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Idiomas disponibles
Idiomas disponibles
Measuring a Melting Point
N.B. If the unit has been used recently the block may
be too hot for your sample. If this is the case press
the stop button and allow the unit to cool before
proceeding.
1.
Prepare sample by placing a small amount in the
end of a glass capillary tube.
2.
Decide on a suitable plateau temperature. This
should be approximately 10°C below the expected
melting point of the sample.
3.
Check that all 3 function lights are extinguished.
If not, press the stop button.
4.
Press and hold the plateau set button (the plateau
light will flash). The display will now show the
current plateau temperature.
5.
The desired plateau temperature may now be set
using the arrow keys to scroll the display up
or down as required.
6.
Release the set button. The new plateau
temperature is now set and all function lights
will go out (The plateau setting can be checked at
any time during operation by pressing and holding
the plateau set button). This action will not
interfere with the operation of the unit).
7.
SMP20 only – Decide on an appropriate ramp rate,
between 1ºC per minute and 10ºC/min. Results
obtained at 1ºC per minute will be the most
accurate, while more approximate results can
be obtained faster at higher ramp rates.
Setting the ramp rate is the same procedure as setting
the plateau except you need to use the ramp set button
instead of the plateau set button.
8.
Insert the tube into the side of the heating block
via the holes provided. For convenience this can
be done from either side of the block. Look down
the magnifier and position the tube so that the
sample can be observed clearly.
Caution: The heating block may be HOT.
9.
Press the start or stat/stop key. The unit will quickly
heat up to the plateau temperature (the heating
light will be illuminated - see figure 1)
10. Once the plateau temperature has been reached
the plateau light will be illuminated as well as
the heating light - see figure 1.
N.B. At low plateau temperatures there may be some
overshoot. Wait until the plateau light comes on before
proceeding in order to ensure that the temperature has
stabilised.
11. Press the start button again. The block will
begin to heat at the pre-set ramp rate (SMP20)
4
SMP10_20_PRINT_Manual.indd 4
or at the fixed 2°C per minute on the SMP10
(the plateau light will go out and the ramping
and heating lights will both be illuminated - see
figure 1.)
12. Observe the sample until the melt occurs and
record the temperature from the digital display.
13. SMP20 only – It is possible to freeze the
temperature display on the SMP20 using the
hold button. Once pressed the temperature
display will hold (ramping light flashing) to allow
more time to record the melt temperature.
Press hold again to return to the actual block
temperature.
14. After the melt has occurred press the stop or start/
stop button. All function lights will go out and the
unit will cool to ambient temperature.
15. Pressing the start button again will cause
the unit to return to the plateau temperature
instead of ambient. The heating light will come on
even if the temperature is above the plateau and
the unit is, in fact, cooling.
Cleaning & Servicing
WARNING: Ensure the unit is disconnected from
the mains electricity supply and allowed to cool
before attempting any cleaning or servicing.
Cleaning
Periodically clean the instrument using a damp cloth
and mild detergent solution. Do not use harsh or
abrasive cleaning agents. Broken melting point tubes
may be removed from the block simply by pushing
them through with a piece of wire or similar tool.
For access to the block for more thorough cleaning the
sample chamber cover must be removed.
1.
Remove the 3 retaining screws and lift off the
cover.
2.
Loosen the screw retaining the metal plate but do
not remove completely.
3.
Push the plate to one side.
4.
The glass window in the top of the block may now
be removed.
Servicing
Any repairs or replacement of parts MUST only be
undertaken by suitably qualified personnel. There are
two replaceable fuses on the rear of the IEC mains
connector. The cause of any fuse failure should be
investigated and corrected.
Proceed as follows:
1)
Ensure the unit is disconnected from the mains
supply.
2)
Unscrew the four screws on the base of the unit
and remove the base plate. Do not disconnect or
pull on the base earth bonding wire.
25/05/2010 11:37
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