Filtration

The high transmission rate of coronavirus (COVID-19) has prompted the Center for Disease Control and Prevention (CDC) to recommend that everyone in the U.S. wear nonsurgical face masks when going out in public because people infected with the virus may emit aerosols (particulates or microorganisms) when they talk or breathe. These infectious viral particles can float or drift around in the air. This has raised concerns about indoor air quality and the potential for airborne transmission through an HVAC system. Therefore, in many industries from healthcare to manufacturing, facilities managers are exploring whether their buildings are equipped to reduce the threat of infection. 

To help our customers gain a better understanding of HVAC filtration as it relates to COVID-19 and other airborne transmissions, our filtration experts have compiled a list of frequently asked questions. 

 

 

For the full list of frequently asked questions on HVAC filtration as it relates to COVID-19, download the FAQ Fact Sheet.

 

Can the coronavirus or other illnesses spread through an HVAC system?

The spread of the novel coronavirus (COVID-19) mainly occurs through respiratory droplet transfer from person-to-person within a close range of about six feet according to the CDC. The virus can also be transmitted on objects and surfaces that a contagious person may cough on, sneeze on, or touch. Pathogens can also travel on dust and dirt particles as those particles move through the air. Therefore, the potential for airborne transmission through an HVAC system exists.

 

Can HVAC filters protect people against the coronavirus (COVID-19)?

HVAC filters can reduce but not eliminate the threat of infection. The coronavirus and the particulate it travels on is very small in size, and can range from submicron (less than 1.0 micron in size) and larger. High-efficiency filters on the market today can trap particulate sizes that are likely to remain in the air. Selecting the right filter can reduce risk while improving the quality of indoor air.

 

What type of air filter do you recommend for reducing the spread of coronavirus (COVID-19)?

When selecting a filter to combat the threat of airborne transmission, you have to consider the level of filtration wanted versus effective system operation. HEPA and ULPA filters provide the highest rate of effectiveness, but many HVAC systems would not be able to use them without extensive retrofit. We suggest a minimum efficiency reporting value (MERV) rating of 14 to 16 for most HVAC systems. Sub-HEPA, HEPA and ULPA filters can be used where needed and for systems which can use them effectively. Where systems cannot accommodate higher efficiency filters, MERV 13 filters can provide significant improvement in efficiency and can be easily installed in the majority of HVAC and residential units. There are several filters in Parker’s line that can be used as part of an overall comprehensive strategy. We can assist you to determine which filter or filters would be the best choice for your application.

 

Can you give me some instructions on where to install an air filter in a commercial building to keep employees and occupants safe from the coronavirus?

Our best recommendation is to visit the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) website. ASHRAE has developed proactive guidance for building industry professionals to help address the ongoing concerns of the coronavirus (COVID-19) outbreak. There you can access the latest response resources from ASHRAE and other leading organizations with respect to the operation and maintenance of HVAC systems.

 

What is a MERV rating for an air filter?

MERV stands for “minimum efficiency reporting value.” It’s a rating system that was developed by the American Society of Heating, Refrigeration and Air Conditioning Engineers (or ASHRAE). MERV values range from 1 to 16. The higher the MERV value, the more efficient the filter will be at trapping airborne particles. When selecting a filter to combat the threat of airborne transmission, we suggest a MERV rating of 13 to 16.

 

Do you have an HVAC filter for residential applications? 

Yes, we recommend Puro-Green or DP-Green MERV 13 filters for use in residential applications. Our MERV 13 high-efficiency rigid filters can be used in residential HVAC systems to achieve better indoor air quality without the need to retrofit systems.

Conclusion

Today's historic global pandemic has raised awareness of the importance of maintaining healthy breathable air inside buildings. Parker is dedicated to providing honest and transparent information about our filtration products to help customers decide which technologies offer the highest chances of trapping virulent pathogens before they enter a building or circulate to different rooms. Parker’s products can reduce airborne particulate in a controlled environment. They would not eliminate the risk of exposure to airborne viruses but can be part of a comprehensive plan to help reduce that risk.

For more information and the full list of frequently asked questions, download the FAQ fact sheet.

 

Parker Purpose

After more than a century of experience serving our customers, Parker is often called to the table for the collaborations that help to solve the most complex engineering challenges. We help them bring their ideas to light. We are a trusted partner, working alongside our customers to enable technology breakthroughs that change the world for the better. 

 

This post was contributed by the HVAC Filtration Team.

 

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Reliable functionality and efficient economy are the key drivers to the innovation in the development of marine engines. Improvements in the design efficiency in the maritime industry over the past three decades show engine applications have had the largest increase.

Current filtration practices in hydraulic and lubrication throughout marine applications center around preventing contamination from getting into the machinery, thereby delivering improved component life. However, purely prescriptive maintenance of filter elements causes unnecessary maintenance costs and unanticipated downtime. Our white paper demonstrates why a move to more predictive maintenance with condition-based maintenance of filter elements enables the operations team to optimize the use of resources.

 

Download our technical white paper: Towards the Predictive Maintenance of Mechanical Filters to learn about the scientific testing behind the data substantiating the results.

      Factors that influence the mechanics of filtration

Combustion and lubrication are complicated events with usual uncertainties in their operating conditions. A mechanical filtration system is an integral part of lubrication and combustion units, and may display an uncertain performance due to the sensitive behavior of several upstream and downstream components. On one hand, the flow and fluid characteristics along with the varying ambient conditions strongly impact the filter’s performance. On the other hand, unpredictable characteristics of contamination including the particle size and shape, specific weight and concentration of solids, the chemical composition of impurities and diverse intermolecular and adhesive forces highly influence the mechanics of filtration. The source of foreign matter in hydraulic liquids and underlying mechanisms of generating solid particles such as wear, welding slag, ingressed contamination, etc. is very complex, and a holistic analysis from the perspective of the system’s entirety would lead to superficial knowledge about oil quality.

 

Moving from preventive to predictive maintenance

The presence of solid particles in the lubricant is a major cause of failures in hydraulic systems. Studies show that over 80% of the failures of hydraulic units are due to the foreign matter in the hydraulic oil. From a combustion perspective, stringent regulations on the emissions and realistic certification processes demand more efficient filtration practices.

The conventional practice of preventive maintenance of mechanical filters is purely time-based. This may cause additional maintenance costs if the filter element is still in relatively good condition, and unanticipated operational downtime if the element is clogged or damaged before its prescribed lifetime. Therefore, the need for switching from preventive/reactive maintenance to predictive maintenance is obvious, where the information about the element’s lifetime is critical without missing the focus on the optimal response to the key performance requirements:

• Oil cleanliness

• Sustainability

• Serviceability

• Safety

 

Optimizing filter predictive maintenance with sensors

In order to optimize the filter’s maintenance, the analysis of the performance over time must be precise. This objective can be achieved by improving the quality and relevance of the filter’s test data provided by the deployed sensors at the right locations of the test bench. Performance and statistics based predictive approach rely on the robustness and validity of the models that correlate influential factors to enable more accurate estimations of the filter element’s lifetime.

Predicting the lifetime of a mechanical filter is, therefore, a major challenge due to the dynamics associated with the filtration as a process itself. Depending on the areas of application, this estimate requires knowledge about all those processes that alter the operation settings, fluid condition, porous media properties, and the filter’s status.

 

Developing a framework for the data correlations

The rapid growth of sensing technologies has made oil condition monitoring a reality. However, the dynamics associated with the phase separation through porous media and ambiguous variation in the filtration phenomenon due to the uncertain operating conditions unleash the complexity in realizing the prognostics of a hydraulic or fuel filter.

 

 

Therefore, a laboratory-based experimental framework has been developed to quantify the effect of fluid/flow conditions on filtration. Here, the identification of the right filtration parameter should lead to the analysis of the filter element’s condition and predict its residual lifetime.

A smarter shift to condition-based maintenance

As a filter’s maintenance practices cause unnecessary maintenance costs and unanticipated downtime, condition-based maintenance enables the optimum utilization of resources. This foresees a new horizon where the preventive or reactive maintenance could be replaced by the state-of-the-art predictive maintenance models in the context of industry 4.0 and the IoT.

 

Download our technical white paper: Towards the Predictive Maintenance of Mechanical Filters to learn about the scientific testing behind the data substantiating the results.

 

Article contributed by Jagan Gorle Ph.D., principal R&D engineer at Hydraulic & Industrial Process Filtration Division of Parker Hannifin in Finland. 

 

 

 

 

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During downstream processing, the value of a product increases with every unit step of the operation, designed to both remove impurities and concentrate the biologically active component.

Each of these unit operations involves a significant cost to the biopharmaceutical manufacturer. From cell harvesting and clarification, through affinity chromatography, buffer exchange, cation exchange chromatography, viral reduction, anion exchange chromatography, viral inactivation, concentration, sterile filtration and filling, value is added and is incremental.

 

Cost breakdown

Affinity chromatography (such as the Protein A chromatography step), the initial concentration and purification step in downstream processing, is typically the most expensive unit operation – and costs of up to $20,000 per litre of chromatography resin can be incurred. Consider the following scenario: if very wide chromatography columns are used – for instance at 2m diameter x 30cm bed height – this would amount to almost 1000 litres of Protein A resin.

The final cost will depend on the process and volumes, and some processes may use much less. But even a 30cm diameter x 30cm bed height Protein A chromatography column, which would amount to approximately 21 litres of Protein A resin, would mean a consumable cost of more than $400,000.

Each subsequent step in downstream processing inherently increases the value of the final product. And any loss of product or contamination following the Protein A chromatography step would be very costly indeed, given the consumable costs associated with it.

In addition, as well as consumable costs, there are also costs associated with the time and resources allocated to each step, in terms of operator hours and training.

By the time the product reaches the final sterile filtration step, it is highly purified and concentrated and has reached its highest monetary value, It is now ready to be vialled into smaller quantities for use in the medical field. This is typically carried out at another location specially designed for filling vials and therefore needs to be shipped in bulk.

 

Costly mistakes

Prior to this, the bulk drug substance has traditionally been manually dispensed into smaller quantities to safeguard the batch. However, this method is prone to human error.

Imagine an operator working in a high-stress, high-pressure situation, manually operating pumps and valves, while struggling to also read a balance – it is easy to see how costly mistakes can be made.

 

So how can we ensure that the final product is protected?  

Automating and enclosing bulk fill operations can reduce the risk of human error in the bulk filling process. For instance, by using this method there is no open manual manipulation of tube sets, which is a very real potential source of product loss. In addition, by standardizing the process and simplifying training, variations in the process are eliminated.

 

Parker's  SciLog® FD system

The Parker Filtration Innovation Center houses the research and development for all of Parker Hannifin's filtration products. This 82,000 square foot facility is dedicated solely to the discovery of new filtration technologies and proprietary manufacturing processes and is one of the largest centers of its kind in the industry. Our dedicated team of engineers, Ph.D. scientists, U.S. military veterans, and industry experts have helped Parker secure over 500 U.S. patents and 1,200 global patents in the filtration focus. More recently, the use of robotics and automation for advanced manufacturing has been a solution for creating new filtration methods that ensure quality and delivery to our customers.    

The world’s leading nanofiber lab is housed within the innovation center where our dedicated engineers are constantly innovating new filter media. Parker’s nanofiber technology is cutting edge in regard to filtration efficiency.

The inspiration for our constant innovation comes directly from our customers. Through our “New Product Blueprinting” program we interview our customers using an open, structured approach to discover and create solutions for their filtration needs. We work to develop new filter media and filter elements that design engineers can then blueprint their new products and equipment around.

While it may not be obvious, Parker filtration technologies can be found in much of what we use. Our goal is to protect and purify for our customer toughest applications with diverse solutions. We aim to improve the lifespan of our customers' equipment, help reduce their total cost of ownership, but not only that — we are inspired to make the communities in which we work and live better.  

Read on to meet our team of filtration experts and learn more about the Innovation Center.
 

For more detailed information about the new Innovation Center, including videos, product innovations and brochure, visit our website.

 

Widest range of filter applications in the world  

Parker filtration product technologies serve the widest range of filtration applications in the world, spanning engine mobile, hydraulics, industrial HVAC, water purification and life sciences filtration. 

At the innovation center, we work with twelve proprietary filtration media technologies and have multiple certifications in robotics and machine design — all for the advancement and improvement of filtration technologies. Our state-of-the-art nanofiber lab, one of the largest in the world, is where we have created two proprietary methods of producing filtration media called Protura™ and ForceSpinning™.

To improve the quality of product and delivery, we use advanced manufacturing solutions in the methods of automation, simulation, and robotics.

 

"Parker’s purpose is to enable engineering breakthroughs that lead to a better tomorrow and, I am proud to work for a company whose goal is just that.

We are dedicated to constantly innovating new filtration technologies that not only improve the lifespan of our customers' equipment but aim to make a real difference in our community and for our world by protecting and purifying for our customers' toughest applications with diverse solutions. I am proud to work alongside U.S. military veterans, Ph.D. scientists, engineers from many disciplines and industries, and machine safety experts."

— Ryan Pastrana, director of innovation, Parker Filtration Innovation Center

 

 

The science behind nanofiber technology  

"A nanofiber has a diameter of one billionth of a meter, this is approximately 1000 times thinner than a human hair. This level of technology offers excellent filtration efficiency while maintaining low flow restriction. This means less energy consumption — an engine will have better fuel economy, an HVAC system will cost less to operate, and a power plant can generate more electricity. Parker practices multiple methods of producing nanofibers so that we can tailor the media structure to the widest range of applications to the specific industry."

— Yatin Rane, Ph.D., scientist, Parker Filtration Innovation Center

 

 

The science behind embossed deep pleat construction

"Having great filter media is only half the battle. Many excellent textiles used as filter media don’t result in great filter elements because the form of the final filter element doesn’t take advantage of these properties well. Parker has developed methods to emboss three-dimensional structures into the media to take advantage of media properties. This allows pleat shapes to maintain their form over the life of the filter so that the filter can hold more dust, thus increasing the life of the element. This leads to a longer time between filter changeouts, allowing operators to run equipment longer. Embossed shapes can also help steer airflow to allow for unique shapes that can fit under the hood of a cramped engine compartment or vent system. This leads to lower initial costs for new system designs."

— Heath Mann, project coordinator, Parker Filtration Innovation Center  

          

 

Aerospace tools for filtration and advanced design  

"Parker’s Filtration Group has both the application expertise of filtration and the same skills and tools used in the aerospace industry to leverage advanced design modeling of our filtration systems. These tools help us design more efficient systems and accelerate time to market for new products by reducing time-consuming empirical testing because we’ve used computer models to get closer to final design before we even build the first prototype."  

— Sucharitha Rajendran, Ph.D., modeling and simulation engineer, Parker Filtration Innovation Center  

 

 

Real-world testing   

"Before we test a product in the field we test them in our validation rigs to be confident that our filters will withstand the harsh conditions of real-world scenarios. One example of our validation equipment is the filter test for gas turbine inlet air. This rig can alter temperature and humidity while constantly injecting dust and salts into the filters for hundreds of hours. We use this method of testing to ensure equipment used in a facility like a power plant is protected from the environment regardless of weather conditions. Whether it be extreme temperature conditions, vibration, or a combination of contaminants that simulate different parts of our planet, we use our application knowledge to verify our products can withstand extreme external challenges."  

— Chet Hale, controls engineer, Parker Filtration Innovation Center 

 

 

Filter media expertise

"Filter media is the heart of our technology. With the broadest portfolio of filtration solutions in the industry, Parker’s expertise in media is world-class. We’ve characterized every grade of media ever used by Parker as well as we’ve found in the industry and created a database of hundreds of types of media. We use this information to accelerate new product development. For instance, media once used in a refinery application may be used in construction vehicles or in HVAC systems. By sharing the combined knowledge of all our divisions, we can further promote ourselves as leaders in the industry, and I'm really excited to be a part of that."  

— Tyrone Wells, Jr., Ph.D., lab manager, Parker Filtration Innovation Center 

 

 

Conclusion

The Parker Filtration Innovation Center houses the research and development for all Parker Hannifin filtration products, spanning a range of technologies including engine mobile, hydraulics, industrial HVAC, water purification and life sciences. The Innovation Center is one of the largest filtration R&D facilities in the nation and is home to the world’s leading nanofiber lab. Our team of engineers, Ph.D. scientists, U.S. military veterans, and industry experts are dedicated to constantly innovating new filtration technologies that not only improve the lifespan of our customers' equipment but aim to make a real difference in our community and for our world by protecting and purifying for our customers' toughest applications with diverse solutions.

 

 

For more detailed information about the new Innovation Center, including videos, product innovations and brochure, visit our website. 

 

This post was contributed by the Filtration Team

 

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Understanding the Different Stages of Oil & Gas for Filtration Systems

Process chillers for precision cooling of low viscosity industrial fluids are routinely used in hospitals and laboratories to control the temperature in a variety of applications including rotary evaporation, reaction vessel jacketing, diffusion pumps, laser systems, electron microscopes and linear accelerators. Two of the most prevalent applications of this technology include heat load management in magnetic resonance imaging (MRI) and computed tomography (CT) scanners.   

This blog explores how process water-chilling technology is applied to these critical applications.
 

View the interactive to learn how precision water chillers are used in medical and laboratory applications.

    Magnetic resonance imaging 
  What is an MRI scanner?

MRI (magnetic resonance imaging) is a non-invasive scanning technology that produces cross-sectional images of the body. It is used in a range of medical fields including: 

• Musculoskeletal
• Gastrointestinal
• Oncology
• Cardiovascular
• Neuroimaging 

MRI scanning can differentiate soft tissue structures in any plane, making it an invaluable diagnostic tool. MRI scanners generate a strong magnetic field that is used in conjunction with radiofrequency currents to stimulate specific molecules in the body. The behavior of the molecules can be used to generate a three-dimensional image of body tissues. Example MRI images are shown below:

 

MRI operation and cooling requirements
  Cold head recondensing of helium 

All MRI scanners contain superconductive magnetic coils. These coils must be cooled to approximately -296° celsius to promote superconducting properties in the metal alloys. The low cooling temperature is achieved by circulating liquid helium around the magnetic coils.

An average-sized MRI scanner contains approximately 1,700L of helium. A mechanical device called a “cold-head” is used to minimize the loss of helium. The device re-condenses gaseous helium back to a liquid state after contact with the magnets.

Below is a diagram of the cold-head circuit:

 

Heat load reduction

In addition to controlling the ambient temperature around the MRI scanner, heat must be removed from several processes during machine operation. These include:

• A helium compressor is used in conjunction with the cold-head to compresses the gaseous helium prior to recirculation to the MRI magnet. The heat load from the compressor motor must be removed to maintain the efficiency of the helium circuit.
• RF cabinets and amplifiers generate electrical heat that must be removed in order to protect the equipment from heat-related failures.
• Direct cooling around the magnetic coils is employed to remove ambient heat and improve the magnet cooling efficiency (compliments the HVAC control of the room temperature).

 

Benefits of using a water chiller for an MRI scanner

Chillers can be integrated into the MRI system to provide cooling capacity in several ways. In most instances, the chiller is used in conjunction with a heat exchange cabinet (HEC) located in the equipment room (kept separate to the magnet room). The HEC utilizes heat exchangers that can be connected to the water supply from the chiller. 

Below is an example layout of the HEC:

 

Computerized tomography scanning 
  What is a CT scanner?

Computerized tomography (also referred to as computerized axial tomography, CAT) is a scanning technique that uses x-ray to produce cross-sectional images of the body. The images provide more detail of body structures when compared to a standard x-ray. Hospitals have a high demand for CT scans due to the range of diseases and conditions that can be diagnosed. 

The CT scanner uses motorized x-ray tubes that move around the patient. The x-ray that passes through the patient is picked up by detectors that send the data to a computer for processing.

 

Benefits of using a water chiller for a CT scanner 
  Heat load reduction

• The electrical componentry and x-ray tubes in CT scanners draw >95 KW of power. Excess heat in the scanner gantry must be removed on scan completion to allow for the next scan to be initiated.
• Shortened cooling time - the x-ray tubes can take between 20 – 30 minutes to cool sufficiently without assistance. A water chiller significantly reduces the cooling time and protects the scanner from overheating. Patient throughput, enhanced care and hospital efficiency are greatly improved. Unnecessary maintenance related to process overheating is also reduced helping to drive down overall operation costs.

 

Why Parker chillers?

The Parker Hyperchill Water Chiller has a proven track record of performance with all the major manufacturers of MRI and CT scanner systems. Key benefits include:

• Non-ferrous hydraulic circuit for increased reliability and reduced maintenance costs.
• Large water tank capacity increasing both process cooling stability and compressor lifespan. Reduced maintenance cost and hence the cost of ownership.
• Built-in maintenance indicators and fault switches safeguard the capital equipment.
• Configurable with a 5 bar pump to meet system pressure requirements.

 

Conclusion

The selection of the most reliable and efficient water chiller will help assure the uninterrupted use of MRI and CT scanners in diagnosing patient conditions. Parker Hyperchill Chillers offer state-of-the-art components and systems that protect these valuable assets from heat-related failures, improve efficiency and assure consistent, trouble-free performance.  

 

Parker Purpose

After more than a century of experience serving our customers, Parker is often called to the table for the collaborations that help to solve the most complex engineering challenges. We help them bring their ideas to light. We are a trusted partner, working alongside our customers to enable technology breakthroughs that change the world for the better. 

 

View the interactive to learn more about the use of precision water chillers in medical and laboratory applications.

 

This post was contributed by James Brown, compressed air and gas treatment/analytical gas sales manager and Filippo Turra, product manager, Parker Gas Separation and Filtration Division EMEA

 

 

 

 

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Learn more about Parker's solutions for Healthcare and Life Science Industry

 

For over 100 years, compressed air has been recognised as a safe and reliable power source that is widely used throughout industry. Known as the fourth utility, approximately 90% of all industrial manufacturing companies use compressed air in some aspect of their operations. Unlike gas, water and electricity which is supplied to the site by a utility supplier to strict tolerances and quality specifications, compressed air is generated on-site by the user. The quality of the compressed air and the cost of producing this powerful utility is, therefore, the responsibility of the user.
The problem with compressed air

Compressed air systems inherently suffer from performance and reliability issues and almost all the problems associated with the compressed air system and many manufacturing related quality issues can be directly attributed to contamination found in the compressed air.

 

This extract has been taken from the white paper "Compressed Air Contamination". Download the full whitepaper.

   
Compressed air contamination sources

Unknown to many compressed air users, the compressed air system contains a large array of both visible and invisible contamination which originate from four different sources.
 

The four sources of compressed air contamination:

1. The ambient air
2. The air compressor
3. The air receiver
4. The distribution piping

 
1. Ambient air

The primary source of contamination found in a compressed air system is the ambient air surrounding the compressor. In simple terms, the air compressor is just a large air mover. When operating, it pulls in large volumes of air around it, squeezes it and pushes it out down a pipe. However, when doing so it also acts as a large vacuum cleaner, pulling in invisible contaminants. So, when the ambient air is compressed, the compressor is also concentrating the contamination at the same time.

Main contaminants found in ambient air:

• Water vapour
• Micro-organisms
• Atmospheric particulate
• Oil vapour

Additional contaminants found in ambient air:

The four contaminants highlighted are the main contaminants of interest for general applications, however, there are also other contaminants entering the compressor intake, which depending upon how the compressed air is used, may also require focus. The additional contaminants include:

• Sulphur dioxide (SO2)
• Nitrogen oxides (NO + NO2)
• Carbon monoxide (CO)
• Carbon dioxide (CO2)
• Vapours from caustic cleaning agents, bleach, etc.

 
2. Air compressor

During the compression and cooling process, the air compressor also changes the phase of the invisible gaseous contaminants it has ingested, and with a change of phase, many invisible contaminants now become visible. In addition to changing the phase of the ambient contaminants, the air compressor is also responsible for adding contamination of its own, making it contamination source number two.

Contaminants added by the air compressor:

• Liquid oil
• Oil aerosols
• Oil vapour (from compressor oil)
• Wear particles

Ambient contaminants converted by the air compressor:

• Oil vapour
• Water vapour

Both gaseous contaminants cool and condense to form:

• Liquid oil
• Oil aerosols
• Liquid water
• Water aerosols

So, by the time the air exits the compressor aftercooler and no matter what type of compressor is used (oil-lubricated or oil-free), the following contaminants will be present in the compressed air:

• Liquid water
• Water aerosols
• Water vapour (100% saturation)
• Liquid oil
• Oil aerosols
• Oil vapour
• Micro-organisms
• Atmospheric particulate and compressor wear particles

3. Air receiver

Contamination source number three is the air receiver. Installed in a compressed air system to store compressed air and increase the efficiency and reliability of the compressor, the air receiver also stores large quantities of contamination. These contaminants also lead to chemical reactions and oxidation which in turn, lead to additional contaminants being added to the compressed air system.

Contaminants added by the air receiver:

• Rust
• Pipe scale

The wet air receiver (a receiver installed before a dryer) can reduce the compressed air temperature by up to 5°C. This cooling will cause further condensation of oil and water vapours into liquid oil and water. A wet air receiver is often chosen for this purpose as it can provide additional cooling of the compressed air at times where the ambient and compressed air temperatures are higher than expected. Unfortunately, it also provides the ideal environment for the rapid growth of micro organisms, especially in the compressor condensate.

4. Distribution piping

In a typical compressed air system, the final source of contamination is the distribution piping which takes the compressed air from the compressor and distributes it around the manufacturing facility. Just like the air receiver, the distribution piping not only stores contamination, it also adds to the contaminant problem, through chemical reactions and oxidation, again adding rust and pipe scale to the compressed air and allowing the growth of micro-organisms.
 

Contaminants added by the distribution piping:

• Rust
• Pipe scale

As with the air receiver, the distribution piping will also cool compressed air causing further condensation of oil and water vapours into liquid oil and water which in turn form aerosols of oil and water as the air pulls the liquid along the piping.

Contaminant summary

To protect equipment and processes that use compressed air or products that have direct or indirect contact with compressed air, there are a minimum of ten contaminants originating from four different sources that must be treated.

Contamination entering the compressed air system     
 
Breathing air / medical air

If the compressed air is used for breathing air, medical air or other critical applications, then additional, potentially life-threatening contaminants in the ambient air must also be considered.

Contaminants of concern for breathing air / medical air applications

• Sulphur dioxide (SO2)
• Nitrogen oxides (NO + NO2)
• Carbon monoxide (CO)
• Carbon dioxide (CO2)

Therefore, for breathing air / medical air / critical applications, there are a minimum of 15 contaminants that must be treated.

Contamination entering the compressed air system (breathing air):

    

Compressing air – the problem increases

To many, the ambient levels of contaminants may be considered “negligible”, however, when we talk about compressed air contamination, we must also consider the effect that compressing the air has on the ambient contamination, the amount of air flowing into the compressed air system and the time the compressor is operating.

The concentrating effects of compression

When operating, the air compressor is constantly pulling in large volumes of ambient air and as operating pressure and or flow rate increases, the greater the volume of ambient air is required. The greater the volume of ambient air, the greater the amount of contamination.
 
For example: In simplistic terms, to generate 1 cubic meter of air at a pressure of 7 bar g (8 bar A) requires 8 cubic meters of ambient air.

Myth

When the stored compressed air is used, it expanded back to ambient pressure and there are those that believe that when this expansion takes place, the levels of contamination return to the ambient levels and are, therefore negligible, This, unfortunately, isn’t true.

Fact

When the air is compressed, the heat of compression makes the compressed air too hot to use, so it must be cooled to a usable temperature. Intercoolers and aftercoolers are installed for the reduction of the compressed air temperature (either integrated into the compressor or fitted externally). As the air is cooled, condensation of the gaseous contaminants into liquids and their subsequent conversion into aerosols (very fine droplets) takes place in the coolers and unfortunately, the liquid separators supplied with the coolers are unable to remove 100% of the liquids and are completely ineffective on aerosol reduction. Therefore, untreated compressed air is heavily contaminated by the time it reaches the point of use.

The table below provides an example of just how contaminated 1 cubic metre of compressed air can be at a typical operating pressure of 7 barg (102 psi g).

Which contaminant causes the most problems?

It is often believed that oil introduced by the compressor causes the most problems in a compressed air system. However, oil is not the major problem everyone thinks it is.
 
The most problematic contaminants are water and microorganisms. The presence of one directly impacts the growth of the other.

 

Water causes:

• The growth of micro-organisms
• The formation of rust and pipe scale
• The production of oily, acidic compressor condensate

Oil is often perceived to be the most prolific contaminant as it is can be seen emanating from open drain points and exhausting valves. Usually, it is oily condensate (oil mixed with water) that is being observed.

So how big is the water problem?

The table below provides an example of how much water can enter a compressed air system per hour and per year.

The example used above is based upon a single compressor. If a compressed air system has larger compressors installed, runs for longer periods of time, is installed in a country with high ambient temperatures and/or relative humidity or a combination of all the above. then the volume of condensate in the system would increase significantly.

 

Summary

• There are many contaminants found in a compressed air system.
• Generally, for most compressed air applications, there are 10 contaminants that must be treated.
• Other contaminants present may also cause issues (application dependent).
• Contamination comes from 4 different sources, not just the compressor.
• Compressing air concentrates contamination found in the ambient air.
• Water is the most prolific and problematic contaminant, not oil.
• Liquid contamination will increase significantly in warmer, more humid environments.

 

The following extract has been taken from the white paper "Compressed Air Contamination" by Mark White. Download the full whitepaper.

 

 

This article was contributed by Mark White, compressed air treatment applications manager, Parker Gas Separation and Filtration Division EMEA

 

 

 

 

 

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