Applications Alfa Laval STNX decanter centrifuges are used for a wide range of different starch processing operations. These include dewatering heat-coagulated potato protein and maize gluten, 2-phase and 3-phase wheat starch and protein splitting, and fruit juice separation and fibre dewatering in the potato and tapioca starch industries. The STNX range provides the starch industry with the most cost-effective, high-performance solution, with the lowest power consumption and life cycle costs available. Design Alfa Laval designed the STNX range of decanter centrifuges with a focus on performance, easy access, reliability and low noise levels. The rotating assembly is supported on a compact welded box beam frame with main bearings at both ends. The in-line motor is flanged or foot-mounted on the decanter with adjustable brackets for belt tension adjustment. The bowl is driven at the conical end by an electric motor using a V-belt transmission. The bowl, conveyor, casing, inlet tube, outlets and other parts that come in contact with the process media are made of AISI 316 and duplex stainless steel. High-performance decanter centrifuge for starch production STNX decanter centrifuge Operating principles Separation takes place in a horizontal cylindrical bowl equipped with a screw conveyor. The product is fed into the bowl through a stationary inlet tube and is then smoothly accelerated by an inlet rotor. Centrifugal force immediately makes the solids build up on the wall of the bowl. The conveyor rotates in the same direction as the bowl, but at a different speed, thus moving the solids towards the conical end of the bowl. The solids leave the bowl through the solids discharge openings into the casing. Separation takes place throughout the entire length of the cylindrical part of the bowl, and the clarified liquid leaves the bowl by flowing over adjustable plate dams into the casing.

Gearbox Liquid Screw conveyor Wall of the bowl Inlet distributor Conical end Discharge port Feed tube Feed Solids Direct Drive Direct Drive is a unique system developed by Alfa Laval for automatic control of the differential speed between the bowl and the conveyor. This makes it easy to maintain the best possible balance between liquid clarity and solids dryness, irrespective of variations in the feed. Direct Drive comprises a new type of gearbox and variable frequency drive, which do not expose the bowl drive to parasitic braking power loss. The electrical installation is straightforward, power...

1 Declared A-weighted emission sound pressure level in free field over a reflecting plane at 1 m. distance from the decanter operating at maximum bowl speed, tested with water and closed outlet. STNX 418 STNX 438 STNX 944 STNX 706 Bowl diameter mm 353 (14 in) 480 (19 in) 575 (23 in) 740 (29 in) Max. bowl speed rpm 4000 3650 2900 2800 Max. G-force 3157 3574 2703 3243 Weight kg. 2200 (4840 lbs) 5000 (11000 lbs) 7000 (15400 lbs) 13000 (28860 lbs) Installed Power kW 15 – 37 45 – 110 75-160 132 – 250 (20 – 40 hp) (60 – 150 hp) (100- 200 hp) (150-300 hp) Sound Pressure Level1 dB(A) re. 20ìPa 82 85...

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