Description
Overview
Among various types of valves, gate valves are the most widely used. API ASME Steel Pipe Flange Electric Gate Valve refers to a valve whose closing member (gate plate) moves along the vertical direction of the channel axis. It is mainly used to cut off the medium on the pipeline, that is, it is used fully open or fully closed. Generally, gate valves cannot be used to regulate flow. It can be applied to low temperature and low pressure as well as high temperature and high pressure, and can be used for various media according to different materials of the valve. However, intermediate valves are generally not used in pipelines transporting media such as mud. Gate valve has the following advantages:
① Small fluid resistance.
②The torque required for opening and closing is small.
③ It can be used on ring network pipelines where the medium flows in both directions, which means that the flow direction of the medium is not restricted. ④When fully open, the sealing surface is less eroded by the working medium than the stop valve.
⑤The body structure is relatively simple and the manufacturing process is good.
⑥The structure length is relatively short. Because gate valves have many advantages, they are used in a wide range of applications. Generally, gate valves are used as devices for cutting off the medium in pipelines with a diameter of ≥ DN50. Even on some small-diameter pipelines (such as DN15~DN40), some gate valves are still retained.
Gate valves also have some shortcomings, mainly:
①The overall size and opening height are large, and the required installation space is also large.
② During the opening and closing process, there is relative friction between the sealing surfaces, resulting in greater wear and tear, and even scratches at high temperatures.
③ Generally, gate valves have two sealing pairs, which adds some difficulties to processing, grinding and maintenance.
④The opening and closing time is long. Gate valves have various structural types. The main difference is the structural type of sealing elements used. According to the structure of the sealing element, gate valves are often divided into several different types, and the most common forms are parallel gate valves and wedge gate valves; according to the structure of the valve stem, it can also be divided into lifting stem (rising stem) and rotating stem (non rising stem) gate valve.
