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small ball of ice will form on the end of the well tube. This helps thicken
the ice mantle at the bottom of the reentrant well.
4.
The dry ice is loaded into the cup and the spaces are filled with ethanol
(approximately 100ml). The Quick Stick must be cooling before insert-
ing it into the TPW. Insert it to the bottom of the reentrant well. The ra-
dius at the bottom helps center it in the well.
5.
Once the Quick Stick is inserted into the TPW cell, fill the space around
the tube with alcohol (ethanol) up to within approximately 1 cm below
the water level in the cell. This helps to prevent ice from bridging across
the top of the cell during mantle formation. A special heat sink is pro-
vided that fits around the TPW cell that also helps prevent bridging.
Slide the heat sink onto the cell up to the level of the water. Adjust the
centering bushing until the heat pipe is centered in the reentrant tube.
6.
It will take approximately 40 to 60 minutes to form mantle. Be sure that
there is no ice bridging at the top of the TPW cell. One fill of the Quick
Stick cup is usually sufficient to form a good mantle.
Remember that the magnification of the water makes the mantle appear
larger than it actually is. Remove the cell from the fixture and tilt so that
you can view the ice through the vapor only to see the actual size of the
ice mantle.
7.
Once the mantle is formed, remove the Quick Stick from the TPW cell.
Keep the Quick Stick upright and supported until the dry ice and alcohol
is evaporated. This will end the cooling cycle and the Quick Stick will
return to room temperature.
Caution: The plastic outer covering can become very brittle and cold dur-
ing use.
8.
Place the cell into the maintenance bath. The mantle must be freed prior
to use. For highest accuracy, the cell must anneal by keeping it in the
bath for about 24 hours prior to use.
4 Freezing Process
11
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