Hinged lid up shows inside the vessel with the ‘sparge’
pipe for aerating/mixing the product
80GHz level
radar solution
for agricultural
bio-science sector
Contactless radar level sensors success in small turbulent feedstock vessel
he BASF Agricultural
Specialities Limited
production site in
Littlehampton, West
Sussex produces industry
leading biological pest control products
formulated from beneficial nematodes.
These products are used by farmers and
growers across the globe in agricultural,
protected ornamental and home and
garden markets. Liquid rhizobium
inoculants produced at Littlehampton are
also used as s eed treatments.
T
Nematodes are naturally occurring
microscopic worms, already present in the
soil, beneficial nematodes attack and kill
targeted garden pests. After application,
using a garden hose or watering can,
they attack the larval stages of pests and
slugs. Once inside, they quickly kill the
pest by releasing bacteria that stops it
from feeding. The nematodes reproduce
inside the dead pest and release a new
generation of nematodes, which disperse
to hunt down more pests. The research
scientists have isolated individual species
of beneficial nematodes that target only
specific garden pests including slugs,
vine weevils, chafer grubs, leatherjackets,
caterpillars, and codling moth. The state of
the art production facility in Littlehampton
produces trillions of nematodes in a form
that is easily applied by growers and
gardeners.
The production process involves several
stages of organism development and
growth in special vats, nutritional
feedstocks are added to provide perfect
98
PECM Issue 27
conditions to produce the nematode
product. As part of this, the feedstock
is mixed heated and aerated in a small
just over 1m high batching vessel before
adding into the process, ready for further
growth and development stages. The
container has ‘sparge’ pipes which blow air
up through the product to mix and aerate,
creating a turbulent foaming surface. The
lid is hinged and removable for cleaning
and inspection, so any long probe guided
wave radar would be impractical and
prone to damage, as well as causing a
cleaning issue. Of course, any pressure
based systems would have their level
reading affected by the changing density
during the process.
A few years ago, it was identified that a
contactless device, insensitive to these
conditions was needed. A 26GHz radar
was previously used, however, there were
some limitations on the performance
due to the small measuring range when
the liquid level was high and surface
conditions. Recently, BASF turned to the
new VEGAPULS 64 80GHz radar, which has
world leading sensitivity to handle both
the turbulence and foam on the surface
as well as condensation on the antenna of
the sensor.
It now provides a true level and contents
measurement over the whole vessel
height, the site Process Development
Manager commented, “The radar works
perfectly, even at very close proximity
to liquid when the vessel is full”. The unit
was supplied with the optional Bluetooth
communications, which allows set up via
Smartphone, Tablet or PC. It was just as
well, as during the set up, the Manager
also reported, “My computer got destroyed
by accident during the setting up of the
radars. So I loaded up the VEGA Bluetooth
App on an old iOS phone. I have to say
I was impressed.” 80 GHz contactless
radar is offering new solutions to level
measurements that were previously
thought impossible with a contactless
device.
As well as handling these challenging
conditions, they are also capable
of measuring very low reflectivity
hydrocarbons, long ranges, even
liquid gases, pure solvents, seeing past
complicated vessel internals, long nozzles,
even operating through process isolation
valves. The customer concluded, “There
is always excellent technical support by
VEGA, from legacy devices we have had for
many years, through to latest innovations
like this radar”.
www.vega.com/uk