More than 60 industrial and scientific experts came from all over Europe, Asia and America, to exchange experiences and discuss the newest developments and future visions.
The programme comprised lectures by recognised international experts from both industry and science. The scope of application of SAW sensors is manifold, spanning from Formula One racing to space research.

The symposium was organised by the Villach-based leading research centre CTR Carinthian Tech Research. The feedback of the participants was very positive. So, there should be no obstacles to a continuation.

From left to right: Omar Elmazria – LPMIA – France, Viktor Plessky – GVR Rade SA – Switzerland, Sylvain Ballandras – FEMTO-ST – France, Victor Kalinin – TRANSENSE – England, Chairman Alfred Binder – CTR AG - Austria, Marc Loschonsky – SENSEOR – Germany, René Fachberger – CTR AG - Austria.

From left to right: Omar Elmazria – LPMIA – France, Viktor Plessky – GVR Rade SA – Switzerland, Sylvain Ballandras – FEMTO-ST – France, Victor Kalinin – TRANSENSE – England, Chairman Alfred Binder – CTR AG – Austria, Marc Loschonsky – SENSEOR – Germany, René Fachberger – CTR AG – Austria.

„Surface Acoustic Wave Sensoren haben nun den technologischen Reifegrad erreicht, um Applikationen in der Industrie umzusetzen“, betont Alfred Binder von der CTR und Conference Chairman. „Mit der Veranstaltung wollen wir darauf aufmerksam machen, dass sich viele ungelöste Aufgabenstellungen in der industriellen Prozesskontrolle – wie Einsatztemperaturen über 300 Grad Celsius, Erschütterungen, Strahlungen, Druck etc. - mit drahtloser SAW-Sensorik inzwischen lösen lassen. Wir schaffen damit erstmals in Österreich eine SAW Austauschplattform zwischen Industrie und Wissenschaft, die zum Diskurs anregt.“

Die Veranstaltung richtet sich an Interessierte aller Branchen, in denen Lösungen in Hochtemperaturanwendungen gefragt sind. „Das Interesse der Industrie an SAW-Sensorik ist sehr groß, da in vielen Produktionsprozessen einige hundert Grad Temperaturtauglichkeit gefragt sind.“ Anwendung findet die Technologie beispielsweise in der Stahlindustrie, wo Komponenten durch SAW-Tags eindeutig identifiziert und auch die Einsatztemperaturen ausgewertet werden können. „Auch in anderen Branchen können Bedingungen herrschen, die den Einsatz von SAW-Sensoren erfordern“, so Binder weiter. „Sei es in der Lebensmittelindustrie, der Erdölindustrie oder in der Luftfahrt, wo die Technologie beispielsweise den Verkabelungsaufwand bei Flugzeugturbinen reduzieren kann.“

Erstmals präsentieren SAW-Sensor-Hersteller und SAW-Sensor-Forscher ihre Anwendungen und neuesten Ergebnisse in einem speziell dafür geschaffenen Rahmen. Das Programm umfasst Vorträge von internationalen Experten aus Industrie und Wissenschaft wie Sylvain Ballandras (FEMTO-ST/ Frankreich), Omar Elmazria (LPMIA/Frankreich), Victor Kalinin (TRANSENSE/England), Marc Loschonsky (SENSEOR/Frankreich), Victor Plessky (GVR Trade SA/Schweiz) und deckt Anwendungsgebiete in der Stahl-, der Automotive-Industrie oder der Medizintechnik ab.

Binder: „Interessierte aus aller Welt wie beispielsweise aus den USA, Russland, Osteuropa oder Asien haben sich bereits angemeldet.“

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A COMET K1 project focused on developing an innovative solution to this high-speed problem. It was again radio sensors based on surface acoustic wave (SAW) technology that proved ideal for such highly demanding applications.

In this case the motor was subject to various different load scenarios during operation but overloading had to be prevented. As a result, predicted thermal loads on the rotor, e.g. from air friction, electrical load or stray loss had to be verified with measurements. When searching for a suitable sensor principle, the researchers were faced with the problem that standard wired sensor models could not be used because of the high speed. They therefore opted for SAW sensors, which are completely passive and can also transmit information wirelessly under extreme conditions, such as high temperatures or vibrations.

Snap shot
What was particularly challenging was the huge demands placed on the reader’s speed: at a rotation speed of 15,000 rpm the sensor is only within the scan antenna’s range for a very short space of time. This means that there are only a few 100 microseconds for detecting the sensor. SAW readers previously available however could only interrogate in the millisecond range. Increasing the speed by a factor of ten was achieved by developing a new scanner.

This project is also a great success for the researchers at CTR, as the development – particularly the fast scanner – is an important enabler for a range of exciting new developments in the COMET programme.

It all started with one great aim, which was to monitor the state of casting slide gates automatically at all times. What sounds simple was

however to turn into quite a hot project.

Like valves, slide gates are wear parts in the refractory industry used for controlling the flow of molten steel in continuous casting plants. They have to withstand temperatures of up to 1,540°C, mechanical loads from several tons of hot steel and chemical attack, e.g. from alloy elements. As a result, the slide gates have to be replaced as soon as a critical degree of wear has been reached, depending on the steel grade, casting parameters and casting time.

Under control by radio

But how can the state of the slide gates be clearly detected under such extreme conditions and the metal flow controlled? The answer was the surface acoustic wave (SAW) sensors developed by CTR that are completely passive and provide information under the toughest conditions (e.g. heat, dust, vibrations, radiation). Integrated in the slide gate, the wireless sensor will not only automatically detect the unique identification number but also temperature and other physical data in the future, thus enabling complete documentation.

Measuring during operation allows important conclusions to be drawn regarding the casting process and condition of the slide gate, ensuring that the components are replaced regularly. Definitely a hot innovation, as there are no comparable solutions on the market to date.

During the development work, the system was successfully tested several times in production at the steel works. Together with the partner company, CTR has applied for two international patents.

Source picture 1: RHI AG
Source picture 2: CTR AG

Mechanische Stöße, Hitze, Vibration, Strahlung, Staub oder chemische Substanzen – Viele verfügbare RFID-Tags sind für industrielle Anwendungen unter rauesten Bedingungen oft nicht geeignet. Vor allem in der Stahl- oder metallverarbeitenden Industrie sind hochtemperaturtaugliche Sensoren erforderlich Die hohe Temperaturbeständigkeit lässt sich durch SAW-basierende RFID- und Sensorsysteme erzielen. Neueste Erkenntnisse, wie diese selbst unter extremsten Bedingungen wertvolle Information für den Materialfluss von Stahlpfannen, Walzen oder Tiegeln liefern, versprechen mehrere aktuelle Projekte des österreichischen Kompetenzzentrum Carinthian Tech Research CTR.

Read more on www.rfid-im-blick.de

Transense Technologies is a technology transfer company based in Upper Heyford, Oxfordshire, UK. Transense develop Surface Acoustic Wave (SAW), wireless, batteryless, sensor systems in partnership with its licensees, Honeywell, Melexis, Michelin, Tai-Saw, Sengenuity and Stack.
Current SAW-based applications include Tyre Pressure Monitoring Systems (TPMS) and torque measurement systems for Electrical Power Assisted Steering (EPAS), IC engine control and driveline management.

One of the recent projects was to develop a torque sensor for KERS capable of operation in extremely harsh environment of F1 vehicles. The sensor was capable of measuring torque generated either by the KERS electric motor or by the car engine at a very high speed of rotation up to 18000 rpm. In addition it survived very intense engine vibrations, circa 100g, while the temperatures ranged from 70 to 170°C. The SAW torque sensor was used by one of F1 teams during 2009 racing season.

More information is available at http://www.transense.co.uk/technologies/kers .

Surface Acoustic Wave wireless sensors for high operating temperature environments

Surface Acoustic Wave (SAW) technology has been applied for more than 20 years to develop sensorsexhibiting unique capabilities with limited ageing effects resulting in long term stability properties.

During the 90s, they have proved their capability to be wirelessly operated without any on-board power supply.

In parallel, the long term development of advanced material, particularly in Russia, has yielded a new class of material, namely Langasite and its variant forms, that can be substituted to quartz and lithium niobate particularly when operating at high temperature.

More information on www.sawhot-project.com.

SAW (Surface Acoustic Wave)-based systems that are based on radio technology measure the physical dimensions of power lines such as temperature, pressure or voltage. These systems transfer high frequency signals via wireless technology, operate completely passive – without energy supply – and are able to withstand extreme temperatures (ranging from -55 degrees to +400 degrees Celsius). These properties qualify the systems for monitoring conductor strands.

The Austrian CTR AG is specialised in the development of SAW systems. CTR is currently working on the development of sensor technology to monitor temperatures in conductor strands. The Dresdner Lemke Diagnostics GmbH, a technology leader in the manufacture of diagnostic and monitoring devices for the power supply industry is especially interested in CTR’s technology. The permissible load on power lines depends on the temperature of the conductor strands. “So far, the temperature was estimated based on wind speed and environmental temperature, however, more detailed information requires precise measurements. Cable-based measurements do not work due to high voltage. Infrared measurements are impractical because of the intense vibrations of the strands. The SAW technology is the solution to all these problems,” Alfred Binder, SAW Program Director for CTR, states.

A reader on the power pole contacts the sensor mounted on the line via radio technology; the sensor transmits the temperature information that will be used to control the network load. Basically, the SAW-system is an automated system for load monitoring in high voltage power lines. The use of the additional information provided by the SAW technology allows transmission of different amounts of energy, based on existing environmental conditions, over the monitored lines. The first installations are currently under way.
The SAW sensor is composed of a piezoelectric crystal with metallic structures. The reader sends an electromagnetic signal that a special transducer (mounted on the SAW sensor) converts into mechanical oscillations. The waves thus created spread out on the crystal’s surface and are partially reflected by the reflectors and re-transformed into electromagnetic waves. Based on the reflectors’ distribution, a fixed code is detected which uniquely identifies the sensor. The crystal’s temperature-based contraction or expansion causes a runtime modification of the signal received. In addition to RFID, a temperature measurement with a resolution of up to 0.01 degrees C is also feasible. This additional property is especially useful in the case of challenging industrial uses.

Source picture: Doble Lemke GmbH

View article in RFID Journal (pdf – german)

Stahlpfannen, Karosserien in Lackierstraßen, Isolierung in Industrieöfen – ein Piezokristall als RFID-Tag liefert auch unter Extrembedingungen wertvolle Informationen, wie Temperatur und Identifikation. (RFID im Blick)

Die RFID-Technologie hat sich in der Logistik und Prozesskontrolle längst etabliert. Doch was, wenn Objekte – bei extremer Hitze, Staub, Erschütterungen oder hohen Strahlenbelastungen – überwacht werden sollen? Siliziumbasierte RFID-Sensoren erreichen hier bald ihre Grenzen.

Von Alfred Binder, F & E Manager, und Birgit Rader, Public Relations, CTR Carinthian Tech Research AG

Read more on www.rfid-im-blick.de