COMPONENT - Strip & Ring Heaters
Installation Guidelines
Chromalox strip elements, in most cases, can be applied wth standard hardware. However,
for firm contact and best heat transfer, stocked Chromalox clamps are recommended.
Note - Heat insulating material should not be placed against the sheath of the heating
element.
Utility Clamps
Utility Clamps secure strip elements to flat surfaces or surfaces wth large radii
such as large tanks. hreaded studs are welded to surface, heaters are positioned,
then clamps are bolted down. Where more than one lamp is used, tighten nuts and
then back off 1/2 turn to allow for expansion..
Milled Plates
Milled Plates allow heaters to be held in position in platens and similar objects
wth a steel plate recessed to heaters width, thickness and positions, then screwed
to the working plate or surface. Clamping Bands Clamping Bands can be used to fi
rmly fasten strips longitudinally to large diameter cylindrical surfaces. Connecting
Lead Wires - Should be nickelplated copper, nickel or alloy. Copper will oxidize
and loosen connections. Do not use copper terminal lugs. See Accessories in this
section.
Clamping Bands
Milled Plates Clamping Bands can be used to firmly fasten strips longitudinally
to large diameter cylindrical surfaces.
Oven Mounting
Oven Mounting - Application of strip elements to ovens may be made simply wth the
use of welded-on studs and secondary insulation bushings. Mounting holes in tabs
are slotted to allow for expansion. Refer to Modifi cations in this section.
Selection Guides
|
Product To Be Heated
|
Temperature for Desired Products
|
Sheathed Material
|
Product Temp (°F)
|
Allowable Watt Density (W/In2)
|
|
SOLID
|
|
Molds, Platens, Dies, Pipes, Tanks
|
Up to 1400°F Clamp-On Applications
|
Rust-Resisting Iron
|
560
|
3
|
|
150
|
8
|
|
Chrome Steel
|
850
|
7
|
|
700
|
10
|
|
400
|
15
|
|
INCOLOY® 1
|
200
|
28
|
|
750
|
20
|
|
1100
|
8
|
|
1350
|
3
|
|
1400
|
2.5
|
|
AIR & GASES
|
|
Free Air Velocity- 1 ft/sec.
|
Up to 1400°F Bracket Mounted
|
Rust-Resisting Iron
|
500
|
3
|
|
100
|
8
|
|
Chrome Steel
|
950
|
7
|
|
800
|
10
|
|
500
|
15
|
|
INCOLOY® 1
|
1400
|
3
|
|
400
|
34
|
|
Rust-Resisting Iron
|
500
|
3
|
|
Free Air Velocity-4 ft/sec.
|
Up to 1400°F Bracket Mounted
|
250
|
8
|
|
Chrome Steel
|
1000
|
7
|
|
850
|
10
|
|
550
|
15
|
|
INCOLOY® 1
|
1400
|
5
|
|
600
|
34
|
|
Note:1 CSA Only
|
Strip & Ring Heater Modifications
Lengthwise Bending
Lengthwise Bending for clamping around pipes or
cylindrical vessels. Terminals may be located inside or outside of curvature for
all types listed.
3" Min. Inside Radius — Type S, SE, OT PT, th, NH, SNH, SN and ST.
6" Min. Inside Radius — Type SSE, SSEM, SSNH and SSNHM.
4-3/4" Min. Inside Radius — Type WS.
Cross-Section Curving
Cross-Section Curving — Type SE only, for clamping strips to 2,
2-1/2, 3, 4, 6, 8 and 12" pipes. For larger size pipe, use flat strips. Radii
available 1-3/16, 1-7/16, 1-3/4, 2-1/4, 3-5/16, 4-5/16 and 6-5/16" and 8-3/4”.
Terminals outside only.
Special Lengths — Type PT, SE, SN and SNH only. Special lengths
are made-to-order for instances in which the amount of heat applied to a surface
is critical and standard lengths are not suitable.
Special Voltage and Wattage — All types. Certain highly specialized
applications may require special ratings. However, most can be handled wth standard
heaters or standard ratings applied on an alternate voltage. Contact your Local
Chromalox Sales office.
Special Wattage Distribution — All types except td. When even temperatures
are required and end losses may cause an unsatisfactory temperature drop near the
edges, additional wattage can be provided at each end of the strip to make up for
losses.
Dual Contact Surface — Type SE only. 53-7/8" maximum A dimension.
Flush-top construction gives good contact for all surfaces of the strip heater.
Ideal for use in machined slots and installing between two smooth metal surfaces.
Without Mounting Tabs
Without Mounting Tabs — All types. Permits installing more heat
in a given confined space.
Specify “wthout mounting tabs” when ordering this feature.
Extra Strong Mounting Tabs — All types except WS. Recommended when
strips are bent lengthwise and tabs are used for bolting.
Monel® Sheath — Type S, SE, OT, PT, HSP and WS.
Stainless Steel Sheath — All types.
Cover for Seamless Strips, Factory Welded
Cover for Seamless Strips wth threaded Opening for Conduit — Cover
is welded to heater. Specify position of threaded opening ether on top of cover,
or as shown. Type SSE, SSEM and SSNHM.
Fahnestock® Terminals
Fahnestock® Terminals — Type S only. For quick temporary
connections where ambient temperatures do not exceed 150°C. Maximum recommended
amperage is 7.5 Amps.
Special Length Terminals — All types. Where a shorter or longer
terminal bolt than standard shown in drawing is needed, indicate length needed.
Rubber-Molded Terminals
Rubber-Molded Terminals — Type NS only. Used generally in low temperature
applications where moisture, condensation and high humidity are considerations.
Available in neoprene-rubber (to 190°F). Longer cold end or lower wattage is required
to assure temperature limit of molding material is not exceeded. End opposite terminal
is welded closed.
Special Lead Wire Terminal Construction
Special Lead Wire Terminal Construction
— All types. Specified most often when clearance is unavailable for standard terminals
and when lead wires are more suitable for wiring to nearby components.
Secondary Insulation Bushing
Secondary Insulation Bushings — All Types except NS. Must be used
when strips are mounted for air heating only or when connected in series on line
voltages 480V or above.
Note — To accommodate bushings, a 17/32 x 11/16" diameter
mounting hole in tabs should be specified for heaters. To Order
— Specify PCN 255716 (includes bushing and hardware for one strip) and quantity.
Strip & Ring Heaters Accessories
Protective Terminal Covers
— Types OT, PT, SE, WS and Seamless Types SSE, SSEM, SSNH and SSNHM. Helps guard
terminals from spillovers, dripping. Removable sheet-metal cover, wth Bx fitting,
is shipped separately.
OT-AC-1 (PCN 129242)
A-2 B- 21/2 C- 21/2
PT-AC-1 (PCN 255724)
A-17/8 B- 11/8 C- 13/4
SE-AC-1 (PCN 255724)
A-21/16 B-11/2 C- 2
Shims
— Types OT, PT, S, SE and th. Provide same advantage as flush-top construction and
can be used wth stock heaters. Shims are 0.031" thick, 29/32" wide and
lengths to fit heater.
Ceramic Post Terminal Insulators
Ceramic Post Terminal Insulators — All types except NS and SN. Use wth insulated
wire to help protect against electrical shock. Wires can leave terminal at any angle.
PCN 259805 (Nickel plated steel hardware)
PCN 255732 (Stainless steel hardware)
Porcelain Hi-Temp Insulation
Porcelain Hi-Temp Insulation —
For insulating buss bars spec. 51 porcelain insulators 1/2 L x 13/16" W wth
1/8 x 9/16" slot. 95 pieces per lb.
To Order — Specify pounds, PCN 269780 and porcelain insulators.
- For Insulating Bare Wires — Two types available:
- 1. Porcelain Tubing — 3/8" O.D. x 1/8"
I.D. x 6" L (may be broken for shorter lengths). Suitable for 10-gauge or smaller;
8-gauge takes No. 6 porcelain bead.
To Order — Specify quantity and PCN 263863.
2. Porcelain Beads — Listed in table below. Can be used when wiring
does not permit straight tubing.
When selecting porcelain beads for stranded wire, use next larger gauge wire and
use bead for that size (i.e., 10 gauge stranded wire requires a No. 6 bead).
Ambient Temperature Corrections for Insulated Wires
— Multiply ampacity values, in tables below, by the following correction factors
to determine current-carrying capacity at higher ambient temperatures.
|
Ambient Temp.
|
Nickel-Plated
MGS
Copper
Teflon
|
Nickel
|
|
°C
|
°F
|
Silicon
Glass
|
Teflon
Glass
|
MGS-Mics
Glass
|
|
30
|
86
|
—
|
—
|
—
|
1.36
|
|
50
|
122
|
0.98
|
0.97
|
0.98
|
—
|
|
60
|
140
|
0.95
|
0.94
|
0.95
|
—
|
|
70
|
158
|
0.93
|
0.9
|
0.93
|
—
|
|
80
|
176
|
0.9
|
0.87
|
0.9
|
—
|
|
90
|
194
|
0.87
|
0.83
|
0.87
|
—
|
|
100
|
212
|
0.85
|
0.79
|
0.85
|
1.22
|
|
120
|
248
|
0.79
|
0.71
|
0.79
|
—
|
|
140
|
284
|
0.72
|
0.61
|
0.72
|
—
|
|
149
|
300
|
0.65
|
0.5
|
0.65
|
1.12
|
|
177
|
350
|
0.58
|
0.35
|
0.58
|
—
|
|
204
|
400
|
0.49
|
—
|
0.49
|
1
|
|
232
|
450
|
0.35
|
—
|
0.35
|
—
|
|
260
|
500
|
—
|
—
|
—
|
0.87
|
|
269
|
550
|
—
|
—
|
—
|
—
|
|
300
|
572
|
—
|
—
|
—
|
0.7
|
|
Note — After exposure to high temperatures,
all wire insulation becomes brittle and will not wthstand repeated flexing.
|
Wire & Buss Bar
High-temperature wire and buss bar are recommended for connections to heater terminals
and for runs in heated zones. When ambient temperature exceeds maximum allowed for
insulated wire, use bare wire or buss bar wth porcelain insulators. Current-carrying
capacities should be carefully noted.
Buss bar is solid or perforated to facilitate wiring, especially when terminals
are in line. Perforated buss bar, has 11/32 x 7/32" slots on 7/16" centers.
When connecting elements wth buss bar, provide expansion loops between elements.
Buss bars may be used in multiples for higher ampacity (approx. 33-1/2% per buss
bar) than listed above, center.
|
High Temperature (Bare) Wire
|
|
Size AWG
|
Solid/S
Strand/F
|
Amp-
acity1
|
Nom.
O.D.
|
Model
|
PCN
|
|
550°F Max. Wire Temp. Nickel-plated Copper, Uninsulated
|
|
14
|
S
|
41
|
.064
|
CSB-14
|
263839
|
|
10
|
S
|
70
|
.102
|
CSB-10
|
263812
|
|
8
|
S
|
93
|
.128
|
CSB-8
|
263804
|
|
1000°F Max. Wire Temp. Manganese-nickel, Uninsulated
|
|
14
|
F
|
12
|
.075
|
AFB-14
|
269317
|
|
14
|
S
|
12
|
.064
|
AFB-14
|
263740
|
|
12
|
F
|
15
|
.097
|
AFB-12
|
269296
|
|
12
|
S
|
15
|
.081
|
AFB-12
|
269288
|
|
10
|
F
|
20
|
.12
|
AFB-10
|
269270
|
|
10
|
S
|
20
|
.102
|
AFB-10
|
269261
|
|
To Order — Specify PCN and quantity.
|
Insulated Wire
|
Size AWG
|
Solid/S
Strand/F
|
Amp-
acity1
|
Nom.
O.D.
|
Model
|
PCN
|
|
392°F Max. Wire Temp. Type A Nickel Wire
Silicone Rubber Treated Glass Braid Insulated 600V UL Listed
|
|
16
|
F
|
27
|
.224
|
3-CFI-16
|
263759
|
|
16
|
S
|
27
|
.224
|
3-CFI-16
|
263740
|
|
14
|
F
|
36
|
.237
|
3-CFI-14
|
263732
|
|
14
|
S
|
36
|
.237
|
3-CFI-14
|
263724
|
|
12
|
F
|
45
|
.263.
|
3-CFI-12
|
263716
|
|
12
|
S
|
45
|
.263
|
3-CFI-12
|
263708
|
|
10
|
F
|
60
|
.29
|
3-CFI-10
|
263695
|
|
10
|
S
|
60
|
.29
|
3-CFI-10
|
263687
|
|
482°F Max. Wire Temp. Type TGT,
Nickel-plated Copper, Tefl on® Impregnated
Glass Braid Insulated 600V UL Listed
|
|
14
|
F
|
39
|
.121
|
6-CFI-14
|
263791
|
|
14
|
S
|
39
|
.112
|
6-CFI-14
|
295398
|
|
12
|
F
|
54
|
.141
|
6-CFI-12
|
263783
|
|
12
|
S
|
54
|
.13
|
6-CFI-12
|
295400
|
|
10
|
F
|
73
|
.17
|
6-CFI-10
|
263775
|
|
10
|
S
|
73
|
.145
|
6-CFI-10
|
295419
|
|
8
|
F
|
93
|
.212
|
6-CFI-8
|
263767
|
|
482°F Max. Wire Temp. Tefl on® Tape and
Silicone Impregnated Glass Braid Insulated 600V UL Listed
|
|
14
|
F
|
39
|
.121
|
3-AFI-14
|
269253
|
|
12
|
F
|
54
|
.141
|
3-AFI-12
|
269237
|
|
10
|
F
|
73
|
.17
|
3-AFI-10
|
269210
|
|
842°F Max. Wire Temp. Nickel-clad
Copper, MGS-Mica Glass Insulated 600V
|
|
16
|
F
|
33
|
.065
|
6-CFIM-16
|
295355
|
|
14
|
F
|
44
|
.102
|
6-CFIM-14
|
295363
|
|
12
|
F
|
55
|
.118
|
6-CFIM-12
|
295371
|
|
To Order — Specify PCN and quantity.
1. See note 1 in Buss Bar Table.
2. These wiring recommendations are general in nature.
Confirm actual wire size and selection in accordance with
NEC (National Electrical Code).
|
Buss Bar
|
Buss Bar Model
|
DIM (In.)
|
Amp-acity1
|
PCN
|
|
Width
|
Thick
|
|
700°F Max. Wire Temp.
|
|
Solid
|
|
|
0.5
|
.032
|
18
|
346124
|
|
|
0.5
|
.064
|
28
|
346132
|
|
Perforated Slot Size = 7/32 Dia.
|
|
|
0.5
|
.032
|
9
|
346140
|
|
0.5
|
.064
|
16
|
346159
|
|
To Order — Specify PCN and number of feet.
1. these current values will cause the conductor to operate at 100°F
above surrounding ambient. Values may also be used for bare wire
wth porcelain tubes or bead insulation. Monel max. limit is 800°F.
|
SBK — the silicone boot termination kit provides electrical insulation
for strip heater terminals and leads with ring type insulated connector on one end
for bringing power to the strip heaters.
Silicone Boot Termination Kit with thermostat
|
Model
|
PCN
|
Temperature (F)
|
|
Closes
|
Opens
|
|
SBKT-1
|
386011
|
38
|
53
|
|
SBKT-2
|
386020
|
60
|
75
|
|
SBKT-3
|
386038
|
105
|
120
|
|
SBK
|
121890
|
N/A
|
N/A
|
Silicone Boot Termination Kit
SBKT — the silicone boot termination kit with thermostat used with
strip heaters provides an inexpensive way to maintain temperature in control cabinets,
panels and other small enclosures. In this application, strip heaters are used to
prevent freezing and corrosion, and to control humidity in enclosures with humidity
sensitive electronic components.
Element Clamps
Cast-iron clamps, for use with Chromalox strip and ring elements, retain their strength
at elevated temperatures to assure maximum sheath-to-surface contact. Resulting
uniform efficient heat transfer from internal resistance wire to the heated material
minimize hot spots on the element, contributing to long service life.
Clamp 6018 — Usually used in sets of two or more to clamp ring elements
to flat surfaces. 5/16" flathead machine screws are normally used with head
brazed or welded to work surface (PCN 263978).
Clamp 5971 — Use to clamp two strip heaters on 2" centers
using 5/16" studs spaced 5" apart (PCN 263636).
Clamp 6933 — Use to clamp two strip heaters on 3" centers
using 3/8" studs at 5" intervals (PCN 263644).
Clamp 5970 — Use to clamp three strip heaters on 2" centers
using 5/16" studs at 5" intervals (PCN 263652).
Clamping Bands
Type SC Clamping Bands — Provide permanently tight fit on cylinders,
nozzles, pipes and other round surfaces. Stainless steel band with alloy screw.
For small pipe diameters, strip elements should have cross-section curving (see
Modifications in the Components section).
For Most Satisfactory Results, bands should be spaced about 5 inches apart and should
be drawn up tight to assure good contact between heater or thermostat bulb and surface.
Mounting Studs
Mounting Studs — For use with Chromalox clamps. For all clamps
except No. 6933, studs are 5/16 — 18 x 1-1/2" Monel® (PCN 127845),
steel washer (PCN 127853), Monel® nut (PCN 127861). For No. 6993 clamp;
studs are 5/16" — 18 x 2" Monel® (PCN 127837).
Installation — Fasten studs to the work surface by welding, brazing
or threading. Use correct size stud to fit clamp. See Selection & Installation
Guidelines in the Components section. For temperatures over 750°F, stainless steel
studs are recommended.
Note — When tightening nuts, torsion should not exceed 10 foot
pounds maximum. Heaters must be allowed to expand. One center clamp should hold
heater. Nuts on other clamps should be backed off approximately 1/2 turn to allow
for heater expansion.
Download the Strip and Ring Heaters Selection and Installation Guidelines
