Measuring CO2 to optimise bulk storage of food.


Meeting the food requirements of a growing global population is becoming increasingly difficult. Despite the need for additional food, it is estimated that 50-60% of grain is lost after harvesting, at a cost of about $1 trillion per year. (See note 1 below)

One of the major reasons for lost grain is spoilage due to mould or insect infestation during storage.2 To provide a constant supply of grain year-round, after grains are harvested they are often kept in long term storage. Maintaining the quality of stored grain is crucial, both to ensure the quality of the final food products, and to prevent economic losses for farmers.

Edinburgh Sensors GascardNG Sensor

Insects and moulds can grow in stored grain, and their ability to flourish depends on the temperature and moisture of the stored grain. Moulds are the most common cause of grain spoilage and can cause changes in the appearance and quality of stored grains. Some moulds can release toxic chemicals called mycotoxins which can suppress the immune system, reduce nutrient absorption, cause cancer, and even be lethal in high doses. It is therefore crucially important to prevent the presence of mycotoxins in food products.2

Monitoring Stored Grain
Farmers are advised to check their stored grain weekly for signs of spoilage.3 Traditionally, grains are checked visually and by odour. Grain sampling can allow earlier detection of insects and moulds, but these methods can be tedious and time-consuming. Rapid, simple methods are needed for early detection of spoilage and to prevent grain losses.2

When moulds and insects grow, and respire, they produce CO2, moisture and heat. Temperature sensors detect increases in temperature caused by mould growth or insect infestation, therefore indicating the presence of grain spoilage. However, they are not able to detect temperature increases caused by infestation unless the infestation is within a few meters of the sensors. CO2 sensors can detect the CO2 produced by moulds and insects during respiration. As the CO2 gas moves with air currents, CO2 sensors can detect infestations that are located further away from the sensor than temperature sensors. CO2 measurements are therefore an important part of the toolkit needed to monitor stored grain quality.2

Using CO2 Measurements to Detect Spoilage
CO2 monitoring can be used for early detection of spoilage in stored grains, and to monitor the quality of stored grains. Safe grain storage usually results in CO2 concentrations below 600 ppm, while concentrations of 600-1500 ppm indicate the onset of mould growth. CO2 concentrations above 1500 ppm indicate severe infestations and could represent the presence of mycotoxins.4

CO2 measurements can be taken easily, quickly and can detect infestations 3-5 weeks earlier than temperature monitoring. Once spoilage is detected, the manager of the storage facility can address the problem by aerating, turning, or selling the grain. Furthermore, CO2 measurements can aid in deciding which storage structure should be unloaded first.2

Research published by Purdue University and Kansas State University have confirmed that high CO2 levels detected by stationary and portable devices are associated with high levels of spoilage and the presence of mycotoxins.4,5 Furthermore, they compared the ability of temperature sensors and CO2 sensors in a storage unit filled with grain to detect the presence of a simulated ‘hot spot’ created using a water drip to encourage mould growth.

The CO2 concentration in the headspace of the storage unit showed a strong correlation with the temperature at the core of the hot spot, and the CO2 sensors were, therefore, able to detect biological activity. The temperature sensors were not able to detect the mould growth, despite being placed within 0.3-1 m of the hotspot.6

To enable efficient monitoring of grain spoilage accurate, reliable and simple to use CO2 detectors are required. Gascard NG Gas Detector from Edinburgh Sensors provide accurate CO2 measurements along with atmospheric data, enabling grain storage managers to make decisions with confidence.

The Gascard NG Gas Detector uses a proprietary dual wavelength infrared sensor to enable the long term, reliable measurement of CO2 over a wide range of concentrations and in temperatures ranging from 0-45 °C. Measurements are unaffected by humidity (0-95% relative humidity) and the onboard pressure and temperature sensors provide real-time environmental compensation, resulting in the most accurate CO2 concentration readings.

Easy, fast, and accurate CO2 concentration monitoring during grain storage can provide early detection of grain spoilage, resulting in reduced grain losses, higher quality stored grain, and lower mycotoxin levels. CO2 monitoring could save millions of dollars annually in the grain production industry.4


  1. Kumar D, Kalita P, Reducing Postharvest Losses during Storage of Grain Crops to Strengthen Food Security in Developing Countries. Foods 6(1):8, 2017.
  2. Accessed May 25th, 2017.
  3. HGCA Grain storage guide for cereals and oilseeds, third edition, available from: Accessed May 25th, 2017.
  4. Maier DE, Channaiah LH, Martinez-Kawas, A, Lawrence JS, Chaves EV, Coradi PC, Fromme GA, Monitoring carbon dioxide concentration for early detection of spoilage in stored grain. Proceedings of the 10th International Working Conference on Stored Product Protection, 425, 2010.
  5. Maier DE, Hulasare R, Qian B, Armstrong P, Monitoring carbon dioxide levels for early detection of spoilage and pests in stored grain. Proceedings of the 9th International Working Conference on Stored Product Protection PS10-6160, 2006.
  6. Ileleji KE, Maier DE, Bhat C, Woloshuk CP, Detection of a Developing Hot Spot in Stored Corn with a CO2 Sensor. Applied Engineering in Agriculture 22(2):275-289, 2006.


Pre conference conference on Mercury as a Global Pollutant

This is a brief summary of the Press Conference that preceeded the Mercury 2013 conference in Edinburgh (28 July – 2 August 2013 Scotland).

Panel members: Loic Viatte, Swedish Ministry for the Environment, Dr Lesley Sloss, Chair of Mercury 2013 and Principal Environmental Consultant at IEA Clean Coal Centre and Lead – Coal Mercury Partnership area at the UNEP, John Topper, Managing Director, IEA Clean Coal Centre and Managing Director of the GHG Group, Dr David Piper, Deputy Head of the Chemicals Branch of UNEP’s Division of Technology Industry and Economics, Michael Bender, co-coordinator of the Zero Mercury Working Group, Eric Uram, Executive Director of SafeMinds, Prof. K. Clive Thompson, Chief Scientist at ALcontrol Laboratories UK.

The panel discussed the progress of legislation to reduce emissions from coal-fired power stations and Dr Lesley Sloss explained that, whilst mercury-specific legislation may take 5 to 10 years to be implemented in Europe, control technologies which can reduce mercury emissions by around 70% are already being utilised in many countries as part of initiatives to lower emissions for pollutants such as particulates, sulphur dioxide and nitrogen oxides. However, it was suggested that some developing countries and emerging economies may choose to implement these technologies as part of their commitment to the Minamata Convention.

rialtasalbaIn advance of the Press Conference, Paul Wheelhouse, Scottish Government Minister for Environment and Climate Change, issued the following statement:“An international conference of this stature puts Scotland on the world stage and demonstrates the important part we are playing in addressing global issues.
“Sound science, strong evidence and engaged citizens means properly informed choices and effective action on the ground and this is essential if the harmful effects of mercury pollution are to be reduced.
“This event is a key part of the journey to a new legally binding international agreement – and Scotland should take great pride in being at the heart of that process. I’d like to warmly welcome all of the 850 delegates from over 60 countries to Edinburgh and wish them every success as they progress this crucial agenda.”

Discussing the different priorities for the week’s conference, Michael Bender said “Mercury knows no boundaries which is why it has been necessary to develop an international convention.” One of the main sectors facing a mercury emissions reduction requirement is illegal artisanal gold mining, but this is a challenging social issue because gold mining is the sole source of income for many of these miners. Enforcing legislation could have very serious social consequences. In contrast, the coal industry, responsible for around 25% of the global emissions from human activities, around half of that from artisanal gold mining, is easier to regulate so this is often regarded as a more tempting target for guaranteed results.

Michael Bender also referred to the benefits of trade barriers which are beginning to halt the flow of mercury between countries, so there is a need for this trend to continue and for more chain of custody regulations.

The panel explained the need to ‘’think globally, act locally” – to acknowledge that mercury distributes itself around the globe with no respect for national borders but to appreciate that all countries may play their part to clean up their own back yard.

One of the priorities will be to address the mercury issues that are the quickest and easiest to address; the low-hanging fruit. The panel felt that this would be the products that contain mercury; especially in the healthcare sector (thermometers and similar instrumentation) because of its ‘do no harm’ ethos and the increasing availability of alternative methods and instruments.

One of the most important issues in delivering the aims of the Convention is ‘political will’ to drive change. For example, the election of President Obama was seen as a significant moment in the development of the Convention because he had already addressed mercury issues earlier in his political career. David Piper said that the support of the United States was very significant in the development of the Minamata Convention.

Michikazu Iseri from the Kumamoto Daily News in Japan asked the panel if NGOs are likely to be disappointed with the Convention, but Michael Bender from the Zero Mercury Working Group (an international coalition of over 100 NGOs) said that, whilst many of them might have preferred greater rigour in the terms of the convention, the overall reaction was very positive because the Convention combines both a financial mechanism and a compliance mechanism. David Piper agreed, describing the Convention as a ‘giant step forward’ but Lesley Sloss said the challenge now is to flesh the convention out with more ‘what and how’ detail.

The final question referred to the adoption of low energy compact fluorescent lightbulbs (CFLs) that contain a small amount of mercury; whilst helping to lower energy usage, they contribute to mercury emissions. Responding, David Piper said that he did not expect this to become a significant issue since these technologies are likely to be replaced with even more environmentally friendly options in the near future.

Engineers torque technology to medics


Medical experts and sports scientists are becoming increasingly reliant on engineers as their disciplines become more and more technical. Mark Ingham looks at some of the projects his company, Sensor Technology, has helped behind the scenes.

Like most rugby players I took my knees for granted until the day a twisting fall resulted in a torn anterior cruciate ligament. Fortunately these days it can be fixed with surgery and nine months of physiotherapy, but I took some comfort in the fact that Sensor Technology has contributed – modestly – to the medical knowledge of this crucial joint.

With the pending London Olympics fuelling increased participation in sport, military personnel returning from active service with knee problems and the wear on tear on joints as people live longer the need for new knowledge is growing.

One research programme used a the TorqSense industrial sensor to analyse the performance of implanted replacement knee joints. To do this Sensor Technology helped develop a rig centred on a 100Nm TorqSense transducer with an extended through-shaft supporting crank arms on both ends.

The researchers very carefully align the axis of the TorqSense with the patient’s knee and attach the ankle to the end of one crank. They can then use the other crank to move the knee without the patient having to put in any muscular effort, thus isolating the joint. Data collected from the TorqSense during a test sequence builds up a profile of the knee’s performance.

TorqSense is a surface acoustic wave (SAW) based device. In a TorqSense transducer, surface waves are produced by passing an alternating voltage across the terminals of two interleaved comb-shaped arrays, laid onto one end of a piezoelectric substrate. A receiving array at the other end of the transducer converts the wave into an electric signal. The frequency is dependent upon the spacing of the teeth in the array and as the direction of wave propagation is at right angles to the teeth, any change in its length alters the spacing of the teeth and hence the operating frequency. Tension in the transducer reduces the operating frequency while compression increases it. To measure the torque in a rotating shaft, two saw sensors are bonded to a shaft at 45deg to the axis of rotation. When the shaft is subjected to torque, a signal is produced which is transmitted to a stationary pick up via a capacitive couple comprising two discs, one of which rotates with the shaft, the other being static.

Drug protection
Errors in drug delivery are being reduced year-on-year in all branches of medicine, due to advances in infusion and monitoring technologies.

Most medical pumps are driven by stepper motors, which can be tested by driving them against a DC motor acting as a brake. In one programme we were involved with a TorqSense was mounted between the two motors to record the instantaneous shaft torque during test sequences. These data were then analysed and a model of the motor’s characteristics built up.

The alternative would be to use a very expensive dynamometer, which would also be slower to set up because it would need hardwiring instead of a radio link.

Another drug protection related project was based on the observation that when using diagnostic fluids on ill or nervous patients, hospital staff are likely to be feeling the stress and will not take kindly to bottle tops that prove difficult to open. However they will want the tops to feel secure enough that they can be confident of the fluid’s sterility. Thus tightening bottle caps in pharmaceutical plants is a precision operation

To this end Sensor Technology has helped develop specialist capping machines, which not only tighten bottle caps within precisely defined tolerance but also log every detail of every bottle. The machines are essentially simple: filled bottles are presented to a torque head, which quickly screws on a cap to a target torque.

However a batch size is typically 10,000 bottles, and they will have to be capped at say one per second. Every cap will have to hit target tightness, with the measurement logged for traceability. Sterility will be paramount, so the machine will probably operate in a high vacuum chamber to ensure that no bacteria or other contaminants are present.

TorqSense met all criteria for this application, it being simple, robustness, high speed and wireless. Basically TorqSense could be used ‘as is’; with a suitable mounting arrangements. Similarly, the associated software was ready to go after a bit of calibration and the addition of some bespoke front end graphics.

The software was required to do two things: run the torque up to 10kgcm within tolerances of 10 percent, and record the actual value achieved. This secures the cap to the bottle at a level of tightness that will ensure security and sterility, yet is at a level that can be opened relatively easily by an adult. The logged values are saved to a hard drive to provide a permanent record for traceability.

Diagnostic fluids are distributed widely, typically to every hospital in the country plus many overseas. But they may be stored for months before use. Tracing each bottle’s origin would be practically impossible without full records being automatically produced and saved to a central location.

Sensor Technology helped provide a solution to this complex but critical problem using an out of the box technology.

Wheelchair reliability
In a more conventional engineering environment a TorqSense is helping ensure the reliability of powered wheelchairs, having been incorporated into a dynamometer rolling road built by PG Drives in Dorset.
The rolling road measures the torque between the motor under test and the inertia network it is driving, which is simulated by selective use of both passive and active loads. The TorqSense constantly measures the test motor’s torque at its output shaft, logging it for later analysis.

Prolonged and arduous tests are often run, simulating on and off road, every type of surface, steep gradients, gentle gradients, all sorts of extreme weather, heavy loads, shock loads and every other anomalous behaviour you can imagine.

Before the rolling road was built, the analysis regime was based on test driving around the town, but consistency and repeatability were, of course, impossible to achieve. The rolling road has been used constantly since it was built, so its reliability and ease of use are major issues, both of which are helped by the TorqSense.

As development engineers, we at Sensor Technology never know what our next job will be. But it is heartening to think that we are making such a direct contribution to healthcare and medicine.

Water replaces coal in bringing prosperity to Cardiff!

Water quality has been a central theme in a redevelopment project that began with the creation of the Cardiff Bay Development Corporation in April 1987. This article examines the role that water quality has played in the remarkable transformation that has taken place in Cardiff and explain how monitoring technology has developed to the stage whereby any person, anywhere in the world, can view live water quality data at multiple locations in the Cardiff Bay via the YSI EcoNet web-based system.

Cardiff owes much of its history to the Industrial Revolution of the 1790’s, which stimulated mining in the valleys of South Wales. By the 1880’s, Cardiff had transformed from one of the smallest towns in Wales to the largest and its port was handling more coal than any other port in the world.

On the eve of the First World War in 1913, coal exports reached their peak at over 13 million tonnes.  However, following the Second World War, demand for coal declined and international markets were lost as other countries developed their own steel industries. Trade was increasingly lost to container ports and by the 1960’s coal exports had virtually ceased.

Peter Gough from the British Environment Agency was a student in Cardiff University during the 1970’s and remembers the poor state of the local rivers: “The Taff was as black as coal and incapable of supporting most aquatic life.  At its worst, in the 19th century there were reports of livestock dying after drinking from the river.”

By the early 1980’s Cardiff Bay had become a neglected wasteland of derelict docks and mudflats. Much of Cardiff’s population suffered from social exclusion with above average levels of unemployment.

The regeneration of Cardiff Bay was undertaken to create a complementary mix of housing, open space, commerce, leisure and industrial development. The project also included the construction of a barrage across the mouth of the bay to create a 200-hectare freshwater lake, fed by the rivers Taff and Ely, which would link all of the proposed developments and provide both aesthetic and recreational benefits.

Environmental considerations were extremely important in the proposed redevelopment plan and water quality protection measures were defined in the Cardiff Bay Barrage Act 1993, which stipulated that water quality objectives shall have regard to:
(i) the recreational or other purposes for which use of the water is permitted by the Development Corporation, and
(ii) the needs of the fish in the water and of migratory fish passing to or from it.

Water quality was required to meet the relevant standard as specified by the National Rivers Authority (now the Environment Agency of England and Wales). This standard was the maintenance of a minimum dissolved oxygen (DO) level of 5mg/litre. Peter Gough explains: “When the construction of a barrage was first proposed, concerns were raised for the ecological recovery of the catchment. Cardiff Bay had a huge tidal exchange which resulted in significant pollutant dispersal and a barrage would clearly prevent that and represent a risk to water quality in the future impoundment.

“One of the main concerns was the potential effect of the barrage on migratory fish such as salmon and sea trout, which were starting the process of recolonisation in the 1980s.  They are very sensitive to pollution and to low DO levels in particular. A range of mitigation measures were therefore built into the proposed development plan.”

Construction of the barrage took place between 1994 and 2000 at a total cost of £220million, and in 2000 Cardiff Council took over from the Cardiff Bay Development Corporation and through the Cardiff Harbour Authority (CHA) established five main objectives:

      1. Maintaining the best environmental standards
      2. Improving access to and around the Bay
      3. Developing water use
      4. Increasing the quality and range of facilities
      5. Liaising with communities, commercial businesses and other organisations

Environmental issues
The main issues of concern for the CHA are debris management, flood defence, migratory fish, algae, birds, groundwater levels, problematic species and of course water quality.

Prior to the creation of the barrage, debris (typically 1000 tonnes/annum), which was mostly derived from the two rivers that fed the bay, would have been washed into the Severn Estuary. However, CHA now employs booms to collect debris for transfer to controlled areas.

Flood control has also improved with the barrage. In the past, heavy rain in combination with heavy rivers and a Spring tide would have resulted in flooding. However, CHA is now able to closely monitor and control water levels in the bay with the barrier’s sluice gates. For example, in 2001 a 1:57 year rainfall event resulted in a bay water level rise of just 20cm.

Migratory fish were referred to specifically in the requirements of the Act mentioned above, so the barrage was constructed to incorporate a fish pass to allow migratory salmon and sea trout to return to the rivers Taff and Ely to spawn. In addition, young salmon have been released into the rivers, firstly as part of an impact monitoring programme, and latterly as a mitigation measure. The bay now supports healthy populations of freshwater fish such as barbel, chub, dace, gudgeon, roach and rudd, and Peter Gough reports an improving salmon, trout and grayling population in the two main rivers and their tributaries. He says, “The fish pass incorporates a counter so we have been able to measure the success of the joint activities with the CHA. The focus on migratory fish has proved to be an elegant way to protect and report water quality because most people understand that if salmon can live in a river, the water quality must be good.”

A further stipulation of the Act related to potential effects on local properties from changing groundwater levels. Groundwater surveys were therefore undertaken before the construction of the barrage and have continued ever since.

Invasive species represent a threat to the ecology of the bay and zebra mussels are currently the most significant. Capable of rapidly colonising any structure within a water body, zebra mussels can become a significant problem as they adhere to the surfaces of boats, jetties, anchors, chains, pipes etc. As filter feeders, each zebra mussel typically filters up to 2 litres/day and David Hall from CHA believes that the biomass is so large that the entire volume of the bay could pass though a zebra mussel every two weeks. As a result of this filtration, the water is very clear and David says “This means that cormorants find it easier to prey on fish that swim near the surface, so the balance of fish species has moved in favour of bottom feeders.”

Water Quality
Salmon are unable to survive in low DO water and this was undoubtedly a factor in choosing DO as the main indicator of water quality. However a wide range of other water quality parameters are also monitored.

DO levels are affected by a number of different factors. For example, windy weather helps to aerate the water and cold water is able to ‘hold’ higher levels of DO than warm. As a result, warm windless summer days pose the greatest threat. However, pollution discharges such as combined sewer overflows can also reduce DO levels. Algae have the potential to lower DO levels following death and eutrophication, but David Hall believes that algae in Cardiff Bay, on balance, have a positive effect on DO as a result of photosynthesis.

CHA employs two methods with which to combat low DO levels. An aeration system extends across the floor of the bay and provides an opportunity to circulate and aerate the water. This system is fed by air compressors which feed over 600 diffusers through a network of 20km of pipes. However, in extremely low DO conditions, CHA is able to deploy an oxygen barge which feeds pure oxygen directly into the worst affected water.

YSI multiparameter water quality monitoring sondes have been deployed in Cardiff Bay since the beginning of barrage construction. Initially, these were strategically placed logging instruments from which data was collected manually at regular intervals, but as CHA’s Steve Ellery explains: “This was labour intensive and only provided a historical view of water quality, which meant that our ability to respond to poor water quality was limited and often delayed. We therefore installed 6 YSI buoys in 2000 and began to collect data via radio.”

The radio telemetry provided CHA staff with access to live data which transformed their ability to respond quickly to low DO. However, the radio systems had to contend with interference and line of sight issues, so in 2008, the buoys were connected to YSI’s EcoNet system, which automatically publishes live data to a dedicated website.

A map showing the location of the YSI buoys is shown on the home page of YSI Hydrodata  and provides any web user with access to live water quality data. This data is collected at 15 minute intervals from the buoys via GSM and stored on a secure server that hosts the web data.

Two of the buoys are fitted with water quality monitoring sondes at both 1m below the surface level and also at 1m above the floor of the bay. The remaining seven buoys have one sonde monitoring at 1m below the surface.

YSI sondes are compact, rugged battery powered instruments capable of logging data from a broad selection of sensors that have been designed specifically to withstand the most harsh aquatic environments. The sondes in Cardiff Bay are fitted with sensors for DO, pH, conductivity, salinity, temperature and turbidity, but many other sensor options are possible.

Commenting on the reliability of the sondes, Steve Ellery says: “We have been delighted with the performance of the YSI 6-series sondes because they have enabled us to demonstrate extremely high levels of compliance with the DO requirement. The initial sondes were replaced after about six/seven years and we now run eight spare sondes so that when recalibration is due we can simply swap sondes without incurring any downtime in data collection.

The ability of the monitoring network to deliver live data means that we are able to respond to low DO levels very quickly and accurately, and as a result, over the last five years our compliance performance with the 5 mg/l DO has been over 99.9% every year.”

Users of the YSI EcoNet system do not always opt for live web data display but Steve Ellery has never regretted the decision to do so. He says, “If the sondes were less reliable we would not wish to display inaccurate data, but since their performance has been so good, it has been great to be able to provide the data to anybody with an interest.”

In addition to the buoy based monitoring network, CHA also takes monthly water samples from six locations for the laboratory analysis of a wide variety of parameters including phosphate, nitrate, ammonia, BOD and bacteria.


Looking back over the changes that have taken place in water quality in recent decades, Peter Gough believes that the Taff may be the only capital city river in Europe with salmon spawning within the city and says, “This is testament to what has been achieved in a relatively short period of time.”

The YSI water quality monitoring network has enabled the CHA to provide live data to the public and to ensure the protection of water quality in the bay. This has ensured that the area has become an attractive environment for all forms of life including human beings.

David Hall has lived in Cardiff for the whole of his life and believes that the protection of water quality has been key to the success that the city has enjoyed in recent years. He says, “If you include the housing, pubs, restaurants, sports facilities etc., the development of the Cardiff Bay area represents a total investment of about £2 Billion.

“The overwhelming success of this area hinges on the aesthetic quality of the bay; the water is clean, wildlife is thriving and many thousands of people enjoy a wide variety of leisure activities. Prosperity has once more returned to Cardiff, and this time, it’s not coal we have to thank… it’s water.”

Putting feeling into drugs safety and handling


Most applications we cover on the Read-out Signpost have to do with the actual production of product, say in a pharmaceutical process. However the products eventually end up in the hands of health professionals or patients and the correct handling of these in this area can be as important as in the earlier period of production. This application is one designed to help at this user interface.

When product integrity is paramount, packaging has a key role to play. It has to be secure enough for protection in all likely scenarios, but has to be easy to open in possibly high tension situations.

When using diagnostic fluids on ill or nervous patients, hospital staff are likely to be feeling the stress and will not take kindly to bottle tops that proves difficult to open. However they will want them to feel secure enough that they can be confident of the fluid’s sterility.

To this end specialist capping machines have been developed by Cap Coder, which not only tighten bottle caps within precisely defined tolerance but also log every detail of every bottle that is capped by one of their machines. And they have done it with a minimum of fuss, using an off-the-shelf technology and associated software.

“Our machines are essentially simple,” says Roger Brown of Cap Coder. “Filled bottles are presented to a torque head, which quickly screws on a cap. But the devil is in the details.

“A batch size is typically 10,000 bottles, which we have to cap at say one per second. Every cap has to be done up to the same torque, and we have to provide proof of this performance. Sterility has to be ensured – the machine may even be working in a high vacuum to ensure that no bacteria or other contaminants are present.

“Put all of this together and you end up with a need for a highly engineered machine.”

As the need for traceability emerged, Cap Coder realised that it would have to develop a standard solution, which while not quite identical for every machine, would be based on the same technology deployed in the same way. And because exports are the lifeblood of such an OEM, flexibility to meet different counties’ standards had to be designed in from the outset.

Even the largest bottle tops are not that big, so handling them at the speeds required can appear impossibly fiddly.

“Our philosophy is to have a simply machine design that avoids extraneous parts,” says Roger. “This lead us to the idea that we’d like the torque sensor to be wireless.”

Looking at torque sensors available on the market, one, TorqSense from Sensor Technology, stood out as meeting all criteria: simplicity, robustness, high speed and wireless. The company was contacted and design meetings set up.

Mark Ingham of Sensor Technology takes up the story: “Basically we could use TorqSense ‘as is’ for this application; we just needed to work out mounting arrangements. Similarly, the associated software was ready to go after a bit of calibration and some front end graphics.”

The sensors that attracted the attention of Cap Coder depend for their operation on surface acoustic wave (SAW) transducers. These transducers comprise two thin metal electrodes, in the form of interlocking “fingers”, on a piezoelectric substrate such as quartz. When an RF signal of the correct frequency is applied to the transducer, surface acoustic waves are set up, and the transducer behaves as a resonant circuit.

The key feature, however, is that if the substrate is deformed, the resonant frequency changes. When the transducer is attached to a motor drive shaft, the deformation of the substrate and hence the change in resonant frequency is related to the torque applied to the shaft. In other words, the transducer, in effect, becomes a frequency-dependent strain gauge.

Since the transducers operate at radio frequencies, it is easy to couple signals to them wirelessly. Hence, TorqSense sensors that incorporate the SAW transducer technology can be used on rotating shafts, and can provide data continuously without the need for the inherently unreliable brushes and slip rings that are often found in traditional torque measurement systems.

With the Cap Coder project, software was required to do two things: run the torque up to 10kgcm within tolerances of 10 percent, and record the actual value achieved. This secures the cap to the bottle at a level of tightness that will ensure security and sterility, yet is at a level that can be opened relatively easily by an adult. The logged values are saved to a hard drive to provide a permanent record for traceability purposes.

Roger explains: “Diagnostic fluids are distributed widely, typically to every hospital in the country, where they may be stored for months before use. Tracing each bottle’s origin would be practically impossible without full records being automatically produced and saved to a central location.

“We found a solution to this complex but critical problem using an out of the box technology. And what amazes me is the diversity of other fields in which TorqSense is used – its really any machine with a rotating shaft.”

Plant maintenance and safety


Worker health and safety threatened by plant maintenance failures
Europe-wide safe maintenance campaign officially launched

Dr Jukka Takala

Launching the Campaign at the European Commission’s headquarters in Brussels, Dr Jukka Takala, Director of EU-OSHA, alongside the EU Commissioner for Employment, Social Affairs and Inclusion, Mr László Andor, outlined the campaign’s objectives and the basic rules for safe maintenance as a key contribution to healthy workplaces.
Mr Andor giving his backing to the Campaign, said: “Maintenance is a daily part of every workplace and sector. The 20% of accidents currently linked to maintenance is too high and shows it’s an area where we have to raise awareness and step up our efforts”. He added: “Our overall strategy is to cut work-related accidents in the EU by 25% over the coming years. This campaign will help to raise awareness about maintenance-related risks, saving lives across Europe and bringing us closer to our overall goal for safer and healthier workplaces”.

The European Agency for Safety and Health at Work (EU-OSHA) has launched its new Healthy Workplaces Campaign for 2010/11, promoting safe maintenance across Europe. In some European countries as much as 20% of all workplace accidents are connected with maintenance and in a number of sectors over half of all accidents are maintenance-related.

A Challenge to  industry – do you know whether your maintenance is being carried out properly?
Good plant maintenance is essential to prevent workplace risks, but can be itself a high risk activity for the workers that carry it out.

It is estimated that in Europe 10-15% of fatal accidents at work can be attributed to poorly executed maintenance operations. It is vital therefore, that maintenance is carried out properly, taking into consideration workers’ safety and health. To do this, companies need to understand and measure their Maintenance and Asset Management Performance.

MCP’s AMIS auditing and benchmarking service has been used by over 4000 sites worldwide to measure maintenance performance, taking into account areas such as:

>      Equipment Condition

>      Workload Planning and Control

>      Productivity and Maintenance Effectiveness

>      Training and Safety

>      Motivation, Culture and People Management.

The AMIS programme assesses your systems and procedures, in particularly your Health, Safety and Environment process to ensure Best Practice in Health and Safety.

At a company level, the Board of Directors is required to demonstrate their responsibility for the assets and ensure a safe working environment, commensurate with generating the required return on investment.  The AMIS best practice programme helps companies meet these requirements by:

>      Defining consistent ways of working

>      Ensuring a process for effective management providing the basis for driving increased return on investment

>      Providing a link and support framework for effective Lean Manufacturing application.

Do you know whether your workforce is competent and sufficiently trained to maintain and operate your equipment?
Achieving the highest standard in equipment maintenance is all well and good, but even well maintained machines can still be hazardous to a badly trained operator and it goes without saying that competent technicians and operators are a prerequisite for good business.

Competence is linked to safety and plant efficiency.  Section 2 of the British Health and Safety at Work Act requires all employers `to ensure, so far as is reasonably practicable, the health, safety and welfare of all his/her employees’.  Section 3 extends this to non employees. (See British Health and Safety Executive site.)

In order to do this, an employer must understand the legal duties facing him/her, and keep up to date with any changes.  Section 2 also requires employers `to provide such information, instruction, training and supervision as is necessary to ensure, so far as reasonably practicable the H & S at work of all employees.’

The IMechE published an article in April 09 on the need for managers to protect themselves with respect to corporate manslaughter, with more cases now being brought against individuals.  If there is not enough evidence for a corporate manslaughter charge, the HSE focuses on getting a conviction under section 37 of HSW Act which applies to individuals.

MCP has researched over 350 companies to understand their approach to maintenance related training, and their findings show that many organisations still have some way to go to improve performance in the provision of effective training.

To ensure safe and productive operation of equipment requires operators to be fully competent in the operation of the equipment.  All too often training is based on the ‘watch Nelly approach’ or initial training is not followed up with checks to ensure the standard operating procedures are being adhered. It is also a common practice to transfer operators to equipment on which they have not being trained when staff shortages occur.

MCP’s Research highlights include:

>      Only 16% of companies have provided their staff with formal training in maintenance management techniques.

>      Only 18% of companies reported that all their plant operators were fully trained and competent to operate the production equipment.

Adopting a structured approach to training that provides the right training at the right time can not only prevent safety risks, it can also improve equipment performance and plant efficiency.

Poorly managed maintenance activities and procedures raise the risks of workplace accidents, including fatal accidents, involving workers at all levels across a wide range of industries. In one of the worst incidents of its kind in Europe, the Piper Alpha disaster of 1988 saw the North Sea oil and gas platform turned into a blazing inferno within seconds, killing 167 workers – a tragic example of the potential consequences of inadequate maintenance procedures.



Nitrate problems are soluble – but who pays?

The world needs to double food production by 2050 but the use of Nitrate fertilisers, which dramatically increase crop yield, has resulted in heavy nutrient loads in surface and groundwater. This leads to algal blooms and eutrophication which can result in the death of fish and invertebrates. In addition to the damage caused to aquatic environments, water companies have to spend a lot of money treating drinking water to reduce nitrates to acceptable levels.
This article summarises the results of an EC LIFE Environment funded project NITRABAR in which researchers from the University of Strathclyde and its partners have demonstrated a technique which reduces nitrates by over 90%.
A large number of Europe’s rivers will need NITRABAR, so the next step is to figure out who pays?

In a news story covered in the Read-out Signpost news section (31 July 2009) on Quantitech’s FTIR analyser we came across a reference to an EU funded programme called NITRABAR.

Nitrate pollution in rivers, lakes, reservoirs and underground aquifers is a major problem. However, researchers from Belgium, Malta, Poland, and Britain have developed a new low cost, environmentally friendly technology, known as ‘NITRABAR‘ which substantially removes nitrate from groundwater. The project is an EC LIFE Environment Project that demonstrates the remediation of agricultural diffuse NITRAte polluted waters through the implementation of a permeable reactive BARrier.

Algal blooms have become an unfortunate feature of many water systems. In extreme cases, oxygen depletion results in the death of invertebrates and fish.

The NITRABAR system, designed by Prof. Robert Kalin, Professor of Environmental Engineering for Sustainability, Head of Department, Civil Engineering and Director of Research, David Livingstone Center for Sustainability at the University of Strathclyde (GB), consists of a trench containing a mixture of natural materials which form a permeable reactive barrier that removes nitrate from shallow groundwater immediately before it enters rivers or lakes.

A key feature of the NITRABAR system is its ability to convert dissolved Nitrates in the groundwater to harmless Nitrogen gas through the action of bacteria.

A team of experts, led by Professor Kalin, has been collecting monitoring data at a trial site in Ballymena, N. Ireland since early 2008 and results indicate that nitrate is being effectively removed within the barrier, with concentrations at the inlet being reduced by over 90%.

Now that the science has been proven and the environmental and financial benefits have been calculated, the only outstanding issue is funding.

Milk pressure


Pressure Monitoring in Milk Production

The Nestlé research and development centre in Konolfingen, Switzerland, is developing milk-based constitutional food products. The pressure monitoring at the heat exchangers in the new testing facility is conducted by Baumer pressure transmitters, which are equipped with hygienic CombiConnect process connections made of stainless steel.

Nestle Products

Nestle Products

In Konolfingen, the international nutrition company Nestlé operates the Nestlé Product Technology Centre (PTC) – one of 24 research centres worldwide. For more than 30 years, the company has been developing milk-based products and the respective production processes there, with the main focus lying on infant food, special diet nutrition and health care food. The Konolfingen developers are researching appropriate recipes and testing processes for all operational Nestlé companies worldwide requiring new products for these areas.

Heat Exchangers in the New Testing Facility
For hygienic reasons, all measuring devices in their new testing facilities had to be equipped with an aseptic screw connection according to DIN 11864-1. All over the PTC, pressure transmitters of the ED701 series were already being used in various other applications such as homogenisers, mills and filling equipment. Since Nestlé had been very satisfied with those devices, they were also chosen for the pressure measurement at the new facility’s heat exchangers. Depending on the processes to be tested, up to six heat exchangers are used for heating and/or cooling the products, with the temperatures going up to 150°C.

At high temperatures, the products precipitate protein, which then sediments at the heat exchanger’s metal plates. If there is too much sediment on the exchanging face, the differential pressure between the product and medium side rises and the heat exchangers have to be cleaned. With this application, the PTC developers test the recipes and manufacturing processes with different kinds of liquid products ranging from milk to dessert crème. Among other results, the tests show the possible range of process temperatures between medium and product as well as the time period the production can run without the heat exchanger needing to be cleaned.

Differential Pressure Measurement with the ED701
The differential pressure is measured by the ED701, a piezo-resistive pressure transmitter with a stainless steel diaphragm for industrial and hygienic applications. It is based on a silicon sensor designed for high precision within the widest possible range of temperature. Its downstream digital compensation reduces the signal drift. The piezo-resistive silicon sensor is anodically bonded to a very stable glass base attached to a stainless steel construction, which guarantees an excellent thermal isolation. A stainless steel diaphragm and a specially processed filling liquid isolate the sensor from the process medium.

The electronics are located within the hermetically sealed transmitter housing, making the ED 701 extremely resistant to humidity, shock and vibration. Depending on the choice of the electrical connection, the protection classes vary from IP 65 to IP 67. The electronics’ core piece is a micro-controller compensating any drift effects on the sensor signal due to temperature changes. Therefore, these effects can be eliminated over a wide range of temperatures with a short response time.

The ED 701 is available with a great variety of pressure and electrical connections, a 4…20 mA current loop and various voltage output signals. The line’s most distinctive features are its short response time (max. 5 ms) and an excellent repeatability and long-term stability. The hygienic design makes the ED 701 series most suitable for applications in the food and beverage processing industry as well as in the pharmaceutical and biotechnology industry. Any parts contacting the media are made of stainless steel 316L / 1.4435 and all materials, including the white oil used as standard filling liquid, are compliant with the FDA standards.

For the use in the heat exchangers, the pressure transmitters were constructed with an accuracy of 0.4% FS and a compensated temperature range of -10 to 125°C (on the cooling water side) respectively a high medium temperature of 300°C maximum (on the heating side). The measuring range of the gauge pressure covers 0 to 20 bar.

Connection for the Milk Tube Fitting
Since a new process connection was also required for the new milk tube, the Nestlé PTC developed a special adapter for the ED701 in co-operation with Baumer.

CombiConnect connections

CombiConnect connections

Whereas Baumer delivered the connection for the pressure-receiving side, the matching part on the product side was constructed by Nestlé. “For the milk tube fitting, Baumer offered us the CombiConnect adapter, which we found most suitable thanks to its flush-mounted O-ring”, says Ernst Strahm, measurement technologist at the Nestlé PTC in Konolfingen. The CombiConnect system provides a series of hygienic, replaceable process connections made of acid-proof stainless steel. Since they can be used with the pressure transmitters FlexBar and ED701 as well as the temperature measuring device CombiTemp, they offer a high flexibility. The connections were developed according to the demands of the food industry fulfilling the FDA and EHEDG criteria.

A further challenge this application posed was the very small pipe with a diameter of only 10mm, making it very difficult to clean. The problem was solved by choosing a high flow rate and a pressure transmitter with a small volume compared to that of the tube.

Decision Criteria
The Nestlé product developers had already been convinced by the reliability of the pressure transmitters used in various other applications. Concerning the heat exchanger applications in the new testing facilities, all upcoming challenges were mastered thanks to the flexible CombiConnect connections and a close collaboration with the manufacturer in developing an adapter. “For a hygienic pressure measurement, the quality of the measuring devices is the decisive criterion. With the ED701, we have had consistently good experiences”, resumes Strahm.

Laboratory efficiency


TOC analyser improves lab efficiency

Leading instrumentation company HACH LANGE is helping a number of key customers save valuable time and costs with its new IL550 TOC-TN analyser.

TOC analysis is vitally important in applications ranging from power generation, wastewater, drinking water, surface water and ultrapure water, to agricultural soils, contaminated land and food. These analysers therefore offer a range of options designed to meet every need.

A typical analysis for total organic carbon (TOC) measures both the total carbon present as well as the inorganic carbon. This method has traditionally been the preferred analytical technique to measure water quality during the purification process.

COD (Chemical Oxygen Demand) is the total measurement of all chemicals in the water that can be oxidised. BOD (Biochemical Oxygen Demand) is a longer method designed to measure the amount of material (or organic carbons) that bacteria can oxidise.
Although closely related to both BOD and COD analysis, TOC is important in its own right because it is the sole analytical method able to quantify only those species that contain carbon. For this reason TOC is a parameter that is required by regulations in many industries, for example, as a waste acceptance criterion of hazardous waste TOC analysis is now compulsory. It also provides a number of key benefits over BOD and COD including a significantly improved analysis speed and higher accuracy.

The IL550 can also be used for the determination of dissolved organic carbon (DOC) as well as total organic carbon (TOC) in sewage, river, landfill leachates, effluents and groundwater samples. Subsequently, it has proved to be an important addition for HACH LANGE customers including Britin’s Environment Agency’s National Laboratory Services (NLS), South West Water and laboratory testing services company Chemtest.

At the NLS, much of the analytical work is for regulatory purposes, so it is vitally important that fast, accurate, reliable results are produced. Richard Yates, Inorganic Analysis Team Leader at the NLS, said: “The high calibration range of the IL550 reduces the number of over-range repeat analyses we have to perform, thereby saving valuable lab time and improving the sampling process. In addition, the instrument is very easy to use and meets our required limit of detection.”

Tracy Churchill, Senior Assistant Scientist for South West Water, also praised the benefits of the IL500. She explained: “The IL 550 software is very user-friendly, making it easy to train analysts. Additionally, and most importantly, because the analyser has a ‘stand-by’ mode we are able to leave the instrument on at a reduced temperature, which prolongs the life of the catalyst. As a result of these features we have significantly reduced downtime and maintenance costs, because previously we had to replace the catalyst on a fairly regular basis. We are delighted with the TOC-TN analyser and the results it is producing.”

The IL550 has also helped Chemtest save significant time and costs over the past year. Laboratory manager Darrell Hall said: “We have found the IL550 more reliable than the previous methods we used for TOC analysis on water and leachates samples and in general it has made the lab analysis process much more efficient.”

A key feature of the IL550 is particle tolerance in liquids. The autosampler needle has a large internal diameter and the sample is injected directly via the pneumatic port into the furnace – this eliminates blockages, cross-contamination or leaks because there is no septum or valve. This also removes the need to filter waste water samples because the IL550 measures the TOC of both liquid and solid particulates in a sample. Samples are also stirred prior to injection to ensure homogeneity.

With the IL550, digestion takes place at up to 950 Deg C and the solids module is able to increase the temperature to an unrivalled 1300 Deg C. The UV version is equipped with a high-energy UV lamp, which offers the advantage of direct contact with the sample.
In summary, Matthew Dillon, lab sales manager at HACH LANGE says, “The key feature of the IL550, that sets it apart from other instruments, is its ability to provide highly accurate results for a wide range of sample types and we are delighted that so many of our customers have benefitted from the efficiencies that the instrument delivers.”

AN1H1 again?


Measuring Body Temperature from a Distance to Prevent Spreading of AN1H1 (“Swine Flue”)

Xenics, leading developer of innovative infrared detection solutions for a wide range of applications headquartered in Europe, presents a secure and non-invasive countermeasure to the uncontrolled spreading of the respiratory disease, sometimes called swine flue, caused by the potentially pandemic virus AN1H1. Easily installed and operated at airports and border stations, Xenics offers the new Raven, an uncooled microbolometer infrared camera, which measures, from a safe distance and in real time, crucial differences in body temperature at an accuracy of up to 0.2°C – pinpointing any suspicious fevers in passing travelers.

raven-384 The Raven-384 is an infrared imaging camera, specially designed for the demanding security market. The thermal image is crisp and clear, even under difficult weather conditions and in complete darkness without the use of additional illumination. To meet the needs of the professional security community the Raven-384 can be configured with various lenses for short-range, medium-range and longrange observation. The camera interface can be PAL/NTSC video for a regular CCTV security network or optional Ethernet for a digital LAN. Standard delivery includes a common power supply and connecting cables. The integration and use of these infrared cameras are so easy, that no operator training is required.

With this IR camera solution for simple, reliable and stable operation in public places such as airports, bus, railway and metro stations, they are opening up an urgently sought and practical way to detect, at an early stage, dangerous viral diseases indicated by fever. As a diagnostic tool the Xenics Raven captures and displays on a PC screen linked via a simple Ethernet connection a high-definition infrared image at a high frame rate of 50Hz.

Temperature differences as small as 0.2°C can be detected, at a measuring sensitivity of 0.05°C. By using the reference method, putting a precisely controlled temperature reference in the field of view, Xenics eliminates the stability problem that microbolometer cameras usually have to cope with, thereby providing a stable and reliable screening. The high-definition image permits accurate fever detection in both individuals and crowds.

Generally, the measurement of body temperature from a distance is carried out with an infrared camera that detects the heat emitted from the human skin producing a temperature map like a camera in the visual realm recording a life scene. The result is a colour image whose various colour contours represent temperature gradients. Temperatures above a certain preset level can be highlighted.

Enabling reliable measurements, the unit requires only minimal set up and examination time. The Raven can be flexibly operated on a tripod or installed for permanent use. The company recommends the body temperature to be checked at the corner of an individual’s eye, where the temperature approaches the core body temperature. The examination takes no longer than a fraction of a second. Setup of the Raven is very simple. It requires minimum operator training of less than one hour before being fully operational.

Even a systematic, collected crowd screening is feasible via the Raven’s high-definition image. Automatic alerts can be triggered by adjustable thresholds preferably set at 1°C above average temperature, with visual and/or audible alarms. Operation of the Raven is discrete -at a 50Hz frame rate, there is no hampering of pedestrian flow. The Raven provides accurate and stable temperature measurement via precisely controlled black-body reference.

“We are broadening our product portfolio as well as our strategic presence in the world markets, changing from a mainly technology-driven to a fully market-driven approach,” says Xenics founder and CEO Bob Grietens. “In addition to our fast growing business in advanced InGaAs SWIR imagers we are entering the markets for uncooled bolometer solutions based on our application oriented R&D portfolio.”

See also our item on Swine Flu posted 5th May 2009.