Batching and Mixing
Peter Ferket
Charles Stark
North Carolina State University
Batching & Mixing Objective
 Accurately weigh each ingredient
 Minimize batching time
 Produce a feed that has a uniform distribution
of nutrients and medications
EQUIPMENT
Batching Equipment
 Micro Bin Systems
 Tote Bag Systems
 Scales
Major
Minor
 Weigh Buggy
Scales
Batching – Scale Fill Test
 Major & Minor Scales
 Fill test evaluates full
range of load cells
 Add test weights
 Record weight
2/3
 Remove weights
 Fill scale to 1/3 capacity
 Add test weights
 Record weight
1/3
200 lb
 Remove weights
 Fill scale to 2/3 capacity
 Add test weights
 Record weight
 Document results
Batching – Manual Weighing
Weigh Buggy
Platform Scale
Feed Mill Designs
Pre-batch grind
Post-batch grind
Post-mix grind
Post-pellet blend
Batching – Micro System
Multiple Hopper Scale
Single Hopper Scale
Batching - Totes
Totes & Scales
Tote Transfer
Batching Sequence
Batching System
Computer draws multiple
bins to the major scale.
Micro Scale
Major
Scale
Minor
Scale
Major Scale:
Computer switches to one
bin and jogs at the end of
the each ingredient.
Major Ingredients
Corn/Wheat
SBM
Midds
DDGS
Batching Sequence
Batching System
Major
Scale
Minor
Scale
Minor Scale Fill:
Micro Scale
Computer draws single
bins to the minor scale
and jogs at the end of the
each ingredient.
Minor Ingredients
Dical
Limestone
Salt
Lysine
Batching Sequence
Batching System
Micro Scale Fill:
Micro
Scale
Major
Scale
Minor
Scale
Computer draws single
bins to the micro scale and
jogs at the end of the each
ingredient.
Micro Ingredients
Vitamins
Trace Minerals
Medications
Amino Acids
Batching Sequence
Batching System
Scale Considerations:
Micro Scale
Major
Scale
Minor
Scale
Major Scale 80-90%
Minor Scale 10-15%
Micro Scale < 5%
Batching Sequence
Batching System
Major Scale
Discharges First
Micro Scale
Major
Scale
Minor
Scale
Fills the dead space
between the ribbons
and tub.
Batching Sequence
Batching System
Micro Scale
Major
Scale
Minor
Scale
Minor Scale Discharges
after a 5-10 second
delay
Minor ingredients mix
with the major
ingredients
Batching Sequence
Batching System
Micro Scale Discharges
after a 0-5 second delay
Micro Scale
Major
Scale
Minor
Scale
Micro tub or scales open
and the material is
transferred with a drag
conveyor
Mixing Time
Batching
Horizontal Double Ribbon
Batching System
30-60 second Dry Mix
Micro Scale
Major
Scale
Minor
120-180 second Wet Mix
Liquid Addition
Scale
Volumetric (meter)
Gravimetric (weighed)
Liquid Ingredients:
Fat
Molasses
Choline
Amino acids
Batching Sequence
Batching/Mixing System
Mixer opens and
material drops to a
surge hopper
Micro Scale
Major
Scale
Minor
Scale
Discharge Process
Batch Cycle
Batch Cycle – 4 mins
Weighing 2 min
Discharge
1 min
Mixing 3 min
Weighing 2 min
Discharge
1 min
Mixing 3 min
Automation System
Batch Production Report
MIXING EQUIPMENT
Horizontal Ribbon Mixer
Double Ribbon Mixer – Mixing Zones
Feed Flow
Main Mixing Zone
Main Mixing Zone
Typical mix time = 3-4 min
Double Ribbon Horizontal Mixer
Paddle Mixer
Paddle Mixer – Mixing Zones
Feed Flow
Main Mixing
Some
Main Mixing
Mixing
Main Mixing
Some
Mixing
Main Mixing
Horizontal Paddle Mixer
Rotating Drum Mixer – Mixing Zones
Drum Mixer
Ribbon Mixer - Counterpoise
Ribbon Mixer – Counterpoise Mixing Zone
http://www.hayes-stolz.com/
Forberg Fluid Bed Mixer
Forberg Mixer
Vertical Mixer
Vertical Mixer – Mixing Zones
Main
Main
Mixing
Mixing
Zone
Zone
Main
Mixing
Zone
Vertical Mixer
Mixer Problems
Material on ribbons
Material on paddles
Batching & Mixing Problems
Fat sprayed on ribbon and
shaft
Fat lumps created by poor
liquid application and mixing
MIXER UNIFORMITY ANALYSIS
Factors Affecting Uniformity
 Particle Shape
 Spherical, square, flat
 Particle Size
 Different particle size can separate during the handling
process
 Density
 Heavy particles may settle out during conveying and
discharge to a bin
 Static Charge
 Particles will adhere to equipment if not properly grounded
 Hydroscopicity
 Vitamins or Feed Additives may absorb water
 Adhesiveness
 Fats or molasses may adhere to equipment
What Represents the Goal of Mixing?
Segregated
Mix
Perfect Mix
Random Mix
Weighing Ingredients Correctly?
Weighing Accuracy
 Feed mills overdose their ingredients by about 1.5%
 Average inaccuracy in dosing within feed mills ranges from
0.7 - 13.0%
 About 85% of the calls are weighted with an error of ± 5% and
about 90% are within ± 10% of called weight
Distribution of weighing errors
Overdosing and weighing errors
error within mill (a-n) across all observations
Are You Weighing Ingredients Correctly?
Weighing Precision
 Variation in weighing within ingredients, expressed
as Coefficient of Variation (CV)
 Weighing CV ranges on average of about 5% (0.6 11% CV)
Causes of Weighing Variation
 Hand-weighing ingredients
 People tend to overdose by about 1% when ingredients are weighed by hand
 Micro-ingredients and premix dose errors
 Micro-ingredients scales seem to be more variable than macro-ingredient scales
because of the size of the call
 Descrepancies between call size and scale resolution
 Average weighing discrepancies in feed mill is about 2% but can range up to 20%
 For example, requesting 11.3 lbs of an ingredient when the scale has a resolution
of only 2 lbs.
 Ratio of call size to scale resolution
 Weighing errors and CV decreases as the call size to scale resolution increases.
For example, a call for 100 lbs to be weighed on a scale with a resolution of 5 lbs
gives a call/scale resolution of 20, where as a call for the same 100 lbs on a scale
with a resolution of 2 lbs gives a ratio of 50.
Weighing errors and CVs for different call
size to scale resolutions
Call Size:Scale
Resolution Ratio
Weighing Error, %
CV, %
10
4.0
11.4
100
1.0
3.6
1000
0.3
1.1
Experimental Data
Mixer Uniformity Analysis
 Mixer Markers
 Single nutrient/ingredient
 Salt
 Synthetic Amino Acids (Lysine or Methonine) Dry Mix Uniformity
 Economical
 Accurate and precise at inclusion level
 Test twice per year
 Ten samples from the same batch of feed
 Sample mixer or a point closest to the
discharge
Mixer Uniformity Analysis
 Sampling Points
Mixer or Surge samples provides information on
dead spots in the mixer or mixer maintenance
issues
Sampling during the discharge process provides
representative samples of the feed as it moves
through the system.
Feed Quality Assurance – Mixer Test
 Sample mixer
OR
 Sample surge
OR
 Sample discharge
conveyor
Mixer Uniformity Analysis - Quantab™
Mixer Uniformity Analysis - Quantab™
 Weigh 10 gram
sample of feed into
a dish
 Scale +/- 0.1 g
Mixer Uniformity Analysis - Quantab™
Fold filter paper to create a cone
Mixer Uniformity Analysis - Quantab™
 Measure out 90 ml
of HOT distilled
water
 SAFETY
Hot Water Burns!!
Mixer Uniformity Analysis
 Mix sample and water
for 30 sec wait and
re-mix for 30 sec.
 Place filter paper
cone in cup
 Place Quantab strip
into the filter cone
 Indicator strip at the
top will turn black
when complete
Mixer Uniformity Analysis - Quantab™
 Read highest point
on the strip
 Determine NaCl
level based on the
calibration chart on
the bottle.
 Multiple by 10
(10:1 dilution)
Mixer Uniformity Analysis Calculations
 Calculation of Mixer CV
Mean of samples
Standard deviation of samples
CV % = standard deviation x 100
mean
Mixer Uniformity Analysis Calculations
NAME:
ADDRESS:
SAMPLE:
DATE:
QUANTAB READINGS
1
2
3
4
5
6
7
8
9
10
0.20
0.21
0.22
0.17
0.17
0.18
0.20
0.17
0.18
0.18
STANDARD DEVIATION
0.02
MEAN
0.19
COEFFICIENT OF VARIATION (CV)
9.65
Mixer Uniformity Evaluation
CV
RATING
CORRECTIVE ACTION
< 10%
Excellent
None
10-15%
Good
Increase mixing time by 25-30%
15-20%
Fair
20% +
Poor
Increase mixing time by 50%, look for worn
equipment, overfilling, or sequence of
ingredient addition
Possible combination of all the above
Consults extension personnel or feed
equipment manufacturer
Double Ribbon Mixer – RPM’s
Double Ribbon Mixer – Worn Ribbons
Double Ribbon Mixer – Wrong Rotation
Double Ribbon Mixer – Build-Up
Questions