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FINNED TUBULAR HEATING ELEMENTS

finned tubular heaters are suitable for use in a wide variety of forced air heating applications. The steel units are suitable for applications where the sheath temperature will not exceed 850° F. For higher temperatures or in applications where corrosion is a problem these can be made in stainless steel or monel.

Units can be assembled in a frame to provide a compact duct heater. Because of the greater surface area provided by the heat transfer fins, it is possible to fabricate units providing greater kW capacities, with lower operating temperatures. 

Features of Finned Tubular Heaters are:

  1. Seamless steel sheath material.
  2. High purity MgO Powder, compacted to provide maximum heat conductivity and optimum dielectric strength.
  3. Type ‘A’ 80/20 resistance wire sized to provide the lowest wire watt density for maximum life, precision wound to provide uniform heat flux over length of element.
  4. Fusion welded junction between cold pin resistance wire giving superior life.
  5. Bends recompacted to restore MgO density on formed units.
  6. Continuous steel fin edge wound and copper brazed to heater sheath. This provides maximum heat transfer from sheath to fin, without vibration.
  7. Fin and sheath are painted with high temperature aluminum paint to resist oxidation.

Optional Features are:

  1. Threaded fittings for mounting
  2. Ceramic to metal end seals for high temperature or corrosive environments
  3. Other sheath and fin materials
  4. High temperature ceramic coating
  5. Custom bracket mountings
  6. Custom terminal options
  7. Also available in smaller diameter units
  • Straight Finned Standard Sizes
  • U-Bent Finned Tubular Heaters

60 Watts per Lineal Inch Steel Sheath with Steel Fins
11 Watts/SQ. In. Straight Length
Watts
Volts
A
B
C
E
1000
240
480
22 ¾
18 ¾
25
2″
1250
240
480
26
22
28 ¼
2″
1500
240
480
31
27
33 ¼
2″
2000
240
480
39 ⅜
35 ⅜
41 ⅝
2″
2500
240
480
47 ¾
43 ¾
50
2″
3000
240
480
56
52
58 ¼
2″
4000
240
480
72 ¾
68 ¾
75
2″
5000
240
480
89 ⅜
85 ⅜
91 ⅝
2″
6000
240
480
106
102
108 ¼
2″
75 Watts per Lineal Inch Steel Sheath with Steel Fins
14 Watts/SQ. In. Straight Length
Watts
Volts
A
B
C
E
1000
240
480
19 ⅜
15 ⅜
21 ⅝
2″
1250
240
480
22 ¾
21
25
2″
1500
240
480
26
22
28 ¼
2″
2000
240
480
32 ¾
32 ¾
35
2″
2500
240
480
39 ⅜
35 ⅜
41 ⅝
2″
3000
240
480
46
42
48 ¼
2″
4000
240
480
59 ⅜
55 ⅜
61 ⅝
2″
5000
240
480
72 ¾
68 ¾
75
2″
6000
240
480
86
82
88 ¼
2″
100 Watts per Lineal Inch Steel Sheath with Steel Fins
18 Watts/SQ. In. Straight Length
Watts
Volts
A
B
C
E
1000
240
480
16
12
18 ¼
2″
1250
240
480
18 ½
14 ½
20 ¾
2″
1500
240
480
21
17
23 ¼
2″
2000
240
480
26
22
28 ¼
2″
2500
240
480
31
27
33 ¼
2″
3000
240
480
36
32
38 ¼
2″
4000
240
480
46
42
48 ¼
2″
5000
240
480
56
52
58 ¼
2″
6000
240
480
66
62
68 ¼
2″

60 Watts per Lineal Inch Steel Sheath with Steel Fins
Hairpin 11 Watts/SQ. In.
Watts
Volts
A
C
E
F
1000
240
480
11 ½
12 ⅝
2″
2″
1250
240
480
13 ⅛
14 ⅜
2″
2″
1500
240
480
15 ⅝
16 ¾
2″
2″
2000
240
480
19 ⅞
21
2″
2″
2500
240
480
24
25 ⅛
2″
2″
3000
240
480
28 ⅛
29 ¼
2″
2″
4000
240
480
36 ½
37 ⅝
2″
2″
5000
240
480
44 ⅞
46
2″
2″
6000
240
480
53 ⅛
54 ¼
2″
2″
75 Watts per Lineal Inch Steel Sheath with Steel Fins
Hairpin 14 Watts/SQ. In.
Watts
Volts
A
C
E
F
1000
240
480
9 ⅞
11
2″
2″
1250
240
480
11 ½
12 ⅝
2″
2″
1500
240
480
13 ⅛
14 ¼
2″
2″
2000
240
480
16 ½
17 ⅝
2″
2″
2500
240
480
19 ⅞
21
2″
2″
3000
240
480
23 ⅛
24 ¼
2″
2″
4000
240
480
29 ⅞
31
2″
2″
5000
240
480
36 ½
37 ⅝
2″
2″
6000
240
480
43 ⅛
44 ¼
2″
2″
100 Watts per Lineal Inch Steel Sheath with Steel Fins
Hairpin 18 Watts/SQ. In.
Watts
Volts
A
B
C
E
1000
240
480
8 ⅛
9 ¼
2″
2″
1250
240
480
9 ⅜
10 ½
2″
2″
1500
240
480
10 ⅚
11 ¾
2″
2″
2000
240
480
13 ⅛
14 ¼
2″
2″
2500
240
480
15 ⅚
16 ¾
2″
2″
3000
240
480
18 ⅛
19 ¼
2″
2″
4000
240
480
23 ⅛
24 ¼
2″
2″
5000
240
480
28 ⅛
29 ¼
2″
2″
6000
240
480
33 ⅛
34 ¼
2″
2″

TUBULAR HEATING OPTIONS

THREADED FITTINGS

Threaded fittings are furnished with nuts and optional fiber gaskets, washers and lockwashers. Fittings are silver soldered, welded or mechanically pressed (staked) to the sheath. Welding requires sheath and fitting material compatibility. Standard elements may be provided with two fittings, one for each terminal end. Two-pass elements may be provided with only one fitting.

THREADED FITTING CHART
C
Element Diameter		 Fitting Part No. Shoulder Type Material A
Thread Size		 B
Length		 D
Shoulder Thk		 E
Head Size		 F
Min. Thrd.
Length
0.250/0.260 60000425 Hex SST 7/16-20UNF 0.56 0.13 0.63 0.425+
0.250/0.260 60000428 Hex BRS 1/2‐20UNF 0.50 0.13 0.75 0.43
0.250/0.260 86-2-C-3 Round BRS 1/2‐20UNF 0.63 0.13 0.75 0.55
0.26 86-3-C-74 Hex BRS 1/2‐20UNF 0.69 0.19 0.75 0.61
0.32 60000326 Hex SST 7/16-20UNF 0.56 0.13 0.63 0.425+
0.32 1007121 Round BRS 7/16-28UNEF 0.56 0.31 0.75 0.51
0.32 86-22-C-1 Hex BRS 1/2‐20UNF 0.50 0.19 0.75 0.43
0.32 86-22-ZC-2* Hex BRS 1/2‐20UNF 0.50 0.19 0.75 0.43
0.32 86-3-UZ-1 Hex 303 SST 1/2‐20UNF 0.63 0.13 0.75 0.488+
0.32 60000431 Round SST 1/2‐20UNF 0.81 0.13 0.75 0.675+
0.32 1007139 Round BRS 1/2‐20UNF 0.88 0.31 0.75 0.80
0.32 86-37-C-1 Hex BRS 1/2‐20UNF 1.00 0.25 0.75 0.93
0.32 1007219 Round BRS 9/16-18UNF 0.50 0.13 1.00 0.42
0.32 1007142 Round BRS 5/8-18UNF 0.50 0.31 1.00 0.42
0.32 86-62-C-1 Hex BRS 5/8-18UNF 0.75 0.19 0.88 0.67
0.32 60000384 Hex SST 5/8-18UNF 0.81 0.13 0.88 0.73
0.38 60000324 Hex BRS 1/2‐20UNF 0.56 0.13 0.75 0.49
0.38 60000198 Hex 303 SST 9/16-18UNF 0.69 0.13 0.75 0.542+
0.38 86-3-UZ-81 Hex 303 SST 9/16-18UNF 1.00 0.13 0.88 0.854+
0.43 86-47-C-1 Round BRS 9/16-18UNF 1.00 0.25 0.75 0.92
0.43 86-36-C-2 Hex BRS 5/8-18UNF 0.50 0.19 0.88 0.42
0.43 60000320 Hex SST 5/8-18UNF 0.63 0.13 0.88 0.48
0.43 86-36-C-1 Hex BRS 5/8-18UNF 0.75 0.19 0.88 0.67
0.43 60000396 Hex SST 5/8-18UNF 1.00 0.13 0.88 0.854+
0.43 86-3-C-7 Hex BRS 5/8-18UNF 1.06 0.19 0.88 0.98
0.43 60000352 Hex BRS 3/4-16UNF 0.81 0.19 1.00 0.72
0.43 60000337 Hex SST 3/4-16UNF 1.06 0.19 1.00 0.97
0.48 1007127 Round BRS 5/8-18UNF 0.56 0.31 1.00 0.48
0.48 1006846*** Round STEEL 5/8-18UNF 0.56 0.13 1.00 0.417+
0.48 1007118 Round BRS 5/8-18UNF 0.81 0.31 1.00 0.73
0.48 1007276 Round SST 5/8-24UNEF 0.75 0.13 1.00 0.625+
0.48 1007279 Hex SST 3/4-16UNF 0.38 0.19 1.00 0.28
0.48 1000058** Hex STEEL 3/4-16UNF 0.50 0.13 0.88 0.41
0.48 1007225 Hex BRS 3/4-16UNF 0.88 0.25 1.00 0.78
0.48 1007228 Hex SST 3/4-16UNF 0.88 0.25 0.88 0.78
0.48 1007273 Hex SST 3/4-16UNF 1.06 0.19 1.00 0.97
0.49 60000389 Hex BRS 5/8-18UNF 0.50 0.13 0.88 0.42
0.49 60000138 Hex SST 5/8-18UNF 0.88 0.19 0.88 0.729+
0.49 60000317 Hex SST 3/4-16UNF 0.56 0.13 1.00 0.47
0.49 60000070 Hex SST 3/4-16UNF 1.06 0.19 1.00 0.97
0.63 60000410 Hex STEEL 7/8-14UNF 1.00 0.13 1.13 0.83+
0.63 60000373 Hex SST 7/8-14UNF 1.13 0.13 1.13 0.955+
0.63 60000008 Hex SST 7/8-14UNF 1.38 0.13 1.13 1.205+
0.63 60000375 Round STEEL 7/8-14UNF 1.88 0.13 1.25 1.705+

+ Fitting has a 1/16” weld projection not included in the “F” dimension shown. Consult factory for details.
* Tin plated brass
** This fitting is copper plated steel, normally furnished on finned tubular elements with palnut type locknuts standard. Gaskets are not furnished unless specified.
*** Nickel plated steel
Other fittings available, contact factory.

MOUNTING PLATES

MOUNTING PLATES

Mounting plates provide a simple, convenient means of holding elements in place in an airstream and other applications where the element is not immersed in a liquid. Stainless steel plates are mechanically pressed (staked) or tack welded to sheathed elements.
The mounting plates shown to the right are standard configurations for .475” diameter elements. Consult factory for other diameters and configurations.

Heating Element
Configuration		 Mounting Plate
Type Material
2-1/2” C-C U-Bent I Stainless
Straight or Two-Pass II Stainless

 

terminal assembly options

Terminal # 1

Threaded Terminal (standard)

Description:
Stainless steel stud with threaded length
Optional:
Insulators available in silicone rubber (std) or optional mica or ceramic where available
Use:
For lead attachment in the field.
600V rating
Thread Sizes* OAL Standard INS Standard
(Insulator Dim)
6-32 1” 0.50”
8-32
10-32
1/4-20

* 6-32 thread is standard for .250 and .260
Element Diameters, 10-32 thread is standard for all other Diameters.
Other thread size, INS and OAL lengths available upon request.

Terminal # 2

Quick Connect Terminal

Description:
Standard 1/4” plated steel quick connect configuration

Optional:
Insulators available in silicone rubber (std) or optional mica or ceramic where available

Use:
For connection to matching female terminal on field funished lead. 30 amp max, see table for voltage rating
oltage
Range		 OAL Standard
(Straight terminal)		 OAL Standard
(90 Deg terminal)		 INS Standard
(Insulator Dim)
0-250V 0.75” 0.813” 0.25
251-600V 1” 1.063” 0.5
Terminal # 3

 

Weld Nut

Description:
Tab with internal thread is welded to
terminal pin and furnished with terminal
screw

Use:
Where it is more convenient to use this
terminal orientation.
Voltage
Range		 OAL Standard
(Straight terminal)		 OAL Standard
(90 Deg terminal)		 INS Standard
(Insulator Dim)
0-250V 0.813” 0.563” 0.25
251-600V 1.063” 0.813” 0.5
Terminal #4

Neoprene Insulated Leads

Description:
Standard Bare Copper or Tin Plated Copper Conductors insulated with Neoprene. 90oC Neoprene insulation with thickness of 5/64” or 1/16”.

Use:
Used primarily for internal wiring or wiring of defrost and refrigeration applications up to 600V. See Neoprene and Expoxy filled Terminal #5 for applications that require protection for wet (immersed) refrigeration type applications.
Neoprene exhibits supreme abrasion, cut-through oil, and solvent resistance. Neoprene is also known for its long service life and wide ranges of temperature and usability. It is remarkably flame retardant and self-extinguishing. (Military products often incorporate Neoprene.)

PVC Insulated Leads

Description:
Standard Bare Copper or Tin Plated Copper Conductors insulated with PVC. 105oC PVC insulation with thickness of 1/32”.

Use:
Used primarily for internal wiring of appliances up to 600V or with thickness of 1/16” for internal wiring of refrigeration equipment. See Valox Terminal #5 for applications that require protection for moist refrigeration type applications.
PVC is relatively inexpensive, with the potential to be used in diverse applications. It is flame, moisture, and abrasion resistant. It also holds up against gasoline, ozone, acids, and solvents. PVC should not be used when flexibility and an extended flex life are required at low temperatures.

Silicone Insulated Leads with Glass Braid (SRG)

Description:
Stranded Tin Plated Copper Conductors insulated with Silicone Rubber and Glass Braid. 200oC Silicone Rubber insulation with thickness of 1/32”.

Use:
Used primarily for internal wiring of applicances up to 600V. SRG is the standard suppied insulation material, with the exception of defrost and refrigeration applications.

Type TGGT Leads

Description:
Stranded Nickel-Clad Copper Conductors insulated with PTFE tapes and Glass Braid. 250oC PTFE tapes with thickness of 1/64” covered by wrapped fiberglass yarns and a treated glass braid jacket.

Use:
Used where the leadwire is exposed to high temperatures such as in industrial processing up to 600V.

Mica Insulated Leads with Glass Braid (MGT)

Description:
Stranded Nickel-Clad Copper Conductors insulated with Mica Glass Tapes and Glass Braid. 450oC Glass reinforced Mica tapes with thickness of 1/32” and a treated glass braid jacket.

Use:
Used where the leadwire is exposed to extremely high temperatures up to 600V.
Standard Supplied Wire Gauge Limit Amps
18 10
16 15
14 20
12 30
terminal # 5

Defrost Terminal

Description:
Neoprene or Valox, Injection Molded overmold terminal

OR

Epoxy Filled Metal Cup Terminal

Description:
Epoxy resin fills a metallic adapter enclosing the connection between lead wire and element cold pin.

Use:
Primarily defrost applications and others where water may drop on the terminal end. UL Recognized under File SA3254.
Type Material Type Element Sizes OD OAL Location Description
Overmold QC Neoprene One-Pass 0.250 – 0.315 0.4375 1.0625 Moist T Series
Epoxy Cup SM Epoxy/Metal One-Pass 0.315 0.5625 1.25 Wet Blank Series
Epoxy Cup LG Epoxy/Metal One-Pass 0.475 0.5625 1.75 Wet Blank Series
Overmold Neoprene One-Pass 0.250 – 0.375 0.4375 1.75 Wet W Series
Overmold Neoprene One-Pass 0.430 – 0.490 0.75 1.75 Wet W Series*
Grounding Strap (Optional)

Description:
To ground long straight single-pass finned tubular elements, eliminating arcing due to secondary currents.

Use:
Recommended for straight single-pass finned tubular elements over on expansion end. Verify adequate expansion clearances.
End Seal Options

End Seal #1:

Epoxy Barrier

Description:
Epoxy resin fills a 1/4” cavity above the magnesium oxide insulation, to form a barrier against moisture.

Use:
For applications where low to moderate humidity may be present in the terminal area. For use at 266oF maximum for 0.315 element and above. 194oF maximum for 0.260 elements and below.

End Seal #2:

RTV Barrier

Description:
RTV sealant forms a barrier against moisture.

Use:
For high temperature applications where temperatures may range up to 392oF or 428oF.

End Seal #3:

Hermetic Seal

Description:
Ceramic to metal hermetic seal is soldered to the element sheath and cold pin.

Use:
Absolute moisture seal up to 1000oF.

Element Sheath:
Available in element diameters .430 and .475, consult factory for other availability.
Element Sheath Diameter INS Standard (Integral Ceramic Insulator Dim) OAL Standard
0.430 0.5 2.125”
0.475 0.5 2.125”
Alternate element sheath diameters available upon request.
Insulator Options

Insulator #1:

Silicone Rubber (standard)

Description:
General applications where terminal temperatures do not exceed 400oF. 1/4” thick insulation furnished up to 250V; 1/2” thick up to 600V. (Standard insulator unless otherwise specified

Insulator #2:

Mica

Description:

Applications where terminal temperatures do not exceed 900oF. 1/4” thick insulation furnished up to 250V; 1/2” thick up to 600V.

End Seal #3:

Insulator #3:

Ceramic

Description:
Applications where terminal temperatures do not exceed 1400oF. 1/4” thick insulation furnished up to 250V; 1/2” thick up to 600V.
CONTACT US
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Southeast Thermal Systems

301 N. NC 16 Business Hwy., #155 Denver, NC  28037

Phone: 704-399-4248
Fax: 704-399-4167

“We offer economical solutions that work with existing systems, increase production, reduce cost, and most importantly, add to your bottom line. “

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