What Is the Difference Between Floating and Trunnion Ball Valves?

Fundamental differences between floating ball valves and fixed shaft ball valves

For professionals in the valve industry, the difference between floating ball valves and fixed shaft ball valves is a basic but critical knowledge point. There are significant differences between these two valves in terms of structure, working principle, performance and application fields. This article will conduct an in-depth analysis and discussion of these differences in order to help readers better understand and master the characteristics and applications of these two valves.

1. Differences in valve structure

The ball of the floating ball valve is floating and is not fixed in the valve body. Its position is maintained mainly through the medium pressure and spring preload. When the valve is closed, the ball is pressed against the valve seat by the pressure of the medium, thereby achieving sealing, ball valve manufacture.

In contrast, the ball of a fixed-axis ball valve is fixed in the valve body through a fixed axis, and the ball can rotate around this axis. This structure allows the fixed-axis ball valve to maintain a stable position regardless of whether it is open or closed, and will not be affected by the medium pressure.

2. Differences in working principles

The working principle of floating ball valve is relatively simple. When the valve opens, the medium pressure pushes the ball away from the valve seat, leaving the valve in an open state. When the valve is closed, the medium pressure pushes the ball back to the valve seat to achieve a seal. In this process, the spring preload acts as an auxiliary seal, wholesale gate valve.

The working principle of fixed shaft ball valve is more complicated. When the valve is opened, the actuator (such as an electric actuator or pneumatic actuator) needs to be used to drive the ball to rotate 90 degrees to keep the valve in the open state. When closing the valve, it is also necessary to drive the ball back to its original position through the actuator to achieve sealing. During this process, the presence of a fixed axis allows the ball to rotate stably, enabling precise opening and closing.

Video Link Address: https://www.youtube.com/watch?v=PnafJX-e2KI

3. Differences in performance

Due to structural differences, floating ball valves and fixed-axis ball valves also differ in performance. The sealing performance of the floating ball valve mainly depends on the contact pressure between the ball and the valve seat and the size of the spring preload. Therefore, this kind of valve may have leakage problems in high pressure differential or high temperature environments. In addition, the anti-scouring ability of floating ball valves is relatively weak and is easily affected by media erosion, resulting in a decrease in sealing performance.

In contrast, the sealing performance of fixed shaft ball valves is more reliable. Since the ball is fixed in the valve body through a fixed shaft, the ball can maintain a stable position no matter how the medium pressure changes, thereby achieving reliable sealing. In addition, fixed shaft ball valves also have strong erosion resistance and can maintain good performance in harsh working environments, forged ball valve.

4. Differences in application fields

Due to differences in performance and structure, floating ball valves and fixed-axis ball valves also have different application fields. Floating ball valves are mainly used in low-pressure, low-temperature, small-diameter pipeline systems, such as household water pipes, heating pipes, etc. These occasions have relatively low requirements on the sealing performance and erosion resistance of the valve, so the floating ball valve can meet the requirements.

Fixed-axis ball valves are widely used in high-pressure, high-temperature, large-diameter pipeline systems such as petroleum, chemical industry, and natural gas. These occasions have high requirements on the sealing performance, erosion resistance, stability and safety of the valve, so fixed shaft ball valves are more suitable, api 6d ball valve.

5. Comparative analysis data table

In order to more intuitively demonstrate the differences between floating ball valves and fixed shaft ball valves, we have created a comparative analysis data table:

Items Floating ball valve Fixed shaft ball valve
Structural features: The ball floats, and its position is maintained by the medium pressure and spring preload. The ball is fixed in the valve body through a fixed axis and can rotate around the fixed axis.Working principle: When opening, the medium pressure pushes the ball open; when closing, the medium pressure pushes the ball back to achieve sealing. The actuator drives the ball to rotate 90 degrees to achieve opening and closing.
Sealing performance: Affected by the contact pressure between the ball and the valve seat and the spring preload, leakage may occur in high pressure differential or high temperature environments. Not affected by medium pressure, the sealing performance is reliable Anti-erosion ability Relatively weak, easily affected by media erosion, resulting in reduced sealing performance Stronger, capable of maintaining good performance in harsh working environments
Application areas Low pressure, low temperature, small diameter piping systems High pressure, high temperature, large diameter piping systems

The above content analyzes the differences between floating ball valves and fixed shaft ball valves in terms of structure, working principle, performance and application fields. By comparing and analyzing the data tables, the respective characteristics and advantages of these two valves can be clearly seen. I hope this article can help readers better understand and master the characteristics and applications of these two valves and provide valuable reference information for professionals in the valve industry.