Foam generating apparatus and method for compressed air foam systems

摘要

An apparatus for generating foam for use in a compressed air foam system (CAFS) incorporates two plates housed in a chamber. A surfactant solution enters the chamber through an orifice in one plate. Pressurized air enters the chamber through a number of channels bored through the other plate, the channels appearing in an annular groove which circumscribes the solution inlet. The restricted area between the plates balances the pressure between the incoming solution and air by achieving an equilibrium at some particular radius out from the center of the two plates. A liquid, such as water or a surfactant and water solution, may optionally be introduced through an inlet into the chamber. The resulting mixture is fed through a main outlet positioned along the chamber wall.

主权项

1. An apparatus for generating foam in a compressed air foam system (CAFS), the apparatus comprising:
(a) a chamber comprising a chamber wall; (b) a first plate positioned within the chamber; (c) a solution inlet passing through the chamber wall and the first plate; (d) a second plate positioned within the chamber and parallel to the first plate, wherein a restricted area is formed between the first and second plates, and wherein the second plate comprises a second plate center and a plurality of air nozzles each positioned radially outward from the second plate center; (e) an air inlet passing through the chamber wall; (f) an air passage connecting the air inlet and the plurality of air nozzles, wherein the air passage comprises an open, cylindrically-shaped air manifold formed by an annular air manifold wall extending from the second plate to the chamber wall and forming an entirely open space between the second plate and the chamber wall and within the air manifold wall, wherein the annular air manifold wall comprises an air manifold wall outer diameter equal to a diameter of the second plate all along the air manifold wall outer diameter, and wherein the air manifold directly connects the air inlet to the plurality of air nozzles whereby air may travel from the air inlet out through the plurality of air nozzles; (g) a main inlet passing through the chamber wall, wherein the main inlet is positioned to deliver a liquid into the chamber; and (h) a main outlet passing through the chamber wall;wherein the chamber comprises a minimum chamber cross-sectional area measured perpendicular to at least one of the main inlet or the main outlet, the main inlet comprises an inlet cross-sectional area, and the main outlet comprises an outlet cross-sectional area, wherein the minimum chamber cross-sectional area is at least as large as the inlet cross-sectional area the outlet cross-sectional area.