Thermal expansion and contraction are natural phenomena, as long as the temperature rises, expansion will occur. For equipment that generates eat during operation, for example, the shaft of a large motor may generate heat and stretch during operation. Therefore, one end must be fixed and the other end must be free, otherwise the extended shaft will cause the casing to tip over. The thermal pipeline of cement enterprises also has this problem.
Due to being installed in a cold state at room temperature, hot gas will inevitably cause its temperature to rise during the production process, resulting in thermal expansion and elongation. If expansion joints are not installed to eliminate or absorb pipeline elongation, it will inevitably cause damage to the structure or support, which should be given sufficient attention.
1、 Expansion joint bearing: 1. As an expansion compensation equipment for thermal pipelines, it can only withstand a certain axial load during operation, so it cannot be installed in curved or easily twisted areas. It should be installed on vertical pipelines. 2. If installed on inclined or horizontal pipelines, install sliding tracks at both ends of the expansion joint to support the pipeline and ensure that the pipeline can slide on the support. 3. When installing the expansion joint, ensure its natural state and size, otherwise it will affect the expansion compensation of the expansion joint in the hot state. Therefore, it is necessary to ensure that the expansion joint is free from external forces in the cold state. 4. The compensation amount for expansion joints of different specifications and models varies. Therefore, in design and selection, the pipeline expansion amount should be calculated based on the length and temperature rise of the pipeline. Sufficient margin should be left for expansion joints that can meet the compensation requirements. 5. After the installation of the expansion joint is completed and checked for accuracy, remove the bolts that originally fixed the inner and outer sheaths, otherwise the expansion joint cannot achieve its function. 6. The expansion sleeve inside the expansion joint has gaps. After installation, materials such as asbestos that do not affect expansion should be filled inside, while also providing insulation.
2、 Other types of compensation: In terms of the cement industry, it mainly refers to compensation for thermal pipelines. Although compressed air pipelines may not have compensation due to their small size and excessive bending, in reality, the bending and deformation of the pipeline can be considered as compensation. Of course, the heat pipeline for waste heat power generation should also comply with relevant standards, such as installing U-shaped compensators within a certain distance. Here are a few examples to illustrate: 1. For example, the steel structure bridge between the structures of a cement enterprise can be fixed at one end and free at the other end to ensure its flexibility and avoid adding additional loads to the structure. 2. For platforms on devices, expansion compensation should also be considered under special circumstances. For example, when the atomized water inside the humidifier tower runs against the wall, the temperature of the cylinder drops significantly, and shrinkage is inevitable. If the platform is rigid, it cannot deform along with it. In severe cases, the platform legs welded to the cylinder will be pulled apart, causing the platform to tilt or even collapse. 3. There are also three air ducts connected to the calciner through expansion joints. Once the compensation is insufficient or ineffective, the calcination furnace will be directly pushed, and strong bending stress will tear the cylinder of the calcination furnace. 4. For the preheater and intake pipe, the expansion joint cannot be directly arranged on the preheater because the left and right stiffness of the expansion joint is poor, which is easy to twist and tear, causing trouble to the system. Therefore, regardless of the type of expansion joint, it should be arranged in a reasonable position, etc.
Although the expansion joint is a static device and not a main unit, its safety function cannot be underestimated; Other types of compensation also play a role, otherwise damage to the structure is inevitable and should be given sufficient attention.
