Datasheet
1
3
Introduction
Design
Guide
Polyimide
Heaters
Silicone
Rubber
Heaters (foil)
Standard
Polyimide
& Rubber
Rubber
Heaters
(wire-wound)
Mica Heaters
Thermal-Clear
Heaters
All-Polyimide
Heaters
Sensors,
Controllers &
Accessories
Reference
Sal es and Support
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Description of
Thermal System
Heat a tank containing 2 kg of chemi-
cal solution from 20°C to 50°C in 10
minutes. The space available for
mounting the heater is 4" × 5" (102 x
127 mm). Input voltage is 120 VAC.
Heat moving film in a thermal proces-
sor. A sheet of polyester film weigh-
ing 5 g must be brought from 25°C to
90°C every 2 seconds. The heater will
measure 2" × 12" (51 x 305 mm) and
will be mounted on a metal platen.
Input voltage is 120 VAC.
An LCD heater must be capable of
bringing the 6" × 8" (152 X 203 mm)
display from-55°C to 0°C in 5 minutes
and maintaining it there.
Input voltage is 120 VDC.
Wattage
requirements
From Thermal Calc*, we need 450 watts
minimum for warmup plus losses.
From Thermal Calc*, we need 275 watts
minimum for warmup plus losses.
From Thermal Calc*, we need 50 watts
for warmup and 20 watts for mainte-
nance of temperature.
Electrical
parameters
R = E²/W = 120²/450 = 32 Ω R = E²/W = 120²/275 = 52 Ω R = E²/W = 28²/50 = 16 Ω
Heater
selection
Choosing polyimide for chemical resist-
ance, the best choice is
HK5490R27.7L12E
Specifying silicone rubber for lower
cost, the best choice is
HR5433R44.1L12A
From Minco’s standard Thermal-Clear™
heaters we choose model
H6709R14.8L12B
Actual wattage Wattage is 120²/27.7 = 520 W Wattage is 120²/44.1 = 327 W Wattage is 28²/14.8 = 53 W
Watt density Watt density = W/effective area =
520/17.74 in² = 29 W/in² (4.5 W/cm²)
Watt density = W/effective area =
327/21.80 in² = 15 W/in² (2.3 W/cm²)
Watt density = W/effective area =
53/48 in² = 1.1 W/in² (0.2 W/cm²)
Installation From watt density charts we specify
Acrylic PSA with aluminum backing (E
option). This is rated to 31 W/in² (4.8
W/cm²) at 50°C.
Any type of heater mounting will han-
dle the watt density. We will factory
vulcanize the heater for lowest installed
cost.
We choose Acrylic PSA backing for
convenience (B option). The watt den-
sity is well within the rated maximum.
Leadwire
current
AWG 24 leadwire current rating is 7.5 A.
Actual current is:
I = 120/27.7 = 4.3 A (OK).
AWG 24 leadwire current rating is 7.5 A.
Actual current is:
I = 120/44.1 = 2.7 A (OK).
AWG 30 leadwire current rating is 3 A.
Actual current is:
I = 28/14.8 = 1.9 A (OK).
Control The CT16A controller with optional
AC744 solid state relay will handle the
current.
The customer integrates a custom con-
troller into other electronic circuits.
A CT198-1005 Heaterstat™ will control
the heater. Its setpoint will be
adjustable from 6 to 62°C. We have
chosen a model with a higher range in
order to ensure that the LCD itself
reaches 0°C. We know the setpoint will
have to be higher because it controls
the heater element which runs hotter
than the surface beneath it.
Sensor An S665 Thermal-Tab™ RTD will be
mounted to the side of the tank.
An S247 thin-film RTD will be potted
into a hole in the platen. A thermostat
with 100°C setpoint will provide
overtemperature shutoff.
None: The heater acts as the sensor!
Custom
options
An AP heater would provide a higher
watt density for faster warmup (at
higher cost). A rubber or mica heater
would allow more watts for faster
warmup, if acceptable in the applica-
tion.
The sensor and thermostat could be
integrated into the heater.
Placing the lead connections on an
external tab would remove the lead
bulge from the display area. Switching
to a sensor and CT325 for control,
instead of the Heaterstat, would allow
higher wattage and finer control.
Examples of Thermal Systems