PYROTECHNIC PROPELLANT FOR NITROGEN GAS GENERATOR

In this work, pyrotechnic propellants as gas generating agents and the ir possible application in fire extinguishers are studied. Specific pr operties of the delivered combustion gases are required: high yield of gas, low burning temperature, minimal slag production, neither toxic nor highly reactive combustion products, adequate burning properties, and easy and reliable ignition. A whole range of gas generating agents (mixed with an oxidiser) are considered and some theoretical combusti on properties are calculated. Depending on the application one gas gen erating agent will be more suitable than another. Further on, we will focus on the design and the use of a gas generator in portable fire ex tinguishers for which the production of nitrogen gas or non-toxic and chemically inert exhaust gases are required. Possible gas generating a gents for this application are alkali azide based propellants. The inf luence of SiO2 and MgCO3 on KNO3-NaN3-mixtures is investigated. Propel lant characteristics are determined by experiments in closed vessel an d scale rocket engine. The developed propellant and a specifically des igned combustion chamber have been successfully used for pressurising portable fire extinguishers.