几大阀门的结构原理（The structure principle of several big valves）.doc

几大阀门的结构原理（The structure principle of several big valves） 1. gate valve? Gate valve, also called gate valve, is a widely used valve. Its closing principle is that the gate sealing surface and the valve seat sealing surface are smooth and smooth, and they fit together to prevent the flow of the medium, and rely on the die shape of the top die, spring or gate to enhance the sealing effect. It mainly cuts off in the pipeline. ???? It has the following advantages: fluid resistance small, open and close, strength, can be used in the two-way flow of media under the condition of no direction, full sealing surface is not easy to erosion, short length of the structure, not only suitable for small valves, but also suitable for bigger valves. Gate valve in accordance with the valve thread into two categories, one is bright rod, and two is dark rod type. According to the gate structure, there are two kinds, one is parallel, the other is mode two. ???? 2. valve???? stop valve, also called the door, is the most widely used as a valve, it is popular is because the process of opening and closing the sealing surface friction between the small, more durable, highly open small, easy manufacture, convenient maintenance, not only suitable for low pressure. It is suitable for high voltage. Its closure principle is to rely on the valve bar pressure, so that the valve sealing surface and seat sealing surface close together, to prevent the circulation of media. ???? Medium one-way valve can only flow direction when installing. Its structure length is larger than gate valve, and the fluid resistance is large. The reliability of sealing is not strong in long-term operation. There are three kinds of stop valve: straight through type, right angle type and direct current type oblique stop valve. 3. butterfly valves? Butterfly valves, also known as butterfly valves. As the name suggests, the key components of the butterfly valve are the butterfly, the wind and the free swing. Butterfly valve disc