New Process Gas Analyser for CEM @ProcessingTalk #PAuto

A new hybrid laser based process gas analyser now introduced by Emerson Automation Solutions has the potential to reduce the cost and complexity of CEM systems. It requires no consumables and needs minimal maintenance.

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In the midst of increasing compliance demands for emissions monitoring and nitrogen oxide (NOx) measurement in industrial applications, companies now have the opportunity to move beyond costly consumables and complex gas sample treatment associated with ageing, legacy measurement systems. The new Rosemount CT4400 Continuous Gas Analyser from Emerson is the world’s first purpose-built Quantum Cascade Laser (QCL) and Tunable Diode Laser (TDL) analyser designed to help plants reduce ownership costs and report emissions accurately in environmental monitoring applications. It gives simple measurements of all standard gases of interest, such as nitric oxide (NO), nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), and oxygen (O2).

Optimised for cold and dry applications running at ambient pressure, the Rosemount CT4400 analyser offers the benefits of QCL/TDL technology, including high sensitivity, accuracy, improved stability, and low-drift performance in a configuration that allows fast, easy integration into existing plant infrastructure.

“Our customers are looking for a better way to measure emissions without the on-going high costs or need for frequent calibration and complex sample preparation that requires NOx converters or ozone generators,” said Paul Miller, managing director for Rosemount Quantum Cascade laser analysers, a part of Emerson Automation Solutions. “The Rosemount CT4400 Continuous Gas Analyser gives them an answer to their exact requirements in a configuration they can just plug into their existing systems and be off and running – at a lower cost than previously possible. The reduced complexity of the system over what most companies are used to, results in higher reliability and analyser availability with a lot less personnel time required.”

Because the system can hold up to four laser modules, it can measure up to seven application-specific gas components simultaneously, providing great flexibility in continuous emissions monitoring systems (CEMS) applications. This simultaneous, multi-component analysis within a single analyser reduces the need for multiple analysers, and thus the cost.

At the heart of the Rosemount CT4400 is Emerson’s QCL technology, which detects and measures gas molecules in both the near- and mid-infrared wavelength range. The system employs a patented laser ‘chirp’ technique that enables the detection of individual gas species, free from the cross-interference effects of other gas components in the stream, making the measurement highly accurate and stable down to sub ppm concentrations. This high performance ensures operators meet increasingly demanding regulatory requirements, while real-time reporting provides critical insight into process performance.

Due to its purpose-built design, which produces enhanced performance at a lower cost, the Rosemount CT4400 Continuous Gas Analyser ensures reliable detection and monitoring of gases and allows operators to avoid costly regulatory fines or unexpected shutdowns.

More information on the Rosemount CT4400 Continuous Gas Analyser can be found at www.Emerson.com/RosemountCT4400.

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Electrocomponents plc buys Monition, adds to RS

Electrocomponents plc has today completed the acquisition of Monition, the UK-based pioneer in the design, development and application of condition monitoring systems. Monition is based in Worksop, Nottinghamshire, and will become an operating brand within the RS Technical Services operation.

Monition provides managed services in areas such as condition monitoring, predictive maintenance and the Industrial Internet of Things (IIoT) to improve their customers’ reliability, operability and maintainability. Originally founded in 1988 by Ian Jennings, Monition has more than 30 years of operational knowledge and expertise in the reliability and condition-monitoring sector, developed in co-operation with European and UK governments, leading Universities and industry specialists. It has well-established relationships within the maintenance functions in a range of blue chip clients, particularly within the food and beverage sector.

“The acquisition of Monition supports our strategy of building a range of differentiated value-added solutions such as connected factory and IIoT solutions for our customers,” said Pete Malpas, Managing Director of RS Northern Europe. “Whilst we already have an extensive range of customer solutions including calibration, eProcurement and inventory management solutions, we believe that the Monition portfolio will enable us to provide our customer base with the intelligent solutions they need to maintain their operations more effectively and as such will bring us closer to becoming first choice for our customers. We are thrilled to welcome Monition to RS and the Electrocomponents Group.”

Mike Burrows, Managing Director of Monition, commented: “We are extremely excited to become part of RS and the broader Electrocomponents Group. We share a common vision to deliver high-quality, innovative maintenance solutions to our customers. Being part of a larger Group will bring Monition benefits of scale and additional resources, which will help us accelerate the design and development of cutting-edge maintenance engineering solutions to address Industry 4.0 and digital manufacturing needs.”

Monition will retain its trading name and, as part of RS, will benefit from the financial strength, scale and international spread of the broader Electrocomponents Group.

Electrocomponents is listed on the London Stock Exchange and in the last financial year ended 31 March 2018 had revenues of £1.71Bn.

The European Scene

The German organisation Profibus & Profinet International (PI) publishes annual statistics on the numbers of devices installed with interfaces equipped with their communication technologies, which also include ProfiSafe and IO-Link. The trend towards Profinet increased in 2017, with 4.5 million new nodes installed, an increase of 25% on the previous year figure, which brings the total number installed to 21 million. Possibly because of the rise in Profinet systems, the Profibus DP numbers added seem to have reached a plateau over recent years, with a population of 60 million.

Profibus PA and ProfiSafe node numbers are growing strongly in the process automation field, with the ProfiSafe adoption growing 25% in the year, adding 2m nodes to reach 9 million in total. Similarly IO-Link device numbers installed in the year increased 50%, adding 2.8m to achieve a population of 8.1 million, linking sensors and actuators to a PLC as a subsidiary network below the fieldbus/Profinet level. PI recently published an IO-Link wireless specification, and demonstrated the technology at the Hanover Trade Show earlier this year.

Government Interferences

Legislative rulings have affected businesses and consumers across the EU recently, with the European Union’s General Data Protection Regulation (GDPR) causing avalanches of email asking for a subscriber’s permission to be re-registered with every firm they have ever dealt with, to allow them to record the fact. Even companies from outside the EU will face financial penalties, if they send out emailed newsletters or promotional messages into EU subscribers, without having these permissions confirmed, registered and recorded!

In the USA, the EPA, under the Trump administration, has dropped most of the more Draconian measures that they had originally proposed to impose on chemical plants, after the explosion at West Fertilizers in Texas that killed 15 fire-fighters and injured 260 people. The CSB report on the incident also listed 19 other Texas facilities that store large amounts of Ammonium Nitrate fertiliser, and are located within half a mile of a school, hospital or nursing home. One regulation that will be introduced in Texas is that local fire marshals will inspect all sites storing ammonium nitrate, once a year. Hopefully this might help prevent any further explosions that might result in large off- site consequences.

The changes that were proposed by the EPA and that will not now be introduced include (1) the need to evaluate options for safer technology and procedures that would mitigate hazards; (2) the requirement to conduct a root-cause analysis after a catastrophic chemical release or potential release incident; and (3) performing a third-party compliance audit after an accident at a plant involving the release or potential release of chemicals.

In the UK, Barclays Bank, rather than the Government, is reassuring UK exporters worried about Brexit and trading afterwards, with a survey that shows 39% of International customers would be more inclined to buy a product if it displayed the Union Jack. This was especially true for consumers in Asia and the Middle East (India, 67%; UAE, 62%; China, 61%), and also for younger consumers generally, where nearly half said this would encourage them to make a purchase. For over 55 year olds (who maybe had more life experience) the figure dropped to a quarter. It’s all statistics!)

Research projects

Splitting water into hydrogen and oxygen was first demonstrated by Fujishima and Honda using a titanium dioxide electrode. Since then, scientists have been on the hunt for the ideal material to perform the task, as Hydrogen is a very useful, green fuel for portable power. Now, a team from Exeter University has made a significant hydrogen energy breakthrough, developing an electrode that splits water using only light. The photo-electrode, which is made from nanoparticles of lanthanum, iron and oxygen, absorbs light before initialising electrochemical transformations to extract hydrogen from water. The team is currently working on further improving this material to
make it more efficient, to produce more hydrogen.

At the Drives & Controls Exhibition in the UK this year all the motor manufacturers were showing the condition monitoring capabilities of their offering, usually measured by vibration monitoring sensors. Possibly ABB went one step further, showing a sensor assembly that can be attached to almost any low-voltage motor, existing or on a new project. Transmitting information over Bluetooth, the sensors require no wiring, and are attached directly to the motor’s frame. Within the unit, sensors collect vital data points like vibration, sound and temperature, and upload that information via an ABB gateway or Smartphone to the cloud, where it is analysed. The results are sent back for optimising performance and predictive maintenance, just like a roving maintenance engineer!

This article was written for the July issue of the South African Journal of Instrumentation and Control, published by technews.co.za

Plant control systems and the internet

The following is my personal view of the business planning quandary faced by the major automation companies, first expressed in a Comment page published by Technews.co.za in the South African Journal of Instrumentation and Control, SAIC, March 2018 issue:

It is a common saying that the pace of technology change accelerates with time: although possibly as the observers get older, they become set in their ways, and cannot keep up.

This is certainly true, in my experience: I am getting older, set in my ways, and struggle to keep up. However:

It is not only the pace of such changes, but the speed at which the changes are spread across the ‘world market’, that makes new technologies so rapidly applied and, sometimes, profitable. In consumer markets, the effect is most evident, with the spread of mobile phones and mobile computing: possibly this would all not have come to pass without the availability of the Internet fuelling the spread of information. But for automation, and industrial sensors, has the technology change been rapid? I believe it has, and believe it is now accelerating ever faster, taking advantage of the advances made to meet the demands of other users. This has been evident, and mentioned in these columns, in referring to wireless sensors, batteries for self-powered devices, and self-power from solar or vibration or heat energy. There are many more developments that should be included in that list.

The problem for Automation companies

But how are the major sensor and automation companies driving this growth into their businesses using advances in technology: what are they researching? Where are they investing to get a business advantage? I think that their business planners are having a difficult time at the moment.

Around ten years ago, the big new technology coming to the fore was wireless communication from battery powered sensors. The large automation companies, like Emerson and Honeywell, invested heavily into this technology, and there was the inevitable confrontation between two rival systems – WirelessHart and ISA100. The automation marketplace thrives on such confrontations, for example the spat between Foundation Fieldbus and Profibus. It happens in other markets too; think of Blu-Ray and standard DVDs, PAL and NTSC TV systems etc.

Other perceived growth areas

After the wireless investments blossomed, the Internet was looming, and everyone believed they had to take advantage of the data that could be collected, and networked. Certainly Emerson and ABB went heavily into power network control systems, but ABB had major product availability and systems installation capability in the power industry and has made real progress. Emerson eventually sold out of this network power business, but retains the Ovation DCS used for thermal power station control on site.

Automation companies also bought into the long-established, relatively dormant and slow market of condition monitoring systems, by acquiring the companies quoted to be ‘active’ in the field, who had the ‘black art’ knowledge of industrial condition monitoring. Personal experience, back in the ‘70s, has taught me what a hard sell and difficult market even the simpler condition monitors offer, monitoring bearing wear etc, and that hardly suits the major project potential that might be of interest to big contractors. Complex systems, such as those applied to turbines in power stations, did offer potential, but needed real specialist back-up.

Additionally, the people in the business, such as Schaeffler perhaps (once again the product suppliers with the customer base), slowly developed their own bearing monitoring systems, ranging from portable hand-held units to bigger wired/wireless systems – these are the ones that I believe will succeed in this market. An alternative approach adopted was based on wireless technology developments, which needed a central monitoring system, the ultimate goal for the automation guys. Sensors for steam trap monitoring were designed by majors such as Emerson, to expand their plant control systems into condition monitoring for the plant engineers.

Sure enough, after a slower start, steam trap companies such as Anderson (US) and Spirax Sarco (UK) developed their own systems, and had the market entry with the customers using their traps. The opposite approach was adopted by Yokogawa, which is the pioneer of ISA100 industrial wireless systems. They created alliances with people like Bently Nevada, the bearing condition monitoring sensor people, and with Spirax Sarco on steam traps. Maybe this was to be able to reverse sell them the back-up products and technology for wireless systems, or maybe to hope for the potential of a plant monitoring control system supply.

Software systems

Most of the automation majors have alliances with the large software and computing companies, like Cisco and HP. The current approach seems to be to use these alliances to piggy-back a 24/7 plant monitoring system using the Internet, supplied as a service across the world. Again, I believe the companies with the product on the ground, the stuff that needs monitoring, will be the major players. Here it looks like GE, monitoring its own brands of refrigeration compressors, large pumps and gas turbines at power stations and offshore etc. are best placed.

The future

The quandary is where the Internet will help the industrial control systems and sensor suppliers expand their businesses in the future. The answer deduced above is stick to what you know and what you are known for. The irony is that the major with the best potential now is Rockwell Automation, with its systems based around Ethernet communications, interfacing with anything, plus their onsite Ethernet hardware, with control systems already configured to deal with such varied inputs. Maybe this was why Emerson made an abortive take-over offer for Rockwell late last year. The potential has also been seen by Profibus, who are pushing forwards with their Profinet, and where they go, Siemens will always be in the background.

ABB automation increases capacity 10x for Tate & Lyle food additive plant

When Tate & Lyle acquired Biovelop, a Swedish manufacturer of oat based food ingredients in 2013, the factory in Kimstad, Sweden was modernized and expanded by installing automation systems, variable speed drives, motors, motor control cabinets  and valve positioners from ABB Automation. In 2016 the remodeled plant celebrated the first anniversary of operations with the new systems and significantly increased production capacity.

The global market for specialty food ingredients, including health and wellness products, is growing, with annual sales of $51 billion and annual growth rate of 4-5%. Oat ingredients have been actively involved with this trend as they offer some key nutritional and functional benefits. In particular, oat contains beta glucan, a soluble fiber that has been shown to lower cholesterol and reduce post prandial glycaemic response – claims that have been approved by the European Food Safety Authority (EFSA). In fact, it was these properties of the grain that made the sector an attractive one to Tate & Lyle, and triggered the decision to diversify its portfolio into this sector.

“We have seen a more than tenfold increase in capacity with the same number of shift operators compared to four years ago,” said Annika Werneman, Tate & Lyle plant manager. “It’s a huge change in such a short time, and it means that we’ve gone from a low-level facility to one that can deliver high quality product to our customers globally.”

Advanced automation technologies in the plant run critical food processing equipment -including pumps and decanters: material handling machinery is also used to transport the dry food products. ABB delivered automation equipment that included 85 variable speed drives (VSDs), with power ratings ranging from 0.37 kW to 55 kW, as well as ABB MNS 3.0 motor control cabinets and low voltage motors. ABB also delivered 44 Digital Electro pneumatic positioners (TZID-C) , which use the Hart protocol to communicate with the control valves.

“We needed a process that was highly automated and could run 24 hours, seven days a week, all year long,” Werneman continued. This meant building a system that enabled Tate & Lyle engineers to digitally interact with the system, commission (start) devices, and diagnose performance deviations or failures from anywhere in the world. This not only helps ensure operational consistency, but also reduce the total cost of ownership by enabling staff to manage the processes without being physically present at each site.

Such interactivity was enabled by the ABB fieldbus automation for the drive controls, providing flexibility as well as remote monitoring of the plant performance. “I like that ABB designed the system so that the fieldbus responsible for device control is split from the fieldbus used for asset management,” explained Leo Dijkstra, power & controls team leader Europe at Tate & Lyle. “This ensures that I can make any changes to the configuration of the devices without the risk of the whole network going down.”

At Tate & Lyle, they place great importance not just on what they do, but how they do it. “We are working continuously wherever we can to reduce the environmental footprint of our operations,” said Dijkstra. ABB was well placed to help as it has developed a portfolio of products and solutions that improve industrial energy efficiency.

“In our pump applications alone, we are using up to 50 percent less energy thanks to the variable speed drives, and these have been running non-stop for the last two years without a single failure,” Dijkstra continued. “What’s more, ABB was so quick to deliver products that we even had the first VSD delivered in just a few days.”

Although the nearest ABB support is only a ten-minute drive away from the Kimstad factory, the fieldbus flexibilities in the drives enable Tate & Lyle to rely on its own staff to handle the ABB equipment remotely. “Our work with Tate & Lyle illustrates the benefits of digitization, which can yield immense productivity and output gains from existing facilities,” said Petter Hollertz, area sales manager at ABB. “The improvements at this plant also show what great teamwork between the equipment supplier and the user can accomplish, as we worked together as true partners on this project.”

The mystery of intelligent sensor diagnostics

The fashion, or trend, that has developed over the last few years for process and analytical instrumentation sensors is to use their on-board intelligence to monitor their own performance status. They achieve this by monitoring and tracking various diagnostic measurements – secondary parameters where consistent values are said to indicate the sensor is working as it should, and has not been subject to any changes since leaving the factory.

This approach is easily understood if you consider the possible effects of exposure of a sensor to excessive temperatures, which might soften the potting or glues holding a sensor to a ‘window’ – and it can be expected that this would be detectable. The addition of a diagnostic sensor, such as a temperature probe, within the sensor housing, could also be an option for checking the sensor condition, and alarming if the sensor exceeds a high or low set-point.

But how else do sensors check their own performance, and how relevant are these “checks”? This topic was discussed in the latest issue of the South African Journal of Instrumentation and Control, August 2017 issue: SAIC is a journal produced by technews.co.za.

Modern (intelligent?) sensors

So, over the past two years of attending and listening to presentations, and reading relevant articles describing the advantages of self-monitoring systems and sensor diagnostics, waiting for an engineer’s explanation as to how the clever monitoring system actually tells the factory instrument engineer anything, it is a bit of a disappointment to report that there seem to be no suppliers that actually make any significant disclosure. This applies across sensors ranging from ultrasonic and Coriolis flowmeters, electromagnetic flowmeters, level measurement systems using radar or ultrasonics, and level alarms. Obviously all the major suppliers are involved in such equipment, and compete with each other, but this secrecy seems a little extreme.

The problem is possibly that until a manufacturer can point to a failure that was detected – or anticipated – using their diagnostics, and decides to publish it, the user population has no idea what systems might actually work. But equally, by publishing a success for the diagnostics, the same manufacturer is saying that one of his sensors failed – and that is a very unusual event, these days. Plus also maybe not something they would wish to publicise.

The older approaches

The whole idea of diagnostics and sensor monitoring has been around for a long time. From personal experience with Bestobell Mobrey, in the 1980s, Mobrey launched an ultrasonic version of a float switch, the ‘Squitch’, which switched a two wire mains connection through a load circuit. When not alarmed it just sat there taking a small control current. For customer reassurance that it was operating in this quiescent state, there was a blinking red LED to show that the sensor was ‘armed’ and operating normally. Mobrey called that a heartbeat indicator, a term that is now used more widely.

For custody transfer flowmeters, the classic approach to validate confidence in the reading is to use two meters in series, and check that both give the same answer. This has progressed to having two separate ultrasonic flowmeters mounted in the same flowtube, on some installations.

For the more safety conscious plant there are often requirements for duplicated sensors for such duties as high level alarms, where two different technologies are used by the sensors – e.g. by mixing float, capacitance or ultrasonic level alarms.

The modern approach

It seems that the ultimate approach is to let the sensor supplier link into your plant automation and data system to interrogate the sensor, and he will verify the measurement and performance diagnostics on a regular basis. With many and varied sensors, this leads to a lot of external interrogation of your plant assets, and possible worries over losing control of your plant.

Overall, it begins to look as though it is becoming impossible for a discerning plant engineer to decide which supplier has the best performing diagnostic system to monitor the relevant sensor’s performance. Rather like opening the bonnet of a modern car, and deciding it would be best to take it to a garage!

At a recent lecture on this subject, held by the InstMC Wessex section in co-operation with Southampton University, a detailed discussion concluded that the sensor suppliers now have all the real expertise in-house and a normal plant engineer could not be expected to cover the depth of this technology for all the many sensors and other equipment within his control. In the end the decision as to ‘which supplier to use’ returns to your own previous experience, including the service and support that has been and is now on offer, and the suitability of the product for the money available for that sensor task.

False alarms from safety sensors?

So I do know about sensors and control systems, from the supplier point of view. But maybe like many suppliers I’ve only been on site to troubleshoot a sensor that is reported to be giving incorrect data. So someone else made the decision to question the validity of the sensor outputs.

These days, the nearest I get to regular sensor monitoring is at home, typically with smoke alarms, a CO monitor, and a flammable gas alarm. Plus the plant manager, my wife, is always demanding an immediate solution to any alarm system going off, to continue production.

The problem

A flammable gas alarm was positioned above the gas hob: perhaps in retrospect not the best place, as the instructions said humidity and steam should be avoided. But very quickly we realised that the detector was not very tolerant of any wine added to dishes being cooked on the hob. Then, surprisingly, it alarmed whenever we had bread dough baking in the (electric) oven. Since the detector was said to be set to alarm at 25% of the LEL this was surprising.

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The instruction came down – ‘Get me a switch in that alarm circuit, so I can switch the piercing noise of the alarm off!’ So, there was my solution, and a task, so that was done. I did not think it through any further.

Time passes

This system worked well for maybe 3 years. The alarm switch changed power from the alarm to a lamp over the worktop, so we knew to switch it back on after a problem event. But such sensors must have a life, and so when the alarm started going off when the kettle boiled and steam drifted up past the detector, I thought the unit was failing. There were then several late evening alarms, for no apparent reason, and we could not smell any gas (it is difficult to detect these days), nor see anything untoward. Like every engineer I guess, I felt the sensor, to find it very hot. This seemed to confirm the problem, that the sensor was failing, so take the thing out – ‘it was not that hot before!’ Something had changed.

Six months later, this Summer, we had a new gas meter – a Smart unit – installed on the domestic gas supply. Ultrasonic measurement of the flow, wifi connection to the indoor display, and mobile network reporting usage figures to the supplier. That would all be great, except the fitter refused to reconnect the gas to the house, because of a slight leak detected indoors. We had to call out a plumber to deal with our in-house problems. Good job it was Summer, as that took over a week.

Finding the gas leak

The leak was located as somewhere in the piping to the gas hob. The plumber tightened up the connections under the hob, and repeated the pressure loss checks. Still a slight leak, but within allowable tolerances. OK, so he checks once more, to be sure, and starts his paperwork. A last twist of the 90 degree bend directly on the hob (supplied by the Chinese supplier) produced an interesting result: the threaded part of this connector sheared off, almost in two half-round pieces. It looks like steel, but low grade steel, and showed a brittle type fracture all around the fitting.

Presumably the crack that had been there before, allowing a slow leak, had led to the fracture on tightening the connection. That was installed 10 years before, and no-one had done any checks of that or the system post installation. OK, I had never had the systems tested for gas leaks.

What had happened?

The conclusion at this point was that the slow leak presumably collected gas in the lower cupboards, and when this escaped it combined with the wine vapours to trip the alarm. Possibly the steam from the kettle just accelerated the rise of the gas past the detector. The detector was presumably a Pellistor, and got hot because it was burning the gas off. The dough rising in the oven? I don’t know much about bread and dough – but the leak was directly above the oven, so maybe the gas and air, warmed from the sides of the oven, helped the gas rise up past the detector. If that fitting had actually failed totally one night, there would have been a major blast, as I had removed the gas detector.

We now have installed a new detector, further from the cooking (3 metres). Plus the old one is re-installed, as a back-up unit: it is working OK still, next to the boiler. The bad news: the new alarm went off last weekend, when simmering a Paella laced with white wine….

Yesterday the plant manager produced a batch of dough and made bread. Both flammable gas alarms went off, first the unit 3 metres away then the old reserve unit, now even further away in the utility room, with the boiler.

Legislation

In any rented accommodation the landlord has to have a gas system safety check once a year. Because we own our own house there is no such requirement, and the boiler service man, who checks the gas boiler and heating system once a year, is not required to, and does not include, a system gas leak test in his inspection.

Product or system failure?

The gas hob was made by Proline, and installed around 8 years ago by a registered installer. It was a Chinese manufactured unit supplied by Comet as a low-cost own-brand hob to many retail outlets in the UK. The 90 degree bend that failed was supplied as a part of the hob, the gas inlet port. It is not steel, it could be an aluminium or zinc alloy. It appears the design was such that this port could be stressed during installation or tightening, as the bend itself would not rotate to suit the angle of the delivery pipework. It seems the break was on the hob side of the fitting. A combination of a poor quality fitting and a poor design.

The flammable gas alarm seems to work OK in detecting natural gas, but is even more sensitive to alcohol vapours, bread and dough making, and using any window cleaning spray that has any hydrocarbons in the fluid. So beware of using them in a brewery, distillery, bakery, bread shop, pub, restaurant and so on!

There was undoubtedly a small gas leak, around the hob, which has now stopped. Possibly this was from the 90 degree bend fitting, which then completely broke apart on tightening the joint. It remains possible that this failure was an accident waiting to happen.

The domestic plant manager is none too pleased at the moment. So do I leave the sensors installed, take both or one of them away, or fit switches to suppress the noise and turn off the alarm(s)?

Postscript

The supplier of the unit is surprised and upset. He considers these sensors do not give false alarms, when exposed to wine fumes from simmering a paella, or from baking bread in the oven. He has asked me to return the newest one to allow him to test it.

This has been done so we will see what results!