Construction steps of polyurethane direct buried insulation pipe

The directly buried insulation pipe can play a role in heat preservation, and can withstand high temperatures, transport high temperature steam, hot water and air conditioning water. Moreover, this kind of directly buried insulation pipe is a relatively good insulation pipe at present. So, let's introduce the direct buried insulation pipe and the installation steps.

1. What are the directly buried insulation pipes?

1. Steel sleeve steel directly buried insulation pipe

This kind of direct buried insulation pipe insulation effect is very good, high temperature resistance 200-600 °C, suitable for high temperature steam, convenient construction, environmental protection is very high, but the price is relative to other direct buried insulation pipes, but if the temperature is high, or choose to buy this direct buried insulation pipe.

2. Polyurethane direct buried insulation pipe

Polyurethane direct buried insulation pipe adopts working pipe + polyurethane + polyethylene jacket pipe (direct burial), polyurethane direct buried insulation high temperature does not exceed 120 °C, suitable for transporting hot water, conveying air conditioning water, according to the temperature of which directly buried insulation pipe is selected, the insulation effect can be better.

Second, the construction steps of directly buried insulation pipe

1. Drilling

1) Before construction, the function and accurate location of the existing underground pipelines and underground structures in the buried pipe site should be understood, and the exploration pit should be manually excavated before each vertical hole is drilled, and the diameter of the exploration pit is not less than 300mm, and the depth is not less than 1.2m

2) When drilling, ensure the perpendicularity of the drill pipe to ensure that each vertical hole is parallel and prevent channeling

3) The project is located in Daxing, there are many sand layers, in order to prevent the vertical hole from collapsing and seepage, the clay is injected into the borehole in a timely manner during the drilling process, so as to improve the quality of the hole and shorten the hole time

3. Vertical down tube

1) Before the pipe, all pipes must be tested for pressure, not less than 0.6MPa, and the pressure must be stabilized for 15 minutes, and the pressure will not drop, and the pressure will not seep or leak, which is considered qualified

2) The PE pipe should be tested in time before backfilling after the pipe is lowered, and the next hole can be drilled only after it is qualified; 3) In order to prevent sediment deposition in the hole and reduce the effective depth of the hole, after the drilling is completed, the pipe should be lowered in time, and fixed measures to prevent the PE pipe from floating should be taken 4) After the pressure test is qualified, the four open ends of the U-shaped pipe should be sealed in time, and the U-shaped pipe should be tied separately in each group to facilitate the pipeline connection in the future

Fourth, horizontal pipe laying, pipeline connection

1) The horizontal buried pipe can not be set slope, the top of the upper buried pipe should be 0.4m below the frozen layer, and not less than 0 .8m from the ground, and the spacing of the water supply and return loop header is not less than 0.6m

2) At present, equipment is often used for electric fusion welding and hot melt welding of pipeline connections. The electrofusion welding has an instrument to control the time, and the welding process is good, but the price of the electrofusion welding parts is higher; Pay special attention to hot melt welding, master the time, and avoid shrinkage holes after welding, or even clogging the pipe

5. Backfill

1) The vertical hole grouting material should be a mixture of bentonite and spun slurry or material, and the mud precipitate generated during the drilling process can also be used to ensure that the borehole grouting is dense and there is no cavity. Otherwise, the heat transfer effect will be reduced and the quality of the project will be affected

2) The backfill of the horizontal coupling should be fine, loose, uniform and free of stones and soil blocks, and the backfill compaction process should be uniform, and the pipeline should not be overhead

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