Everything You Need To Know To Find The Best inline compressed air filter

Inline compressed air filters are vital for having clean air for your applications and pneumatic tools. However, it can be difficult when trying to decide. Understanding the contaminants in your air supply and which filter types can remove them is the first step in selecting the right inline air filter for your system.

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In this article, we'll answer the following questions:

1. How Does Compressed Air Become Contaminated?
   
2. What are Inline Air Filters Used to Remove?
   
3. How do Inline Air Filters Work?
4. What is Considered Optimal Air Quality?
   
5. Choosing the Right Inline Compressed Air Filter Setup for Your System

How does Compressed air become contaminated?

A poor air supply can be caused by multiple sources. For example, compressed air can become contaminated from dirty ambient air, humidity, oils leaking from the air compressor, corroded air lines, and even from the air filter itself. Understanding the contaminants and their origin is a good starting point for shops experiencing poor air.

The majority of the contaminants found in an air system are:

• Liquid water
• Water vapor (humidity)
• Oils
• Oil vapor
• Dust
• Dirt
• Aerosols

The dust and tiny particles in the ambient air around you are the same contaminants that can enter your system while it is running. Contaminants are different-sized microns and can cause varying kinds of damage depending on their form.

Compressed air can also become contaminated from oils within the air compressor, corroded air pipes, and poorly maintained air filters.

Compressed air filters pull out the bulky contaminants - like dust particles, particulates, oils, and liquid water - to prevent equipment damage and maintain air system performance.

What are inline air filters used to remove?

Inline air filters for air compressors effectively remove liquid water, oils, oil vapors, dust, dirt, aerosols and other bulky particulates. There are three types of air filters designed to remove certain contaminants:

1. Water separators
2. Oil Coalescing filters
3. Activated Carbon Filters

1. Water Separators

Water separators are designed to remove large particulates and liquid water.

2. Oil Coalescing filters

Oil coalescing filters pull out oil vapors, small and fine particulates, and bulk oils from the air stream.

3. Activated Carbon filters

Activated carbon filters eliminate odors, tastes, and remove aerosols from the air flow.

How do inline Air filters work?

Each of the three filters - oil coalescing, water separators, and activated carbon - are designed to target specific kinds of contaminants. To get the clean, dry air needed for your application it may require one, two, or even three air filters. This is dependent on which contaminants should be filtered out for your system to work the way it's intended.

These filters work by removing contaminants at a specific micron size: microns are particles that cannot be seen by the human eye. Depending on the amount of air filters installed on a system, the contaminants of different micron sizes filtered out can help the air become clean and dry, or just clean. There are ISO regulations that detail the class, particle sizes, and the pressure they can withstand. This is important to refer to when choosing the right compressed air filter for you.

What is considered optimal air quality?

Air quality requirements are different for every system. There isn't a one-size-fits-all solution when it comes to filtration for equipment - air quality requirements are different for every system. The way to find the filtration required for your air compressor system, is by reading the fine print on the machine and consider the application it is being used for.

There's also a set of standard ISO -05 regulations required for some industries.

It's important to know the filtration needed for specific air systems so they operate at their highest efficiency and do not dysfunction prematurely from not having the right inline air filter.

Download our air system schematic to understand how each air filter pulls out contaminants and how they pair with the most common air dryers.

 

choosing the right Inline Compressed Air Filter setup for your system

There are a few considerations to make before purchasing an inline compressed air filter package:

1. The specific air requirements for your machine or application
2. The ISO requirements of your system or industry
3. The desired outcome of the product or process
4. Other air treatments in place, such as drains, dryers and other filters

We recommend some initial investigation of your compressed air needs and cleanliness goals. Here's a guided checklist to get started on selecting the right inline compressed air filter:

• Refer to the list above to determine the air cleanliness goals and needs for your system.
• From there, determine the air demand of your system (10 CFM, 25 CFM , 50 CFM etc..) so the filters can be sized properly. Note: Purchasing larger filters does not mean cleaner air, they will only add cost to your operations.
• Finally, make sure to choose an air filter that is of higher quality and fits your maintenance schedule. Investing in cheaper products will only add headaches to your operations as they need to be replaced more often.

Ensuring Optimal Performance with the Right Inline Compressed Air Filter

Selecting the right inline compressed air filter is a crucial step towards ensuring the efficiency and longevity of your pneumatic tools and applications. As we've explored, understanding the variety of contaminants in your air supply and the specific requirements of your system is fundamental. Inline air filters, ranging from water separators to oil coalescing filters and activated carbon filters, each play a distinct role in purifying your air supply.

Remember, the key to achieving optimal air quality lies not just in selecting the right filter type, but also in considering factors such as your system's specific air requirements, ISO standards, and the desired outcome of your product or process. It's not a one-size-fits-all situation; each system requires a unique combination of filters to meet its specific needs.

In conclusion, we recommend conducting a thorough assessment of your compressed air needs and cleanliness goals, followed by consulting with a compressed air professional. This approach ensures that you invest in a high-quality, appropriately sized filter setup that aligns with your maintenance schedule, leading to enhanced system performance and reduced operational costs.

Not all compressed air is created equal. Neither are all compressed air systems.

Your compressed air needs to provide the flow, pressure and level of air quality required by your processes. A well-designed compressed air system supplies that air as economically as possible. A poorly designed system misses one or more of those goals.

So what makes a well-designed air compression system?

• An air compressor provides the flow and pressure.
• A compressed air dryer improves air quality by removing moisture.
• Compressed air filters improve air quality by not only removing some moisture but also other contaminants.

What is air quality?

Air quality is a measure of how few contaminants are in the air stream. As mentioned above, compressed air dryers can help remove one type of contaminant'moisture. But filtration is needed to remove other types of contaminants from your air lines.

Types of contaminants removed by filtration

Particulates

Particulates are typically solid particles (e.g. dry and wet dust, pollen, and rust from pipe corrosion) and large liquid drops.

For more information, please visit hydraulic driven air compressors.

Aerosols

Aerosols include both oil aerosols and smaller droplets of water.

Vapor

Vapor consists primarily of oil and other hydrocarbons in a gaseous form.

Levels of compressed air filtration

The air quality level for all compressed air applications can be defined by the air quality classes in the ISO -1: standard. (See the post The ABC's and 1-2-3s of Air Quality Classes for details about air quality levels and classes.) This standard specifies the allowed levels of contamination for each contaminant type at each air quality class. To meet these levels, you need to use the right types of air filters with the right degrees of filtration.

Types of compressed air filters

Particulate filters

Particulate filters remove particulates from the air stream by trapping contaminants on the media. The filter element design and material determine the size of the particles it can trap, so particulate filters have varying degrees of filtration.

Coalescing filters

Coalescing filters remove water and aerosols of liquids like oil by coalescence. Coalescence is the process of trapping smaller droplets along the media until they combine into larger drops that fall out of the air flow. The structure and type of media determine how much aerosol can be removed, so they also have varying degrees of filtration.

Combo particulate/coalescing filters

Some filter designs (e.g., Sullair SX series threaded and flange filters) act as both particulate and coalescing filters. You only need one filter with a single element to handle both types of filtration.

Activated carbon

Activated carbon filters are used to remove oil and hydrocarbon vapors from compressed air and reduce oil carryover to .003 mg/m³. These filters are most typically used where removing taste or odors is critical, e.g. food processing and pharmaceuticals.

Degrees of filtration for particulate and coalescing filters

Coarse

Coarse particulate filters can only remove large particles from the air stream.

• Depending on filter materials and design, the smallest particles they can remove will be anywhere from 5 to 40 microns.
• Coarse coalescing filters can reduce oil carryover to as little as 5 mg/m³.

In most cases, coarse filters don't provide high quality air. However, they can help remove moisture and keep large particles from fouling compressed air tools and instruments. (Unless those tools or instruments require higher quality air, of course.)

Fine

Typically, fine filters are the minimum size needed where applications or equipment need high quality air.

• Fine particulate filters can remove particles as small as 1 micron.
• Fine coalescing filters can limit oil carryover to .1 mg/m³.

Superfine/micro

Superfine filters are used when the highest quality air is needed; for example, for food production, pharmaceuticals, spray painting, and instrumentation.

• Superfine (sometimes called micro) particulate filters can remove particles as small as .01 micron.
• Superfine coalescing filters can limit oil carryover to .01 mg/m³.

Why not just use a single superfine filter? Or an active carbon one?

All degrees of filtration can collect larger particles and aerosols than they are optimized for. That might tempt you to just use filters with the highest degree of filtration needed'but you shouldn't.

When filtering larger contaminants with finer filters, the buildup and loss of efficiency can happen much more quickly. (An active carbon filter could become clogged in hours, for example.) This can lead to unnecessary costs for replacement elements.

When should I replace my filter elements?

All filter elements have a maximum usable saturation point and eventually need replacing. Over time, contaminants build up on filter elements (including coalescing filters, as some solid particles, however small, are always present). Eventually, this buildup reduces the efficiency of the element. This efficiency loss causes larger pressure drops and allows more contaminants to pass through.

You shouldn't try to save money by delaying or not replacing elements. If you don't replace filter elements once they reached their maximum useable saturation point, your overall production costs could increase in three ways:

• Increased energy costs by requiring your compressor to run at a higher pressure set point.
• Increased production costs caused by additional contaminants ruining finished goods
• Increased equipment capital and/or maintenance costs by additional contaminants damaging equipment

Typical filtration in compressed air systems

These typical filtration examples for compressed air systems assume combo particulate/coalescing filters unless otherwise noted.

System without dryers

In systems without dryers, install a coarse or fine filter immediately after the compressor.

• Use a coarse filter if it meets both your particulate and aerosol requirements per ISO -1:.
  • Even if your processes don't need to reach a particular ISO class, installing a coarse filter to remove excess particulates and oil can help protect your air tools.
• Use a fine filter if the coarse filter doesn't meet both requirements.

If you need a stricter level of filtration, add a superfine filter after the fine filter.

Systems using refrigerated dryers

In systems using a refrigerated dryer, install a fine filter between the compressor and the dryer.

If you need a stricter level of filtration, install a superfine filter after the dryer.

If an active carbon filter is needed, install it after the superfine filter.

Systems using desiccant dryers

In systems using a desiccant dryer, install a fine filter between the compressor and the dryer.

If you need a stricter level of filtration, install a superfine filter between the fine filter and the dryer.

• You should consider installing the superfine filter even if you don't need to meet a superfine filtration level. By removing more contaminants before the air reaches the desiccant bed, you can extend the life of the desiccant.

Immediately after the dryer, you should install a fine particulate filter (e.g. the Sullair SX, FXFRHT and FWFRHT particulate series filters) to remove any dust coming off the desiccant bed.

• You could install a combo filter instead, but no additional aerosols will be added by the desiccant bed. Therefore, a combo element would add an unnecessary expense.

If an active carbon filter is needed, install it after the fine particulate filter.

But how much filtration does my system need?

While typical filtration arrangements can serve as guidelines, your filtration should always be designed for your process needs. Too little filtration and the air stream could contain too many contaminants to provide the correct quality of air. Too much filtration and you could be paying more for your compressed air system and its upkeep than you need to.