1       DECANTER CENTRIFUGE GENERAL CHARACTERISTICS
The ANDRITZ decanter centrifuge is composed of a rotating assembly, driven by electrical motors, supported by two pillow blocks on a base frame. The rotating assembly includes a cylindrical and conical bowl, a scroll conveyor and a gear box, which creates the differential speed between the scroll conveyor and the bowl.

2    OPERATING PRINCIPLE

The ANDRITZ decanter is designed for a continuous attention-free operation, through a specific electronic system. The shutdown of the decanter can be programmed outside of the operators’ working hours on site and operating 24 hrs. a day is, of course, possible.

3    HIGH PERFORMANCE SCROLL

The ANDRITZ High Performance scroll has been designed to increase solids residence time in the process area (to reach lower moisture content) while optimizing the clarified liquid flow, reducing hydraulic  turbulences  which hinder fines and suspended solids capture.

Thanks to the open flight design, the clarified liquid travels axially towards the discharge area over the whole scroll section, instead of being led  by a  full  flight  around the  scroll hub  and  in  a  direction opposite to the scroll displacement.

The  low  velocities  and  the  laminar  characteristics  of  the  flow, drastically reduce the turbulences inside the bowl thus enhancing fine solids capture rate.

4       WEAR AND ABRASION PROTECTION

All  the  rotating assembly parts  facing possible abrasion are  protected by  the  most  resistant coatings

(tungsten carbide).

Field replaceable tungsten carbide tiles the entire length of scroll

5       ENERGY RECOVERY SYSTEM

Featured on our High Performance decanter centrifuges, the rotating assembly is driven by a main and a secondary motor. Each motor is controlled by a variable frequency inverter (VFD).

In  our  protected  design,  the  energy  the scroll needs to convey solids is recycled by the inverters. This energy is then fed into the main motor.

Operator-Friendly Controls

This unique system reduces power consumption up to 25% compared to standard systems.

Scroll speed and bowl speed are independent from each other. Consequently it is possible to adjust separately the G-Force (acceleration) and the solids residence time based on a change of the feed slurry characteristics.

The ANDRITZ centrifuge is designed for continuous, attention-free operation. The advanced centrifuge control system allows full monitoring and adjustments of the system. The start-up and shutdown of the centrifuge can be programmed to occur outside of the operators’ working hours and can also allow for 24/7 operation if required.

ANDRITZ supplies a complete control system with touch-screen interface which is capable of controlling the complete dewatering system including centrifuge, polymer system, sludge feed pump, wash-water flow and discharge conveyor.  The control system allows for totally automatic operation with operational features including Early Start, Extended Run, Pause & Resume and One Touch.   All ANDRITZ centrifuge panels include a modem to assist the customer with remote monitoring, troubleshooting, and software upgrades.

The centrifuge control systems are designed, programmed and assembled in-house in Arlington, Texas, and are not outsourced to third party vendors.

6    CYCLO-SUMITOMO GEAR BOX

This reducer creates the differential speed between the bowl and the scroll conveyor and bears the torque required to convey the solids out.

CYCLO®-Sumitomo™ reducers are compact and the internal parts do not include planetary satellites. This gearless proprietary design minimize frictions and provides for best efficiencies and torque capacities (able to support up to 500% of its nominal capacity).

The pond depth adjustment inside the bowl is carried out easily without dismantling the machine.

7    INSTALLATION OF THE DECANTER

The IN-LINE design of our ANDRITZ decanter centrifuges reduces the floor-space requirements to a minimum. Its isostatic design decreases vibrations and noise level.

The decanter resting on vibrations shock isolators (included in our scope) is typically installed on concrete supports.

The feed must be regular and homogenous by an adjustable flow rate positive displacement volumetric pump. An industrial water entry for decanter washing must be available (very low washwater consumption and only during the equipment shutdown).

The open solids discharge casing facilitates the installation of any evacuation system. We recommend the installation of an inclined shaftless screw conveyor with a bottom drain hole for the gravity discharge of the slops at the beginning and the end of each operating cycle.

The de-aerator captures and separates the air dragged with the centrate discharge and allow for its easy evacuation to the outside or any air treatment facility. We recommend the installation of sampling ports for the dewatered solids and centrate.

The power and control panel, in which the frequency inverters (VFD) will be mounted, should be installed in an electrical room with fresh air ventilation, without any contact with the dewatering room, in order to prevent electrical wires and electronic cards corrosion. A local control panel can be installed on a wall near by the decanter if required.

Dismantling and maintenance of the equipment is easy, through the use of a simple monorail. Scrolls can be removed in less than 10 minutes.