Tag: intake air

Air Quality Classes: ISO 8573-1

Published on by John BallLeave a comment

Airborne particles surround us everywhere.   In a general work environment, nearly four million particles per cubic foot are floating around us at any given time.  When an air compressor brings in this air, the concentration increases substantially.  So, compressed air is not only expensive to make, but very dirty.  As the air exits your air compressor and travels into your pneumatic system, there is so much contamination, that the International Standard Organization, ISO, created an Air Quality chart with Purity Classes.

This chart is easy to follow and can be found on the International Organization for Standardization; ISO 8573-1 for Air Quality.  It is used to select a cleanliness level for your compressed air system. Contamination is categorized into three areas; Particles, Water, and Oil (reference above).  Each class is associated with a number for each category ranging from 0 (most stringent) to 9 (most relaxed).  As an example, the Air Quality value of ISO 8573-1:2010 [1.2.4] has Class 1 for Particles, Class 2 for Water, and Class 4 for Oil.  These class values will show the maximum value in each category.

To define the categories in more detail, I will separate the three to discuss the origins and solutions.

Per the descriptions above, here are the criteria by which compressed air purity is classified.

Particles: For solid particles, this part comes from many different areas.  The surrounding ambient air that is being drawn into the air compressor is filtered, but the intake filter will only remove large diameter particles.  The smaller diameter particles will go through the filter and into the compressed air system.  Another part is rust particles that come from steel air pipes and receiver tanks.  Over time, rust will flake off and create particles that can affect pneumatic equipment.  Other particles can come from components inside the air compressor, valves, etc., that wear and breakdown.  In the ISO column for Particles, it is separated into three different micron ranges and concentrations.  The removal of particles from the compressed air is done by traps and compressed air filters.  EXAIR offers two types; Filter Separators with 5-micron filtration and Oil Removal Filters with 0.03-micron filtration.  There are other types of filtration systems depending on your ISO requirement.

Water:  Humidity is a natural occurrence.  It can be measured as a dew point temperature.  This is the temperature at which water will condense and make rain.  Inside an air compressor, the air is ‘squeezed”, and the amount of space for water vapor is reduced.  So, it will condense into liquid form as “rain” inside the pipes.  Air that comes out from an air compressor will always be saturated with water.  To remove liquid water, a mechanical device can be used.  Inside a Filter Separator, a centrifugal separator will spin the air and remove the liquid water.  To remove water vapor, a compressed air dryer is required, like a refrigerant, desiccant, deliquescent, or membrane type.  Each type will have a maximum dew point range that they can reach.  As an example, a refrigerant type will reduce the dew point to 37oF (3oC).  That means that water will not condense until the temperature reaches below 37oF (3oC).

Oil: This category can be found as a liquid, aerosol or vapor, and it includes more than just oil. It contains small hydrocarbons like CO, CO2, SO2, and NOX.  Oil mainly comes from inside an oil-flooded air compressor.  As the air passes through the compressor, it will pick up remnants of oil aerosols and carry them downstream.  With high temperatures inside the air compressor, some of the oil will vaporize.  Even with oil-less type air compressors, carbon vapor can still be an issue.  Small hydrocarbons can come through the air intake and condense inside the system like water vapor above.  To remove the liquid and aerosol type of oil, Oil Removal Filters can be used.  They are designed to “coalesce” the small particles into larger particles for gravity to remove.  Oil vapor requires activated carbon to remove it.  These types of filter units will adsorb the vapor.  This helps to remove odors as well as dangerous chemical vapors that may be in the compressed air line.

There are a variety of pneumatic systems that use the ISO 8573-1 standard.  This will include breathing air operations, food and beverage, pharmaceutical, and the electronics industry.  If you need stringent requirements for your compressed air system, the Air Quality standard should be used by referring to the class numbers above.  This helps to dictate the types of filtration and air dryers that should be used within your pneumatic system.  If you have any questions about your compressed air system, an Application Engineer at EXAIR will be happy to help you.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Take It All In – Just Filter It

Published on by Brian FarnoLeave a comment
The Nose – Only the Nose Knows

Take a nice deep breath as you read this. In through the nose. If you are like me right now, due to Fall allergies you’ll have a little bit of a restriction, hold it for just a second and then breathe out through the mouth. The body is an amazing thing, when we breathe in through our nose the body has some natural filtration built in that is also known as nose hair. While not the most attractive thing to most, it is important. The hairs in the nose help to filter out allergens and catch foreign debris.

An Improperly maintained Cabin Air Filter on a car makes a great bed for mice

Other items you interact with daily have similar air intake filtration. A car often has both an intake air filter and even an in-cabin air filter, these both protect various parts. The engine air filter is vital to prevent dust, debris and even excessive water from entering into the precision machined and assembled motor. The HVAC system in every business or home generally has an intake air filter in order to protect the coils and heater box.

There’s another system in most manufacturing facilities that should always have a filter on it, and that is the compressed air system. Properly maintaining and filtering the incoming ambient air feed before it is compressed starts the process of on the right foot to optimize performance and insure efficiency is maintained from the start of the entire process. These filters are like many others and can be part of a preventative maintenance program. The air compressor manufacturer will have a recommendation on frequency for the various types.

Old Piston driven air compressor intake air filter.

If these filters are left unchanged then the compressor begins to have restricted flow on the intake which then results in less air being pulled in or maybe the filter is removed and then the debris all gets pulled in and sent through to become foreign debris inside the compressor. Both of these will cause the compressor to wear or overheat and work harder to compress the air and send it into the storage tank. This results in premature maintenance needed on the compressors and or point of use devices.

Thus, always filter your incoming air. Whether for your air compressor, car engine, or house, start with a fresh intake and then keep it optimized from there. The payback will be longer lasting equipment that operates at a higher efficiency. And remember, breathe in through your nose.

If you would like to discuss your filtration setups, feel free to reach out to an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF