Insulated steel pipes are steel pipes that have undergone heat preservation processing, ensuring that the internal temperature of the working pipe meets or reaches the required temperature in different operating environments and under the action of external media. They are widely used in liquid and gas transmission networks, insulation projects for chemical pipelines, oil and chemical industries, centralized heating networks, central air conditioning ventilation pipes, and municipal engineering projects. Steel-clad steel composite insulated pipes
Steel-clad steel composite thermal insulation pipes can be divided into two main categories based on different sliding methods:
1. Internal sliding type: The thermal insulation structure is composed of working steel pipe, aluminum silicate, drag-reducing layer, micro-porous calcium silicate, insulation layer, stainless steel fastening steel strip, aluminum foil reflective layer, polyurethane insulation layer, outer steel pipe, and external anti-corrosion layer. The internal sliding type insulated steel pipe is made up of a steel pipe for conveying medium + composite silicate or micro-porous calcium silicate + rigid polyurethane foam plastic + outer steel pipe + glass fiber reinforced plastic shell anti-corrosion protective layer. Various pipe fitting joints have mature thermal insulation treatment technology and reliable quality.
2. External Sliding Type: Insulating structure consists of working steel pipe, glass wool thermal insulation layer, aluminum foil reflective layer, stainless steel fastening steel strip, sliding guide bracket, air insulation layer, outer protective steel pipe, and outer anti-corrosion layer.
External sliding type thermal insulation steel pipe structure: 1. Inner steel pipe 2. Zinc-rich primer 3. Sliding guide bracket 4. High-temperature resistant glass wool 5. Aluminum foil reflective layer 6. Air insulation layer 7. Outer steel pipe 8. Anti-corrosion coating for outer steel pipe
Steel-clad steel composite thermal insulation pipes are a type of underground buried pipeline. They can be buried underground without a concrete structure, with the thermal expansion of the working steel pipe occurring inside the outer pipe, thereby reducing material costs, shortening construction time, and ensuring the safety of heating pipelines. They can be widely applied in different temperature environments with enhanced safety, especially suitable for high-temperature steam pipeline projects. The operating temperature can reach 150℃-450℃. The pipeline ends are generally sealed with polyethylene film or three-layer PE cold wrap to prevent moisture or water from entering before installation or during construction. The thermal insulation material is wrapped in multi-layer staggered bundles, effectively reducing heat loss, and control measures are taken on the outer jacket surface to prevent the formation of cold bridges, ensuring the temperature control of the anti-corrosion layer of the outer jacket. Multi-layer aluminum foil reflective layers wrapped with thermal insulation materials effectively reduce heat loss, making steam pipelines more economical and reasonable. The drainage system adopts a fully enclosed design, with flexible arrangement, reasonable structure, and reliable safety.
The moisture-removal pipe on the steel sleeve pipe can promptly discharge damp gases and also serve as an alarm pipe for daily operations. The thermal compensation is achieved using a bellows compensator, installed inside the sleeve in a direct-burying configuration, eliminating the need for observation wells, facilitating construction and shortening the project timeline. Suitable for transporting steam or other media at pressures up to 2.5MPa and temperatures below 350°C, this product features a steel pipe outer protective layer, offering high strength, resistance to damage, ease of construction and maintenance, and a long service life. Polyurethane-insulated steel pipes are used on medium and small-diameter hot oil transportation pipelines or heating pipelines to reduce heat loss to the soil by adding an insulating composite layer externally. The commonly used insulating material is rigid polyurethane foam plastic, with an applicable temperature range of -185 to 120°C. This material is soft in texture, and to enhance its strength, a layer of high-density polyethylene is applied externally to the insulation layer, forming a composite material structure to prevent groundwater from seeping into the insulation layer. The surface of the steel pipe is treated with shot blasting for rust removal and the outer surface of the protective tube is subjected to corona treatment using a high-pressure polyurethane foam equipment set to improve the bonding performance of the insulating pipe. The insulating layer material is rigid polyurethane foam with a density of 60 to 80 kg/m3, which fully fills the gap between the steel pipe and the sleeve, and possesses certain bonding strength, forming a firm integral structure among the steel pipe, outer sleeve, and insulating layer. Polyurethane foam has excellent mechanical and thermal insulation properties, typically withstanding temperatures up to 120°C. Through modification or combination with other insulating materials, it can withstand temperatures up to 180°C.
