Features and installation precautions of gate valves
A gate valve is a valve in which the closing element (valve disc) moves along the centerline of the valve seat. Due to this movement of the valve disc, the change in the valve seat opening is directly proportional to the valve disc stroke. Because this type of valve has a relatively short stem opening or closing stroke and a very reliable shut-off function, and because the change in the valve seat opening is directly proportional to the valve disc stroke, it is very suitable for flow regulation. Therefore, this type of valve is ideal for shut-off, peraturan, and throttling applications.
The following points should be noted for the installation and maintenance of gate valves:
1. Gate valves operated by handwheels or handles can be installed in any position on the pipeline.
2. Handwheels, handles, and actuators are not permitted to be used for lifting.
3. The flow direction of the medium should be consistent with the arrow direction shown on the valve body.
Advantages of Gate Valves:
1. Simple structure, easy to manufacture and maintain.
2. Short working stroke, short opening and closing time.
3. Good sealing performance, low friction between sealing surfaces, and long service life.
Disadvantages of Gate Valves:
1. High fluid resistance, requiring greater force to open and close.
2. Not suitable for media containing particles, high viscosity, or prone to coking.
3. Poor regulating performance.
Types of Gate Valves: According to the position of the valve stem thread, there are external thread type and internal thread type. According to the flow direction of the medium, there are straight-through type, direct-flow type, and angle type. According to the sealing method, there are packing seal gate valves and bellows seal gate valves. Structure and Installation Precautions:
Structural Forms of Gate Valves: Gate valve bodies have the structural forms of straight-through, direct-flow, and right-angle types. The straight-through type is the most common structure, but it has the greatest fluid resistance. The direct-flow type has lower fluid resistance and is mostly used for fluids containing solid particles or with high viscosity. Right-angle valve bodies are mostly forged and are suitable for gate valves with smaller flow rates and higher pressures.
