Gate Valves VS Ball Valves

Now that you know what gate valve and ball valve are let’s talk over the aspects that make them unique. Despite sounding quite similar, the gate valve and ball valve differ in a few ways. Most of the customers get confused while selecting between them.

Design and Construction

Although the gate valve and ball valve serve the same purpose, they differ significantly in their design and structure.

The ball valve is smaller than the gate valve, but it requires more place for actuation because its lever needs to be rotated at 90° degree to operate. While a gate valve, despite being larger requires less space for actuation because it is performed through a handwheel that can be rotated in less space

To regulate the flow of liquid, the ball valve has a small sphere while the gate valve possesses a rectangular gate or wedge attached to the stem for this purpose. In addition to this, the gate valve does not offer quick shutoff function like a ball valve. But it provides more hold over the media flow and pressure of the flow, which makes them better in conditions of high-water pressure.

Ball valves are long-lasting compared to a gate valve because of the gate valve’s high susceptibility to corrosion. This problem can be solved by choosing a different material like stainless steel and brass.

Construction material

Ball valve

• Stainless steel grade 316 or CF8M for ball
• Carbon steel grade WCB and LCB
• PVC (Polyvinyl chloride)
• CPVC (Chlorinated Polyvinyl chloride)

Gate valve

• Cast iron
• Ductile iron
• Alloy steel
• Forged steel
• Cast carbon steel

Working of Gate valves

The working of gate valves is very straightforward. They may have many sizes, materials, temperature, and pressure ratings and designs, but the gate valve’s basic working principle is the same in all the models. To open the gate valve, you must rotate the handwheel anti-clockwise and clockwise to close the valve. The inner gate or wedge moves upwards to permit the media to flow without resistance. A semi-open position cause throttling, but there is a great chance of disc damage.

Working of Ball valves

It is a shutoff valve that regulates the media flow through a ball having a bore. By rotating the shaft or stem by 90° degree (quarter turn), perpendicular to the ball, media flow can be blocked and opened. When the stem is at the right angle to the disc, the ball’s bore is aligned with the pipeline, and media is allowed to flow. It uses media pressure to make a tight seal.

Ports

Gate valves are usually bi-directional, having two ports, one for the inlet and another for the outlet. These ports are threaded or flanged according to the valve’s type and application.

Ball valves can have two or more, threaded or flanged ports. Ball valves with three ports are employed for mixing and deflecting the liquid. Moreover, a ball valve can be full-port or reduced-port. A full-port ball valve contains a ball with a bore size equal to the pipe’s diameter with which the valve is attached while a reduced-port features a ball with a bore size less than the pipe’s diameter.

Flow characteristics

Gate valves are operational only in the fully open and closed state. A partially open gate valve can cause throttling which can damage and affect its performance. These valves are suitable for media flowing in a linear direction.

Ball valves are very good at regulating the flow of gases and other light media because they form a tight seal efficiently. They are suitable for conditions where you need to start and stop the flow instantly. Ball valves are designed to exhibit a flow characteristic known as “Modified equal percentage”.

Actuation

Gate valves are principally actuated by handwheel because gate valves are used for high-temperature and high-pressure applications. Handwheel offers better control over opening and closing. Since the handwheel is rotated to turn on and off the valve, it isn’t easy to notice whether the valve is open or close. Moreover, it is hard to operate during high-pressure operations as it requires more energy.

Ball valves can be actuated manually, electrically or, pneumatically. Manual ball valves are used generally because they are cheaper and durable. It is held perpendicular to the pipeline and is easy to operate furthermore they allow an easy visual indication of valve state. Moreover, they are actuated faster than gate valves.

Gate valve costs VS Ball valve costs

Ball valves are more expensive than gate valves because they are more versatile and reliable. Ball valves are worth all the money as they are durable and function for a more extended period.

Both valves advantages and disadvantages

• Gate valve works slowly as we have to rotate the stem to 360° to open or close the gate.
• The slow operation also reduces the risk of water hammer.
• It’s challenging to identify if the valve is opened or closed.
• Gate valves are less expensive.
• Gate valves are more vulnerable to a leak and stem rust.
• Works better with the pipes bigger than two bores.

Ball Valve Advantages and disadvantages

• Ball Valve works fast, as we have to rotate the stem to 90° for opening and close the valve.
• Fast opening causes water hammering.
• Open and closed can be visually detected, the valve is close when perpendicular to the pipe and open when parallel to the pipe.
• The ball valve is expensive than the gate valve but lasts more than the gate valves.
• Better for pipes less than two bores.
• Provide a tight seal and less prone to leakage or damage.

Gate valves applications

Following are the typical applications of gate valve:

• Gate valves are used in large supply water systems because they have a linear flow and low resistance.
• They are found in old plumbing systems.
• They have applications with slurries and viscous mediums.
• They are also used in high temperature and high-pressure conditions such as in power plants and mining fields.

Ball valves applications

Some typical applications of the ball valve are:

• Ball valves are favourable in gaseous, air, and vapour systems that require bubble-tight service.
• They are applicable in cooling water and feed water system.
• In instrument root valves
• Petrochemical and gas industries
• One other application of ball valve is the fire protection system.

Ball valves are not used in food and pharmaceutical applications because they can cause contamination as they are challenging to wash. In contrast, gate valves have been used in the food and pharmaceutical field because they are easy to clean.

These are the things that you must consider before choosing between the ball valve or gate valve. Usually, the gate valve is used for liquids, and the ball valve is used for gases.

Flow Rate: If you want a large flow, the gate valve will be a better choice because it is usually used on a piper with a large diameter.

Opening and Closing speed:  For faster opening and closing, you must use a ball valve because you can open a ball valve by quarter rotation then gate valve.

Pressure: For fast pressure application, you must use a gate valve because the ball valve can cause hammering. Both valves work exceptionally with low-pressure applications.

Gate Valve VS ball Valve Price: Ball valve is costly than the gate valve, but in a long run ball valve is cheaper as it is stronger and more durable than the gate valve.

Sealing: If the pipe is carrying a harmful gas, then the ball valve has to be your choice because it tightly seals the valve.