Precoppe, Marcelo ORCID: 0000-0002-7937-5782 (2020) Measuring pressure during cassava dewatering with a lifting bag. Manual. Natural Resources Insitute, University of Greenwich, London, University of Greenwich.

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Abstract

To process cassava into flour, the roots are peeled, grated, dewatered, pulverized, dried, and milled. Dewatering is the process where moisture content of the material is reduced by mechanical means. It is an important step for energy saving, as removing moisture by mechanical means consumes substantially less energy than by drying with hot air. Dewatering also impacts the quality of the final dried product, particularly the uniformity on the moisture content, as inconsistency on moisture reduction during dewatering propagates through drying. In small cassava processing enterprises dewatering is done with presses. The design and dimensions of those locally manufactured presses vary widely, but the large majority are hand-operated equipment using a lifting jack (Figure 1a) or a screw (Figure 1b) to exert the required force. To improve the consistency of the dewatering operation and consequently achieve the needed uniformity in the moisture content of the obtained pressed material, a dewatering protocol has been developed with a small cassava processing enterprise in Ghana, using a participatory approach. The aim was to define the steps and procedures needed to reliably achieve a moisture content of 40% on a wet basis. To accomplish this, the operators learnt that is important to always load the press with the same amount of material, exert always the same amount of force, and leave the material in the press always for the same amount of time. While controlling the amount of material and the amount of time proved to be easy, controlling the amount of force showed to be challenging, as those pressing equipment are devoid from any measuring instrument. Lifting bags are devices used for raising loads in industrial applications. It consisted of a heavy-duty rubber bag, a pneumatic hose for inflation, and a manometer for pressure monitoring (Figure 2). In the lifting operation, the deflated bag is inserted under the object to be raised. Air is pumped to the bag via the hose, the bag inflates, and the object is lifted (Figure 3). The aim of this work was to investigate the use of a lifting bag as a device to measure pressure during cassava dewatering.

Item Type:	Monograph (Manual)
Uncontrolled Keywords:	dewatering
Subjects:	S Agriculture > S Agriculture (General) T Technology > TJ Mechanical engineering and machinery
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Engineering & Science > Natural Resources Institute Faculty of Engineering & Science > Natural Resources Institute > Food & Markets Department
Related URLs:	Organisation
Last Modified:	16 Feb 2024 08:56
URI:	http://gala.gre.ac.uk/id/eprint/34869

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