The History of Air Purifiers

sterile air filters Air purification has been worked toward, to one degree or another, for over 200 years. The Industrial Revolution was a dramatic turning point in the history of mankind; unfortunately, it also introduced serious pollution to urban areas. Advancements in technology, as well as increasing awareness about the dangers of less obvious forms of pollution, eventually lead to the creation of modern air purifiers that so many homes and businesses rely on today.

HEPA (High Efficiency Particular Air) filters were developed by the US Atomic Energy Commission to filter out highly hazardous aerosols, toxic carcinogens, radioactive particles and biohazardous contaminates. This new technology (originally classified as top-secret) was capable of pulling 99.97% of impurities from the air, down to as small as 0.3 microns.

In 1963, US Congress passed the Clean Air Act to set standards for the reduction of air pollution through fuel emissions standards. This alerted scientists and consumers of the need to protect our lungs from pollutants such as perfumes, building materials, chemicals, pesticides, and allergens.

As more consumers became concerned about air pollution, HEPA air filters became popular in the 1970’s and 1980’s (and they were no longer classified as top-secret). However, at the time, they were bulky and difficult to operate. Today, air purifiers and sterile air filters are used in a variety of critical filtration applications in nuclear, electronic, aerospace, pharmaceutical and medical fields, as well as in homes around the world.

What is Compressed Air?

compressed air filtersCompressed air is a gas (or combination of gases) that has been put under greater pressure than the air found in a typical environment.  At it’s most basic level, compressed air is potential energy – very much like a compressed spring. It takes energy to compress a spring, and when that pressure is released, the potential energy stored in the compressed spring (or in this case, the air) is also released. That energy can then be used to produce “work”. Compressed air is often referred to as a production facility’s “fourth utility”, after electricity, water and gas.

As compressed air is expanded, it can be used directly as a motive force. There are numerous and diverse applications for compressed air, such as tire pumps, air rifles, aerosol cans, and even jackhammers. However, one cubic foot of compressed air can contain millions of dirt particles, considerable amounts of water and oil, and even heavy metals like lead and mercury. Therefore, the right compressed air preparation is essential.

At Greenleaf Filtration, you’ll find one of the most comprehensive ranges compressed air filters available today. Our filters can help trap dirt particles and other impurities that can prevent your air compressor from operating at peak performance. Liquid releases from the filter cartridge to an automatic drain just as rapidly as it enters the filter. They can also remove moisture from your environment, which provides better compressor air flow and improves air pressure for machinery maintenance jobs.

Filters for Liquid Processing

liquid bag filtersSelecting the right filters can minimize process downtime, reduce maintenance and waste disposal costs, limit worker exposure to the fluids, and improve product quality. However, proper filter selection can vary amongs industrial applications, including water filtration, boilers and irrigation. When it comes to liquid processing, consider these two basic filters:

Bag Filters
Liquid bag filters operate by capturing solids inside the filter media “bag”, and tend to be low cost. They generally have lower surface areas than comparable cartridge systems. Due to their wide range of process conditions, they’re a great choice for a variety of applications, including paints, water treatment, food processing, pharmaceutical, and more.

Cartridge Filters
Cartridge filters are used for removing suspended solids for applications with lower flow rates, where exposure to the process liquid is not an issue. They are typically the same initial cost as bag filters, but contain a higher operational cost.

If operator and environmental exposure to the liquid is acceptable, and loss solids must be removed, both bag filters and cartridge filters are recommended. When selecting a filter for liquid processing, it’s important to ultimately consider the cost, flow requirements, and operator exposure risks.

Air Quality and the Pharmaceutical Industry

sterile air filtersEach facility has unique needs when it comes to air compression; and it’s not surprising that compressed air is held to a very high standard in the pharmaceutical industry, where cleanliness is especially critical. As the pharmaceutical industry has grown, also has its utilization of compressed air for breathing air, operation of equipment and instrument air. The primary challenges to air quality in this industry are:
Oil contamination found in compressed air originat
es from oil particles present in the immediate environment, as well as compressor fluids and lubricants. Other contributors are vehicle exhaust and industrial activity. Using oil-free compressors can limit this type of pollution.

Moisture is another common contaminant, and can be harmful as it provides a breeding ground for bacteria. Moisture can also react with certain materials causing corrosion or rust, thus causing damage. In this case, coalescing filters should be used to remove water aerosols and liquid water.

Solid Particulates
Solid particulates can also pose a threat to the quality of compressed air. Dirt, pollen and other fine particles in the environment can build up in an air compressor and cause obstructions, negatively affecting performance.

Considering the wide range of uses for compressed air and sterile air filters in the pharmaceutical industry, it can be difficult to establish a standard. To determine the best equipment for your particular facility, contact an expert at Greenleaf Filtration.

Why You Need Condensate Drains

condendate drainsThere are many users of compressed air systems that don’t fully recognize the possible implications of disregarding condensate drains. Although compressed air condensate is typically just condensed water, it can also include some oil and contaminants, which can be harmful to your equipment. To avoid costly and unnecessary maintenance and help ensure the desired productivity of your system, there’s no doubt you’ll need to use condensate drains on your system components. This will ensure the contaminants are removed from your system, thus increasing the life expectancy of your equipment.

Condensates are produced when the compressed air in your system cools. This contaminated moisture is likely to be found within your piping and storage vessels. When it builds up over time, the accumulation can cause a range of problems such as poor system efficiency and excessive wear of associated equipment.

Although condensate drains are one of the most ignored components of a compressed air system, they are essential for system efficiency and reliability. This is because condensates are inevitable, regardless of what type of system you’re using or the conditions of the environment in which it’s located. However, products are available to lessen further accumulation. At Greenleaf Filtration, we offer a wide selection of the industrial process filters and condensate drains you need to meet your special requirements.

The Importance of Lubricating Your Air Compressor

industrial filtration solutionsHave you been noticing a difference in the operation or performance level of your plant’s air compressor? Is it running at a slower rate, or does it occasionally shut down altogether? While your first assumption may be that it’s time to invest in a new machine, it’s important to first recall if you’ve done any preventative maintenance recently. Industrial machines require proper preventative care, and air compressors are no exception. Air compressor filters need to be changed regularly, and it’s also crucial to properly lubricate your air compressor. Here’s why:

Keeping it Cool
Lubricants are required to keep your air compressors running at a cool temperature. If your machine instead maintains a high temperature, its internal components will wear down over time. This will lead to more money spent on industrial filtration solutions than what’s necessary.

Consuming Less Energy

An air compressor is guaranteed to last longer and run smoother when it consumes less energy at a time. When an air compressor is running hot, it is also working harder, which causes it to consume more energy as it operates. By keeping your air compressor well-lubricated, you’ll both save energy and avoid potential repair costs.

Increasing Life Expectancy
If your air compressor is operating efficiently with the help of proper lubrication, it will require less maintenance and last longer – thus saving you money.

Why You Need to Change Your Plant’s HVAC Air Filters Regularly

industrial filter supplier in RichmondAs an industrial plant manager, even though you’re dealing with heavy machinery and lots of raw productive power, you know that your plant is actually a pretty delicate operation. If the slightest thing goes wrong, you could end up losing out on precious hours, or even days, of operating time – which could translate into big revenue losses.

A plant is only as strong as its weakest link, and if you haven’t made the time to get your air filters checked out recently, there’s a good chance that your weakest link is about to snap.

Protect Against Internal Pollution
If it’s been a while since you’ve replaced your plant’s air filters, you need to get in touch with an industrial filter supplier in Richmond today. Your air filters don’t get nearly the attention they deserve, since they need to be able to process and filter thousands of cubic feet of air every single day.

After a while, your air filter will start to get full of pollutants, and it won’t be able to do its job effectively. This means that all of the impurities that are in your air, including industrial pollutants, chemicals, dust and debris, and even mold spores, will go right past your filter and can be inhaled.

Keep Your Air System Safe and Efficient
A dirty air filter doesn’t just expose you and your team to harmful pollutants; it also makes your HVAC system have to go into overdrive just to move air through the ducts. This means that you’ll end up literally wasting money on heating and cooling, simply because the system isn’t operating at a high degree of efficiency.

In the high-pressure business climate of today, you simply can’t afford to float any useless expenses; therefore, it’s imperative that you ensure your air filters are in good shape.

How to Protect Your Plant from Internal Pollution

industrial air filtration systemWhen you’re in charge of managing an industrial plant, you should know the importance of maintaining high safety standards. Following proper safety protocols not only keeps you and your team safe, but it prevents the loss of revenue created by work stoppages due to accidents.

While you probably make sure to adhere to major safety standards with regards to your machinery and your personnel, you probably overlook the safety of your HVAC air systems. This is understandable, as lapses in air filtration maintenance usually don’t create the kind of high-level emergencies as other safety lapses.

However, if you’re not paying attention to the possibility of internal pollution in your plant, you could be setting yourself up for some major losses down the line.

Air Filtration Maintenance
In order to make sure that your plant is operating with the highest safety standards, you need to pay serious attention to your industrial air filtration system. When your air filtration system is working properly, it’ll remove pollutants from the air and keep a good air circulation going inside your industrial plant.

However, in order for your filtration system to function this way, you need to make sure that you get your filters changed regularly, and that your whole HVAC system is checked and cleaned annually.

Keep Your Air Clean
A dirty air filtration system can create internal pollution by allowing chemical pollutants, dust, molds, and other impurities to cycle and recycle into your plant’s air. Over time, these pollutants can compound, causing pollution to severely worsen.

This can have serious health impacts on you and your team, and could even open you up to legal liability if one of your employees becomes ill or injured. Make sure you’re avoiding internal pollution by checking your air system regularly.


by Jessica Exley, Donaldson Process Filtration
Food and beverage processors in the United States and abroad
operate under some of the most stringent standards relating
to food safety. The Food and Drug Administration (FDA),
International Featured Standards (IFS), Safe Quality Foods (SQF),
British Retail Consortium (BRC), and 3-A Sanitary Standards, Inc.
(3-A), respectively, all set forth standards that must be met at the
risk of production shut down.
Two areas of increased evaluation are the use of sterile
compressed air and culinary steam in the food processing
industry. While the language surrounding the various standards
differs slightly, from “unlawful indirect food additives” to
“monitored for purity,” it is—at its core—about protecting
manufacturers and consumers.
Understanding and navigating industry standards means
understanding the roles of sterile compressed air and culinary
steam in the industry and your facility.
Sterile compressed air is an indispensable part of the
food manufacturing process, because it is used for mixing
ingredients, storing products under positive pressure (to prevent
the ingress of contaminants), pumping viscous products through
pipelines, bagging or packing products, rejecting sub-standard
products from conveyors, and blowing food and other debris off
work surfaces and production equipment.
Unfiltered compressed air contains particulates, oil and water
aerosols, and bacteria. These undesirable contaminants must
be removed from the manufacturing process in order to ensure
product safety and consistency. So, what can be done to filter
compressed air?
Years of engineering and testing have shown that a three-stage
filtration system is ideal for producing sterile compressed air on
demand at the various points-of-use. The three-stage system is
able to provide the sterile-level removal efficiencies required in
the industry while minimizing the change out frequency of the
more expensive sterile filter. (See Illustration A.)
Filter #1 should be composed of relatively open or “loose” media. This configuration allows for the removal
of large amounts of water and rust that typically contaminates the lines after refrigerated drying equipment.
The open media prevents the filter from becoming blocked too quickly. Higher-end filters will use a binderfree
fibrous media that is both hydrophobic and oleophobic. This allows the filter to quickly shed water and
produce high flow rates at a lower pressure loss, minimizing energy consumption.
Filter #2 should remove all remaining water and oil aerosols as well as any particles that may have
penetrated the first filter. Because the second filter needs to have greater capture efficiency than the first
filter, the ideal filter should incorporate a pleated media structure. A pleated structure produces greater
media surface area, which reduces the pressure loss and increases service life by providing more dirt
holding area than non-pleated media.
Filter #3 is designed to capture microorganisms and reliably withstand the extreme conditions of steam
sterilization. Filtration media made of PTFE membrane or borosilicate is often the best choice because it is
highly resistant to steam and can be very tightly controlled to produce a bacterial-retentive structure that
remains effective over the entire service life. Since this filter should not encounter any dirt or oil, choose a
version that can tolerate a high number of sterilization cycles. This filter should be rated at >99.9999998% at
0.2 micrometers because this is the size of some of the smallest bacteria. This is also the approximate size
that corresponds to the lowest-efficiency point of most depth filters.
Illustration A. Recommended Compressed Air Filtration
In the food-processing industry, culinary steam is direct injected into food for cooking or used indirectly
to clean and sterilize vats, mixers, conveyors, and other equipment used in the food-production process.
Culinary steam is defined by 3-A Accepted Practice 609-03 as “steam that is free of entrained contaminants…
and is suitable for use in direct contact with food products, other comestibles, and product-contact
The primary safety concern is that un-filtered steam can contain contaminants including rust and dirt
that could end up in the food product. Unfortunately, a major source of contamination is often the steamgeneration
process itself, especially in systems where excess steam is condensed, recirculated, and reused
in the process. This “recirculated condensate” can be contaminated with pipe scale and suspended solids,
as well as oils and metallic debris shed by the pumps in the recirculating system. If the steam is not filtered
before use, these contaminants can make their way into the food product. So, what can be done to generate
culinary steam?
There are two critical stages of a culinary steam filtration system: a final culinary steam filter in addition to
a pre-filter or entrainment separator. (See Illustration B.) Point-of-use filter housings designed with stainless
steel, free from imperfections such as pits and crevices, is ideal for producing culinary steam. Culinary steam
filtration should be installed at all points-of-use because any piping downstream of your final filter could
create additional opportunities for contaminants to enter the system.
Filter #1, often referred to as the steam pre-filter or an entrainment separator, should effectively remove all
particulates 10 μm in size or larger from the production line’s incoming steam source.
Filter #2, identified as the point-of-use culinary steam filter, should remove 95% of particulates 2 μm in size
and larger.

Additionally, filtering your culinary steam will significantly reduce your plant maintenance costs. Unfiltered
steam can coat heat exchangers producing an undesirable insulating effect which can slow heat transfer and
increase production times. The proper filtration system will also remove dirt, rush and scale that can abrade
pumps, valves and other hardware causing premature equipment failure.
As interest over consumer and product safety standards continue to grow, food and beverage manufacturers
around the globe can expect increased attention on the food safety standards and processes within each
facility. Protecting your customers—and your business—by verifying that your production processes are in
compliance with current regulations will help mitigate those concerns.
If you’re not sure whether your current sterile compressed air or culinary steam filtration system meets the
latest standards, contact a filtration consultant specialized in serving food and beverage processors


Jessica Exley is a member of 3-A Sanitary Standards, Inc. and Director of Process Filtration at Donaldson Company


Water/Particulate Breathers

Water/Particulate Breathers

The Eaton tank breather filters “breathe” air in and out as the oil level rises and falls. The filters prevent the penetration of contamination from the ambient air in the hydraulic fluid. This circulating air contains articles and moisture that can cause corrosion, increase equipment wear, and reduce fluid performance. In typical systems, the internal hydraulic fluid is warmer than the external environment. This difference in temperatures causes water vapor to form. Breathers protect your hydraulic system by filtering out damaging moisture and particles.
Contact Greenleaf Filtration for Eaton Breathers. Toll Free (888) 974-6171