1. Floating Ball Valves

The main feature of floating ball valves is that the ball has no supporting shaft and is supported by the valve seats at the inlet and outlet ends of the valve. The valve stem is flexibly connected to the ball. The ball of this type of valve is clamped between the two seats and remains in a "floating state". Driven by a handle or other actuation devices via the valve stem, the ball can rotate freely between the two seats.The main Ball valve product names of China Ball valve Network include:Ball valve product drawing，Air Supply Pipe Measurement Ball Valve，ALD4700 Straight Handle Forged Ball Valve(Articulated Type)，Forged Brass Ball Valve( Single Clamp Type)，Forged Brass Ball Valve (Double Clamp Type)，ANSI Fixed Three-section Ball Valve，ANSI/JIS Metal Hard-sealed Ball Valve，API Cast Steel Fixed Ball Valve，API Forged Steel Fixed Ball Valve.

When the flow hole of the ball is aligned with the valve channel hole, the ball valve is in the open state, allowing fluid to flow smoothly with minimal flow resistance. When the ball is rotated 90 degrees, its flow hole becomes perpendicular to the valve channel hole, and the valve is closed. Under the action of fluid pressure, the ball is pushed against the valve seat at the outlet end (referred to as the downstream seat) to achieve tight compression and reliable sealing.Ball Valve Products

Generally speaking, under the same other conditions, higher pressure facilitates better sealing. However, it is necessary to consider whether the seat material can withstand the load transmitted by the ball, as the force generated by fluid pressure on the ball is fully transferred to the downstream seat. In addition, for larger-sized floating ball valves, higher pressure leads to increased operating torque. Moreover, the ball itself has significant weight, resulting in uneven pressure distribution on the seat sealing surface—typically, the upper half along the horizontal plane of the channel diameter bears less pressure while the lower half bears more. This causes uneven seat wear and potential leakage. Therefore, floating ball valves are generally suitable for applications with ≤PN10 pressure class and ≤DN200 nominal diameter.

Currently, the ideal method for applying preload is to use ball valves with elastic seats. Elastic seats can greatly expand the range of elastic deformation of the seat itself, ensuring excellent sealing performance both at low and high pressures. As long as the operation is within the elastic deformation range of the seat, the sealing specific pressure can be basically maintained constant, preventing seat damage due to overload. Examples of elastic seat structures are as follows:

2. Trunnion-mounted Ball Valves

In trunnion-mounted ball valves, the ball is integrated with the upper and lower valve stems (or manufactured as an integral shaft-connected ball, where the ball is forged or welded with the upper and lower stems and mounted on bearings). The ball can rotate freely around the axis perpendicular to the valve channel but cannot move along the channel axis.

Therefore, during the operation of trunnion-mounted ball valves, the force generated by upstream fluid pressure on the ball is fully transmitted to the bearings, without causing the ball to shift toward the downstream seat. This prevents excessive pressure on the seat, resulting in small operating torque, minimal seat deformation, stable sealing performance, and long service life. Such valves are suitable for high-pressure and large-diameter applications.

The key to the sealing performance of trunnion-mounted ball valves lies in the correct selection of the elastic seat structure, reasonable design of seat dimensions, and ingenious utilization of fluid pressure or spring force to meet sealing requirements.

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