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Reduced diameter ball valves and full-bore ball valves
Ball valve is currently the most widely used mechanical product in all valve markets, which is mainly composed of valve body, valve seat, ball, valve stem and transmission device, and drives the ball core rotation through the actuator to achieve the function of switching or adjustment. It is widely used in petrochemical, water conservancy, urban construction, heat and other industries.
There are many types of ball valves, through the different structural forms, connection methods, pressure levels, drive forms, etc., can be combined into a variety of products with different functions, but from the most basic, ball valves have full-diameter ball valves and reduced diameter ball valves two categories of difference, in general, the inner diameter of the valve ball is less than or equal to 85% of the inner diameter of the ball valve port, that is, it is called reduced diameter ball valve and ball valve inner diameter is greater than 95% of the inner diameter of the ball valve port, it is called full-diameter ball valve.
01 Definitions
1. The full-bore ball valve is an equal-width flow channel, that is to say, the size of the hole from the flow in to the outflow is the same, and its size cannot be less than the value specified in the standard, which is probably equivalent to the nominal diameter of the specification, such as DN50 full-bore ball valve flow channel diameter also needs to be about 50;
2. The inlet of the flow channel of the reduced diameter ball valve is wider than the diameter of the flow channel, and the actual diameter of the flow channel is about one specification smaller than the specification, such as DN50 reduced diameter ball valve flow channel diameter is about 38, which is roughly equivalent to the specification of DN40. In DN250 and within one specification, 250-600 shrink two specifications, 600 above according to the actual situation.
02 Media
1. Full-diameter ball valve is generally used to transport viscous, easy to slag medium pipeline, because of its small fluid resistance, it can be said that there is basically no flow resistance, which can facilitate the regular scraping wax purge through.
2. The reduced diameter ball valve is suitable for transporting gas or medium with physical properties similar to water, because its weight is about 30% lighter than the full-diameter ball valve, and its flow resistance layer has about 1/7 of the same caliber globe valve. It is beneficial to reduce the load on pipelines and reduce costs.
03 Process
1. For pipelines that need to be regularly pigged, no matter what medium is transported, full-diameter ball valves must be used. The medium passing through the full-bore ball valve will not reduce the flow, and the flow resistance is small, which is an ideal product for pipeline control, especially under strict working conditions, especially when the main line in the oil pipeline and gas pipeline needs to be buried underground, the full-bore welded ball valve must be used.
2. Reduced diameter ball valve is suitable for some working conditions such as low requirements and small convection resistance requirements, when the inner diameter of the valve is greater than 80% of the inner diameter of the pipe end, it has almost no impact on the pipeline fluid passing capacity. Many shutters have a reduced diameter, generally controlled within 0.8, the diameter reduction on the one hand reduces the flow capacity of the valve, that is, the K value of the valve, increases the pressure on both sides of the valve, resulting in the loss of energy, for the pipeline, there is not much impact, may increase the scouring of the pipeline.
