The structure principle of electric ball valve
The electric ball valve has a simple structure, consisting of only a few parts, and saves data consumption; small size, light weight, small installation size, electric ball valve structure diagram, small driving torque, pressure regulating valve, simple and agile operation, only need to rotate 90° It can be opened and closed quickly; and it also has good flow regulation efficiency and sealing characteristics at the same time. In the application of large and medium caliber, medium and low pressure, electric ball valve is the dominant valve form.
When the electric ball valve is in a fully open position, the thickness of the butterfly plate is the resistance when the medium flows through the valve body, so the pressure drop that occurs through the valve is very small, so it has better flow control characteristics. The electric ball valve has two sealing types: 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 butterfly plate. Valves with metal seals generally have a longer life than valves with elastic seals, but it is difficult to achieve a complete seal.
Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being limited by temperature. If the electric ball valve is requested to be used as a flow control, it is important to accurately select the size and type of the valve. The construction principle of the electric ball valve is particularly suitable for manufacturing large-diameter valves. Electric ball valves are not only widely used in general industries such as petroleum, gas, chemical, and water disposal, but also used in cooling water systems of thermal power stations.
Commonly used electric ball valves include wafer type electric ball valves and flange type electric ball valves. Wafer type electric ball valve uses double-head bolts to connect the valve between two pipeline flanges. Flange type electric ball valve is equipped with flanges on the valve, and the two flanges of the valve are connected to the pipeline flange with bolts. 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.
The classification of electric ball valve
ball valves are divided into: floating ball valve, fixed ball ball valve, orbital ball valve, v-shaped ball valve, three-way ball valve, stainless steel ball valve, forged steel ball valve, ash unloading ball valve, sulfur-resistant ball valve, three-way ball valve, pneumatic ball valve, electric ball valve, card sleeve ball valves, welded ball valves. 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 that the outlet end is sealed.
The floating ball valve has a simple structure and good sealing performance, but the load of the working medium on the sphere is all transmitted to the outlet sealing ring. Therefore, it is necessary to consider whether the material of the sealing ring can withstand the working load of the sphere medium. When subjected to a higher pressure impact , The sphere may shift. This structure is generally used for medium and low pressure ball valves. Fixed ball valve
The ball of the ball valve is fixed and does not move when pressed. The fixed ball valve is equipped with a floating valve seat. After the pressure of the medium, the valve seat moves, so that the sealing ring is pressed tightly on the ball to ensure sealing. Bearings are usually installed on the upper and lower shafts of the sphere, and the operating torque is small, which is suitable for high-pressure and large-diameter valves. In order to reduce the operating torque of the ball valve and increase the reliability of the seal, oil-sealed ball valves have appeared in recent years. Special lubricants are injected between the sealing surfaces to form an oil film, which enhances the sealing performance and reduces the operating torque. , It is more suitable for high-pressure and large-caliber ball valves. Resilient ball valve (or track ball valve)
The ball of the 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 media.
Elastic sphere is to open an elastic groove on the lower end of the inner wall of the sphere to obtain elasticity. When closing the passage, use the wedge-shaped head of the valve stem to expand the ball and press the valve seat to seal. Loosen the wedge-shaped head before rotating the sphere, and the sphere will return to its original shape, so that there is a small gap between the sphere and the valve seat, which can reduce the friction of the sealing surface and the operating torque.