mm cylinder, which passes through a φ10mm screw in the middle and is fixed with a nut. The inner and outer sides of the air duct plate are made of 70×70×7mm glass magnesium plate or galvanized as gaskets, in order to increase the stress area.

Using a pre-insulated duct CNC cutting machine will definitely improve your duct making efficiency. A pre-insulated duct CNC cutting machine is a computerized cutting machine that cuts fast and accurately.

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