Gate vavle
The opening and closing part of the gate valve is the gate, and the movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled.
Advantages of gate valve: ① The fluid resistance is small, and the sealing surface is less brushed and eroded by the medium. ②It is more labor-saving to open and close. ③The flow direction of the medium is not restricted, the flow is not disturbed, and the pressure is not reduced. ④ The shape is simple, the structure length is short, the manufacturing process is good, and the application range is wide.
Disadvantages of gate valve: ① It is easy to cause erosion and scratches between the sealing surfaces, and it is difficult to maintain. ②The external size is large, a certain space is required to open, and the opening and closing time is long.
Globe vavle
The opening and closing parts of the globe valve are plug-shaped discs, the sealing surface is flat or conical, and the disc moves in a straight line along the center line of the fluid. It is stipulated in the "Three Chemicals" of our country's valves that the flow direction of the globe valve shall be all automatic top down.
The advantages of the globe valve: ① The structure is simple, and the manufacture and maintenance are more convenient. ②The working stroke is small, and the opening and closing time is short. ③Good sealing performance, small friction between sealing surfaces and long service life.
Disadvantages of the globe valve: ① The fluid resistance is large, and the force required for opening and closing is large. ②Not suitable for media with particles, high viscosity and easy coking.
Check vavle
The opening and closing parts of the check valve are automatically opened or closed by the flow and force of the medium to prevent the backflow of the medium. The check valve belongs to the automatic valve category, which is mainly used on the pipeline where the medium flows in one direction, and only allows the medium to flow in one direction to prevent accidents. According to the structure, check valves can be divided into three types: lift check valves, swing check valves and butterfly check valves.
Ball vavle
The ball valve is a valve that uses a ball with a circular channel as the opening and closing part, and the ball rotates with the valve stem to realize the opening and closing action. The opening and closing part of the ball valve is a ball with a hole, which rotates around the axis perpendicular to the channel, so as to achieve the purpose of opening and closing the channel.
Advantages of ball valve: ①Suitable for frequent operation, quick and easy opening and closing. ②The fluid resistance is small. ③ Simple structure, relatively small size, light weight, easy maintenance. ④Good sealing performance. ⑤It is not limited by the installation direction, and the flow direction of the medium can be arbitrary. ⑥No vibration and low noise.
Butterfly vavle
The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body, so that the valve that can be opened, closed or adjusted is called a butterfly valve. The butterfly valve is usually less than 90° from fully open to fully closed. The butterfly valve and the butterfly stem themselves do not have self-locking force. In order to locate the butterfly plate, a worm gear reducer should be installed on the valve stem. The use of worm gear reducer can not only make the butterfly plate have self-locking ability, so that the butterfly plate can stop at any position, but also improve the operation performance of the valve.
The characteristics of the industrial butterfly valve are high temperature resistance, high applicable pressure range, large nominal diameter of the valve, carbon steel for the valve body, and metal ring instead of rubber ring for the sealing ring of the valve plate. Large high temperature butterfly valve is made of steel plate welding, mainly used for flue air duct and gas pipeline of high temperature medium.
