It can be divided into top-mounted type (top-mounted type), side-mounted type, oblique-mounted type, etc. For side-mounted ball valves, according to the different applications and the size of the diameter, the valve body has two types: integral type and split type. The split type is divided into two parts (two-piece type) and three-piece type (three-piece type).
1. Top-mounted ball valve
The structural feature of the top-mounted ball valve is that the valve body is made as a whole, the upper part of which is provided with a valve cover, and the ball, sealing ring, and valve seat are all installed from the upper part of the valve body. The advantages of the top-mounted ball valve: when repairing or replacing the valve seat, it is not necessary to remove the ball valve from the pipeline, just open the valve cover and lift the ball out. This brings great convenience to the underground pipeline, especially the ball valve used in the atomic energy industry. . For three-way, four-way and multi-way ball valves, it is inconvenient to load or take out from any end of the channel due to the large ball body. In addition, the cavity of the valve body of the multi-way ball valve itself is very large. More superior.
The disadvantage of the top-mounted ball valve is that the valve body is large in size and heavy, so it is generally not used in high-pressure occasions.
2. Side mounted ball valve
(1) Side-mounted integral ball valve
The ball is inserted from one end of the valve body, and the valve seat and the ball are fixed and pressed tightly with a screw sleeve. This kind of ball valve has a simple structure, a small number of parts, and is easy to manufacture and install. It is suitable for occasions with small diameters, especially for viscous or easy-to-crystallize media, such as urea, where the valve body needs to be made into an insulation jacket. It adopts a side-mounted integral structure.
Figure 9-6 Side-mounted integral ball valve
(2) Side-mounted two-piece ball valve (two-piece ball valve)
A ball valve in which the valve body is divided into two asymmetric left and right halves along the vertical section of the channel axis, the sphere is inserted from the sectioned hole, and the left and right halves are flanged or threaded.
Since the valve body is divided into two halves, compared with the integral type, the single-piece weight of the half valve body is lighter, and the casting (forging) and mechanical processing are convenient. This kind of ball valve is suitable for promotion.
(3) Side-mounted three-piece ball valve (three-piece ball valve)
For ball valves with larger nominal sizes, in order to facilitate manufacturing and assembly, the side-mounted three-part structure is often used, that is, the valve body is divided into three parts along the cross-section perpendicular to the axis of the channel at the two seat parts, and the whole valve is along the valve The center axis of the rod is symmetrical, with smooth lines, beautiful appearance and convenient manufacturing, which is suitable for manufacturing large valves with small equipment. The disadvantage of this structure is that a pair of large flanges is added, and the total weight of the valve body is increased.