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Capacitive sensors are suitable for detection of granules or powders and can
look through sight glasses, non metallic windows or container walls to detect
powders or granular material on the other side. This avoids the requirement for
piercing containers and allows maintenance without creating a leak point in the
container.
Sensatech create custom capacitive sensors for a number of powder or
granular level detection applications where an OEM requirement exists.
Examples:
In Plastic Moulding:
Raw materials for plastic moulding is often in
granular form. To ensure material integrity granules are often processed
through feeding systems including dehumidifying dryers and colour mixers.
Conveyance is via vacuum conveyors to moulding machines where components are
formed. The feeding process, especially where drying is included can involve a
time delay, granules perhaps taking 20 minutes to pass through the dryer so it
is vital for continual operation that levels are maintained in feeding hoppers.
The use of capacitive sensors allows automated feeding of hoppers from bulk
bins.
In Printing and Copying:
Modern photocopy machines use a fine powdered
toner electrostatically transferred via a drum onto paper before being set by a
heating process. As with the other examples it is important to maintain a feed
of toner and warn users to replenish toner when it falls below a
level.
Capacitive sensors are one of the most cost effective sensing
techniques for this application where characteristics of the toner material can
for example compromise optical techniques.
In Baking:
With increasing automation in baking, flour is required to be
conveyed and fed into the baking process in a similar way to the example of
plastic moulding. Capacitive sensing again provides a suitable and perhaps the
most cost effective solution for this application. |
