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The hollow flighted screw dryer is an indirect heated dryer comprising of a rotating hollow flights. |
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Heat is transferred through the inner surfaces of the hollow flights and shaft. And since the principle of the conveyor is employed – the particles of the material within the mass are subjected to continuous movement and repeated contact with the surface containing the heat exchange agent. |
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The slow, rotation, conveying, interfolding and dispersing action increase the heat exchanged with the product. |
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The motion is however so mild and gentle that there is no dusting nor particle degradation. |
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The dryer is widely used for drying, cooling, heating and other operations where heat transfer is involved. |
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Heat transfer agents such as hot water, steam or hot oil provide for a wide range of processing temperatures. |
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Chief Advantages: |
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No direct contact with the heating medium |
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Close control of material as to temperature and time of treatment |
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One or all of the functions of heating, drying and cooling to be done continuously in the same unit |
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Heat transfer agent may be circulated either parallel or counter current to the flow of the material |
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Compact design is ideal for vacuum processing |
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Inert gas atmospheres readily maintained in material compartment |
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Sticky materials can be handled due to positive conveying action of multiple screws |
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