Design experience and application – a continuing process of by luckboy


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115m3 continuous pan, boiling ‘after-product’ beet massecuite, Germany.

Design, experience and application – a continuing process of improvement
The FS continuous vacuum pan leads from start to finish and puts you in balanced control of the production of crystal sugar. A process of real continuity.
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Efficient use of energy with the ability to operate at very low calandria pressure Better massecuite exhaustion Improved crystal size distribution Simple and reliable automatic controls allowing very flexible operation without direct supervision High heat transfer rates and extended operating cycles means fewer units with consequent space saving and lower initial cost Reduced demand for steam and condenser water means smaller plant sizing

Station of ‘A’, ‘B’ and ‘C’ continuous pans of 140m3 each at new Indolampung Factory, Indonesia.

Leading the World in Sugar Technology


The FS continuous vacuum pan is the result of careful original research and testing by Tongaat-Hulett Sugar Ltd. in their high efficiency sugar mills in South Africa. The FS pan uses the proven advantages of a vertically tubed calandria to achieve high heat transfer coefficients. Because the massecuite flow path is designed to give good plug flow characteristics, the crystal size distribution is regular. The pan has been used to boil ‘A’, ‘B’ and ‘C’ cane raw massecuites and also for intermediate and after-product massecuites in the beet sugar industry. The knowledge gained by FS from the specific requirements of many applications has enabled us to improve the design so that optimum results can be obtained. The FS continuous vacuum pan can be supplied in either a single horizontal multi-compartment unit or, where very long operating cycles are needed, as a vertical stack of three or more distinct 4compartment units to allow for cleaning ‘on-the-run’. One 4-compartment unit in succession can then be taken out of service for cleaning leaving the other units operating.

The FS continuous vacuum pan is designed to operate at an extremely low massecuite head. Its unique sectional shape together with the very large downtake area gives superb circulation and consequently high rates of effective heat transfer. Therefore the pan can boil efficiently at quite small temperature differentials especially where massecuite viscosities are low. In turn this enables the use of lower pressure bled vapour giving greater overall steam economy in the production process. The FS continuous pan operating under steady-state conditions with a surge-free steam demand offers considerable economy in boiler and equipment sizing and in overall plant performance. This is in stark contrast to batch pans which start their operating cycle at much higher evaporation rates than at their final stage of ‘brixing-up’ and therefore must have steam/vapour pipes, condensers and injection water systems able to handle the highest rates. The FS continuous pan gives high quality consistent results and operators find that

Above left: 97m3 continuous pan at Le Gol Factory, Reunion. Above: Operator interface for 91m3 continuous pan at Gardel factory, Guadeloupe. Below: Stacked system of 3 x 40 m3 continuous pans at Spreckels Mendota, USA. Below left: Typical auto-feed liquor control with sight glass check system.



crystal size distribution usually improves from seed magma through to product crystal. The best results are obtained if the pan is fed with good quality seed magma and then the resulting continuous flow of high quality product can give substantial savings at the subsequent stage of crystal separation in the centrifugals – much less wash water and much less sucrose recirculation.




Fletcher Smith Limited, Norman House, Friar Gate, Derby DE1 1NU, England. Telephone +44 (0)1332 636000 Fax +44 (0)1332 636020 e-mail:

In accordance with our policy of progressive product development, we reserve the right to vary specifications without prior notice.

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