Introduction - Fisher Scientific 650 Series Instruction Manual

Introduction

4
Fisher Isotemp 650/750 Series Programmable Muffle
Furnaces are available in three sizes: small (Model 14),
medium (Model 58) and large (Model 126). All models
provide PID microprocessor temperature control at oper-
ating temperatures from 50 to 1125 °C (90 to 2057 °F).
Furnace chambers are molded from alumina silicate
ceramic fibers. Use of this material provides low thermal
mass for fast heat-up and cool-down, as well as an
unusually low exterior furnace temperature for safe opera-
tion. The furnace is heated by electric resistance ele-
ments embedded in easily removable side and base pan-
els. The heating elements are designed to ensure
extended service life, even in atmospheres characteristic
of high-sulfur coal and coke samples.
Temperature readouts and control parameters are shown
on two red 7-segment displays. Two LED's indicate when
heater power is being applied or when an over-tempera-
ture error condition is encountered. Temperatures can be
displayed in either °C or °F.
For operation with chamber atmospheres other than air
(N2, C02, etc), external gas supplies connect easily
through a provided 3/8-inch port. An Injection Port Kit
(10-550P) connected to the exhaust port allows
convenient venting of the chamber.
Isotemp furnaces incorporate a variety of safety features.
When the furnace door is opened, power is automatically
cut to the chamber heating elements. The heater power is
also cut out when the chamber temperature exceeds the
set temperature by 25°C (45°F) or more. The alarm con-
dition is indicated on the display while the alarm LED is
lit. A ventilated base design prevents damage to the
bench or countertop.
The system microprocessor permits the user to customize
a heating program of up to 24 ramp and soak steps. The
model 750 can store four 24 step programs, while the
model 650 can store one 24 step program. If desired,
a soak period of up to 23 hours, 59 minutes and 59 sec-
onds may be interspersed between any two successive
ramps.