As the valve has a wide range of application fields and medias, and with different corrosion conditions, that’s why the service life time of the valve has not been stipulated from National & Industry standards.
In 1980, in order to improve the quality of machinery industry products and cooperate with national high-quality product evaluations, the Ministry of Machinery Industry formulated the “Regulations for Product Quality Classification in the Valve Industry.” Among them, the requirements of lifetime test are stipulated for gate valve and globe valve. For example, for the valves from Dn ≤ 200 to 400, the number of scratch resistance is 2,000 to 4,000.
There are two ways to indicate the service life of foreign valves: One is the service life and the other is the number of switching times.
Due to the particularity of nuclear power plants, countries have stipulated the service life of nuclear power valves; valves used in the nuclear industry are expressed by the service life, the general life time is 30 ~ 40 years, the guarantee life time of United States and Germany nuclear power valve is 40 years, the United Kingdom is 30 years, Japan is 30 ~ 40 years.
The service life of a valve is generally expressed by the switching times. Due to the different conditions of using and test methods, the switching times does not necessarily indicate the life time of the valves. Unless the working conditions are the same, and the use or test method is same as well.
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