Comparison of performance between floating ball and fixed ball valves

Ball valves, with their core advantages such as good sealing, low opening and closing resistance, smooth flow channels, and stable operation, have become the core equipment for pipeline interception, regulation, and flow control. Industrial ball valves are mainly divided into two categories based on the ball structure support method: floating ball valves and fixed ball valves. Accurately distinguishing the performance advantages and adaptation range of floating ball valves and fixed ball valves for the complex use scenarios of high-pressure industrial pipelines is the key to ensuring the safe, stable, and long-term operation of the entire fluid transportation system. This article will comprehensively compare the structural characteristics, core performance, advantages and disadvantages of two types of ball valves, with a focus on sorting out the key selection points for high-pressure pipeline special use, providing professional and practical selection references for valve procurement, working condition matching, and pipeline transformation in industrial projects.

1. Differences in structural principles: The support method determines the core performance

The core structural feature of the floating ball valve is that the ball has no fixed shaft support and is in a "floating" state as a whole, with the valve seat as the only support structure. When the pressure of the pipeline medium acts on the sphere, the sphere can slightly offset and squeeze towards the outlet valve seat, relying on the pressure of the medium to achieve automatic sealing. The structure is simple and compact, with few components and easy assembly and maintenance. Conventional small-diameter, medium low pressure ball valves mostly use floating ball structures, which have strong versatility.

The fixed ball valve adopts an upper and lower dual axis fixed support structure, and the ball is firmly fixed by the valve stem and lower shaft seat, without displacement during operation. During the opening and closing process, the sphere only rotates without displacement or compression, resulting in a stronger and more stable overall structure. At the same time, it is equipped with an independent valve seat spring pre tightening sealing structure, which can achieve good sealing without relying on medium pressure. It is specially designed for harsh working conditions such as large diameter, high pressure, and high frequency opening and closing.

2. Comparison of sealing performance

The sealing of floating ball valves relies on the self tightening of the medium pressure, and the sealing force is weak under low pressure. Slight pressure fluctuations are prone to micro leaks; When the pressure is sufficient, the sealing effect is good, achieving zero leakage and meeting the sealing requirements of conventional cleaning media, but not suitable for negative pressure and ultra-high pressure conditions.

The fixed ball valve comes with a pre tightened sealing structure, which is not affected by the pressure of the medium. It can maintain stable sealing under low pressure, high pressure, and negative pressure conditions. The metal hard sealed fixed ball valve can also adapt to high temperature, high pressure, and media containing trace impurities, with longer sealing life and better wear resistance.

3. Comparison of operation and wear resistance performance

The floating ball valve has a slightly movable ball body, and the friction area between the ball body and the valve seat is relatively large during opening and closing. Long term high-frequency opening and closing can easily cause valve seat wear, and the service life is relatively short. It is more suitable for low-frequency start stop and stable working conditions. And the opening and closing torque is small, both manual and electric drives can be easily adapted.

The fixed ball valve has no displacement of the ball body and minimal friction loss on the sealing surface during rotation, greatly improving wear resistance. It can meet the operational requirements of 24-hour continuous operation and high-frequency opening and closing of industrial production lines, with low failure rate and lower operation and maintenance costs. The only characteristic is that the opening and closing torque is relatively large, and large-diameter models require the pneumatic ball valve and motorized ball valve.

In summary, floating ball valves are mainly used for medium and low pressure, small diameter, and cost-effective conventional working conditions, and are the basic choice for general industrial pipelines; Fixed ball valves are mainly used for high-pressure, large-diameter, high-frequency start stop, and harsh industrial conditions, and are the core preferred valves for high-pressure pipelines in energy, petrochemical, and heavy industry.

KR VALVE (TIANJIN) Co., LTD

Email: info@tjkrvalve.com

Telephone: 0086 18920615838