Watlow Band Heaters Data sheet

W A T L O W

SST. Strap

Resistance Ribbon

Mica Insulation

Zinc Steel

Post Terminals

Band Heaters

Special Mica
Barrel and Nozzle

For over 80 years, Watlow has been
solving complex and unique
application problems with standard
mica barrel and nozzle heaters.
Watlow is continuously improving
design and application knowledge
through engineering expertise and
experience with numerous OEM and
end-user applications.

This has resulted in the development
of many specialty variations in
construction resulting in the best
heat solutions. This catalog contains
a sampling of what can be done.
Please contact a local Watlow sales
engineer for custom applications.

Performance Capabilities

• Sheath temperatures to 480°C
(900°F)

• Watt densities to 55 W/in
(8.5 W/cm2)

Features and Benefits

UL®component recognition

• Available for applications up to

480°C (900°F)

Patented clamping strap

• Assures efficient heat transfer

w mass design

Lo

• Allows fast heat-up and quick

response

Design variations

• Provides user convenience and

heater protection

Applications

• Extruders

• Blown film dies

• Injection molding machines

• Other cylinder heating

applications

2

Band Heaters

UL®is a registered trademark of
Underwriter’s Laboratories, Inc.

1

20 30 40 50

Watt Density—W/in

2

700

500

300

800

900

1000

1100

600

400

200

10 60

500

400

300

200

24 68

100

Cylinder Temperature—°F

Cylinder Temperature—°C

Watt Density—W/cm

2

10 in. (254 mm) Dia.

3 in. (76.2 mm) Dia.

1

1

/

2

in. (38.1 mm) Dia.

Band Heaters

Special Mica
Barrel and Nozzle

Applications and Technical Data

Operating Factors

Use lowest watt density per the graph
below. A close match of the heat
supplied to the actual requirements will
reduce temperature over-shoot, reduce
cycling and increase the life of any
band heater used.

Calculate the
for the heater using:

Heated Area x Maximum
Watt Density

Calculate the heated area of the band
heater by subtracting the no-heat area
from the total area in contact with the
cylinder (3.14 x I.D. x width). Subtract
the no-heat area at the terminals
(from table) and any additional
no-heat area caused by holes, slots
or oversize gaps.

Determine the maximum watt density
of the heater from the Maximum
Allowable Watt Density graph.
The curves are based on narrow
heaters mounted on a smooth, steel
cylinder. Apply the necessary
correction factors:

• For heaters 21⁄4 inches (57 mm) to
ve inches wide (127 mm), multiply

fi
watt density by 0.8.

• For high expansion cylinders

(aluminum or brass), r
watt density by 3 W/in2(0.46 W/cm2).

• For heaters 21⁄4 inches to five inches

wide installed on a high expansion
cylinder, reduce watt density by a
total of 3 W/in2(0.46 W/cm2) only.

•

For r
than smooth, machined finish,
reduce watt density by 3 W/in
(0.46 W/cm2).

• For heaters that will be insulated

or enclosed, contact Watlow for
specific watt densities.

safe maximum wattage

egular cylinder sur

educe the

faces other

2

No-Heat Area for Special Mica Band (Post Terminals)

Heater Size No-Heat Area

Heater

Type in. (mm) in. (mm) in. (mm)

One Piece

Two Piece 3 (76.2) or more

Diameter Width

Less than 2 (50.8) Up to 6 (152.4) 1 (25.4) x width

2 (50.8) or more

MMaaxxiimmuumm AAlllloowwaabbllee WWaatttt DDeennssiittyy

Up to 3 (76.2) 11⁄2 (38.1) x width

More than 3 (76.2) 1 (25.4) x width

Up to 3 (76.2) 3 (76.2) x width

e than 3 (76.2) 2 (50.8) x width

Mor

at Terminals

2

W A T L O W

Band Heaters

Special Mica
Barrel and Nozzle

Physical Limitations of Variations

Check the table to be certain the
variations and lead arrangements
being ordered are available on the
heater size required. If you need to
exceed any limitations, please
contact a Watlow representative.

hysical Limitations of Variations

P

Heater Type Min. Max. Min. Max.

1 pc. 15⁄16 (33.3) 22 (559)
2 pc. 3 (76.2) 44 (1117)5⁄8 (15.8) 15 (381)
Expandable:
Narrow 13⁄4 (44.4) — — 1 (25.4) 3 (76.2)
Wide 13⁄4 (44.4) — — 2 (50.8) 6 (152.4)
O.D. heater
1 pc. 3 (76.2) 22 (559) 1 (25.4) 6 (76.2)
2 pc. 3 (76.2) 44 (1117) 1 (25.4) 6 (76.2)
Type K leads
Type L leads
Type E leads 1
Type F leads 11⁄2 (38.1) 22 (559)
Type H leads 11⁄2 (38.1) 22 (559)
Type B leads 11⁄2 (38.1) 22 (559)
Post terminals 15⁄16 (33.3) — — 1 (25.4) 15 (381)
Type A leads
Type C leads 1
Terminal box 31⁄2 (88.9) — — 13⁄8 (34.9) 15 (381)
Plug w/bracket 3 (76.2) — — 31⁄2 (88.9) 15 (381)
3-phase — — — — 3 (76.2) 15 (381)
European plug
1 pc. vertical 1
1 pc. horizontal 3 (76.2) 22 (559) 2 (50.8) 15 (381)
2 pc. vertical 3 (76.2) 44 (1117) 1 (25.4) 15 (381)
2 pc. horizontal 3 (76.2) 44 (1117) 2 (50.8) 15 (381)
HV Wedge-Lok 1 (2.5.4) 3 (76.2) 1 (25.4) 6 (76.2)
Clamping tabs 2 (50.8) — — 1 (25.4) 15 (381)
Welded barrel nuts
1 pc. 2 (50.8) 22 (559) 1 (25.4) 15 (381)
2 pc. 4 (101.6) 44 (1117) 1 (25.4) 15 (381)

Diameter Width

in. (mm) in. (mm) in. (mm) in. (mm)

5

⁄8 (15.8) 15 (381)

3

⁄4 (19.05) — — 1 (25.4) 15 (381)

3

⁄4 (19.05) — —

1

⁄2 (38.1) 22 (559)

3

⁄4 (19) — —

5

⁄16 (33.3) — — 1 (25.4) 15 (381)

5

⁄16 (33.3) 22 (559) 1 (25.4) 15 (381)

5

⁄8 (15.8) 15 (381)

5

⁄8 (15.8) 15 (381)

5

⁄8 (15.8) 15 (381)

5

⁄8 (15.8) 15 (381)

3

⁄4 (19.05) 15 (381)

5

⁄8 (15.8) 15 (381)

Band Heaters

Variations

Note: Some combinations of maximum and minimums cannot

occur on the same heater.
Standard gap is 1⁄4 inch (6.35 mm)

Different Widths

The 11⁄2 inch (38 mm) wide heater is
the most ef

ficient due to maximum
clamping action. Heaters are
available in widths from 5⁄8 inch

(16 mm) to 15 inches (381 mm).
Multiple clamping straps ar
for heaters more than three inches
(76 mm) wide.

Expandable Heaters

Heaters three inches (76 mm) wide
or less are constructed with a
notched sheath. Heaters wider than

e constructed with an

ee inches

thr

ar

shipped open and should not be
closed and r
twice. To order, specify

expandable.

expansion seam. These heaters are

eopened mor

ovided

e pr

e than

3