Endress+Hauser has announced the names of the three recipients of this year's Patent Rights Incentive Awards. The awards, worth Euro10 000 each, acknowledge the three patents that demonstrate the most economic importance of those issued in 2005. This year they were presented for inventions in level measurement, flow measurement and digital data transmission.
Developers in the capacitive pressure measurement field are always looking for ways to make improvements. However, this is a difficult task in a field where almost everything has already been tried and tested. The principle of this technology takes advantage of the fact that the pressure of the gas or liquid to be measured alters the capacity of a capacitor, that is, its ability to absorb an electric charge. Dr Robert Lalla, an electrical engineer, has improved upon this by developing a new circuit configuration. "It is capable of analysing the signals transmitted by pressure sensors from completely different 'sensor worlds', and can easily be programmed to adapt to different types of sensors," says Lalla. Even if the pressure exceeds the measuring range, the construction will not be affected because it will identify the event and generate an appropriate signal. The circuit is manufactured as a small silicon chip according to established standards, thus reducing the risk of error and quality defects as well as increasing reliability. The new circuit also renders more precise measurements.
Coriolis flowmeters work on the principle of 'vibrating pipe' technology whereby the mass of liquids or gases flowing through the pipes influences the vibration of the pipe. However, high internal pressure causes a minor systematic error because the pipe warps very slightly under pressure which is enough to affect the sensitivity of the measuring device. The larger the calibre of the pipe, the greater the discrepancy becomes. An invention by Dr Martin Anklin-Imhof and the late Dr Alfred Wenger minimises this effect. These two physicists used rings to stiffen the pipe in certain places. "The rings are relatively small thus their mass is negligible and the sensitivity of the measuring device is practically unchanged," says Anklin-Imhof. "At the same time, aberrations are three to four times smaller than without the stiffening rings - only about 0,1% per 10 bars (1 MPa) of pressure." This system is now deployed in Promass F type Endress+Hauser flowmeters with nominal values from 100 mm upwards.
Today's modern temperature probes digitally process measuring signals internally. To do so, the electrical circuits must be separated from the signal entry and exit. One possible way of achieving this is to use optocouplers - components that transform electrical signals into light signals, which are in turn received by photosensitive elements. The disadvantage of this system is that it uses a great deal of electricity which is scarce in temperature measuring transducers. Stephan Konrad of Endress+Hauser, Wetzer in Nesselwang, Germany, developed a circuit component that achieves this so-called galvanic separation by means of a small transformer. This solution requires hardly any electricity and is inexpensive to manufacture. "In calculative terms, the energy requirement is negligible - while the optocoupler needs between almost 20 and 30%," says Konrad. To date, this invention has proved its worth in many thousands of Endress+Hauser temperature probes.
For more information contact Tony Jacobsen, Endress+Hauser, +27 (0) 11 262 8000, [email protected]
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