Watlow FIREROD Data sheet

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Cartridge Heaters

FIREROD®Immersion

FIREROD®immersion heaters
package to 300 W/in2(46.5 W/cm2)
in a compact unit, giving you greater
versatility in designing your heating
system. This design solution is ideal
for replacing large screw-plug
immersion heaters.

Aside from its versatile design, these
heaters come complete with a brass

3

⁄4 inch NPT double threaded screw
plug, which allows you to add
conduit boxes. Also, FIREROD
immersion heaters are sealed at the
lead end with a silicone rubber seal.
Solid copper leads, with silicone
rubber sleeve, are provided for
unconfined wiring. These units are
recommended for immersion in
water or 90+ percent water soluble
solutions.

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• Maximum operating temperature

in water to 100°C (212°F) at
atmospheric pressure

• Maximum watt density to

300 W/in2 (46.5 W/cm2)

• Maximum voltage to 480VÅ(ac)

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• Nickel-chromium resistance

wire, precisely centered in the

unit, assures even, efficient
distribution of heat to the sheath.

• Magnesium oxide insulation,

compacted to the proper density,
results in high dielectric strength
and contributes to faster heat-up.

• Incoloy®sheath resists corrosion

from water.

• Metallurgically-bonded

conductor pins overlap the
resistance wire inside the core,
ensuring trouble-free electrical
continuity.

• Lead end with silicone rubber

seal protects the heater against
moisture contamination.

• Optional stainless steel fittings

are available for use in corrosive
applications.

Incoloy®is a registered trademark of
Special Metals Corporation.

s

s

4 in. (100 mm)

No-Heat

6 in. (150 mm) Solid
Pins with Silicone
Rubber Boots

• Horizontal through the wall tank
mounting makes set-up faster.

• 240 and 480VÅ(ac) give
flexibility in wiring the heater for
use in your particular application.

W

Same day shipment on all stock units.

•

Incoloy
Sheath

Nickel-Chromium
Resistance Wire

Magnesium
Oxide Insulation

Double Threaded Brass

3

⁄4 in. NPT-13⁄8 in. long (35 mm)

AApppplliiccaattiioonns

• Plastic reclamation

Food preparation

•

Lab equipment

•

s

®

Cartridge Heaters

111

Cartridge Heaters

FIREROD Immersion

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The small size and big capacity
of FIREROD cartridge heating units
make them ideal immersion heaters
in cramped quarters. When heating
liquids of low viscosity, FIRERODs
have the high watt density to pack
more heat into tight spots. For water
heating applications a rating of 150

2

to 300 W/in

is recommended.
(Laboratory tests show that under
certain conditions ratings as high as
700 W/in2are safe.) For longer life at
high watt densities:

• The FIREROD unit should be in

the main body of the liquid and
not in a restricted space.

• The FIREROD heater should be

covered with liquid at all times.

• The heater should not be allowed

to cycle on and off too frequently.

• Scale should not form.

When heating viscous liquids, such
as oils, watt densities must be kept
low to prevent carbonization at the
heater sheath. FIREROD cartridges
offer advantages for heating viscous
materials where long life and high
quality outweigh the usual economic
considerations. As in all immersion
applications, scale build-up on the
sheath and sludge on the bottom of
the tank must be carefully controlled
to assure long heater life.

Equipped with smaller threaded
fittings than conventional immersion
heaters, FIRERODs leave room for
more units in the same space.
Replacement of single FIREROD
units in multiheater assemblies is
fast and easy, and avoids discarding
the complete assembly.

Moisture proof seals are available
to give protection from damp
atmospheres outside the tank.

Built for sustained operation at
high temperatures, the FIREROD is
especially valuable in heat-transfer
applications with liquid metals. This
factor alone has made the FIREROD
heater a widely used component in
the development of nuclear power
systems.

Threaded fittings are furnished in
either stainless steel or brass.

®

FIRERODs with Incoloy

or 304
stainless steel sheaths are standard,
but other sheath materials can be
provided. Headers and sheath
material should be suited to the
material being heated.

Consult FIREROD section,
pages 75 to 76 for more
information.

112

Sheath Material Compositions

Sheath Chemical Composition

Material

Stainless Steels

304 0.08

316 0.08

Nickel Alloys

Incoloy®800 0.15/0.6 0.1 19/23 0.75 Bal 1.5 30/35 0.015 1.0 0.15/0.6

➀ Maximum

See application guide for additional sheath material composition.

Al

Co Cr Cu Fe Mn Mo Ni P S Si Ta Ti V W

C

➀

➀

18/20 Bal 2

16/18 Bal 2 ➀2/3 10/14 1

➀

8/12 1

➀

➀