What is a gate valve
Gate valves can only be used for full opening and full closing in pipelines; they cannot be used for regulating or throttling. Gate valves are widely used and are generally used for DN50 shut-off devices, though they are sometimes also used for smaller calibers. Gate valves are used to shut off media. When fully open, the entire flow is straight-through, minimizing pressure loss during media flow. Gate valves are typically suitable for applications where frequent opening and closing are not required and the gate must be kept fully open or closed. They are not suitable for regulating or throttling. For high-speed media, a partially open gate can cause vibration, which can damage the sealing surfaces between the gate and valve seat. Throttling can also cause erosion of the gate by the media.
What are the advantages of gate valves?
1. Low fluid resistance: Because the media passageway inside the gate valve body is straight, the media does not change its flow direction when flowing through the gate valve, resulting in low fluid resistance.
2. Low opening and closing torque: Opening and closing are less labor-intensive. Because the gate disc moves perpendicular to the media flow direction during opening and closing, gate valves require less effort to open and close than globe valves.
3. The media flow direction is unrestricted, without turbulence or pressure drop. The media can flow through the gate valve in either direction, achieving its intended purpose. It is particularly suitable for pipelines where the media flow direction may change.
4. Shorter overall length: Because the gate disc of a gate valve is vertically positioned within the valve body, while the disc of a globe valve is horizontally positioned within the valve body, the overall length is shorter than that of a globe valve.
5. Excellent sealing performance: When fully open, the sealing surface is subject to less erosion.
6. When fully open, the sealing surface is subject to less erosion by the working medium than a globe valve.
7. Relatively simple in shape, it offers excellent casting processability and a wide range of applications.
What are the disadvantages of gate valves?
1. The sealing surface is easily damaged.
During opening and closing, the gate disc and valve seat contact each other, causing relative friction and damage, which affects the performance and service life of the seal and makes maintenance difficult.
2. The opening and closing time is long and the height is high.
Since gate valves must be fully opened or closed when opening and closing, the gate disc has a large stroke and requires a certain amount of space for opening. The overall dimensions are tall, and the installation space required is large.
3. The structure is complex.
Gate valves generally have two sealing surfaces, which increases the processing, grinding, and maintenance requirements. They have more difficult parts, making them more difficult to manufacture and repair, and their cost is higher than that of globe valves.
