What are Ball Valves
A ball valve has a spherical disc or ball and a central channel through the middle that rotates to open and close the valve. Attached to its center is a hole or port that, if aligned with both ends of the valve body, enables the flow of fluids. Ball valves allow fast opening, with only a half-turn operation that either opens or shuts the valve. This is why they are ideal for frequent on/off tasks.
What are Gate Valves
A gate valve has a flat rectangular or circular plate that sits and closes across the pipeline. When fully retracted, the gate opens wide to allow the maximum through flow to occur in the valve.
Gate valves have an excellent shut-off when closed; however, some are known to leak when opened partially. They are free-flowing designs typically applied in fully open or fully closed hydrant services and should never be used to control or restrict flow.
Key Differences Between Ball Valves vs Gate Valves
Now that we have their definitions and functions sorted, let’s look at their differences. They are:
Are Ball Valves Better than Gate Valves
Ball valves are often better than gate valves because of their fast operation, less flow resistance and ease of handling. However, some key considerations that can help you make a better choice between the two are:
1. Frequent On/Off Operation:
If you need to turn the valve often, choose a ball valve. The rotary ball design enables the ball valves to open and shut at very sharp angles of 90 degrees. In places where the valves are frequently cycled, this is beneficial in the long run because it does not wear out the valve as quickly as a gate valve.
If you need a good seal and rarely use the valve, then opt for a gate valve.
2. Space Limitations:
If you have space restrictions, ball valves are the right choice. Their small diameter and low mass make them useful where the space available for valve installation is restricted. Select a gate valve if you need a tighter seal and space, isn’t a problem.
3. Maintenance:
Ball valves are easier to maintain without having to be entirely removed from the pipeline. This saves time and cost when maintenance is necessary due to demand.
4. Threaded Connections:
Ball valves are dominant due to the availability of threaded end connections. Gate valves are usually of flanged end types. Consider your connection type before choosing.
5. Regulating/Throttling Flow:
The ball's round shape makes it unsuitable for precise flow regulation at any particular level of demand. Leaks from partial openings also expose the ball and seat to cavitation forces that may damage them. If precise flow is a concern, opt for a gate valve.
6. Shutting Off Flow:
When shutting off the liquid is necessary and no leakage is allowed, a gate valve is worth it. Pressure-reducing valves are also used before pumps and equipment and gates valves are used as isolation valves. Ball valves are not ideal for such situations.
The right valve for an application is always determined by the needs and conditions required. Weigh your requirements and carefully plan your valve selections before settling on one.
FAQs
1. Which is better, a ball valve or a gate valve?
The better option between a ball valve and a gate valve depends on its application. Ball valves close with a simple 90-degree turn. It is a great option for systems needing fast flow control. A gate valve is best when you need gradual control over the flow of water.
2. When not to use a ball valve?
Do not use a ball valve in high-temperature or high-pressure applications. Also, it is designed for fully open or closed positions. So, it is not ideal for throttling or regulating flow.
3. When should you use a gate valve?
Use a gate valve in systems where slow, gradual opening or closing is needed. It helps prevent water hammer or pressure surges.