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1.
INSTRODUCTONS
Since
no
single
design
can
provide
the
best
heater
for
all
applications,
Hanil
electric
heat
engineering
company
manufactures
cartridge
heaters
in
two
basic
designs.
Which
of
the
two
designs
to
use
is
determined
primarily
by
the
required
watt
density
of
the
heater.
We
therefore
refer
to
the
two
types
as
either
HI-watt
LOW-watt,our
trade
name
for
the
high
density
heaters,
or
standard(low
watt
density)
heaters.
While
we
have
standard
designs
for
the
construction
of
booth
HI-watt
and
LOW-watt
cartridge
heater, We
have
always
been
ready
to
design
heaters
for
special
or
unusual
applications.
The
illustration
below
shows
only
a
few
of
these
special
designs,
which
include
hollow
cartridge
heaters,flat
heaters
with
pilot
bits
and
heaters
for
three
phase
operation.
Take
advantage
of
our
engineering
and
design
staff
to
help
solve
your
specific
problem.
cartridge
heater,
in
the
simplest
terms,
is
a
cylindrical,
metallic
Sheathed
device
used
to
produce
heat
by
passing
an
electric
current
through
a
resistance
wire
inside
the
sheath
Though
sometimes
used
to
heat
fluids
or
gases,
their
shape
and
size
makes
them
particularly
suitable
for
the
heating
of
machine
parts
such
as
dies,
press,
molds,platens
and
other
process
machinery.
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![한일전열엔지니어링/생산품목/카트리지히터[cartridge heater]](a_img/CARTRIDGE-K.gif) |
In
these
applications,
the
heater
is usually
inserted
into
a closely
Fitting
hole
drilled
in the
part
to be
heated.
The
heater
is designed
to raise
the
temperature
of the
part
to a
specific
point,
and
to maintain
that
temperature
through
the
process
in which
the
machine
is used.
much
more
is involved
in the
design
and
manufacture
of cartridge
heaters
than
is indicated
in the
brief
description
above.
Construction
is influenced
by a
great
many
factors
such
as temperature,
wattage
and
watt
density,
voltatage
and
phase,
heater
accessibIlity
and
desired
operating
life,
tolerance
of fit
in the
hole
in which
the
heater
is inserted,and
the
space
available
in the
part
to be
heated.
(2).
CONSTRUCTIONS
2-1.
RESISTANCE
WIRE
Of
the
many
types
of resistance
wire
available,only
a few
are
suitable
for
used
in high
watt
density
heaters,
of these
few,
only
the
finest
is used
in the
hi-watt.an
alloy
of 80%
nickel
and
20%
chromium,it
provides
the
best
combination
of structural
strength,low
temperature
coefficient,high
temperature
operating
characteristics
and
protective
Oxidation
properites.
2-2.
INSULATOR
The
granular
size
and
shape,
purity,
and
final
compacted
density
of the
magnesium
Oxide
used
greatly
affects
heater
performance.
Specially
selected
for
this
applications,
the
material
used
in the
hi-watt
provides
a unique
of all
of thease
factors
which
insure
the
greatest
possible
structual
and
dielectric
strength
while
maintaining
very
low
resistance
to heat
flow.
2-3.
SHEATH
ELEMENT
While
stainless
steel,
inconel,
incoloy
an other
alloys
are
used
in high
watt
density
cartrdige
heaters,
Hanil
electric
heat
engineering
company
Uses
only
Incoloy
in the
HI-wat.
This
alloy
alone
provides
the
best
combination
of phsical
strength
and
resistance
to virtually
all
types
ocorrosion.
Including
heat
and
chemical
corrosion
and
heat
scaling.
Not
only
is the
finest
alloy
used,but
the
well
thickness
is much
heavier
than
is usually
found
in heaters
of this
type.
This
heavy
wall
enables
the
heater
to better
withstand
the
stresses
encountered
during
many
heating
and
cooling
cycles,
greatly
ncreases
the
physical
and
removal,and
helps
maintain
the
compacted
density
of the
magnesium
oxide
and
other
internal
components
for
long
life
and
consistent
performance.
2-4.
INSULATION
Generally,thermal
conductivity
and
dielectric
strength
are
increased
with
the
compaction
of
the
magnesium
oxide:
however,heater
quality
is actually
reduced
if compaction
increases
to the
point
at which
the
magnesium
oxide
granules
are
pulverized
while
being
compacted.
In
the
hi-watt,
all
components
of the
compaction
process,
ncluding
equipment,Technique
and
the
magnesium
oxide
itself
have
been
designed
to produce
the
optimum
in compaction
without
reaching
that
point
past
which
Heater
life
and
quality
is actually
reduced.
2-5.
LEAD
WIRE
Power
is supplied
to the
hi-watt
through
flexible
nickel-clad
copper
leads
rated
for
temperatures
of 250°C. The
leads
are
firmly
attached
to large
diameter
solid
terminal
pins
of nickel
alloy
which
are
internally
connected
to the
resistance
wire.
The
junction
of lead
wire
and
terninal
pin
is totally
enclosed
in a
fiber
glass
which
provides
both
excellent
electrical
insulation
and
high
resistance
to abrasion.
The
solid
terminal
pins
are
long
enough
to allow
field
reconnection
to new
flexible
leads
when
necessar
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