Abstract: A device and a method for measuring the mass loss rate of a sample of combustible material placed on a mass-sensitive platform. The material has been formed into a block through which a heating wire has been inserted that thermally degrades the block when an electric current is passed through the embedded wire. Because the terminal ends of the embedded wire deform when heated, attachments that supply the current to these terminals exert spurious forces on the block resulting in inaccurate mass measurements. To eliminate these forces, the terminal ends of the heating wire are connected to high conductivity leads that are dipped into electrically insulated reservoirs of a conductive fluid, typically mercury, to which a power supply provides a potential difference. As the terminal ends of the heating wire deform under the resulting current, the leads are free to move in the conductive fluid without exerting any forces on the block, allowing the true mass loss rate of the sample to be measured.

Abstract: 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 CO.sub.2 snow and an aerosol of HFC-23 that are "thrown" by the remaining gaseous CO.sub.2 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.