As a kind of pipeline pressure element for industrial automation process control, electric ball valve is usually used for remote on and off control (connecting and cutting off medium) of pipeline medium. It is characterized by its integrated structure, which permits its operation could be controlled with single-phase power supply AC220V and DC power supply 24VDC. It possess advantages of savings in space, weight, reliable performance, simple fittings, large flow capacity and so on.
I. Structure and Characteristics of Electric Ball Valve
The electric ball valve has a simple structure and is only composed of a few parts, saving data consumption with small volume, light weight, small installation size, low driving torque, pressure regulating valve, simple and agile operation. It will be quick to operate when the valve is turned 90 degrees; Besides, it also has good flow regulation effect and sealing characteristics. Electric ball valve has taken the lead position in large and medium diameter and medium and low pressure applications.
When the electric ball valve is in a fully opened position, the butterfly plate thickness is the only influence factor to resistance when the medium flows through the valve body, hence, the valve has a relatively low pressure drop, allowing stable flow control.
The electric ball valve has two sealing types: elastic seal and metal seal.
For the elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate. The service life of the valve with metal seal is generally longer than that of the valve with elastic seal, but it is difficult to achieve complete seal.
Metal seal can adapt to higher working temperature, while elastic seal is limited by temperature.
The selection of the valve size and type is of importance if the electric ball valve is required to be used for flow control. The construction principle of the electric ball valve is well suited for manufacturing large-diameter valves. Electric ball valves are not only widely used in general industries such as petroleum, gas, chemical industry and water disposal, but also used in the cooling water system of thermal power plants.
II. Classification of Electric Ball Valve
There are two kinds of commonly used electric ball valves: wafer electric ball valve and flange electric ball valve.
The wafer type electric ball valve employs the stud bolts to connect the valve between two pipe flanges. The flange type electric ball valve has flanges on the valve itself, and the flanges at both ends of the valve are connected to the pipe flanges with bolts.
The strength property of the valve is referred to as the ability to withstand medium pressure. Valve, as a mechanical product against internal pressure, must have sufficient strength and stiffness to ensure long-term use without rupture or deformation.
