Gate valves may not be used as often as they were in the past since ball valves started becoming more and more popular, but for certain applications, gate valves are perfect for the job. Irrigation applications still use gate valves as there are still strong benefits that gate valves can offer that Industry.
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In this post, we will take a look at the difference between gate valves and knife valves and explore why gate valves are still popular in certain applications. Let's get started.
Gate Valves and Knife Valves
Gate valves and knife valves are linear motion valves, which include a flat closure element called a gate. The gate inside the valve slides up and down by turning a hand wheel counter clockwise to open and clockwise to close. For knife valves, you simply slide the gate by pushing or pulling the handle. Both valves move the gate into the flow stream to stop the flow of fluid completely. To explore what the markings found on gate and ball valves mean, check out our blog post, How to Understand Ball Valve Markings.
Gate and Knife valves are designed to minimize pressure drop across the valve. In the fully opened position, the diameter of the opening that the liquid passes through is equal to that of the pipe and the direction of flow is not changed.
Applications & Strengths
Gate valves can be found anywhere an economical shut off is required. Gate valves are ideal for any application that involves slurries as the gate can cut right through. Gate valves are also common in applications using liquids like heavy oils, light grease, varnish and other non-flammable liquids.
Irrigation Applications
Gate valves are perfect for irrigation systems where high flow rates are required. Gate valves are slow closing as it takes several revolutions to open or close the gate, therefore flow is started and stopped slower than ball valves. Gate valves are extremely common in Irrigation applications because the speed of closing is not as essential as strength to support a high flow rate.
Gate Valve Limitations
Most gate valves have metal to metal seats which doesn't create a positive seal and can sometimes cause leaks, whereas ball valves shut tight. Gate valves also have a tendency to seize up if not used over a certain period of time, leading to leaks at the stem packing.
As seen in the picture above, gate valves tend to be bulkier compared to ball valves. They stick out more, which is not ideal for tight spaces. For some applications, ball valves would be the better choice as they can offer a leak free seal. For more information on ball valves, check out our post, What the Heck is a Ball Valve?
Throttling (Restricting Flow)
Gate valves can be used wherever throttling capabilities are desired however, this is not typically recommended as erosion of the seat and disc occur due to the vibrations of the disc resulting in the valve leaking over time.
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In Summary:
Although gate valves might not be the most favoured valve on the market, they are still a suitable option for certain functions. Be aware of location and the situation for which you require a valve to determine which style of valve will work the best for you.
Have further questions about this subject?
Head over to Boshart's Knowledge Base: technical product information, guidelines, and more.
As we mentioned, ball valves operate by rotating a ball 90° while gate valves are controlled by moving a gate up or down. Because of their design, ball valves can perform an almost immediate shutoff, whereas gate valves are not able to act as quickly. This makes ball valves a better choice for applications where fast cycle speed is desired.
The 90° operation of ball valves makes them faster to cycle, both manually and with an actuator. This is a benefit in most instances but can potentially cause water hammer in high-pressure applications. If the pressure is high enough, the pipe could weaken or even break, which is why users of manual ball valves should turn the levers slowly to avoid water hammer.
Applications & Use Cases
Gate Valve Uses
Ball Valve Uses
Shutoff and isolation service for:
- Wastewater Plants
- Power Plants
- Mining
- Process Plants
- Large Water Supply Lines
Gate valves are commonly found in older home plumbing systems.
On/off control for specialized industries including:
- Oil & Gas
- Food & Beverage Equipment
- Automotive
- Vehicle Wash Systems
- Power Processing
- Pharmaceutical
- Chemical Admixtures & Treatment
- Irrigation & Water Treatment Equipment
- Manufacturing Facilities
Ball valves are also found in newer home plumbing systems.
Cost
In the gate valve vs. ball valve debate, cost is a major differentiating factor. Up front, gate valves are less expensive than ball valves, but they can be more susceptible to corrosion which means they will need repairs and replacement more frequently. Ball valves have a higher initial cost, but they are the better choice for longevity since they are more durable and highly effective at forming tight seals.
Maintenance
As we just discussed, gate valves are, in general, less durable than ball valves. In moderate or high cycle applications, gate valves will require routine maintenance or replacement. Most ball valves are designed to be maintenance-free and should be replaced rather than repaired. Three-piece ball valves, however, are designed so that the valve seats and seals can be easily replaced without removing the valve from service. This is why 3-piece ball valves are often used in high cycle or high pressure applications where valve seal failure is likely to occur more quickly. However, 3-piece ball valves typically come with a higher up-front cost than the more popular 1-piece or 2-piece body constructions.
When you Should Use a Gate ValveGate Valve - BoshartU
Gate valves may not be used as often as they were in the past since ball valves started becoming more and more popular, but for certain applications, gate valves are perfect for the job. Irrigation applications still use gate valves as there are still strong benefits that gate valves can offer that Industry.
In this post, we will take a look at the difference between gate valves and knife valves and explore why gate valves are still popular in certain applications. Let's get started.
Gate Valves and Knife Valves
Gate valves and knife valves are linear motion valves, which include a flat closure element called a gate. The gate inside the valve slides up and down by turning a hand wheel counter clockwise to open and clockwise to close. For knife valves, you simply slide the gate by pushing or pulling the handle. Both valves move the gate into the flow stream to stop the flow of fluid completely. To explore what the markings found on gate and ball valves mean, check out our blog post, How to Understand Ball Valve Markings.
Gate and Knife valves are designed to minimize pressure drop across the valve. In the fully opened position, the diameter of the opening that the liquid passes through is equal to that of the pipe and the direction of flow is not changed.
Applications & Strengths
Gate valves can be found anywhere an economical shut off is required. Gate valves are ideal for any application that involves slurries as the gate can cut right through. Gate valves are also common in applications using liquids like heavy oils, light grease, varnish and other non-flammable liquids.
Irrigation Applications
Gate valves are perfect for irrigation systems where high flow rates are required. Gate valves are slow closing as it takes several revolutions to open or close the gate, therefore flow is started and stopped slower than ball valves. Gate valves are extremely common in Irrigation applications because the speed of closing is not as essential as strength to support a high flow rate.
Gate Valve Limitations
Most gate valves have metal to metal seats which doesn't create a positive seal and can sometimes cause leaks, whereas ball valves shut tight. Gate valves also have a tendency to seize up if not used over a certain period of time, leading to leaks at the stem packing.
As seen in the picture above, gate valves tend to be bulkier compared to ball valves. They stick out more, which is not ideal for tight spaces. For some applications, ball valves would be the better choice as they can offer a leak free seal. For more information on ball valves, check out our post, What the Heck is a Ball Valve?
Throttling (Restricting Flow)
Gate valves can be used wherever throttling capabilities are desired however, this is not typically recommended as erosion of the seat and disc occur due to the vibrations of the disc resulting in the valve leaking over time.
In Summary:
Although gate valves might not be the most favoured valve on the market, they are still a suitable option for certain functions. Be aware of location and the situation for which you require a valve to determine which style of valve will work the best for you.
Have further questions about this subject?
Head over to Boshart's Knowledge Base: technical product information, guidelines, and more.
Gate Valves vs. Ball Valves: How to Choose the Right One
As we mentioned, ball valves operate by rotating a ball 90° while gate valves are controlled by moving a gate up or down. Because of their design, ball valves can perform an almost immediate shutoff, whereas gate valves are not able to act as quickly. This makes ball valves a better choice for applications where fast cycle speed is desired.
The 90° operation of ball valves makes them faster to cycle, both manually and with an actuator. This is a benefit in most instances but can potentially cause water hammer in high-pressure applications. If the pressure is high enough, the pipe could weaken or even break, which is why users of manual ball valves should turn the levers slowly to avoid water hammer.
Applications & Use Cases
Gate Valve Uses
Ball Valve Uses
Shutoff and isolation service for:
- Wastewater Plants
- Power Plants
- Mining
- Process Plants
- Large Water Supply Lines
Gate valves are commonly found in older home plumbing systems.
On/off control for specialized industries including:
- Oil & Gas
- Food & Beverage Equipment
- Automotive
- Vehicle Wash Systems
- Power Processing
- Pharmaceutical
- Chemical Admixtures & Treatment
- Irrigation & Water Treatment Equipment
- Manufacturing Facilities
Ball valves are also found in newer home plumbing systems.
Cost
In the gate valve vs. ball valve debate, cost is a major differentiating factor. Up front, gate valves are less expensive than ball valves, but they can be more susceptible to corrosion which means they will need repairs and replacement more frequently. Ball valves have a higher initial cost, but they are the better choice for longevity since they are more durable and highly effective at forming tight seals.
Maintenance
As we just discussed, gate valves are, in general, less durable than ball valves. In moderate or high cycle applications, gate valves will require routine maintenance or replacement. Most ball valves are designed to be maintenance-free and should be replaced rather than repaired. Three-piece ball valves, however, are designed so that the valve seats and seals can be easily replaced without removing the valve from service. This is why 3-piece ball valves are often used in high cycle or high pressure applications where valve seal failure is likely to occur more quickly. However, 3-piece ball valves typically come with a higher up-front cost than the more popular 1-piece or 2-piece body constructions.