Physitemp Instruments BFS-30MP - Manual (Page 11)

WARNING! DO NOT USE DRY ICE ON TOP OF THE STAGE
Several customers have reported using Dry Ice (CO2) to speed up the
freezing of tissue specimens mounted on their BFs series freezing stage.
This may cause several problems. Putting dry ice, which is at -85°C,
directly onto the metal surface of the stage fools the controller into
believing that the top plate has reached its set temperature and so it
shuts off power to the thermoelectric cooling elements.
If there is too much dry ice on the plate it can cause irrepairable damage
to the thermoelectric modules which are designed for a temperature gra-
dient of 60°C. With dry ice on the surface of the stage this gradient can
exceed 100°C. This can cause severe mechanical stress on the compo-
nents of the module due to thermal expansion and contraction and can
literally shear it apart.
Bearing the above cautionary information in mind, it is possible to use
dry ice of top of the specimen itself to reduce its temperature quickly.
Do not put the dry ice directly on the metal surface of the stage.
Please contact our technical department for further assistance.
1-800-452-8510
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