What type of extinguishers have the expelling gas and extinguishing agent mixed in the same tank?

Stored pressure extinguishers have the expelling gas and the extinguishing agent mixed in the same tank, allowing for efficient and immediate release of the agent when activated. In these extinguishers, an agent like water, foam, or dry chemical is kept under pressure, which means that when the trigger is pulled, both the agent and the expellant gas are released simultaneously. This design allows for a consistent discharge of the extinguishing agent, ensuring that fires can be addressed quickly and effectively.

Other types of extinguishers, such as foam extinguishers and spray extinguishers, may utilize a different mechanism, often employing a separate source of propellant or different methods for mixing their components. Water mist extinguishers specifically utilize a fine mist of water, which may involve separate pressurization and does not inherently mix the agent and the gas in the same way as stored pressure extinguishers.