hardening and storage lecture2009

7/30/2019 Hardening and Storage Lecture2009

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Rapid Hardening Systems

By R.C.Greener


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Which Would You Rather Buy?

A or B


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Benefits of Quick Hardening

Better Freshness and Quality

Smoother Ice Cream Texture

Less Carton Damage in Storage and Distribution

Process

Less Chance of Product Skinning

Better Ice Cream Consistency Regardless of

Package Size or Shape Lower Labor and Handling Costs

Inventory reduction - Ship directly from

Hardener


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Costs to Harden Rapidly

More energy

Higher Capital Investment Increased product shrinkage if design

improper


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Percentage of H2O Frozen atVarious Draw/Fill Temperatures

Draw Temp % H2O Frozen

+25oF 33.0

+24

o

F 41.0+23oF 47.0

+22oF 52.0

+21oF 56.0

+20oF 59.0

-15oF 90.0


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Two Types of Hardening

Open Loop Closed Loop

Ice Cream Manufacturer

Purchases Refrigeration

Ice Cream Manufacturer

Refrigerates with

Self Contained System


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Common

Hardening Methods

CryogenicAir

Convection

Comb. Plate/

Air ConvectionPlateImmersion

Open Loop Closed Loop


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AdvantagesofCryogenic Hardening

Lowest retention time for ice cream

novelties & cakes Excellent ice cream texture

Allows surface setting of novelty item prior

to wrapping Superior overall quality for cake items


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DisadvantagesofCryogenic Hardening

Very expensive on a cost/lb basis

Cost is proportional to location

cryogenic medium processing Unit must meet sanitation demands

Process requires expensive

production room area


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How Immersion & Plate Systems Harden

Ice CreamEvaporative

Condenser

MechanicalRefrigeration

System

Heat Transferred by

Direct Conduction from

Product to Refrigerant

Energy Transferred from

Refrigerant to Atmosphere


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Advantages ofImmersion Hardening

Best method to harden stick novelties

Rapid hardening with resultant minimumretention times

Automation allows high production rates

High product quality Efficient heat removal process


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Disadvantages ofImmersion Hardening

Single item process

Requires expensive production room area

Must meet sanitation requirements Some units subject to high waste water

demands

Product shrinkage through process is relativelyhigh

High capital expense for single itemmanufacture


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Advantagesof Plate Hardener

Makes near perfect squares and rectangles on95% of production

Rapid hardening with resultant minimumretention times

Heat removal via conduction is very efficient

Requires minimal space in low cost ambient

warehouse environment Low production shrinkage through hardening

process


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Disadvantagesof Plate Hardener

Very limited item utility

Approximately 5% of product has shape

irregularities High capital cost in plants where all volume can

not be hardened by plate process

Safety issue because refrigerant is in movinghollow plate

Requires low refrigerant temperature


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How Air Convection Hardens

Ice Cream

Mechanical

Refrigeration

System

CoilEvaporative

Condenser

Cold

Air

Warm

Air

Conduction from

Product to Air

Conduction From

Product to Refrigerant

Conduction from

Refrigerant to

Atmosphere


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Air Convection Significance

Used for Hardening over85% of IceCream in US.

Used by over95% of Ice Cream

Manufacturers in US


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Important Facts aboutConvection Hardening

Product Draw or Fill Temperature

Package Orientation during HardeningProcess.

Laminar Air Flow Vs. Turbulent air flow

Air Vs. Heat Removal IndexTemperature

Product Spacing


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Importance ofDraw/Fill Temperatures

Draw Temp % H2O Frozen

+25oF 33.0

+24oF 41.0

+23oF 47.0

+22oF 52.0

+21oF 56.0

+20oF 59.0

-15oF 90.0


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Air Flow Perpendicular to PakLength

Package: 4 56 oz.

Flavor: Choc. Peanutbutter cup.

Air Temp.: -25o F

Air Velocity: 1000 FPM

Core Temp In: +20.3o F

Core Temp Out: -0.4o F

Retention Time =

5 Hr 48 Min


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Air Flow Parallel to Pak Length

Package: 4 56 oz.

Flavor: Choc. Peanutbutter cup.

Air Temp.: -25o F

Air Velocity: 1000 FPM

Core Temp In: +19.8o F


Retention Time =

4 Hr 18 Min


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Draw Temp vs. Hardening Times

Package: 4 56 oz. SqRd

Flavor: Pumpkin Crme

Air Temp.: -23o F

Air Velocity: 1000 FPM Core Temp In: +23.2o F


Retention Time =

5 Hr 28 Min

Package: 4 56 oz. SqRd

Flavor: Pumpkin Crme

Air Temp.: -23o F

Air Velocity: 1000 FPM Core Temp In: +19.3o F


Retention Time =

4 Hr 4 Min


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Laminar vs Turbulent Air Flow

Definitions:

Laminar Flow =Streamline flow in a viscous fluid neara solid boundary.

Turbulent Flow =Fluid flow in which the velocity at a

given point varies erratically in magnitude anddirection.


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The requirement for an efficient air distributionsystem is

Conversion from Turbulent Flow

to

Laminar Flow


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What Causes Turbulent Flow?

1. Fans and other mechanical methods of moving air.

2. Obstructions to normal air flow.

3. Merging air patterns.

Advantages:

Can provide excellent heat removal when hardening.

Disadvantages: Consumes greater amount energy (Fan BHP). Increases static pressure resulting in reduced air flow (CFM) with

existing equipment.


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Package Spacing

Package Rows should have a minimum of 2.00inch space between rows for air flow.


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Advantagesof Pallet Hardener

More mechanical simplicity than all other air

convection hardeners

Low capital investment Hardens multiple package sizes

Low maintenance costs


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Disadvantagesof Pallet Hardener

Mediocre to poor hardening results

Requires conscientious operator to insureproduct quality

High labor costs

High product shrinkage

Can result in unattractive packaging


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Advantagesof Spiral BeltHardener

Highest degree of mechanical simplicity of automated air

convection hardeners

Good hardening when operated within designparameters

Low to moderate capital investment

Hardens multiple package sizes simultaneously

Low production shrinkage through hardening process Available in system sizes from 250 GPH


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Disadvantagesof Spiral BeltHardener

Belt loading limited to 10 lbs/ft of belt for good

belt life

High fan horsepower results in high energydemands and cost

Requires low refrigerant temperatures

Very difficult to automate package handling inhigh output plants

High maintenance costs (belt cost represents

35% of typical system cost)


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Advantagesof Tray betweenContinuous Chain

Highest degree of mechanical simplicity of automatedtray type air convection hardeners

Double pass air system insures very good hardening

Moderate capital investment


Low production shrinkage through hardening process

Very good package orientation adapts to automation

Efficient air system reduces energy requirement and cost

Available in systems as small as 250 GPH


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Disadvantagesof Tray between

Continuous Chain

Feed rates less than 2500 GPH

Not very suitable for simultaneous multiple lineproductions

Higher maintenance costs than tray/transport

type systems


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AdvantagesofVariable Retention Time (VRT)

Hardener

Allows variable retention time for different sizeitems

Easily adapts to line automation

Maintains package orientation through the

hardening process Hardens multiple package sizes simultaneously

Handles high production rates (up to 10,000GPH)


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DisadvantagesofVariable Retention Time (VRT) Hardener

Highest cost hardener

Complex program and operation

Higher product shrinkage through system

High static pressures require higher HP and

energy requirements & longer retention times

Inherent design results in higher maintenancecosts

Minimum size system is approx 1500 GPH


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Multiple Tray Transport

H f h M l i l T


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Heart of the Multiple TrayTransport

2

3

4

5

1

The Transport

Ad


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AdvantagesofMultiple Tray Transport

Double pass air system insures very good hardening


Very low production shrinkage through hardening

process w/ good design Moderate mechanical simplicity of automated tray type

air convection hardeners

Moderate capital investment

Very low maintenance cost with long service life (40 +years)

Very good package orientation adapts to automation

Efficient air system reduces energy requirement and cost

Available in sizes to 10,000 GPH


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DisadvantagesofMultiple Tray Transport

No multiple retention time in standard form

Minimum size system is 750 GPH

More complex than spiral belt system

Higher product shrinkage w/ poor design


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Ad t


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AdvantagesofFusion Cell

Combination conduction/convection system hardens

faster than any air convection system Most efficient air hardening system -- rivals that of plate

hardener Hardens multiple package sizes simultaneously Very low production shrinkage through hardening

process Moderate mechanical simplicity of automated tray type

air convection hardeners Overall capital investment lower than most air systems Very low maintenance cost with long service life (30 +

years) Very good package orientation adapts to automation Available in sizes to 10,000 GPH Most compact of air convection hardeners Allows same refrigerant suction temp for both freezer and

hardener


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DisadvantagesofFusion Cell

No multiple retention time in standard form

Minimum size system is 750 GPH More complex than spiral belt system

Higher floor loadings than other air convection

types


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Manual Hardener DesignFan Coil

Air Plenum

Carts or Wire Basketsw/ Rows of Ice Cream Paks

= Laminar Flow

E C ti i A I


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Energy Consumption in Average Ice

Cream Plant

Mix Processing = 5 %

Freezing = 35%

Hardening = 45%

Storage = 15%

Total = 100%


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Real Energy Costs

1.0 HP motor w/ 16 Hr on/8 Hr off Cycle

8 Hr off = .746 x .08 x 8 Hr x 250 da

= $ 119.36

115 off day = .746 x .08 x 24 Hr x 115 da

= $ 164.72

Total Annual Energy Waste = $ 284.08

Total Waste for 25 Motors =$ 7,102.00 Does not include: refrigeration losses


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Individual Cartonvs

Over Wrapped

Package


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TRI-Tray Hardening Test w/ Individual Sqround

Retention Time: 2 Hr. 13 Min.

TRI-Tray Hardening Test w/ (6) Overwrapped Sqrds


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TRI-Tray Hardening Test w/ (6) Overwrapped Sqrds

Retention Time: 4 Hr. 33 Min.


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Design Objectives of Fast Hardener

Rapid hardening to achieve uniform ice crystallization

and improve quality.

Improve package quality.

Ability to adapt to future packaging/marketing changes.

Lowest possible product shrinkage thru hardeningprocess.

Low energy demand.

Low power (kwh) requirement.

Low direct labor. Low maintenance cost.

Adaptability to Automation.

Capital cost commensurate with operational savings.


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Any Question?

Thank You!

If you have any future question, please

contact: [email protected]

hardening and storage lecture2009

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