Patent ID: 7309418

Claim:
A gravity-flow water treatment filter system, comprising: a first liquid container; and a filter device in communication and below the first container, the filter device comprising a first filter component capable of providing a user with a visual indication of device exposure to at least one contaminant, said first filter component having a curved lower surface, a second filter component having an irregular upper surface and a flexible intervening porous layer therebetween substantially conforming to both the curved lower surface and the irregular upper surface to prevent significant trapping of air between the first and second filter components in order to maintain flow therethrough, wherein said flexible intervening porous layer comprises a material capable of sufficient expansion and compression to substantially conform to the curved lower surface and the irregular upper surface, wherein an average flow rate greater than 0.05 liters per minute when averaged over the passage of one liter of liquid through the filter device is achieved with a liquid head pressure of less than about 1.0 psi; and a second liquid container configured such that the second liquid container receives liquid from the first liquid container after the liquid has passed through the filter device wherein the first liquid container and the second liquid container are disposed in a pitcher or a drinking bottle.