1. The traditional construction technology of rock wool insulation in brick warm trench is as follows: digging trench 2 x 2 (m) to lay concrete cushion, burying angle steel bracket of heating pipe, removing rust of steel pipe, painting and anticorrosion, processing and fixing clamp, welding of steel pipe, fixing of steel pipe, water pressure test, rock wool insulation, wrapping glass cloth, brushing asphalt paint, covering plate of trench, backfilling soil.

Among them are the transportation and dumping of digging trenches for soil, the purchase and transportation of sand, cement, bricks, angle steel, rock wool, trench cover, etc. The construction touches a large area with many intermediate links, occupies a large construction site and has a long construction period, and the loss rate of rock wool in the construction and transportation process is more than 10%. Because rock wool fibers have intense irritation to human skin and respiratory tract, it is necessary to take necessary labor maintenance measures.

2. Construction technology of polyurethane direct buried insulation pipe: steel tube pressure test rust removal rigid polyurethane direct buried pipe manufacturing (above work stopped in the factory) digging trench welding of direct buried pipe water pressure test foaming backfill soil.

Directly buried heat-supply pipelines do not need to build huge trenches for thermal insulation. They need only be buried in public, which greatly reduces the construction area, reduces the amount of earthwork excavation by more than 50%, and reduces the amount of civil masonry and concrete by 90%. At the same time, the processing of insulating pipes and digging ditches on site are stopped in parallel, and the construction period can be shortened by more than 50% with only on-site joints.

Compared with other commonly used pipeline heat preservation data, the heat preservation effect is improved by 4 to 9 times. With its low water absorption, high density polyethylene (HDPE) or fiberglass reinforced plastics (FRP) maintenance shell with good insulation layer and external waterproof performance, the situation of traditional trench laying heating pipeline "wearing wet cotton jacket" has been changed, and the overall heat loss of heating pipeline has been greatly reduced. The heat loss of heating network is 2%, which is less than 10% of the international standard requirements.

The manufacture and construction of polyurethane direct-buried insulating pipe can stop in parallel, and digging ditches in the construction site is consumed by the manufacturer, and welding can stop directly after transportation. The construction time is greatly shortened.

This method not only shortens the construction time, but also saves a lot of manpower and material resources. Moreover, the polyurethane direct-buried insulation pipe has no loss in transportation because of its good external corrosion resistance. Therefore, polyurethane direct buried pipe in the pipeline transport industry has been welcomed by people.

In a word, the high temperature prefabricated directly buried insulation pipe not only has the advanced technology and applicability which is difficult to compare with the traditional trench and overhead pipeline laying, but also has remarkable social and economic benefits, and is also a powerful measure of heating and energy saving.