The new generation of measuring instruments follows the principle of radically simplifying level measurement with radar devices. The development to this state of the art in measurement technology was already set in motion 20 years ago and now suppliers are finally doing away with the decision between bulk solids and liquids.
Since 2016, the manufacturer Vega from Schitach has consistently relied on 80 GHz technology in its developments, which is characterised by particularly precise signal focusing, great dynamics and a high level of protection against interference. In addition, a particularly narrow signal echo makes it possible to maintain very small distances between the sensor and the surface to be measured.
With the new generation of measuring devices (here the ‘Vegapuls 6x’), this property has been refined to such an extent that a distinction between liquids and bulk solids is no longer relevant. Thus, it is possible to reduce the distance between the sensor and the surface in the silos from 80 cm to 30 cm and thus (economic advantage!) to better utilise the silo volume.
Redefining the SIL Level
Plant and machinery can pose risks that are so threatening that people and the environment must not be exposed to them under any circumstances. If such a hazard exists, the existing risks must be reduced to meet the safety requirement. One measure of this is the ‘Safety Integrity Level’ (SIL), which makes the risk reduction quantifiable. Ultimately, however, SIL is also quite clearly a device property.
Vega’s application has also taken care of this aspect. Such 80-GHZ applications must be developed differently from the ground up if the requirements for functional safety according to higher SIL are to have an effect. The new radar chip achieves failure rates that exceed previous standards by a factor of ten. This is achieved primarily through innovative self-tests in which the test signal is fed into the very front of the antenna and thus the complete measurement chain from said antenna to the sensor is taken into account. This reduces the failure rate to almost zero, as the manufacturer points out.
Advantages for the Chemical Industry
And something else could be realised: For the chemical industry, the pressure and temperature range of the devices could be noticeably extended. This is achieved by the fact that the antennas, which were previously filled with plastics, can now also be filled with ceramics, making applications with temperatures from -196°C to +450°C and pressures between -1bar and +160bar possible.
The trend is clear: the users simply decide on the basis of their application how the device is configured. And in any case as uncomplicated as possible.