What is the difference between a ball valve and a plug valve?
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As the title suggests: Do ball valves and plug valves work on the same principle? What are their respective features?
When used for cutting off flow, plug valves offer slightly better control capabilities compared to ball valves, but this advantage is limited. Although plug valves have much larger sealing surfaces than ball valves, which results in better sealing, it also leads to higher torque and less flexibility in operation. A plug valve is a rotary valve with a closing element or plunger; it operates by rotating 90 degrees to align or separate the passage in the plug from the passage in the valve body, thereby enabling opening or closing. The shape of the plug in a stopcock can be cylindrical or conical. In cylindrical valve plugs, the channels are generally rectangular ； In a conical plug, the channel is trapezoidal. These shapes enable the plug
Ball valves and plug valves operate on a similar principle: one relies on the rotation of a spherical element, while the other uses a straight valve stem with holes on its surface; rotation of this stem to different positions is used to open or close the valve. Ball valves are divided into floating and fixed types, with the fixed type being more expensive, whereas plug valves are generally of the fixed type. If there is anything wrong, please point it out.
Also, the inner diameter of ball valves is larger, while that of plug valves is much smaller
In principle, a ball valve is also a type of special plug valve; the difference is that while the valve element in a regular plug valve is cylindrical or conical-cylindrical in shape, the valve element in a ball valve is spherical. Both types of valves maintain their sealing property by ensuring tight contact between the valve core and the sealing surface, and they both open the flow channel through the rotation of the valve core. If contaminants enter the valve core or sealing surfaces, the valve’s sealing performance will decline rapidly due to wear of those sealing surfaces.
In the cryogenic industry, ball valves are generally used; only Shell requires stopcocks for certain applications. Stopcocks ensure zero leakage, while ball valves have chambers and, as the experts mentioned earlier, can experience wear and tear. However, ball valves are much cheaper. Ball valve technology in China is also quite advanced. For example, the Apollo 7660357 model was used in almost all quick-cooling systems in China over the past 10 years, but now most of these systems use domestically produced ball valves. Domestic products offer advantages in terms of both technology and price. Yet, for materials such as acetate fiber, paint, and PTA, ball valves must not be used – stopcocks are required instead