Mixing passage in a foam fire fighting nozzle

Abstract

An improved mixing passage in a foam fire fighting nozzle, the nozzle having a barrel with a first inlet to receive liquid under pressure and a second inlet to receive additive fluid and having a discharge end for discharging liquid and additive fluid. The additive fluid is communicated from the second inlet to the barrel discharge through a channel and a baffle is structured with said channel to provide a flow path for additive fluid through the baffle. The baffle cooperates with barrel wall portions to shape a relatively smooth annular liquid stream having a cross sectional area that diminishes to a minimum proximate the nozzle discharge. A mixing plate is affixed to the nozzle downstream of the baffle, the mixing plate being adapted together with the baffle to define a mixing passage in which additive distributes itself around 360.degree. and exits into a portion of the shaped liquid stream at the point of minimum cross sectional area. The improved mixing passage is accomplished by further configuring the mixing plate with at least portions of a peripheral upstream facing side outwardly angled to at least partially deflect discharging fluid in a radially outward and downstream direction.