Difference between Gate Valves and Ball Valves

One of the most important components of a functional plumbing system is the valves it contains. Valves allow for the start and stop of the flow of liquid, and they need to work well to prevent leaks and unwanted flow. While there are a number of valve types on the market, two of the most common are the ball valve and the gate valve. Here's what you need to know about these two valve types.

What Is a Gate Valve?

A gate valve gets its name from the internal mechanism that enables the flow of water. This mechanism looks like a tiny gate that moves up and down on a stem, which is connected to the handle. The handle is a screw handle that moves the gate up and down, opening and closing the valve as needed. They are best used in on/off applications where the valve is used infrequently. They are sometimes found in home plumbing systems, though ball valves are becoming more popular in this area. They are also commonly found in the oil and gas industry, pharmaceuticals, manufacturing, automotive, and marine applications. They can be used in high pressure and high temperature environments, so are often found in manufacturing.

Gate valves have one major advantage over ball valves. Because the opening and closing mechanism is slow, they can't cause a water hammer. For this reason, some municipalities require the valve nearest to the water meter to be a gate valve.

However, gate valves have disadvantages as well. The screw mechanism that opens and closes the valve can easily fall victim to corrosion. Once corroded, the valve won't work properly. Gate valves should be used in fully open or fully closed positions, but it is possible on some models for the valve to be stuck partially open or partially closed. This causes vibration of the gate, which can damage the valve. Gate valves can be hard to operate by those with disabilities, and they don't provide a visual clue to the "on" or "off" position.

Types of Gate Valves

While the basic function of a gate valve is the same regardless of the type, you will find a number of valve types on the market. Your application will determine which type you need.

Brass Gate Valves - (view products)

Brass gate valves are highly durable and work well in applications where corrosion is a serious concern. This material tolerates high temperatures well, so it is commonly used in manufacturing applications.

PVC Gate Valves - (view products)

PVC gate valves are flexible, affordable, and lightweight. They are commonly found in cold-water home applications, where high temperatures and high pressure are not a problem.

Stainless Steel Gate Valves - (view products)

Stainless steel is rust-free and has a low corrosion rate, so it's a great choice for gate valves used in areas where corrosion is a serious problem. Stainless steel won't leach into water, so it can be used in areas where metal contamination is a serious risk, like home drinking water. This is a strong factor and can withstand human error, weather, and even damage from tree roots.

What Are Ball Valves?

Ball valves shut off the flow of water using a small sphere, or ball, inside the valve. The sphere has an opening inside. When in the "on" position, the opening is in line with the pipe, allowing water to flow freely. When in the "off" position, the opening is perpendicular to the flow of water, stopping the flow completely. In a ball valve, flow is controlled with a lever. Placing the lever perpendicular to the pipe allows water to flow. Moving it at 90-degree angle stops the flow.

Ball valves have several advantages. They are easy to turn on and off quickly, and can be used by individuals who cannot maneuver a wheel-operated valve due to disability. They allow the user to tell at a glance if the valve is open or not. They are durable, rarely freeze even with years of use, provide reliable service, and are extremely versatile. Ball valves are used in home plumbing, industrial applications, oil and gas applications, marine applications, pharmaceuticals, and many other fields.

The primary disadvantage of the ball valve is the requirement of space. In tight applications, you may not have 90 degrees to turn the valve's handle. Also, in rare instances a ball valve can create a water hammer condition.

Types of Ball Valves

Like gate valves, ball valves can be made from a number of materials.

PVC Ball Valves - (view products)

PVC ball valves offer the affordability and flexibility of PVC piping and can be used in areas where high pressure and high heat are not a concern.

Brass Ball Valves - (view products)

Resistant to high temperatures, brass ball valves are great for manufacturing needs and hot water applications.

Bronze Ball Valves - (view products)

Bronze pvc valves are often found on ships because of the low risk of corrosion with the constant exposure to seawater.

Stainless Steel Ball Valves - (view products)

Stainless steel is prized for its strength, and these ball valves are used in applications with high pressure and temperature. It also won't rust or corrode, so it can be used in water and corrosive chemical applications.

Both ball and gate valves serve a purpose. By choosing the right one for your application, you can be certain that your plumbing system will serve you well.

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