recibo de materias primas · design calculations for downspouts • example: determine the height...
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SOUTHERN AFRICA FEED MANUFACTURING TRAINING ACTIVITY
MATERIALS HANDLING
Carlos A. Campabadal International Grains Program (IGP)
Kansas State University
MARCH 9TH , 2012
MANHATTAN, KANSAS
PRESENTATION OUTLINE
• Materials Handling
– Important concepts for grain and feed ingredient receiving
– Types of materials handling equipment
• Bucket elevator
• Screw conveyor
• Pneumatic systems
2
GRAIN AND FEED INGREDIENT
RECEIVING SYSTEMS AT FEED
MILL/STORAGE
• Manual system
• Mechanic
• Gravity
• Pneumatic
WHAT TO DO WHEN RECEIVING
GRAIN & FEED INGREDIENTS?
1. Verify that it is the correct ingredient/grain
2. Check quantity
3. Check quality (physical and chemical
characteristics)
4. Document: Date, quantity, quality and
expiring date
5. Store at the correct location according to
grain/ingredient characteristics (micros &
medications in bags)
WHAT PHYSICAL
CHARACTERISTICS CAN BE
MEASURE?
• Grain and coproducts:
– Moisture content
– Color, texture & odor
– Density
– Particle size
– Visual presence of contaminants
(insects, mold, foreign material, etc)
– Use microscope if necessary!
WHAT CHEMICAL
CHARACTERISTICS CAN BE
MEASURE?
• Grain and coproducts:
– Protein, fat, starch, mineral, fiber content (wet
chemistry, NIR)
– Mycotoxins (ELISA or HPLC)
– Contaminants (Potassium hydroxide, indicator
of overcooked SBM)
– Contaminants to adultery (salt in fish meal)
RECEIVING AREA FOR GRAIN
AND FEED INGREDIENTS
• Dumping pit for bulk ingredients, dock or unloading area for ingredients in bags
• Dumping pit will have a screw conveyor or pneumatic system to handle the ingredients for storage or usage
• Storage for bulk grain (silos), bulk coproducts (SBM, DDGS (flat storage or warehouse) with unloading equipment
• Bag ingredient storage separated from finished product
• Liquids unload directly to tanks
Grain elevator in
the USA
Storage silos
Elevator
Dumping pit
Loading
bins for
trucks
HOW TO CHOOSE EQUIPMENT
FOR MATERIALS HANDLING?
• Based on the characteristics of the grain
and feed ingredients that will be
unloaded/loaded:
- Particle size
- Flowing characteristics
- Abrasive, stickiness, temperature,
corrosive, compaction, absorbs
water easily, can produce dust easily
EQUIPMENT USED FOR
MATERIALS HANDLING
• Gravity (spouts – important to have
minimal angles for proper flow)
• Mechanical (elevators, screw
conveyors, belt or drag conveyors)
• Pneumatics
BUCKET ELEVATORS
BUCKET ELEVATORS
Main Components
HEAD COMPONENTS
Base for motor
Belt and buckets Shaft
Cover
Pulley
Protection for abrasion
Unloading Inspection door
Inspection door
Door for cleaning
Loading opening
Adjustment for belt
Ajustment for elevator
Belt and buckets
Legs
BASE OF ELEVATOR
AVOID!
BUCKET ELEVATOR
Efficient Low losses due to friction Several sizes Can be use at lower
capacities Not noisy and low
maintenance Long life
Relative high cost Relative high installation
cost Maintenance difficulty Cannot be moved Can create mixture of
ingredients due to bad usage
DESVENTAJAS ADVANTAGES
HOW TO CALCULATE CAPACITY OF A ELEVATOR?
• Capacity per hour (kg/hr) = V x Vol x D x T
(V) Velocity = Velocity of the belt (m/min)
(Vol) Volumen = Volumen of the grain in every meter of belt (m3/m)
(D) Density = Density of the grain (kg/m3)
(T) Time = Conversion factor (60 minutes/hour)
CAPACITY OF ELEVATOR
(V) Velocity of the belt (m/min) =
Circumference of the pulley of the head del (meters) x RPM
Example:
Pulley with a diameter of 0.762 m y that rotates at 66 rev/min (RPM)
(V) =
(Diameter x 3.14) * Rotational speed (RPM)
(0.762 m * 3.1416)*66 RPM =
(V) = 158 m/min
MAXIMUM BELT VELOCITY
Inches cm RPM ft/min m/min
4.5 11.4 160 220 67
11 27.9 113 326 99
18 45.7 95 448 137
24 61.0 71 458 140
30 76.2 66 518 158
36 91.4 60 565 172
42 106.7 56 630 192
48 121.9 56 711 217
Pulley Diameter Belt velocity
For pellets and seed grain, reduce velocity by 20% to reduce any damage. Reduce 10 to 20% for mash or powder ingredients to avoid over filling the buckets.
CAPACITY OF ELEVATOR • (Vol) Volumen of the grain (m3/m) =
Volumen of the bucket (given by manufacturer or calculated ) / Nº of buckets in 1 meter of belt x filling factor
Example: - Bucket measurements = 30.5 cm x 15.2 cm x 10
cm= 0.0046539 m3 each one
- Distance center to center = 20.3 cm
Distance center to center 1 meter
CAPACITY OF ELEVATOR • (Vol) Volumen of the grain (m3/m) =
Volumen of the bucket (given by manufacturer or calculated ) / Nº of buckets in 1 meter of belt x filling factor
Example: - Bucket measurements = 30.5 cm x 15.2 cm x 10
cm= 0.0046539 m3 each one
- Distance center to center = 20.3 cm
- Filling factor = 90%
• (Vol) (m3/m) =
(0,0046539 m3 / 0,203 m) * 0,90 =
(Vol) = 0,020612 m3/m
GRAIN DENSITY
Type of
Grain
Density (lb/ft3 )
Density
(kg/m3 )
Corn 44.8 719
Sorghum 40.0 - 44.8 642 – 719
Soybean 48.0 771
Sunflower 19.2 308
Wheat 48.0 771
CAPACITY OF ELEVATOR
Capacity per hour (kg/hr) = V x Vol x D x T
Capacity (kg/hr) = 158 m/min x 0,020612 m3/m x 719 kg/m3 x 60
min/h
= 140,494 kg/hr
= 140 TPH
ANGLES FOR SPOUTS • Unloading height
Flowing Angle,
Height H tan = --------- = -- Distance D
DESIGN CONSIDERATIONS FOR CALCULATING ELEVATOR HEIGHT
Calculations for correct height for proper flow:
E = B + H E = B + D * tan E = Elevator height H = Difference height elevator
and bin B = Bin height D = Distance (horizontal)
between elevator and unloading inside bin
Flowing Angle,
DESIGN CONSIDERATIONS FOR CALCULATING ELEVATOR HEIGHT
• ELEVATOR HEIGHT DIFFERENCE WITH BIN
Minimal Angle for Flowing: Elevator Height (E):
Dry Grain 37° E = B + 0.754 * D
Wet Grain 45° E = B + D
Pellets 45 ° E = B + D
Soybeans 60° E = B + 1.732 * D
Mash (powder) 60° E = B + 1.732 * D
DESIGN CONSIDERATIONS FOR CALCULATING ELEVATOR HEIGHT
• Example:
Determine the elevator height to unload soybeans by gravity into a bin (Height (B) = 10 m that is located at 12 m (D) from the elevator.
Unloading angle for soybeans, = 60° Horizontal distance, D = 12 m Bin height, B = 10 m Elevator Height (E) = B + 1.732 * D = 10 m + 1.732 * 12 m E = 30.8 m
AVOID THESE DESIGNS FOR DOWNSPOUTS!!
DESIGN CALCULATIONS FOR DOWNSPOUTS
Calculation of downspout from elevator to bin (L):
L = (D2 + H2)1/2
Flowing Angle,
DESIGN CALCULATIONS FOR DOWNSPOUTS
• Example:
Determine the height of the elevator (H) and the length of the downspout (L) if the elevator is located a 7.6 m horizontally from the base of the bin for proper handling corn (dry).
Angle for flowing dry corn, = 37° Horizontal distance, D = 7,6 m Using formulas from table H = 0.754 * D
DESIGN CONSIDERATIONS FOR CALCULATING ELEVATOR HEIGHT
• ELEVATOR HEIGHT DIFFERENCE WITH BIN
Minimal Angle for Flowing: Elevator Height (E):
Dry Grain 37° E = B + 0.754 * D
Wet Grain 45° E = B + D
Pellets 45 ° E = B + D
Soybeans 60° E = B + 1.732 * D
Mash (powder) 60° E = B + 1.732 * D
DESIGN CALCULATIONS FOR DOWNSPOUTS
• Example: Determine the height of the elevator (H) and the length
of the downspout (L) if the elevator is located a 7.6 m horizontally from the base of the bin for proper handling corn (dry).
Angle for flowing dry corn, = 37° Horizontal distance, D = 7,6 m Using formula from table H = 0.754 * D H = 0.754 * 7.6 m H = 5.7 m Length of downspout L = (D2 + H2)1/2
L = ((7.6 m)2 + (5.7 m)2)1/2 L = 9.5 m
CAPACITY TABLE FOR DOWNSPOUTS
Capacity is for dry clean grain for each diameter. Velocity is calculated for an angle of 45º for 3 m or more with an average between 280 to 327 m/min.
TABLE FOR GRAIN VELOCITY INSIDE DOWNSPOUT (ft/min)
35º 40º 45º 50º 55º 60º 65º 70º 75º 80º 85º 90º
5' 400 524 618 700 770 830 885 935 975 1010 1050 1075
10' 570 742 875 990 1090 1180 1255 1320 1380 1435 1485 1520
15' 695 908 1070 1210 1335 1440 1530 1615 1690 1755 1820 1860
20' 805 1047 1235 1400 1540 1665 1770 1870 1950 2025 2100 2150
25' 899 1170 1380 1560 1725 1860 1975 2085 2180 2265 2340 2400
30' 985 1280 1510 1710 1890 2040 2165 2285 2390 2480 2570 2335
40' 1135 1480 1750 1975 2180 2355 2500 2640 2760 2865 2970 3040
50' 1270 1655 1950 2210 2440 2635 2800 2955 3090 3210 3320 3400
60' 1390 1810 2140 2420 2670 2880 3065 3240 3390 3520 3640 3720
70' 1500 1960 2310 2615 2880 3110 3315 3500 3660 3800 3930 4025
80' 1605 2090 2470 2795 3080 3330 3540 3740 3905 4055 4200 4295
90' 1705 2200 2620 2960 3275 3535 3760 3965 4150 4310 4460 4550
100' 1795 2340 2765 3120 3450 3720 3960 4180 4370 4540 4700 4800
125' 2005 2620 3090 3500 3860 4165 4440 4680 4890 5080 5250 5370
150' 2200 2865 3390 3835 4225 4560 4850 5120 5450 5560 5750 5880
Flow (Repose) Angle D
ow
nsp
ou
t L
en
gth
(ft
)
Angles of 28º and grain velocities above 1750 ft/min should be avoided
GRAIN VELOCITY REDUCTORS
VELOCITY REDUCTORS FOR PNEUMATIC SYSTEMS
NO!
Use cyclones!
UNLOADING LADDER FOR PELLETS OR GRAIN SEEDS
SCREW CONVEYORS
TYPES OF SCREW CONVEYORS
• Tube conveyors (Close) • Portable
• Unloading grain bins
• Loading grain bins or handling
• Sweeping for cleaning bin
• Moving grain or feed in bulk transportation
• Mixing purposes
• U conveyors (Open) • Indoor for moving grain or feed
• Maximum angle is 35°
CLOSE SCREW CONVEYORS
• More economical
• Need to work a full capacity, if not can damage pellets or grain
• Limits incline angle, loose capacity
• Can load/unload at any location a long the conveyor
Cross Section
PORTABLE CLOSE CONVEYORS
• Loading grain bins
• Typical diameter: 6 – 12 in
(15 – 31 cm)
• Length between: 8.8 – 26 m
• Maximum capacity 115 TPH
• Maximum angle 45°
CLOSE CONVEYOR
TubE
Nota: Minimal opening is equal to diameter of tube
CALCULATION OF CAPACITY FOR CLOSE CONVEYOR
(D2 – d2) * P * RPM Theoretical Capacity (m3/h) = ------------------------ 36.6
D = Diameter of conveyor, cm
d = Diameter of shaft, cm
P = Pitch (Distance between flights, cm
RPM = Rotational speed of conveyor, rev/min
Real Capacity depends on inclined angle, speed, friction
Real Capacity = 30 to 50% Theoretical Capacity
HOW TO CALCULATE THE POWER NEEDED FOR A CONVEYOR
C * L * W * F Power (HP) = ---------------- 33,000
C = Capacity of conveyor (ft3/h)
L = Length of conveyor (ft)
W = Bulk density of product (lb/ft3)
F = Factor for product (table)
ADJUST FOR REAL POWER WITH TABLE
TABLE OF DENSITY AND FACTOR FOR CONVEYORS
Product
Density (W) lb/ft3
Factor (F)
Barley 38 0.4
Corn 45 0.4
Oats 26 0.4
Rice 36 0.4
Soybeans 45-50 0.5
Wheat 48 0.4
ADJUSTMENT TABLE FOR POWER NEEDED FOR A
CONVEYOR
If calculated power is:
Real power is:
<1 HP = 2 * HPC
1 HPC <2 HP = 1.5 * HPC
2 HPC <4 HP = 1.25 * HPC
4 HPC <5 HP = 1.1 * HPC
HPC 5 HP = 1.0 * HPC
DESIGN TABLE FOR CAPACITY AND POWER FOR CONVEYORS
Conveyor
diameter (in)
Conveyor
Speed (rpm) TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft
4 900 14 0.6 13 0.9 12 0.9 11 1.0 7 0.8
6 600 38 1.0 34 1.5 32 1.6 30 1.6 18 1.3
8 450 55 1.4 50 2.2 47 2.2 44 2.3 26 1.9
10 360 83 2.0 74 3.1 71 3.2 66 3.2 39 2.5
12 300 113 2.5 102 3.9 97 4.0 90 4.0 54 3.2
14 260 156 3.4 140 5.3 134 5.4 124 5.5 74 4.3
16 225 201 4.4 181 6.8 172 7.0 160 7.1 96 5.6
90
Dry grains (corn, wheat,
rice, sorghum)
Inclined Angle
0 25 35 45
Source: MWPS-13 T2-3
1 ft = 0.30 m
DESIGN TABLE FOR CAPACITY AND POWER FOR CONVEYORS
Conveyor
Diameter (in)
Conveyor
Speed (rpm) TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft
4 900 8 1.7 8 1.8 7 1.7 7 1.8 4 0.8
6 600 23 2.8 20 3.0 19 3.0 18 2.9 11 1.3
8 450 33 3.9 30 4.4 28 4.2 26 4.1 16 1.9
10 360 50 5.6 45 6.2 42 6.1 39 5.8 24 2.5
12 300 68 7.0 61 7.8 58 7.6 54 7.2 32 3.2
14 260 93 9.5 84 10.6 80 10.3 74 9.9 44 4.3
16 225 121 12.3 109 13.6 103 13.3 96 12.8 57 5.6
Wet corn (25%) Inclined Angle
0 25 35 45 90
Fuente: MWPS-13 T2-3
1 ft = 0.30 m
SBM and Mash Feed
Conveyor
Diameter (in)
Conveyor
Speed (rpm) TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft TPH HP/10 ft
4 900 13 0.6 11 0.9 11 0.9 10 1.0 6 0.8
6 600 34 1.0 31 1.5 29 1.6 27 1.6 16 1.3
8 450 50 1.4 45 2.2 43 2.2 40 2.3 24 1.9
10 360 75 2.0 68 3.1 64 3.2 60 3.2 36 2.5
12 300 103 2.5 93 3.9 88 4.0 82 4.0 49 3.2
14 260 142 3.4 128 5.3 121 5.4 113 5.5 67 4.3
16 225 183 4.4 165 6.8 156 7.0 145 7.1 87 5.6
Inclined Angle
0 25 35 45 90
Fuente: MWPS-13 T2-3
DESIGN TABLE FOR CAPACITY AND POWER FOR CONVEYORS
1 ft = 0.30 m
SCREW CONVEYORS
• Initial costs is economical
• Can be use horizontally, vertically and inclined
• Can be use for mixing purposes
• Can have multiple inlets and outlets
• Maintenance cost is economical
Advantages
SCREW CONVEYORS
• Can damage the product
• There is product accumulation at the outlets
• Cannot be self-cleaningh
• Are not efficient
• Can only be use in a straight line
DISADVANTAGES
DRAG CONVEYORS
DRAG CONVEYORS
• Initial cost is not that expensive
• Can move product vertically and horizontally
• Can move product in 90 ° angles
• Self-cleaning capacity Se auto-limpian
• Minor damage to product
ADVANTAGES
DRAG CONVEYORS
• Are not that efficient
• Pallets will wear out fast
• Have difficulty moving dense products
• Maintenance is more difficult
DISADVANTAGES
PNEUMATIC SYSTEMS
Positive Displacement
POSITIVE PNEUMATIC SYSTEMS
ADVANTAGES:
• Do not need filters
• Can unload product at any point
• Can be use to move high dense products at high pressure
DISADVANTAGES:
• Use a lot of energy and produce heat
• Can dry the product
• Due to high velocity can damage product
• Difficult to have multiple inlet points
PNEUMATIC SYSTEMS
Negative Displacement
NEGATIVE PNEUMATIC SYSTEM
ADVANTAGES: • Negative pressure controls fines and dust • Can have multiple inlet points • Can be use for products sensible to heat
DISADVANTAGES: • Are not efficient • Maintenance is difficult • Blower needs filter to avoid dust entry • Only one outlet point
SUMMARY
• Know the characteristics of the product
• Choosing equipment based on the volume of movement
• Equipment does need to damage product to be efficient
• Do not overload equipment
