1. Floating Ball & Fixed Ball Type
In this design, only the upper surface of the ball is supported by the stem, while the ball itself is pressed and sealed by pre-load and medium pressure. The outlet end of the valve and the ball bear all the pressure, giving the sealing surface high strength.
For the fixed-ball design, the ball is secured at both the top and bottom by the stem, creating a rigid connection. This structure features low operating torque and is suitable for high-pressure, large-diameter valves. However, the structure is more complex and adopts a floating seat design.
2. Side-Entry Ball Valve
The ball and internal components are inserted into the valve body from the side.
One-piece side-entry valves are compact and lightweight, typically used for small-diameter cast-steel valves with non-metallic seats.
Two-piece side-entry valves are easier to manufacture and available in many variations, making them the most common type. The valve body is made of two sections connected by bolts and nuts, resulting in a slightly longer structure.
3. Top-Entry Ball Valve
Internal components are assembled from the top. Usually produced via casting, this design has good structural rigidity and is suitable for medium- and large-diameter valves across a wide range of pressure classes.
A key advantage is that maintenance can be performed without removing the valve from the pipeline—internal parts can be replaced in-line.
However, the valve cavity is larger, and the overall structure is longer and heavier.
4. Fully-Welded Ball Valve
The valve body is formed by fully welding plates or pipe components. The internal mechanism is similar to that of a three-piece ball valve.
With no external leakage points and high resistance to pipeline stress, this type is ideal for long-distance pipelines, especially underground or in harsh oil and gas environments.
Since internal parts are sealed and not exposed to the atmosphere, service life is long.
However, internal components cannot be replaced or repaired, and the cost is relatively high.