1. Introduction to gate valves
Gate valve refers to the valve in which the opening and closing parts (rams) move in the straight direction of the medium (channel axis) to complete the opening and closing. Among the various types of valves, gate valves are the most widely used one.
The gate valve is mainly used as a shut-off medium on the pipeline, that is, it is fully open or fully closed, which can be applied to low temperature and low pressure and high temperature and high pressure, and can be used for a variety of different media according to the different materials of the valve.
2. Terminology of parts and components
The gate valve is mainly composed of valve body, valve cover, bracket, valve stem, valve stem nut, ram, valve seat, stuffing box, sealing packing, upper sealing seat, packing gland and transmission device and other parts.
3. Characteristics of gate valves
Low fluid resistance: the medium channel inside the valve body is straight, and the medium does not change its direction of activity when it flows through the gate valve.
The torque required for opening and closing is small; It can be used on a ring network pipe that moves in both directions, i.e., the flow direction of the media is not restricted.
The shape structure is relatively simple, and the manufacturing process is good. Good sealing performance: the sealing surface is less eroded when fully opened.
4. Defects of gate valves:
The required opening and closing time is long, the overall size and opening height are large, and the space of the device is large. It takes a long time to turn on or off.
When opening and closing, there is a relative conflict between the sealing surfaces, and the wear is large, and even at high temperatures, it is easy to cause abrasion.
Generally, gate valves have two sealing pairs, which adds some difficulties to processing, grinding and maintenance.
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