Black jacket insulation steel pipe includes spiral steel pipe, straight seam steel pipe and seamless steel pipe. The outer layer of black polyethylene material is called black jacket insulation pipe.
Black jacket insulating steel pipe is made by injecting rigid polyurethane foam plastics into the cavity formed by high pressure foamer between the steel pipe and the outer protective layer at one time, and then using polyethylene to stop the disposal of the outer surface of the steel pipe to form the outermost maintenance layer.
Polyethylene buried directly buried heat insulation pipes, high density polyethylene insulation pipes, directly buried precast heat insulation pipes are tightly separated from the steel pipes, polyurethane rigid foam insulation layer and high density polyethylenes coat pipe, and directly buried insulation pipes are mainly used for urban central heating network, oil delivery pipeline, high cold area water conveyance pipeline and production area. Industrial Pipeline Engineering.
The black jacket polyurethane heat preservation steel pipe is tightly adhered to the outer skin of the steel pipe because of the rigid polyurethane foam insulation layer, which can isolate the infiltration of air and water, and can play a good anti-corrosive role. At the same time, its foaming holes are closed and its water absorption is very small. High density polyethylene shell and FRP shell have good anti-corrosion, insulation and mechanical properties.
In order to strengthen the cohesive force between the jacket layer and the foam layer, the inside and outside surface of the jacket pipe is discontinued. In the experiment, sand blasting coarsening and corona polarization were used. It is tested that these two methods are equivalent to increasing the cohesive force between the jacket layer and the foam layer. However, the use of corona polarization disposal is more efficient and the quality is easier to control. According to the research results of the China Petroleum Pipeline Research Institute, the cohesive force of the foam and jacket can reach 0.70 to 1.42MPa after corona treatment of the inner wall of polyethylene pipe, far exceeding the strength of the foam itself.
However, in practice, after testing, the cohesive force of the inner wall and foam of the jacket pipe which has been consumed by corona after industrial consumption can not reach the above value, but it can reach the 0.05N/m value of the relevant standard request. From several experiments and several engineering applications, this value can be accepted in engineering. In practice, it is necessary to further study how to improve the polarization level in order to achieve better bonding effect.
In order to strengthen the bonding force between jacket layer and counterweight layer, it is necessary to stop coarsening the surface of jacket tube. The outer wall of jacket pipe is stopped by manual polishing with electric wire brush at the beginning, and the appearance quality is not easy to control. At present, mechanical tool grooving method is used to stop disposal. After testing and grinding, the shear strength between jacket layer and counterweight layer can reach about 0.2 MPa. However, if the concrete layer cracks slightly (which is allowed), then part of the concrete may still slip, so how to better stop the coarsening of the outer wall of jacket pipe and avoid cracking (especially cracking at the end) is still the key to affect the quality.
With a brief summary of the straight seam steel pipe on the black jacket, I hope it will be helpful to our customers. If you don't understand or ask for help, please click on our official website: https://www.sdhpgy.com or call for consultation. We will try our best to solve it for you.
