Let’s talk about butterfly valves

Butterfly valves can be used for regulation, but their regulating performance is not as good as that of single-seat and sleeve valves; however, their advantage is that they can be manufactured in large diameters. The greatest advantage of butterfly valves as on-off valves is that they can be manufactured in large diameters, and they are relatively easy to install. The downside is that their shut-off performance and sealing performance are not as good as those of ball valves and gate valves. Butterfly valves are not very suitable, especially in applications with large pressure differences.

Butterfly valve: The operating element of a butterfly valve is a disc-shaped butterfly plate that rotates around its own axis within the valve body, thereby enabling the valve to be opened, closed, or adjusted. It is primarily used in large-diameter pipelines, such as those for circulating water and utility systems 2. The fluid resistance is lower than that of a globe valve! 3. The weight is much lower compared to gate valves, globe valves, and ball valves! 4. Its regulating performance is not as good as that of a globe valve! 5. The sealing isn’t very reliable! The sealing types of butterfly valves can be divided into soft-sealing and hard-sealing types. The soft-sealing type generally uses rubber rings for sealing, while the hard-sealing type typically uses metal rings for sealing.

The operating element of a butterfly valve is a disc-shaped butterfly plate that rotates around its own axis within the valve body, thereby enabling the valve to be opened, closed, or adjusted. Such a valve is called a butterfly valve. The rotation range of a butterfly valve from fully open to fully closed is usually less than 90 degrees. The butterfly valve and its shaft do not possess sufficient self-locking capability; therefore, a worm gear reducer must be installed on the shaft in order to position the butterfly disc. The use of a worm gear reducer not only enables the butterfly valve disc to have self-locking capability, allowing it to remain in any position, but also improves the operating performance of the valve. 　　Industrial butterfly valves are characterized by their ability to withstand high temperatures, a wide pressure range, a large nominal diameter. The valve body is made of carbon steel, and metal rings are used as seals for the valve disc instead of rubber rings. Large high-temperature butterfly valves are manufactured by welding steel plates, and are primarily used in flue gas ducts and gas pipelines handling high-temperature media. Advantages of butterfly valves: 1. Easy and rapid opening and closing, low effort required, minimal fluid resistance, allowing for frequent operation. 2. Simple structure, small size, and light weight. 3. It can transport mud, with minimal liquid accumulation at the pipe outlet. 4. Good sealing can be achieved at low pressures. 5. It has good regulation performance. Disadvantages of butterfly valves: 1. Narrow range of operating pressure and temperature. 2. Poor sealing performance. 　　Butterfly valves can be classified by structure into offset plate type, vertical plate type, inclined plate type, and lever type. Based on the sealing type, they can be divided into the semi-sealed type and the hard-sealed type. Soft-sealed types generally use rubber rings for sealing, while hard-sealed types usually use metal rings for sealing. 　　Based on the type of connection, they can be divided into flange connections and clamp connections ； Based on the transmission method, they can be classified into manual, gear-driven, pneumatic, hydraulic, and electric types. The following points should be noted for the installation and maintenance of butterfly valves: 1. During installation, the valve disc must be in the closed position. 2. The opening position should be determined based on the rotation angle of the butterfly valve. 3. For butterfly valves equipped with a bypass valve, the bypass valve should be opened first before turning on the valve. 4. Installation shall be carried out in accordance with the manufacturer’s installation instructions; for butterfly valves with heavy weights, a solid foundation must be provided. Hydraulic control valves use the pressure of the medium in the pipeline itself as a power source for opening, closing, and regulating. By combining different configurations of pilot valves and smaller pipelines within the system, it is possible to achieve nearly 30 different functions; these valves are now being used more and more widely. The pilot valve operates in response to changes in the water level and pressure that are the objects of control. Since there are many types of pilot valves, they can be used alone or in combination, enabling the main valve to achieve separate or combined regulation of water level, water pressure, flow rate, and so on. However, the main valve is similar to a globe valve; when it is fully open, its pressure loss is much greater than that of other valves. Moreover, the loss coefficient increases sharply as the degree of opening approaches full closure, and this effect becomes more pronounced as the valve diameter increases. For valves with the aforementioned characteristics, as they approach full closure, the movement of the valve disc accelerates, which makes it prone to water hammer effects caused by pressure surges. The slower the valve moves as it approaches full closure, the better; therefore, a throttling mechanism can be installed on the valve disc. Furthermore, in the flow-restricting and actuating parts of the pilot valve, it is advisable to avoid using orifices with extremely small diameters to prevent blockages. A filter screen should be installed if necessary, and regular maintenance as well as the installation of bypass pipelines are required. The development and application prospects of this type of valve are promising. Working principle: Hydraulic control valves are divided into diaphragm type and piston type. The main components include a main valve along with associated components such as conduits, pilot valves, needle valves, ball valves, and pressure gauges. It uses the pressure difference between the upstream and downstream areas as power. Controlled by a pilot valve, when the pressurized water in the control chamber above the diaphragm piston is discharged to the atmosphere or a lower-pressure area downstream, the pressure acting on the bottom of the valve disc and below the diaphragm becomes greater than the pressure above, thereby pushing the main valve disc to its fully open position. When the pressure in the control chamber above the diaphragm piston cannot be discharged to the atmosphere or a lower-pressure area downstream, the pressure acting on the upper side of the diaphragm piston becomes greater than the pressure below, which pushes the main valve disc to its fully closed position. When the pressure in the control chamber above the diaphragm piston is somewhere between the inlet pressure and the outlet pressure, the main valve disc is in a regulating state, with its position determined by the combined action of the needle valve and the adjustable pilot valve in the piping system. The adjustable pilot valve can utilize the downstream outlet pressure and adjust its own small valve orifice to open or close in response to changes in that pressure, thereby changing the pressure level in the control chamber above the diaphragm piston and controlling the adjustment position of the main valve’s disc. The operating element of a butterfly valve is a disc-shaped butterfly plate that rotates around its own axis within the valve body, thereby enabling the valve to be opened, closed, or adjusted. Such a valve is called a butterfly valve. The rotation range of a butterfly valve from fully open to fully closed is usually less than 90 degrees. The butterfly valve and its shaft do not possess sufficient self-locking capability; therefore, a worm gear reducer must be installed on the shaft in order to position the butterfly disc. The use of a worm gear reducer not only enables the butterfly valve disc to have self-locking capability, allowing it to remain in any position, but also improves the operating performance of the valve. 　　Industrial butterfly valves are characterized by their ability to withstand high temperatures, a wide pressure range, a large nominal diameter. The valve body is made of carbon steel, and metal rings are used as seals for the valve disc instead of rubber rings. Large high-temperature butterfly valves are manufactured by welding steel plates, and are primarily used in flue gas ducts and gas pipelines handling high-temperature media. Advantages of butterfly valves: 1. Easy and rapid opening and closing, low effort required, minimal fluid resistance, allowing for frequent operation. 2. Simple structure, small size, and light weight. 3. It can transport mud, with minimal liquid accumulation at the pipe outlet. 4. Good sealing can be achieved at low pressures. 5. It has good regulation performance. Disadvantages of butterfly valves: 1. Narrow range of operating pressure and temperature. 2. Poor sealing performance. 　　Butterfly valves can be classified by structure into offset plate type, vertical plate type, inclined plate type, and lever type. Based on the sealing type, they can be divided into the semi-sealed type and the hard-sealed type. Soft-sealed types generally use rubber rings for sealing, while hard-sealed types usually use metal rings for sealing. 　　Based on the type of connection, they can be divided into flange connections and clamp connections ； Based on the transmission method, they can be classified into manual, gear-driven, pneumatic, hydraulic, and electric types. The following points should be noted for the installation and maintenance of butterfly valves: 1. During installation, the valve disc must be in the closed position. 2. The opening position should be determined based on the rotation angle of the butterfly valve. 3. For butterfly valves equipped with a bypass valve, the bypass valve should be opened first before turning on the valve. 4. Installation shall be carried out in accordance with the manufacturer’s installation instructions; for butterfly valves with heavy weights, a solid foundation must be provided.

The introduction is very comprehensive; it’s a shame I don’t have the authority to rate it, otherwise I would give 10 points. Just pay attention to the formatting next time, as there is repeated content