Page 1
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
Page 2
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
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Page 3
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
Page 4
Band Heaters
0.625 in.
(16 mm)
1
7
/
16
in.
(37 mm)
3
1
/
2
in. for 3
1
/
2
-5
15
/
16
in. I.D.
4" for 6-39
15
/
16
in. I.D.
1
13
/
16
in.
(46 mm)
Special Mica
Barrel and Nozzle
Variations
Continued
Holes and Notches
An economical way to provide
access for instrumentation is to
specify an oversize gap between
the heater ends. Holes and notches
in the sheath should be specified
only when all the cylinder surface
adjacent to the hole or notch must
be heated. Required holes may be
provided in nearly any location as
Two Piece Band Heaters
long as there is at least one inch
(25 mm) between the hole and one
side of the heater. Standard hole
sizes up to two inches (51 mm)
diameter. For proper hole and/or
notch location, a
dimensional
drawing or customer supplied
sample heater is required.
Two-piece construction is available
on heaters three inches (76 mm) or
greater in diameter. Heaters three
inches wide or less with post
terminals have one terminal on each
end. Heaters over three inches wide
with post terminals have the two
terminals side by side on one end.
On two-piece units with leads, also
specify the power supply voltage. The
power supply voltage is the voltage to
Outside Diameter
This variation is specially designed
and constructed to heat the inside
diameter of cylinders, i.e., large
diameter blown film dies. All the
terminations and mounting hardware
are located on the I.D. of the heater.
which the heater will be wired. For
example, a two-piece band that is
240VÅ(ac) per half may be wired in
series to a 480VÅ(ac) power supply.
In this case the band heater lead wire
insulation must be rated for
480VÅ(ac). To order, specify two
piece band heater, with volts and
watts per half and power supply
voltage.
Consult W
and terminations.
atlow for available sizes
To order, specify
outside diameter heater.
4
Metallic Terminal Box
erminal boxes are attached to the
T
heater to cover the terminals for an
added safety feature. Conduit may
be attached to the box through 7⁄8
inch (22 mm) diameter holes in the
ends of the box. T
erminal box is
available on two-piece heaters.
When ordering, specify
terminal
box.
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W A T L O W
13/4 in.
(
44 mm)
25/16 in.
(
59 mm)
21/
1
6
in.
(
52 mm)
21/4 in.
(57 mm)
113/
1
6
in.
(
46 mm)
15/
1
6
in.
(33 mm)
Band Heaters
Special Mica
Barrel and Nozzle
Variations
Continued
High Temperature “Quick Disconnect” European Style Plugs
These plugs provide the simplest
and safest way to apply power to
band heaters. The combination of
high temperature male and female
quick disconnect plug assemblies
eliminates all live exposed terminals
and electrical wiring that can be a
potential hazard to employees or
machine. Maximum 15 amps at
Å(ac), maximum 240 volts.
240V
To order, specify vertical or
horizontal European plug.
Band Heaters
Vertical
Right Angle
Code # N6027AF049
Horizontal
Code # N6027ZZ028
Special Construction Variations
Straight
High Temperature “Quick Disconnect” European Style Female Adapters
Available as an accessory item that
must be used in conjunction with
high temperature “quick
disconnect” European style plugs.
Specify code number N6027AF049
or N6027ZZ028 and quantity.
Ceramic Terminal Covers
Stock Option
A convenient and economic way to
insulate post terminals and are
sized for standard length posts.
Ceramic terminal covers also have
a 10-24 screw thread size. These
are supplied as an accessory item
. Specify
Square,
Code # Z-4918
Rectangular and He
and shipped separately
Z-4918 and quantity.
x Bands
Squar
e and r
ectangular heaters are
made in either one or two-piece
construction. These units are ideal
for heating dies on plastic extruders
or the barr
extruders. Hex-shaped heaters are
commonly used on the hex-shaped
els of twin scr
ew
tion of the nozzle injection
por
molding machines. Hex-shaped
heaters are made to exact customer
cations. To order, specify
specifi
square or rectangular heaters. A
dimensional drawing or customer
supplied sample heater is
required.
5
Page 6
Band Heaters
Designed to Accomodate
Standard Bayonet Adapter
Figure 1 Figure 2 Figure 3
"
B"
"A"
"B"
"
A"
"B"
"
A"
Special Mica
Barrel and Nozzle
Special Construction
Variations
Continued
Square, Rectangular and Hex Bands (continued)
Clamping Styles
The preferred clamping style is
illustrated in Figure 1 showing bentup flange clamping. This clamping
style applies a uniform clamping
force at the corners.
Figure 2 shows bent-up flanges or
built-in strapping bracket at the
side.
The least preferred clamping style is
shown in Figure 3. The one-piece
heater does not apply a uniform
clamping force.
Hinged Two-Piece Band
The hinged, two-piece band heater
is connected with a reinforced
hinge. It can be opened and closed
as often as necessary resulting in
easy installation and removal.
To order, specify
hinged two-piece
band and watts and volts per each
half.
6
Thermocouple Bracket
The thermocouple bracket
simplifies the installation of an
external thermocouple with a
bayonet adapter. The standard
location for the adapter is 90
degrees from the gap. Sizes
available are 1⁄8 (3.18 mm),
1
⁄4 (6.3 mm) and 3⁄8 (9.53 mm)
To order, specify thermocouple
bracket.
Page 7
W A T L O W
Top ID
B
ottom ID
Height
1 to 3 in.
Diameter
Less than 2 in. wide:
5
/
16
in. (8 mm)
More than 2 in. wide:
1
1
/
3
2
in. (9 mm)
in. (14 mm)
9
/
16
0.563 in.
(14 mm)
Spot Welded
Band Heaters
Special Mica
Barrel and Nozzle
Special Construction
Variations
Continued
Clamping Variations
Cone Shapes
Cone shaped heaters are ideal for
applications where heat is required
for hoppers or funnels. The
preferred method of attachment is
with bent-up flange clamping. Cone
shaped heaters are made to exact
customer specifications.
To order, specify
cone shape
adapter. A dimensional drawing
or customer supplied sample
heater is required.
HV Wedge-Lok
HV wedge-lok is designed to
provide excellent clamping where
mounting space is limited. It is available with Type A and L leads only.
Clearance from I.D. of the heater to
the outside edge of the wedge-lok is
5
⁄16inch (8 mm) nominal. Available on
certain sizes from stock. To order,
specify
HV wedge-lok.
Band Heaters
Standard and Low-Profile
Clamping Strap
The standard clamping strap
requires 9⁄16 inch (14 mm) clearance
above the heated surface, at the
barrel nuts. When clearance is
limited, smaller barrel nuts can be
used which require only 3⁄8 inch
(9 mm) clearance. The clearance
required by the clamping screw
Welded Barrel Nuts
An ideal way to provide access
for instrumentation is to specify an
oversized gap between the heater
es
ends. If the clamp strap inter
fer
with the positioning of the
instrumentation device,
depends on the screw length and
the diameter of the heater. The lowprofile clamping strap is standard on
units less than 13⁄8 inches (45 mm)
wide and utilizes a 1⁄2 inch (13 mm)
wide strap. Consult Watlow for more
information. To order, specify low-
profile clamping strap.
welded barrel nuts are recommended.
Maximum gap is one inch (25 mm)
Specify
welded barrel n
dimensional location
uts with
and gap
dimension when ordering.
7
Page 8
Band Heaters
(19 mm)
in. (11 mm)
(11 mm)
1 in.
(25 mm)
(17 mm)
3
/4 in.
7
/16 in.
11
/16 in.
7
/
16
A
s required
Clamping Pad
Special Mica
Barrel and Nozzle
Clamping Variations
Continued
Non-Stock Option
Clamping Tabs
Tabs—or lock-up flanges—are
available. However, the special mica
band heater and strap design
provides superior clamping and
improved heat transfer and should
be used whenever possible. To
order, specify
clamping tabs.
Clamping Pads
Clamping pads have a hole to allow
easy fastening to machine barrel.
Clamping pads are used when an
obstruction hinders a standard
clamping strap from fitting
completely around the machine
barrel.
To order, specify
clamping pads
and degrees coverage.
Termination Variations
Post Terminal Options
Standard post terminals have a
7
threaded length of
and require
3
⁄16 inch (11 mm)
⁄4 inch (19 mm)
clearance from the cylinder.
Terminals with 11⁄16 inch (17 mm)
threaded lengths are available that
r
equire one inch of clearance. Button
terminals require only 7⁄16 inch (11 mm)
clearance. Maximum amperage for
post ter
minals is 35 amps. To order,
specify standard, long or button
terminals.
Three-Phase or Dual Voltage
A third terminal can be added
to provide dual voltage or
three-phase.
Standard terminal location on
heaters three inches (76 mm) wide
or less is one terminal at each end
of the heater centered on the width.
Standard
Long
Button
On heaters thr
, the ter
wider
ee inches wide or
minals ar
e located
side-by-side on one end. Special
minal locations are available. To
ter
or
der
, specify
dual v
olta
e
g
or
three-phase.
8
Page 9
W A T L O W
0.38 in.
(9 mm)
0.30 in
(8 mm)
Band Heaters
Special Mica
Barrel and Nozzle
Termination Variations
Continued
Heaters rated at less than 250 volts
use UL
for operations to 250˚C (482˚F) as
standard. Lead insulation UL®rated
for operation to 450˚C (850˚F) may
be required in high temperature
applications where the leads are
shrouded or enclosed with the
heater. All heaters rated at more
than 250V
®
approved lead insulation
Å(ac) use this wire.
Type B
Two fiberglass-insulated lead wires
exit in a single metal braid for good
abrasion protection, lead flexibility
and wiring convenience. Leads are
two inches (51 mm) longer than
braid. To order, specify
and length.
Type E
Type B
Type C
Two fiberglass lead wires exit a
single tightly woven metal braid for
good abrasion protection, lead
flexibility and wiring convenience.
Leads are two inches (51 mm)
longer than the braid. To order,
specify
Type F
Type C and length.
Band Heaters
Loose metal braid encloses two
fiberglass leads for good abrasion
protection, lead flexibility and wiring
convenience. Leads are two inches
(51 mm) longer than the braid. To
order, specify
Type H
A stainless steel, fl
encloses the leads for superior
mechanical protection where lead
abrasion is a par
Leads are two inches (51 mm)
longer than the conduit. To order,
specify Type H
Type E and length.
exible conduit
ticular pr
and length.
oblem.
Loose fiberglass sleeving encloses
berglass leads for additional
two fi
insulation protection where high
temperature or minor abrasion is
Leads ar
esent.
pr
(51 mm) longer than the sleeving. To
order, specify T
Type K
Flexible lead wires exit vertically
from the heater. These leads can be
bent adjacent to the heater for a
quick and easy connection. To
order, specify Type K and length.
e two inches
ype F
and length.
9
Page 10
Band Heaters
11/4 in.
(32 mm)
1
1
/4
in.
(32 mm)
15/8 in.
(41 mm)
1
/2 in. N.P.T.
Special Mica
Barrel and Nozzle
Termination Variations
Continued
Right Angle Armor Cable
Armor cable provides superior
protection to lead wires where
abrasion can cause damage. The
standard leads are 12 inches
(304.8 mm) of armor cable over
14 inches (355.6 mm) of flexible
Removable Armor Cable
leads. Right angle armor cable is
available on any clamping or
construction variation.
To order, specify
.
cable
right angle armor
Installation Procedures
1.Install heaters over a clean
surface.
Install clamp straps, tightening
2.
until screw cannot be tightened
additionally. On heaters with
multiple straps, alternately tighten
each strap until no additional
tightening occurs.
3.To insure that the heater is
properly seated on the barrel, it is
advisable to tap around the
circumference of heater with a soft
mallet. This will result in a final
ming of the heater to the
confor
cylinder. Generally after this is
done, operators can get an
additional tur
n or two on the
Removable armor cable is
recommended on applications
where removable armor is required.
It is available on any clamping or
construction variation. The fitting will
clamp screw. Each screw should
have an ultimate torque value as
in below chart.
4.When installing terminal lugs,
torque the top nut to 12 in.-lbs.
The bottom nut should be held
by a wrench when tightening the
top nut.
5.After the machine has been run
accept the standard armor cable
connector. The standard flexible
leads are 14 inches (355.6 mm).
To order, specify removable armor
cable.
Note: This retightening must be
done when the heaters are cold. If
the heater becomes loose due to
normal operating and cycling the
strap can be r
although frequent adjustments are
not advisable. It is advisable to
check bands for tightness every
three to four months.
for its initial heat up, it is
advisable to retighten the
clamping bands.
Clamp Strap Torque Specifications
Strap Width Strap Allen Pan Head
in. (mm) Screw Type Type
7
⁄8 (22.2)
5
⁄8 (15.8) 10 - 24 30 - 35 lb/in 30 - 35 lb/in
1
⁄2 (12.7) 8 - 32 25 lb/in 25 lb/in
10 - 24
60 - 75 lb/in
30 - 35 lb/in
etightened,
10
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