Key words: industrial valve; petrochemical plant; application CLC: TE927 + .7 Document code: A Article ID: 2095-2945 (2017) 29-0147-02
1 The Benefits of API Valves JB's standard flanges and valves have for decades been used as the standard for piping design, with a rough estimate of the four-fifths of the flanges and valves on the pipeline currently being used in petrochemical plants Made according to JB specification. As a result, JB valves will continue to be widely used for a long time to come. Most petrochemical manufacturers stock JB valves. In particular, some manufacturers that rehabilitate their old installations are inclined to continue using JB valves in order to eliminate the inconvenience of alternation between old and new ones and to make the replacement of old ones and new ones more convenient. Even so, JB valve still has many problems. After the API valve is manufactured and popularized in China, its perfect serviceability will soon be favored by petrochemical production enterprises. API valves are more perfect than other valves in terms of application system and structure .
1.1 API valve has a more perfect application system JB standard uses a unified code to represent a type of valve, and the existing product catalog can be found, the manufacturer only gives an extremely limited range of options, allowing users to choose the time To the limit, that is, the user can not choose the appropriate valve to use. For example, in the case of relatively high temperatures, users will be more flexible gate valve selection, and in the sample generally can only see the maximum size is the DN 200 flexible gate valve. Under normal conditions, the bevel gear drive structure is better than the spur gear drive structure, but the bevel gear drive structure provided in the sample has a very narrow range of valve sizes, so spur gear-driven valves must be selected in the design. In the design, the valve sealing subassembly and the packing structure are generally selected according to the conditions of use, and the models in the sample are generally unable to meet the needs of users. If the selected valve is beyond the scope of the sample, many manufacturers will treat it as a non-standard valve to increase its price, and the delivery date can not be guaranteed.
API valve can be a good solution to the imperfections in these JB valves. Because the quality of JB valve standard system needs to be perfected, and there is no connection between each system, API valve standard overcomes these problems. For example, API600, API602, API598 and other standards, such as valve structure, component structure, component materials, Valve strength and tightness tests have made specific provisions, making the implementation of standards between users and manufacturers are almost the same, in order to ensure the overall quality of the valve. In particular, API valve is certified by the relevant quality certification body, so its quality has been guaranteed. This certification for our valve manufacturer is very necessary and effective.
1.2 API valve has a more complete structure JB valve gate, bracket structure and structure of the length of the need to some extent improved. The API valve in the structural design has been close to perfect, a relatively short API valve structure makes the valve takes up less space, while reducing the weight of the valve. API valve will generally use the elastic gate structure, because it can be adjusted with the valve seat with the model, a good seal to fundamentally reduce the leakage. In addition, the elastic shutter will prevent the occurrence of jamming caused by over tightening or thermal expansion. The perfect structural design of API valve just solved these problems rightly, the structure of API valve is more reasonable, the operation is extremely convenient, it has a lot of optional range, and the problem of large internal leakage and leakage is well solved , These superior structural design makes the life of API valves longer. It is precisely because of the incomparable superiority of the API structure, which has gradually become the main reference for other valve performance optimization.
It is worth pointing out that the structural design of foreign API valves is more optimized relative to our country, both in terms of structure size, operation method, optional range, service life, or to solve the internal leakage and leakage problems, have reached the fault-finding The point, if direct use of foreign API valve, many industrial enterprises will reduce the lot of valve repair and maintenance processes and costs. However, the long-term use of imported valves will waste a lot of money, although reducing the cost of valve repair and maintenance, but a large number of procurement of the valve will enable businesses to significantly increase the cost of costs. Therefore, in order to enable enterprises to use the valve with better performance under the condition of low cost, the related research enterprises of API valve in China should learn from the advantages of the foreign API valve structure design. According to the relevant situation of the valve enterprises in our country and the valve required by the enterprise The size of the structure, operating characteristics, tailor-made to design for them to use the API valve, in order to save costs, but also to make our country's API valve technology even more superb.
2 GB valve promotion and application issues GB valve standard was first introduced in 1989 in 1989, its content and structure have borrowed the characteristics of API standards, therefore, GB valve valve in the field of valve terms more advanced. However, the promotion and application of this standard is extremely limited. There are several reasons why the standard has not been widely popularized. First, the scope of production and application of API valves in China is very large. Many valve factories have their own smelting equipment, ASTM API material used in the valve, so stand in the perspective of manufacturers and users to analyze, and then take the time and effort to produce and use GB valve, not as good as before the API valve, saving time and effort, quality is also guaranteed. Second, the corresponding GB flange valve is a large diameter series, so the series of small diameter pipe can not be used at the same time GB and JB valve temperature and pressure curves are independent of each other and vary, making the compatibility of the two The process is difficult. So, if the JB valve manufacturing quality is decent, manufacturers and users will choose JB valve, in order to save a lot of trouble. Third, there are flaws in the GB valve standard system. Such as the GB valve using GB9131 provisions of the temperature and pressure curves, and GB9131 listed in the material is not much, and not the same as the ANSI or API standards casting materials will be listed, it can not be used in accordance with. Fourth, GB valve standard system has yet to adjust and promote, at the same time with the large diameter (SH) series and small diameter (JB) series compatibility. It is best to replace the currently used JB and API valves with GB valves.
3 metal seal butterfly valve applications At this stage, many domestic and foreign valve manufacturers in order to better meet the needs of large-scale petrochemical plant, have begun to study the metal seal butterfly valve and the production is to enable it to replace some of the valve. Metal seal butterfly valve shown in Figure 1. Some manufacturers from the butterfly valve structure and sealing efforts, such as double eccentric and three eccentric structure of the application, use a lot of ways to solve the butterfly valve in the event of wear and tear under high temperature problems. However, the application of metal hard sealing butterfly valve is still in its infancy, there is no relevant experience for support. In this regard, I hope the relevant state departments or authorities to existing products for technical analysis and performance testing, given the scope and conditions of the application of conclusions to ensure that the correct application.
Figure 1 metal seal butterfly valve 4 Application of high pressure hydrogenation valve Hydrogenation is an important method of deep processing of crude oil, so the process is particularly important. Therefore, our country's various refinery chemical plants will be equipped with the corresponding hydrogenation unit. However, many high-pressure valves used in the large hydrocracking units of many manufacturers are purchased from abroad. The number of these high-pressure valves is small but the price is very high. Under normal circumstances, the foreign valve is the same price of the domestic valve about 4 times, so in the domestic production of high pressure hydrogenation valve is necessary. Many of China's valve manufacturers, both from the equipment or technically have produced the level of the valve, and some products have been used on the hydrogenation unit. Manufacturers should also further improve their manufacturing capabilities and production levels, to create a qualified hydrogenated valve instead of imported valves. If the mass production of hydrogenation valve can meet the needs of hydrogenation device construction cycle to ensure that the product has the use of function, you can set up relevant departments under the relevant departments to the domestic high-pressure hydrogenation valve and petrochemical plant special Valves for research.
5 Conclusion In summary, the application of petrochemical plants in industrial valves there are still some problems to be solved, the domestic valve manufacturers should be more reference and learn from the successful experience of foreign excellent valve manufacturers, combined with the special valve business in China From the actual situation, guided by the needs of customers, we design and manufacture valves that are more suitable for the use of industrial enterprises in China and strive to improve the valve manufacturing level to provide users with more efficient and suitable products.
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