Steel-in-steel direct-buried insulated pipes are mainly used in urban district heating, greenhouses, cold storage, coal-mine and petroleum pipelines at ports, chemical industry, natural gas pipelines, power direct-buried applications, central air-conditioning pipe insulation, cable conduits, steam insulated pipelines, and other industries for thermal insulation and cold insulation projects. Main advantages of direct-buried laying of high-temperature pipelines
Steel-in-steel direct-buried insulated pipe manufacturers are mainly used in urban district heating, greenhouses, cold storage, coal-mine and petroleum pipelines at ports, chemical industry, natural gas pipelines, power direct-buried applications, central air-conditioning pipe insulation, cable conduits, steam insulated pipelines, and other industries for thermal insulation and cold insulation projects. Main advantages of direct-buried laying of high-temperature pipelines:
1. High insulation efficiency and significant energy savings, reducing heat loss by 14–19% (compared with conventional overhead or trench laying)
2. Occupies little land, does not affect municipal planning, and reduces pollution. Especially in areas with dense underground networks and obstacles, trenches often cannot pass, whereas direct-buried pipe can.
3. Convenient installation and short construction period. 4. Long service life and low maintenance cost.
Among insulated pipelines, steel-in-steel insulated pipe is a direct-buried prefabricated insulated pipe with good thermal insulation performance, safety and reliability, and low project cost. It effectively solves the insulation, sliding lubrication, and exposed-end waterproofing problems of prefabricated direct-buried insulated pipes for high-temperature heat transmission at 130°C–600°C in urban district heating. High-temperature prefabricated direct-buried insulated pipe not only offers advanced technology and practical performance that traditional trench and overhead laying can hardly match, but also significant social and economic benefits, and is a powerful measure for heating energy conservation. Steam insulated pipe is a type of underground direct-buried pipeline that can be direct-buried without a concrete structure: thermal expansion of the carrier pipe takes place inside the outer pipe, thereby reducing material cost, shortening the construction period, and safeguarding the heating pipeline. It can be applied more safely across different temperature conditions and is especially suitable for high-temperature steam pipeline projects. Service temperature can reach 150°C–450°C. Pipe ends are generally sealed with polyethylene film or three-layer PE cold-wrap tape to prevent moisture or water from entering before installation or during construction.
