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DETERMINATION OF GRINDING ENERGY
THROUGH METHOD OF DYNAMIC TESTS AT
FRUITS WITH VARIABLE TEXTURE
Conference Paper
· August 2008
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Panainte Mirela
University of Bacau
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V. Nedeff
University of Bacau
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Mosnegutu Emilian
University of Bacau
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Retrieved on: 29 June 2016

12th International Research/Expert Conference
”Trends in the Development of Ma chinery and Associated Technology”
TMT 2008, Istanbul, Turkey, 26-30 August, 2008

DETERMINATION OF GRINDING ENERGY THROUGH METHOD
OF DYNAMIC TESTS AT FRUITS WITH VARIABLE TEXTURE

Mirela Panainte, Valentin Nedeff, Emilian Mosnegutu , Carmen Savin,
Bogdan M ăcărescu
University of Bacau, Faculty of Engineering, [anonimizat]
157 Calea Marasesti Street, Bacau 600115
Romania

ABSTRACT
A part of solid raw materials used in different industr ies but especially in food industry, assume this
grinding according to the technological requirement.
View the fact that grinding operation are complex how and the fact that products submissive to
grinding have property variable in time and space, method proposed for study was conceive so to take in consideration a lot of parameters.
Keywords: grinding, energy, texture

1. THEORETICAL CONSIDERATION
Dynamic test of vegetable products with variable texture have a quickly evolution, full of an
important impact on products processing [1, 2, ].
An important function at this type of test are c onstitute at determinati on of products abnormality
darkling under dynamic forces effect. To this effect was necessary to realizing cutting equipment with
the help which study the energy consum ption for different working conditions.
Cutting equipment (fig. 1.a) are constitute from carcass 1 in that interior are knife clip disc 2, mounted
so that to permit edge cutting setting to certain he ight over disc creating a controlled slot through
which go pieces of ripper products. Distance between edges cutting of knifes and knife clip disc
determine thickness of ripper pieces. On knife clip disc exist possibility to regulation the knifes angle
of incidence(fig. 1.b).Rotation of knifes disc are c hoice in function to product texture submissive to
grinding by cutting, the movement being transmit to one asynchrony motor with static frequency
changer 6, through the agency of driving belts 5. The cut products are feeding in equipment through removed lid 7 as which are attach pressure plate 8 which has roll to pressing product to knife surface, operation how can be realized with the help of springs 9, [5, 6, 8].

a) b)
Fig. 1. The scheme of cutting equipment.
a) the cinematic scheme of equipment; b) knife clip disc
889

The parameter studied – grinding energy – are dete rmined indirectly through measuring the torsion
moment which itself developed in shaft of cutting de vice, with the help of relation 1, demonstrate
theoretic [8]:

RMFt
m= ( 1 )

in which:
Fm represent the grinding force, N;
Mt – torsion moment, N·m;
l – distance between force direction and rotation axle (centre), m.

With value of this force, can be determined the grinding energy using the Rittinger relation,
particularized for vegetable products with variable texture:

⎟
⎠⎞⎜
⎝⎛− ⋅ ⋅ =D dS F En m R1 1 (2)

when:
Sn represent the surface new created for ideal particle, grinding after maxim diameter, m2;
D – particle dimension between the grinding, m;
d – particle dimension after the grinding, m.

View fact that grinding energy depends at surface new created, give to relation:

c p i nS N S S⋅+= (3)

when:
Si – particle surface submissive to grinding, m2;
Np – number of particles new formated
Sc – circle surface, m2.

Replacing relation 3 in relation 2, the equation of grinding energy become:

() ⎟
⎠⎞⎜
⎝⎛− ⋅ ⋅ + ⋅ =D dS N S F Ec p i tr R1 1 (4)

2. EXPERIMENTAL RESULTS
The experimental researches follow determination of grinding energy at vegetable products with
variable texture (fruits) through measuring the torsio n moment which are developed in developed in
shaft of cutting device, [3, 4, 7, 9].
In viewer realization the experiences was choices different sorts of fruits, in tables 1 and 2 are
presented the characteristics of sorts analyzed.

Table 1. Species and sort of fruit analyzed through torsion moment method.
Nr. crt. Species Sort Maturity Observation
1. Apple Jonangold Completely With peel
2. Apple Idared Completely With peel
3. Apple Grany Smith Completely With peel

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The grinding was realized with different type at knifes (right knife, sickle, type Z), was choose three
value of working revolution (300 rot/min, 450 rot/min, 650 rot/min) for which was calculated the
grinding energy.

Table 2. Middle hardness and humidity at fruits analyzed.
Nr. crt. Species Hardness (Fff) Humidity (%)
65 83,32
69 82,27 1.
Aplle
73 81,44

In figures 2 ÷ 4 are presented the variation of grindi ng energy function at working revolution for sorts
analyzed through different knifes type.

020004000600080001000012000
300 450 650
Working revolution (rot/m in)Grinding energy (J)
C1- right knif e C 2 – sickle knife C3 – knife type Z
010002000300040005000600070008000
300 450 650
Working revolution (rot/min)Gr i ndi ng energy (J)
C1 – right knife C2 – sickle knife C3 – knife type Z

Figure 2. Grinding energy variation in
function of revolution working for apples
from Grany Smith sorts for different type of
knifes. Figure 3. Grinding energy variation in
function of revolution working for apples
from Idared sorts for different type of
knifes.

010002000300040005000600070008000900010000
300 450 650
Working revolution (rot/min)Grinding energy (J)
C1 – right knife C2 – sickle knife C3 – knife type Z 020004000600080001000012000
65 69 73
Hardness (Fff)Grinding energy (J)
n=300 rot/min n=450 rot/min n=650 rot/min

Figure 4. Grinding energy variation in
function of revolution working for apples
from Ionangold sorts for different type of
knifes. Figure 5. Grinding energy variation in
function of hardness for fruit sorts
analyzed at different values of revolution
for sickle knife.

The grinding energy varying in function of product hardness at different values at revolution and for
different knifes type (fig. 5 ÷ 7).

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010002000300040005000600070008000
65 69 73
H ardness (F ff)Grinding energy (J)
n=300 rot/min n=450 rot/min n=650 rot/min 01000200030004000500060007000
65 69 73
H ardness (F ff)Grinding energy (J)
n=300 rot/min n=450 rot/min n=650 rot/min

Figure 6. Grinding energy variation in
function of hardness for fruit sorts
analyzed at different values of revolution
for knife type Z. Figure 7. Grinding energy variation in
function of hardness for fruit sorts
analyzed at different values of revolution
for right knife.

3. CONCLUSION
Behind of experimental experiences realized can be observed:
– grinding energy vary directly proportional with working revolution,
– grinding energy vary in function of knife type, so can be observed that bigger values at
grinding energy was obtained at grinding with the help of knife type Z<
– grinding energy vary in case of the same species in function of sort and at textural
characteristics of products.

4. REFERENCES
[1] Alvarez, M. D., Canet, W. & Lopez, M. E.. – Influence of deformation rate and degree of compression on
textural parameters of potato and apple tissues in texture profile analysis. European Food Research &
Technology, 215 (1), 13-20, 2002.
[2] Bourne, M.C., – Basic Principles of Food Texture Measurement. Lecture text of Dough Rheology and Baked Products Texture Workshop – Chicago, 1988.
[3] Earle R.L., – Unit operations in food industry, The New Zealand Institute of Food Science and
Technology, 1983.
[4] Harsfield B.C., Fridley R.B., Claypool L.L.,– Application of theory of elasticity to the design of fruit harvesting and equipment for minim bruising, Trans. of ASAE, (11) 4, 1972.
[5] Panainte Mirela, Emilian Mo șneguț u, Carmen Savin, coordonator Valentin Nedeff – M ărunțirea produselor
agroalimentare, Ed. Meronia, Rovimed Publishers, ISBN 973-8200-88-1, 973-7719-39-5, Bac ău, 2005.
[6] Panainte Mirela, Nedeff Valentin, Mosnegutu Emilian, Savin Carmen – Determination of griding energy through torsion moment measured from shaft of cutting device in case of tubercles and root crop legumes,
7
th International Conference Research and Development in Mechanical Industry, RaDMI 2007, Budva,
Montenegro Krusevac, Serbia, ISBN 86 -83803 -22-4, pg. 855-860.
[7] Panainte Mirela, Nedeff Valentin, Mo șneguțu Emilian, SAVIN Carmen, M ăcărescu Bogdan, Olaru Ciprian
– Determination of grinding energy to vegetable product through texture analysis method, MOCM 13,
volumul 3, ISSN 1224-7480, pg. 128- 134 Editura Alma Mater, Bacau 2007.
[8] Panainte Mirela – Cercetari privind optimizarea procesului de m ărunțire a produselor agroalimentare. Tez ă
de doctorat, Iasi, 2008.
[9] Sharma, S.K., Mulvaney, S.J., Rizvi, S.S.H. Material te sting and rheology of solid foods. In: Food process
engineering: theory and laboratory experiments (Ed. S. K. Sharma, S. J. Mulvaney, S. S. H. Rizvi) Wiley-
Interscience, pp 20-50, 1999.

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