PERT-II type thermal pipe is also called PERT-II type prefabricated direct buried thermal insulation pipe. Its full name is high-density polyethylene outer protective pipe polyurethane foam prefabricated direct buried thermal insulation composite plastic pipe, which is made of high-density polyethylene outer protective pipe and polyurethane foam The plastic insulation layer and the working pipe are closely combined.
a. Outer protective pipe: PERT-II type prefabricated direct buried pipe is made of high density polyethylene pipe;
B, thermal insulation layer: the use of rigid polyurethane foam. Make the heat-resistant polyethylene (PE-RT II) pipe, the outer protective pipe and the insulation layer form a solid whole;
C, working pipe: heat-resistant polyethylene (PE-RT II) pipe.
Advantages:
1. The project cost is low. According to estimates by relevant departments, double-control heating pipelines can generally reduce the project cost by 25% (using glass fiber reinforced plastic as protective layer) and 10% (using high-density polyethylene as protective layer).
2. Low heat loss, energy saving. Because the directly buried pipe is insulated by polyurethane rigid foam, its thermal conductivity is: λ = 0.013-0.03kcal/m · h · ℃, which is much lower than other pipeline insulation materials commonly used in the past, and the insulation effect is improved by 4~9 times. Moreover, its water absorption rate is very low, about 0.2kg/m2. The reason for the low water absorption is that the closed cell rate of polyurethane foam is as high as 92%. The low thermal conductivity and low water absorption, together with the thermal insulation layer and the high-density polyethylene or glass fiber reinforced plastic protective shell with good waterproof performance outside, have changed the situation of "wearing wet cotton-padded jacket" in the traditional trench laying heating pipeline, greatly reducing the overall heat loss of the heating pipeline, and the heat loss of the heat network is 2%, which is less than the international standard requirement of 10%.
3. Good anti-corrosion insulation performance and long service life. Directly buried insulation pipe due to the polyurethane rigid foam insulation layer tightly bonded to the working pipe, isolated from the infiltration of air and water, can play a good anti-corrosion effect. At the same time, its foaming holes are closed and the water absorption is very small. The high-density polyethylene shell and the glass fiber reinforced plastic shell have good anti-corrosion, insulation and mechanical properties. Therefore, the working tube is hardly eroded by the outside air and water. According to foreign information, the service life of polyurethane insulation pipes can reach more than 50 years, which is 3 to 4 times higher than that of traditional trench laying and overhead laying.
4. Less land occupation, fast construction, favorable environmental protection. Directly buried heating pipelines do not need to build huge trenches, but only need to bury insulation pipes underground, thus greatly reducing the project area, reducing the amount of earthwork excavation by about 50%, and reducing the amount of civil masonry and concrete by 90%. At the same time, the insulation pipe processing and on-site trenching are carried out in parallel, and only on-site joints are needed, which can shorten the construction period by about 50%.