Batching and Mixing Charles Stark North Carolina State University
Batching and Mixing
Charles StarkNorth Carolina State University
Batching & Mixing Objective
Accurately weigh each ingredientMinimize batching timeProduce a feed that has a uniform distribution
of nutrients and medications
Ingredient Factors
Particle size and shape
Density
Electrostatic charge
Hygroscopicity
Flowability Source: IMC 1995
Particle Size Specification
Ingredients & MineralsSupplier specificationsCustomer specifications Example SBM, DDGS (600 1200 microns)
Specifications based on screen size Thru a US # _____
PremixesCarrierParticles per gram
Source: IMC 1995
Feed Segregation
Segregation occurs primarily as a result of differences in particle size, the difficulty of mixing multiple components can be reduced by making the sizes of the components as close as possible and also by reducing the absolute size of the particles.
Source: IMC 1995
Ingredient Characteristics
Particle sizeShapeFlatRound
DensityWheat MiddsGround CornSBMLimestone
Source: IMC 1995
Particle Differences Large Particles - For coarse particles, the
attractive force between two particles in contact is small compared with the weight of a particle, leading to a free flowing material.
Small Particles - If the particle size is reduced, the weight of a particle falls more rapidly than the attractive force between the particles, and eventually the stage is reached where the particles stick together. Segregation is then prevented, because particles are no longer free to move relative to each other.
Source: IMC 1995
Feed Mill Designs
Pre-batch grind Post-mix grind
Post-batch grindPost-pellet blend
Micro Bin SystemsTote Bag SystemsScalesMajorMinor
Weigh BuggyLiquid Pumps & Meters
Batching Equipment
Scales
Batching Scale Fill Test
Major & Minor ScalesFill 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 Micro SystemMultiple Hopper Scale Single Hopper Scale
Batching - Totes
Totes & Scales Tote Transfer
Liquid Ingredients
Self Contained System Tank & Dike System
Liquid Addition Layout
Liquid Addition Equipment
Meters Pumps
Mass Flow System Liquid ComponentCoriolis Meter
Mass Flow System Coriolis Meter
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
Spray Here
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
MIXING EQUIPMENT
Automation System
Automation HardwarePC
ServerPLC
PLC
PLC
PLC Cards/Modules
PLC Computer Inputs
Theromcouple
Hand Add Buttons
Micro Switch
Scale Indicator
PLC Outputs
VFD
Motor Starter
Batch Production Report
Recommended mix times
Mixer Dry Mix Wet MixPaddle 3 3Twin Shaft Paddle 0.5 1Double Ribbon 1-2 2-3Twin Shaft Ribbon 0.75-1 2Vertical 5-10 5-10
Source: Froetschner, 2007
Mixer Design Factors
DimensionsShort x WideLong x Narrow
Ribbon/Paddle AngleRibbon Width(s)Ribbon Tip SpeedTotal Surface Area
Mixer Sizes
200 CF Mixer
Feed (lbs/cft)35 - 7000 lbs40 8000 lbs45 9000 lbs
Horizontal Ribbon Mixer
Ribbon mixer Multiple ribbons
Double ribbon Single shaft
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
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
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 ZonesMain
Mixing
Zone
Main
Mixing
Zone
Main
Mixing
Zone
Vertical Mixer
Mixer-Problems
Liquid Spray Nozzle Material Build up
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
Distribution of weighing errors
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 scalesbecause 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 lbsgives a call/scale resolution of 20, where as a call for the same 100 lbs on a scalewith a resolution of 2 lbs gives a ratio of 50.
Mixer Uniformity Analysis
Mixer MarkersSingle nutrient/ingredient Salt Synthetic Amino Acids (Lysine or Methonine) Dry Mix Uniformity
EconomicalAccurate 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
Feed Quality Assurance Mixer Test 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.
Sample mixer
Sample surgeSample 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 - QuantabFold 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 100mean
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 0.18
10 0.18
STANDARD DEVIA 0.02MEAN 0.19
COEFFICIENT OF VARIATION (CV) 9.65
Micro Tracer Rotary Detector Method
Materials Rotary Detector. Scale. Demagnetizer. Heating plate. Developing Solution. Filter paper 7.5 mm Grinder for pelleted feed
Test Method Weigh 100 g sample Place filter paper on the spindle
of the rotary magnet. Transfer the sample of feed to
the top hopper of the Rotary Transfer the Microtracer to a
scoop, demagnetize, then disperse over a large wetted filter paper on an aluminiumplate. Then dry on hot plate to develop spots. Count the spots.
Source: www.microtracers.com
MicroTracter Rotary Detector
Source: www.microtracers.com
FS-Red/ Natural Yellow Spots Developed with 50% Water and Alcohol
Source: www.microtracers.com
Mixer Uniformity Evaluation
CV RATING CORRECTIVE ACTION
< 10% Excellent None
10-15% Good Increase mixing time by 25-30%
1520% 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 RPMs
Double Ribbon Mixer Worn Ribbons
Double Ribbon Mixer Wrong Rotation
Double Ribbon Mixer Build-Up
Questions