Difference Between Gate Valve and Ball Valve: How |Pneumatic

Difference Between Gate Valve and Ball Valve: How to Choose the Right Valve?

Sep.19.2024

In the industrial sector, gate valve and ball valve are common fluid control devices, each playing a vital role in various applications. However, there are significant differences between these two types of valves. This article will elucidate the distinctions between gate valve and ball valve and provide some recommendations for selecting the appropriate valve for your needs.

Part 1 Structure and Working Principles of Gate Valve and Ball Valve
1. Gate Valve: A gate valve controls fluid flow by raising and lowering a gate or wedge-shaped disc within the valve. It comprises a valve body, gate, stem, and sealing rings. When the gate is raised, fluid can flow through the passage in the valve body; when the gate is lowered, fluid flow is obstructed. Gate valves are characterized by their simple structure, excellent sealing performance, high flow resistance, and are suitable for controlling low-pressure, large-diameter, and viscous fluids.

How does a gate valve work - Fleyenda Flow

2. Ball Valve: A ball valve controls fluid flow by rotating a spherical ball within the valve. It consists of a valve body, ball, stem, and sealing rings. When the stem rotates, the hole in the ball aligns with the passage in the valve body, allowing fluid to pass through or blocking it. Ball valves are known for their simple structure, excellent sealing performance, low flow resistance, and are widely used for controlling high-pressure, high-temperature, and corrosive fluids.

Part2 The Main Differences Between Gate Valve and Ball Valve in High Temperature and High Pressure Applications

NO.	Valve Component	Ball Valve	Gate Valve
1	Valve Core	The valve core of a ball valve is a sphere. Due to its fixed ball structure, the valve remains stationary under high-pressure conditions, especially when closed. The upper stem and lower support shaft help distribute some of the pressure from the medium, preventing the ball from shifting downstream. As a result, the downstream valve seat experiences relatively low pressure, reducing friction and wear during operation. This design extends the valve's lifespan, making it particularly suitable for frequently operated valves.	The valve core of a gate valve is a wedge-shaped or parallel gate plate, and it does not have a lower support shaft. In high-pressure applications, especially when closed, the gate plate endures significant pressure from the medium. Due to its flat gate plate structure, all the medium pressure acts simultaneously on the gate plate, causing it to press tightly against the downstream valve seat. Excessive pressure on the vertical surface of the gate plate can deform it, regardless of whether it is a wedge or parallel double gate plate. Therefore, opening the valve requires overcoming substantial friction, leading to greater wear on the valve seat and a shorter valve lifespan.
2	Valve Seat	The valve seat of a ball valve contains a spring, and the sealing design of the valve seat prevents debris from entering the valve seat area. Under the action of the spring, the valve seat remains in constant contact with the ball. Therefore, during valve operation, the seat performs a scraping action that removes debris adhering to the valve core, ensuring long-term sealing performance. Particularly in high-temperature and high-pressure applications, materials with the same thermal expansion coefficient are selected for the valve seat, valve body, and ball. The spring-loaded valve seat design ensures that large temperature differences and drops do not affect the valve's operation, preventing the valve from seizing.	The valve seat of a gate valve is narrow. In high-temperature applications, when the valve is closed, the lack of medium flow causes a temperature drop, resulting in the valve seat contracting and exerting significant pressure on the gate plate. Reopening the valve requires considerable torque to overcome this pressure, leading to substantial damage to the valve seat and reducing its lifespan, thus affecting the overall valve lifespan. Additionally, the weight of the gate plate itself during closure causes a significant impact force on the valve, resulting in loud noise.
3	Stroke	The ball valve has an angular stroke, requiring less installation space and height.	The gate valve has a linear stroke, requiring more installation space and height.
4	Actuator Mechanism	Due to the fixed ball design, the torque required for opening and closing is small, allowing for a correspondingly smaller actuator.	Due to the significant pressure of the gate plate against the valve seat, overcoming this high friction requires substantial torque, necessitating a larger actuator.
5	Medium Flow Direction	Bidirectional, no installation flow direction issues on site.	Generally unidirectional.
6	Service Life	Long	Shorter relative to ball valves.
7	Maintenance	Generally, maintenance is not required, especially for the valve ball and seat, as they experience minimal wear and typically do not need replacement within 5 years.	Due to significant wear on the valve seat, regular maintenance is required.

Part3 Gate Valve and Ball Valve Differences in Application Scenarios

1. Gate Valve: Gate valves are suitable for scenarios requiring strict fluid shut-off, especially when strict fluid flow direction is required. Due to their lower flow capacity, gate valves incur greater pressure loss when fluid passes through them, making them relatively limited in flow control and fluid shut-off. Gate valves are widely used in industries such as water supply and drainage, sewage treatment, and fire protection systems.

2. Ball Valve: Ball valves are suitable for scenarios requiring rapid fluid shut-off, especially when strict fluid flow direction is not required. Due to their higher flow capacity, ball valves incur minimal pressure loss when fluid passes through them, giving them an advantage in flow control and fluid shut-off. Ball valves are widely used in industries such as petroleum, chemical, metallurgy, and power generation.

Part4 Gate Valve vs. Ball Valve: How Do I Choose the Right Valve

The selection between gate valves and ball valves often perplexes users due to their similar functionalities when employed as control valves, with only structural differences setting them apart. Today, this article aims to delve into this matter. However, before we proceed, it's imperative to clarify that there isn't a notion of one valve being inherently superior to the other when it comes to installing gate valves or ball valves before or after control valves. The choice depends on the specific circumstances and operational conditions of the user. Let's first briefly understand the characteristics of gate valves and ball valves.

In terms of functionality, gate valves can be installed before or after control valves and are primarily used in water and hot water pipelines, commonly referred to as water valves. They are generally not suitable for steam pipelines because the gate is difficult to open under high steam pressure, and they are also not suitable for pipelines with sediment deposits as sediment accumulation in the gate groove can result in inadequate closure. The gate valve's closing element is the gate, which moves perpendicular to the direction of fluid flow, allowing only full opening and closing without the ability to regulate or throttle flow. Ball valves, on the other hand, can also be installed before or after control valves and are mainly used in pipelines for shut-off, distribution, and altering the direction of fluid flow. They feature a 90-degree rotational action, with the closure element being a spherical ball with a circular through-hole or passage along its axis.

In terms of advantages, gate valves excel in low resistance, compact size, and affordability. Ball valves, on the other hand, offer superior fluid control characteristics compared to gate valves. They require only a 90-degree rotation and minimal torque to achieve a tight closure, making them ideal for switching and shut-off applications.

From the above discussion, we can conclude that both gate valves and ball valves can be used before or after control valves, and neither is particularly suited for flow control applications. However, ball valves offer slightly better fluid control characteristics and sealing performance compared to gate valves. Yet, in practical installation cases, gate valves are more commonly chosen by users. Why is this the case? Here are some specific reasons:

1. Ball valves can be cumbersome to operate and have stringent sealing surface requirements. The sealing of ball valves demands strict manufacturing processes, and selecting the wrong manufacturer can easily lead to internal leakage issues, resulting in relatively higher costs, especially for large-diameter ball valves. In contrast, gate valves are cost-effective, offer excellent sealing, require less effort to operate, and provide maximum flow channels without resistance when fully open.

2. Ball valves may experience seizing if left unused for extended periods.

3. Ball valves have higher requirements for the medium. For instance, media containing a high fiber content or oxygen can only be handled using ball valves.

In summary, the main differences between ball valve and gate valve lie in factors such as the valve core, seat, stroke, actuator, medium flow direction, and maintenance. Generally speaking, when considering whether to install a gate valve or a ball valve before or after a control valve, the choice depends on economic factors. Gate valves are preferred due to their lower cost; they are much cheaper. Gate valves are suitable for use in large-diameter, low-pressure oil, steam, and water pipelines. On the other hand, if sealing is a primary consideration, ball valves should be chosen. Ball valves are suitable for applications where there are high requirements for leakage class and are suitable for rapid opening and closing. They have superior quality and lifespan compared to gate valves.

With 19 years of experience in valve research and production in China, Fleyenda Flow can provide you with one-stop procurement services and engineering project services. If you have any questions about whether ball valves or gate valves are suitable for your application, please contact us here for more information or consult with our experts.