batching and mixing 2011

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


Weigh 10 gram sample of feed into a dish

Scale +/- 0.1 g

Mixer Uniformity Analysis - QuantabFold filter paper to create a cone


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


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


FS-Red/ Natural Yellow Spots Developed with 50% Water and Alcohol


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

batching and mixing 2011

Documents