Saving costs with compressed air

Looking for ways to reduce your compressed air costs? You will find them right here.
energy cost savings graphic

10 steps to a green and more efficient production

Carbon reduction for green production - all you need to know
10 steps to green compressed air production

Everything you need to know about your pneumatic conveying process

Discover how you can create a more efficient pneumatic conveying process.
3D images of blowers in cement plant
Close

The right inline air compressor filter solution

Air Treatment Installing an Air Compressor Compressed Air Wiki Contaminants in Compressed Air Micro-organisms in compressed air Filtering Oil in compressed air How To Condensate in compressed air

Choosing an inline air compressor filter isn't overly complicated. However, it's important to have a basic understanding of the filtration process. This article walks you through the fundamentals of how this component works within your compressed air system.

Why do you need an inline air compressor filter?

Choosing a filter to dry compressed air

As pointed out in past articles, compressed air is full of particles, aerosols and oil vapors.

This contamination can cause potential harm to end users. Incorporating the correct inline air compressor filter helps eliminate unwanted particulates as well as aerosols and vapors.

The amount and types of filters needed depends on the quality of air your application process requires. Let’s take a look at different types of filters and the questions that will help you choose the correct filter.

What is the optimal air quality?

Air quality icon

Not all applications and processes utilizing compressed air require the same level of filtration. To understand the appropriate air quality for your application, you'll need to evaluate your compressed quality requirements, your air process and flow.

A standard dry particulate filter providing filtration down to 1 to 0.01 micron is generally used for pneumatic purposes. However, if your process requires OSHA approval and elimination of oil vapors, then a charcoal filter is necessary.

With this, it's useful to understand three key contaminants found in compressed air, particulates, aerosols, and vapors. These can originate from ambient air, as well as the air system.

Compressed air contaminants

Particulates: Particulates in compressed air are small pieces of material like dust, dirt, and/or pollen, as well as loose metal pieces. Depending on the sensitivity of your application and or process, contact with particles can be damaging to the end product. They can also cause delays in production and quality control issues, as well as unsatisfied customers.

Aerosols: Aerosols consist of small droplets of liquid found within a compressed air system, especially in oil-injected machines. Aerosols are created from lubricant. Therefore, oil used in the compressor can be harmful to both products and people if not treated properly.

Vapors: In a compressed air system, vapors consist of lubricants as well as any other liquid that has converted to a gas. Such vapors require a special carbon activated filter in order to be removed from the system.

Now that we have a better understanding of the contaminants above, let us take a look at what types of filtration methods are used.

To find out more about our filter media and filtration innovations, check out this video.

Removing dry particulates

There are three main mechanisms utilized in dry particulate filters to remove solid particles from compressed air. These three forces contribute to the overall efficiency of the filter.

Inertial Impaction: Inertial impaction is a process where particles that are too heavy to flow with the compressed air stream get trapped in the fiber media of compressed air. The larger the particles are, the easier it will be to separate them.

Interception: Smaller particles can follow the air stream. However, if the diameter of a particle is larger than the gap of the filter media, it will get caught by the filter media. This makes it easier to eliminate larger particles than smaller ones.

Diffusion: Diffusion happens when small particles move erratically throughout the surface, instead of following the compressed air stream. This irregular movement path is caused by the particles colliding with other gas particles, an occurrence called Brownian movement. Since the particles have a free-range of motion, it is more likely that they become intercepted and removed by the filter media. Through diffusion, separation of smaller particles is easier than separating larger ones. 

Removing aerosols and vapors

Two types of filters are used to remove aerosols and vapor. Coalescing filters are utilized to remove liquids as well as some particulates, while vapor filters use adsorption to remove vapors from compressed air.

Coalescing: Coalescing filters are used to remove aerosols and particulates, but are not effective in the removal of vapors. The coalescing process consists of bringing small droplets of liquid together in order to form large droplets. As the droplets increase in size, they fall from the filter into a moisture trap, resulting in a cleaner and dryer compressed air stream.

Adsorption: Adsorption is a chemical process used to remove gaseous lubricants or vapors. This process involves vapors bonding with the surface of the media (adsorbent). Activated charcoal filters are commonly used since they attract oil vapor.

As the oil vapor covers the surface of the activated charcoal over time, it is essential to change the filter before it becomes saturated. If not, this would lead to a breakthrough of the oil into the air system.

It is also necessary to use a dust filter after the activated charcoal filter. This is because small charcoal particles could break out and enter the air stream.

Can lubricants like oil cause damage?

To assess the potential damage oil can cause to your compressed air system, it's important to understand your equipment and basic industry requirements. If your industry has strict health codes and or your equipment is sensitive to oil / vapor exposure, it is crucial to use proper filtration.

Let’s take a closer look at lubricants and understand the effects they can have on your end product. Similar to particulates, lubricants can enter your compressed air system from ambient air as well as from the compressor itself. Facility operations, like a motor exhaust, release hydrocarbons like oil aerosols into the ambient air, which can compromise air quality and cause equipment failure.

Oil injected air compressors will also release lubricants into the compressed air system, resulting in increased operational and maintenance costs. Industries such as electronics and semiconductor are especially exposed to lubricant contamination, which can result in product loss, missed deadlines and unsatisfied customers.

Proper filtration

Poor filtration usually causes pipe corrosion, increased pressure drops and can cause equipment damage, resulting in costly downtime and unexpected repair costs. Corrosion can also cause excess debris in your piping system, which in turn results in your compressor working harder. This leads to higher energy consumption and excess wear on compressor parts.

Proper filtration is key in achieving desired results when strict codes or purity classes are enforced. The only way to fully protect your product from unwanted oil in your compressed air system is to utilize oil-free compressors. This type of technology eliminates the risk of contamination, resulting in clean, high quality compressed air.

In this guide you will learn everything you need to know on air treatment. From different types of contaminants to knowing your air quality requirements; this guide covers all important air treatment topics.

Do you have any specific questions for us or do you need more support? Our air treatment experts are happy to help you. Get in contact by clicking the button below.

Related articles

an illustration about air treatment for the atlas copco wiki pages

How to Remove Contaminants from Compressed Air?

27 September, 2022

A number of decisions must be made when installing a compressed air system for it to provide the right air quality. Let us take a look at how to remove harmful contaminants, like water vapor and oil, from the output air.