2) Prefabricated direct-buried insulated pipe and compensators shall be lifted and handled gently. Impact, throwing, and direct lifting with steel wire are strictly prohibited. Bellows must not be subjected to torsional force.

　　3) The bellows compensator and the pipeline must be concentric, with height difference not exceeding ±5 mm. A dummy pipe of equal actual length shall be trial-fitted at the compensator location; after the pipeline is relatively fixed, remove the dummy pipe and then install the bellows.

　　4) Installation of the moisture-venting system: on each fixed point of the steam line, the moisture vents of our products are generally located here. During installation, the openings must be opened, and exhaust devices installed on site according to local geographic conditions.

　　5) Installation of drain devices: Prepare the drain well in advance. Generally, an overhead drain arrangement is used. Installation must be carried out according to the dimensions of different steel pipes, with proper sealing, so that water in the piping system is led to the drain well and then to surrounding inspection wells. During operation, the valves and steam traps of the drain system should be opened; at the end of start-up, the start-up drain should be closed.

　　6) After NDT, hydrostatic testing, and insulation and anti-corrosion work are all complete, the prefabricated insulated pipes may be cleaned by blowing. Typical media include water, compressed air, and steam. If water flushing is used, continue until clear water flows from the pipe end.

　　7) After purging is completed, steam may be admitted to the steam pipe. The first step is to warm the pipe: open all drain valves fully, admit steam, and raise the temperature slowly, preferably at 2℃/minute. When the temperature reaches 120℃-130℃, stop heating and hold for a period to fully steam-dry residual water in the pipeline and moisture that entered the insulation during construction. When the outlet steam no longer carries moisture and the vent pipes no longer emit steam, heating may continue at the original rate until working temperature is reached.

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