The installation method and principle of cast steel valve are also mentioned more or less in the front. After installation of cast steel valve, regular inspection should be carried out, and main inspection items :(1) wear condition of sealing surface. (2) trapezoidal thread wear of cast steel valve stem and stem nut. (3) whether the packing is out of date or not, and should be replaced in time if there is any damage. (4) sealing performance test shall be conducted after valve overhaul and assembly. So what's the problem in the market?

1. Some operators purchase valves without factory name and print famous brands and certificates of well-known manufacturers, which seriously damage the reputation of qualified valve enterprises.

2. Some operators have repainted the old valve and sold it for the second time, bringing serious safety risks to the project quality.

The development trend of cast steel valves with the transfer of petroleum development to inland and offshore oilfields, and the development of electric power industry from less than 300,000 kw thermal power to more than 300,000 kw thermal power, hydropower and nuclear power, valve products should also change their performance and parameters according to the changes in equipment application fields. The urban construction system generally adopts a large number of low-pressure valves and develops to an environment-friendly and energy-saving type, that is, from the low-pressure iron gate valve used in the past to the environment-friendly glue plate valve, balance valve, metal seal butterfly valve and middle line seal butterfly valve. Oil and gas transmission projects develop towards pipeline, which requires a large number of flat gate valves and ball valves.

It can be seen that cast steel valves still have a good development trend in the market, but to avoid risks, and to maintain, this is a knowledge.

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