Sealing Principle And Structural Characteristics Of Lined Ball Valve

Publish Time: 09/13 2025 Author: Site Editor Visit: 1

Lined Ball Valve are the most commonly purchased ball valve product on industrial product procurement websites and are one of the most popular ball valves.
1. Sealing Principle of Trommeled Ball Valves
The opening and closing mechanism of a trommeled ball valve consists of a sphere with two supporting shafts. A central channel is equal to the pipe diameter, and two floating valve seats are located on either side. The ball rotates without deviating from the axis of the supporting shafts, which are supported by upper and lower sliding bearings. The valve seats are floating, and the force of the medium pushes against the ball, generating contact stress to ensure a reliable seal. Like a floating ball valve, the valve rotates 90° from open to closed, or vice versa.
2. Structural Features of Trommeled Ball Valves
① The combined dimensions of the ball and seat are free-standing, unlike floating ball valves, which form a sealing dimension chain. Therefore, their sealing performance is structurally unaffected by temperature and pressure fluctuations.

② While the media's self-sealing principle is also employed, the media force in a trunnion-mounted ball valve acts on the annular area of the valve seat. This is significantly less than in a floating ball valve, where the media force acts on the entire channel interface. Furthermore, this force can be controlled through proper design. Therefore, this structure is suitable for ball valves up to NPS 60 and pressure ratings up to class 2500, making it a key structural form in ball valve development.
③ For the same reasons mentioned above, the operating torque of a ball valve is also significantly lower than that of a floating ball valve.
④ Its structure is more complex than a floating ball valve, resulting in greater weight and a higher price than a floating ball valve of the same specification.
⑤ It can be designed in full-bore, standard-bore, and reduced-bore configurations, offering greater flow capacity and a lower flow resistance coefficient.