JOURNAL OF ADVANCEMENT IN ENGINEERING AND TECHNOLOGY

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1 JOURNAL OF ADANCEENT IN ENGINEERING AND TECHNOLOGY Journal hoepage: Research Article Open Access Design of a aterial Handling Equipent: Belt Conveyor Syste for Crushed Liestone Using 3 roll Idlers I. A. Daniyan *, A. O. Adeodu and O.. Dada Departent of echanical & echatronics Engineering, Afe Babalola University. *Corresponding author: I. A. Daniyan Departent of echanical & echatronics Engineering, Afe Babalola University, Ado Ekiti, Ekiti State, Nigeria. E-ail: afolabiilesani@yahoo.co Received: January 6, 2014, Accepted: January 14, 2014, ublished: January 16, ABSTRACT In the process or anufacturing industry, raw aterials and products need to be transported fro one anufacturing stage to another. aterial handling equipent are designed such that they facilitate easy, cheap, fast and safe loading and unloading with least huan interference. For instance, belt conveyor syste can be eployed for easy handling of aterials beyond huan capacity in ters of weight and height. This paper discusses the design calculations and considerations of belt conveyor syste for liestone using 3 rolls idlers, in ters of size, length, capacity and speed, roller diaeter, power and tension, idler spacing, type of drive unit, diaeter, location and arrangeent of pulley, angle and axis of rotation, control ode, intended application, product to be handled as well as its axiu loading capacity in order ensure fast, continuous and efficient oveent of crushed liestone while avoiding halt or fatalities during loading and unloading. The successful copletion of this research work has generated design data for industrial uses in the developent of an autoated belt conveyor syste which is fast, safe and efficient. Keyword: Belt Conveyor syste, Idler, Loading, aterial handling equipent, Unloading. INTRODUCTION Different ethods such as fork lifting, use of bucket elevators, conveyors systes, crane, etc. has been identified for lifting or transporting bulk aterials or products fro one place to another in the anufacturing industries depending on the speed of handling, height of transportation, nature, quantity, size and weight of aterials to be transported. However, occasional halt or fatalities encountered while loading and unloading in the industry are source of concern. The objective of this research work is to provide design data base for the developent of a reliable and efficient belt conveyor syste that will reduce cost and enhance productivity while siultaneously reducing dangers to workers operating the. Conveyor syste is a echanical syste used in oving aterials fro one place to another and finds application in ost processing and anufacturing industries such as: cheical, echanical, autootive, ineral, pharaceutical, electronics etc. It is easier, safer, faster, ore efficient and cheaper to transport aterials fro one processing stage to another with the aid of aterial handling equipent devoid of anual handling. Handling of aterials which is an iportant factor in anufacturing is an integral part of facilities design and the efficiency of aterial handling equipent add to the perforance level of a fir [1]. Conveyor systes are durable and reliable in aterials transportation and warehousing. Based on different principles of operation, there are different conveyor systes naely: gravity, belt, screw, bucket, vibrating, pneuatic/hydraulic [2], chain, spiral, grain conveyor systes etc. The choice however depends on the volue to be transported, speed of transportation, size and weight of aterials to be transported, height or distance of transportation, nature of aterial, ethod of production eployed. aterial handling equipent ranges fro those that are operated anually to sei-autoatic systes and to the ones with high degree of autoation. The degree of autoation however depends on handling requireents. aterial handling involves oveent of aterial in a anufacturing section. It includes loading, oving and unloading of aterials fro one stage of anufacturing process to another. A belt conveyor consists of an endless and flexible belt of high strength with two end pulleys (driver and driven) at fixed positions supported by rollers. In this work, 3 roll idlers are required for adequate support of aterials transported and protection of the belt along its length. ulleys are used for providing the drive to the belt through a drive unit gear box powered by an electric otor. It also helps in aintaining the proper tension to the belt. The drive iparts power to one or ore pulleys to ove the belt and its loads. aterials are transported over the required distance as a result of friction generated between the roller surface and the oving belt set in otion by a rotating J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN:

2 pulley (drive pulley). The other pulley (driven or idler pulley) acts as a wheel around which the aterial rotates and returns in a continuous process. Continuous processes are characterized by non-stop otion of bulk or unit loads along a path without halt for loading and unloading [3]. The peculiarities of a belt conveyor is that it is easy and cheap to aintain, it has high loading and unloading capacity and can transport dense aterials econoically and at very high efficiency over long distance allowing relative oveent of aterial [4]. Belt conveyor can also be used for diverse aterials: abrasive, wet, dry, sticky or dirty aterial. Only a single roller needs to be powered by driver pulley and the roller will constantly spin causing the aterials to be propelled by the driving roller. aterial handling equipent such as belt conveyors are designed to load and unload aterials fro one stage of processing to another in the fastest, soothest, ost judicious, safest, and ost econoical way with iniu spillage. Belt conveyors are eployed for conveying various bulk and unit loads along horizontal or slightly inclined paths and for transporting articles between various operations in production flow lines [3]. A belt conveyor can be horizontal, incline or decline or cobination of all. With the aid of pneuatic cylinder, the height of the conveyor is adjustable so as to load and unload at different height. Fig. 1: Belt Conveyor Design Considerations According to [1], the design of an effective and efficient aterial handling syste which will increase productivity and iniize cost, the guidelines norally followed are: 1. Designing the syste for continuous flow of aterial (idle tie should be zero); 2. Going in for standard equipent which ensures low investent and flexibility; 3. Incorporating gravity flow in aterial flow syste; and 4. Ensuring that the ratio of the dead weight to the payload of aterial handling equipent is iniu. The transportation route affects the overall cost of aterial handling. An efficient aterial handling equipent will reduce cost per volue of aterial transported and ensure that aterials are delivered to the production line safely. The design of belt conveyor syste involves deterination of the correct diension of the belt conveyor coponents and other critical paraeter values so as to ensure optiu efficiency during loading and unloading conditions. Soe of the coponents are: Conveyor belt, otor, pulley and idlers, rollers, pneuatic cylinder etc. The design of a belt conveyor syste takes into account the followings: i. Diension, capacity and speed ii. Roller diaeter iii. Belt power and tension iv. Idler spacing v. ulley diaeter vi. otor vii. Type of drive unit viii. Location and arrangeent of pulley ix. Control ode x. Intended application xi. axiu loading capacity Belt Diension, Capacity and Speed The diaeter of the driver and driven pulley is deterined by the type and diension of conveyor belting. The diaeter of the pulley ust be designed such that it does not place undue stress on the belt. The length of a belt conveyor in etres is the length fro the centre of pulley parallel to belt line. Belt length is dependent on both the pulley diaeters and centre distances [4]. v d Π (1) Belt speed; d diaeters of rollers; and Π pi Capacity is the product of speed and belt cross sectional area Generally, belt capacity (kg/sec) is given as: BC. 3.6 A ρ (2) A belt sectional area ( 2 ); ρ aterial density (kg/ 3 ); and belt speed (/s) The ass of aterial (live load) per etre (kg/) loaded on a belt conveyor is given as: C 3.6 C Conveyor capacity (355 tonnes/hr); and belt speed (1.25 /s) kg. (3) J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN:

3 The agnitude of belt speed (/s) can be deterined fro equations 1, 2, 3 or 6 and can as well be gotten fro the catalogue for standard belt. Belt speed v (/s) depends on loading, discharge and transfer arrangeent, aintenance standards, lup size [5]. The deterination of belt width is largely a function of the quantity of conveyed aterial which is indicated by the design of the conveying belt [6]. The value of belt capacity fro equation 2 deterines the value of lup size factor. Another iportant factor in deterining the belt capacity is the troughing angle. Belts are troughed to allow the conveyor load and transport aterials. As trough angle increases, ore aterials can be transported. For standard 3 idler rollers of equal length the ost coon trough angle is 350. The belt width ust be wide enough to deal with the aterial lup size. Angle of surcharge is one of the ost iportant characteristics in deterining the carrying capacity as it directly governs the cross sectional area of aterial in the belt and hence the volue being conveyed [5]. The surcharge angle depends on friction between the belt and the aterial and how the aterial is loaded. The steeper the conveyor, greater the belt capacity and the lesser the surcharge angle. Since the liestone to be handled is abrasive, heavy, with specific gravity between tonnes/3 and lup size up to 75, a belt of iniu width of 1200 and speed of 1.25 /s is preferred according to design values [7]. For 3 equal roll idlers with surcharge angle of 250 and troughing angle of 350 the capacity factor is 1.08 [5]. The capacity in tonnes/hr of a conveyor consisting of 3 equal roll idler is given as CT ρ Cf C (4) CCapacity in tonnes/hr of a belt conveyor consisting of 3 equal roll idler; C T Capacity of troughed belts for 3 roll equal length idler (175); ρ aterial density in kg/ 3 (1500); C f Capacity factor (1.08); and Belt speed in /s (1.25) Fro equation 2.4, the overall capacity of the belt conveyor consisting of 3 equal roll idler is 355 tonnes/hr. For belts running horizontally and loaded evenly, the voluetric belt load also is given as: L L C W (5) L oluetric belt load ( 3 /hr); L C Load capacity of the belt conveyor (tonnes/hr); and WSpecific Weight of the conveyed aterial (tonnes/ 3 ) As belt tend to wander a bit in operation, the overall face width of the pulley should exceed the belt width by 150 [6], if serious edge daage is to be avoided. For haulage efficiency, conveyors should be operated fully loaded at the axiu recoended speed and capacity. Roller diaeter The roller support belt and facilitates easy as well as free rotation of the belt conveyor in all direction. The correct choice of roller diaeter ust take into consideration the belt width [7]. The relationship between the axiu belt speed, roller diaeter and the relative revolution per inute is given as: 60 n (6) D Π n no of revolution per inute; D roller diaeter (); and belt speed (/s) The belt width is designed as 1200, the belt speed is 1.25 /s, the roller diaeter is therefore designed as 108 [7]. Fro equation 6, the no of revolution per inute n 220 rp. The conveyor length horizontaldis tan ce inclinationangleθ The inclination angle is 10 0, the conveyor length is 100, and the conveyor height is 10. Belt basic length 2 length along conveying route (8) (7) Fro equation 8, basic belt length The roll diaeter for belt is given as 2 D d ( L G + (9) D Overall diaeter (); D core diaeter (); L Belt length (); and G Belt Thickness () The length of a belt on roll is given as: D d L ( d + ( ) π N (10) 2 Or L H N π (11) DOutside diaeter of the roll (); ddiaeter of the roll centre (); N no of wraps of the belt H Height of the centre core (); and π J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN:

4 Belt ower and Tensions The longer the length of the belt, the ore the power required for the conveyor and the higher the vertical distance of the lift, the higher the agnitude of power required. The power (kw) at drive pulley dru is FU (12) F U : Total tangential force at the periphery of the drive pulley (N); : Belt speed (1.25 /sec); and F p U (13) ower required for the conveyor to produce lift can also be calculated as: C L 3.75 (14) power required for conveyor (kw); C conveyor capacity (355 tonnes/hr) (98.6 kg/sec); and LLift (10 ) 3.7 kw. The belt of the conveyor always experience tensile load due to the rotation of the electric drive, weight of the conveyed aterials and due to the idlers. The belt tension ust be great enough to prevent slippage between the drive pulley and the belt [8]. Belt tension at steady state is given as: T 1.37 f L g[2 + (2 + )cos( θ )] + ( H g ) SS i b T ss Belt tension at steady state (N); f Coefficient of friction (0.02) LConveyor length (100 ); (15) (Conveyor belt is approxiately half of the total belt length) gacceleration due to gravity (9.81 /sec 2 ); i Load due to the idlers (570 kg); b Load due to belt (577.5 kg); Load due to conveyed aterials (78.88 kg); θ Inclination angle of the conveyor (10 0 ); and Hertical height of the conveyor (10 ). T ss 71 KN During the start of the conveyor syste, the tension in the belt will be uch higher than the steady state. The belt tension while starting is Ts Tss KS (16) T s Belt tension while starting (N); T SS Belt tension at the steady state (71KN); and K S Start up factor (1.08). T s KN For inclined belt, the drive at head pulley is: T T + T (17) ax e 2 while the drive at tail pulley is T T + T (18) ax e 2 J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN: OR T T + T +belt tension-return side friction (19) ax e 2 T e is effective tension (KN) Te total epty friction + load friction + load slope tension (20) Total epty friction F ( L+ t ) W 9.81e e (21) C 3 Load Friction Fe ( L+ tf) 9.81e (22) 3.6 Return side tension f F W L e 3 e (23) C H 3 Load slope tension 9.81e (24) 3.6 F e Equipent friction factor (0.0225); C Belt Conveyor capacity (355 tonnes/hr); Belt speed (1.25 /sec); t f Terinal friction constant (60 ); WWeight of aterial and belt in ( kg/); LLength of conveyor (100 ); and HHeight of conveyor (10 ) Fro equation 21, total epty friction is N. Fro equation 22, load friction is N. Fro equation 23, return side tension is 5.795N Fro equation 24, load slope friction is N 3

5 The effective tension T e according to equation 20 is KN. For horizontal and elevating conveyors, the terinal friction constant t f, expressed in etres of centre to centre distance up to 300 centre 60 And the equipent friction factor F e [5]. axiu tension (T ax ) is the belt tension at the point where the conveyor experiences the greatest stress. T ax can be found at different sections in the belt. Tax (1 + K) T (25) K Drive factor TTension at a particular point (KN) However, unitary axiu tension T Uax (N/) of the belt is defined as: Tax 10 T (26) U ax b T ax Tension at the highest stress point of the belt or steady state tension in a conveyor (71 KN); and b Belt width (1200 ). T Uax 0.59 KN. The belt power (kw) is given as T (27) b e T e effective tension (1.141 KN) Belt speed (1.25/sec) b 1.43 kw Belt tension of a conveyor syste is of a varying value along the syste flight and is governed by the following influencing factors: length and track of the syste, nuber and arrangeent of pulley, characteristics of the driving and braking equipent, type and location of the belt take up devices and operating and loading state of the syste [9]. Idler Spacing Idlers are installed at graduated spacing to ensure that the sag as a result of load varies inversely with the tension in the belt. Live load is calculated as kg fro equation 3.3 Total live load (kg) TL LL LC (28) LC is conveyor length (100 ) TL 7.88 KN Dead load is the load consisting of weight of roller, belt and drive pulley. The idler spacing at any point can be obtained fro: 8 T Sg IS 3 ρ 9.81e (29) ρ ass of belt and live load ( kg/); T Tension at a particular point (KN); and S g ercentage of the idler spacing (0.01) An idler spacing of 1.0 is recoended for a belt conveyor syste conveying a aterial of 1500kg/ 3 and on a belt width of 1200 [6]. ulley Diaeter ulleys are anufactured in a wide range of sizes. The selection of pulley takes into account the wrap angle (1800), belt speed (1.5 /sec), ethod of belt strain, belt tension T, belt width (1200 ) and type of splice of the conveyor belt. The pulley diaeter is obtained fro standard value fro the catalogue. Once the pulley diaeter is deterined, the size of the coupling can also be decided fro the catalogue. ulley wraps length at terinals 2 Π D (30) Diaeter of pulley (800 ) [6]. ulley wraps length at terinals 5. Drive pulley can be lagged to increase friction and iprove transission between belt and pulley [10]. Elastic lagging helps to keep pulley clean so as to increase duration of friction while grooved lagging helps in reoval of oisture so as to iprove friction. The effective pull F U (N) is given as B B FU µ T g ( + ) + µ R g( + i) (31) 2 2 µ T : Coefficient of friction with support rollers (0.033) µ R : Coefficient of friction with skid plate (0.33) g : Acceleration due to gravity (9.8/s 2 ) : Total load of conveyed aterials (78.88 kg) B : ass of belt (577.7 kg) i : ass of roll idlers (570 kg) F U 2.9 KN Recall fro equation 9, the power (kw) at drive pulley dru is FU Recall equ (12) F U : Total tangential force at the periphery of the drive pulley (2.9 KN); : Belt speed (1.25 /sec); and Fro equation 3.9, 3.62 kw. The acceleration of the conveyor belt is given as: TS TSS A [ L ( )] i b J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN: (32) T s Belt tension while starting (76.68 N); T SS Belt tension at the steady state (71 N); LConveyor length (100 ); i Load due to the idlers (570 kg/); b Load due to belt (577.5 kg/); Load due to conveyed aterials (78.8 kg/); The acceleration A (/sec 2 ) of the conveyor belt is 2.39e -5 /sec 2. Belt breaking strength B bs (N) paraeter decides the selection of the conveyor belt. Belt breaking strength can be calculated as: Cr p Bbs (33) C

6 C r Friction factor (15); C v Breaking strength loss factor (0.75); power at drive pulley (3.63 kw); and Belt speed (1.25/sec) The breaking strength is otor The iniu otor power for sizing of the otor is in p (34) η in iniu otor power (kw); p ower at drive pulley (3.62 kw); and η : Efficiency of the reduction gear (0.9) kw. The next standard otor greater than in will be sufficient [11], [12]. A standard otor of 5.0 kw is chosen. Alternatively, To deterine the otor horse power hp in Where H req η hp : in (35) H H + H + H (36) req e j H e Horse power required to drive the conveyor epty H Horse power required to ove aterial horizontally H j Horse power required to elevate aterial. Torsional oent is given as 1 ( + µ ) (37) t 2 D F Wg D Diaeter of pulley (); F Force (N); µ Coefficient of friction; WWeight of aterial and Belt (kg/); and gacceleration due to gravity (/s 2 ) The nuber of revolution per inute (n) of the otor is given as 9550 n (38) t ower (kw); and t Torsional oent (N/) The cycle tie of conveyor is given as: 2L Ct (39) LLength of conveyor (100 ); and Belt speed (1.25/sec) The cycle tie of the conveyor is 160 s -1 Torque (KN) is calculated as: T 9.55 ulleyrp (40) power required for the conveyor (3.7 kw) ulley rp 26.2 T1.35KN Shaft Design Shaft design consists priarily of deterination of the correct shaft diaeter that will ensure satisfactory rigidity and strength when the shaft is transitting otion under different operating and loading conditions. The values of belt width and pulley diaeter helps in selecting the size of shaft diaeter fro different conveyors hand book. Control Copact rograable Controllers otherwise known as application controllers can be used for the control of the syste. These controllers can e used for tie control and supervisory functions such as: conveyor speed control, speed control of individual drives, speed and belt slip control, load equilibration between two driving dru and speed difference control between two otors on one driving dru [13]. RESULTS The followings are designed values were obtained for belt conveyor syste for liestone using 3 roll idlers. Table 1: Design alues for Belt Conveyor Syste S/N araeter alues 1. Belt width () Length of Conveyor () Basic belt length () Belt speed (/sec) Height of Conveyor () Angle of 10 inclination(degree) 7. Troughing angle (degree) Surcharge angle Conveyor capacity 355 (tonnes/hr) 10. Equipent friction factor Terinal friction factor 60 () 12. Belt tension while starting (KN) 13. Belt tension at steady state 71 (KN) 14. Load due to idlers (kg/) Load due to belt (kg/) Load due to aterials conveyed (kg/) 17. ower at drive pulley (kw) Acceleration of conveyor 2.39e -5 belt (/sec 2 ) 19. Efficiency of reduction 0.9 gear (drive efficiency) 20. iniu otor power 4.0 (kw) J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN:

7 21. Total tangential force (KN) Idler spacing () Unitary axiu tension 0.59 (KN) 24. Effective pull (KN) Diaeter of pulley () ulley wraps length at 5 terinals () 27. Total epty friction (KN) Load friction (KN) Return side friction (KN) Weight of aterial and belt (kg/) 31. Total live load (KN) Belt power (kw) ower required by 3.7 conveyor (kw) 34. aterial density (kg/ 3 ) aterial lup size () Cycle tie of conveyor 160 (s -1 ) 37. Friction factor Breaking strength loss 0.75 factor 39. Wrap angle (degree) Belt thickness () Torque (KN) Capacity factor Breaking strength Liitation of Study The construction of a belt conveyor syste requires high capital base. This is a ajor constraint that liits this work to design only and as such perforance evaluation cannot be carried out on the belt conveyor syste. However, the research work provides design data for developent of belt conveyor syste for industrial uses. CONCLUSION Using the designed values above, a belt conveyor syste with 3 roll idlers can be developed for conveying crushed liestone efficiently without belt spillage and fatalities. A N 450 double weave standard rubber belt with the specifications above will sufficiently convey the crushed liestone. The belt conveyor syste is designed with high degree of autoation, loading, oveent and unloading efficiency. It is also very flexible, safe, with low initial, operational and aintenance cost while eliinating repetitive short distance oveent in the anufacturing industry. REFERENCES 1. Ogedengbe, T. I. (2010). Lecture Note on Applied Techniques of roduction anageent. pp Richardson, J. F., Harker, J. H. and Backhurst, J. R. (2002). article Technology and Separation rocess. ol., 2, 5th Edition, Elsevier publisher, New Delhi, India. p anaane, S. S., ane,. A. and Inader, K. H. (2011). Design and its erification of Belt Conveyor Syste Used for ould Using Belt Cop Software. Int. Journal of Applied Research in echanical Engineering. ol. 1(1) pp Taiwo, A., Jekayinka, S. O. and Onawui S. A. (2005). echanical aintenance and Repairs. Orsoe entures Ltd, Ibadan. p Anath, K. N. and Rakesh,. (2013). Design and Selecting roper Conveyor Belt. Int. Journal of Advanced Technology. ol. 4(2) pp Fenner Dunlop Conveyor Handbook (2009). Conveyor Belting Australia. p Ruleca. Technical inforation. roject and Design Criteria for Belt conveyors. p Besser Service Bulletin. (2006). Conveyor Belt Basic Rules and rocedure for Tracking. pp hoenix Conveyor Belt Systes. (2004). Design Fundaentals. Haburg pp Sandvik (2000). Conveyor Coponents. p Orthan Conveying Syste (2004). Belt Conveyor Catalogue. pp Conveyor Equipent anufacturers Association (CEA). Belt Conveyors for Bulk aterials 6th Edition, pp ABB-rocess Industries (2000). ariable-speed drives for Belt Conveyor Systes. p J. of Advanceent in Engineering and Technology: oue1/issue1 ISSN: