Air Supply UK: Specialist Compressed Air Engineers

Published: 01/03/2024

What is an air dryer?

Air dryers are essential for many industries and compressed air uses. Dryers remove moisture from compressed air, preventing a build-up of condensation and subsequent damage to your machine. 

If you’re thinking about investing in an air dryer for your compressor, it’s essential you understand what this machine is and how it works. We’ll cover everything you need to know in this blog, including how to know if you need a dryer for your compressor. 

What are air dryers?

A compressed air dryer removes moisture from the air, which helps increase your air compressor’s longevity and efficiency. Air with a high moisture content can damage your compressor and the tools and equipment powered by your machine. Plus, many industries, particularly pharmaceutical and food, require clean and dry air, which is only possible when a dryer is used. 

How does an air dryer work?

There are several types of compressed air dryers, and they all work slightly differently. We’ll review how the four main types of air dryers work below.  

How do refrigerant air dryers work?

Refrigerating air dryers are one of the most common types and are commonly used in industrial applications. This is because they’re easy to maintain and are relatively cost-effective.

This type of dryer uses low temperatures to remove moisture from compressed air. Compressed air is rapidly cooled to approximately 3°C (the dew point)/. At this temperature, the water vapour in the air condenses into pure water, which can then be collected in a water trap. This condensation can be drained via discharge lines. The compressed air is then heated before powering tools, equipment or machinery.  

There are two types of refrigerant air dryers: cycling and non-cycling dryers. 

  • Cycling dryers can run continuously to maintain a constant dew point. 
  • Non-cycling dryers will turn off and on as necessary to maintain the required dew point.

How do adsorption air dryers work?

An adsorption or desiccant air dryer is commonly used as a second-stage dryer after the compressed air has already been dried (for example, by a refrigerant dryer). Adsorption dryers use a hygroscopic medium to dry the compressed air. This results in a significantly lower dew point (around -40°C.) and much drier air. 

There are two main types of adsorption air dryers: single-canister and twin-tower desiccant dryers. Single-tower desiccant dryers are less common and involve a single tower which contains a desiccant material to dry the air. They’re typically used for point-of-use applications because of their ease of use. 

In twin-tower desiccant dryers (sometimes called regenerative dryers), the compressed material passes through the desiccant material in the first canister and then through the medium in the second one. The second tower regenerates the desiccant material. This type of air dryer is suitable for industries and applications that require very dry air. 

How do deliquescent air dryers work?

Deliquescent dryers work very similarly to desiccant dryers. They’re commonly used in remote environments as no electricity is required to operate them.

Compressed air passes through a hygroscopic medium to remove moisture in a deliquescent dryer. Unlike desiccant dryers, deliquescent dryers use soluble salt tablets, which must be replaced regularly. Additionally, the dew point (the temperature of the dried air) will change depending on the temperature of the compressed air that enters the dryer. 

How do membrane air dryers work?

Membrane dryers are commonly used as second or even third-stage dryers, and like deliquescent dryers, the dew point will depend on the temperature of the air entering the dryer. They are common for dental or medical applications because they produce high-quality, super-dry air. 

A membrane air dryer uses a hygroscopic membrane to dry compressed air. The compressed air is forced through the membrane as the air pressure increases on one side of the membrane. The condensation is then carried away when a dry gas is run through the compressed air. 

Do I need an air dryer for my compressor?

If you’re unsure if you need an air dryer for your compressor, check if you experience any of the following problems with moisture in your compressed air system:

  • Pipelines rust and corrode. 
  • Air tools show water spots or damage.
  • Air tools’ exhausts spray out water vapour.
  • Water comes out of your compressor’s lines and/or hoses.

You’ll also need an air dryer if your equipment or tools require dry and clean air. 

How Air Supply can help

At Air Supply, we have decades of experience selling, servicing, and repairing a huge range of air compressors and compressed air equipment. We offer a range of high-quality air dryers, including adsorption air dryers and refrigerant air dryers, at competitive prices! Our team can help ensure your compressed air is dry and free from moisture to keep your machines working efficiently and effectively.

Our site offers one of the UK’s largest stocks of used air equipment and compressed air dryers. This is a great option if you’re on a limited budget or wish to try a dryer for your business. 

It’s easy to search and filter by the required features to find the perfect air dryer for your application. Air Supply also offers comprehensive maintenance, servicing, and repair services. So, if your dryer or compressor has any issues or is not performing as it should, you can rely on our expert technicians to get it up and running again!

If you’re still unsure if your business would benefit from a dryer, our friendly team will be happy to advise you. Get in touch with us today to find out more about our products and services, or speak to one of our compressed air experts about your compressed air needs. 


© Air Supply Ltd 1995 – 2024 | View our Cookie Policy | Company number: 4514029 | VAT number: GB929641690

Website createdfor Air Supply UK