Ball valve concept and industry classification analysis

The ball valve is mainly composed of a valve body, a valve stem, a ball body and a seal ring, and is a 90° switch shut-off valve. It applies a certain torque on the upper end of the valve stem by means of a handle or a drive device and transmits it to the ball body, making it rotate by 90°. The through hole of the ball coincides with the center line of the valve body passage or is vertical, and completes the full opening or full closing action. The commonly used ball valve structure is divided into two categories: floating ball ball valve and fixed ball ball valve.

The ball of the floating ball valve is freely supported on the sealing ring, and under the action of the fluid pressure, it is in close contact with the downstream sealing ring to form a downstream single-side seal. It is suitable for low pressure, small diameter applications.

The ball of the fixed ball valve has upper and lower rotation shafts and is fixed in the bearing of the ball. Therefore, the ball is fixed, but the sealing ring is floating, and the sealing ring is pressed against the ball by the spring and the fluid thrust to generate the upstream seal. Suitable for high pressure, large diameter occasions.

Direct welded ball valves are suitable for use in underground facilities, offshore work platforms and subsea equipment. The straight welded ball valve adopts high quality forged parts and is integrated in the middle part of the valve through a single layer of welding to make the shape of the valve more similar to a spherical shape. The structure of the valve is more compact, lighter in weight, and stronger in strength. Single-layer straight welding also enables the manufacture of high-precision valves, allowing full sealing between the seat and ball. The completely welded and unbolted valve body design completely eliminates external leakage. At the same time, the ball valve adopts a fireproof structure design without any maintenance.

Track ball valve is a kind of multi-rotary ball valve. It adopts the principle of tilting and rotating to eliminate scratches on the sealing surface. When the valve is closed, the core is pressed against the sealing seat by the mechanical force, and the tight seal can be ensured without relying on the pressure differential; when the valve is opened, the ball tilts away from the valve seat and the fluid flows along the ball. 360o evenly through the valve surface of the core, can eliminate the high-speed fluid local erosion erosion of the valve seat. Since the valve does not have friction when it is opened or closed, the operation is light and reliable.