Patent ID: 8454828

Claim:
A dispensing device for a liquid medium comprising: a reservoir having an open end; and a metering head having a first peripheral wall defining a liquid inlet sealing attached to the open end of the reservoir and a liquid outlet, the metering head including a second peripheral wall disposed within the first peripheral wall, the first and second peripheral walls defining a liquid passage extending between the open end of the reservoir and the liquid outlet, an opening extending from an exterior surface of the first peripheral wall defining a first vent passage, an annular passage disposed between the first and second peripheral walls defining a second vent passage, the second peripheral wall defining a third vent passage, the second vent passage fluidly connecting the first vent passage to the third vent passage, the third vent passage being connected to a filter unit having a first filter adjacent an interior of the reservoir and a second filter adjacent to the third vent passage, the first filter being separated from the second filter by a void space, the first filter preventing liquid from passing from the interior of the reservoir into contact with the second filter, the second filter preventing passage of bacteria from the third vent passage into the interior of the reservoir.