Analysis of the reasons for the failure of the reliability of the valve on the power station According to the relevant data, it is known that the failure of the power station valve due to many factors in the course of its use is often failed. Once this phenomenon appears it will threaten the use efficiency of the whole power station valve, and even cause extremely serious loss of economic property. Therefore, under the premise of its reliability analysis, the failure of the power station valve must be analyzed and summarized. On the common causes of failure described in detail. details as follows:
1.1 is affected by vibration and noise to make it ineffective. Vibration will make the power plant valves in the process of generating severe shaking, and led to the fixed parts of the valve in the power plant parts vibration, under the conditions of which will appear the phenomenon of power station valve failure. This is closely related to the designers in the design of power plant valves, designers in the design process must be able to reason for several reasons for the vibration reasoning budget, and through experiments to experience the intensity of vibration, the vibration The frequency of the phenomenon can be controlled within the controllable range. Secondly, the damage to the internal parts of the power station valve will also fail, at this time the signal is difficult to transmit, the vibration will continue to occur, eventually affecting it. Finally, there is another reason can also produce failure, it is the phenomenon of resonance. However, this phenomenon is not very common, mainly caused by excessive noise.
1.2 stuck by the impact of its failure. As the name implies, in the production and processing of power station valves, different parts and components are used. During the process of using these parts, wear or corrosion of various devices may also occur due to the friction effect. Once the mechanical equipment is damaged, there will be stuck, and then affect the operation of the entire power plant valves, failure will result therefrom, there are some external factors is due to the impact of physical factors make the parts deformed, or bending, There will also be stuck, resulting in power station valve failure.
1.3 by the pressure fluctuations affect the power station valve failure. Power station valves operate at higher intensities and also fail. The hardness of the spring must be controlled within a certain range, not easy to excellent and not too soft, to choose moderate. Otherwise when the power plant valve will be due to the impact of external forces caused by the spring pressure is too large or too small, thereby reducing the resistance, when the resistance is too small, pressure fluctuations gradually reduce, there will be a variety of quality problems, accompanied by The resonance phenomenon.
1.4 due to external leakage and internal infiltration affect its failure. Before any operation is started, relevant inspection work must be done. In particular, it is extremely important for power station valves to check and clean up beforehand. Due to long-term operation, the machine will appear all kinds of wear and tear, aging phenomenon, and even some small scratches, this time if not promptly, it will cause the power station valve parts damaged or difficult on the normal track Exercising, eventually leading to the phenomenon of internal and external infiltration can also have a very bad valve on the power plant.
1.5 By the rupture of the valve itself to power station valve failure. The quality of the material constituting the valve body is not guaranteed. There are many internal problems such as stomatal blisters and other problems, and the local strength is reduced. In the case of small-scale power station valves, the valves are enlarged due to the collision. Forcibly installing the power station valves may As a result of uneven force uneven rupture of the power plant valve internal environment on the power plant valve is also a big factor, it will cause the valve vibration valve cracks; pay attention to the valve body maintenance, low temperature damage it.
2 DESIGN VALUE POWER PLANT VALVE DESIGN Safe and reliable power station valves are crucial to their efficient operation, so it is important to know the plant's valves before designing them, and choosing materials and valves is an important task. At the beginning of the design, designers should pay enough attention to the use of materials and the production of valve equipment. According to the texture of the material, the power station valves designed to meet the demand can not only ensure the effective operation of power station valves to a great extent, Can save costs, extend the life of power station valves. It can be said that the safe and effective design of power station valves is to ensure the operation of power plant valves based on the design process requires designers can not design by virtue of their experience, according to actual needs, under the premise of the standard reform and innovation, the final good quality .
(1) Because design conditions determine the reliability of the plant's valves, there are a number of factors to consider when designing the plant's valves. Taking into account the function and characteristics of the power station valve, the design of the power station valve can be carried out from the following aspects: there is no jam as the test run, reliable and stable; the vibration will make the power station valve fail to consider, and the design must have strong resistance Vibration function; strength enough big; can be run quickly; small loss; compression performance; sealing effect.
(2) For the design of power station valves working in different environments, different factors in the reliability design of power station valves need to be fully considered. Such as the design work under high temperature valve must consider the material of different thermal expansion coefficient. C · W · Lawton proposed power plant valves in the case of high temperature to consider the high temperature stress and creep fatigue on the various components of the role and influence.
(3) The method of reliability design of power station valve gradually develops from safety factor method to applied probability and statistics method.
3 measures to improve the reliability of power station valves 3.1 structural improvements Through the improvement of the valve structure of the power plant, which has reduced the occurrence of vibration phenomena. The traditional valve shape of the valve parts through digital technology to improve the linear and design to make it more smooth texture, enhance material stability, reduce wear and noise appear.
3.2 Material Improvement Measures Heat treatment process to change the composition of the valve components or internal structure of the power plant to improve the strength of power plant valves. Spray welding, cladding, spraying and other technologies to improve the wear resistance of parts surface. To take chemical and other protective measures to solve the valve damage caused by one of the major causes of corrosion problems.
3.3 Other measures to ensure the cleaning of the power station valve itself and the control media is to improve the reliability of the power plant valve key measures. Ensure the materials, technology and other preconditions, the regular use of power plant valve inspection check (to determine the inspection cycle, in this case refers to those rarely used in power station valves), in order to detect problems early. Power station valve installation position as close to the control object to reduce unnecessary connection pipe and fittings, installation process to avoid strong installation, so as to avoid local stress.
4 Research on the Development Trend of Power Station Valve Reliability In view of a series of problems existing in the valve of power station in our country, the advanced FMEA, FMECA and FrA analysis method can be used to improve it so as to reduce the frequent occurrence of failure. In addition, we must continue to introduce advanced foreign technology and management innovation concept, which will use a variety of new technologies, and establish a sound management personnel mechanism, we can train for their lack of talent to improve their understanding of power station valves in the design In the process of integration of new ideas into them, in-depth study of the causes of various problems. From this perspective, the power station valve system design is not an independent system design, it is interdependent with a variety of disciplines, requiring stability is extremely high, developed countries in this regard made far more than the study My country Therefore, it is necessary to use the performance data of various aspects recorded during the development, testing and use of power station valves to establish the reliability database of power station valves, and to analyze, design and test the reliability of power station valves so as to further standardize the reliability study of power station valves And procedural.
5 Conclusion In conclusion, the main failure modes of power station valves are stagnation, leakage and vibration. The failure mechanisms of the three failure modes should be studied theoretically and engineeringly to find out ways to improve the reliability. It is the key content to study on the reliability of power station valve in the future to strengthen the data collection in the process of valve development, test and use, the theoretical research on the valve failure mechanism of power station, the reliability test and evaluation of power station valve and the establishment of database reliability database of power station.
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[3] Zhaohan Yue. Discussion on the maintenance of power station valves and process [J]. Mechatronic Information, 2010,24 (02): 133-134.
[4] Guo Lifeng, Wang Bangkun. Power station valve repair and green remanufacturing [J]. China equipment engineering, 2012,10 (06): 27.
Yao Guofu. Current Status and Analysis of High-end Valves in China's Thermal Power Plants [J] .Electric Power Technology, 2009,10 (02): 1-12.
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