Classification and characteristics of gate valves
Gate valves are widely used in pipelines, mainly to connect and cut off the role of the medium.Not suitable for regulating the flow of the medium, but can be used to determine the flow based on the height of the valve stem lift (such as fire protection resilient seat seal gate valve with opening and closing scale).Gate valves, compared with other valves, the pressure, temperature, diameter and other requirements of the application of a wide range.
Gate valves can be divided into wedge type single gate type, elastic gate type, double gate type, parallel gate type according to the different internal structure.
According to the different stem support can be divided into: open stem gate valve and dark stem gate valve.
Main performance advantages of gate valves:
1. The valve fluid resistance is small, because the gate valve body is straight, the medium flow does not change the direction, so the flow resistance is smaller than other valves;
2. The sealing performance is better than the globe valve, opening and closing is also better than the globe valve labor saving;
3. Wide range of applications, in addition to steam, oil and other media, but also suitable for containing granular solids and viscosity of the medium, also suitable for vent valve and low vacuum system valves to use;
4. Gate valves are double-flow valves, which are not limited by the flow direction of the medium, so they are suitable for pipes where the medium may change the flow direction, and are also easy to install.
Main performance disadvantages of gate valves:
1. High shape design size, long opening and closing time.When the valve is opened, it is necessary to lift the valve plate to the upper part of the valve cavity; when it is closed, it is necessary to drop all the valve plate into the seat.
2. Due to the friction between the valve plate and the valve seat during the opening and closing process, the sealing surface is easy to scratch, which affects the sealing performance and service life, and is not easy to repair.