Propellantless foam dispenser

摘要

A propellantless foam dispenser comprising a container which has a flexible outer wall and contains a foamable liquid and air. The container has an outlet opening which is disposed at the top of the container and has a foam discharge nozzle associated with it. A foam generator is associated with the outlet opening and comprises a body that includes a bottom member and a shell member and contains a porous element which covers the air inlet opening of the foam discharge nozzle. The bottom member of the foam generator body is formed with liquid passage openings and with an air passage opening. A tubular air line is provided which communicates with the air passage opening and extends into the interior of the container close to the base of the container. A mixing chamber is provided between the bottom member of the body of the foam generator and the porous element which comprises a sieve disc. The sieve disc is contained in and defines a radial clearance with the shell member of the body of the foam generator and is axially displaceable in the shell member under a superatmospheric pressure in the container whereby it is urged to a first end position whereat the disc engages a peripheral flange which surrounds the inlet opening of the foam discharge nozzle. Under a subatmospheric pressure in the container, the disc is urged to a second end position which is defined by at least one stop and in which air entering the foam discharge nozzle from the outside will flow between the sieve disc and the shell member of the foam generator body into the mixing chamber and flow into the interior of the container through the air passage opening in the bottom member of the body of the foam generator and through the air line.