What Are the Different Types of Valves?

Whether you’re transporting gases or liquids, valves are a vital part of any connecting system. But, what are the different types of valves, and how do their designs influence operation? In this guide, we’ll explore several of the more common types of valve and how these can be used across different systems.

What is a valve?

Valves are specific pieces of a pipe system that are designed to control the flow of a material. This medium could be liquid, gas, or even small solids depending on the type of systems put in place within an industry.

The reason valves are incredibly useful is that they allow you to regulate the system during use. The most common type of valves allow you to stop or start the flow of matter, however there are other designs that are able to regulate how much or how little of the material is allowed through the system at once. 

Another useful aspect of valve design is that some are unidirectional. This means that a medium can only move one way through the system (the valve will close otherwise to block the flow). This helps to prevent clogging, or material build-up – which in turn protects your piping system from unnecessary stresses and damages.

Why is using the correct valve important?

Using the correct valve is essential for several reasons. Firstly, valves help to make your system more efficient, which helps to improve the overall performance of your system. The right valve can also ensure everything runs smoothly for longer, saving you money and energy in the long run. Plus, using the correct valve at installation means you don’t have to replace it later, which can cost money and shut off operation during the re-installation process.

Lastly, and perhaps most crucially, having the correct valve is vital because the wrong one can be incredibly dangerous. Whether it’s an incorrect size, improperly fitted, or an inappropriate design, the wrong valve can have wide-reaching and serious consequences – to the safety of yourself, and those around you. This is doubly true for any chemical or hazardous material systems, or those that experience high-pressure conditions, so it’s absolutely vital you make sure you have the right type of valve in place.

Types of valve

Most valves tend to fall into three main categories: rotary, linear, and self-actuated. 

Rotary valves, as the name would suggest, affect medium flow via a rotating closure mechanism. This could be anything from a ball, as with ball valves, to the spinning disc seen in butterfly valves. 

Linear valves also use the movement of an obstacle to stop or start the flow of matter. However, instead of spinning, linear valves have discs or slats that are moved in straight lines (up, down, left, right) to achieve the desired result – as seen in globe or gate valves.

However, both of these require direct intervention to work. This could be through automated systems or manual handling, but they still need something to control when the valve is open or closed. Self-actuated valves on the other hand, do not require direct operation. Instead, they use the material to open or close. For example, relief valves, safety valves, and steam traps automatically release under set conditions in order to reduce pressure within your pipe network.

Now, with all of this in mind, let’s take a closer look at the types of valves that are available for your piping networks. 

Ball valve

Typically used within liquid-handling networks, ball valves are designed to stop or start flow by rotating a ball with a hole through the centre. These are incredibly popular across a variety of industries, including plumbing, cooling valves, and certain domestic appliances. 

One advantage of ball valves is that they’re quick-acting, which is important when you need a quick solution to stop or start the flow of a material. They also have a tight shut off point to prevent leaks, and require little maintenance, which saves you money in the long term. Plus, ball valves are known to have a low pressure drop, which means they don’t increase power needs to ensure the same rate of flow throughout a pipe system.

On the other hand, due to their design they aren’t suited to regulatory applications – they’re largely either ‘open’ or ‘closed’. If used in a partially open form, the seats (where the ball rests within the body of the valve) can deform and cause the ball to lock in one position. There are also temperature limitations depending on the material the valve is made of, as excessive heat or cold can impact the movement of the ball.

For a more in-depth look at ball valves, don’t forget to check out our guide on What Are Ball Valves & How Do They Work?

Gate valve

Gate valves are a type of linear valve that use a barrier (or gate) to block or allow the flow of a medium within a pipe system. These are compact, relatively uncomplicated, and often used in water supply networks because they’re effective at re-routing or isolating the flow of a liquid in order to conduct maintenance or new installations within the system.

Note: the shape of the gate can vary in different designs. For example, knife gate valves have a sharpened disc that can cut through slurry or more viscous materials more effectively to ensure a better seal. This ensures that gate valves are highly versatile, and can be used within networks for a variety of materials.

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One of the main advantages of gate valves, particularly wedge gate valves, is that they’re relatively easy to install. This is because they’re symmetrical, so they don’t have a predetermined flow direction that will affect how they need to be inputted into a network. This also means that they can be used in systems where the flow direction is subject to change. Gate valves offer you a high-performing seal to prevent the movement of a medium.

On the other hand, what you gain in this improved seal quality, you lose in speed. Gate valves are slow to open or close, as the barrier has to travel the width of the valve/pipe – so you should avoid these valves in places or situations when you need a rapid response. Additionally, because of the frequent movement, gate valves are prone to scratches, which can affect the long-term performance of the seal.

Globe valve

Initially named for the shape of the valve body, a globe valve is a valuable part of many industrial systems, including chemical processing plants or wastewater treatment plants. This is because their design makes them excellent at controlled flow regulation.

Within the body of a globe valve, two halves are separated by an incomplete, internal barrier. Using a plug or disc, a gap can be left within the barrier (thus the valve is open), or blocked (closing the valve and stopping flow). More importantly, this design allows you to regulate the flow of a medium, as you can reduce the space it has to flow without fully closing the valve.

Having a controllable valve is an advantage for certain systems. For example, when you want to reduce how much liquid is flowing into an area without shutting operation down completely – like a tap, where you can allow for a trickle or flood of water to be released. Globe valves are also easy to maintain, and highly reliable.

However, globe valves do suffer from head loss. This means that liquids drop pressure as they pass through the valve, which can be an issue in some applications. Globe valves are also relatively heavy, which is something to bear in mind for more delicate networks. Lastly, globe valves are unidirectional. This means they can only control fluid flow in one direction, and will need to be installed properly to make the best use of them.

Needle valve

Similar to a globe valve, needle valves use a type of plug to block a gap within the body of the valve. However, like the name suggests, needle valves have a narrow plunger that's tapered at one end. This allows them to be incredibly precise when it comes to flow regulation, as well as acting as an on/off valve.

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It’s this precision and control that makes needle valves so valuable. With an increased ability to regulate flow rate, needle valves can be more efficient – instead of wasting materials and energy, the control you’re afforded with a needle valve allows you to use exactly what you need. They’re also incredibly reliable and safe because nothing flows when it isn’t meant to, reducing the risks of leaks or dangerous breaks.

However, it’s vital that these valves are used in the right place. As the opening within the valve body is incredibly narrow, this valve is not suitable for high-flow applications – there would simply be too much for the valve to handle. It’s for this reason that needle valves are commonly used within smaller applications, where precision and accuracy are more important. This includes working with chemicals, wastewater treatment, and within food production.

Strainer valve

When it comes to maintaining a pipe network, it’s important that mediums are allowed to flow without obstructions – like those caused by small bits of debris. Whilst small, these bits of rubbish can have big consequences for the integrity and safety of your pipe system, which is why it’s vital to filter them out. 

This is where the strainer valve comes in. Strainer valves have an extra layer, typically made of mesh or perforated metal, that catches larger particles whilst still allowing a liquid or gas to flow through to the next section. These solids can then be disposed of with minimal disruption to your operations.

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There are plenty of obvious advantages to including strainer valves into your pipe network. Firstly, they can help to protect the longevity of your equipment by removing solids before they can cause damage further down the line. They’re also useful for filtering out corrosive particles that could affect the structural safety of your pipes. In addition, strainer valves are highly customisable. Depending on your industry, you may need a finer mesh weave to filter out smaller particles, or more flexible designs to dispose of the waste materials.

However, you need to keep in mind that you will experience a pressure drop as a medium flows through your strainer valve. You’ll also need to complete more maintenance checks on the valve to ensure they’re working efficiently, and take time to clear away the debris collected.

Non-return valve

Non-return valves, aka check valves, are a unidirectional valve designed to prevent backflow by only allowing a medium to flow in one direction. These are vital in systems where pressure may force a material to move in the wrong direction, like in heating systems. The majority of non-return valves work automatically, however there are several mechanisms a check valve can use to prevent backflow, including:

• Swing check valves use a metal flap that swings down into place.
• Piston check valves have a spring-loaded plunger to block travel in the wrong direction.
• Ball check valves have a ball that fits into a gap when flow slows down.
• Tilting disc check valves are similar to the swing mechanism, but are more gentle (with less slamming into place).

Non-return valves are incredibly useful from a safety perspective, both for people operating them and the pipe network itself. Preventing reverse flow protects your pipes from damage, which in turn protects the people working with these systems. Check valves are also relatively small, simple to install, and can save you money and energy over time.

However, it’s worth noting that non-return valves will cause a high pressure drop – which you’ll need to keep in mind when you’re designing your pipe network. They can also require more maintenance to ensure they’re working efficiently. Check valves are also not suitable for manual control, as they work automatically depending on the flow within a system.

Pressure relief valve

Used to control and release the amount of pressure in a system, relief valves play an essential role in a vast array of industries. From chemical treatment plants, to hot water heaters, to hydraulic systems, relief valves protect you, the people around you, and the pipe networks themselves from pressure damage.

Relief valves work automatically; they open when the pressure rises above a certain level to relieve the system, then close again to maintain the desired level. These can be controlled by springs, or connected to pressure gauges that indicate when the valve needs to open/close.

Due to their function, the main advantage of a pressure relief valve is that they work automatically, rather than needing manual intervention. This means that they can ensure pipe networks are running safely – and save you from costly repairs in the future from pressure build-ups.

Of course, there are some disadvantages to relief valves. Releasing pressure causes vibrations, so you need to make sure these are accounted for in your design – to prevent damages or abrasions across the network. They’re also prone to leakage, so require more maintenance to ensure they’re functioning efficiently.

How to choose the appropriate valve

Knowing about valves is the first step in choosing the appropriate one for your needs. To help you make your decision, we’ve pulled together a short checklist of aspects you need to consider when choosing between different types of valve.

• Purpose: the first thing to consider is what you want your valve to do. For example, do you need a valve that can open and close, or something that offers you throttling and flow regulation?
  
  
• Medium: What medium is flowing through your system? Different valve types are suitable for use with solids, liquids, and gases.
  
  
• Material: What is your valve made of? For example, steel is incredibly durable and resilient, bronze is wear-resistant, and brass is resistant to corrosion.
  
  
• Pressure requirements: High pressure or flow systems will need a valve that can withstand the conditions. You’ll also need to consider pressure drop throughout the system.
  
  
• Operation: Do you need a quick shut-off valve? Or an automatic relief valve that doesn’t need manual operation? Considering the operation of your valve is vital to choosing the most appropriate option for your network.
  

Choose the right valve for the job with The Hosemaster

Finding the perfect valve can make your life a million times easier – and here at The Hosemaster, we have plenty of options to ensure you can get the job done right! Explore our excellent range of valves and hoses today to make your piping systems as efficient and long-lasting as possible.

And, with decades of industry experience at our fingertips, our team is always on hand to help you through every phase of your buying journey. All you need to do is ask! Try contacting us online, or give us a ring on 01282 604 002.

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For more useful advice and information, and plenty of buying guides, check out The Hosemaster blog…

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