Rigid polyurethane spray polyethylene winding prefabricated direct-buried insulation pipe is composed of the working steel pipe (core pipe) for conveying medium, polyurethane rigid foam plastic insulation layer, and polyethylene outer protective layer. The thickness of the insulation layer and the outer protective layer can be adjusted arbitrarily within a certain range during production according to needs.
| Inner pipe material |
ubmerged arc welded spiral steel pipe, seamless steel pipe, etc. |
| Design pressure |
P≤1.6MPa |
| Conveying medium |
Hot water, cold water, etc. |
| Design temperature |
T≤140℃ |
| Implementation standard |
GB/T34611-2017 |
| Polyurethane density |
≥60kg/m3 |
| Service life |
Greater than or equal to 30 years |
| Outer protective pipe density |
≥940 kg/m3 and ≤960kg/m3 |
(1) The polyurethane spraying process results in better uniformity of the polyurethane insulation layer density, better stability of the thermal conductivity coefficient, higher closed-cell rate, lower water absorption, and smaller axial eccentricity of the insulation pipe;
(2) The polyurethane insulation layer is formed by free foaming, with the direction of bubble initiation perpendicular to the axial direction of the pipe, improving the compressive strength of the insulation layer.
(3) The bonding performance between the polyurethane insulation layer and the working steel pipe is stronger. (The polyurethane raw material is sprayed in liquid form onto the surface of the steel pipe, then reacts and forms. Due to the high reactivity of the sprayed polyurethane raw material, its bonding force is superior to traditional processes.)
(4) Due to the spray molding, the surface roughness of the polyurethane foam is higher, and the bonding performance with the outer protective polyethylene sheet is stronger.
(5) The polyethylene outer protective layer, while ensuring its performance, is thinner and more uniform, which can save costs.
(6) The polyethylene outer protective layer is formed by circumferential winding. Affected by process stretching, its mechanical performance indicators such as circumferential elongation and tensile strength are significantly improved.
| Work tube engineering diameter
（DN）mm |
Insulation thickness
mm |
Outer protective layer outer diameter
（Dc）mm |
Minimum wall thickness of outer protective layer.
（emin）mm |
| 300 |
30~50 |
393~433 |
4.0 |
| 350 |
30~50 |
445~485 |
4.0 |
| 400 |
30~60 |
494~554 |
4.0 |
| 450 |
30~60 |
547~607 |
4.5 |
| 500 |
30~60 |
598~658 |
4.5 |
| 600 |
30~60 |
700~760 |
5.0 |
| 700 |
30~60 |
790~850 |
5.0 |
| 800 |
30~60 |
891~951 |
5.5 |
| 900 |
30~60 |
992~1052 |
6.0 |
| 1000 |
30~60 |
1093~1153 |
6.5 |
| 1100 |
30~60 |
1194~1254 |
7.0 |
| 1200 |
40~100 |
1316~1436 |
8.0 |
| 1400 |
50~120 |
1538~1678 |
9.0 |
| 1600 |
60~140 |
1760~1920 |
10.0 |
| Note: Other outer diameters of the outer protective layer can be selected according to design requirements,
but the minimum wall thickness of the outer protective layer for steel pipes of the same diameter should be the same. |
● Custom production can be carried out according to user requirements; optional anti-leakage early warning system can automatically detect pipeline network leakage faults, automatically alarm, and has high safety stability.
● The design and calculation of product specifications need to consider specific application conditions, involving more parameters. Please contact Yuanfeng Company.
Product aliases: Spray insulation pipe, spray winding insulation pipe, polyurethane spray insulation pipe, polyurethane spray polyethylene winding insulation pipe, polyethylene winding insulation pipe, spray winding polyurethane insulation pipe, rigid polyurethane spray polyethylene winding prefabricated direct-buried insulation pipe, etc.
