Energy Reduction through Induction Heating in Polymer Processing

1

• Energy Reduction through Induction Heating in
  Polymer Processing
• Presented by Neil Cooper
• 25 September 2008

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Operating Principle
Most steels heat up when exposed to a
high-frequency magnetic field
An induction heating system is made up of an
induction power supply and an induction coil. The
power supply sends alternating current through
the coil, generating an alternating magnetic
field. The alternating magnetic field induces
electrical eddy currents in the steel that
generate heat. The energy is transferred into the
steel as heat without physical contact.
Magnetic Field
Induction Coil
Induction Power Supply
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Operating Principle
Induction heating transfers energy directly into
the steel
Induction energy is generated directly in the
barrel to heat it from within Band-heaters only
heat from the outside and then the heat has to
transfer through the barrel to reach the resin
Barrel with Induction Heating
with Band-heaters
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Operating Principle
Patents Pending
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System Description
Complete nXheatTM System
nXheatTM Induction Coil Cable (supplied with
soldered lugs, and snap-together connector bodies)
nXheatTM Barrel Insulating Layer
Barrel
nXheatTM Wire-way
nXheatTM Power Modules
24 VDC on/off Control Signals (from machines
temperature controllers)
nXheatTM Extension Cables (connectorized both
ends)
220 VAC 3-phase to 8kW 220 VAC 1-phase to 4.5
kW 50/60 Hz
Patents Pending
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System Description
State of the Art nXheatTM Induction Power Module

• Up to 8 KW Output
• (4.5 kW with 220 single-phase)
• High-efficiency AC induction ( 95 efficient vs.
  30-70 for band-heaters)
• Ideal frequency range (15-25 kHz) for optimal
  heat penetration and temperature uniformity
• CE certified
• Interfaces to new or existing machine controls
  just like a band-heater (24 VDC input turns power
  on and off)

Note dimensions are overall, including feet,
handles, connectors, etc.
Patents Pending
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Installation
Easy Installation
Coil cables are supplied cut to length, fitted
with connectors and then wrapped around the
insulation at the pitch noted in the User Manual
Insulating sheets are supplied cut to size and
then are just wrapped around the barrel
(typically 4 times)
Patents Pending
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Energy Profile
Band-heaters
Process heat absorption 5 kW Heat loss to
machine 1 kW Heat loss from barrel surface
4 kW Heat generation from process (shear) 4
kW Heat input from heaters 6 kW

• Typical energy balance with band-heaters

Heater Power Output
4.2 kW (70)
0.6 kW (10)
1.2 kW (20)
Patents Pending
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Energy Savings
nXheatTM induction coil
2 kW versus 6 kW 67 reduction
Process heat absorption 5 kW Heat loss to
machine 1 kW Heat loss from barrel surface
0 kW Heat generation from process 4 kW Heat
input from heaters 2 kW

• Typical energy balance with nXheatTM

Heater Power Output
0.2 kW (10)
0.4 kW (20)
1.4 kW (70)
Zone 1
Zone 2
Zone 3
Patents Pending
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Energy Savings
Results Energy Savings (Barrel
Heating) (tonnages from 85 to 1350, processing
various resins)
Patents Pending
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Product Description
Easy Installation optional configurations
Full nXheatTM full benefit
Conventional Thermocouples
nXheatTM zone
Band-heaters
nXheat-HybridTM (40-70 of benefits)
Band-heaters
Patents Pending
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Start up Time
Faster Heat-up
Performance on 550 ton machine with 60 mm screw,
150 mm OD barrel and 5.2 kW nXheatTM power per
zone.
Even with conventional slow PID control nXheatTM
provides significantly faster heat-up. Existing
controls can be re-turned and new ones optimized
to provide even faster response.
Patents Pending
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Control Benefits
More responsive, balanced, repeatable temperature
control
Performance on 1000 ton machine with 90 mm screw,
210 mm OD barrel and 8 kW nXheatTM power per
zone. Temperature target dropped 7oC then raised
7oC
Cooling and heating responses are fast, balanced,
and repeatable
Patents Pending
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Control Benefits
Range Response Comparison (at same power
consumption)

• nXheatTM maximizes heat input and responds
  instantly
• Band-heaters waste heat and respond slowly

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Power is turned ON Power is turned OFF
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Ceramic Efficiency Loss
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MICA Efficiency Loss
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2
Even after power is turned off it takes minutes
before band-heaters stop heating the barrel
(because they retain heat)
Barrel is being heated
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nXheatTM
Barrel is losing heat to surrounding environment
1
MICA Band-heaters
Ceramic Band-heaters
1
Patents Pending
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Concentric Heating
Heat rises and collects under covers that are
needed for safety
Electrically-insulated induction coil
Thermal insulation
Band-heaters heat more where there are no
terminals, latches or hinges. This often results
in temperature variations around the barrel of
/- 5 (i.e. /-15oC at 300oC)
nXheatTM heats uniformly around the barrel and
eliminates unwanted external influences
Patents Pending
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Temperature Uniformity
Actual example of non-uniform band-heater
temperatures
Compare to cool and uniform temperatures with
nXheatTM
Patents Pending
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Processing Benefits
Patents Pending
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Shot Uniformity
Tighter control and better mixing improves
shot-to-shot uniformity
69 reduction in part weight variability (120
gram part on 550 ton machine)
Patents Pending
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Designed for Safety

• OD cool to the touch
• Safe electrical connections
• Teflon jacketed coil cable
• Entire system is CE certified
• Approved insulation sheet

High-temperature sheet insulation
Patents Pending
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Benefits Summary

• Reduce energy costs
• (barrel heating air-conditioning peak demand)

• Reduce energy costs
• (barrel heating air-conditioning peak demand)

• Reduce energy costs
• (barrel heating air-conditioning peak demand)

• Reduce energy costs
• (barrel heating air-conditioning peak demand)

• Reduce energy costs
• (barrel heating air-conditioning peak demand)

Patents Pending
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Benefits Summary

• Reduce energy costs
• (barrel heating air-conditioning peak demand)

• Reduce start-up time

• Increase throughput

• Improve quality

• Reduce scrap

• Reduce material use

• Reduce plant infrastructure costs
• (A/C equipment, power delivery systems)

Patents Pending
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• Energy Reduction through Induction Heating in
  Polymer Processing
• Presented by Neil Cooper
• 25 September 2008