The structure of the electric ball valve is simple, consisting of only a few parts, and the material consumption is low; the structure of the electric ball valve is small in size, light in weight, and small in installation size, and the driving torque is small, and it is easy with agile operation, which just needs to rotate 90° to open and close quickly.
At the same time, it also has good flow regulation function and closed sealing characteristics. In the application field of large and medium caliber, medium and low pressure, electric ball valve is the dominant valve form.
When the electric ball valve is in the fully open position, the thickness of the disc is the resistance when the medium flows through the valve body, so the pressure drop through the valve is very small, so it has better flow control characteristics.
Electric ball valves have two types of seals: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be inlaid on the valve body or attached to the periphery of the disc. Electric ball valves with metal seals generally have a longer life than those with elastic seals, but it is difficult to achieve complete sealing.
Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being limited by temperature. If an electric ball valve is required to be used as a flow control, it is important to choose the correct size and type of valve.
The construction principle of the electric ball valve is especially suitable for the manufacture of large-diameter valves. Electric ball valves are not only widely used in general industries such as petroleum, gas, chemical, and water treatment, but also in the cooling water system of thermal power plants.
Commonly used electric ball valves include two types: wafer type electric ball valve and flange type electric ball valve. Wafer type electric ball valve is to connect the valve between two pipeline flanges with stud bolts. Flange type electric ball valve has flanges on the valve, and bolts are used to connect the flanges at both ends of the valve to the pipe flanges.
The strength performance of the valve refers to the ability of the valve to withstand the pressure of the medium. The valve is a mechanical product subject to internal pressure, so it must have sufficient strength and rigidity to ensure long-term use without cracking or deformation.
Ball valves are divided into: floating ball valve, fixed ball valve, orbital ball valve, v-shaped ball valve, three-way ball valve, stainless steel ball valve, forged steel ball valve, ash discharge ball valve, anti-sulfur ball valve, three-way ball valve, pneumatic ball valve, electric ball valve, ferrule Ball valve, welded ball valve.
1. Floating ball valve
The ball of the ball valve is floating. Under the action of the medium pressure, the ball can produce a certain displacement and press tightly on the sealing surface of the outlet end to ensure the sealing of the outlet end.
The floating ball valve has a simple structure and good sealing performance, but the load of the ball bearing the working medium is all transferred to the outlet sealing ring. Therefore, it is necessary to consider whether the sealing ring material can withstand the working load of the ball medium. Sphere may deflect when subjected to higher pressure shocks. This structure is generally used for medium and low pressure electric ball valves.
2. Fixed ball valve
The ball of the ball valve is fixed and does not move under pressure. The fixed ball valve has a floating valve seat. After being pressurized by the medium, the valve seat moves, so that the sealing ring is tightly pressed on the ball to ensure the sealing.
Bearings are usually installed on the upper and lower shafts of the ball, and the operating torque is small, which is suitable for high pressure and large-diameter electric ball valves.
3. Elastic ball valve (ie orbital ball valve)
The ball of the elastic electric ball valve is elastic. Both the ball and the valve seat sealing ring are made of metal materials, and the sealing specific pressure is very large. The pressure of the medium itself cannot meet the sealing requirements, and external force must be applied. This valve is suitable for high temperature and high pressure medium.
The elastic sphere is obtained by opening an elastic groove at the lower end of the inner wall of the sphere to obtain elasticity. When closing the channel, use the wedge head of the valve stem to expand the ball and press the valve seat to achieve sealing.
Before turning the ball, loosen the wedge head, and the ball will return to its original shape, so that there is a small gap between the ball and the seat of the elastic electric ball valve, which can reduce the friction and operating torque of the sealing surface.