1 Dr. C. L. Jones Biosystems and Ag. Engineeri Topics in Processing Materials Handling
1 Dr. C. L. Jones Biosystems and Ag. Engineering Topics in Processing Materials Handling.
Dec 24, 2015
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1
Dr. C. L. JonesBiosystems and Ag. Engineering
Topics in Processing
Materials Handling
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Assignment: – Read Chapter 8 handout
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• More on Screw-type Conveyors
• http://www.flexicon.com/us/Products/FlexibleScrewConveyors/index.asp
• http://www.mcs.drexel.edu/~crorres/Archimedes/Screw/Applications.html
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• More on Screw-type Conveyors
• Example: determining capacity and HP– Screw-type conveyor, 14 in. screw dia.,
conveying soy beans, 300 rpm, 25 ft. length
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling• Bucket Conveyors
– http://www.goughecon.com/
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• More on Bucket Conveyors
• Example: determining capacity and HP– Bucket conveyor with buckets like Fig.
8.10(b)– Bucket is 10.5 in. long, curve radius = 7 in.– Spacing is 3x projected width– Lift is 125 ft., belt speed = 300 ft/min,
handling wheat
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling• Oscillating conveyors (fig. 8.11)• Trough imparts velocities in x and y directions• Used often for metering components in mixing• Rate of movement is easy to change and
remains constant over long periods of time.• Hard to calculate performance…usually
established by testing …vendor will provide data from their testing labs
• http://www.goldequipment.com/gold-mining-equipment-info.html#ANIMATED%20.GIF%20Files
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Pneumatic conveyors (Fig. 8.13)• Moves granular material through a duct using
high-velocity stream of air.• Advantages:
– Low initial cost– Mechanical simplicity…1 moving part (fan)– Conveying path can be random and branched– Path can be changed easily– Can handle wide variety of materials– Self cleaning
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Pneumatic conveyors (Fig. 8.13)• Disadvantages
– High power requirement– Possible damage to conveyed materials
• 4 types of systems (fig. 8.14)– Suction: operates below atm. pressure– Low pressure: high vel. low density air (centrif. fan
<14in. water pressure)– High pressure: low vel. high density air (pos.
displacement blower)
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Pneumatic conveyors (Fig. 8.13)– Fluidized system: high press. air and high
density air (material in air like an air-material slurry) Low conveying velocities
• Suction system best for – unloading matls. where point of unloading
may move (trucks, freight cars, boats)– Matls. with texture that would not pass
easily through valves, screw conveyors…
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Pneumatic conveyors (Fig. 8.13)• Pressure system best
– Where point of discharge varies– Loading trucks, freight cars, barges
• Vertical movement (lift) usually 50 ft/sec. granular lift rate– So air rate=50 ft/sec + rate to support material– Usually 15 – 50 ft^3/lb of material– Table 8.5
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Pneumatic conveyors (Fig. 8.13)
• Static air pressure =– wall-air friction loss + – pressure from weight of matl. +– energy loss from matl. rubbing pipe
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling• Pneumatic conveyors (Fig. 8.13)• Horizontal movement• Losses from friction of air on walls, grain on
air, grain on walls, and grain on grain• Disagreement on whether air rates are lower
or higher than vertical movement!!!• http://www.vigan.com/code/EN/gene.asp
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Gravity Conveyors
• Simple
• Series of rollers or wheels
• Level or very slight incline
• Handles boxes generally
• Moves by gravity or by hand if level
• Good for intermittent service
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling
• Cranes/Hoists
• Used in construction, generally
• Unloading barges
• Machine and assembly shops to move parts and units
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Dr. C. L. JonesBiosystems and Ag. Engineering
Materials Handling• Trucks and Carts• Widely used in manufacturing and
warehouses• Forklifts• Dollies• Can fill in where a permanent conveyor
system isn’t practical• Intermittent flow rate processes
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