Why is there always a bend in the steam pipeline?
We often see such a scene on the steam pipeline. The pipe section that can be “straight” suddenly bends. I believe many people who have seen it will have such doubts as me. This is not “painting the snake to make the most of it”. In fact, the design of pipeline operation has its own principle. Let’s take you to understand the function of steam pipe bending.
The steam pipeline is divided into two working states, one is high temperature, and the other is approximate to the ambient temperature. In the alternation of cold and hot, displacement and stress will occur due to the principle of thermal expansion and cold contraction. The longer the pipe is, the greater the displacement and force will be. In order to prevent the pipeline from damage, measures should be taken to avoid it. Therefore, this bend is also known as “expansion joint“, It is used to absorb the axial expansion displacement of the pipe, but also to avoid the requirements of concrete beams and columns, killing two birds with one stone.
There are relevant regulations for expansion joints in China, such as article 4.8.17 in code for design of heating, ventilation and air conditioning. When the natural compensation of pipe section can not meet the requirements, a compensator should be set up. Other codes such as electric power and chemical engineering design have this requirement, and some even need to use software for calculation. For example, power plant design institute generally uses GLIF, while chemical design institute generally uses caesar.
The compensation amount should be calculated before installation. The installation process requires cold drawing, especially for the main steam outlet. The support is also very important. The sliding and fixed support should be mainly inspected. The natural compensation should be used in the plant as much as possible.
How long is the expansion of the pipeline? According to the test calculation, 1 meter long distance, heating 100 degrees, about 1.2 mm expansion. In some industries, such as power plants, the temperature rise can reach more than 500-600 degrees. At this time, 1 meter will expand by 7-8mm. The metal is a material that can be pulled but not compressed. Imagine that the temperature difference between the rail and the ambient temperature is 50 degrees. In the early days, the rail also protruded. Later, the sectional rail was used to solve this problem. The pipeline is often several hundred meters or even dozens of kilometers. Under the cold state and hot state, a great stress will be produced. If the stress exceeds the limit of the pipeline, the pipeline will not be able to bear it, and may have serious consequences.
When the natural compensation can not meet the requirements of the pipeline, we usually use the compensator to compensate. The compensator can absorb the axial, transverse and angular cold and hot deformation of the pipeline, and reduce the impact of equipment vibration on the pipeline. The U-shaped section on the steam pipe has a similar effect.
Source: China Steam Pipeline Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
If you want to have more information about the article or you want to share your opinion with us, contact us at firstname.lastname@example.org
Please notice that you might be interested in the other technical articles we’ve published: