Views: 37 Author: Site Editor Publish Time: 2023-01-31 Origin: Site
Gate valves and ball valves are the most commonly used flow control valves in the market. They are generally used to control the flow of liquid and gases. Although they are used in similar settings, there are a few important differences between these two valves. We discuss the differences between gate and ball valves and how to choose between them.
What is a ball valve?
Ball valve is a kind of quarter-turn valve. There is a sphere inside the valve body. The sphere rotates a quarter turn with the valve stem to open or close the valve. The inside of the sphere is hollow, which allows fluid to transport.
According to the design, the ball valve can be divided into two-way, three-way or four-way ball valve, which is used for circulation, cut-off, changing the flow direction of the medium, confluence and divergence.
Ball valves are generally used in low-pressure industries. If you need to use it in the high-pressure industry, you need to customize the ball valve that can withstand high pressure.
The ball valve can be made of plastic, brass, stainless steel or carbon steel.
Due to the limited size range of the ball valve, it will be suitable for use in small pipelines, such as water treatment industry, power plant, boiler industry, shipbuilding industry and so on.
What is a gate valve?
The gate valve is a linear motion valve. The valve flap moves up or down to open or close the valve. Gate valves can also be divided into knife gate valves according to their design. The gate valve is a two-way valve with no flow direction requirements.
The gate valve can only be fully opened or fully closed, so the gate valve can only be used for flow and cut-off, and cannot adjust the flow. The gate valve is not easy to be blocked, so it is very suitable for cement plants, paper and pulp and so on.
The gate valve can be made of plastic, cast iron, stainless steel or carbon steel.
The gate valve has a very wide range of sizes, so it can be used in any industry, such as food processing plants, wastewater treatment, oil and gas, and automation industries.
Selection criteria
The following criteria can be considered before selecting between a ball valve and gate valve:
Ports: A gate valve has 2 ports, while a ball valve can have more than 2 ports.
Flow Capacity: A gate valve can provide larger flow capacity than a ball valve as they are typically offered in larger diameters.
Opening and closing speed: A ball valve is better suited for applications that require faster opening and closing speed or during emergencies due to its quarter turn on/off operation. A gate valve requires more than a 360° turn, making it slower than a ball valve to operate.
Sealing: A ball valve provides a tight seal and has complete shut off characteristics as compared to a gate valve. Therefore, ball valves are better suited for applications like natural gas where a proper seal long-term is important.
Pressure: Both ball valves and gate valves are suitable for low pressure applications. However, for high pressure applications a gate valve is better suited. This is due to the fast opening/closing of the ball valve that may cause a water hammer.
Cost: A ball valve is generally more expensive than a gate valve of the same specifications. However, a ball valve is typically more durable and requires less maintenance compared to a gate valve. So, a ball valve may be more economical long-term.