ALTANA Gradient-Oven - Handbuch (Seite 87)

ESCKey - ESC key and STOP key have
the same function. Pressing the ESC
key returns you to the previous point
of the menu. When baking, pressing
the key interrupts the process and,
depending on the SETUP setting, will
allow it to cool down to the
temperature set. If ‘Cool-down No’ is
selected under SETUP, the
temperatures of the heating bank
remain at the last set gradient.
Exhaust Fumes - An electronically
controlled fan generates a slight
vacuum inside the heating zone. This
allows all solvents, water vapors, etc.
that are released to be carried away
through the rear wall of the housing.
Through the addition of an 80 mm ø
exhaust tube (included in the delivery)
the exhaust fumes can be drawn off
directly through a flexible tube or by
means of an extractor system.
Consequently, no turbulences of air
will affect the surface of the test panel
(see ‘Air Circulation’). From time to
time the perforated panels of the
pressure platform will require
cleaning.
Exhaust Zone - In general, industrial
ovens have exhaust zones. The
released solvents are environmentally
friendly disposed prior to the paints
being baked.
Fans - The gradient-oven is fitted with
three weak-current fans. Two of them
are employed to cool the heating
bank, the third serves to draw off
vapors at the rear of the instrument.
All fans are supplied with 24 V low
voltage.
Film Application Device - The film
application device, Cat. No. 2628, is
required for the application of wet
paints. With film applicators or
applicator frames, use of the film
application device allows an even film
to be applied to the test panel.
Front Shutter - The front shutter is fixed
at the front of the gradient-oven to
prevent users from injuring their
fingers or hands while the panel
holder carriage is moving. Only when
the front shutter is in the closed
position, the interlock switch for the
electric circuit of the motor is closed.
Fuses - Four fuses are located in the
right side panel. For type and rating
please refer to technical data.
Glass Plate - Special glass is required
to insulate the area between the
heating elements and test panel.
Thickness: between 1.2 and 1.6 mm.
Temperature stability up to 350 °C.
The surfaces of the glass plates are
factory-tempered prior to use. Glass
plates that are exposed for a long
time to great temperature differences
can become rippled. Rippled glass
plates impair the even transfer of heat
from the heating bank to the test
panel (see ‘Surface Temperature’).
Through pinpoint pressure and
simultaneously high temperatures
cracking and splintering is likely to
result. Every kind of impurity will
affect the transfer of heat from the
heating bank to the test panel. Clean
using paint removers, scrapers and
solvents. To replace, see operating
instructions under ‘Maintenance’.
gradient-oven - Around 10 -15 ovens
were built by TNO in Delft,
Netherlands, and distributed in
Europe from 1975 to 1979. After
building two prototypes (similar to the
TNO ovens) in 1979, BYK went for a
new concept. Using microprocessors,
a low cost solution was found to
control more than 10 heating
elements at the same time. BYK has
had an oven constructed that has 45
heating elements fitted with 45 Pt-100
sensors and can generate constant
fühlern. Hier wird zwar nur das
integrierte Signal gemessen, z.B. 100
°C - 100 °C, jedoch ist hier die
Gewähr gegeben, dass diese gemes-
senen Werte auf ± 1 °C der Oberflä-
che des Prüflings entsprechen,
vorausgesetzt, dass das Prüfblech
keine Welligkeiten aufweist. Die
nächst genauere Methode für die
Oberflächenmessung im Bereich
eines jeden Heizstabes ist die
Messung mit Infrarot - Thermome-
tern. Voraussetzung: Das Blech muss
tiefschwarz-matt eingefärbt sein. Der
Emissionsfaktor des IR-Thermome-
ters muss exakt eingestellt sein und
das Prüfblech darf praktisch nur
einmal verwendet werden, da sich die
Beschichtung durch die Temperatur
ändert und somit keine
Reproduzierbarkeit erreichen lässt.
(Erreichbare Genauigkeit bei Eigen-
fehler des Messgerätes von ± 2%, ±1
Digit = ca. ± 3 °C bei Temperaturen
bis 150 ° Reproduzierbarkeit = ± 1
°C.) Messmethoden mit Umschlag-
farben oder Schmelzsubstanzen
liegen durch die individuelle Bestim-
mung außerhalb der
Kontrollmöglichkeiten für die Heiz-
bank.
Glasscheibe - Spezialglas, wird zur
Isolierung zwischen Heizelementen