For transport of the coffee, Probat prefers the pneumatic conveyance. As the
conveying air is in direct contact with the product, it has to be absolutely oilfree. For production of the conveying air as negative pressure, Probat has used Aerzen units since 1996.
In September 2012, Probat opened a new Research and Technology Centre. There, the conveying air required in the roasting machines is generated by two Delta Blowers Generation 5 and one Delta Hybrid. Upon storage of the green coffee into silos with overpressure between 1,000 and 2,000 mbar, the Delta Blower is used, also during transport to the roasting machine with positive pressure.
The Delta Hybrid is responsible for transport of the particularly sensitively
roasted beans to the roasted coffeesilos and to bagging station with negative pressure as well as for transport to grinding plant with overpressure. The Delta Hybrid unit generates a negative pressure of 300 mbar on suction side as well as an overpressure of 600 mbar on discharge side. Therefore, a conventional blower unit could be replaced acc. to the principle “Two become
Again, two Delta Blowers transport the ground coffee to the ground coffee silos and to the packaging machines with negative pressure. As an alternative, however, the Delta Hybrids can also be used. The required differential pressure is decisive for the selection dependent on the piping length and the specific energy advantages of the Hybrid.
All Aerzen units are fully automatically integrated in the process of the roasting equipment and are switched via a superordinated intelligent SPS control depending on the program. The respective blower units are driven with a constant volume flow whereby the pressure is built up depending on conveying capacity and pipe length. Thanks to a bypass solution, Aerzen
had developed together with Probat, a part of the volume flow can be led back from discharge to suction side for the positive pressure units.