The main differences between trunnion and floating ball valves
Feb 12, 2019
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Ball valves can be classified by material, structure, flow port, working principle and so on. As per the working principle and structure, we can divide ball valves into floating type and trunnion-mounted type. In this article, we will discuss the main differences between these two types.
Under the pressure of the medium, the ball of floating type moves against downstream sealing. When the trunnion-mounted type works, the ball remains fixed. The trunnion ball valve is composed of an upper stem and a fixed shaft at the bottom, while the floating type is with an upper stem only. The floating type is widely used in small size and low pressure condition. On the contrary, the trunnion ball valves are often used in large size and high pressure condition.
The three aspects mentioned above are the main differences between them. Certainly, there are other perspectives. The trunnion-mounted type has the double block and bleed function (DBB), and its seat is more reliable with a metal seat support.