The pre insulated steel pipe consist of the steel carrier pipe, polyurethane foam insulation layer and hdpe outer jacket layer used on the underground chilled and hot water service pipe for district heating and cooling system. our pre insulated steel pipe also can be designed with alarm line for underground water detection.
Medium temperature: 50°C—140°C
Operating pressure: <1.6Mpa
Laid way: Buried, overhead, trench
Derusting grade of the steel tube: GB/T9823-1988, Sa2.5
Insulation material: Fluoride-Free water foamed rigid polyurethane foam material (foam density: 60kg/m3-80kg/m3
Inner surface treatment of the high density polyethylene pipe:corona treatment
Inner surface tension of the high density polyethylene pipe:≥50dy/cm.
Color: Back ,Yellow or any color you request
Lifespan: 30-50years
Technics: 1.Advanced Corona treatment 2.Impeller blasting 3.Leakage alarm line
Laying method: 1.direct bury 2.built on stilts 3.trench
Usage: 1.urban centralized heat supply 2.warm room 3.coal mine 4.Petroleum 5.chemical and other anti-corrosion insulation field
Steel carrier pipe specifications
| DN≤150 | 20#seamless steel pipe with GB/T8163 standard |
| DN≥200 | Q235B spiral welded carbon steel pipe with GB/T9711 standard |
| steel standard | API. ASTM. DIN. GB, any standard as customer's request |
insulation polyurethane foam specifications
| Density | CJ/T114-4.3.2 | kg/m³ | ≥60 |
| Average pore size | CJ/T114-4.3.1 | mm | ≤0.5 |
| Percentage of close area | CJ/T114-4.3.1 | % | ≥88 |
| Compressive strength | CJ/T114-4.3.3 | MPa | ≥0.3 |
| Water absorption | CJ/T114-4.3.4 | % | immersion in boiling water 90 minutes, bubble water absorption should be not more than 10% |
| coefficient of thermal conductivity before aging | CJ/T114-4.3.5 | W(m.k) | ≤0.033 |
| Cavity | CJ/T114-4.3.1 | ≤1/3the thickness of insulation layer |
hdpe jacket specifications
| Density | CJ/T114-4.2.3.1 | kg/m³ | ≥940 |
| Elongation at braek | CJ/T114-4.2.3.4 | % | ≥350 |
| Tensile yield strength | CJ/T114-4.2.3.4 | Mpa | ≥19 |
| Longitudinal shrinkage rate | CJ/T114-4.2.3.5 | % | ≤3 |
| Long term Mechanical properties | CJ/T114-4.2.3.6 | 80℃4.0MPa | >1500hfree from damage |
| The difference of the melt flow rate | CJ/T114-4.2.3.2 | g/10min | ≤0.5 |