Comment from Trevor Holroyd, Kittiwake Holroyd

What are the main advantages of adopting acoustic emission’s AE technology over traditional vibration analysis? (VA)

“With well-defined ISO standards, traditional vibration techniques including vibration monitoring and vibration analysis have provided a trusted approach to condition monitoring for the past thirty years.Yet, it remains a complex science and requires sophisticated knowledge and understanding from a seasoned expert. In contrast, AE technology extends and simplifies the science, placing the power of vibration techniques directly into the hands of every engineer. Signals can be processed at the AE sensor into an easily understandable form.

“Let’s be clear, vibration analysis (VA) as a technique will have a place for many years to come for many end users, however there is no escaping from the fact that there is often a requirement for a costly and unsustainable level of knowledge required to affect a good diagnosis. For VA, the defect repetition frequencies are critically dependent upon the machine component design and geometry, as well as the precise running speed. Vibration can occur independently in X, Y or Z axis and so orientation of the sensor is as important as location. For a detailed interpretation it is also necessary to know the internal machine geometries, shaft speeds, meshing frequencies etc and to analyse the data before making a diagnosis. So, in objective summary, VA is valuable, but too often overly complicated.

“In fact the areas in which vibration and AE both apply can be illustrated as overlapping circles. AE provides an earlier warning detecting wear and small defects, whereas with vibration, damage must have occurred to detect a signal. AE will pick up a lack of lubrication, friction, and cracking, which vibration will not. Although it must be acknowledged that the totality of information obtained from AE will be more limited than that derived from vibration”

Is AE more reliable than VA?

“It’s not more reliable per se, but as it doesn’t require a vibration expert to interpret the results, it could be viewed as more reliable when used by maintenance staff in general.

“AE in no way invalidates traditional vibration techniques, it simply extends the impact way beyond what we’ve been able to achieve to date. The signal processing required by AE is, in itself, not something that can be performed by just anyone; it’s a high frequency signal so the user must have the knowledge to interpret the squiggly line on a stethoscope. But recent developments have enabled this processing at the sensor level. The sensor output can now provide pre-characterised numbers that tell you about the condition of the machine. AE technology has been effectively deskilled, enabling much wider application use.

“Suitable for continuously running machinery as well as machinery operating intermittently, slowly or for short durations, AE allows the user to diagnose problems with machinery at an early stage, carry out maintenance procedures and then monitor the improvement. It provides real time information with early sensitivity to faults and applicability to a wide range of rotational speeds.

” As awareness of the unique capabilities of AE increases, so too does the number of applications that it is suited to – many of which have proven difficult for other forms of condition monitoring to address. For example, the analysis signals, whether from AE sensors or VA accelerometers, requires a sufficiently long period of machine running at constant speed so that a statistically meaningful signal characterisation can be made. But that is where the similarity stops. AE can be effective after around 10 seconds of measurements. For example, the algorithm used to derive the widely used acoustic emission parameters of Distress® and dB Level in the MHC range of products from Kittiwake Holroyd requires a 10 second period of running at an approximately constant speed. Comparing this where Fast Fourier Transform (FFT) based vibration analysis typically needs 60-120 seconds measurement time and tight tolerances on machine speed for an effective signal interpretation.

“In those cases where a hand-held instrument is used for periodic Condition Maintenance (CM), it may be possible to interrupt normal machine operation and put it into a special continuously running mode for the duration of CM measurements. However, such disruption is not always possible and never convenient. Furthermore it is not compatible with the current trend towards CM automation, which require continuous online monitoring with permanently installed sensors inputting CM data or status into SCADA systems or PLC’s. Kittiwake Holroyd’s AE product range includes portable instruments, permanently installed remote sensors for areas of difficult access, as well as stand-alone programmable smart sensors for continuous surveillance.”

From a financial viewpoint are there any benefits associated with AE over VA?

“For vibration techniques to be effective you need equipment that’s far from cheap coupled with clever people to get the best from it. Every result must be analysed to understand what’s good and what’s bad. For those that cannot afford the luxury of in-house vibration experts, there are many vibration specialists who offer a contract monitoring service; again, requiring not insignificant investment. While for some, the criticality of certain applications coupled with the scale of some companies might justify this cost, others could still benefit from the efficiencies realised by similar CM techniques.

“Ultimately, maintenance personnel are responsible for keeping machinery running. If they are empowered to monitor condition themselves, identify where action is needed and then check that the action taken has solved the problem, then deskilled AE technology has significant advantages of cost, speed, flexibility and ease of field application in comparison to traditional vibration analysis techniques. It is the efficient and effective approach to CM.”

Is AE suitable for both land and marine based applications?

“Based on frequencies much higher than are monitored in the repetitive synchronous movement of vibration, AE technique is absolutely suitable for both land and marine based applications. These frequencies are the result of shock, impact, friction and cracking for example. By this means it is possible to detect impending failure before damage occurs, as well as monitoring its progress thereafter.

“AE technology spawned from the aviation industry where vibration analysis simply couldn’t be easily applied, short of a suicidal maintenance technician hanging off the wings. It is specifically designed to allow users with little knowledge of the subject to check bearings and major slideways for condition in a way that would be near impossible using traditional vibration techniques.

“In land based applications throughout industry, AE is favoured by maintenance personnel as a front line technique. Whether food and drinks, manufacturing, utilities or building services, the use of AE allows maintenance staff to quickly assess machine condition, without knowing the bearing’s ISO number, speed, size or history. This allows them to focus maintenance activities when and where they are required with minimum disruption to operations and, most importantly, to check there and then that a repair has been effective.

In a marine setting, vibration analysis is typically undertaken on ships using outside, third party consultants, if at all. With AE technology, you give it to a ship’s engineer right out of the box and by the end of their shift they will have an accurate assessment of all the engine room pumps, turbine and generator bearings, crane slewing rings and any ancillary air leaks in the engine room.”

Trevor Holroyd, managing director, Kittiwake Holroyd

Diesel & Gas Turbine Worldwide, January 2012

Kittiwake Proactive Technologies sponsor National Tribology Conference

The National Tribology Conference 2011 was held at Indian Institute of Technology, Roorkee from Dec 08-10, 2011. It was jointly organised by the Tribology Society of India and Dept. of Mech. Engineering, IIT, Roorkee

Kittiwake Proactive Technologies Ltd. was co-sponsor for this event which was attended by eminent tribologists, academics and industry experts, not only from India but also from as far afield as France and the UK. Deepak Sharma, director Kittiwake Proactive Technologies, presented a paper “Acoustic Emission – A new Condition Monitoring Tool” in the condition monitoring section of this event. This included reference to a paper by Dr Holroyd of Kittiwake Holroyd, Acoustic Emission (AE) experts. The conference was well attended with interesting discussions on the merits of AE compared with traditional Vibration techniques in the condition monitoring field.

National Tribology Conference 2011

Global sales conference takes place at Kittiwake

On the 31st October Kittiwake sales representatives from across the globe arrived at the Kittiwake head office for a week of presentations, discussions and workshops. The conference was overseen by Dr Steve Dye, Business Development Manger at Kittiwake, and was attended by the sales teams from the UK, America, Malaysia, India, & Germany. Delegates from Kittiwake’s recently acquired group companies, Kittiwake Procal & Kittiwake Holroyd were also present and shared their knowledge into the fields of Gas Emissions monitoring & Acoustic Vibration analysis. The agenda covered the current product range including hands-on training, Kittiwake’s target markets, R&D projects as well as future directions.

Seeing disruptive technology as an opportunity – not a threat

Why acoustic emission technology represents the next generation of vibration

History, experience and familiarity count for a lot where condition monitoring is concerned. But that doesn’t negate the need for change, innovation and the advancement of tried, tested and trusted techniques. The late Steve Jobs commented: “Innovation is the ability to see change as an opportunity – not a threat”. Condition Monitoring (CM) is transforming rapidly and so too must the mindset of CM practitioners and users. It’s not good enough to simply disregard a disruptive technology in an effort to protect the “old guard”. When combating downtime, there’s no place or historical sentiment.

Steadily disrupting traditional vibration techniques is acoustic emission (AE). AE technology spawned from the aviation industry where vibration analysis simply couldn’t be easily applied, short of a suicidal maintenance technician hanging off the wings. AE technique is based on frequencies much higher than are monitored in the repetitive synchronous movement of vibration. These frequencies are the result of shock, impact, friction and cracking for example. By this means it is possible to detect impending failure before damage occurs, as well as monitoring its progress thereafter.

With well-defined ISO standards, traditional vibration techniques including vibration monitoring and vibration analysis have provided a trusted approach to condition monitoring for the past thirty years. Yet, it remains a complex science and requires sophisticated knowledge and understanding from a seasoned expert. In contrast, AE technology extends and simplifies the science, placing the power of vibration techniques directly into the hands of every engineer. Signals can be processed at the AE sensor in to an easily understandable form.

Let’s be clear, vibration analysis (VA) as a technique will have a place for many years to come for many end users, however there is no escaping from the fact that there is often a requirement for a costly and unsustainable level of knowledge required to affect a good diagnosis. There is no doubt that VA is valuable, but it is too often overly complicated.

Pull out

  • With AE – signal processing is undertaken automatically at the sensor level.
  • With VA – the signal is processed downstream manually or semi-automatically.
In fact the areas in which vibration and AE both apply can be illustrated as overlapping circles. However, AE provides an earlier warning detecting wear and small defects, whereas with vibration, damage must have occurred to detect a signal. AE will pick up a lack of lubrication, friction, and cracking, which vibration will not. Although it must be acknowledged that the totality of information obtained from AE will be more limited than that derived from vibration.
The signal processing required by AE is, in itself, not something that can be performed by just anyone; it’s a high frequency signal so the user must have the knowledge to interpret the squiggly lines on a stethoscope. But recent developments have enabled this processing at the sensor level. The sensor output can now provide pre-characterised numbers that tell you about the condition of the machine. AE technology has been effectively deskilled, enabling much wider application use.
Suitable for continuously running machinery as well as machinery operating intermittently, slowly or for short durations, AE allows the user to diagnose problems with machinery at an early stage, carry out maintenance procedures and then monitor the improvement. It provides real time information with early sensitivity to faults and applicability to a wide range of rotational speeds.
As awareness of the unique capabilities of AE increases, so too does the number of applications that it is suited to – many of which have proven difficult for other forms of condition monitoring to address.
So why are many CM practitioners being so resistant to the benefits that AE brings to the table? We know that many senior people have invested a lifetime in vibration and are, perhaps, understandably wary of losing power and status. After all, if you ‘dumb down’ vibration, surely this reduces the perceived value that they bring to the organisation?
Actually it doesn’t. Just because they are mature with a proven track record, this in no way invalidates traditional vibration techniques. It simply extends the impact way beyond what we’ve been able to achieve to date.
Whilst for some, the criticality of certain applications coupled with the scale of some companies might just justify the cost of vibration techniques, others could still benefit from the efficiencies realised by similar CM techniques.
Ultimately, maintenance personnel are responsible for keeping machinery running. If they are empowered to monitor condition themselves, identify where action is needed and then check that the action taken has solved the problem, then AE has significant advantages of cost, speed, flexibility and ease of field application in comparison to traditional vibration analysis techniques. It is the efficient and effective approach to CM.
We must start to take a broader, longer-term view, nurturing the technology of a new era. Surely it makes sense to embrace CM techniques that provide for the greatest protection or longest period of warning for potential damage and eventual failure. By ‘deskilling’ technology and with confidence, ultimately enabling them to positively and significantly impact a company’s bottom line. Of course there is room for sentiment in business, but not at the expense of progress.
Martin Lucas, managing director, Kittiwake
Plant Engineering, November 2011

Information proliferation: why it’s so important to cut through the noise on sampling and monitoring.

In 2010, more information was circulated globally than all the accumulated information passed in all previous years. The expediential expansion of the internet, particularly social media sites, has meant that the average internet user visits 59 domains and views 1,050 internet pages each month.

A shipping industry that is increasingly fast-moving – driven by new regulations, security issues, health and safety, the environment and increasingly public scrutiny – has not escaped this trend for greater proliferation and requirement for information. Shipowners and operators could be excused for feeling barraged by information. Nevertheless, finding information is important. Filtering through to the right information is even more important.

Take regulation, for example: whether it is the revised ISO 8217 (2010) on fuel content and quality, MARPOL Annex VI (sulphur emissions), ballast water, maritime security, health and safety, the list is endless. When ships take onboard bunker fuel, regulation is of paramount importance; otherwise the amount of bunker fuel piped onboard could not be assessed, nor contents and quality of the fuel fairly and accurately tested, for example. Moreover, as emissions are increasingly scrutinised by regulators, so an owner / operator needs to understand in detail what the compliance parameters are. Where can testing can take place? What testing facilities and equipment are available? What are the current emissions level requirements? What are the risks in procuring poor quality bunker fuel?

Bunker sampling and monitoring is an example of why it is not only essential to monitor the quality of fuels and protect critical equipment and machinery, but it is also imperative for regulatory compliance and dispute resolution purposes. Along with the monitoring of lubricants and emissions, regulation has meant the risks and rewards of accurate and reliable monitoring data can make a significant dent or improvement upon a ship owner or operator’s bottom line.

Given the increasing relevancy of condition monitoring to the shipping industry, Kittiwake has launched the world’s first marine-focused condition monitoring information portal: https://www.machinerycondition.com. This resource is designed to provide stakeholders with detailed technical information and practical guidance across every aspect of marine condition monitoring, with information continually updated as international rules, regulations, technology and working practices change.

Cutting through the myriad of regulations and compliance issues can be complex. In May 2011, DNV Petroleum Services (DNVPS), the bunker fuel testing company, characterised “off-specification” bunker fuels as the “biggest challenge” in terms of the technical aspect of ship operators’ business during 2010. A DNV report concluded that 94% of 96 respondents coming from the technical, operations and management departments of shipping firms said they encountered problems with bunker fuel deliveries.

Around 50% of the shipping representatives said the “fuel quality cases they encountered were resolved in a satisfactory manner,” although 18% of them did not report a positive outcome. The 18% said the availability of an industry standard on fuel contaminants, technical advice guiding the ship on how to use problematic fuels and de-bunkering, would have been useful.

Additionally, over 90% of the representatives involved in purchasing, listed fuel performance indicators, which include off-specification delivery records and delivery quantities, as the most important considerations when buying bunkers.

Some 14% of the total respondents, meanwhile, said they had to debunker the seriously off-specification fuels they received, while 9% did not have to offload but managed to use the problematic fuels based on advice from fuel management companies.

Much of the challenge for ship-owners and operators procuring bunker fuel is that as the shipping industry moves to cleaner fuels, so the source of that fuel and the resulting content become more fragmented and, in some cases, incompatible. How many owner / operators, know, for example that when the purchase 1.0% Low Sulphur fuel that this fuel has been blended with “cutter stocks” such as marine diesel oil (MDO) that is diluted with Heavy Fuel Oil (HFO). As fuel sources alter and there is increasing demand for multiple emission level bunker fuel, so the cutter stock is less likely to be sourced from the same refinery or region as the HFO it is being blended with, for example.

Global bunker player O.W. Bunker last year urged fuel suppliers to take “greater responsibility” in helping ship-owners overcome the technical difficulties associated with using lower sulphur fuels. It warned some ship-owners and operators had been experiencing problems including loss of propulsion, engine failure, filter blockages and damage to auxiliary pumps. “Switching to low sulphur fuel oils and distillates is complex and there needs to be a deep understanding of the technical process,” Steffen Kortegaard, Technical Director, O.W. Bunker, was reported saying.

This view was recently corroborated by Iain Butterworth, Associate Director of UK-based Myton Law, who reported a rapid increase in cases of main engine failures, citing the rapid increase in engine technology and the engine’s compatibility with a much wider scope of fuel types and quality for the emerging trend.

If the real and potential danger of engine failure and the resulting costs of de-bunkering, as well as the potential litigation claims between owner / operator and bunker supplier were not by now self-evidenced, then INTERTANKO’s recent intervention on the matter underlines its importance.

INTERTANKO’s Technical Director Dragos Rauta explained the thinking behind its latest joint submission with Norway to the IMO, which presents data collected from two testing agencies, indicating that approximately 1.4% of bunkering worldwide was the cause of machinery problems when the ship started using the fuel. Rauta said ship operators faced two categories of problems related to bunkers, namely sulphur content, which can breach MARPOL Annex VI limits, and chemical contamination. Of the two, Rauta said chemical contamination was the most serious issue as it could cause engines to stop, or make operations very difficult.

Bunker sampling is not only essential for monitoring the quality of fuels and protecting critical equipment and machinery; it is also imperative for regulatory compliance and dispute resolution purposes. Testing of bunker fuel can be undertaken on-site or off-site in a dedicated laboratory. The table below indicates the testing possibilities for fuels specified in ISO 8217. Where an off-site test is not specified then the parameter is not covered in ISO 8217 for that grade of fuel.

On-site testing, enabled through Kittiwake’s product range of sampling equipment, for example, allows for an immediate decision to be made in case of an off specification fuel but with a limited number of achievable test parameters.

  • Density
  • Viscosity
  • Water (inc salt / fresh)
  • Pour Point
  • Cloud Point (used by military but infrequently by merchant marine)
  • Compatibility (c.f. sediment)

Off-site testing in a laboratory allows for a much larger number of test parameters to reflect the complete range within the fuel specification ISO 8217.

Understanding the benefits of what both “on site” and “off site” fuel testing provide the ship-owner / operator with offers a good example of how what was once a tick box on a spread sheet for a bunker surveyor has become increasingly complex and vital to the safe and profitable operation of a vessel.

It’s not just bunker fuel content that needs to be monitored. Reducing shipping emissions will be the major driver of change in the maritime industry for decades to come. In the near term, the sulphur limit for fuels burnt in emission control areas (ECAs) will drop from 1.0% to 0.10% in 2015. And since 2010, vessels also need to comply with EC Regulation 2005/33/EC when in EU ports, which, apart from a few exceptions, requires the use of 0.1% sulphur fuel or equivalent emissions. Moreover, legislation pertaining to Nitrogen Oxide (NOx) has already been implemented and, whilst beyond the horizon, legislation around greenhouse gases from either the IMO or the European Union, or both, is imminent.

So ship owners and operators have serious decisions to make and data sets to provide; ultimately based on a complex set of circumstances and a fluid regulatory background. However, there are only two viable options enabling vessels to comply with SOx emissions regulations; use fuel within sulphur limits or fit exhaust after-treatment systems.

Continuous emissions monitoring (CEM) has an important role to play in both, and ‘ in situ’ tools are the most accurate yet. The IMO regulation allows for abatement technology to achieve sulphur emission reductions and, in line with this, Wärtsilä recently predicted a “rapid ramp-up and development of the scrubber market”. Systems capable of measuring down to the equivalent of 0.1% sulphur fuel are key for confirming compliance with SOx regulations when after treatment is used.

With the wide proliferation of ECAs, information on what parameters constitute complicity in what region have become a pre-requisite, as is finding the right information to unravel the complexities of fuel monitoring and testing.

Winston Churchill once said: “True genius resides in the capacity for evaluation of uncertain, hazardous and conflicting information.” If, in 2010, the world communicated more information than ever before, what might we expect from 2011 and years to come? The shipping industry needs information, which in turns leads to knowledge and success. However ensuring the right information is collated, processed and acted upon when so much misinformation abounds, represents just as much of a challenge for shipping as it does everyone else.

Chris Leigh-Jones, Director, Kittiwake 

 

Bunkerspot, July 2011

 

Kittiwake acquires acoustic emission pioneer, Holroyd

Kittiwake Developments, a leading global provider of asset control and protection technology, today announced the acquisition of Holroyd Instruments, a world-leading manufacturer of acoustic emission technology. The newly named Kittiwake Holroyd supplies acoustic emission instruments for the early detection of problems in a wide range of applications, all relating to monitoring the condition of rotating machinery.

Martin Lucas, Managing Director, Kittiwake Developments explained: ” Holroyd’s acoustic emission technology places the power of condition monitoring directly into the hands of every engineer. Traditional vibration analysis has provided a trusted approach to condition monitoring for the past thirty years, but it is a complex science and requires sophisticated knowledge and understanding. Holroyd’s acoustic emission approach to vibration and stress offers a viable alternative, extending and simplifying the science, making it accessible to anyone”.

Providing real time information with early sensitivity to faults and applicability to a wide range of rotational speeds, the acoustic technique is based on the detection of the high frequency component of naturally occurring stress waves. Suitable for continuously running machinery as well as machinery operating intermittently or for short durations, acoustic emission allows the user to diagnose problems with machinery at an early stage, carry out maintenance procedures and then monitor the improvement.

Holroyd’s product range includes portable instruments, permanently installed remote sensors for areas of difficult access, as well as stand-alone programme smart sensors for continuous surveillance. The company has pioneered autonomous signal processing algorithms – for example its Distress® parameter – which remove the need for machine specific interpretations.

Trevor Holroyd, technical director, Kittiwake Holroyd commented: “We know – unequivocally – that Holroyd’s acoustic emission technology is unrivalled. The alliance with Kittiwake provides the infrastructure, global scale and market knowledge to unlock the growth potential that we know is possible, and we have no doubt that the marketplace is hungry for this simple but effective addition to the condition monitoring weapons armoury”.

Lucas concluded: “As the importance of avoiding down time, generating efficiencies and increasing machinery life continues to escalate, Kittiwake is committed to developing technologies that empower the user to make better decisions, faster. By ‘deskilling’ technology we enable informed maintenance decisions to be made quickly and with confidence.

“This latest addition to the Kittiwake product portfolio ensures that we continue to provide out customers with market-leading asset control and protection solutions that directly impact the bottom line. We’re looking forward to working with this dedicated team of specialists, with years of experience in the design, manufacture and development of acoustic emission techniques to provide yet another form of cost effective asset protection for our customers”.

Despite the challenging financial climate, Kittiwake Developments achieved approaching 10% growth last year. This latest announcement follows the recent acquisition of Procal, a provider of in-situ emissions monitoring technology. Kittiwake continues to explore various expansion strategies to achieve ambitious growth plans, with significant announcements expected during the second half of 2011.

Holroyd