Comparing V-Port Ball Valves and Single-Seat Control Valves

As vital components in fluid control, V-port ball valves and single-seat control valves play crucial roles in their respective applications. V-port ball valves are increasingly favored for their excellent regulation performance and zero leakage characteristics, while single-seat control valves are widely used due to their simple structure and reliability. This article will explore the structural features, performance advantages, and suitable scenarios for these two types of valves, providing users with comprehensive guidance for selecting appropriate fluid control elements.

Overview of V-Port Ball Valves

V-port ball valves are innovative control valves featuring a spherical valve core with a V-shaped opening on one side. By adjusting the valve core's opening, the flow area of the medium can be effectively controlled, allowing for precise flow regulation. Key structural features include:

1. Low Fluid Resistance

The design of V-port ball valves results in lower fluid resistance and a higher flow coefficient, typically achieving an adjustable range of 100:1, significantly higher than the traditional straight-through single-seat control valve (30:1). This makes V-port ball valves ideal for applications requiring large flow rates and high adjustment precision.

2. Reliable Sealing

When using a hard seal structure, the sealing surface of the valve core can be treated with techniques such as hard chrome plating, cobalt-based hard alloy overlay, or tungsten carbide spraying. These treatments greatly enhance the sealing lifespan of the valve core. The design allows for zero leakage, making it suitable for applications with strict leakage requirements.

3. Efficient Rotary Stroke

The valve core of a V-port ball valve requires only a 90° turn from fully open to fully closed. When paired with a pneumatic actuator, it can quickly cut off the flow of the medium. Installing an electric valve positioner allows for precise proportional adjustments based on a 4-20 mA analog signal.

4. Automatic Wear Compensation

The fixed ball structure and spring-loaded valve seat of the V-port ball valve can move along the flow path, effectively compensating for wear on the valve core and extending its lifespan. Depending on actual needs, springs can be selected in various forms, including hexagonal springs, wave springs, disc springs, or cylindrical compression springs.

5. Contamination Protection Design

When dealing with media containing fine impurities, a sealing ring needs to be added to the spring to prevent impurities from entering, ensuring the valve operates normally and has a long lifespan.

Overview of Single-Seat Control Valves

Single-seat control valves are the most common type of control valve, characterized by their simple yet effective structure. They consist of a valve core and a valve seat, with key structural features including:

1. Structural Features

The upper cover plate compresses the packing to ensure sealing. The upper valve cover is bolted to the valve body, positioning the valve stem and valve core. The valve seat connects to the upper valve cover, ensuring precise alignment of the valve core and seat.

2. Flow Regulation Function

The movement of the valve core alters the flow area of the fluid, allowing for precise control of fluid flow. The valve stem is fixed to the valve core using a connecting pin, and guiding methods can be top-guided or top-and-bottom guided to improve guiding accuracy.

3. Leakage and Pressure Differential

Single-seat control valves have low leakage rates, with standard leakage reaching 0.01% C.C. The permissible pressure differential for a DN100 valve is only 120 kPa, and the flow coefficient is relatively small (around 100). Due to the significant thrust from the fluid medium on the valve core, these valves are not suitable for high pressure differential and large diameter applications.

4. Guiding Design

Some small flow spherical control valves utilize seat guiding methods to ensure the stability of the valve core. For single-guided straight-through single-seat valves with a diameter of less than 25mm, they usually can only achieve positive body valves.

Comparison of V-Port Ball Valves and Single-Seat Control Valves

In fluid control applications, both V-port ball valves and single-seat control valves have unique advantages and suitable scenarios. Here is a detailed comparison of the two.

1. Size and Weight

V-port ball valves are smaller and lighter than single-seat control valves at the same diameter. This significantly reduces costs and increases installation flexibility for users with budget constraints or limited installation space.

2. Leakage Performance

Although single-seat control valves have low leakage rates, they cannot achieve zero leakage, which is a disadvantage in applications with strict leakage requirements. In contrast, V-port ball valves can achieve zero leakage, ensuring system safety and reliability.

3. Shearing Capability

The design of V-port ball valves provides good shearing capability, making them suitable for handling media containing particulates. The rotation of the valve body creates a wiping effect, preventing the accumulation of media on the sealing surface and ensuring sealing effectiveness, which is particularly important in pulp transportation processes.

4. Application Scenarios

Due to their excellent regulation and cutoff performance, V-port ball valves are suitable for industries such as chemicals, pharmaceuticals, and papermaking, especially when dealing with fluids containing particulates or impurities. Single-seat control valves are commonly used for general fluid flow control, suitable for gases, water, and low-viscosity liquids, and are widely applied in HVAC and water treatment.

Conclusion

Selecting the right fluid control valve is crucial for optimizing system performance in various industrial applications. V-port ball valves are increasingly becoming the preferred choice for many users due to their outstanding regulation capabilities, zero leakage characteristics, and excellent adaptability to media containing particulates. Meanwhile, single-seat control valves, with their simple design and reliable operation, still hold a place in many traditional applications. Users should consider the actual working conditions, fluid characteristics, and economic budget comprehensively to choose the most suitable type of valve for efficient and reliable fluid control.