Screening technology with ultrasonic sensor

When the water level determines the performance –
Intelligent sieve technology with ultrasonic sensor

In 2002, we were faced with a particular challenge in our pulp and paper production: as many paper and pulp fibers as possible were to be recovered from the waste water before further processing. At the same time, the available installation space for a correspondingly large screening machine was very limited – with a very high solids load at times.

Together with nrw Anlagentechnik, we opted for an innovative solution, both then and now.

The screen used operates with a speed-controlled geared motor. At the heart of the system is an integrated ultrasonic sensor that continuously detects the current water level in the screen and thus automatically controls the speed of the brush cross.

When the fiber load is low, the brush cross rotates slowly or stands still. As a result, the openings of the perforated screen plate become clogged with fibers – a natural filter aid layer is formed. This enables a significantly finer separation than the actual screen width.

If the water level rises due to higher solids quantities, the system automatically increases the speed of the brush cross up to the nominal speed. This ensures the required throughput even at high loads, while a particularly high degree of separation is achieved at low loads.

The result: a reliable, energy-efficient solution with minimal maintenance requirements. In addition to this system, we also operate two other systems from nrw Anlagentechnik at this location – which have also been in reliable and economical use for many years.

Philipp Holzberger, Manager Pulp
Sappi Group