Size Your Heater
O.K.
... so it's right there in the Watt-Flex® cartridge heater
brochure. But you would be surprised by the number of questions
that are asked regarding items shown in the brochure.
But we are patient ... and always happy to talk with you about
applications. Here is the simple scoop:
The Available Diameters column below is pretty straightforward.
We have
all of the commonly requested diameters covered. Occasionally there
is an
oddball size requested. Consideration of the introduction of a
new diameter
must include many factors: new tubing diameter, end caps, reduction
dies,
inspection gauges, accessories and time (generation of elongation
factors
with trial runs, etc.).
Nominal Diameters are .005" or .027mm under the Spec.
diameter. This
allows a bit of room (fit) between the heater and the bore. The
diameter tolerance (Note 1) is +/- .002" or .050mm and must
be considered when specing the bore as discussed several newsletters
ago.
Table:
Watt-Flex Cartridge Heater Dimensions
|
Available
Diameters
|
Nominal Diameters (1) |
Standard Cold
Section at Terminal End |
Min - Max (2) Lengths
|
| 1/4” |
0.245” |
5/16” |
1 1/4”- 22” |
| 3/8” |
0.370” |
3/8” |
1 1/2” - 36” |
| 1/2” |
0.495” |
5/8” |
2” - 50" |
| 5/8” |
0.620” |
5/8” |
2 1/2” - 72” |
| 11/16” |
0.683” |
5/8” |
3 1/2” - 64” |
| 3/4” |
0.745” |
5/8” |
3 1/2” - 90” |
| 1" |
0.9925" |
1” |
10” - 60” |
| 8.0 mm |
7.875 mm |
8.000 mm |
38 - 660 mm |
| 10.0 mm |
9.875 mm |
9.500 mm |
38 - 915 mm |
| 12.0 mm |
11.875 mm |
15.875 mm |
50 - 1140 mm |
| 12.5 mm |
12.375 mm |
15.875 mm |
50 - 1140 mm |
| 15.0 mm |
14.875 mm |
15.875 mm |
65 - 1250 mm |
| 16.0 mm |
15.875 mm |
15.875 mm |
65 - 1525 mm |
| 20.0 mm |
19.875 mm |
15.875 mm |
100 - 1525 mm |
| (1) Tolerances: ±.002" (
1/4" to 3/4"); ±.0025 (1"); ±.05mm
(8mm-20mm) |
| (2) Tolerances: ± 3%
with 3/32"minimum; ±2% above 20 " (500 mm) |
The cold terminal end of the heater is a function of the pin onto
which the resistance
wire is terminated. And the Min.-Max. lengths are subject to tolerance
just as
diameters are (Note 2). The tolerance is +/- 3% of the length to
20" and +/- 2%
over 20". This tolerance is a function of the elongation that
occurs as a result of
heater compaction, and must be considered when specifying the length
against
the heat sink.
If you have any questions about the impact of tolerances and specifications
on the application, we are always happy to help ... give us a call.
|
