One piece ball valve and flange gate valve belong to the same type of valve, the difference is that its closing part is a ball, and the ball rotates around the center line of the valve body to open and close a valve. Ball valve is mainly used to cut off, distribute and change the flow direction of medium in pipeline. Wide ball valve is a new type of valve widely used

Internal thread two-piece ball valve and gate valve belong to the same type of valve, the difference is that its closing part is a ball, and the ball rotates around the center line of the valve body to open and close a valve. Ball valve is mainly used to cut off, distribute and change the flow direction of medium in pipeline

Three piece ball valve and gate valve belong to the same type of valve. The difference is that the closing part is a ball, and the ball rotates around the center line of the valve body to open and close the valve. Three piece ball valve is mainly used to cut off, distribute and change the flow direction of medium in pipeline

Cast steel ball valve came out in the 1950s. With the rapid development of science and technology, the continuous improvement of production technology and product structure, it has rapidly developed into a major valve category in a short period of 40 years. In the developed countries of western industry, the use of ball valve is increasing year by year. In China, ball valve is widely used in petroleum refining, long-distance pipeline, chemical industry, papermaking, pharmaceutical industry, water conservancy, electric power, municipal administration, steel and other industries, and plays an important role in the national economy.

The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of butterfly valve body, the disc type butterfly plate rotates around the axis with the rotation angle between 0 ° - 90 °. When it rotates to 90 °, the valve will be fully open.

Swing check valve, also known as one-way valve or check valve, is used to prevent backflow of medium in the pipeline. The opening and closing parts automatically open or close by the medium flow and force, so as to prevent the backflow of medium. The valve is called check valve. The check valve belongs to the automatic valve category, which is mainly used on the pipeline with one-way flow of medium. It only allows the medium to flow in one direction to prevent accidents. This type of valve shall be installed horizontally in the pipeline [1].

Unlike parallel gate valves, wedge gate valves also have single wedge valves. The two sealing surfaces of the most commonly used wedge gate valve form a wedge, and the wedge angle varies with the valve parameters, usually 50. The ram of wedge gate valve can be made into a whole, which is called rigid ram; it can also be made into a ram that can produce slight deformation, so as to improve its processability and make up for the deviation of sealing surface angle in the process of processing. This kind of ram is called elastic ram.

1. The fluid resistance is small, and its resistance coefficient is equal to that of the same length of pipe section. 2. Simple structure, small volume and light weight. 3. It is tight and reliable. At present, the sealing surface material of gate valve is widely used in plastic, with good sealing performance, and also widely used in vacuum system. 4. It is easy to operate and fast to open and close. It only needs to rotate 90 ° from full open to full close, which is convenient for remote control. 5. The maintenance is convenient, the gate valve structure is simple, the sealing ring is generally movable, and the disassembly and replacement are relatively convenient. 6. When the valve is fully open or closed, the sealing surface of the ball and the valve seat shall be isolated from the medium. When the medium passes through, the corrosion of the valve sealing surface will not be caused. 7. It has a wide range of applications, ranging from small diameter to several millimeters and large diameter to several meters, from high vacuum to high pressure.