Watlow Flexible Shapes and Geometries Application Guide

W A T L O W

Flexible Heaters

Flexible Shapes
and Geometries

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, without sacrificing
efficiency or dependability. With
Watlow’s customization capabilities,
you have the maximum amount of
freedom when designing your
equipment.

Excellent heat transfer results from
the heater’s thin design and its
direct bonding to the application.
Flexible heaters also provide fast
heatup and cool down rates,
uniform heat distribution and high
watt densities.

Features and Benefits

• Flat geometry permits holes,
notches and unusual shapes.

• Four material types and two
element styles are available for
wider flexibility in meeting your
requirements. See next page for
performance capabilities.

• Lightweight construction and
low thermal mass permit use in
applications that have limited
space or weight requirements.

• Heating elements as close as

0.003 inches (0.08 mm) from the
heated part respond to controls
with faster heat up and cool down.

• Uniformly spaced element
paths, placed within
(6 mm) of the heater perimeter,
distribute heat more evenly.

1

⁄4 inch

Wire-Wound
Element

• Same day shipment on stock units with orders
received by 11:00 a.m.CST.

Top Layer of Insulation
Sheath Material

Bottom Layer of Insulation
Sheath Material

Flexible Heaters

Etched Foil
Element

Applications

• Medical equipment such as blood
analyzers, respiratory therapy
units and hydrotherapy baths

• Satellite and communication
equipment

• Freeze protection for military
hardware, aircraft instrumentation,
hydraulic equipment, etc.

• Battery heating

• Semiconductor equipment

• Foodservice equipment

• Any application requiring a flexible
shape or design

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Flexible Heaters

Flexible Shapes
and Geometries

Applications and
Technical Data

Four Material Types

Silicone Rubber:

This rugged, moisture- and chemical­resistant material is easily bonded or
cemented to parts. Watlow silicone
rubber heaters can handle tempera­tures up to 500°F (260°C). Many
styles of these heaters are available
with UR®, cUR®and VDE
recognition. See page 171 for details.

Kapton®:

A thin, lightweight transparent
material from du Pont, Kapton®is
designed for extremely precise
heating requirements ranging from

-319° to 392°F (-195° to 200°C). It is
ideal for applications requiring low
outgassing in a vacuum, or
resistance to radiation, fungus and
chemicals. Many custom heaters can
be UR®and cUR®recognized.

Neoprene:

Neoprene resists weathering,
abrasion and chemicals. It can be
used economically in applications to
250°F (120°C), where high watt
densities are not needed.

HT Foil:

This mica-insulated, high
temperature foil is a semi-rigid
heater. Operating temperatures up to
1100°F (595°C) can be achieved.

See pages 169 to 182 and
189 to 194 for information
on silicone rubber,
Kapton®, neoprene, and
HT foil heaters.

Two Element Types

Watlow offers both wire-wound and
etched foil resistance elements.
These element types are available in

Wire-Wound Elements

Available on silicone rubber and
neoprene heaters, this element
style is created by spiraling fine
resistance wires around a fiberglass
cord. The element is then laid out in
a pattern designed specifically for
your application. The benefits of
wire-wound elements include:

• Excellent physical strength and
flexibility; repeated flexing of the
heater has no harmful effects on
its performance

• Good economy for small
production runs

• Conforms readily to curved
surfaces, including small
radius bends

Drum heaters and conduit bender
heaters are typical examples of
applications that use the wire­wound method. These heaters are
flexed repeatedly during use, but
due to their wiring, no internal
damage will occur.

most insulating materials, and
Watlow can recommend the type
best suited to your application.

Etched Foil Elements

This element type, created by acid
etching a circuit in nickel resistance
alloy foil, is available in silicone
rubber, Kapton
types. The etched foil element is
noted for its excellent circuit pattern
repeatability and superior heat
transfer, which results from greater
area coverage of the element. Other
benefits include:

• Delivers more heat and up to
twice the watt density of a wire­wound element, providing longer
heater life

• Most economical for large
production runs

• Complex heat distribution
patterns can be provided

The etched foil element style is
usually recommended for
applications requiring high
temperatures or watt densities, or
multiple zoning.

®

and HT foil heater

Kapton®is a registered trademark of
E.I. du Pont de Nemours & Company.

®

and cUR®are registered trademarks of

UR
Underwriter's Laboratories, Inc.

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