Batching and Mixing
Peter Ferket
Charles Stark
North Carolina State University
Batching & Mixing Objective
Accurately weigh each ingredientMinimize batching timeProduce a feed that has a uniform distribution
of nutrients and medications
EQUIPMENT
Micro Bin SystemsTote Bag SystemsScales
MajorMinor
Weigh Buggy
Batching Equipment
Scales
Batching – Scale Fill Test
Major & Minor Scales Fill test evaluates full
range of load cells Add test weights
Record weight Remove weights Fill scale to 1/3 capacity Add test weights
Record weight Remove weights Fill scale to 2/3 capacity Add test weights
Record weight
Document results
1/3
2/3
200 lb
Batching – Manual Weighing
Weigh Buggy Platform Scale
Feed Mill Designs
Pre-batch grind Post-mix grind
Post-batch grindPost-pellet blend
Batching – Micro System
Multiple Hopper Scale Single Hopper Scale
Batching - Totes
Totes & Scales Tote Transfer
Major Scale
Minor Scale
Micro Scale
Batching SystemMajor Scale:
Computer draws multiple bins to the 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
Major Scale
Minor
Scale
Micro Scale
Batching System Minor Scale Fill:
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
Major Scale
Minor Scale
Micro Scale
Batching System Micro Scale Fill:
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
Major Scale
Minor Scale
Micro Scale
Batching System
Scale Considerations:
Major Scale 80-90%
Minor Scale 10-15%
Micro Scale < 5%
Batching Sequence
Major Scale
Minor Scale
Micro Scale
Batching SystemMajor Scale Discharges First
Fills the dead space between the ribbons and tub.
Batching Sequence
Major Scale
Minor Scale
Micro Scale
Batching SystemMinor Scale Discharges after a 5-10 second delay
Minor ingredients mix with the major ingredients
Batching Sequence
Major Scale
Minor Scale
Micro Scale
Batching SystemMicro Scale Discharges after a 0-5 second delay
Micro tub or scales open and the material is transferred with a drag conveyor
Batching Sequence
Major Scale
Minor Scale
Micro Scale
Batching System
Liquid Addition
Volumetric (meter)
Gravimetric (weighed)Liquid Ingredients:
Fat
Molasses
Choline
Amino acids
Mixing Time
Horizontal Double Ribbon
30-60 second Dry Mix
120-180 second Wet Mix
Batching
Major Scale
Minor Scale
Micro Scale
Batching/Mixing System
Discharge Process
Mixer opens and material drops to a surge hopper
Batching Sequence
Weighing 2 min
Discharge 1 min
Mixing 3 min
Weighing 2 min
Discharge 1 min
Mixing 3 min
Batch Cycle – 4 mins
Batch Cycle
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
Main Mixing
Main Mixing
Main Mixing
Some
Mixing
Some
Mixing
Horizontal Paddle Mixer
Rotating Drum Mixer – Mixing Zones
Mai
n Mix
ing Z
one
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
Mixing
Zone
Main
Mixing
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?
Perfect Mix
Random Mix
Segregated 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.
Experimental Data
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
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 PointsMixer 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 mixerOR
Sample surgeOR
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
SAFETYHot 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 CVMean of samplesStandard deviation of samples
CV % = standard deviation x 100
mean
Mixer Uniformity Analysis CalculationsNAME: DATE:ADDRESS:SAMPLE:
QUANTAB READINGS
1 0.202 0.213 0.224 0.175 0.176 0.187 0.208 0.179 0.1810 0.18
STANDARD DEVIATION0.02MEAN 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 Increase mixing time by 50%, look for worn equipment, overfilling, or sequence of ingredient addition
20% + Poor Possible combination of all the aboveConsults 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