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What Are Ball Valves & How Do They Work?

What Are Ball Valves & How Do They Work?

From plumbing to cooling, piping systems need a way to stop and start the flow of materials - which is where a ball valve comes in handy. But what is a ball valve, and how does it work so efficiently?

Keep reading to learn more from the team at The Hosemaster…

What is a ball valve?

First things first, what is a ball valve?

A typical valve is designed to control, direct, or regulate the flow of a medium (usually liquid). It does this by opening and closing to obstruct or allow the material to flow through the system. 

Ball valves are a common type of fitting that use a ball with a bore through it to allow liquids or gases to flow through the middle. By rotating the ball, you can control whether the material can pass through the valve into the rest of the system.

A ball valve

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When would you use a ball valve?

Ball valves are a simple but effective way to control the passage of liquids or gases through a system. They’re primarily suited to on/off applications because of the direct nature of the ball - it can either let materials through or not - and tend to struggle in situations where you need to regulate the amount of a medium.

Their design means that ball valves are perfect for plumbing, gas line management, domestic appliances, and industrial processes (like cooling systems) where you need to stop and start the flow of specific liquids or gases. Ball valves are excellent as part of an emergency shut off protection system because they can be activated quickly to stop materials moving.

Note - industrial ball valves are usually made of different materials to survive higher temperatures and pressures.

You can also use ball valves to control the direction of a material. Different designs can help you redirect the flow to where you need it, and help make your piping systems more efficient.

How does a ball valve work?

The design of a ball valve is what makes this type of fitting so efficient, but what is so special about it - and how does it work?

Labelled diagram of a ball valve

As you can see in the diagram, ball valves are composed of a rotary ball within the valve body (often also called housing). The majority of ball valves use a ‘floating ball’ construction, which is where the ball ‘floats’ and is supported by o-rings on either side (called the seat). Alternatively, high-quality or industrial units may use a ‘trunnion style’, which has additional support at the top and bottom to reduce the load on the seat.

Within the valve, the ball has a bore, or hole, through the centre, which effectively makes it hollow. When the valve is open, the bore is facing the direction of the pipes. When it’s closed, the sides of the ball obstruct the passage of the medium and prevent any from escaping.

The handle is attached by the stem, which sits onto the top of the ball. Some, like the one in the image above, sit in a rectangular groove. This offers you more torque to move the handle, with less risk of deforming or damaging the ball.

Note - ball valves are ¼ turn valves, similar to plug and butterfly valves.


The number of ports on your ball valve can have an impact on how it works within a system. The most common type has two ports (like the diagram) which controls the flow of materials in one direction. 

Three port ball valves can help you send materials around corners with an L-shaped valve, where turning the handle will control whether the flow goes left or right. Alternatively, a T-shape fitting allows you to direct a medium across multiple directions. This is useful to make piping systems more efficient, or when you need to design your pipes within a specific space allowance.

A three way ball valve

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Bore shape

Bore shape and size will also have an influence on how a ball valve works within a system. Reduced bore ball valves are designed so that the hole is slightly narrower than the pipes around it. This introduces a small amount of friction as the medium flows through the system (but not enough to make an impact). A full bore has the same diameter as the surrounding pipe, which means there is no loss of speed or pressure because of friction. Lastly, some bores are V-shaped, which can help to control the flow rate slightly when you rotate the ball.


Obviously, the handle is important in how a ball valve works because it controls whether the fitting is open or closed. The primary thing to know about ball valve handles is that, when properly installed, the handle should lie parallel with the pipe in the open position, and perpendicular to the pipe when closed. This design acts as a visual cue to let you know when the valve is ‘on’ or ‘off’.

Note - ball valves can have a variety of handles, including; lever, T-handles, or they can be operated pneumatically or electrically.


Whilst the body, or housing, of a ball valve doesn’t affect the way it works, it’s important to understand that this will affect the functionality of the piece within your system. Ball valves come in one-piece, two-piece, or three-piece assemblies.

One-piece units are the cheapest, and suitable for low-demand applications. The two pieces of the housing are pressed or welded together, which means they can’t be cleaned or repaired easily.

Two-piece ball valves can be disassembled for cleaning and maintenance, however they have to be removed from the system entirely. Three-piece ball valves are the most expensive, but the advantage is that they can be serviced in situ.

Three piece ball valve

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Benefits of a ball valve

Ball valves are a small but incredibly useful piece of equipment that can have a big influence on how a piping system works. Their shape and design means there are several benefits to how they work, including:

  • A longer service life - they’re more reliable and durable over time.
  • A higher resistance against contamination, which means they can last for longer, and don’t need replacing or cleaning as often.
  • Quick to operate - ¼ turn handles are quick and easy to use, which makes them perfect for emergency stop or release valves.
  • A low pressure drop, especially with full bore ball valves as the hole is the same width as the surrounding pipes.
  • Minimal maintenance requirements - they don’t need frequent clearing or cleaning, and often still work well after long periods of disuse.
  • No lubrication required, as the design works without it - which cuts down on costs and maintenance time.
  • A reduced chance of leakage as the ball is securely in the valve with nowhere for materials to leak from.

These qualities make ball valves a valuable part of a plumbing or gas maintenance system where you need to control the flow of a medium.

Choose The Hosemaster today

At The Hosemaster, we have decades of experience supplying hoses, connections, and everything you need to get the job done. From plumbing to pneumatics, we’ve got it all - so you can be sure to find quality parts right here.

Plus, we’re always prepared to lend a hand, and answer any questions or queries you have. To speak to a member of our team, contact us via our online form. Or, if you fancy a chat, call us on 01282 604 002.

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