Patent ID: 8662355

Claim:
A refill unit for refilling a foam dispenser system that has an air compressor secured thereto and the air compressor is not disposed of with the refill unit, the refill unit comprising: a liquid pump; and a container for holding a foamable liquid connected to the liquid pump; the liquid pump including: a pump housing; a mixing chamber having an inlet check valve and an outlet check valve; the mixing chamber having an extended position with a first volume and a contracted position with a second volume; wherein movement of the mixing chamber from the contracted position to the extended position causes foamable liquid to enter the mixing chamber and movement from the extended position to the contracted position causes foamable liquid to flow out of the mixing chamber; an air inlet aperture through the pump housing configured to receive air from an air compressor that does not form part of the refill unit; an air passageway from the air inlet aperture to the mixing chamber; a sanitary seal located within the air passageway and outside of the mixing chamber for preventing liquid from passing through the air aperture in the pump housing; a foaming element located downstream of the mixing chamber; and an outlet nozzle; wherein the refill unit is configured to be received by a foam dispenser having an air compressor located therein and being configured to communicate pressurized air to the first aperture, and wherein the refill unit may be disposed of without disposing of the air compressor.