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There are many types of valves, each with its own advantages and disadvantages. Below, the editor lists the pros and cons of five main types of valves: gate valves, butterfly valves, ball valves, globe valves, and plug valves. Hopefully, this information will be useful to you. Gate valve: A gate valve is a type of valve in which the closing element (gate) moves vertically along the axis of the passage; it is primarily used in pipelines to shut off the flow of medium, that is, to operate in either fully open or fully closed position. Generally, gate valves cannot be used to regulate flow. It can be used in low-temperature and low-pressure conditions as well as in high-temperature and high-pressure conditions, and it can be adapted to different valve materials. However, gate valves are generally not used in pipelines for transporting media such as slurry. Advantages: ① Low fluid resistance; ② Small torque required for opening and closing; ③ Can be used in loop pipelines where the medium flows in both directions, meaning the flow direction of the medium is not restricted; ④ When fully open, the sealing surface is subject to less erosion by the working medium compared to globe valves; ⑤ The structural design is relatively simple, making it easy to manufacture; ⑥ The overall length of the structure is relatively short. Disadvantages: ① It has large external dimensions and opening height, requiring more space for installation; ② During the opening and closing process, relative friction occurs between the sealing surfaces, leading to significant wear, and scratches may even occur at high temperatures; ③ Most gate valves have two sealing surfaces, which adds complexity to processing, grinding, and maintenance; ④ The time required for opening and closing is long. Butterfly valve: A butterfly valve is a type of valve that uses a disc-shaped closing element to rotate back and forth by about 90° in order to open, close, or regulate the flow of fluid. Advantages: ① Simple structure, small size, light weight, and low consumption of materials; not suitable for large-diameter valves; ② Fast opening and closing, with low flow resistance; ③ Can be used with media containing suspended solid particles, and depending on the strength of the sealing surface, it can also be used with powdered and granular media. It is suitable for bidirectional opening/closing and regulation of ventilation and dust removal pipelines, and is widely used in gas pipelines and water channels within metallurgy, light industry, power, and petrochemical systems. Disadvantages: ① The flow rate regulation range is limited; when it is set at 30%, the flow rate exceeds 95%. ② Due to the structure of the butterfly valve and the limitations of the sealing materials, it is not suitable for use in high-temperature and high-pressure pipeline systems. The typical operating temperature is below 300°C, with a pressure rating below PN40. ③ Its sealing performance is inferior to that of ball valves and globe valves; therefore, it is used in applications where sealing requirements are not very stringent. Ball valve: The ball valve evolved from the plug valve; its operating element is a sphere, and opening and closing are achieved by rotating this sphere 90° around the axis of the valve stem. Ball valves are primarily used on pipelines to shut off, distribute, and change the direction of fluid flow; those designed with a V-shaped opening also possess excellent flow regulation capabilities. Advantages: ① It has the lowest flow resistance (actually 0); ② It does not get stuck during operation (without lubricant), allowing it to be used reliably in corrosive media and low-boiling-point liquids; ③ It provides a complete seal over a wide range of pressures and temperatures; ④ It enables fast opening and closing – the opening/closing time for some designs is only 0.05–0.1 seconds, which ensures its suitability for use in automated systems on test benches. When the valve is opened and closed quickly, the operation is shock-free; ⑤ The spherical closing element can automatically position itself at the boundary position; ⑥ The working medium is reliably sealed on both sides; ⑦ When the valve is fully open or fully closed, the sealing surfaces of the sphere and the valve seat are separated from the medium, so the medium flowing through the valve at high speeds does not cause erosion of these sealing surfaces; ⑧ It has a compact structure and low weight, making it the most suitable valve design for systems using low-temperature media; ⑨ The valve body is symmetrical, and especially in the case of welded valve bodies, it can effectively withstand stresses from the pipes; ⑩ The closing element can handle high pressure differences during closure. ⑾Ball valves with fully welded valve bodies can be buried directly underground, preventing the internal components of the valve from being corroded; their maximum service life can reach 30 years, making them the ideal valves for oil and gas pipelines. Disadvantages: ① Since the main material used for the seat seal ring in ball valves is polytetrafluoroethylene, it is inert to almost all chemicals. It also boasts a low friction coefficient, stable performance, resistance to aging, a wide temperature range of operation, and excellent sealing properties. However, the physical properties of polytetrafluoroethylene, including its high coefficient of expansion, sensitivity to cold flow, and poor thermal conductivity, require that the design of the valve seat seal take these properties into account. Therefore, when the sealing material hardens, the reliability of the seal is compromised. Moreover, polytetrafluoroethylene has a low temperature resistance and can only be used at temperatures below 180°C. Above this temperature, the sealing material will age. When considering long-term use, it is generally not used at 120°C. ②Its regulating performance is somewhat inferior to that of globe valves, especially pneumatic valves (or electric valves). Globe valve: A globe valve is a type of valve in which the closing element (valve disc) moves along the center line of the valve seat. Based on this type of movement of the valve disc, the change in the valve seat opening is directly proportional to the stroke of the valve disc. Due to the relatively short opening and closing stroke of the valve stem in this type of valve, as well as its highly reliable shut-off function, and because the change in the valve seat orifice is proportional to the stroke of the valve disc, it is very suitable for regulating flow rate. Therefore, this type of valve is very suitable for use in cutting off or regulating flow, as well as for throttling. Advantages: ① During opening and closing, the frictional force between the valve disc and the sealing surface of the valve body is lower than that of gate valves, thus it is more wear-resistant. ②The opening height is generally only 1/4 of the valve seat passage, making it much smaller than gate valves; ③ There is usually only one sealing surface on the valve body and the valve disc, which facilitates manufacturing and makes maintenance easier; ④ Since its packing is typically a mixture of asbestos and graphite, it has a high temperature resistance rating. Gauge valves are generally used for steam valves. Disadvantages: ① The minimum flow resistance of globe valves is higher than that of most other types of valves, as the direction of fluid flow through the valve changes; ② Due to their longer stroke, they open more slowly than ball valves. Plug valve: A plug valve is a rotary valve whose closing element is in the form of a plunger; it operates by rotating 90° to connect or separate the passage in the plunger from the passage in the valve body, thereby enabling opening or closing. The shape of the valve plug can be cylindrical or conical. Its principle is basically similar to that of a ball valve, which was developed from a plug valve. It is primarily used in oil field extraction, as well as in the petrochemical industry. Advantages: 1. Suitable for frequent use, with quick opening and closing and is lightweight. 2. Low fluid resistance. 3. Simple, with a relatively small volume and light weight, making it easy to maintain. 4. Good sealing performance. 5. Limited by the installation direction, the flow direction of the medium can be arbitrary. 6. No vibration, low noise. Disadvantages: 1. The cover is too large, resulting in excessive torque and a lack of flexibility. 2. The body weight has an impact, and the caliber size is limited. 3. In practical use, if large-sized valves are employed, a reverse plug structure must be used, which can easily affect the sealing performance.