The so-called stainless steel corrugated compensator is a device structure set or installed to compensate the inductive force caused by temperature difference or mechanical vibration. Its main function is also reflected in the compensation function of the stainless steel corrugated compensator, which is specifically manifested in compensating the deformation of the absorption pipeline, ensuring the contraction rate of the equipment, facilitating the removal and installation, absorbing the vibration effect of the equipment, and ensuring the stability of the pipeline. In addition, due to its high compensation efficiency in recent years, this compensator can effectively reduce the construction cost of the project, has good safety performance, and greatly improves the economic benefits. However, there are still some problems in the actual application. We need to strengthen analysis and research to improve the transportation efficiency of the pipeline by ensuring the normal operation of the stainless steel corrugated compensator. This article will also analyze the causes of the damage of the stainless steel corrugated compensator based on the basic problems, hoping to give readers some inspiration.
Analysis of basic problems of stainless steel corrugated compensator failure
Generally speaking, the pipe wall thickness of the corrugated compensator is very thin. Although the double-layer or three-layer structure is normally used, the bearing capacity of its outer wall is still limited, and the possibility of damage is high. For this reason, the stainless steel corrugated compensation has become a very weak link in the heating pipeline system, and also an important part for us to strengthen management and fault analysis. Many heat supply network accidents and failures are closely related to the corrugated compensator, so we should pay enough attention to the damage of stainless steel corrugated compensator and strengthen management to prevent unnecessary economic losses.
In the whole thermal system, the causes of compensator mainly include three aspects: first, the compensator is damaged due to fatigue or service life, second, the compensator is damaged due to corrosion, and third, the compensator is damaged due to water hammer. During the operation of the actual stainless steel corrugated compensator, we found through investigation that the stainless steel corrugated compensator generally installed in the well or pipe trench is most prone to problems, especially the compensator in some water supply pipes is more vulnerable to damage due to the corrosion of water. Some of these problems can be solved and prevented in the construction design or pipeline design process. For example, in the installation process of the compensator, it should be avoided to use it side by side as much as possible. If possible, it should be misplaced. In addition, it is better to set certain signs at the installation position of the compensator for protection and daily inspection and protection to prevent interference from external factors.
2、 Analysis on the Damage Causes and Prevention Measures of Stainless Steel Corrugated Compensator
（1） Cause of Stainless Steel Corrugated Compensator
1. Cause analysis
From the structure of the stainless steel corrugated compensator itself, it has certain anti-corrosion performance, so it has a relatively long service life and good operation effect. However, due to the scouring and inductive force inside the pipeline for a long time, the compensator must be subject to great impact, and its stability will decline, which will cause certain damage. In addition, the protective measures cannot be implemented, And the failure rate has been greatly improved due to the lack of timely replacement and maintenance. Of course, its own quality problem is also an important cause of damage.
2. Countermeasures
In order to strengthen the management of the stainless steel corrugated compensator and prevent it from being damaged due to its own reasons, the quality of the compensator must be ensured first to prevent damage due to quality problems; Secondly, a comprehensive and effective management system should be formulated to ensure that the management work is effective. The compensator should be regularly inspected and maintained. The compensator that has reached the end of its service life should be replaced in a timely manner. It should not be overloaded, so that the compensator can be effectively prevented from damage.
（2） Corrosion cause analysis and preventive measures
1. Cause analysis
Stress corrosion cracking (SCC) refers to the cracks spontaneously generated by many metals under the action of stress when they are exposed to some corrosives. When the bellows is compressed or stretched during operation, large stresses are generated on its wave peaks and troughs, which provides the conditions for stress corrosion, leading to stress corrosion and bursting of the bellows compensator. There are two conditions causing corrosion. First, there are elements such as Cl and S in the corrosion medium. Second, there is stress in the stainless steel bellows. When the combined action of the two reaches a certain degree, stress corrosion will occur.
2. Countermeasures
When selecting equipment, adopt hydraulic equipment to produce external pressure bellows compensator; When replacing and designing the stainless steel corrugated compensator, the multi-layer stainless steel corrugated compensator with hydraulic forming or tempering and solid melting treatment shall be selected as the material; For the corrugated compensator that continues to be used on the pipe network, the external surface shall be cleaned, the anti-corrosion paint shall be applied, and the thermal insulation materials shall be chlorine free and sulfur free; When the stainless steel corrugated compensator is replaced or newly designed, the ringless corrugated compensator is used; Regularly check the water quality in the pipe network and strictly control the content of Cl and S ions in the water. The axial stainless steel corrugated compensator with pitting corrosion is replaced with a steel sleeve compensator.
Influence of water hammer and countermeasures
1. Cause analysis
For stainless steel corrugated compensator, the impact of water hammer is very huge and obvious. If the force generated by water hammer cannot be released, it will be released inside the pipeline and affect other structural equipment, including the compensator. In general, under the condition of poor drainage at low water level, the possibility of water hammer is the largest. Because the stainless steel corrugated compensator is flexible, its ability to resist water hammer is limited. If it cannot completely resist the force of water hammer, it will be damaged. The damaged parts caused by this water hammer action are all the ripples or flow sleeves of the compensator. Too much water hammer action will cause the ripples to break, causing them to stop working.
Countermeasures
In order to effectively prevent water hammer, first of all, we should do a good job in the design of the pipeline, reasonably determine the diameter of the pipeline, set proper drainage points, and reduce the occurrence of water hammer. At the same time, it is suggested that the bellows compensator should be far away from the fixed support at the elbow and the upturned position, and should be fixed near the other side. In this way, even if there is a small amount of water in the pipeline, the location of the water hammer action point is far away from the compensator, which can greatly reduce the damage to the bellows compensator caused by water hammer. In addition, the use of external pressure axial bellows compensator and the improvement of the guide sleeve form can also play a certain role in preventing water hammer.
Conclusion
In the current thermal power grid, in order to improve the safety of the pipeline and the transmission efficiency, many thermal power systems have started to use stainless steel corrugated compensator, and its scope of application is also expanding. Although this compensator has good use performance and safety performance, we can not relax its safety monitoring and protection work, but should strengthen scientific and technological innovation and research, Strengthen the close cooperation of all departments, strengthen the management of the destruction of stainless steel corrugated compensator, and pay attention to it. Conduct a comprehensive study and analysis of the causes of the destruction, and actively find solutions and countermeasures to further improve the safety performance of stainless steel corrugated compensator, so as to ensure the normal operation of the transmission pipeline.
