Properties; General; Physical And Chemical Properties - SCHOTT Instruments SLK 1 Gebrauchsanleitung

1

Properties

General

The main application of the Laboratory hot plates with ceramics material consists in heating up aqueous
solutions without inflammable portions in glass vessels. Considering that the interior of the Laboratory hot
plates and the glass-ceramics heating zones heat up, any other application have to be checked carefully
to know whether they might result in hazardous situations.
The SCHOTT glass-ceramics material has special thermal properties. The glass-ceramics heating zone is
almost free of thermal expansion and has a resistance to thermal changes from – 200 °C to + 700 °C. A
hot glass-ceramics heating zone may be quenched with ice-cold water without suffering any damage.
In addition to the thermal properties the glass-ceramics material has the chemical stability and surface
quality of glass. Owing to the high infrared permeability the heat energy is transmitted quickly and with lit-
tle loss only. The residual-heat indicator of the Laboratory hot plates warns of hazards of burning. The re-
sidual heat can be used in an energy-saving manner to preheat another vessel.
The glass-ceramics surfaces remain plane, are pore-free, and do not have bordering frames or soiling an-
gles. SCHOTT Laboratory hot plates are therefore easy to clean.
The back panel of the Laboratory hot plates contains a bore hole with an M8 thread for accommodating a
∅ 10 mm tripod rod (not included in the scope of delivery, item no. TZ 1510).
The functions of the Laboratory hot plates are controlled via sensor keys.
The application limits are described in the "Warning and safety instructions" chapter.
Physical properties of the glass ceramics
Coefficient of thermal expansion α:
Specific weight ρ:
Module of elasticity E:
Knoop hardness under 1N load:
Max. temperature stability: T
Static loading capacity:
Chemical properties of the glass-ceramics material
Hydrolytic resistance DIN ISO 719:
Alcali-fastness
Acid-fastness
The SLK 1 and SLK 2 Laboratory hot plates including their radiant elements are suitable for quick heat-
ing-up of liquids. The highest heating stage, i.e. << 9 >> corresponds to a heating output of 1.2 kW or
1.8 kW, respectively.
On the right heating/stirrer zone of the SLK 2-T Laboratory hot plate, you can furthermore keep the tem-
perature of the liquid constant. A temperature sensor, Pt 1000 Resistance Thermometer, immersed into
the liquid and connected at the back panel of the Laboratory hot plate records the temperature. Using the
corresponding sensor keys you can switch the temperature control on and select a command temperature
between the ambient temperature and 100 °C in increments of 1 K. The command temperature is indi-
cated above the sensor keys. The temperature may vary in the range from ± 2 °C to ± 5 °C, depending on
the vessel, the volume of the liquid, and the ambient temperature.
The combination of the SLK 1 Laboratory hot plate with radiant element and a Laboratory hot plate with
foil heater with additional stirring function results in the SLK 6 Laboratory hot plate. Owing to its properties,
two heating zones of which one with an additional stirring function, you can heat up a medium quickly and
subsequently stir it under continuing heating. You just have to change the heating zone.
The right heating/stirrer zone offers you, as well as the Laboratory hot plate SLK 2-T, the possibility of the
temperature control.
An over-temperature guard protects the Laboratory hot plates from overheating.
permanent:
max
DIN 52 322 / ISO 685:
DIN 12 116:
12
+ 20 ... + 300 °C: - 0.25 ⋅ 10
+ 20 ... + 700 °C: + 0.10 ⋅ 10 -
3
2.58 g / cm
2
92 kN / mm
> 575 HK (test according to ISO 9385)
700 °C; at short term (1 min max.): ≤ 850 °C
2
0.1 kp / cm (approx. 1 N / cm
Hydrolytic class 1
class 2
class 3
-6 1
K-
K -
6 1
2
)