Watlow FIREROD Application Guide
Electric Heaters
7
W A T L O W
Application Guide
Electric Heaters
Product Overview
This section of the Application Guide
is devoted to electric heaters; their
different types, methods of use and
general calculations for determining
specifications. If you’re unable to find
or determine which type of Watlow
heater will best suit your needs, call
your nearest Watlow sales representative. Sales offices are listed on the
back cover of this Application Guide.
Heaters
Band and Nozzle Heaters
Led by the high performance MI Band heater, the patented, flexible
THINBAND®heater and the standard mica band heater for specialized
constructions, Watlow’s band and nozzle heaters are ideal for every type of
plastic processing equipment.
Sheath materials available include stainless steel with mica insulation, stainless
steel with mineral insulation and aluminized or zinc steel with mica insulation.
Performance Capabilities
• Maximum operating temperatures
to 760°C (1400°F)
• Typical maximum watt densities from
8.5 W/cm2(55 W/in2) to
35.7 W/cm2(230 W/in2)
Applications
• Extruders
• Blown film dies
• Injection molding machines
• Other cylinder heating applications
Cable Heaters
The versatile Watlow cable heater can be formed to a variety of shapes as
dictated by its many applications. These small diameter, high performance units
are fully annealed and readily bent to your desired configuration.
Sheath materials available include Inconel®and stainless steel.
Performance Capabilities
• Typical maximum watt densities to
4.6 W/cm2(30 W/in2)
• Maximum operating temperatures
to 650°C (1200°F)
Applications
• Plastic injection molding nozzles
• Semiconductor manufacturing and
wafer processing
• Hot metal forming dies and punches
• Sealing and cutting bars
• Restaurant and food processing
equipment
• Cast-in heaters
• Laminating and printing presses
• Air heating
• Heating in a vacuum environment
• Textile manufacturing
Inconel®is a registered trademark of the
Special Metals Corporation.
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Application Guide
Electric Heaters
Product Overview
Continued
Cartridge Heaters
The Watlow FIREROD
®
heater enters its 50th year of industry leading expertise
as the premier choice in swaged cartridge heating. With premium materials
and tight manufacturing controls, the FIREROD heater continues to provide
superior heat transfer, uniform temperatures and resistance to oxidation and
corrosion in demanding applications and high temperatures.
Sheath materials available are Incoloy®and stainless steel.
Performance Capabilities
• Typical maximum watt densities up
to 62 W/cm2(400 W/in2)
• Maximum operating temperatures
to 760°C (1400°F)
Applications
• Molds • Life sciences
• Dies • Aerospace
• Platens • Semiconductor
• Hot plates • Foodservice
• Sealings
• Fluid heating
Cast-in Heaters
When Watlow creates a custom-engineered cast-in product, the result is more
than just a heater. It’s a “heated part” that becomes a functional component of
your equipment, designed in the exact shape and size you need. The IFC
heated part consists of a Watlow heater element built into custom metal shapes
designed specifically for your application.
Sheath materials available are 319 and 356 aluminum, pure aluminum and
IFC (stainless, nickel, Inconel®, aluminum, copper and bronze).
Performance Capabilities
• Typical maximum watt densities to
15.5 W/cm2(100 W/in2)
• Maximum operating temperatures
to 400°C (752°F) to 760°C (1400°F)
depending on material
Applications
• Semiconductor manufacturing
• Foodservice equipment
• Plastics processing
• Medical equipment
• Hot glue melt
• Circulation heating
Incoloy®and Inconel®are registered
trademarks of the Special Metals Corporation.
equipment
Electric Heaters
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W A T L O W
Application Guide
Electric Heaters
Product Overview
Continued
Circulation and Process Heaters
Watlow’s circulation heaters are compact heating solutions for fluids such as
purified and inert gases, supercritical fluids and liquids like de-ionized water
for use in semiconductor and electronics industries as well as for general liquid
and gas heating applications. Watlow’s industrial process heater lines of
immersion, circulation and duct heaters are used to heat a myriad of high and
low viscosity fluids ranging from de-ionized and process water, oils, solvents,
rinse agents, caustic solutions, etc. to process gases like air, nitrogen, purified
and inert gases as well.
Applications
• Oil and gas field equipment
• Refineries & petrochemical plants
• Chemical and industrial gas plants
• HVAC duct heating
• Open tanks and heat treat baths
• Textile drying
• Heat transfer and lube oil systems
• Semiconductor processing equipment
• Precision cleaning equipment
• Power generation systems
• Emissions control systems
• Supercritical fluid heating
• In-line water boilers
Ceramic Fiber Heaters
Ceramic fiber heaters integrate a high temperature iron-chrome-aluminum
(ICA) heating element wire with ceramic fiber insulation. Numerous stock,
standard and/or custom shapes can be provided, achieving the “heated
insulation” concept for your high temperature, non-contact applications. The
ceramic fiber insulation isolates the high temperatures inside the heated
chamber from the outside. The heaters are low mass, fast heating, with high
insulation values and the self-supported heating elements that offer some of
the highest temperature heating capabilities within the Watlow family of heater
designs.
The sheath material available is molded ceramic fiber.
Performance Capabilities
• Typical maximum watt densities to
1.8 W/cm
2
(11.5 W/in2)
• Maximum operating temperatures
to 1205°C (2200°F)
Applications
• High temperature furnaces
• Metal melting, holding and transfer
• Semiconductor processing
• Glass, ceramic and wire processing
• Analytical instrumentation
• Fluidized beds
• Laboratory and R&D
• Other high temperature process
applications
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Multicell Heaters
The multicell heater from Watlow offers independent zone control for precise
temperature uniformity, loose fit design for easy insertion in and removal from
the equipment and extreme process temperature capability. The heaters are
available with up to eight independently controllable zones and one to three
internal thermowells for removable sensors. Custom assemblies are available.
Incoloy®sheath material is available.
Performance Capabilities
• Typical maximum watt densities to
6.2 W/cm2(40 W/in2)
• Maximum operating temperatures
to 1230°C (2250°F)
Applications
• Super plastic forming and diffusion
bonding
• Hot forging dies
• Heated platens
• Furnace applications
• Superheating of air and other gases
• Fluidized beds for heat treating
• Glass forming, bending and tempering
• Long heater needs (1219 cm (40 foot))
• Soil remediation
• Aluminum processing
Application Guide
Electric Heaters
Product Overview
Continued
Flexible Heaters
Flexible heaters from Watlow are just what the name implies: thin, bendable and
shaped to fit your equipment. You can use your imagination to apply heat to the
most complex shapes and geometries conceivable without sacrificing efficiency
or dependability.
Sheath materials available include silicone rubber, Kapton®, HT foil and neoprene.
Performance Capabilities
• Typical maximum watt densities from
1.7 W/cm2(11 W/in2) to 17.0 W/cm
2
(110 W/in2)
• Maximum operating temperatures
to 595°C (1100°F)
Applications
• Medical equipment such as blood
analyzers, respiratory therapy units and
hydrotherapy baths
• Freeze protection for military hardware,
aircraft instrumentation and hydraulic
equipment
• Battery heating
• Foodservice equipment
• Factory bonding / subassemblies
• Any application requiring a flexible shape
or design
Kapton®is a registered trademark of
E.I. du Pont de Nemours & Company.
Electric Heaters
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W A T L O W
Application Guide
Electric Heaters
Product Overview
Continued
Radiant Heaters
With Watlow’s diverse RAYMAX
®
heater line, we have a solution for almost any
application requiring radiant heat. Our capabilities cover a wide range of
needs, from contamination-resistant panel heaters to fast-responding quartz
tubes to rugged tubular elements and high temperature ceramic panels.
Incoloy®tubular, molded ceramic fiber, quartz tube and stainless steel emitter
strip sheath materials are available.
Performance Capabilities
• Typical maximum watt densities from
4.6 W/cm2(30 W/in2) to 7.0 W/cm
2
(45 W/in2)
• Maximum operating temperatures to
1095°C (2000°F)
Applications
• Thermoforming
• Food warming
• Paint and epoxy curing
• Heat treating
• High temperature furnaces
• Tempering and annealing processes
Polymer Heaters
For the latest in heating technology from Watlow, specify a heated plastic part
in your next product. Watlow’s heated plastic parts combine resistive heating
elements with a wide range of thermoplastic compounds to yield a part that is
both heater and structure. Watlow utilizes typical injection molding techniques
and patented resistive element construction methods to produce heated plastic
parts that are durable, safe and cost-effective.
Performance Capabilities
• Typical maximum open watt densities
from 0.08 W/cm2(0.5 W/in2) to
0.59 W/cm2(3.8 W/in2)
• Typical maximum immersion watt
densities from 0.62 W/cm2(4.0 W/in2)
to 9.30 W/cm2(60 W/in2)
• Maximum operating temperatures to
220°C (428°F)
Applications
• Medical • Battery heating
• Analytical • Foodservice
• Aerospace • Transportation
• Freeze protection • Semiconductor
• Any heated part application requiring a
flexible shape
Alcryn®is a registered trademark of
Ferro Corporation.
Santoprene®is a registered trademark of
Advanced Elastomer Systems.
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Strip Heaters
Watlow’s mica and 375 strip heaters are the versatile solution for a number of
applications. They can be bolted or clamped to a solid surface for freeze and
moisture protection, food warming and other applications or utilized as a noncontact radiant heater. The 375 finned strip heaters are commonly used for air
heating, drying ovens and space heaters.
Performance Capabilities
• Typical maximum watt densities from
7.8 W/cm2(50 W/in2) to 15.5 W/cm
2
(100 W/in2)
• Maximum operating temperatures to
760°C (1400°F)
Applications
• Dies and molds
• Tank and platen heating
• Thermoforming
• Packaging and sealing equipment
• Ovens
• Food warming equipment
• Vulcanizing presses
• Duct, space and air heaters
• Incubators
• Autoclaves
• Freeze and moisture protection
Application Guide
Electric Heaters
Product Overview
Continued
Thick Film Heaters
Watlow layers thick film resistor and dielectric materials on quartz, stainless steel
and ceramic substrates to produce high performance industrial heaters. The
thick film heaters provide very fast temperature response and uniformity on a
low-profile heater. Thick film heaters are ideal for applications where space is
limited, where conventional heaters can’t be used, when heat output needs vary
across the surface, or in ultra-clean or aggressive chemical applications.
430 stainless steel (open air), 430 stainless
steel (immersion), aluminum nitride, quartz
(open air) and quartz (clamp-on) sheath
materials are available.
Performance Capabilities
• Typical maximum watt densities from
3 W/cm2(20 W/in2) to 27 W/cm
2
(175 W/in2)
• Maximum operating temperatures to
550°C (1022°F)
Applications
• Ultra pure aggressive chemicals
• Large panel processing
• Analytical equipment
• Foodservice equipment
• Packaging sealing equipment
• Life sciences sterilizers and GC/mass
spectroscopy
• Semiconductor wafer process equipment
• Plastics hot runners nozzles and
manifolds
Electric Heaters
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W A T L O W
Tubular and Process Assemblies
Watlow’s WATROD tubular heater elements and flat FIREBAR elements are
designed primarily for direct immersion in liquids such as water, oils, solvents
and process solutions, molten materials as well as air and gases. By generating
all the heat within the liquid or process, these heaters are virtually 100 percent
energy efficient. These versatile heaters can also be formed and shaped into
various geometries for radiant heating and contact surface heating applications.
UL®and CSA component recognized elements available.
Applications
• Furnaces and ovens
• Molten salt baths
• Foodservice equipment
• Semiconductor equipment
• Die casting equipment
• Metal melt and holding
• Fluidized beds
• Boilers
• Radiant heating
• Process air heating
• Drying and warming
Application Guide
Electric Heaters
Product Overview
Continued
14
Application Guide
Electric Heaters
Most electrical heating problems
can be readily solved by determining the heat required to do the job.
To do this, the heat requirement must
be converted to electrical power and
the most practical heater can then
be selected for the job. Whether the
problem is heating solids, liquids or
gases, the method, or approach, to
determining the power requirement
is the same. All heating problems
involve the following steps to their
solution:
Define the Heating Problem
Calculate Power Requirements
System Start-up and Operating Power
Requirement
System Maintenance Power
Requirements
Operating Heat Losses
Power Evaluation
Review System Application Factors
Safe/Permissible Watt Densities
Mechanical Considerations
Operating Environment Factors
Safety Factor
Heater Life Requirements
Electrical Lead Considerations
Defining the Problem
Your heating problem must be clearly stated, paying careful attention to
defining operating parameters. Gather
this application information:
• Minimum start and finish
temperatures expected
• Maximum flow rate of material(s)
being heated
• Required time for start-up heating
and process cycle times
• Weights and dimensions of both
heated material(s) and containing
vessel(s)
• Effects of insulation and its thermal
properties
• Electrical requirements—voltage
• Temperature sensing methods and
location(s)
• Temperature controller type
• Power controller type
• Electrical limitations
And since the thermal system you’re
designing may not take into account
all the possible or unforeseen heating
requirements, don’t forget a safety
factor. A safety factor increases
heater capacity beyond calculated
requirements. For details on safety
factor, please see “Safety Factor
Calculation” under the portion of this
section dealing with “Review of Heater
Application Factors,” on page 20.
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