In the design and construction, we must truly understand that the direct burial mode of heating pipelines can be divided into two modes: compensation, direct burial, and non-compensation, direct burial, and laying down the principle, characteristics and application of the two modes. In order to make reasonable design choices, construction is safe, reliable and economical.
1 First of all, the concept must be mastered: there is compensation for the direct burial method, which is to solve the thermal elongation of the pipeline through the natural compensation of pipelines and compensators (such as square and bellows compensators) so as to minimize the thermal stress; Laying, simply put, is that when the pipeline is heated, there is no compensation, but it depends on the strength of the pipe itself to absorb the thermal stress.
2 The basic principle of no compensation laying method: When installing the pipeline, the pipeline is first heated to a certain temperature, then the pipeline is welded and fixed. When the pipeline returns to the installation temperature (temperature decreases), the pipeline is subjected to a certain tensile stress in advance. When the pipeline is hot working, with the increase of temperature, the pipeline stress is zero. When the temperature continues to rise, the pipeline compressive stress increases. When the temperature rises to the operating temperature, the pipeline's compressive stress (thermal stress) is still less than the allowable stress. In this way, the pipe can work normally without the compensation device. This kind of non-compensation method applies the fourth strength theory. The pipeline needs to be preheated during construction and the construction is inconvenient. However, there are a lot of engineering practices at home and abroad. Theoretical calculations are reliable and can ensure safety. Another non-compensation method is the calculation method and stress classification proposed by the Beijing Gas Thermal Design Institute in China in recent years. The stability analysis is used and the third strength theory is applied. This way to give full play to the plastic potential of steel, easy construction, without preheating.
3 The depth of the two types of laying is considered with different factors.
(1) When it is determined that there is a compensation for direct burial laying, the depth of burial shall be considered only because of the effect of ground loading, and the stability of the pipeline will not be destroyed, considering the economy and ease of construction. When adopting the method of compensating for direct burial, it should be buried as shallow as possible. Generally, the thickness of the cover soil is more than 0.6 meters, and it is not related to the size of the pipe.
(2) When using the undisturbed direct burial laying method, the burial depth shall take into account the stability requirements of the pipeline, and the stability shall be related to the thickness of the cover soil when using uncompensated uncompensated buried burial pipelines, and the general ratio shall be compensated. The depth, depth, and thickness of the earth cover should be proportional to the size of the pipe.
4 Whether there is no compensation or laying with compensation in the design, the principle is that the straight pipeline is long and the middle branch is small. When the heating medium does not exceed 100°C, the non-compensation laying method should be preferred, otherwise, the compensation laying should be considered. the way. The specific heat network main line should adopt the uncompensated laying method, while the branch courtyard pipe network should adopt the compensatory laying method. However, some designers prefer to have a compensatory laying and should promote the optimal design.
Micro tubule cluster pipe/tube
With HDPE (high density polyethylene) uPVC as the raw material, ext-ruder is extruded to make plastic molding production, the single hole wall intersect, a kind of cable sheath pipe of close melting boundary.Products are waterproof, moisture-proof, anti-aging, long service life, and good weatherability characteristic, at the same time, since it is a one-time molding integration porous protect casing, so the construction is convenient, increase the number of embedded holes, to improve the construction speed, greatly reduces the engineering unit of materials and construction cost.
The inner wall of this kind of pipe is smooth and can be used for optical cable, which can save working hours, its structure is reasonable, the use value is high, the life is long.It is mainly used for mobile,uni-com, net-com, broadcast and other communication cable sheath.
Application:
It is mainly used for communication cable, telecommunication cable network, length communication line and cable TV broadcast transmission network.It has the advantages of being flexible and flexible, less laying, convenient construction, safe and reliable, and low cost.
Features:
1. Good corrosion resistance, good electrical insulation, at least 50 years.
2. The porous partition is clear, the thread is easy and convenient.
3. The construction is convenient and fast and the construction cost is low.
4. Tight arrangement of holes to improve the utilization ratio of communication holes.
5. Product integration structure, high strength, long service life.
HDPE/UPVC Multi Hole Plastic Pipe
Plastic Pipe With Multiaperture Profile,New Material Pipe,Multiaperture Profile Plastic Pipe
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