Specifications

Document No. DER04098 OPERATING INSTRUCTIONS
Page 16 of 19 Effective Date 06 Jun 08
4. Set all six weir plates to the same diameter.
5. Re-install access plate on case cover.
Figure 4098-16 Weir Plate Adjustment
Differential Speed/Conveyor Torque
Generally, a faster conveyor speed results in lower conveyor torque, as solids are discharged
faster and usually wetter. Reducing conveyor speed must be done slowly and cautiously, allowing
steady-state to be reached before further reduction. Slower conveyor speeds permit solids to
remain in the bowl longer. This can permit solids to accumulate in the bowl if the input rate
exceeds the discharge rate. Therefore, the torque must be monitored to prevent overload.
Torque limit settings control automatic feed reduction and centrifuge shutdown. As conveyor
torque rises, the feed rate is gradually reduced. If torque continues to rise, the feed rate is more
rapidly reduced. Upon reaching the maximum conveyor torque setting, the centrifuge is shut
down.
At certain conveyor speeds the drive motor must reverse direction to accommodate the differential
speed relationship with the bowl. If this occurs, the centrifuge control system automatically
assumes control of the feed pump to reduce its flow rate. The message “Automatic Flowrate”
appears on the Operation screen to alert personnel that the feed pump is under automatic control.
When the reduced feed rate is reached, an 8-second timer is started. Upon expiration of the timed
interval, a new conveyor differential speed is applied to correspond with the revised flow rate.
The feed pump remains under automatic control until the operator intervenes by re-setting the
Pump Input GPM. Manual control of the feed pump is then restored. This action releases the feed
pump from automatic control and clears the Automatic Flowrate message from the screen.