Introduction
As the name implies, continuous juice screening is effected on a wedge bar type screen fitted on a cylindrical drum mounted in horizontal position with appropriate slope towards non-drive end. Unlike in case of stationary parabolic screen the entire screening area provided in the rotary screen is fully utilized and hence maximum screening efficiency is achieved. The dynamic movement of screen allows utilization of smaller size wedge bar opening for removal of even the smallest bagacillo particles from mill juice. The diameter, the length of the screen, the speed of the rotating screen and its inclination are such designed that complete drainage of juice is ensured.

Operation The feed i.e. mill juice containing suspended solid particles comprising of fine bagacillo enters continuously from drive end of the drum through a distributor, the screened juice is collected in the slopping half cylindrical shape trough for quick removal of strained juice to strained juice receiving tank without causing any stagnancy which otherwise may provide a home for micro-organism. The solid mass keeps on rolling on the wedge bar screen and during its trajectile movement towards non-drive end the remaining juice is also screened away leaving the solid mass on the screen which is discharged in the existing screw conveyor OR directly on the inter-carrier/rake elevator of the mills.

Construction
A cylindrical rotary drum having 1800 mm dia. and length suitable to cane crushing capacity, in S.S. 304 construction is fitted with heavy duty rim located on either end for mounting the entire drum on trunnions. The screening area comprises of cylindrical shape wedge bar screen to form a rigid cylindrical shape rotary screen which forms an integral part of the rotating drum. Towards the driven end of the drum, the driving sprocket is rigidly fixed on output shaft of gear box and connected to driven sprocket mounted on rotating drum to transmit the power through heavy duty chain arrangement. Hydraulic Coupling is inserted in between motor and gear box input shaft so as to absorb the starting torque thereby ensuring longer life of the screen.. Two nos. thrust rollers fitted at the non-drive end absorbs the lateral thrust developed by inclined rotating drum. The motor is suitably covered to protect the same from splashing of juice. The entire assembly of the drum alongwith its trunnions is rigidly mounted on rugged Mild Steel fabricated frame for mounting the equipment on the staging structure in the mill house. The 4 nos. trunnion rollers on which screen drum rotates, is lined with metalone-6 non metallic material hence requiring no lubrication and each fitted with two nos. spherical roller bearings. Material of construction for Rotary Juice Screen drum, trough, juice inlet and side cover is S.S. 304. The cylindrical rotary screen assembly can either be mounted parallel or perpendicular to milling tandem adjacent to mills.

Screen Washing Arrangement
Washing system comprises of following :

»	High pressure wash water pump.
»	S.S. 304 flat cone spray nozzles are fitted at regular pitch on 80 NB hot water piped header. The spacing of the nozzles is such provided that the spray pattern caused due to specially designed split case nozzles ensures full coverage of screen to water spray.
»	Timer operated output relay gives signal to drive motor of flooded suction pump to automatically start the same to open hot water into hot water header at predetermined time interval which can be varied as desired.
»	This automatic operated screen washing is accomplished without stoppage of Screen.
»	Provision of one caustic soda solution re-circulation pump for periodical chemical cleaning of the screen alongwith drip header located at the top of the screen for removal of microbial growth.

Capacity and Sizing
Wide range in capacity and sizing is available such that, one single Rotary Juice Screen is suitable to handle mill juice for a plant capacity upto 10000 TPD

Advantages
With the recent introduction of better preparatory devices at milling station so as to achieve maximum mill extraction, it is observed that the mixed juice entering into process section contains higher quantity of finer bagacillo particles which subsequently affect the processing of juice. The separation of bagacillo particles at milling station itself, has twin advantages of reducing juice loading at second mill and avoiding processing problems. Viz.

»	Colour formation due to tea-brewing effect.
»	Interference with gravity sedimentation process at clarifier.
»	More retention time at clarifier for allowing ligher particles to settle.
»	Choking at juice strainers, pumps, piping, juice heater headers.

Salient features

»	Highest screening area per unit cane crushing capacity of the plant.
»	S.S. construction inclined bottom juice collecting trough in half cylindrical shape having amply sized outlet nozzle ensures quick removal of screened juice preventing stagnancy of juice at any corner to avoid built-up of micro organism colonies.
»	Drum rotates freely on four nos. trunnions each fitted in two sets of spherical roller bearings.
»	All four nos. trunnions are lined with Metalon-6 requiring no lubrication.
»	The lateral thrust is absorbed by two sets of thrust roller assembly at discharge end.
»	Hydraulic coupling in between motor and gear box ensures smooth starting and by avoiding starting jerk ensures longer life of screen.
»	Automatically operated wash water system with high pressure pump.
»	Caustic soda re-circulation system for removal of microbial colonies.
»	Virtually maintenance free, except periodical lubrication.