Transcript Ice Cream Hardening

Rapid Hardening Systems
By R.C.Greener
Which Would You Rather Buy?
A
or
B
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
Costs to Harden Rapidly
• More energy
• Higher Capital Investment
• Increased product shrinkage if design
improper
Percentage of H2O Frozen at
Various Draw/Fill Temperatures
Draw Temp
% H2O Frozen
+25oF
+24oF
+23oF
+22oF
+21oF
+20oF
-15oF
33.0
41.0
47.0
52.0
56.0
59.0
90.0
Two Types of Hardening
Open Loop
Closed Loop
Ice Cream Manufacturer
Purchases Refrigeration
Ice Cream Manufacturer
Refrigerates with
Self Contained System
Common
Hardening Methods
Cryogenic
Open Loop
Immersion
Plate
Air
Comb. Plate/
Convection Air Convection
Closed Loop
Advantages of
Cryogenic 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
Disadvantages of
Cryogenic 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
How Immersion & Plate Systems Harden
Ice Cream
Heat Transferred by
Direct Conduction from
Product to Refrigerant
Mechanical
Refrigeration
System
Evaporative
Condenser
Energy Transferred from
Refrigerant to Atmosphere
Advantages of
Immersion Hardening
• Best method to harden stick novelties
• Rapid hardening with resultant minimum
retention times
• Automation allows high production rates
• High product quality
• Efficient heat removal process
Disadvantages of
Immersion Hardening
•
•
•
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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 relatively
high
• High capital expense for single item
manufacture
Advantages of Plate Hardener
• Makes near perfect squares and rectangles on
95% of production
• Rapid hardening with resultant minimum
retention times
• Heat removal via conduction is very efficient
• Requires minimal space in low cost ambient
warehouse environment
• Low production shrinkage through hardening
process
Disadvantages of 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 moving
hollow plate
• Requires low refrigerant temperature
How Air Convection Hardens
Cold
Air
Ice Cream
Coil
Mechanical
Refrigeration
System
Evaporative
Condenser
Warm
Air
Conduction from
Product to Air
Conduction From
Product to Refrigerant
Conduction from
Refrigerant to
Atmosphere
Air Convection Significance
• Used for Hardening over 85% of Ice
Cream in US.
• Used by over 95% of Ice Cream
Manufacturers in US
Important Facts about
Convection Hardening
• Product Draw or Fill Temperature
• Package Orientation during Hardening
Process.
• Laminar Air Flow Vs. Turbulent air flow
• Air Vs. Heat Removal Index Temperature
• Product Spacing
Importance of
Draw/Fill Temperatures
Draw Temp
% H2O Frozen
+25oF
+24oF
+23oF
+22oF
+21oF
+20oF
-15oF
33.0
41.0
47.0
52.0
56.0
59.0
90.0
Air Flow Perpendicular to Pak
Length
• Package: 4 – 56 oz.
• Flavor: Choc. Peanut
butter 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
Air Flow Parallel to Pak Length
• Package: 4 – 56 oz.
• Flavor: Choc. Peanut
butter cup.
• Air Temp.:
-25o F
• Air Velocity: 1000 FPM
• Core Temp In: +19.8o F
• Core Temp Out: -1.3o F
• Retention Time =
4 Hr 18 Min
Draw Temp vs. Hardening Times
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Package: 4 – 56 oz. SqRd
Flavor: Pumpkin Crème
Air Temp.:
-23o F
Air Velocity: 1000 FPM
Core Temp In: +23.2o F
Core Temp Out: -0.1o F
• Retention Time =
5 Hr 28 Min
•
•
•
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•
Package: 4 – 56 oz. SqRd
Flavor: Pumpkin Crème
Air Temp.:
-23o F
Air Velocity: 1000 FPM
Core Temp In: +19.3o F
Core Temp Out: -0.2o F
• Retention Time =
4 Hr 4 Min
Laminar vs Turbulent Air Flow
Definitions:
Laminar Flow = Streamline flow in a viscous fluid near
a solid boundary.
Turbulent Flow = Fluid flow in which the velocity at a
given point varies erratically in magnitude and
direction.
The requirement for an efficient air distribution
system is
Conversion from Turbulent Flow
to
Laminar Flow
What Causes Turbulent Flow?
1.
2.
3.
Fans and other mechanical methods of moving air.
Obstructions to normal air flow.
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.
Package Spacing
Package Rows should have a minimum of 2.00
inch space between rows for air flow.
Advantages of Pallet Hardener
• More mechanical simplicity than all other air
convection hardeners
• Low capital investment
• Hardens multiple package sizes
• Low maintenance costs
Disadvantages of Pallet Hardener
• Mediocre to poor hardening results
• Requires conscientious operator to insure
product quality
• High labor costs
• High product shrinkage
• Can result in unattractive packaging
Advantages of Spiral Belt
Hardener
• Highest degree of mechanical simplicity of automated air
convection hardeners
• Good hardening when operated within design
parameters
• Low to moderate capital investment
• Hardens multiple package sizes simultaneously
• Low production shrinkage through hardening process
• Available in system sizes from 250 GPH
Disadvantages of Spiral Belt
Hardener
• Belt loading limited to 10 lbs/ft of belt for good
belt life
• High fan horsepower results in high energy
demands and cost
• Requires low refrigerant temperatures
• Very difficult to automate package handling in
high output plants
• High maintenance costs (belt cost represents
35% of typical system cost)
Advantages of Tray between
Continuous Chain
• Highest degree of mechanical simplicity of automated
tray type air convection hardeners
• Double pass air system insures very good hardening
• Moderate capital investment
• Hardens multiple package sizes simultaneously
• 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
Disadvantages of Tray between
Continuous Chain
• Feed rates less than 2500 GPH
• Not very suitable for simultaneous multiple line
productions
• Higher maintenance costs than tray/transport
type systems
Advantages of
Variable Retention Time (VRT)
Hardener
• Allows variable retention time for different size
items
• Easily adapts to line automation
• Maintains package orientation through the
hardening process
• Hardens multiple package sizes simultaneously
• Handles high production rates (up to 10,000
GPH)
Disadvantages of
Variable 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 maintenance
costs
• Minimum size system is approx 1500 GPH
Multiple Tray Transport
Heart of the Multiple Tray
Transport
5
4
3
2
1
The Transport
Advantages of
Multiple Tray Transport
• Double pass air system insures very good hardening
• Hardens multiple package sizes simultaneously
• 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
Disadvantages of
Multiple 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
Advantages of Fusion 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
Disadvantages of Fusion Cell
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•
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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
Manual Hardener Design
Fan Coil
Air Plenum
Carts or Wire Baskets
w/ Rows of Ice Cream Paks
= Laminar Flow
Energy Consumption in Average Ice
Cream Plant
• Mix Processing
=
5%
• Freezing
=
35%
• Hardening
=
45%
• Storage
=
15%
=
100%
Total
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
Individual Carton
vs
Over Wrapped
Package
TRI-Tray Hardening Test w/ Individual Sqround
Retention Time: 2 Hr. 13 Min.
TRI-Tray Hardening Test w/ (6) Overwrapped Sqrds
Retention Time:
4 Hr. 33 Min.
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 hardening
process.
• Low energy demand.
• Low power (kwh) requirement.
• Low direct labor.
• Low maintenance cost.
• Adaptability to Automation.
• Capital cost commensurate with operational savings.
Any Question?
Thank You!
If you have any future question, please
contact: [email protected]