Tag Archives: compression loading

xxx A. Kabutey, D. Herak, C. Mizera and P. Hrabe
Theoretical analysis of force, pressure and energy distributions of bulk oil palm kernels along the screwline of a mechanical screw press FL 200
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Theoretical analysis of force, pressure and energy distributions of bulk oil palm kernels along the screwline of a mechanical screw press FL 200

A. Kabutey¹*, D. Herak¹, C. Mizera¹ and P. Hrabe²

¹Czech University of Life Sciences Prague, Department of Mechanical Engineering, Faculty of Mechanical Engineering, Kamycka 129, CZ165 00 Prague, Czech Republic
²Czech University of Life Sciences Prague, Department of Material Sciences and Manufacturing Technology, Kamycka 129, CZ165 21 Prague, Czech Republic
*Correspondence: kabutey@tf.czu.cz

Abstract:

The present study is a follow-up of the previously published study on the mathematical description of loading curves and deformation energy of bulk oil palm kernels under compression loading, aimed at determining theoretically the amounts of force, pressure and energy along the screw lamella positions 𝑆𝐿𝑝 of the screw press FL 200 by applying the tangent curve mathematical model and the screwline geometry parameters (screw shaft diameter, screw inner and outer diameters, screw pitch diameter and the screw thickness). The fitting curve value 𝐹𝑣 of the tangent mathematical model was further examined at 𝐹𝑣 = 2 and 𝐹𝑣 = 3 by identifying the force, deformation, stress and compression coefficients at varying vessel diameters 𝐷𝑣 and initial pressing heights 𝐻𝑡 of the bulk oil palm kernels. Based on the results of the stepwise regression analysis, the amounts of the theoretical deformation energy 𝑇𝐷𝐸 in linear pressing as well as the theoretical force 𝐹𝑟, pressure 𝑃𝑟 and energy 𝑆𝐿𝐸 of the screw press FL 200 were statistically significant (P-value < 0.05) or (F-value > significance F) in relation to the predictors (𝐻𝑡, 𝐷𝑣, 𝐹𝑣 and 𝑆𝐿𝑝). The coefficient of determination (R2) values between 61 and 86 % were observed for the determined regression models indicating that the responses 𝑇𝐷𝐸, 𝐹𝑟, 𝑃𝑟 and 𝑆𝐿𝐸 can accurately be predicted by the corresponding predictors. The normal probability plots of the responses approximately showed a normal distribution.

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1132–1137 Č. Mizera, D. Herák, P. Hrabě and T. Saller
Linear pressing of coconut copra meal (Cocos nucifera L.) under different temperatures
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Linear pressing of coconut copra meal (Cocos nucifera L.) under different temperatures

Č. Mizera¹*, D. Herák¹, P. Hrabě² and T. Saller¹

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Praha 6 Suchdol, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Kamýcká 129, CZ165 21 Praha 6 Suchdol, Czech Republic
*Correspondence: mizera@tf.czu.cz

Abstract:

Pressing of vegetable oils plays an important role in the food processing. This study described the compression behaviour of copra (Cocos nucifera L.) using the universal compression testing machine and vessel diameter of 60 mm with a plunger. The influence of heat treatment on oil recovery efficiency and specific mechanical energy were determined. Compression tests at the rate of 1 mm s−1 under five different temperatures 20, 40, 60, 80 and 100 °C were performed. The measuring range of force was between 0 kN and 50 kN. It has been found that the amount of obtained oil increased and specific mechanical energy decreased with increased temperature. Measured data were analysed by computer software Mathcad 14 (MathCAD 14, PTC Software, Needham, MA, USA). Mathematical model describing the mechanical behaviour of bulk copra under compression loading was represented.

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1906–1917 V. Kažimírová, Ľ. Kubík, J. Chrastina and T. Giertl
Determination of mechanical properties of poppy waste pellets
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Determination of mechanical properties of poppy waste pellets

V. Kažimírová¹*, Ľ. Kubík², J. Chrastina¹ and T. Giertl³

¹Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Building Equipment and Technology Safety, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
²Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Physics, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
³Slovak University of Agriculture in Nitra, Faculty of European Studies and Regional Development, Department of Regional Bioenergy, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
*Correspondence: viera.kazimirova@uniag.sk

Abstract:

The work deals with evaluation of mechanical properties three types of pellet samples produced from poppy waste. The pellets were submitted to compressive loading. The compressive loading curves of dependencies of force on strain and force on time were realised. Certain mechanical parameters were determined, namely the diameter of the sample, length of the sample, force at 10% of strain, force in the first maximum of the force – strain curve, strain in the first maximum of the force – strain curve, modulus of elasticity, force in the inflex point of the force – time and force – strain curves and strain and stress in the inflex point of the force – time and force – strain curves. The work lists correlations of mechanical parameters of individual pellet types. The pellet type 1 made only of ground poppy head mass has shown the best results, the pellet type 3 consisting of ground poppy heads after harvest and waste from sieving of poppy seeds in mass proportion 1 : 1 has shown the worst results.

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