Plastic air duct is a kind of ventilation duct that is used more frequently now. It has strong corrosion resistance and aging resistance. However, sometimes in the process of use, due to the insufficient length of the air duct or other reasons, it is necessary to hot melt the plastic air duct. However, in order to ensure the security of the connection, the specific precautions are as follows:

• The hot-melt welding gun is connected to the power supply, reaches the working temperature, and the operation can be started only after the indicator light is on.

• When cutting the plastic air duct, the end face must be perpendicular to the axis of the pipe. Generally, special scissors or pipe cutters are used for duct cutting, and a sharp hacksaw is used when necessary, but the burrs should be removed from the section of the duct after cutting.

• The connecting end surfaces of plastic air ducts and pipe fittings must be clean, dry and free of oil stains.

• When welding the elbow or tee, according to the requirements of the design drawings, attention should be paid to its direction, and its position should be marked with auxiliary marks in the straight line direction of the pipe fittings and pipes.

• When connecting, the plastic air duct should be aligned with the flange or collar of the connection, and the position of the air duct and the connector should be fixed first by spot welding with a hot air torch.

• Select the appropriate welding rod and gun muzzle, and weld the connection gap. Pay attention to the welding speed during welding. Too fast speed may cause insufficient welding and cause air leakage.

• After the welding is completed, it is necessary to wait for a certain period of time to cool down.

• After completing all the connection work, it is necessary to carry out strict wind pressure detection and repair the air leakage gap.

When we are conducting the hot melt connection of plastic air ducts, we must control the heating temperature, cooling time, air duct cutting, etc. of the hot air welding torch, so as to ensure the connection quality of the air duct and ensure the correct use.