| 摘要 |
A nozzle for producing a continuous gas/solid or gas/aerosol stream from a liquid having a high room temperature vapor pressure. The nozzle comprises a series of expansion stages, with the flow reversing direction after each expansion except the first and going over the conduit which comprised the previous expansion stage. In addition, the flow from the last expansion stage comes in contact with the inlet conduit, thereby exposing the inlet flow to the cold temperature produced in the nozzle. Since the flow in the nozzle is essentially adiabatic, the expansion in each stage takes heat from the flow in the previous stage, ultimately resulting in very low temperature flow. It is particularly useful as a fire extinguisher since it can produce solid CO2 snow and an aerosol of HFC-23 that are "thrown" by the remaining gaseous CO2 and HFC-23 at low exit velocities. This means that these agents can be used on Class A fires. A test nozzle using 1 liter (2.14 pounds) of HFC-23 demonstrated equivalency to a 2+E,fra 1/2+EE pound Halon 1211 fire extinguisher as determined by the FAA/JRC Hidden Fire Test Protocol for hand-held extinguishers.
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