Dalian compressed air pipeline installs the pipes, pipe fittings, valves, etc. in place according to the design requirements, so that the compressed air can be delivered to the user at the specified working pressure. The installation procedures include pipe selection, pipe processing, pipe laying, pipe connection, pipe test and pipe purging.

Dalian compressed air pipe processing includes pipe cutting and bending. (1) The pipe is bent. The method of cold swab or hot withdrawal can be adopted. The method of cold withdrawal shall be adopted for pipe diameter DG ≤ 150mm, and the method of hot plunger shall be adopted for pipe diameter DG > 150mm. When there is no cold swab machine, the small diameter pipe can also be swabbed by heat.

(2) Pipe cutting. Mechanical or manual cutting shall be adopted for pipes with nominal diameter n less than 50mm and high pressure pipes with nominal diameter n more than 50mm. Flame cutting shall be adopted for pipes with medium and low pressure and large diameter (DG > 50mm).

Dalian compressed air pipeline is made of seamless steel pipe, which is commonly used for compressed air pipeline. Appearance inspection shall be conducted for pipes and fittings. The pipes of high-pressure pipelines shall be subject to nondestructive testing by magnetic flaw detection and other methods. The pipes shall be derusted and coated with anti rust paint before processing, and the valves shall be cleaned, ground and hydrostatic tested.

After the connecting pipe of Dalian compressed air pipeline is hoisted in place, it shall be aligned and adjusted. After the elevation, center line and slope are correct, it shall be connected and fixed. All outdoor pipes are welded. The pipes with a diameter of no more than 50mm are generally gas welded, the pipes with a diameter of more than 50mm are electric welded, and the high-pressure pipes are all electric welded or argon arc welded. When the branch pipe is led out from the main pipe, a tee must be opened from the upper part of the main pipe to prevent the condensed water and oil stain in the main pipe from entering the branch pipe and equipment. The tee of high-pressure pipeline shall be drilled, and flame cutting is not allowed. The compensator shall be pre stretched before the pipeline is fixed, and the stretching amount shall be 1 / 2 of the design expansion amount.