Conveyor Selection

Conveyor selection

Dr. Eng. M. A. Soliman

Introduction: A conveyor moves material between locations. Conveyors are generally powered by electric motors, hydraulic motors, or by gravity. Conveyors are classified according to their function or material conveyed.: Type of material conveyed.( Ex: Bulk materials, bottles, boxes, sacks, etc...) Type of conveying machine. (Ex: Rollers, belt, chains, slats, bucket, overhead, aprons, screws, oscillating, flight, pneumatic, and load-towing push-bar conveyors,) Example of roller conveyor:

Example of belt conveyor:

Conveyor Selection: When selecting a conveyor the following factors must be carefully defined: Type of material transported: Is it bulk material, or unit goods. Physical characteristics of transported goods. (ex for bulk materials: Lumpiness, repose angle, moisture content, abrasiveness, coefficient of internal friction, etc...) Dimensions of unit goods. Flow rate: tons per hour or number of units per hour. Load carrying capacity of structure. Distance traveled (Conveyor length). Direction of travel. (head to tail or tail to head)

Conveyor height from floor. Level change. ( Horizontal, upward or downward path.) Support type ( Floor stand, ceiling suspended, wall mounted, etc..) Environment and operating conditions ( food grade, moisture, water splash, dust, explosion hazards etc..) . Conveyors are usually classified according to their type (ex: roller, belt, slat, etc..), or sometimes according to the material being transported ( ex: bulk). Conveyors come in many forms and designs, the most common of which are listed in the table below. Type Roller Gravity Conveyors

Powered Roller Conveyors

Slider Bed Belt Conveyors Roller Bed Conveyors Chain Conveyors

Slat Conveyors

Overhead Conveyors, Manual.

Overhead Conveyors, Driven. Trough Conveyors.

Characteristics Horizontal or slightly inclined rollers carry unit loads. Low cost, low maintenance. Hand driven or gravity operated. Same as above except rollers are motor driven. Drive is by sprockets and chains, tangential belts , or round belt. Belt is supported on a slider bed. Low cost Belt is supported by rollers. Loads are carried on chain strands, running on a wear resistant polymer. Used with relatively heavy loads and pallets. ( 1-2 tons /unit) Plastic or Stainless steel slats running on wear resistant polymer. Continuous transportation of unit loads along a closed path. The carts carrying the loads are pushed or pulled by hand. Same as above, but could also change levels . Could also be used for bulk loads. Arrays of 2 or more rollers, elevate the sides of a rubber or polymer belt to confine bulk materials to the center of the belt. Could reach lengths of several kilometers. Can change

Application Transportation of unit loads, boxes, barrels, drums, cartons , occasionally sacks. Same as above. Some types could be used in applications requiring accumulation. Lightweight unit goods or bulk material loads . Medium to heavy loads, Assembly lines, pallet, unit loads transport.

Handling of bottles, or small similar items. Paint shops, assembly lines, garments industry, meat industry, assembly lines.

Same as above.

Bulk materials handling.

Load Carrying Car Conveyors, load Towing, and Walking Beam Conveyors Bucket Conveyors

Shelf, and Cradle Conveyors

Screw Conveyors

Oscillating Conveyors

Hydraulic and Pneumatic Conveyors

direction and level. Loads are carried on carts or special jigs, resting on guides, and towed by chains either overhead or running in trenches in the floor. Transportation on vertical or highly inclined paths Vertical transportation of unit goods on shelves. Could be used across several floors, allowing intermediate loading and unloading. Can be horizontal or inclined, used for short distances up to 40 m. Suitable for dusty, or hot materials.

Assembly lines, Heavy items, automotive industry, warehouses.

Elevating bulk , cement, flour, chemicals, sand, grain, peat, etc.. Elevating or lowering unit loads ,such as bags, bales, boxes, machine parts, etc....

Transportation of pulverized, granular, or small sized lumpy materials. Not suitable for sticky slumping or abrasive materials. Transportation of hot, toxic Transportation of bulk or dusty materials. Not loads, occasionally for unit usable with sticky loads. materials, or fine pulverized loads. Fluids or air carry the Bulk loads material in pipes. High throughput capacity.

Belt Conveyor Parts. A typical belt conveyor consists of a body with a bed to support the belt, a head ( drive) pulley, and a tail ( driven) pulley.

The drive pulley is usually larger than the tail pulley to give a larger contact area

between the belt and the pulley , therefore more traction The drive pulley is driven by a reducer (Gear motor) either directly mounted on the shaft of the pulley or through sprockets and chains.

Snub Idlers: Adjustable snub rollers in the section running towards the tail roller are particularly well suited for tracking and guiding a conveyor belt. To adjust the snub roller, shift it in the direction A-B. To achieve a good tracking effect, the arc of contact at the snub roller has to be minimum 30 degrees. The tracking effect can be further enhanced by a coated snub roller (friction cover made of rubber or plastic.

Crowning: The driving pulley is usually designed with a cylindrical-conical profile. Since the conveyor belt tends to run towards the highest point of a pulley (placed at a right angle to the running direction of the belt), the conical sides constantly center the belt towards the middle of the pulley. The cylindrical-conical driving pulley has a self-tracking effect on the belt. i.e. even with changing out-of-center running tendencies, the belt will be tracking optimally.

Take Up of Belts:

The required contact pressure of the conveyor belt to the driving pulley is achieved by means of a tensioning device The tension roller is usually tensioned by a spindle system that can be moved parallel to the running axis of the belt

Tensioning with the tail roller is the simplest solution.

If the center distance cannot be changed (e.g. with inserted conveying installations), the tensioning station is placed in the return side.

For long, heavily loaded installations requiring long take-ups, the tensioning station may be placed horizontally

Roller Bed Conveyors: When heavy total loads must be moved, it is best to use a conveyor bed with rollers instead of slider beds.

Heavy total loads can be moved without using large motors when a roller bed belt

conveyor is used. The roller pitch under load depends on the transported item size and weight. This depends on the load bearing capacity of the rollers. Belt materials with a higher coefficient of friction in the underside can be used for better traction, while wear is minimized because of the rolling surface.

Physical proprties Material A Agricultural lime Alum lumps powder Aluminum oxide hydrate sulphate Ammonia sulphate granulated Ammonium sulphate dry moist Ammonium chloride Asbestos loose pressed Ashes dry from coal moist from coal Asphalt for road metal solid B Bakelite powder Barley dry Baryta coarsegrained fine-grained Bauxite from quarry fine-grained, dry Beet unwashed washed mass, wet

Bulk Density

Max Angle of Inclination

Repose Angle

1,1-1,2 0,8-0,96 0,72-0,8 0,8-1,0 0,3 0,86 0,7-0,9

20 17 23

30 27 30-45

0,72-1,28

20

32

1,3 0,72-0,83

33 12

45

0,3-0,4 0,6-0,8 0,5-0,7

30

45

25

35-40

0,7-0,9 1,3-1,4

30 30

50

0,45-0,65 0,6-0,7 2,4-2,9

33 15

45 25-40

1,9-2,3 1,3-1,44

18 17

30 31

1,04-1,12 0,65-0,77 0,5-0,6 0,4-0,7

18 12-15 10-12 18-20

35 35-40 30-45 31

25 17 10

1,6

slices Bone meal Briquette lignite anthracite Broken stone, flint or granite

0,9-0,96 0,7-0,85 0,8-1,0 1,3-1,6

C Cement portland 1,2-1,36 aerated 0,8-1,2 clinker 1,2-1,5 slurry 1,4-1,7 Chile saltpetre 1,0-1,3 Clay dry dry in 1,6-1,9 1,0-1,2 1,52lumps, 75 mm 1,6 moist, 50 mm Coal anthracite, 0,8-0,96 0,7-0,9 coarse bituminous, 0,72-0,88 0,7-0,8 coarse lignite fine crushed Cocoa beans 0,53-0,6 Coffee beans, dried 0,35-0,42 0,51 beans, fresh Coke and furnace 0,4-0,55 coke Concrete light0,3-1,5 1,6-2,4 2,1weight concrete wet 2,4 dry Copra lumps 0,32-0,35 Corn 0,75 D Dolomite stone 1,2-1,6 E Earth filling, moist 1,5-1,8 1,15-1,20 with clay filling, dry F Feldspar 1,2-1,7 Fish 0,8-1,0 Fishmeal 0,55-0,65 Flour from grain 0,55-0,65 Fluor-spar coarse 1,7-1,9 1,4-1,7 fine-grained Foundry sand 1,3-1,45 1,45-1,6 prepared knocked 1,04 out core sand

20 20 18 10 18

35

20 6 18 12 25 20-22 18-20 18

39

35 35 15-24

16 18 22 22

27 38 38

15 20 10-15

28 35 25

20

45

25

20-30

9 10

20 30

22

40

22 20

45 35

23

40

20 21 30 25

45

24 22 26

32 39 41

40

33

Fullers earth, dry oily G Glass crushed broken Granite broken stones pebble, 10 mm Graphite crushed flakes Gravel dry moist Gypsum powder crushed, 3-10 mm

0,5-0,6 0,96-1^04

15 20

23

1,3-1,6 1,1

20 15

35 20-30

1,4-1,8 1,28-1,44

20 20

35 40

1,4 0,65

5

1,44-1,76 1,84-2,1 0,95-1,4 1,12-1,28

16 20 20 21

I Ice crushed 0,6-0,7 5 K Kaolin lumps 1,0 0,7-0,9 20 23 powder L Lead ore, fine 3,2-4,3 1,6 1,0-2,4 15 33 20 sulphate oxide Lime lumps burnt, 2 1,2-1,28 1,0 0,96 18 22 15 mm burnt, 2-20 mm Limestone from 1,35-1,45 18 quarry M Marble crushed 1,3-1,6 10-15 Marl 1,3-1,5 20 Millet, dry 0,6-0,7 15 Moler crushed, dry 0,6-0,7 Mortar, wet 2,4 20-22 O Oats, dry 0,4-0,6 12 Ore lead iron 3,2-4,3 1.6-3,2 1,6- 15 18-20 20 20 25 22 copper manganese 2,5 2-2,3 2,4-2,6 molybdenum zinc, crushed P Peanuts with shells 0,25-0,3 0,55-0,7 88 without shells Peas, dried 0,7-0,8 8 Phosphate fractional 1,2-1,4 0,96 12-15 13 pulverized Potassium from 1,2-1,35 12-15

35 32 40 40

30 35 45

30 45 40-45 5 30-45

20-30 35 25

35-40 30 35 39 38

20-30 30 25-30 26

quarry Potatoes Q Quartz coarsegrained, 30-75 mm pulverized, 1-2 mm

R Rice grain Rye, dry S Salt refined, fine refined, coarse Saltpetre Sand fine, dry fine, moist Sandstone, crushed Saw, dust Slag coarse, blast furnace crushed, dry crushed, wet Slate, crushed Soya bean whole broken cakes, 10 mm Stone shingle pebble gravel crushed, 100/250 mm pebble Sugar refined unrefined Sulphur lumps powder Super phosphate, granulated powder W Wheat, dry Wood-chips

0,7-0,8

12-15

1,35-1,52 1,3-1,45

18 20

35 35

0,7-0,8 0,67-0,73

8 8

20 23

1,1-1,3 0.65-0,9 1,1 1,45-1,75 1.75-2,1

11 18 16-18 20-22

25 30 30-45 30-40 45

1.36-1,44 0,15-0,21 1,28-1,44 0,96-1,04 1,44-1,6

18 22 16 16 20-22

40 36 30 30 45

1,3-1,5 0,7-0,8 0,48-0,64 0,65-0,7

18 12-16 15-18 17

21-28 35 32

1,4-1.5 1,5 1,4-1,6 1,8

20 20-25 20 15

35 35 38

0,8-0,96 0,88-1,04

10-15 23

30

1,2-1,4 0,8-1,0

18 21

0,8-0.9

15-17 18-20

33 30

0,5-0,7 0,2-0,5

12 22-24

40 30

Ergonomics Data

Conveyor Minimum:850 mm. Height: Standing Recommended:1050 Operator mm.

Conveyor Minimum:750 mm. Height: Sitting Recommended:850 Operator mm.

Distance Minimum:600 mm. Between Operator Recommended:900 and Wall mm.

Minimum:600 mm. Distance Between Recommended:1000 Operators mm.

Belting Material A belt has two components - carcass and covers. CARCASS The function of the carcass is to transmit and absorb the forces acting on the belt.

The carcass consists of one-or more plies of textile fabric with rubber on each side to give adhesion and flexibility. The longitudinal direction is called warp and the cross direction is called weft. One letter is designating each. Cotton (B) A natural fiber used in both warp and weft. Cotton is still used in conveyor belt fabrics, but it is being displaced by synthetic materials. Polyester (E) Synthetic fibers such as Terylene, Trevira, Diolen, and Tetoron. Polyester fabrics are not influenced by moisture or micro-organisms. They are very flexible, have stability in length, and are acid resistant. Polyamide (P) Synthetic fibers known as Nylon and Perlon. This fabric has more or less the same characteristics as Polyester, but not the length stability. Polyester-Polyamide (EP) The EP fabrics have Polyester as the warp and Polyamide as the weft. This combination gives the best possible fabric characteristics with the following advantages: - high strength in proportion to weight - high resistance to impact - negligable elongation - great flexibility, excellent troughability - not susceptible to humidity and micro-organisms COVERS The covers protect the carcass and give the necessary friction between belt and driving pulley and between belt and material.

First number:protection

Second number:protection

Third number : Mechanical

against solid objects IP-XXX against liquids IP-XXX IP Tests Definition IP Tests Definition

0

No protection 0

1

Protected against solid objects of over 50 mm 1 (e.g.accidenta hand contact)

2

Protected against solid objects of over 12 mm (e.g.fingert)

2

3

Protected against solid objects of over 2.5 mm (e.g.tools, wire)

3

4

Protected against solid objects of over 1 mm (e.g.thin wire)

5

Protected against dust (no deposits of harmful material)

6

Totally Protected against dust Does not involve rotaing machines

4

protection IP-XXX IP Tests Definition No No protection 0 protection Impact energy : Protected 0.22J against vertically 1 W= 0.150 dripping water Kg. (condensation) h= 0.15 m. Impact Protected energy : against water 0.375J dripping up to 2 15 degrees W=0.250 from the Kg vertical h= 0.15 m Impact Protected energy : 0.500J against rain at up to 60 3 W= 0.250 degrees from Kg the vertical h= 0.2 m. Protected against water splashes from all directions

5

Protected against jets of water from all directions

6

Protected against jets of water comparble to heavy seas

Impact energy : 2 J

5

W= 0.5 Kg from h= 0.2 m.

7

8

Protected against the effects of immersion to depths of between 0.15 and 1 m Protected against the effects of prolonged immersion at depth

7

Impact energy : 6 J W=1.5 Kg from h= 0.4 m

9

Impact energy : 20 J W= 5 Kg from h= 0.4 m.