©2010 Glenro, Inc. Wire Expo 2010 Milwaukee 1

Effective Use of Infrared Heating

for

Wire & Cable Applications

Presentation Overview

• How it works– Effective Use of Infrared Theory

• What makes it work– Effective Equipment Choices

• Where it works– Effective Heating Solutions

©2010 Glenro, Inc. Presentation Overview 2

What is Infrared Energy?

• All objects above absolute zero (- 460° F) emit infrared radiation. The infrared portion of the electromagnetic spectrum is found between visible light and short radio waves. Infrared radiation is emitted at wavelengths between 0.72 and 1000 microns. However, only the 1 – 10 micron wavelength band is utilized in the vast majority of industrial heating applications (1% of the range).

• Figure 1: Useful Infrared Spectrum for Industrial Heating Applications

©2010 Glenro, Inc. Infrared Spectrum 3

Electromagnetic Spectrum - Useful Infrared Region

0.72 - 1 .5 µm 1.5 - 5.6 µm 5.6 - 10 µm

Short Wave Medium Wave Long Wave

©2010 Glenro, Inc. Infrared Heat Transfer 4

Infrared Radiation Heat Transfer

• Absorbed by the product• Transmitted through the product• Reflected away from the product

Useful Equation

• Wein’s Displacement Law: µm = C/T•  

– µm = Wavelength of most energetic radiation– T = Absolute Source Temperature– C = 5200 when applied to absolute temperature in Fahrenheit (°F + 460)– C = 2900 when applied to absolute temperature in Centigrade (°C = 273)

• This equation will calculate the most energetic or peak operating wavelength of the radiant source when operated at a specific temperature.

• If source temperature = 1500 °F, then µm = 5200/(460 + 1500) = 2.7

©2010 Glenro, Inc. Useful Equations 5

One Last Equation• Stefan-Boltzmann Law: W = Eσ (Ts

4 - Tt4)

– E = Emissivity Factor (1 for Black Body)

– Ts = Absolute Temperature of Source

– Tt = Absolute Temperature of Target

– σ = Stefan – Boltzmann Constant = 3.5 x 10-12 (° F + 460)4

– W = Watts/in2 Energy Density or Flux Transferred

• This equation shows how small changes in source temperature relate to much larger increases in energy transferred. The implication of this Law reveals that a practical limit is quickly reached with respect to industrial heating applications for the kinds of products and materials under consideration for this presentation.

 • As an example, if the source temperature is increased 10% from

1500° F to 1650° F, the energy transferred or flux increases from 51 W/in2 to 69 W/in2 or 35%.

. ©2010 Glenro, Inc

Useful Equations 6

©2010 Glenro, Inc. Wavelength vs Temperature 7

Understanding Target Absorption

• 2.9 µm or 1300° F– One place to run

• 6.0 µm or 400° F– Another place to run

• Target Temp = 250° F

• Using Stefan-Boltzmann– 2.9 µm ~ 32

Watts/in2

– 6.0 µm ~ 2 Watts/in2

Practical Overview of Theory• What you should know…

– Infrared energy delivered to a product by an industrial heater encompasses a range of wavelengths and temperatures

– The physical characteristics of your product will determine the rate at which infrared energy is effectively absorbed.

– Almost all products are highly absorptive at more than one wavelength.

• The Right Approach – Solve for Watt Density & Dwell Time– The key to successfully incorporating infrared energy on a product

manufacturing line relates more to watt density and dwell time and less to whether the infrared heater is operating at the peak absorption wavelength of the product.

– How aggressively can I heat my product before something bad happens? – How much time is required to transfer the energy I need to get my work done?

– These are the questions to answer that will serve you well and ultimately help you produce an acceptable product.

©2010 Glenro, Inc. Practical Overview of Theory 8

What Makes it Work

• Infrared Heater Characteristics

©2010 Glenro, Inc. Infrared Heater Characteristics

9

Characteristic Short Wave Medium to Long WaveQuartz Lamp (T-3) Quartz Cylinder Flat Panel

Radiant Effi ciency High to Medium High High to MediumMechanical Strength Low High MediumHeat Up/Cool Down Fast Slow Medium

Emitter Temperature 4000° F 1500° F 1800° FColor Sensitivity High Low Low

Wavelength Range 1 to 1.5 µm 2.5 to 5 µm 2.3 to 5 µm

Power Density 100 W/linear inch 10 W/in2 30 W/in2

Infrared Heater Illustrations

©2010 Glenro, Inc. Short Wave Infrared Heater 10

• High Watt Density• Quartz Lamp Emitters with Reflectors• Fast Response• Horizontal or Vertical• Water or Air Cooling Required• Single Pass• Product Centerline Crucial

Short Wave Infrared Heater

Infrared Heater Illustrations

©2010 Glenro, Inc. Medium to Long Wave Infrared Heater

11

• Low Watt Density• Resistive Wire Element Emitter • Quartz Core• Slow Response• Horizontal or Vertical• Solid Core/Split Case/Slotted Opening• Insulated Construction• Single Pass Typical• Rugged

Medium Wave Quartz Cylinder Radround® Heater

Infrared Heater Illustrations

©2010 Glenro, Inc. Medium to Long Wave Infrared Heater 12

• Medium Watt Density• Open Resistive Wire Element Construction• Medium Response• Horizontal or Vertical• Insulated Construction• Single or Multiple Pass Capable

Medium Wave Radplane® Heater

Controlling Technologies

• Open Loop Control • Semi-Open Loop

Control• Closed Loop Control

©2010 Glenro, Inc. Controlling Technologies 13

One of IR heating’s biggest advantages over other methods of heat transfer is its’ ability to transfer significant heat energy in a relative small space. This concentrated energy needs to be controlled accurately for repeatable process results. A radiant heater realizes its full potential for a given application only when the proper controls are utilized. The method of control relates the heater to the application.

Open Loop Control

• Open Loop Control: These circuits do not use heater or work (product) temperature as a control factor. Instead, control is by manually varying the heater supply voltage. Since there is no corrective feedback from heater temperature or work temperature, open loop control cannot be used where close control of the process is important.

• Heater Element vs Product Temperature Control :Where either the temperature of the heater or of the work (product) must be the controlling factor, a temperature sensing device must be used. To control by heater temperature, an embedded thermocouple is mounted in a fixed position relative to the heating element. To control by work (product) temperature, a radiation pyrometer or optical pyrometer is used. Each of these devices can be connected in a control loop.

©2010 Glenro, Inc. Open Loop Control 14

Semi-Open Loop Control

©2010 Glenro, Inc. Semi-Open Loop Control 15

Closed Loop Control

©2010 Glenro, Inc. Closed Loop Control 16

Response Time: Heater response is critical to making closed loop feedback control work.

Where it Works

• Preheat– PVC and steel conduit before

cutting– Wire prior to extrusion– Conductor with insulating tape

prior to jacket extrusion

• Heat– FEP extrusion on wire– Heat-Shrink tubing made of

Teflon on catheters– Heat-Shrink tubing– Singe and Heat-Clean fiberglass

sleeving prior to coating– Gel & Fuse PVC coatings on

fiberglass sleeving

• Cure– Extruded PVC and silicone

tubing/jackets

• Sinter– Extruded tubing made of Teflon® – PTFE cable wrap on multiconductor wire– Fluoropolymer resins on high

temperature wire 

©2010 Glenro, Inc. Applications 17

Where it Works

©2010 Glenro, Inc. Applications 18

• Dry– Dry and Cure striping and nomenclature ink on insulated wire– Dry and Cure color coding inks on fiber optics– Dry and Cure saturants (latex, acrylic, urethane) on fiberglass

sleeving (dielectric sleeving)– Water-based UV curable coatings on fiberglass sleeving prior to UV

cure– Lacquer or resin on braided magnetic wire– Graphite coatings on spark plug wire– Dry and Sinter PTFE dispersion coatings on glass braided tubing

made of Teflon (automotive fuel lines)– Extruded water-based adhesive on multiple wire ends– Residual moisture prior to outer jacket extrusion

Evaluating Applications

• What anyone needs to know…– Process Objective (preheat/predry/dry/heat/cure/sinter) – Product Weight (per linear foot)– Product Composition (materials of construction)– Process Line Speed– Target Entering Temperature– Target Exiting Temperature– Available Space (up/down/all-around)– Access/Threading/Maintenance– Operating Voltage

©2010 Glenro, Inc. Evaluating Applications 19

System Illustrations

• Heat Source: Solid Radround®

• Heated Length: 42”• Features:

– Support Frame– End Closures– Integral Semi-Open Loop

Temperature Control System

©2010 Glenro, Inc. System Illustrations 20

Preheat Fine Gauge & Braided Wire prior to Teflon® Extrusion

System Illustrations

• Heat Source: Split-case Radround®

• Heated Length: 126”• Features:

– Support Frame– Auto-Retraction– Semi-Open Loop

Temperature Control System

©2010 Glenro, Inc. System Illustrations 21

Dry PTFE Release Agent on Bare Stranded Tin/Copper Wire in line with Extruder

System Illustrations

• Heat Source: Short Wave Infrared Heater

• Heated Length: 76”• Features:

– Support Frame– Capstan Wheel– Integral Open Loop Control

System

©2010 Glenro, Inc. System Illustrations 22

Cure Extruded Tubing or Jacket on Wire/Cable

System Illustrations

• Heat Source: Split-case Radround®

• Heated Length: 84”• Features:

– Support Frame– End Closures/Product

Support– Automated Dual Retraction– Portable– Integral Semi-Open Loop

Temperature Control System

©2010 Glenro, Inc. System Illustrations 23

Cure Solvent Based Resin Impregnated Braid on Copper (Magnetic) Wire 

System Illustrations

• Heat Source: Open Element Hi-Temp Heat Tunnel

• Heated Length: 126”

©2010 Glenro, Inc. System Illustrations 24

Vertical Multiple-end or Multi-pass Medium Wave Infrared System

System Illustrations

• Heat Source: Open Element Hi-Temp Heat Tunnel

• Heated Length: 42”

©2010 Glenro, Inc. System Illustrations 25

Horizontal Multiple-end or Multi-pass Medium Wave Infrared System

©2010 Glenro, Inc. Conclusions 26

Conclusions

• Infrared is a viable industrial heating solution for many wire and cable applications, if properly designed and controlled

• Don’t get too caught up in the theory of it all – it is easy to test run the technology to determine viability, both technically and economically

• Typical returns on the investment are attractive and periods short if the installation results in increased product revenue streams

• Most equipment solutions for wire and cable applications are electrically heated, thus, you are not adding to an existing carbon footprint

• Go to www.glenro.com to learn more, sign up for our newsletters or to contact us