Precast direct embedded insulated steel pipe is a kind of prefabricated heat insulation pipe with good thermal insulation performance, safety and reliability, and low engineering cost. Effectively solve the city central heating in 130 ℃ to 600 ℃ high temperature heat losing use of prefabricated directly buried insulating pipe insulation, sliding lubrication and bare tube end waterproof problems. It is a new starting point for the development of heating pipeline technology in China.

It is widely used in the pipeline network of liquid and gas, oil, chemical industry, central heating and heat network, central air conditioning and ventilation ducts, municipal engineering etc.

Precast direct embedded insulated steel pipe is composed of steel pipe, glass steel inner sheath and glass steel shell. The features are: high temperature insulation insulation layer, lubrication layer and elastic seal.

1. Working steel pipe: according to the technical requirements of conveying medium, steel tube, seamless steel tube and double-sided submerged arc spiral welded steel pipe are adopted.

2. Insulation layer: rigid polyurethane foam plastic.

3. Protective case: high density polyethylene or fiberglass.

4, leakage alarm line: manufacturing high temperature, the prefabricated directly buried insulating pipe are in close to the steel pipe insulation, embedding a warning line, once the pipeline leakage somewhere, conduction through the warning line, can be on the special detecting instrument alarm and show the leaking of accurate location and the size of the degree of leakage, in order to inform the maintenance staff quickly deal with a leaky pipe section, to ensure the safe operation of the heat supply network.

Advantages of precast direct buried insulated steel pipe:

1. Small area, fast construction and favorable environment protection.

Prefabricated directly buried insulating pipe don't need to laying large cooking, just put the insulation pipe buried underground, thus greatly reduces the project covers an area of, reduce earthwork excavated volume of about 50%, 90% decrease civil masonry and concrete. At the same time, the heat preservation tube processing and the site ditch parallel to carry out, only the spot joint, can shorten the working period about 50 %.

2. Anti-corrosion, good insulation and long service life.

Due to the outer skin of the steel pipe, the precast direct buried insulated steel pipe can have a good anticorrosion effect by isolating the air and water. At the same time, its foaming hole is closed, the absorbent is very small. High density polyethylene shell and glass steel shell have good corrosion, insulation and mechanical properties. Therefore, the outer skin of the working steel tube is hard to be eroded by outside air and water. As long as the pipeline internal processing water quality good, according to foreign materials, high temperature of prefabricated directly buried insulating pipe service life can reach more than 50 years, than the traditional cooking, laying overhead laying 3 ~ 4 times higher service life.

3. Reduce project cost.

According to the relevant departments of the measure, the double control heating pipes, usually can reduce the project cost 25% (using glass fiber reinforced plastic protection layer), and 10% of the protective layer (using high density polyethylene).

4. High safety performance.

Production of prefabricated directly buried insulating pipe outside China, there are leakage alarm line, once the pipeline leakage occurs, somewhere by the conduction of alarm line, can be on the special detecting instrument shows the position of the thermal insulation pipe water seepage, leakage and the size of the leakage degree, in order to notify the inspection personnel quickly deal with a leaky pipe section, guarantee the safe operation of the heating pipe network.

In general, prefabricated directly buried insulating pipe is not only a traditional cooking and aerial pipeline laying incomparable advanced technology, practical performance, but also has significant social and economic benefits, is also a powerful measures of heating energy saving. The use of direct buried heating pipeline technology indicates that the development of China's heating pipeline technology has entered a new starting point. With the further improvement and development of this advanced technology, it is imperative that the heating pipes be buried and replaced.