Patent attributes
A method and an apparatus for preventing freezing at the outlet of a fire extinguisher are disclosed. Moisture in the fire extinguisher fluid is removed by contacting the fluid in the fire extinguisher bottle with a desiccant such as molecular sieve 3A. After the fluid in the extinguisher has been in contact with the desiccant for a week, the moisture level is about 5 ppm, well below the 40 ppm which causes freezeup at the outlet. The desiccant is preferably placed inside a metal screen tube having metal wire loops extending from the sides of the mesh tube. The wire loops keep the mesh tube away from the outlet so that flow restriction will not occur. The wire loops also protect the desiccant from being damaged when the fire extinguisher is discharged and provide a handle which can be used to pull the metal screen tube out of the bottle during refurbishment.
