Design and Fabrication of Palm Fronds Petioles Stripping Machine

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1 Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(4): Scholarlink Research Institute Journals, 2015 (ISSN: ) jeteas.scholarlinkresearch.com Journal of Emerging Trends Engineering and Applied Sciences (JETEAS) 6(4): (ISSN: ) Design and Fabrication of Palm Fronds Petioles Stripping Machine Ebunilo, P. O. B 1., Efosa, O., Osaghae, F. U 2. 1 Mechanical Engineering Department, University of Benin, Nigeria. 2 Ministry of Works and Transport, Edo State, Nigeria Corresponding Author: Efosa, O Abstract With the increasing population of Nigeria comes an increase also in the number of households, schools, hospitals, religious worship centers, commercial and industrial complexes, etc., all needing devices to remove waste and keep their immediate environment clean. Although, a variety of cleaning devices and equipment are available, Nigerians have shown increasing preference for the brooms made locally from palm frond petioles. Hence the demand for traditionally made brooms is huge and not readily met and therefore emphasizing the need to design a mechanized system for broom production. Thus, a machine for the stripping of palm frond petioles for local broom production in Nigeria was designed, fabricated and tested. The fabricated prototype consists mainly of a cylindrical drum, a vee holed spring loaded stripping knife, a flywheel, a geared electric motor and belts. The machine is loaded with four (4) petioles manually at a time during operation. The results showed that the machine can strip the petioles in 3 seconds as compared with 27 seconds when it is undertaken manually. With this machine, it is hoped that the demand for local brooms would be met, and the business of broom production would become more profitable to those involved. Keywords: petioles, broom, palm fronds, knife assembly, cleanliness INTRODUCTION The popular saying that Cleanliness is next to Godliness is a statement which man has consciously exemplified through acts of personal and environmental sanitation and hygiene. Such acts of environmental sanitation include the use of various kinds of devices to remove waste, or unwanted materials from our living space. Devices for environmental cleaning such as brooms, vacuum cleaners, mops, rakes, etc, have found widespread usage around the world with some being more prevalent in various regions. A typical example is the extensive usage of the broom locally made from palm fronds in Nigeria. Brooms can be made of synthetic materials like plastics or natural materials as obtained from palm fronds, especially from the Oil Palm tree (Elaesis guineensis) in Nigeria. How the broom made from natural materials has become so widely used in Nigeria can be deduced from its advantages over other cleaning devices and the ever increasing population of the country which is still developing. With a population of over one hundred and sixty million people in Nigeria many of whom dwell in homes at an average of 5.5 persons per home, (National Population Commission, 2006) a predicted million homes exist within the country which uses at least five or more brooms for cleaning. Furthermore, Nigeria is fast growing industrial nation with lots of schools, hotels, industries, public and private establishments etc., where people dwell and they all have brooms for cleaning. The advantages of the broom made from natural materials over other cleaning devices in Nigeria are so numerous, crucial amongst which are its nonenvironmental pollution as against the synthetic types like rubber which do not degrade easily, hence pose environmental hazard. Other advantages include its non-use of electrical or fuel power for operation, its ease of handling, storage, low cost and use. From the advantages and the population analysis above one may now begin to imagine the economic relevance of the natural broom device and the huge investment possible with its production, sale and distribution. Hence, it is the objective of this research to design and fabricate a machine for mechanical stripping palm frond petioles with the result of increasing local broom production. MATERIALS AND METHODS Elements of the Design The machine consists mainly of the following components which include The Frame: this is the structure on which other components are mounted. The Drum: this is in two parts; a rotating part; and a stationary part. While the rotating part of the drum carries the spring loaded broom holder or gripper, the stationary part carries a cam which helps to release the spring loaded gripper. The Shaft: this is the horizontal member that passes through the center of the drum and it is mounted on the frame via two bearings. The Flywheel: this member enables the continued and timely engagement and disengagement of the 236

2 clutch for intermittent stopping for feeding the crowns and rotation of the drum. The Peeling or Stripping Knife: this is the sharp vee edged component that does the actual peeling of the leaves from the petioles. The Bearings: these are roller bearings of 10 mm internal diameter and 20 mm outer diameter necessary for the smooth rotation of the shaft. The Spring: this is attached to the gripper for efficient gripping during peeling, and for un-gripping during dislodging of the peeled crowns. Preliminary Measurements and Detailed Design Prior to the design, some preliminary measurements were conducted to determine average length and diameter of short, medium and long brooms to be 44.7 cm and 0.22 cm, 65.7 cm and cm, and 67.2 cm and 0.22 cm respectively. Determination of Stripping Time of a Palm Frond Petiole From experiment, the minimum force required to strip a broom is 20 N irrespective of the length or diameter. The time to strip various categories of brooms i.e short, medium, as determined experimentally, was found to be 3 seconds. Determination of Energy and Power Required for Stripping With a force of 20 N needed to strip the broom for 3 seconds, the energy and power required for stripping a broom of average length of 67 cm is computed thus: Energy, E = = 20 Where, E = energy = force = characteristic length of broom Thus, Power, P = = = 4.47 W Where, t = time Determination of Drum Centripetal Force. The centripetal force required to keep the drum rotating is computed thus: Where, = centripetal acceleration = mass of rotating drum = radius of drum = velocity of rotating drum. (1) Expressing in terms of the angular velocity of the drum about its axis of rotation yields Since OR (2) Where, = the period for one revolution of the drum. For a drum rotating at 30 rpm, and Thus, with a mass of 20kg, Shaft Design and Selection Shafts may be designed on the basis of strength, or rigidity and stiffness while considering the following: a. If the shaft is subjected to twisting moment or torque only b. If the shaft is subjected to bending moment only c. If the shaft is subjected to fluctuating loads d. If it is subjected to combined twisting and bending moments e. If it is subjected to axial loads in addition to combined torsion and bending loads. In view of the nature of this project, the shaft was designed for fluctuating loads since it is subjected to fluctuating bending moment as a result of the variable weight bearing from the grains movement and also fluctuating torque due to its rotation about its neutral axis. From first principle (Khurmi and Gupta, 2004), Where = Twisting moment or torque acting upon the shaft = torsional shear stress, and = Distance from neutral axis to the outermost fibre = Polar moment of inertia of about the axis of rotation Substituting for these parameters yields Consideration for subjecting shaft to bending moment only yields (Ryder, 1985), Where = bending moment = second moment of area of shaft cross section about its axis of rotation = bending stress, and = distance from neutral axis to the shaft outer fibre. Substituting yields. 237

3 As earlier stated, the shaft is subjected to both fluctuating torque and bending moment, and therefore the combined shock and fatigue factors are taken into account to compute the equivalent twisting moment ( ) and the equivalent bending moment ( ) which are respectively given by = Where = combined shock and fatigue factor for bending = combined shock and fatigue factor for torsion Determination of Coefficient of Fluctuation of the Flywheel The difference between the maximum speeds during a cycle is called maximum fluctuation speed of the flywheel. The ratio of the maximum fluctuation of speed to the mean speed is called coefficient of fluctuation of speed (Khurmi and Gupta, 2005). The coefficient of fluctuation of speed is a limiting factor in the design of flywheel. It is given by the expression: Where = coefficient of fluctuation of speed and = are the maximum and minimum angular speed. It varies depending upon the nature of service to which the flywheel is to be employed. Determination of Coefficient of Fluctuation of Energy This is defined as the ratio of the maximum fluctuation of energy to the work done per cycle. Usually denoted by, it is expressed mathematically as (Shigley and Mischke, 2001): = RESULTS AND DISCUSSION Tests and Results Fresh palm fronds were cut from the palm tree. The petioles were removed from the frond and stacked into a pile. The palm frond stripping machine was checked to ascertain that it was in good working condition. The petioles were thereafter loaded into the machine in batches of four petioles. Successive stripping of other batches of petioles was done and the result of the test was recorded as shown in Table 1 A stripping process was also carried out manually by two women who are very experienced in the art of stripping petioles. Table 1: Result of mechanized stripping Batches Time to strip Fully Partially Not TOTAL Table 2: Result of manual stripping Batches Time to strip Fully Partially Not TOTAL Table 3: Comparing mechanized and manual stripping process Performance Mechanized Manual stripping stripping Time to strip 40 petioles Fully Partially 3 0 Un- petioles 0 0 Average batch time 3 27 They were given 40 petioles to strip using sharp knife. The exercise was recorded as done for the machine petioles stripping. Tables 2 and 3 show the result for the manual stripping of petioles. DISCUSSION From the table of results, it is seen that the machine a total of 40 petioles in a total time of 30 seconds at an average time of 3 seconds per batch of 4 petioles. Amongst the 40 petioles, only 3 petioles were partially while 37 petioles were completely. The two women that conducted manual stripping took a total of 271 seconds to strip 40 petioles averaging a time of 27 seconds per batch of 4 petioles. All 40 petioles were cleanly and completely by the manual procedure. From the analysis of results, it is inferred that the mechanized stripping of broom petioles is faster and more productive than the manual process and thus holds better promise of industry. 238

4 CONCLUSION From the analysis carried out, it is obvious that the mechanized stripping of palm frond petioles is more effective, faster and productive in output per time and safer. It is evident that in the bulk production of brooms, commercial and very profitable quantities can be produced in lesser time using the mechanized process than the manual process while drastically reducing human occupational hazard inherent in broom making Figure 1: Pictorial View (Isometric) Parts List Item No. Item Description No. Off 10 Knife Assy 1 14 Knife Assy Frame 1 239

5 Figure 3: Rendered View Item No. Parts List Item Description 5 Stationary Drum 1 7 Rotating Drum 1 8 Electric Motor Pulley 1 9 Bearing Assy 2 10 Knife Assy 1 11 Stripper Assy 1 12 Clutch Assy 1 No. Off 240

6 Parts List Item No. Item Description No. Off 1 Frame 2 Electric Motor 1 3 Shaft Pulley 1 4 Drive Shaft 1 5 Stationary Drum 1 6 Vee - Belt 1 1 Figure 2: Orthographic Projection REFERENCES Dada M Potentials of Palm Tree to the Nigerian Economy. World Journal of Agricultural Sciences, IDOSI Publications, ISSN: ; Vol 8(3); pp Khurmi R. S., and Gupta J. K A Textbook of Machine Design. First Multicolour Edition, Chand Series, New Delhi, India Khurmi R. S., and Gupta J. K Theory of Machines. Eurasia Publishing House, New Delhi, India. National Population Commission Nigerian Population and Housing Census. Ryder G. H Strength of Materials. 3 rd Edition, MacMillan Publishers Ltd, London. Shigley J. E., and Mischke C. R., Mechanical Engineering Design, 6 th Edition, McGraw-Hill Companies Inc., New York 241