| 摘要 |
A compact, inexpensive and light-weight apparatus, for quick connection to a standard supply of liquid carbon dioxide at room temperature, includes a stiff length of tubing quickly connectable to the source of liquid carbon dioxide. This tube, in a preferred embodiment of the invention, provides all the support needed for the rest of the apparatus, which includes a manual control valve to regulate a flow of the liquid carbon dioxide, a heat exchange coil across which heat transfer takes place to cool the flow of liquid carbon dioxide, an expansion nozzle and a foraminous bag attached to the outlet of the expansion nozzle. An insulation cover is provided to surround the foraminous bag and heat exchange coil and to allow passage of gases therethrough. A portion of the liquid carbon dioxide which expands through the expansion nozzle is immediately converted into solid carbon dioxide collected at the bottom of the foraminous bag, while the rest of the liquid carbon dioxide evaporates into gaseous carbon dioxide which flows out of the foraminous bag to atmosphere. Many of the components of the apparatus are conveniently made of plastics materials for durability and low weight.
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