The plug valve uses a plug with a through hole as a valve for the opening and closing parts. The cock rotates with the valve stem to realize the opening and closing action. Small unpacked plug valves are also known as "cocks". The plug of the plug valve is mostly a cone (also a cylinder). It cooperates with the conical hole surface of the valve body to form a sealing pair. The plug valve is the earliest type of valve. The plug valve has a simple structure, small external dimensions, fast opening and closing, and small fluid flow resistance, but the sealing surface is processed and maintenance is more difficult. The ordinary plug valve is sealed by the direct contact between the finished metal plug body and the valve body, so the sealing performance is poor, the opening and closing force is large, it requires a large rotating torque, and it is easy to wear. Usually only used for low pressure (<1MPa), small diameter (<100mm) and low temperature (<150 degrees Celsius). It is not suitable for high temperature. When the temperature changes greatly, it is easy to get stuck.
1. The plug valve is used for frequent operation, and it opens and closes quickly and easily.
2. The fluid resistance of the plug valve is small.
3. The plug valve is simple in structure, relatively small in size, light in weight, and easy to maintain.
4. Not limited by the installation direction, the flow direction of the medium can be arbitrary.
5. No vibration and low noise.
The plug valve, also known as the swivel door, is a quick-opening valve. According to its shunt situation, it is divided into straight-through type, three-way type, four-way type and so on. The straight-through type controls the flow of the medium on the straight pipe section, and the three-way type and the four-way type can be used to distribute the medium and change its flow direction. The working principle of the cock is that the cock body rotates around the center line of the valve body, and the purpose of opening and closing is achieved by the corresponding relationship between the port on the cock body and the ports at both ends of the valve body. The advantage of the cock is that it is easy to operate, open and close quickly, the resistance is small, the flow rate is large, the structure is simple, and the external dimension is small; The valve core may be deformed at high temperature and easily stuck at high temperature and high pressure.
The plug valve is mostly used for medium with lower temperature, and is often used in:
1. The pipeline needs to be fully opened and fully closed quickly.
2. Low pressure container liquid level indicator.
3. Places that are not frequently operated or used as inspections.