Watlow Ceramic Fiber Heater Specifications

Ceramic Fiber Heaters

®

Heated Insulation
Package

Ceramic fiber heaters offer some of the highest temperature
heating element capabilities in the Watlow

®

family of heaters.
Heating units constructed with ceramic fiber insulation isolate
the heating chamber from the outside. Ceramic fiber heaters
are extremely low mass, high insulation value units with
self-supported heating elements. Many applications benefit
from the convenience of the heating element and insulation
combined into one package. Lightweight, low-density
properties make Watlow’s ceramic fiber heaters ideal for
high-temperature applications requiring low thermal mass.

Features and Benefits

High temperature ICA resistance elements

• Bounds integrally into required position

• Allows five element configurations

Lightweight, low-density alumina-silica composition
molded into shape

• Acts as an insulation to isolate the heating chamber from

the outside

• Provides low shrinkage fiber and inorganic binder

• Assures a firm, thermal shock resistant, self-supporting

unit at all operating temperatures

Operating temperatures up to 2200°F (1204°C)

• Provides high temperature performance that cannot be

achieved with many other heater types

Low mass ceramic fiber insulation of 10 to 15 lb/ft
(160 to 240 kg/m3)

• Allows the heater to reach process temperature quickly

• Enables the energy to heat the load instead of wasting

energy on itself

Works directly off common power line voltages

• Eliminates the need for expensive transformers or

complex power control systems

• Enables compatibility with the full range of Watlow

temperature controllers and power switching devices

3

High
Temperature
ICA Heating
Element

Lightweight
Alumina­Silica Fiber
Composition

Ductile Alloy

Additional
Coating for
Added Strength
and Surface
Hardness

Thin, Tough, High Temperature Ceramic
Coating over Embedded Elements, plus
Optional High Emissivity Coating

Strip Leads

Performance Capabilities

• Operates at temperatures up to 2200°F (1204°C)

2

• Allows watt densities from 5 to 30 W/in

(0.8 to 4.6 W/cm2)

• Uses “radiant” heat transfer exclusively

Typical Applications

• High temperature furnaces

• Metal melting, holding and transfer

• Semiconductor processing

• Glass, ceramic and wire processing

• Analytical instrumentation

©2001, 2011 Watlow Electric Manufacturing Company, all rights reserved.

COL-CFH-0311

Options

Embedded Sinuated Elements

Exposed Sinuated Elements

Flat Sinuated

V-Sinuated

• Available in either flat or V-sinuated element configurations

• An advanced V-sinuated element configuration allows up

to 27 percent additional watt density over embedded flat
sinuated elements

• Performs best at medium to high temperatures at medium

watt density power requirements

• Use in partially enclosed to fully enclosed applications

• Especially suited for large, flat units; semi-cylindrical units

above 5 in. (125 mm) inside diameter; and full cylinders
above 4 in. (100 mm) inside diameter.

• Offers greater effective insulation thickness than coiled

element designs

• Enhances “heated insulation” concept of operational use

• Features high emissivity coating on new high-watt density

series units.

Flat Sinuated

V-Sinuated

•

Available in either flat or V-sinuated element configurations

• Advanced V-sinuated element configuration allows up to

20 percent additional watt density over that of exposed
flat sinuated elements

• Offers the lowest possible wire-to-chamber temperature

difference for maximum heater life

• Provides optimum heat-up/cool-down and recovery times

as well as maximum efficiency of operation

• Higher current handling capabilities possible

• Minimizes the number of circuits and connections in large

furnaces

• Especially well suited for large, flat surface area units and

large inside diameter curved units

• Exposed elements are available on special order as a

variation of the embedded sinuated element normally
provided on stock and standard units.

Style A Lead

(Type 1 or 2 Unit)

Style A

(Type 3 or 4)

Pocket

Cold
Face

Stub

Strip Lead
(add-on)

Vestibule

Style B Lead

(Type 1 or 2)

Style B

(Type 3 or 4)

Style A Lead (Type 5)

Style B (Type 5)

Style A (Type 6)

Style B (Type 6)

Style C (Type 6)

Style A (Type 8)

Style B (Type 8)

Style C (Type 8)

Style C (Type 5)

Pocket

Cold
Face

Stub

Strip Lead
(add-on)

Length

Width

Flexible

Stranded

MGT Insulated

Nickel Lead Wire

(450°C Rated)

Solid NiCr

Wire

Stub on
Heater
in Pocket
(Typ.)

Termination Options

Watlow offers variations of electric leads to meet particular
wiring requirements. To understand the termination options
available, it is necessary to understand the different ways
electrical leads can be applied.

Ceramic fiber heater electrical leads are welded to stubs –
the metal parts that interface between the heating element
wire and the add-on electrical leads. These stubs exit the
heater at the lead pockets. Pockets are small cavities, below
the cold face plane (outside surface) and generally located at
or near the corners.

Watlow ceramic fiber heaters are equipped with either strip
leads or double twisted wire leads. Strip leads are most
commonly used, unless otherwise specified. The various
lead styles refer to the lead’s exit orientation relative to the
pocket used on a given type of heater.

Strip Leads

Flat and semi-cylindrical ceramic fiber heaters are available
with the termination options shown. When ordering
termination options for catalog units, the specific strip lead
Style must be specified. To determine the desired style, refer
to the illustrations shown on this page. Otherwise, Style A
leads will be provided and the length will be 12 in. (305 mm).
Additional lengths are possible using add-on leads, which
are priced per pair, per inch, for the three different widths.
See the ordering charts for data on which lead width is used
on a specific heater.

Strip leads are shipped with a
of the lead. Use #10-24 screws, nuts and washers, or other
wiring connections. Caution should be exercised when
making connections. Leads are susceptible to loosening due
to thermal expansion and contraction as the heater cycles.

Special Lead Orientation

If the various standard strip lead orientations and pocket
configurations are not suitable, special designs are possible.

Leads Bent 90 Degrees

The double twisted leads of full cylinder heaters can be bent
90 degrees to lay into slots and exit to the sides of the unit.

Special Add-On Lead Configurations

The two options illustrated can be welded onto the stub at
the heater pocket, or for a better installation, welded on at
the end of a specified length of the regular strip lead. The
strip lead length can vary from zero to the value necessary to
get away from the hot zone. The length of the add-on lead
option eliminates the need for a custom product and
satisfies a greater range of wiring requirements.

13

⁄64 in. (5 mm) hole at the end

Flat Units

Semi-Cylindrical Units

Accessories.

Inside

Outside

Metal Wall
or Shroud

Overall O.D. Head

Overall
Length

Shank

Int.

Ext.

Wire Dia.

Double Twisted

and Flexible Leads

Strip Leads

Ceramic fiber heater orders can also include the following
accessory items.

Rigidizer

Rigidizer is primarily used to recoat soft, cut edges of
ceramic fiber heaters and ceramic fiber insulation panels.
Various degrees of hardening can be achieved with additional
applications.

B.T.E. Closed-End Thermocouple Tubes

Horizontal thermocouple tube between the elements. Two
sizes are available: 0.140 in. (3.6 mm) and 0.265 in. (6.7 mm),
both 6 in. (152 mm) long with closed end.

Black Surface Coat

Black high emissivity coating is used to raise emissivity
closer to 1.0.

Ceramic Tubes

Ceramic tubes are available in four nominal sizes:
and1⁄2 in. (3.2, 6, 9.5 and 13 mm) inside diameter and lengths
of 0.9 in. (22 mm) and 1.9 in. (48 mm) long. Ceramic tubes
have several uses, including thermocouple mounting holes,
mounting pin sleeves and lead coverings.

Dry Heating Surface Mix

Dry heating surface mix is used to make the hot face of all
heaters, including those with the high emissivity coating. It
can also be used with rigidizer to make a very high
temperature paste for touch ups of the hot face area.

Patch Kit

To easily repair small breaks or cracks, the patch kit contains
one pint (0.47 L) of powered ceramic fiber, four ounces (0.118 L)
of black surface coat. Order CFPATCHKIT.

Ceramic Fiber Insulation Blanket

Additional insulation value for ceramic fiber heaters is available
with a ceramic fiber insulation blanket. This 6 lb/ft
ceramic fiber blanket contains no organic binders. It is suitable
for applications up to 2300°F (1260°C) and is sold in full rolls or
cut by the square foot.

Powdered Ceramic Fiber

Powdered ceramic fiber is used primarily to improve surface
finish in critical areas. It can also be used to repair damaged
units by filling voids, cracks and broken corners. Use powdered
ceramic fiber with rigidizer to make an easily applied paste.

High Temperature Coating and Electrical Potting Cement

Two different high purity, high temperature cements have multiple
uses: mount thermocouple tubes, provide extra surface
hardening, bond ceramic fiber gaskets and affix lightweight
ceramic fiber insulation blanket to panels, as well as attach
edge-spacer blocks and custom vestibules.

1

⁄8,1⁄4,3⁄8

3

(96 kg/m3)

Strip Lead Porcelain Bushings

Strip lead porcelain bushings are primarily used to protect heater
power leads when passing through the metal walls and furnace
structures. Bushings are available for use with double twisted
leads and the three standard strip lead widths.

Watlow®is a registered trademark of Watlow Electric Manufacturing Company.

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