How do portable fire extinguishers expel their contents?

Portable fire extinguishers expel their contents primarily through mechanisms that rely on manual operation or stored pressure. The most common ways include using a manual pump, which is typical in some types of extinguishers, or utilizing stored pressure to expel the firefighting agent. This method works by maintaining the agent under pressure within the cylinder, which is released when the extinguisher is activated.

In addition, some portable extinguishers employ a pressure cartridge, which further aids in propelling the extinguishing agent out of the nozzle when the extinguisher is discharged. This combination of pressure and manual activation is effective in delivering the extinguishing agent directly onto the fire, allowing the user to effectively combat various types of fires.

The other methods, such as using an electric motor or relying on a chemical reaction, are not applicable to portable extinguishers. Electric motors would require an external power source, which is not feasible for portable equipment. Chemical reactions can be responsible for some types of fire suppression systems but are not how portable extinguishers operate.