Performance and Design Optimization of Pneumatic Orbital Ball Valves in Harsh Marine Conditions

5. Design of Pneumatic Track Ball Valves

5.1 Structure and Materials

In the design of pneumatic track ball valves, structural optimization and material selection are critical to ensuring stability and reliability in extreme marine environments. The structural design focuses on the connection between the valve body and valve seat, utilizing advanced finite element analysis (FEA) to identify stress concentration areas. This ensures the ball valve can withstand high pressure and strong vibrations, as shown in Figure 2. Featuring a floating design, the valve seat allows the ball to self-align under fluid pressure, improving contact at the sealing interface and minimizing the risk of leakage.

Additionally, to enhance corrosion resistance, the valve’s outer surface is coated in strict accordance with Q/BZH 11107.06-2021 and Q/BZH 11207.06-2021—China’s general technical specifications for actuated ball valves used in offshore oil and gas fields. The coating is inspected item by item according to key inspection criteria to ensure resistance to chloride ion corrosion from seawater, as well as other chemical agents (Figure 3) . The pneumatic actuator is protected by a three-layer coating, with a total thickness of up to 280 μm, applied to the shell surface. This effectively shields the internal mechanical components from moisture and salt in the marine atmosphere. Meanwhile, the use of low-temperature-resistant internal components ensures reliable switching performance even under extremely cold conditions. Sealing materials are carefully selected for their ability to retain elasticity at low temperatures, ensuring uninterrupted power transmission.

In summary, this section introduces a set of scientifically grounded and innovative design strategies aimed at improving the reliability and efficiency of pneumatic track ball valves in marine engineering. The proposed design not only overcomes the limitations of traditional valve technologies but also makes a significant contribution to the safety and environmental sustainability of offshore operations.

5.2 Performance Analysis

The study provided an in-depth analysis of the pneumatic track ball valve’s fluid dynamics, quantitatively evaluating its flow coefficient. The flow coefficient C, a key parameter, indicates the valve’s flow capacity under a unit pressure drop and is crucial for ensuring the stable operation of the track ball valve in marine engineering applications. Based on this, formula (1) describes the relationship between the pressure difference ΔP across the valve and the flow coefficient C at a specific flow rate Q.

Where:

G_f is fluid density, kg/m³

G is gravitational acceleration, m/s²

This flow performance analysis method provides a theoretical foundation for accurately predicting valve behavior under the complex and variable conditions of the marine environment. In summary, the performance analysis of pneumatic track ball valves involves not only the precise measurement of parameters such as the flow coefficient, but also a thorough investigation of the valve’s dynamic characteristics and a rigorous evaluation of its structural strength. The effective integration of these aspects provides a solid theoretical foundation and technical assurance for the application of track ball valves in marine engineering. Future work will focus on further optimizing valve design to enhance reliability and cost-effectiveness in harsh marine environments.

Table: Key Points for Final Inspection of Coating

Figure 2 Static stress analysis of the orbital ball valve bodies

6. Case Study Analysis

6.1 Engineering Case Study

In a project conducted by an offshore engineering company in Huizhou, a natural gas molecular sieve unit was implemented, offering an opportunity to integrate theoretical analysis with practical application. Based on finite element analysis (FEA) theory, a detailed numerical model of the ball valve was developed to simulate its fluid flow characteristics and structural stress distribution under actual operating conditions.

Using SOLIDWORKS software, an in-depth flow field simulation was conducted to accurately calculate the internal flow velocity, pressure distribution, and vortex intensity of the orbital ball valve, thereby ensuring the accuracy and scientific validity of the predictions. Simultaneously, SOLIDWORKS was used to evaluate the structural strength and fatigue life of the valve. Figure 4 shows a stress cloud diagram of the valve body under 1.5 times the design pressure. The maximum stress observed in the structure was 20.65 MPa, while the minimum was 2.697 × 10⁻¹ MPa—both well below the compressive strength of the valve material—demonstrating that the valve body meets the requirements for both design and operational conditions. A comprehensive analysis of the pneumatic actuator’s static and dynamic performance was conducted, including testing and optimizing key parameters such as valve opening and closing times, torque values, and torque curves. Additionally, the actuator model was integrated with the control system using MATLAB and Simulink. An improved control strategy based on PID theory was proposed to enhance response speed and positioning accuracy. Virtual prototype testing was conducted using SOLIDWORKS and ADAMS software to simulate and analyze the dynamic behavior of the ball valve during repeated opening and closing cycles. This simulation facilitated the identification and evaluation of wear patterns in critical components. Extensive operational data from the pneumatic track ball valve installed on the offshore platform were collected and analyzed using data mining techniques. A deep learning-based fault prediction model was developed to effectively identify potential operational risks and enable proactive maintenance, thereby ensuring the safe and efficient operation of the valve system. The research findings demonstrate that thorough analysis and targeted improvements to the overall performance of pneumatic track ball valves can significantly enhance their durability and operational reliability in harsh marine environments. This provides strong support for fluid control in marine engineering. Moreover, the simulation methods and improvement strategies presented in this study offer valuable reference and practical guidance for the design and optimization of similar valves.

6.2 Performance Evaluation and Optimization

In the marine engineering application of pneumatic track ball valves, evaluating and optimizing their operational performance is a critical process. A comprehensive analysis of valve performance involves not only technical parameters and operating data, but also the integration of real-world marine environmental factors to assess reliability and durability under complex and variable conditions.

This study adopts a combined approach of simulation and field testing. First, a finite element model of the ball valve is developed using CAE (Computer-Aided Engineering) software (see Figure 5) to simulate stress and strain distribution under various operating conditions (see Figure 4). Subsequently, a laboratory test bench simulating a marine environment is established, where the valve undergoes repeated actuation cycles. Key performance parameters—such as leakage rate, actuation time, and actuator gas consumption—are recorded. For data analysis, multivariate regression is employed to explore the relationship between marine environmental factors (e.g., temperature, pressure, salt spray) and valve performance metrics. This helps identify which environmental variables significantly impact the valve’s service life and reliability. Additionally, to further evaluate the valve’s corrosion and pressure resistance, it is exposed to a simulated seawater environment and monitored continuously. After 168 hours, physical and chemical test results are presented in Tables 1 through 4, analyzing changes in chemical composition, mechanical properties, and the microstructure of internal components.

Figure 4: Static strain analysis of the orbital ball valve body

Figure 5: The 3D assembly model

Materials and Test Results

Table 1 presents the chemical analysis of the pneumatic track ball valve stem (material: 17-4PH). The content of all major elements falls within the standard range, confirming compliance.

Table 2 shows that the stem's main mechanical properties exceed the standard requirements, and the results are qualified.

Table 3 provides the chemical composition data for the ball and valve seat (material: F316), indicating that all values are within the standard range, meeting the required specifications.

Table 4 displays the mechanical property results of the ball and valve seat, which also exceed standard values and are deemed qualified.

Table 1. Chemical Composition Analysis of Valve Stem (17-4PH)

Table 2. Mechanical Property Test of Valve Stem

Note: The hardness was measured at three different positions (34.5, 35.0, and 35.0), and the average value was taken.

Table 3. Chemical Composition Analysis of Ball and Seat (F316)

Table 4. Mechanical Property Test of Ball and Seat (F316)

In summary, this study provides a detailed analysis of the operational status and physical-chemical conditions of pneumatic track ball valves in marine engineering. Through scientifically rigorous experimental design and efficient, accurate data processing, it offers a solid theoretical and practical foundation for optimizing valve design and improving performance.

7. Conclusion

The application of pneumatic track ball valves in marine engineering has demonstrated significant advantages. With precise fluid control and reliable sealing, these valves enable efficient operation in harsh marine environments. Their structural design, based on fluid dynamics principles, provides excellent flow resistance characteristics. The valve trim components are fabricated from corrosion-resistant materials such as 316 stainless steel and STL, with welded sealing surfaces that meet the stringent demands of marine environments and significantly extend the valve’s service life. In the pneumatic control system, high-response pneumatic actuators are employed to ensure stability and precision during rapid switching operations. The flow control unit can achieve a maximum flow rate of 300 L/min when the gas supply pressure is maintained between 0.4 and 0.6 MPa, thereby sustaining reliable switching performance even under high flow conditions. In practical marine engineering applications, pneumatic track ball valves have demonstrated robust performance in systems such as molecular sieves and marine oil and gas transportation. For example, during the development of a specific offshore oil field, the use of these valves effectively reduced operational costs and manpower requirements. Moreover, testing under extremely low temperatures and high-salinity conditions has demonstrated that these valves outperform similar products on the market, exhibiting significantly enhanced corrosion resistance and anti-icing capabilities—making them ideally suited for offshore platform environments.

In conclusion, pneumatic track ball valves not only enable efficient and reliable fluid control in marine engineering but also offer effective solutions to technical challenges in complex marine environments. Through scientific design, rigorous material selection, and advanced control systems, these valves clearly demonstrate their critical role and significance in this field.