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TUBULAR HEATERS
 The most versatile of all electric heating elements,
the tubular heater is capable of being formed into virtually
any configuration. The basic design consists of a helical coil
of nickel-chromium resistance wire precisely centered in a metal
sheath. This coil is surrounded by magnesium oxide powder which
is vibration loaded to insure even density throughout the length
of the heater. This entire assembly is then reduced to the finished
diameter, compacting the MgO and "freezing" the coil
in the center of the heater. The range of ratings, sizes, materials
and terminations available makes the tubular heater adaptable
to many industrial, commercial and scientific applications. |
Copper Sheath: Water
heating, water solutions non-corrosive to copper.
Steel Sheath: Immersion
in oils, molten salt baths, alkaline cleaning solutions, tars
and asphalt. Also suitable for clamping to metal surfaces and
casting into aluminum.
Stainless Steel Sheath: Corrosive liquids, food processing equipment.
Incoloy Sheath: Air
heating, radiant heating, cleaning and degreasing solutions,
plating and pickling solutions, corrosive liquids.
Other sheath materials are also available
for application considerations. Commonly specified are 316 stainless
steel and Carpenter 20 stainless steel for corrosive immersion
heating, copper clad steel for metal casting, Inconel for high
temperature applications, and titanium for severely corrosive
solution heating. Porcelain and ceramic coatings can also be
provided for corrosive atmospheres in process air applications,
immersion heating, or for other application considerations.
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| Minimum Unheated Section On Each End: |
| 1-1/4" |
11-1/2" to
50" |
| 1-1/2" |
51"
to 80" |
| 1-5/8" |
81" to 110" |
| 1-3/4" |
111"
to 140" |
| 2" |
141" to 170" |
| 2-1/4" |
171"
to 192" |
| 2-1/2" |
193" and
Longer |
|
Sheath
Material |
Max. Sheath
Temperature |
Max. Watts
Per. Sq. In. |
| Copper |
350°F/175°C |
55 |
| Steel |
750°F/400°C |
22 |
| Stainless
Steel |
1200°F/650°C |
30 |
| Incoloy |
1500°F/815°C |
40 |
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* Other diameters
are available including metric sizes
| Tolerances and Limitations |
| Sheath Diameter
±.005* |
.210 |
.250 |
.312 |
.375 |
.430/.437 |
.475/.490 |
.625 |
| Minimum
Sheath Length |
11-1/2 |
11-1/2 |
11-1/2 |
11-1/2 |
11-1/2 |
11-1/2 |
11-1/2 |
| Maximum Sheath Length |
144 |
144 |
420 |
480 |
420 |
312 |
250 |
| Maximum
Voltage |
240 |
250 |
250 |
480 |
600 |
600 |
600 |
| Maximum Amps |
12 |
15 |
30 |
30 |
40 |
40 |
40 |
| Minimum
OHMS/inch of EHL |
.177 |
.100 |
.060 |
.040 |
.040 |
.040 |
.050 |
| Maximum OHMS/inch
of EHL |
8 |
17 |
21 |
21 |
21 |
21 |
17 |
| Wattage |
+5% -10% |
| Resistance |
+10% -5% |
| Sheath
Length |
±1/2% |
| Effective Heated
Length |
±1% |
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 (PDF file - 327k)
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