Cleaning & Servicing - Cole-Parmer MP-200 Serie Manual De Instrucciones

Measuring a Melting Point
WARNING:
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. MP-200D-HR 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 start/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 (MP-200D-HR)
or at the fixed 2°C per minute on the MP-200D
(the plateau light will go out and the ramping
and heating lights will both be illuminated - see
4
If the unit has been used recently
figure 1.)
12. Observe the sample until the melt occurs and
record the temperature from the digital display.
13. MP-200D-HR only – It is possible to freeze the
temperature display on the MP-200D-HR 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.
3. Two fuses are mounted on the rear of the IEC
connector (both 'Live' and 'Neutral' mains
supply leads are fused). These fuses can be
removed and replaced by hand. ALWAYS replace
the fuse by ones of the correct values shown