Mixing
What is the mixing process?
Start mixer without materials
Ingredient weighing
Dry ingredients load - bulk ingredients are ground before going to mixer, micro ingredients go straighter to mixer
Wet ingredients load
and then discharge ingredients
Conditioning is?
Preparation of diet for forming in a pellet diet
Process aided by heat and moisture
the process of preparing the diet for forming into pellets
Types of extruders?
Ram or Piston
Roller
Screen
Screw - low or high shear
extrusion cooking is?
cooked material forced through a opening
if temperature over 100C water boils on exit creating internal pressure causing expansion
used for ingredients
Near infrared technology?
Uses infaared light reflected on or through grain or finished feed
measure the absorbance/reflectance of different chemical bonds
can measure: Moisture, fat, protein, starch, particle size
Types of mixers
Horizontal mixers = Ribbon, Paddle, twin-shaft
Vertical mixers
continuous mixers
Low vs High pressure steam?
Higher pressure = more energy
boiler are regulated based on safety requirements
Single screw vs Twin Screw?
Single screw = lower capital costs
Twin screw = Better thermal transfer, enhanced mixing, low to high moisture, low to high lipid, versatile
Liquid addition is?
Most liquids added into mixer
Heat sensitive materials added after cooling
too much fat will destroy pellet quality so added after pelleting or extrusion
addition of enzymes, fats, water, and vitamins
NIRS pros
Quick, non destructive, minimal to no sample preparation, cheap to run samples
Ribbon vs Paddle vs Twin-shaft
Ribbon = Outer and inner ribbons that move in opposite directions, short mixing time, 40-90% capacity, ideal clean out
Paddle = best for difficult materials and abrasive ingredients, poor side-side mixing, poor corner mixing
Twin-shaft = most versatile, rapid blending, can accommodate low fill levels
Reasons to condition?
Lubricate for faster production
lubricate to extend die life
lubricate to reduce energy costs
gelatinize starch for nutritional value
increase pellet quality
Preconditioner is?
Common in TVP, pet food, animal and fish feed to hydrate and increase cooking time
monitor temp of mix exiting the preconditioner
Manipulate parameters to affect product quality
Vacuum coating is?
Designed to increase fat up to 40% for intensive aquaculture production
used in a range of applications
place pellets/collects in vacuum chamber, evacuate air, inject liquids, release vacuum
NIRS cons
Expensive to acquire machine, calibrations are complex, ingredient and final product variation can affect calibration effectiveness
Vertical mixers vs Continuous mixers
Vertical = Cheap investment, low maintenance, small footprint, common for small on farm mills, ineffective for liquid inclusion, poor clean out, best for cattle TMR
Continuous = Weigh, charge, mix, discharge are all simultaneous, not as accurate as batch systems
What is a retentioner?
Used to extend the amount of time a product is heated
reduce microbial load
increase pellet quality
Hold the product at conditioned temperature for an additional 30-120 seconds
Raw materials is?
Starch type and content
protein type and content
lipid content
Water content
Particle size
Process control is?
The primary type of automation
control room as well as locations in the plant
batching and process parameters
control feed rate to maximize efficiency
Incline NIRS
Most NIRS is table top and requires operators to take samples and analyse
What impacts mixer performance?
Particle size distribution
density of solids
Liquid application
Fill level
Poorly maintained equipment
Ingredient accumulation
Expanders are?
used to increase pellet quality, pellet output and digestibility
But more difficult to manage than standard conditioning
Extrusion parameters is?
Screw speed, throughput, thermal input, when and where you add moisture, melt temperature, pressure, residence time, shear, viscosity, torque, residence time
Data base management is?
Feed mills handle a great deal of product and all is subject to traceability and quality control
Requires active data base management
quality control/ quality assurance programs require active management
Opportunities in Digital Ag in the feed mill
The feed industry needs people to manage: process control systems, management of data bases, and upgrading and adopting additional automation in the plant