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