Pneumatic ball valve is a common control component that changes through a plug valve. The difference is that the plug valve is circular in shape and has a circular opening through its axis. So what is the purpose of pneumatic ball valve? What is the structure?
1、 Purpose
The working principle of pneumatic ball valves is to rotate the valve core to make the valve unobstructed or blocked. Pneumatic ball valves are lightweight, small in size, can be made into large diameters, reliable in sealing, simple in structure, and easy to maintain. The sealing surface and spherical surface are often in a closed state and are not easily corroded by the medium. They are widely used in various industries.
Pneumatic ball valve and plug valve belong to the same type of valve, with only its closing part being a sphere. The sphere rotates around the centerline of the valve body to achieve opening and closing
Pneumatic ball valves are mainly used in pipelines for fast cutting speed, distribution, and changing the flow direction of the medium
2、 What is the structure?
1. Floating pneumatic ball valve
The ball of pneumatic ball valve is floating, and under the pressure of the medium, the ball can produce a certain displacement and tightly press on the sealing surface of the outlet end, ensuring the sealing of the outlet end. The floating pneumatic ball control valve has a simple structure and good sealing performance, but the ball bears all the load of the working medium and is transmitted to the outlet sealing port. Therefore, it is necessary to consider whether the sealing material can withstand the working load of the spherical medium. This structure is widely used for medium and low pressure ball valves.
2. Fixed ball pneumatic ball valve
The ball of a pneumatic ball valve is fixed and does not move under pressure. Fixed ball deficient trees are equipped with floating valve seats. When subjected to medium pressure, the valve seat moves, causing the seal to be tightly placed on the ball to ensure sealing. Usually, it is
The upper and lower shafts of the sphere are equipped with bearings, which have small pitch and are suitable for high-pressure and large-diameter valves. In order to reduce the operating torque of pneumatic ball valves and increase the reliability of sealing, oil sealed ball valves have emerged in recent years. They not only inject special lubricating oil between the sealing surfaces to form a layer of oil film, which enhances sealing performance but also reduces operating torque, making them more suitable for high-pressure large-diameter ball valves.
3. Elastic ball pneumatic ball valve
The ball of a pneumatic ball valve is elastic. Both the spherical and wide seat sealing are made of golden housing material, with a high sealing pressure ratio. The pressure of the medium itself cannot meet the sealing requirements, and external forces must be applied. This type of valve is suitable for
In high-temperature and high-pressure media
Elastic sphere is achieved by opening an elastic groove at the lower end of the inner wall of the sphere to obtain elasticity. When the channel is closed, the wedge head of the valve stem is used to expand the sphere and press it against the valve seat to achieve sealing. Before rotating the sphere, the wedge head is loosened to restore the original shape of the sphere, creating a small gap between the sphere and the valve seat, which can reduce friction and operating torque on the sealing surface.