INTRODUCTION
WHAT IS ALOE VERA
Aloe vera is a tropical plant known for its distinctive turgid, lace-shaped green leaves with jagged edges and sharp points Belonging to the lily family (Liliaceae) rather than the cactus family, Aloe vera is often mistaken due to its rosette-like leaf arrangement With over 300 species primarily found in Africa, Asia, and parts of America and Europe, Aloe vera L stands out as the "true Aloe vera" recognized for its extensive use and healing properties The plant produces two types of juice: a yellow latex extracted from the vascular bundles and a transparent mucilaginous gel from the inner pulp.
Aloe vera is widely cultivated across Vietnam, particularly thriving in the central and southern regions This versatile plant is primarily grown for its medicinal and cosmetic applications, flourishing best in full sunlight.
Figure 1.1: The shape of Aloe vera (Internet)
Aloe vera can grow up to 100 cm height, although most specimens are from 30 to
The plant reaches a height of 60 cm and features thick, fleshy leaves that grow in a rosette formation These leaves, which can measure between 30 to 60 cm in length and approximately 10 cm in width at the base, have serrated edges and originate from a central base The parenchyma cells within the leaves are rich in pulp, contributing to their robust structure.
Aloe vera plants can be harvested every 6 to 8 weeks by carefully removing 3 to 4 leaves per plant These leaves are sensitive to subfreezing temperatures, making weather conditions a crucial factor in the harvesting schedule To harvest, gently pull back the green leaf and cut at the white base, ensuring that the rind remains intact to protect the mother plant.
In biblical times, the Egyptains hailed Aloe vera as a plant of immortality Ancient Egyptain papyrus and Mesopotamian clay tablets described Aloe as useful in curing
Aloe vera is widely recognized for its medicinal properties, including its effectiveness in treating infections, skin issues, and serving as a natural laxative In many contemporary cultures, it continues to play a vital role in traditional medicine The Chinese refer to it as their "elixir of youth," describing the plant's skin and inner leaf lining as a cold, bitter remedy that promotes downward drainage and alleviates constipation caused by heat accumulation.
Aloe vera has been widely recognized for its significant contributions to human health, particularly in nutritional, pharmaceutical, and cosmetic applications This remarkable natural ingredient offers numerous benefits, making it a sought-after choice in the beauty industry Consequently, products derived from Aloe vera, including Aloe juice, yogurt, health drinks, and desserts, are gaining increasing popularity among consumers.
Figure 1.2: Some products from Aloe vera ( Internet)
2 Structure of Aloe vera leaf
2.1 Physical structure of Aloe vera leaf
The Aloe vera leaf is composed of three distinct layers: the outer rind, a thick protective layer made up of 15-20 cells that synthesizes carbohydrates and proteins; the viscous mucilage layer, where vascular bundles extend from the rind to facilitate transport; and the fillet proper, which maintains structural integrity with hexagonal structures that serve as the plant's water storage area.
Figure1.3: Physical structure of Aloe vera leaf [3]
2.2 Chemical composition of Aloe vera leaf
Aloe vera leaves contain several key components, including Aloin, which is an irritant laxative found in the yellow sap and is part of the Anthraquinone complex Another significant component is Methanol-Precipitable Solids (MPS), where approximately 20-25% of total solids precipitate when alcohol is added to Aloe solutions The primary chemical constituents of Aloe vera include polysaccharides, glycoproteins, and organic acid salts, with polysaccharides making up about 50-75% of the MPS, representing around 10-15% of the total solids Notably, there are over 200 different types of polysaccharides present in Aloe vera.
2.3 Biologically active chemical constituents of Aloe veraleaves
The gel from Aloe vera is composed of 98.5% water with a pH of 4.5 and contains active polysaccharides like Glucomannan and Acemannan Glucomannan serves as an effective moisturizer, commonly found in various cosmetic products, while Acemannan, the primary carbohydrate in the gel, is a water-soluble long-chain mannose polymer known for its ability to accelerate wound healing, enhance immune function, and provide antiviral benefits.
Table 1.1: Major medical compositions of Aloe vera [3]
Pure mannan, acetylated mannan, acetylated glucomannan, glucogalactomannan,galactan, galactogalacturan, arabinogalactan, galactoglucoarabinomannan, pectic substance, xylan, cellulose
93 % Mannose ( 3 % glucose, 3% galactos, 1% arabinos), 95 % free glucose (fructose, galactose)
Monosaccharides: Glucose, Fructose, Mannose, L-rhamnose and aldopentose Polysaccharides: glucomannans/ polymannose
It provides 12 anthraquinones, which are phenolic, compounds, traditionally
Provides aloin A and B (or collectively known as barbaloin), isobarbaloin, anthranol, anthracene, ester of cinnamic acid, aloe emodin, emodin, chrysophanic known as acid , etheral oil, resistannol, aloetic acid
It contains 13 enzymes Aliiase, cellulase, peroxidase, alkaline phosphatase, amylase, carboxypeptidase, catalase, cyclooxidase, cyclooxygenase, lipase, phosphoenolpyruvate carboxylase, superoxide dismutase, bradykinase
Provides 20 of the 22 required amino, acids and 7 of the 8 essential ones, and 20 % Arg
Alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, hydroxyproline, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tyrosine, valine,
Another classes Glucose, mannose, rhamnose, adopentose,
PRACTICAL SIGNIFICANCE OF PROJECT
This project focuses on researching Aloe vera peeling machines both in Vietnam and globally As the output of this system serves the food industry, it is essential to prioritize food safety.
We have analyzed real processing techniques, gathered insights from employees experienced in peeling Aloe vera leaves, and researched various Aloe peeling machines on the market Our goal is to manufacture a more efficient and cost-effective machine that enhances the peeling process.
Biological activity loss in gels is primarily caused by microbial decay, which begins when leaves are harvested from the plant If the base of the leaves is not properly sealed, it significantly increases microbial counts, leading to a notable reduction in the product's biological activity Additionally, the rind of the leaf serves as another significant source of microbial contamination.
Harvesting Aloe vera leaves requires careful cleaning to remove dirt and impurities It is essential to eliminate the yellow fluid secretion from the leaves, ensuring that the prolayer beneath the green rind is intact while avoiding the vascular bundles Additionally, both the top and bottom rinds should be carefully cut away to prepare the leaves for use.
Once peeled, Aloe vera is diced to facilitate subsequent processes like the production of Aloe yogurt, health drinks, and juice This method not only saves time but also enhances preservation and transportation efficiency.
The project addresses real-world demand, offering extensive practical applications If implemented, it will significantly reduce the time-consuming peeling process With a capacity of 5000 kg/h, the peeling efficiency will be greatly enhanced, ensuring a continuous operation.
To solve this problem, “Aloe vera peeling and dicing system” is done with the objective of 5000(kg/h).
PROJECT OBJECTIVES
The project aims to create an "Aloe Vera Peeling and Dicing System" to address the food needs in Vietnam and enhance international export opportunities Additionally, it offers valuable experience for researchers by applying mechanical knowledge to design and develop a versatile machine with broad applications.
The "Aloe Vera Peeling and Dicing System" is designed to process 5,000 kg/h of Aloe vera leaves After the peeling process, the leaves are transferred to the dicing stage, where they are cut into pieces measuring approximately 3-5 mm The system is constructed using stainless steel for durability and hygiene.
6 to fabricate the the main components of the “Aloe vera peeling and dicing system to meet the safety food product standard
The project aims to design and develop a comprehensive mechanism for processing Aloe leaves, which includes loading, peeling, and dicing systems The mechanical design will facilitate the peeling and dicing of Aloe leaves into various sizes, utilizing a conveyor and leaf-leading roller to guide the leaves into the peeling mechanism for rind and fillet removal Subsequently, the processed Aloe will be directed to a dicing mechanism featuring horizontal and vertical cutting rollers, which are adaptable for size adjustments and cutter replacements Additionally, the design emphasizes ease of assembly and cleaning to ensure food safety The project also includes the development of a control system comprising a control board and control panel for efficient operation.
The scopes of “Aloe vera peeling and dicing system” are loading mechanism, peeling mechanism, Aloe dicing mechanism and some elecctrical equipments.
SOMES PEELING PROCESSES OF ALOE MACHINE
Automatic top and bot rind peeling
Aloe leave after being trimmed top and bot
Figure 1.4: Some Aloe peeling processes flowchart
THE SYSTEM OF ALOE VERA PEELING MACHINE
This project is designed to develop a machine with all automatic steps from loading, filleting, peeling rind to dicing
Automatic top and bot rind peeling
Aloe vera leaf after being trimmed top and bot
Figure 1.5: Flowchart of Aloe vera peeling and dicing system of this project
THE RESEARCHES RELATING TO THE PROJECT
The products from the Aloe vera is very famous in Europe, India and China There are some Aloe vera peeling machines which is used in the market
The Aloe vera peeling machine from TecnoTrans-Sa, a German company, utilizes a conveyor-belt and roller system to efficiently peel the surfaces of Aloe vera leaves After trimming the butts and tips, the leaves are fed into the machine for peeling, with the upper face processed first, followed by the other side in subsequent steps The handling of the Aloe vera leaves is supported by employees, highlighting the importance of their role in the peeling process.
Figure 1.6: Aloe peeling machine of TecnoTrans-Sa company (Germany)
The Aloe peeling machine from Mexico operates on a rolling principle, where employees support the Aloe vera leaves After trimming the butts, tips, and fillets, the leaves are fed into the machine, where two rotating rollers guide them to the peeling mechanism This process efficiently separates the inner gel from the outer rind, which is collected in a container beneath the machine The machine has an impressive processing capacity of approximately 500 kg per hour, depending on the workforce involved.
Figure 1.7: Aloe peeling machine of Mexico
The Aloe vera peeling machine from Xingtai City Judu Commercial in China efficiently processes trimmed aloe leaves by placing them on a conveyor belt As the leaves advance, they are positioned between the conveyor and a cutting mechanism, ensuring precise peeling for optimal processing.
9 cutter, the Aloe rind will be peeled The Aloe leaves is supported by employees and the effect is about 1-1,5 ton/hr (according to the information of the Producer)
Figure 1.8: Aloe peeling machine of Xingtai City Judu Commercial (China)
In Vietnam, there is a lack of research and application of Aloe peeling and dicing machines in the manufacturing sector Although some Aloe peeling machines are produced in China, their adoption is limited due to a high wastage rate.
THE NECESSARY OF PROJECT
The manufacturing potential of Aloe products is significant; however, the complex Aloe processing involves numerous steps, requiring a substantial workforce and machinery, which complicates the assurance of food safety.
The hand filleting method for processing Aloe leaves was created to prevent contamination of the internal fillet with yellow sap This technique involves carefully removing the rind with a sharp knife, which helps maintain low anthraquinone levels, although much of the mucilage ends up on the working surface During the process, the lower 25 mm of the leaf base, the tapering point at the top (50-100 mm), and the sharp spines along the leaf margin are cut away The knife is then inserted into the mucilage layer beneath the green rind to effectively remove both the top and bottom rinds.
Figure 1.9: Peeling Aloe vera by hand
The demand for Aloe products is rapidly increasing, leading to a surge in raw material availability, ensuring a steady supply for continuous manufacturing While there are Aloe peeling machines available from China, their high wastage rates limit their widespread adoption Currently, employees manually process Aloe leaves, transferring the inner gel to separate machines for dicing The efficiency of Aloe peeling machines from India, China, and Europe remains low due to the reliance on manual labor for filleting Aloe vera leaves.
In Vietnam, there is a lack of research and application of Aloe peeling and dicing machines in manufacturing processes As a result, many businesses, including Viet Nam Dairy Products Joint Stock Company and Nutifood Joint Stock Company, rely on a significant number of employees for this task.
There are over 300 species of Aloe [1], but Aloe vera L (Aloe vera) is called the
“real Aloe vera” planted in Viet Nam – Figure 1.10
Figure 1.10: Aloe vera which is planted in Ninh Thuan Province
Accoding to the demand of manufacturing Aloe peeing system, the project is researched to design and develop a Aloe peeling and dicing system
MECHANICAL DESIGNING
ENERGY THEORY OF FRACTURE FOR AN LASTIC FILM-KENDALL’S MODEL
In 1975, Dr Kendall introduced a model in his article "Thin-film peeling-the elastic term," which analyzed how various factors affect peeling strength through energy balance in a system comprising a thin elastic film and a rigid substrate The experimental setup is illustrated in Figure 2.5, detailing parameters such as film thickness (d), width (b), displacement (Δl), elastic modulus (E), peeling angle (θ), and the applied force.
Figure 2.5: Schematic of the peeling-off system
Elastice adhesive thin film, modul G
Dr K Kendall's research identifies three categories of energy change during the peeling process The first category pertains to surface energy change, which corresponds to the energy needed to create new surfaces To facilitate analysis, a new variable called adhesive energy (R) is introduced, representing the energy required to create new surfaces per unit area Consequently, the surface energy can be articulated in Equation (2.1).
It should be noted that R is the dependent on peeling rate
The second term refers to a change in potential energy, which results from the work done by the peeling force Assuming that the adhesive film is not extensible, the potential energy change can be calculated by multiplying the peeling force by its displacement in the direction of that force.
So the potential energy change can be expressed in Equation (2.2)
In the peeling process, the adhesive layer behaves elastically, gradually extending as the force is applied This results in an additional energy change component related to the elastic deformation For simplification in calculations, we consider the region AB, which stretches by a length of Δl under the influence of the peeling force The elastic energy change can be divided into two components, with the first part representing the work done by the peeling force within the stretching region AB, as outlined in Equation (2.3).
When region AB is stretched, it stores energy, similar to a spring According to Hooke's Law, the energy stored in the extended region can be represented by Equation (2.4).
So the overall value of the elastic energy change is:
Elastic modulus is the ratio of stress and strain Accding to this defination, we can conclude the relation ship between elastic modulus G and l
Equation (2.6) and (2.7) can be conbined, so the elastic energy change can be expressed in Equation (2.8)
DESIGNING THE PEEING MECHANISIM
Aloe vera leaves are first cleaned and trimmed before being placed on a conveyor belt, where they are directed into a filleting mechanism The leaves then pass through a peeling mechanism consisting of two parallel rollers that rotate in opposite directions at the same speed These rollers, designed with variable apertures, accommodate the varying widths and thicknesses of the leaves The elasticity of the inner gel allows the flexible rollers to create a rectangular cross-section before the leaves reach the cutter The weight of the flexible rollers is carefully calculated to ensure proper contact with the cutter; if too light, the leaves won't be peeled completely, while if too heavy, they may become deformed To optimize performance and minimize machine size, three mechanisms are integrated into the roller assembly.
Figure 2.7: Crossing section of Aloe after passing the rollers
The design calculations for the machine's components are based on a processing capacity of 5000 kg/h and the dimensions of Aloe vera leaves, which were measured to have an average length of 495 mm, width of 80 mm, and thickness of 28 mm According to Wang and Strong (1993), the average weight of individual Aloe vera leaves ranges from 390 to 700 g, with lengths between 480 and 600 mm, widths from 89 to 115 mm, and optical densities varying from 1.020 to 1.437 (abs).
Three flexible rollers are used separately for three peeling mechanism The diameter of the flexible roller is decided on the basis of length of leaf
To maintain a continuous flow and prevent blockages caused by excessive leaves, the design calculations for Aloe vera were based on an average leaf length of 495 mm, derived from a sample of 50 leaves.
Considering the 10 mm margin and 495 mm leaf length, the diameter of movable roller is calculated on the basis of length as periphery of roller [4]
Figure 2.9: The gap of two rollers
The periphery of the flexible roller: P G D G (2.9) When D G = diameter of flexible roller and the average weight of Aloe vera leaf is 500 g
The calculated diameter of flexible roller will be taken as D 150( mm )
To reduce the weight of the roller but still have enough force, choose:
To ensure a continuous flow and prevent blockage caused by excess Aloe vera leaves, the length of the roller was designed to be twice the width of the average Aloe vera leaf, which measures 80mm This design choice effectively minimizes the risk of leaf obstruction during operation.
L c mm According to [4], the length of the roller is:
The calculated length of flexible roller will be taken as L c 160(mm)
Figure 2.10: The distance of two rollers
The gap between two rollers will be taken as 25% less than the thickness of the Aloe vera leaf (28mm) to keep Aloe vera leaf passing easily through two rollers [4]
The clearance between rollers is 28 75 21( ) 20( )
The calculated gap between two rollers will be taken as 20 mm
Figure 2.11: The structure of flexible roller
The dimensions of roller is determined as follows:
The dimensions of the flexible roller are shown in Fig.2.11
Figure 2.12: The dimensions of flexible roller
The power of the motor is determined as follow: ct P t
P ct : The necessary power of motor (kW)
P t : Calculated power of working (kW)
Where: d = 0.95: The effect of belt drive
ol =0.99: The effect of a pair of gearings (table 2.3 [7])
The necessary power is given according to the calculated power Pt
The calculated power is given by:
The working power is given by: lv 1000
Where: P lv : The power of roller (kW)
V (m/s), m = weight of Aloe leaf (kg), a = 10 (m/s 2 ) [6]
P lv P ro ller (2.13) Where: P roller : the power of flexible roller
Calculating the flexible roller power:
The dimensions of the keyway:( L W H ) : 0.015 0.006 0.003( ) m
Specific weight of 304 stainless stell: inox 7930 ( kg / m 3 )
Aloe total drag Aloe total drag
The necessary power is given by:
There are three peeling mechanism to meet the need of 5000 kg/hr, so the effect of each peeling mechanism is determined as follows:
The average weight of an Aloe vera leaf is 0.5 kg, allowing for efficient peeling in just one second With a roller diameter of 150 mm, the roller covers an average length of approximately 471.2 mm per second during the peeling process.
Based on the real condition and the environment, the calculated speed of roller will be taken as n 150( rpm )
Choose Motor : 4AA56A4Y3 (table 1.3 [7]) Perameter: P motor 0.12 ( kW ) n motor 1380 rpm c os 0.6 6
Where : n motor : The number of revolutions of motor n working : The number of revolutions of roller
So the transmission of geae motor will be taken as u gear motor 4.6
4.6 0 ( ) gear motor gear m moto otor n r n rpm
2 gear moto roller belt n r n rpm
0.08 0.1( ) 0.9 gear motor gear m motor otor
2546.67( ) 300 gear motor gear motor gear motor
4.2 The parameters of chain transmission
The number of teeth of smaller gear will be taken as: z 1 28
The number of teeth of bigger gear is varified by the relationship:
Class Motor Gear motor Roller
Transissions ratio u u gear motor 4.6 u chain 2
Straind roller chain with pitch of chain: p 12.7( mm ) (table 5.5 [7]) is choosen to satisfy: t 3.98
P P and P P max (table 5.8 [7]) Roller distance:
The number of chain link:
The calculated number of chain link will be taken as x120
Where: n 200 rpm (table 5.10 [7] ), s 9,3 s s : The chain drive is satisfied
The coordinate system is considered as below: z x y
Figure 2.14: The coordinate system for calculating flexible roller
Figure 2.15: Load diagram of flexible roller
Using moment equation and vector projection in ZOX and ZOY plane:
The moment diagram for the roller:
Figure 2.16: The moment diagram of flexible roller
Base on the the toughness, fit and technology, the roller diameters are taken as:
5.3 Safety factor at roller sections
According to the structure of roller and moment diagram, the dangerous sections need to be tested are:
The dimensions of keyway, value of moments is shown in the below table:
Table 2.2:Dimensions of keyway, value of moments at dangerous sections
Section Roller diameter Bxh t 1 W mm j ( 3 ) W o j (mm 3 ) a j a j mj
The rollers are manufactured on the turning machine, so the dangerous sections must satisfy: R a 2.5 0.63 ( m), stress concentration factor to surface states: x 1.06
K d , are shown on the table below:
Table 2.3:The parameters at dangerous sections
S 2,5 so the roller hardness testing is not necessary
The bearing load is determined as follows:
So single row ball bearings is choosen
Choose 206-R series single row angular contact ball bearings
Inside diameter: d 30 ( mm ), basic dynamic radial load rating: C 15.3 ( kN ),
Basic static radial load rating C o 10.2(kN)
6.2 Basic dynamic radial load rating
Dynamic load is given by:
K : the factor affected by temperature đ 1
Basic dynamic radial load rating is satisfied
6.3 Basic static radial load rating
The value design basic static radial load rating should sastify:
Where: C0 : Basic static radial load rating
Basic static radial load rating is satisfied
DESIGNING THE FILLET MECHANISM
Fixed roller is used for three peeling mechanisms Dimensions of the fixed roller is follow the flexible roller, except the length
Considering the length of fixed roller as the double of the length of 3 flexible rollers and 25% extra margin to prevent blocking of leaf [4]
The length of fixed roller is determined as follows:
L2 3 60 25% 3 160 1200 (mm)The dimension of the fixed roller will be taken as L 1310( mm )
Figure 2.18: Dimensions of fixed roller
2.2 Designing the leaf-leading roller
The structure and dimensions ofleaf-leading roller is the same as the fixed rooler
The power of the motor is determined as follow: ct P t
P ct : the necessary power of motor (kW)
P t : calculated power of working (kW)
Where: x = 0.95: the effect of chain transmission
ol =0.99: the effect of a pair of gearings (table 2.3 [7]) The necessary power is given according to the calculated power Pt
The calculated power is given by:
The working power is given by: lv 1000
Where : P 1 : Power of fixed roller
P 2 : Power of leaf-leading roller
3.1.1 Calculating the power of fixed roller:
The number of fixed roller : 1
Figure 2.19 : Dimensions of fixed roller
Specific weight of 304 stainless steel: stainless steel = 7930 (kg/m 3 )
3.34 10 3 7930 26.5 total total stainless steel m V kg
The force is considerd as:
Aloe roller drag Alo e total dr g a
3.1.2 Calculating the power of leaf-leading roller
The number of fixed roller : 1 The dimensions and structure of leaf-leading roller are the same as fixed roller so:
3.1.3 Calculating the power of conveyor
The diameter of conveyor roller: d 75( mm ):
Figure 2.20: The dimensions of conveyor roller
Specific weight of 304 stainless steel: stainless steel = 7930 (kg/m 3 )
1.15 10 3 7930 9.12 total total stainless steel m V kg
The force is considerd as:
Aloe roller drag Aloe to tal drag
Parameters: P motor 1.1 kW n motor 1400 rpm osc = 0.81
The design value of system trassission ratio is given by:
n Where: motor n : the number of revolutions of motor n lv : the number of revolutions of working roller Where: chain1 u =2, u chain2 2
3.2.2 Parameters of chain transmission a Rotation
0.83( ) 0.95 0.99 0.95 0.99 0.95 0.99 gearings chain gearings chain gearing gea s chain r motor
Table 2.4: Parameters of chain transmission of fillet mechanism
Transmission ratio u gearmotor 4.67 u u chain 1 2 u chain 2 2 u chain 3 1
The number of revolutions n (rpm)
4.2 The parameters of chain transmission
The number of teeth of smaller gear will be taken as: z 1 28 [7]
The number of teeth of bigger gear is varified by the relationship:
Straind roller chain with pitch of chain: p 12.7( mm )(table 5.5 [7]) is choosen to satisfy: t 3.98
P P and P P max (table 5.8 [7]) Roller distance:
The number of chain link:
The calculated number of chain link will be taken as x 1 120, x 2 120, x 3 110,
Where: n 300 rpm ( table 5.10 [7] ), s 9.3 s s : The chain drive is satisfied
5 Fixed roller and leaf-leading roller test
The coordinate system is considered as below: z x y
Figure 2.21: The coordinate system for calculating fixed roller
Figure 2.22:Load diagram of fixed roller
Using moment diagram and vector in ZOX and ZOY plane for calculating:
Moment diagram for the roller:
Figure 2.23:Moment diagram of fixed roller
Base on the the toughness, fit and technology, the roller diameters are taken as:
5.3 Safety sections in some sections
Base on the roller structure and moment diagram, the sections need to be tested are:
The demensions of keyway, the value of moments is in the below table:
Table 2.5: The dimensions of keyway, the value of moments at dangerous sections
Section Roller diameter B h t 1 W mm j ( 3 ) W o j (mm 3 ) a j a j mj
The rollers are manufured on the turning machine, so the dangerous sections must satisfy: R a 2.5 0.63 ( m ), stress concentration factor to surface states: x 1.06
, K d , are shown on the table below:
Table 2.6: The parameters at dangerous sections
S 2.5 so the roller hardness testing is not necessary
So single row ball bearings is choosen
Choose 206-R series single row angular contact ball bearings
Inside diameter d 30 mm, basic dynamic radial load rating: C 15.3 ( kN ) , basic static radial load rating: C o 10.2 ( kN )
6.2 Basic dynamic radial load rating
Basic dynamic radial load rating is satisfied
6.3 Basic static radial load rating
Basic static radial load rating should satisfy:
Where: C0 :Basic static radial load rating
ALOE VERA DICING MECHANISM
Aloe dicing mechanism includes 2 rollers: vertical cutting roller and horizontal cutting roller as as Fig 2.16:
Disk-shaped cutters are mounted on the vertical cutter, allowing for adjustable Aloe dice sizes by changing the ring sizes (δ) placed between the cutters, as illustrated in Fig 2.17.
Figure 2.25: Aloe vertical cutting priciple
Rectangle cutters are mounted on a horizontal roller, allowing for adjustable Aloe dice sizes by modifying the cutter distance or the roller's revolutions The principle of horizontal cutting for Aloe is illustrated in Fig 2.16.
Figure 2.26: Aloe horizontal cutting principle
2 Design the vertical cutting roller
The roller width is determined by the measurement of three Aloe vera leaves, with an additional 25% allowance to facilitate smooth passage through the two rollers To avoid leaf blockage, the vertical cutting roller's revolutions are matched with those of the flexible roller.
Figure 2.28:Dimensions of vertical cutting roller
3 Design the horizontal cutting roller
The horizontal cutting roller is designed to match the length of the vertical cutting roller; however, its number of revolutions is calculated to be five times greater than that of the vertical cutting roller, based on the roller's structural design.
Figure 2.30: Dimensions of horizontal cutting roller
The power of the motor is determined as follow: ct P t
P ct : The necessary power of motor (kW)
P t : Calculated power of working (kW)
Where: x = 0.95: the effect of chain transmission
ol =0.99: the effect of a pair of gearings (table 2.3 [7]) The necessary power is given according to the calculated power Pt
The calculated power is given by:
The working power is given by: lv 1000
P P P Where : P 1 : Power of vertical cutting roller
P 2 : Power of horizontal cutting roller
To reach the effect 5000(kg/hr), the number of revolutions of vertical cutting roller is as the number of revolutions of flexible n 150( rpm )
The number of revolutions after being calculated base on the structure of 2 roller is taken 5 times as the number of revolutions of vertical cutting rolller
4.52 10 4 7930 3.59 total total stainless steel m V kg
Working force is determined as follows:
1.16 10 3 7930 9.18 total total stainless steel m V kg
Aloe total drag Aloe total d rag
Parameters: P motor 0.37 kW n motor 1365 rpm osc = 0.69
The design value of system trassission ratio is given by:
n Where: motor n : the number of revolutions of motor n n : the number of revolutions of horizontal cutting roller n lv : the number of revolutions of vertical cutting roller Where: chain2 u =1
4.2.2 Parameters of chain transmission a Rotation
750 150( ) d 5 cha gear in motor n n rpm
750 750( ) n 1 cha gear in motor n n rpm
0.31( ) 0.95 0.99 0.95 0.99 gearings chain ol x gear motor
3947.33( ) 750 gear motor gear motor gear motor
Table 2.7: The parameters of chain transmission of dicing mechanism
5.2 The parameters of chain transmission
The number of teeth of smaller gear will be taken as: z 11 21, z 12 28
The number of teeth of bigger gear is varified by the relationship:
The number of revolutions n (rpm)
Straind roller chain with pitch of chain: p 12.7( mm )(table 5.5 [7]) is choosen to satisfy: t 3.98
P P and P P max (table 5.8) Roller distance:
The number of chain link:
The calculated number of chain link will be taken as x120
Where: n 800 rpm (table 5.10 [7]), s 10.2 s s : The chain drive is satisfied
The coordinate system is considered as below: z x y
Figure 2.37:The coordinate system for calculating vertical cutting roller
Figure 2.38:Load diagram vertical cutting roller
Using moment diagram and vector in ZOX and ZOY plane for calculating:
Moment diagram for the roller:
Figure 2.39:Moment diagram of vertical cutting roller
Base on the the toughness, fit and technology, the roller diameters are taken as:
6.3 Safety sections in some sections
Base on the roller structure and moment diagram, the sections need to be tested are:
- Belt-assembly section (10) in Table 2.8
- Bearings-assembly section (11) in Table 2.8
The demensions of keyway, the value of moments is in the below table:
Table 2.8: The dimensions of keyway, the value of moments
Section Roller diameter B h t 1 W mm j ( 3 ) W o j (mm 3 ) a j a j mj
12 40 6 x 6 3.5 5580.57 11860.57 2.26 0.22 The rollers are manufured on the turning machine, so the dangerous sections must satisfy: R a 2.5 0.63 ( m), stress concentration factor to surface states: x 1.06
, K d , are shown on the table below:
Table 2.9: The parameters of some dangerous sections
S 2,5 so the roller hardness testing is not necessary
So single row ball bearings is choosen
Choose 206-R series single row angular contact ball bearings
Inside diameter d 30 mm, basic dynamic radial load rating: C 15.3 ( kN ), basic static radial load rating: C o 10.2 ( kN )
7.2 Basic dynamic radial load rating
Basic dynamic radial load rating is satisfied
7.3 Basic static radial load rating
Basic static radial load rating should satisfy:
Where: C0 :Basic static radial load rating
The coordinate system is considered as below: z x y
Figure 2.40:The coordinate system for calculating horizontal cutting roller
Figure 2.41: Load diagram of horizontal cutting roller
Using moment diagram and vector in ZOX and ZOY plane for calculating:
Moment diagram for the roller:
Figure 2.42:Moment diagram of horizontal cutting roller
Base on the the toughness, fit and technology, the roller diameters are taken as:
8.3 Safety sections in some sections
Base on the roller structure and moment diagram, the sections need to be tested are:
The demensions of keyway, the value of moments is in the below table:
Table 2.10: The dimensions of keyway, the value of moments at dangerous section
Section Roller diameter B h t 1 W mm j ( 3 ) W o j (mm 3 ) a j a j mj
The rollers are manufured on the turning machine, so the dangerous sections must satisfy: R a 2.50.63 ( m), stress concentration factor to surface states: x 1.06
, K d , are shown on the table below:
Table 2.11: The parameters at dangerous sections
S 2,5 so the roller hardness testing is not necessary
So single row ball bearings is choosen
Choose 206-R series single row angular contact ball bearings
Inside diameter d 30 mm, basic dynamic radial load rating: C 15.3 ( kN ), basic static radial load rating: C o 10.2 ( kN )
9.2 Basic dynamic radial load rating
Basic dynamic radial load rating is satisfied
9.3 Basic static radial load rating
Basic static radial load rating should satisfy: t 0
Where: C0 :Basic static radial load rating
DESIGNING THE CUTTER
The thickness of Aloe vera leaf: h = 2,8 0, 05 0, 08 h
Material of tool: 304 stainless steel
The angle of calculation will be taken as o 16 o
The calculated angle will be taken as 5 o
Cutting force is determined as follows:
DESIGNING THE LEAF-FEEDING CONVEYOR-BELT
= 0.61: specific weight of material (ton/m 3 ) s =0.15 [9]
Minimum rotation of conveyor-belt is given by:
The calculated ratation will be taken as n 300( rpm )
The conveyor speed is given by:
The necessary power is determined as follows:
Base on the the size of the machine and type of material, the width of the conveyor- belt will be taken as B = 1000 mm (table 1 [9])
Figure 2.47 : The forces on conveyor [9]
P: The power (kW) V: conveyor-belt speed (m/min)
0.03: friction factor between belt và pulley (table 16 [9])
TECHNOLOGY PROCEDURE
DESIGNING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING
The manufacturing steps are shown in the below table:
Table: 3.1 Technology procedure of flexible roller
1 st manufacturing step: facing and center drill
2 nd manufacturing step: facing and center drill
3 rd manufacturing step: straight turning 40
4 th manufacturing step: straight turning 20, 30
5 th manufacturing step: straight turning 30
6 th manufacturing step: keyway milling
8 th manufacturing step: straight turning 150
DESIGNING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING THE
The manufacturing steps are shown in table below:
Table 3.2: Technology procedure of fixed roller
1 st manufacturing step: facing and centre drilling
2 nd manufacturing step: facing and centre drilling
3 rd manufacturing step: straight turning 40
4 th manufacturing step: straight turning 30, 20
5 th manufacturing step: straight turning 30
6 th manufacturing step: keyway milling
8 th manufacturing step: straight turning 150
DESIGING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING THE
The manufacturing steps are shown in table below
Table 3.3: Technology procedure of vertical cutting roller
1 st manufacturing step: facing and drill milling
2 nd manufacturing step: facing and drill milling
3 rd manufacturing step: straight turning 40
4 th manufacturing step: straight turning 26, 20
5 th manufacturing step: straight turning 26, 20
6 th manufacturing step: external threadingM24
7 th manufacturing step: face milling
8 th manufacturing step: keyway milling
DESIGING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING THE
MANUFACTURING THE HORIZONTAL CUTTING ROLLER
The manufacturing steps are shown in table below:
Table 3.4: Technology procedure of horizontal cutting roller
1 st manufacturing step: facing and centre drilling
2 nd manufacturing step: facing and centre drilling
3 rd manufacturing step: straight turning 30
4 th manufacturing step: straight turning 26, 20
5 th manufacturing step: straight turning 26, 20
6 th manufacturing step: straight turning 24
7 th manufacturing step:external threading M24x3
8 th manufacturing step: facing milling
9 th manufacturing step: keyway milling
DESIGN OF ELECTRICAL RECRUIT
CONTROLL SYSTEM
Figure 4.1: Block diagram of controll system
ELECTRICAL RECRUIT
In v er te r 1 In v er te r 2
Figure 4.2: Aloe vera electrical recruit
ELECTRIC DEVICES
PRINCIPLE OF OPERATION CONTROLL CIRCUIT
Pressing S1 activates K0, Inverter 1, Inverter 2, and H0 The motors are engaged when S3, S5, S7, S9, or S11 are pressed, while pressing S4, S6, S8, S10, or S12 turns the motors off To halt the entire system, press S2 Additionally, R1 and R2 can be used to adjust the motor speeds.
RESULT AND DISCUSSION
PARTS
Figure 5.1: Aloe vera vertical cutting roller
Figure 5.2: Aloe vera horizontal cutting roller
Figure 5.3: Aloe vera dicing mechanism
RESULT
Figure 5.9: Aloe vera peeling and dicing system
The newly designed Aloe peeling and dicing system achieves 99% of its objectives, successfully removing the rind with a capacity exceeding 5000 kg/hr This innovative system is engineered to efficiently process Aloe, meeting the targeted capacity requirements.
Figure 5.10: Aloe vera after being peeled
Figure 5.11: Results after being diced
After being done research with three peeling mechanisms, there are 56 Aloe leaves are peeling after 20 seconds, so the capacity is: 0,5x56x3x60 = 5040(kg/h)
The average weight of an Aloe vera leaf is 500 grams, while experiments on a 50 kg Aloe vera plant revealed that the average weight of its inner gel is 432 grams The optimal dimensions for Aloe vera are 8x8x8, and following design and development efforts, we achieved significant results.
Figure 5.12 : Size and weight of Aloe vera dice per a leaf
Aloe vera dice exhibit nearly equal length and width, but their height varies significantly The unique shape causes the bottom of the Aloe vera to be much deeper than the top, resulting in a weight distribution that decreases from bottom to top The heaviest Aloe vera dice, measuring 8x8x8, weighs 3.25 grams, illustrating this trend of diminishing weight as one moves upward.
With 50 kg Aloe Vera we have:
Figure 5.13 : Size of Aloe vera dice per a leaf
1st 2nd 3rd 4th 5th 6th 7th 8th 9th
THE STRENGTHS OF THE PROJECT
Aloe peeling and cutting system is designed and developed with many strengths
The Aloe vera peeling and cutting system boasts high versatility, enabling the production of various products such as Aloe vera yogurt and drinks, while ensuring food safety and ease of preservation and transport Cost-effective, this system is priced up to 75% lower than comparable products on the market It features observation hinges on the casing for monitoring the peeling process and an impressive capacity of 5000 kg/hr, facilitated by three peeling mechanisms Each mechanism operates independently with its own motor, allowing for flexible adjustments based on material volume Additionally, the system's simple mechanisms make assembly, maintenance, and repair straightforward.
THE WEAKNESSES OF THE PROJECT
Despite its strengths, the system has some minor weaknesses The project is developed and produced quickly, which can lead to occasional discrepancies in product performance Additionally, the high operational speed can result in noticeable noise during functioning.
CONCLUSION AND FURTHER RESEARCH
CONCLUSION
The innovative Aloe vera peeling and dicing system addresses key challenges such as high costs, time consumption, and food safety by eliminating manual labor in the processing of Aloe This advancement ensures improved food safety by minimizing the use of chemical compounds in the mixing gel Experimental results demonstrate that the new peeling and dicing mechanisms are both efficient and effective, with a working speed suitable for practical online applications Future research may explore the integration of this system with preceding and subsequent processes to enhance overall efficiency.
FURRTHER RESEARCH
The Aloe Vera peeling and cutting system, while complete, requires further enhancements to maximize production efficiency Key improvements include the implementation of automatic loading through image analysis, which can assess the orientation of Aloe Vera leaves, correct their direction, and eliminate damaged leaves Currently, after cutting, two or three employees manually place the tops and bottoms of the leaves onto conveyor lines By automating this process, we can significantly boost efficiency and ensure stable system operation.
To enhance mass production, it is essential to refine the dicing mechanism, focusing on cost reduction while maintaining high efficiency Due to the constraints of a graduation project, the system is designed for a single production build.
SUGGESTION
The project “Designing the Aloe vera peeling system applying to international standard ” is a highly practical one The effect of reducing workers in the initial
93 process is so positive that prosperously, this topic will be carried out a large amount of products to sell in market
With the inevitable limitations of the objective and subjective reasons of a thesis, the sincere feedbacks from teachers will be valuable lessons for us in future work
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