Development history of butterfly valve
In the 1930s, the United States invented the butterfly valve, which was introduced to Japan in the 1950s. It was only widely adopted in Japan in the 1960s, and its promotion in China was after the 1970s. The main features of butterfly valves are: small operating torque, small installation space and light weight. Taking DN1000 as an example, the butterfly valve is about 2T, and the gate valve is about 3.5T. The butterfly valve is easy to combine with various driving devices, and has good durability and reliability. The disadvantage of the rubber seal butterfly valve is that when it is used for throttling, it will cause cavitation due to improper use, which will cause the rubber seat to peel off and damage. Therefore, how to properly select it depends on the working conditions. The relationship between the opening degree of the butterfly valve and the flow rate basically changes linearly. If it is used to control the flow, its flow characteristics are also closely related to the flow resistance of the piping. For example, the valve diameter and form of the two pipeline installation valves are all the same, and the pipeline loss coefficient is different, and the flow rate of the valve will also be very different. If the valve is in a state of large throttling, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, it is used outside 15 °. When the butterfly valve is in the middle opening degree, the opening shape formed by the valve body and the front end of the butterfly plate is centered on the valve shaft, and the two sides are formed in different states. Therefore, one side of the valve body and the valve plate form a nozzle-like opening, and the other side is similar to a throttle-like opening. The nozzle side has a much faster flow rate than the throttle side, and a negative pressure is generated under the throttle side valve. The rubber seal may come off. The butterfly valve operating torque has different values due to different opening degrees and opening and closing directions of the valve. Horizontal butterfly valves, especially large-caliber valves, cannot be ignored due to the depth of the water. In addition, when an elbow is installed on the inlet side of the valve, a bias current is formed and the torque increases. When the valve is in the middle opening degree, the operating mechanism needs to be self-locked because of the water flow moment.
China's valve industry chain is numerous, but it is not a valve powerhouse. On the whole, China has entered the ranks of the world's valve powers, but from the perspective of product quality, there is still a long gap between China and the valve powers. The industry's low concentration of production, low R & D capabilities of valves supporting high-end products, and low manufacturing technology in the valve industry still exist, and the import and export trade deficit continues to expand. There are definitely not so many valve companies that can really survive the market. However, this high-speed shock of the valve industry will bring huge opportunities, and the results of the shock will make the market operation more rational. The localization of high-end valves is unusually bumpy. Basic parts have become a short board that restricts the development of high-end manufacturing in China. During the 12th Five-Year Plan period, the government will continue to increase the localization of high-end equipment components. Here we select a few key mentioned in the "implementation plan" to develop a representative valve industry for feasibility analysis of import substitution. It can be seen from the analysis that the feasibility of import substitution of valves in various sub-sectors is very different, and high-end valves need more policy guidance and scientific research support.
The valve industry plays a very important role in the development of the national economy as an important link in the equipment manufacturing industry. Due to the gap between China's domestic valve manufacturing level and the international advanced level, many key valves with high parameters, high temperature, high pressure and high pounds have always depended on imports. For example, the European OMAL brand has always been the main choice for domestic valve application industries. . In order to promote the localization of valves, after the State Council issued "Several Opinions on Accelerating the Revitalization of the Equipment Manufacturing Industry", the relevant state departments have made a series of major deployments in accordance with the national requirements for major equipment localization, and are led by the National Development and Reform Commission The China Machinery Industry Federation and the China General Machinery Industry Association have jointly formulated and formulated valve localization plans for major equipment in related fields, and coordinated with relevant departments on many occasions. Today, the localization of valves in the domestic valve industry has reached a consensus. Actively adopt international standards for product design; absorb excellent design structures (including patented technology) from abroad; product testing and performance testing are carried out in strict accordance with international standards; absorb foreign production process experience and attach importance to the research and promotion of new materials; clarify the high level of imports Parameter The technical parameters and working conditions of valve products are the way to speed up the localization process, promote the continuous updating of valve products, and fully realize the localization of valves. With the acceleration of the restructuring of the valve industry, the future industry will be competition between valve product quality and safety and product brands. The products will develop in the direction of high technology, high parameters, strong corrosion resistance, and long life. Only through continuous technological innovation and development New products and technical transformation can gradually improve the technical level of the product, meet the domestic equipment supporting, and fully realize the localization of the valve. China's valve manufacturing industry will present a better development prospect under the huge demand environment