With the deepening development of a resource-saving and environmentally friendly society, the concept of environmental protection and energy conservation has been integrated into all aspects of life and production, gradually becoming a trend of the times. How to embody the concept of environmental protection and energy conservation in thermal pipelines, greatly reduce heat loss, and achieve optimized and rational allocation of resources has become a key and difficult issue for various technical personnel to study and explore at present. Applying corrugated pipe expansion joints to thermal pipelines can not only minimize the loss of heat during transportation, but also supplement its heat to a certain extent.
1. Selection skills for bellows expansion joint models
1.1 Classification of bellows expansion joints
Under normal circumstances, the corrugated pipe expansion joints sold on the market can be roughly divided into two categories. One is the constrained expansion joint, which is more common in hinge type expansion joints, large pull rod transverse expansion joints, etc. Its composition is relatively simple, and the corrugated pipe system does not need to add any fixed supports to achieve a high blind plate load-bearing effect; The second type is unconstrained expansion joints, which require fixed brackets to be installed on the piping system to support axial forces. Common types include universal expansion joints, axial expansion joints, etc.
1.2 Model selection principles for bellows expansion joints
During the expansion and selection process of corrugated pipes, technicians should connect with the actual pipeline construction to match the model of the thermal pipeline. When selecting models, complex pipelines should be subdivided and simplified into typical sections of expansion pipelines, which can be "broken down into parts" and divided into different "one line", "L-shaped" or "Z-shaped" pipeline shapes for later construction and management. After the disassembly is completed, technicians should set the optimal expansion joint model according to relevant conditions and actual needs, and select the matching guide bracket based on its expansion deformation trajectory. In addition, technicians also need to understand the specific parameters such as blind plate force and fatigue service life of the expansion joint of the corrugated pipe, in order to ultimately determine the number of brackets and optimal fixing positions.
1.3 Specific requirements for using bellows expansion joints
(1) Follow the "1:1" rule to set expansion joints
The installation of corrugated expansion joints on a straight thermal pipeline should follow the "1:1" ratio rule, that is, one fixed bracket should be equipped with one expansion joint, and two or more expansion joints should not be installed to avoid uneven load, which seriously endangers the heating efficiency and safety of the thermal pipeline.
(2) The stiffness and strength of the bracket need to meet relevant standards
When selecting fixed brackets, quality should be strictly controlled, and the focus of testing should be on the stiffness and strength of the brackets to ensure that the quality of the brackets used for thermal pipelines meets the standards as much as possible. In addition to the fixed bracket, attention should also be paid to the data of components such as guide brackets and spring hangers to observe whether they can match the displacement form of the expansion joint. If not, timely adjustments should be made.
(3) Same pipe diameter
When proportioning materials, it is necessary to add secondary fixed brackets of the same diameter together and ensure that they are on the same horizontal line as much as possible, which greatly reduces the actual bearing value of the blind plate force of the secondary fixed brackets and achieves the goal of improving the safety factor of the thermal pipeline and extending its service life.
2. Precautions for the construction and installation of corrugated pipe expansion joints
2.1 Pre deformation of bellows expansion joint
Normally, the quality and pre deformation of bellows expansion joints are systematically monitored and analyzed by relevant inspection personnel before production to ensure the service life and safety factor of the expansion joints. However, the pre deformation detection of the manufacturer only stays at the absorption of axial displacement by the expansion joint, which has certain one sidedness and limitations and cannot reflect its overall pre deformation amount. In this regard, technicians need to clarify the type of expansion joint and the pre deformation detection requirements for this type of product before formal installation. The expansion joint that needs to be tested should be subjected to secondary testing through cold drawing to fully understand its actual absorption of lateral and angular displacement, laying a solid foundation for subsequent installation work.
2.2 Reasonable pre stretching and compression
Before installing the bellows expansion pipe, technicians should conduct a thorough analysis of the installation environment, observe changes in temperature and humidity around it, and obtain the most authentic and effective first-hand information. Based on this, scientifically and effectively pre stretch the expansion joint of the corrugated pipe that needs to be installed, ensuring its safety and stability performance to a large extent, and enabling it to play its due role in the thermal transmission process.
2.3 Ensure installation quality meets standards
Technicians must prioritize safety and quality during installation operations, improve installation efficiency while ensuring quality, strictly follow relevant technical operation procedures, and not arbitrarily change or add or remove operation steps for the sake of convenience. They should pay attention to the standardization and rationalization of installation, and must not forcibly bend corrugated pipe expansion joints to conform to the trend of thermal pipelines, so as not to leave hidden dangers for safe operation.
3. Force analysis of fixed supports for thermal pipelines
3.1 Force analysis of the main fixed bracket
Normally, the main fixed bracket is set at the endpoint of the thermal pipeline, at various branch points, and at the installation points of various types of valves. It needs to withstand forces from all parties, such as internal pressure thrust, various frictional forces, and the force generated by the expansion joint of the corrugated pipe during continuous displacement. This requires construction personnel to strictly control its stress situation, comprehensively, objectively, and thoroughly consider all factors that may affect its stress value, and through repeated analysis and comparison, grasp its actual stress value and type.
3.2 Force analysis of fixed bracket
The secondary fixed bracket is also an important component of the fixed bracket, which plays a positive role in the normal operation of the thermal pipeline. During the specific installation process, technicians can choose hinge type or compound universal bellows expansion joints to achieve the function of bearing internal pressure thrust. Afterwards, secondary fixed brackets can be added to effectively share the remaining load force, laying a solid foundation for the safe and stable operation of thermal pipelines.
4. Conclusion
In summary, expansion joints are a type of metal expansion joint that is suitable for use in thermal pipelines with low temperatures, low pressures, and short lengths. They have strong economic, practical, and space saving properties, and can effectively optimize and allocate resources to ensure the normal operation of thermal pipeline heating. Due to the strong plasticity of expansion joints and the softness of the pipe body, technicians are required to strictly follow relevant regulations during the specific installation process, implement each operational requirement, and fully utilize the positive role of expansion joints. On the basis of safety and stability, the working efficiency of thermal pipelines should be improved as much as possible, effectively reducing the loss of heat during transportation.