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A condition monitoring system is concerned with the early detection of failure. Vibration monitoring systems, whether they use traditional techniques based on displacement or acoustic emission sensor techniques, form part of your condition monitoring (CM) tool chest.
Machinery vibration analysis equipment is part of a machine monitoring system that aims to provide months of warning of developing issues before they become bigger problems. This can save your company from serious disruption by avoiding unnecessary downtime and delays. There is also the potential for both on and offline implementation of these systems, subject to capability and level of available technology for the techniques, which makes them perfect for the food and beverage, power generation, marine and offshore industries.
Vibration monitoring equipment uses techniques based on the use of accelerometers, which are well known in the field of CM, and can be classified into three main categories:
VM Vibration Monitoring (ISO 10816): Perfect for maintenance engineers, vibration monitoring ISO 10816 offers an instinctive understanding that a machine is vibrating unusually from the non-rotating parts. Great for small machines, electric motors and pumps and production motors.
VA Vibration Analysis (ISO 13373): A mainstream CM option and essential addition to any other technique used, vibration analysis offers a more sophisticated improvement in signal to noise ratio for repetitive defect signals. This highlights what is internally causing the vibration.
AE Acoustic Emissions (ISO 22096): This technique looks for high-frequency signals from cracks or impact rather than a repetitive movement from vibration. As a passive technique, acoustic emissions can diagnose incipient machinery prior to undertaking a lengthy diagnosis. Highly effective in detecting the very early onset of machinery fault conditions where needed most.
There are many approaches which fall under the umbrella term condition monitoring, each with its own features and areas of excellence. These include machinery vibration monitoring and analysis, and also acoustic emission analysis systems.
Techniques in BLUE = Technologies available from Parker Kittiwake
Parker Kittiwake focuses on techniques such as an acoustic emission system that provides for the greatest protection or longest period of warning for potential damage and eventual failure. While machine vibration monitoring systems can help prevent the worst cases of damage.
The use of two (or more) appropriate technologies can provide a more complete picture of the likely failure mechanism, thus offering you reduced machinery downtime and more efficient recovery. The table below identifies the variations of expertise that different condition monitoring options cover.
CM machinery techniques that are available from Parker Kittiwake:
Article contributed by the Hydraulic Filtration Team, Parker Kittiwake, part of Parker's Hydraulic and Industrial Process Filtration Division.
Additional resources
Bunker Quality: Why Changes to ISO 8217 Increase the Need for Condition Monitoring
What You Need to Know About Testing Your Hydraulic System for Particle Contamination
Reduce Failure of Hydraulic Systems with Preventive Maintenance
Reliability Centered Maintenance Reduces Costly Downtime in Oil & Gas Applications
A common goal shared by virtually all industrial manufacturing businesses is to assure safe and clean air quality throughout their production facilities. Using an inadequate air filtration system can result in unplanned interruptions in production and unsafe working conditions — which work directly against a company’s financial performance and brand image.
As an alternative to installing an expensive new baghouse, many companies are opting to use their existing infrastructure and upgrade their baghouse filter technology, with positive results. This strategy allows companies to reduce costs, lower routine maintenance and minimize unexpected production interruptions — without making a substantial capital investment.
Key goals in baghouse design and operation
Baghouse operators aim to meet the following goals while maintaining a constant inlet air load:
One solution that is rapidly gaining in popularity is the transition from traditional filter bags used in baghouses to BHA® PulsePleat® filter elements. This state-of-the-art technology is being installed at manufacturing facilities across the globe and in a wide range of industries — with impressive results.
Featuring an increased surface area with a reduced footprint compared to traditional filter bags, the material and construction used in BHA® PulsePleat® elements offer the following benefits:
Production increases over several years had led to higher grain loading to the baghouse and to extremely high air-to-cloth ratios (10:1) in a tabulation and pill coating application at a pharmaceutical company.
Filter bags had to be replaced every 4-6 weeks due to the high differential pressure, and excessive blinding of polyester felt media. The frequent bag changes required constant maintenance and unscheduled production downtime.
The solutionPlant management was concerned that a new baghouse would be required. They contacted Parker Hannifin's environmental services team for advice. After reviewing the application, Parker's team recommended a retrofit of the existing dust collector with BHA® PulsePleat® filter elements.
ResultsImprovement was noticed immediately after installation, with the following results:
Parker Hannifin, a leader in filtration markets worldwide, offers the technical knowledge and product portfolio required to implement comprehensive measures to achieve productivity, efficiency and financial goals without capital investment. Parker engineers assist companies in identifying the areas of opportunity in their current air filtration infrastructure and make specific proposals to help the customer achieve their goals.
Can BHA PulsePleat Filter elements help you? To learn more about BHA® dust collection products, watch this video:
This article was contributed by the Filtration Team.
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Whether you choose distillates, liquefied natural gas (LNG) or scrubbers to meet the new International Maritime Organization (IMO) fuel regulations in 2020, it will be even more critical to regularly monitor the condition of vital equipment to ensure there is no adverse effect on operational efficiency.
Understanding the physical characteristics of fuel, hydraulic and lubricating oil, coupled with an awareness of sampling and testing systems and processes, the significance of test results will become vital for engineers and operators. With the industry disjointed on how best to achieve compliance, it’s difficult to predict what the multi-fuel market of the future will look like. Indeed, it is likely to comprise a whole range of options, chosen to suit a host of factors including vessel type, size, and operating pattern – all of which will be influenced by fuel price.
The Parker Kittiwake Cat Fines Test Kit provides early forewarning of these destructive particles and gives a vessel’s crew maximum opportunity to take corrective steps. The Cat Fines Test has been designed to flag up HFO samples that may be contaminated with dangerous levels of cat fines before the fuel has even been pumped aboard. This simple, wet chemistry, on-board test identifies the presence of abrasive silicon and aluminium fines in HFO. The test is simple to perform, cost-effective and can be completed within a few minutes. Experimental results demonstrate that the new test is capable of identifying those fuel samples that have a cat fine concentration of > 60 ppm (Al + Si), and which therefore exceed the limit recommended by ISO 8217:2012. In fact, the test has been specifically designed to provide the crew with a clear sail or don’t sail indication with regards to fuel quality.
Cat fines will damage fuel injection equipment. The fines are particles of spent aluminium and silicon catalyst that arise from the catalytic cracking process in the refinery. The fines are in a form of complex alumino-silicates and, depending on the catalyst used, vary both in size and hardness. If not reduced by suitable treatment, the abrasive nature of these fines will damage the engine, particularly fuel pumps, injectors, piston rings and liners.
Catalyst Fines (Al & Si)
If stored for long periods of time, catalyst fines may settle out of the fuel and build up as sediment in storage tanks. If the tanks are not drained regularly, this sludge can be disturbed in heavy weather and enter the fuel system.
The figure shows the distribution of combined aluminium and silicon in residual fuel worldwide. It may be seen that over 90% of the samples have a combined aluminium value less than 40 mg/kg. ISO 8127:2010 contains a limit for aluminium and silicon combined of 60mg/kg for residual fuel categories RMG and RMK. There are lower limits for lower viscosity fuels.
Reduction of catalyst fines to an acceptable level for inlet to the engine takes place in the settling tank and the centrifuge. The extent of this reduction depends on the water content of the fuel, as catalyst fines are “hydrophilic”, in that they attract water and become contained in a water shell. Inclusion in the fuel of significant volumes of used lube oil may also limit the effective removal of fines.
The rate of settling is determined by Stokes’ Law, which takes account of the particle size, difference in density of the catalyst fine and the fuel, and the viscosity of the fuel. Various values are quoted for the density of catalyst fines, but in reality, they may be likened to honeycombed structures, which retard the rate of separation. This is further hindered by the outer shell of water by virtue of the close proximity of the density of water to that of the fuel.
The extent of the removal also depends on the height of the tank (fixed) and the size of the particles (variable). As far as the centrifuge is concerned, the critical factor is the relationship between the actual viscosity of the fuel and that for which the centrifuge was sized. If there is a difference in viscosity, the residence time of the fuel in the centrifuge will be greater than the design value; hence directionally the centrifuge should be able to remove fines of a smaller size. Whilst this approach is theoretically correct, the operational result is totally dependent on the size distribution of the fines. With the introduction of modern centrifuges without gravity discs, the recommendation is now to operate all available in parallel, which enables the flow through each to be reduced to the minimum practical level. The fuel is afforded the longest residence time in the centrifuges and the highest separation efficiency can be achieved. Combined output should be equal to the consumption. The temptation of using a higher rate so the daily service tank overflows back to the settling tank and is re-circulated should be avoided.
Article contributed by the Hydraulic Filtration Team, Parker Kittiwake, part of Parker's Hydraulic and Industrial Process Filtration Division.
Bunker Quality: Why Changes to ISO 8217 Increase the Need for Condition Monitoring
Fuel Switching: Monitoring to Prevent Damage
From food processing to coal handling to cement manufacturing, silos are used for bulk material storage in many industries.
Proper ventilation is critical to the preservation of the materials stored in silos. Bin vent dust collectors are often installed to filter and vent dust and debris that forms in the storage container.
Common goals for any manufacturing facility are to minimize unplanned equipment downtime and maintenance, maximize efficiency and lower operating costs. Lost production time and increased maintenance expenses work directly against the financial and production expectations of the business.
This was the case at one processing plant where multiple bin vent dust collectors were installed to vent silos. Operators were challenged with:
The plant turned to the filtration expertise of Parker Hannifin. Parker assessed the situation and recommended installing BHA® PulsePleat® Filter Elements as a versatile and cost-effective solution.
Standard benefits of BHA® PulsePleat® filter elements
The plant’s engineering and maintenance teams acted on Parker’s recommendation and installed BHA® PulsePleat® filters and realized the following results:
BHA® PulsePleat® filters helped the customer save nearly $16,000 in the first three years. They are now seeing a regular cost savings of over $3,000 every six months.
This post was contributed by the Parker Industrial Gas Filtration and Generation Division.
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The maritime industry is currently going through significant changes due to the introduction of tighter emission regulations. A stronger awareness in preserving the environment has pushed forward more stringent International Maritime Organization (IMO) legislation that imposes on ship owners and managers the use of new technologies that affect the day by day running of the vessel, starting with the choice of fuel, through changes in the engine operational parameters, and culminating in a severe reduction in allowable exhaust emissions.
The upcoming change to the permissible sulphur content of marine fuels burnt in the open ocean has brought the subject of compliance to the forefront. The most cost-effective way to meet the 0.5% sulphur limit is to blend the minimum amount of expensive, low sulphur fuel with the maximum amount of cheap, high sulphur fuel. Clearly, this leads to fuels that surf the compliance line very closely.
Of course, the issue of fuel compliance is not just restricted to sulphur. For instance, naval procurement often demands that distillate fuel supplies contain less than 0.1 % biodiesel [1, 2]. Recent technological advances mean that field spectrometers can measure sulphur and biodiesel concentrations within different fuels.
Download our white paper titled "The Science of Compliance" by Dr. David Atkinison to prepare for the upcoming change to the permissible sulphur content of marine fuels.
Unchartered operational territories
Combining these changes with the following factors
have prompted the marine industry to abandon the ‘comfort zone’ that has been enjoyed for the last 20+ years. Today’s environment has a significant impact in the way two-stroke, slow speed, diesel engines are managed, introducing new challenges for different fuel types, different lubricants and ancillary equipment required to meet the new requirements.
Unintended consequences
Field experience has shown that all these factors can lead to:
Solutions come in many shapes and sizes, from simple, two-minute handheld test kits to state-of-the-art online sensor technology. Through scientific testing, our lead-application engineers have demonstrated that a combination of these tools can deliver real savings by:
Two-stroke, slow speed, diesel engines are used in the marine industry to power the largest commercial ships currently sailing on the seas. These internal combustion engines are used for their high thermal efficiency, exceptional reliability and ability to use a variety of fuel types including residual oils. These fuels are, broadly speaking, the very end product of the crude oil refining process and are commonly referred to in the marine industry as Heavy Fuel Oil (HFO) or Residual Fuel Oil (RFO). These fuels are regarded to be the most cost-effective available; for this reason, they’re the preferred choice to power main engines and generators in large, ocean-going, vessels. HFO comes in several grades; the best and most expensive grades have the lowest Sulphur content.
Choosing HFO, however, presents challenges in dealing with the varying sulphur contents in:
These materials are carried over from catalytic cracking during the crude oil refining process and are referred to as catalytic fines or simply, ‘cat-fines’. The International Standards Organization has published a specification for marine HFO (ISO 8217:2010) which imposes upper limits on these, and other fuel parameters to provide consistency in the market. Nevertheless, bunkered HFO, even when conforming to these specifications, requires further onboard processing to reduce the water and solids contents to levels deemed acceptable for engine operation.
Regulations present challenges to operatorsIn the marine industry, environmental regulation is on the increase and operators are facing new challenges that threaten their cash-tight budgets. But it is not just the added cost of more expensive alternative fuels or lubricants that can impact operators, critically, it is also the effect that these changes have on the operating conditions of the vessel, leading to unexpected damage and causing unplanned downtime.
With such stringent and widespread regulations, compliance with the rules becomes even more challenging. New operating methods and procedures for fuel changeover, oils, and equipment required for compliance can indeed lead to unintended consequences such as damage caused by out-of-specification fuel or incorrect/insufficient cylinder lubrication.
Amidst the omnipresent drive for safety and operational efficiency, effective condition monitoring tools and techniques have never been more valuable in helping operators manage, avoid or mitigate these costly issues.
The proper combination of condition monitoring techniques provides a wealth of information, allowing ship operators to take immediate corrective actions to mitigate any damage, to allow continued, efficient operation and prevention of the high costs associated with undetected liner wear events. The savings associated with these early warnings far outweigh the cost of the condition monitoring tools used to detect them.
Are you attending the CIMAC 2019 Congress?
Visit Parker at Stand #316 to learn more about our energy efficient, high-performance solutions for combustion engine applications. The CIMAC international congress and exhibition, held every three years, is a unique opportunity to stay current with technology for the internal combustion engine industry and meet with specialists in the field. Our engineers are ready for your questions.
Article contributed by Dr. David Atkinson, principal chemist, Parker Kittiwake, part of Parker's Hydraulic and Industrial Process Filtration Division.
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Bunker Quality: Why Changes to ISO 8217 Increase the Need for Condition Monitoring
Today, the global supply and demand for liquefied natural gas (LNG) is approximately 300 million tons per annum (MTPA). Over the next five to ten years, demand is predicted to surpass supply. With such high use expected, LNG is a valuable commodity, commanding high market prices and delivering soaring profits to suppliers. That said, equipment used in the LNG production process needs to provide extended, reliable operation with maximum uptime and output.
Gas turbines are widely used as mechanical drives when compressing refrigerants as part of the LNG process. If a gas turbine used in the liquefaction process has unscheduled downtime, it can cost the LNG plant owner several million dollars a day in lost production. In fact, a single unscheduled turbine shutdown could result in the entire LNG train being taken offline, requiring lengthy shutdown and start-up procedures leading to huge financial losses.
Let's examine challenges faced by LNG turbine operators, factors that hinder turbine performance, and choosing filtration systems based upon operating conditions.
The challenge: keeping problems out of the turbine
Land-based refrigerant compressor stations are often located near coastlines for easier tanker access. LNG processing facilities may also be located on floating vessels for close proximity to offshore gas fields. In either case, gas turbines used in the oil and gas industry encounter extremely challenging operating environments. High levels of small particulate in the form of sand, dust and shot-debris from drilling, salt aerosols, and harsh weather conditions all threaten the performance and health of a gas turbine. Failure to address these contaminants can lead to reduced performance, expensive repairs, and eventually could cause a catastrophic failure of the turbine components.
The solution: inlet filtration
To protect the turbine from corrosion, erosion and fouling and keep it operating reliably and predictably over long periods of time, a carefully designed inlet filtration system is required. However, considering the massive volume of air passing through a gas turbine inlet, installing the correct system for the application conditions is critical. A filtration system that is correctly designed and engineered to meet the real-world conditions of the gas turbine installation, can mean shutdowns are limited to only scheduled maintenance periods. Choosing the wrong system can result in major financial repercussions.
Filtration system design
Typically, the filtration systems will incorporate multiple stages, sometimes as many as five. They will often include:
Prefilter stages: designed to remove larger particles and protect the higher efficiency filtration stages.
Coalescers: to remove liquid contaminants
Final filter Stages: To remove fine particulate and ensure clean air to the gas turbine, the materials used here are to be selected to meet the specific needs of the installation. This can include hydrophobic media and extended depth media.
Partnering with an expert in the specialized design of filtration systems for gas turbine protection, such as Parker Hannifin, can help to assure all considerations are met. Parker offers a range of filtration materials and engineering expertise for gas turbine protection.
Conclusion
It is widely accepted that an inlet filtration system is crucial for the reliable operation of gas turbines. Using the skills of leading experts in the field will help LNG suppliers take advantage of developing and improving filtration technology, thereby keeping their equipment running at optimum performance levels.
This article was contributed by Peter McGuigan, global LNG market manager, Parker Gas Turbine Filtration Division
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The ability to spot check the Sulphur content of fuel oil onboard a ship will help shipowners and operators ensure compliance with the latest IMO (MARPOL) regulations.
From January 2020 the maximum allowable Sulphur content of marine fuels is changing: for all areas outside the existing Sulphur Emission Control Areas (SECAs) the limit will be reduced from the current level of 3.50% m/m to just 0.50% m/m. Introduced by the International Maritime Organization (IMO), the new limit is being applied worldwide and covers the fuel oils used in main and auxiliary engines as well as in boilers. Compliance with the new regulations will be monitored by Port State Control.
For shipowners and operators, the new limit leaves little room for error. The traditional method of Sulphur level confirmation by Bunker delivery note significantly increases the risk of non-compliance and subsequent penalties, furthermore waiting for laboratory analysis is equally flawed as the vessel could have sailed by the time that is received and the Sulphur level found to be outside the specified limit. With this new equipment, bunkers can be sampled during delivery and noncompliance could be identified in the first few minutes of delivery (and at any other time interval) thereby preventing expensive de-bunkering and payment for non-compliant fuel.
"The fuel variation from port to port will be vast and furthermore, at present, fines and penalties imposed on non-compliant vessels in the special environmental control areas vary considerably. As such, ensuring uniformity in enforcement poses a hurdle."
Scott Herring, marine account manager, Parker Kittiwake
It will be essential for each vessel to know and comply with Sulphur limits of 0.10% m/m in SECAs or 0.50% m/m in all other areas worldwide. On-Board testing is one of the most effective means of establishing fuel compliance with Sulphur regulations.
Testing at sea, offshore or on land
As a lightweight, portable and self-contained X-Ray Fluorescence (XRF) spectrometer, the XRF Analyser enables in-situ lab standard testing of fuel oils at sea or on land. The XRF provides an accurate indication of sulphur content through the analysis of a small fuel sample in less than three minutes. This gives both shipowners and Port State Control (PSC) the ability to conduct laboratory-standard testing onsite, before non-compliant fuel is bunkered and before a vessel carrying non-compliant fuel leaves port.
The XRF Analyser can, for example, be used in the engine room or control room of a ship to test the Sulphur content of fuel oil as it is being delivered. Checking the fuel during delivery allowing ships personnel to verify that the Sulphur content shown on the bunker delivery note is correct, thus eliminating the risk of accidental non-compliance.
The XRF can be used by suppliers, brokers, surveyors and producers of bunker fuels. Faster and more accessible testing means that the XRF Analyser allows fuel oils to be tested more frequently and conveniently compared to sending samples to a laboratory. By allowing test results to be downloaded, or storing them for up to two years, the XRF Analyser also plays an important role in helping vessel operators to manage compliance audits more efficiently.
Traditional methods for confirming compliance with sulphur limits rely on paperwork requirements such as the Bunker Delivery Note (BDN). This not only significantly increases the risk of non-compliance and subsequent penalties for shipowners, but also heightens the environmental impact of burning fuel with a higher sulphur content. In addition, the delay incurred by laboratory analysis creates the risk that the vessel may have left port with non-compliant fuel onboard, or may require non-compliant fuel to be de-bunkered and compliant fuel re-bunkered, incurring significant delays and additional cost. The XRF Analyser provides a spot-check analysis of the sulphur content in fuel on site, allowing PSC to ascertain compliance almost instantly, and affording shipowners the opportunity to avoid fines, plus the time, expense and operational impact of bunkering non-compliant fuel.
“The XRF Analyser is factory calibrated according to ISO 8754 and makes field measurements that correlate strongly with ISO 8754 laboratory measurements."
Dr. David Atkinson - Principal Chemist
Measure lube oil performance and accelerated wear
In addition to measuring the Sulphur content in fuel oils, the XRF Analyser can be used to measure a range of other elements that are common contaminants which can affect lube oil performance and indicate accelerated wear conditions. Wear elements measured by the Parker Kittiwake XRF Analyser and their likely sources on board a ship (if any):
Portable XRF Analyser
The XRF Analyser combines simplicity with accuracy. Its standalone operation means that it offers immediate plug-and-play operation. Integrated into the small, lightweight housing is a high-resolution LCD touch-screen display which enables fast operation and delivers clear results.
The operator simply draws the sample of fuel oil from the ship’s system into the sample container, places it in the XRF Analyser and presses the test button. As the sample is not damaged or altered during testing, it can be retained for any additional sample analysis.
The result of the test is displayed the percentage of Sulphur in the sample. This helps to avoid ambiguity and human error by eliminating the need for the operator to interpret the test data.
A proven partner
The XRF Analyser is part of Parker Kittiwake’s range of condition-monitoring
equipment. This equipment is used where maximum efficiency and total confidence are vital in protecting capital plant and equipment. Our equipment is used extensively throughout the Marine, oil and gas, energy generation, aviation and industrial sectors. Sustained investment in R&D over the past 25 years has enabled Parker Kittiwake to produce best-in-class systems for the accurate monitoring and analysis of in-service lubricants, hydraulics, wear metals, fuels, gasses and acoustic emissions. In addition to ensuring compliance to global regulations, Parker
Kittiwake’s conditioning-monitoring systems are used to provide the earliest indication of failure. This enables operators to use predictive and proactive maintenance to minimize repair costs and extend the lifetime of the equipment.
By supporting an intelligence-led approach to maintenance, condition-monitoring equipment can significantly reduce system downtime and make a direct contribution to increasing productivity and profitability.
Parker Kittiwake is a $16.5bn engineering corporation, serving customers from a worldwide network of technical support centres. Winner of the Lloyds List Engineering Award, 2016, Parker Kittiwake holds several patents and its systems are used to monitor many thousands of vessels over the past 25 years at all levels of sophistication value and complexity. In every case giving the operator vital information in advance of the action required.
As a global leader in condition-monitoring equipment, Parker Kittiwake is synonymous with efficiency and innovation and is trusted to ensure the highest levels of protection.
Please download the XRF Analyzer Brochure to learn more
Article contributed by Dr David Atkinson, principal chemist, Parker Kittiwake
Other related articles on this topic:
Fuel Switching: Monitoring to Prevent Damage
Bunker Quality: Why Changes to ISO 8217 Increase the Need for Condition Monitoring
Additive manufacturing or 3D printing is a relatively new rapid manufacturing technology that has become mainstream in recent years. It covers a wide variety of processes used to produce a multitude of components ranging from automotive and aerospace prototypes to bespoke jewelry.
Before additive manufacturing, prototype products, as well as finished components, were generally machined or moulded in some way that involved processes such as, turning, milling, boring, grinding, spark erosion, injection moulding and casting. These processes are laborious, expensive and time-consuming for one-off and small batch production and sometimes involved many weeks of pattern or tool making before the desired result emerged.
Additive manufacturing has revolutionised this process by providing a rapid, low-cost method of producing components from the simple to extremely complex within a single machine. In most cases, software is used to program the additive manufacturing machine with the desired components parameters which it then produces, for example, from powdered polymers, powdered metals or photopolymer resins depending on the exact additive manufacturing machine and technology employed.
One of the leading authorities in establishing international standards for additive manufacturing technology is the American Society for Testing and Materials, ASTM. ASTM group F42 is the specifically designated body of experts that have compiled a set of standards identifying seven categories of industrial additive manufacturing processes.
A brief and simplistic overview of the seven additive manufacturing processes 1) Powder bed fusion
This category incorporates direct metal laser sintering, (DMLS), selective laser sintering, (SLS), electron beam melting, (EBM) and selective heat sintering, (SHL). These applications utilise a powdered metal or polymer that is selectively targeted by laser or electron beam to melt and fuse the layers of powder into a solid shape.
Incorporating 3D laser cladding and direct metal deposition, (DMD). Generally, metals in either powder or wire form are melted using a laser or electron beam and deposited in a layer to build the shape required. Can also be used for polymers and ceramics.
Uses a photosensitive resin contained within a vat. The resin hardens when exposed to ultraviolet light. The component is built up in layers on a platform that moves downwards during each cure cycle.
Utilises a powder and a liquid binder. Alternating layers of binder and powder are deposited along “x” and “y” axes from a printing head to build the required shape.
Operates in a very similar way to an inkjet printer except that a melted polymer or wax is built up in layers and solidifies in air or sometimes with the aid of UV light.
Polymer material is heated as it is extruded under constant pressure through a nozzle that moves horizontally over a platform that moves vertically. The component is built up layer by layer.
Is a low temperature, low energy process that bonds but does not melt the material. Thin sheets of metal are laminated one at a time using ultrasonic energy. The process requires further machining or laser cutting to remove the unlaminated metal and produce the final product. Typical metals such as aluminum, copper, titanium and stainless steel can be used.
Of the seven main types of 3D printing, Powder Bed Fusion most commonly uses inert gas to prevent oxidisation during the additive manufacturing process.
The need for inert gas in powder bed fusion
The powder bed fusion process takes place inside a virtually sealed chamber. Powdered polymer or metal is layered onto a platform that moves down in a vertical direction. The required shape is created by a laser melting the appropriate area of each layer of powder. As it solidifies, the platform drops, and the next layer of powder is added.
The chamber needs to be initially purged of ambient air using inert gas before the process starts and then a trickle flow of inert gas is needed to maintain the low oxygen atmosphere to prevent the heated powder from oxidising as it cools and solidifies.
For most applications using polymers and metal powders, nitrogen gas is ideal to use for the chamber inert atmosphere. Depending on the material, a Parker nitrogen generator can produce between 5% to 5ppm maximum remaining oxygen content, continuously, consistently and at very low cost to the most economical purity level required. For use with Titanium powders argon is the preferred choice. This is because nitrogen can react with titanium in a process called “nitriding” that can cause embrittlement.
Because nitrogen gas can be generated at such a low cost compared to cylinder and liquid supplies, it may also mean that expensive chamber gas atmosphere monitoring and recycling systems are unnecessary.
Parker NITROSource gas generation systems are flexible and expandable, producing as little or as much gas as required to exactly the right purity.
There are no cylinders to manage with all of the costs and manual handling risks associated with them or the expense and hassle of a bulk liquid supply.
As the additive manufacturing process takes time to produce the finished component, a small nitrogen generation system with a nitrogen storage vessel is often a very economical solution. The generator is sized to produce the continuous purge flow the chamber requires whilst having a slight overcapacity to replenish a suitably sized storage vessel. The initial chamber higher purge gas flow is provided by this storage vessel, negating the need to size the generation system at the peak flow the initial purge demands.
The Parker nitrogen system can run 24/7 totally uninterrupted for maximum uptime and AM production capacity.
The illustration below details Parker nitrogen generation systems for single and multiple AM machines.
Parker NITROSource and MIDIGAS have been utilised in many additive manufacturing machine applications saving end users literally thousands per annum in gas cost from traditional methods of supply. To learn more, download the brochures for Parker MIDIGAS and NITROSource nitrogen generators.
This blog was contributed by Phil Green, application and training manager, Parker Gas Separation and Filtration Division, EMEA.
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Often nicknamed manufacturing’s fourth utility alongside electricity, gas and water, compressed air is used in over 90% of the world’s manufacturing facilities. As with the other utilities, it is a critical cog in production processes. Its proper application and maintenance have a profound impact on the productivity, financial results and successful operation of businesses.
Facilities and maintenance personnel strive to assure that their compressed air systems operate in a safe, efficient and cost-effective manner. To do this, purification systems are installed to ensure a continuous supply of high quality compressed air, and filtration is at the core of any purification system. Filtration technologies for compressed air treatment use replaceable filter elements that must be changed periodically. However, there is often confusion over why and when the filter element needs to be replaced.
Here, we will examine the types and sources of contamination, filtration technologies and their function, frequently asked questions, myths surrounding differential pressure monitoring, and recommendations for changing filter elements.
Contamination control
Compressed air contamination comes from a variety of sources:
There are 10 contaminants that require treatment in a typical compressed air system:
Coalescing filters are one of the most important types of purification equipment as they treat the majority of these contamination types whilst water separators, dry particulate filters and adsorption filters address the others. The table below shows how each technology is used to ensure clean compressed air.
All of these filter technologies (with the exception of water separators) use a replaceable filter media, typically in a cartridge, or element form. These elements are subject to extreme, dynamic conditions in the compressed air stream, including:
Over time, these conditions lead to the degradation of the filter media and subsequent loss of its contamination removal integrity. Hence, the filter elements should be replaced periodically to assure optimum contamination removal performance.
Parker recommends an annual (12 month) replacement of its coalescing and dry particulate filters and float drains to ensure proper contaminant removal. Parker’s domnick hunter OIL-X coalescing filters and dry particulate filters come with an Air Quality Guarantee that is based upon annual filter change-outs using genuine parts.
While Parker makes a clear statement on maintenance requirements, their remains a great deal of uncertainty on when and why compressed air filter elements should be changed. This is understandable, as every compressed air system is different. However, conditions, even within the same system, can change rapidly, so it is best to adopt a preventative position when it comes to maintenance.
Why should I change my compressed air element?
As discussed above, the effects of the arduous conditions in which coalescing and dry particulate filter elements operate will eventually degrade their performance.
What happens if a filter element gets damaged?
In time, the contaminants will weaken the media and cause leaks or holes to form. Once this happens, their leak area will rapidly grow and contamination will bypass the filter element.
What if my facility only operates part-time. Will I get a much longer life out of the filter elements?
As noted, the filter elements will be affected by the contaminants in the compressed air stream, and this constant exposure will weaken them. To preempt carryover, an annual filter change-out is considered a best practice. Parker guarantees the performance of filters that have annual filter change-outs.
Can I wash filter elements?
No, it is not possible to wash contamination out of the filter media. Subjecting the filter media to hot soapy water or solvent will result in damage.
My filter element doesn't look dirty. Do I need to change it?
First, the part of the filter element you can see is the drainage layer which is responsible for preventing coalesced liquids from being carried downstream. The main filtration media is below this layer and is not visible without dismantling the filter element. Second, coalescing and dry particulate filters capture aerosols and particles down to sub-micron size - undetectable to the human eye.
Myths surrounding differential pressure monitoring
Many filter housings are supplied with differential pressure monitors. It is a common mistake to base filter change-outs on these devices. DP Monitors are non-calibrated and typically indicate a pressure change from the upstream side to the downstream side with a substantial margin of error. While they might give an indication of maintenance required due to a blockage on the filter media, they will not give an accurate depiction of the filter’s ability to remove contamination. Thus, they are not to be relied upon to determine filter element maintenance.
Myth
Differential pressure is an indication of air quality.
Fact
Differential pressure is the result of the filter element collecting contamination, but there is no correlation to the delivered air quality.
Myth
The filter is fitted with a DP Gauge to indicate when to change the filter element.
Fact
These devices offer a general idea of pressure reduction. They are not calibrated and have an accuracy margin of +/- 25%. They should not be relied upon as a service indicator. The manufacturer’s recommendation should be followed instead.
Myth
Compressed Air filter elements should only be changed when differential pressure rises.
Fact
While keeping differential pressure low is a good practice, it does not have a comprehensive impact on contamination carryover. Hence, it should not be used as an indicator of when the element should be changed.
ConclusionFilter elements must be replaced periodically to ensure a continuous supply of high quality compressed air is always available. Other benefits include:
This article was contributed by Mark White, compressed air treatment applications manager, Parker Gas Separation and Filtration Division EMEA
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