Sieving of fine
fraction: The spring-loaded gate for the fine fraction
is actuated by the cam profile based on the inlet position, which allows the
fines to exit the outlet port and fall through the arm into the storage
container. The cam profile is optimised to open the gate slowly at the
beginning (to minimize material loss) and faster once the connection of inlet
and arm is almost made. The vibration motor is running to facilitate size
separation. This operation continues until no more fines are registered
entering the storage container, which stops the motor. Optionally, the arm can
be moved back and forth to facilitate the separation process and prevent
consolidation of the soil in the sieve (see Section 4). The coarse particles
remain inside the inlet and the mechanism moves into position 4, where the
inlet is rotated ~ 110° back.