Why do steam pipes often have a bend in them?
We often see such scenes on the steam pipe, it can be "straight" section suddenly bent, believe that many people who like me will be seen such doubt, this is not a "snake", actually otherwise, in operation of the pipeline design has its own principle, let take you to understand the effects of steam pipe bending.
Steam pipeline is divided into two kinds of working condition, a high temperature, an approximation to the environment temperature, in alternating transformation, can produce the displacement and stress because of the principle of heat bilges cold shrink, the longer the pipeline, the bigger the displacement and force, in order to prevent the pipeline damage, need to take measures to avoid, and there was this bending, also known as "expansion joint", is used to absorb tube axial displacement of expansion, also has from the requirement of concrete beams, kill two birds with one stone.
China has relevant provisions on expansion section, for example, Article 4.8.17 of Design Code for Heating Ventilation and Air Conditioning;The heating pipe must calculate its thermal expansion.When the natural compensation of pipe segment cannot meet the requirements, compensators should be set.Others, such as the electric power chemical design specification, even require the use of software for calculation, such as power plant design institute usually uses GLIF, chemical design institute usually uses Caesar, etc.
The compensation amount should be calculated before installation, the installation process requires cold drawing, especially the main steam outlet, the support is also very important, sliding, fixed support key detection, natural compensation should be used as far as possible in the workshop.
So how long is the expansion of the pipe?According to the test calculation, 1 meter long distance, heating 100 degrees, about 1.2mm expansion.In some industries, such as power plants, the temperature of the pipeline can reach more than 500 to 600 degrees.At this point a meter is going to expand by 7 to 8 millimeters.Metal, on the other hand, is a material that can be pulled but cannot be pressed. Imagine the difference between the ambient temperature and the temperature of the railway track is 50 degrees. In the early days, the railway track appeared to protrude.However, when the pipeline moves hundreds of meters or even tens of kilometers, a change in the cold and hot state will generate great stress, which will exceed the limit of the pipeline, and the pipeline will naturally become unbearable, which may lead to serious consequences.
When the natural compensation cannot meet the requirements of the pipeline, we usually use compensators to compensate. Compensators can absorb the cold and hot deformation of the pipeline in the axial, transverse and angular directions, and reduce the impact of equipment vibration on the pipeline.The U-section of the steam pipe acts similarly.
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