Patent ID: 7377405

Claim:
In combination, an enclosed liquid containing reservoir, a pump and a vacuum relief device, the reservoir having a dispensing outlet and a liquid outlet and within which reservoir a vacuum below atmospheric pressure is developed on drawing liquid from the reservoir via the dispensing outlet, the dispensing outlet connected with the pump which is operable to draw liquid from the reservoir via the dispensing outlet, the vacuum relief device is adapted to permit atmospheric air to enter the reservoir via the liquid outlet to reduce any vacuum developed in the reservoir, the vacuum relief device comprising an enclosed chamber having an air inlet and a liquid inlet, the liquid inlet open to the chamber at a height which is below a height at which the air inlet is open to the chamber, the air inlet in communication with air at atmospheric pressure such that the chamber is at atmospheric pressure, the liquid inlet connected by via a liquid passageway with the liquid outlet, the liquid inlet at a height below a height of liquid in the reservoir such that when their is atmospheric pressure in the reservoir under gravity the liquid from the reservoir fills the liquid passageway and, via the liquid passageway, fills the chamber to a height above the height of the liquid inlet and below the height of the air inlet, and wherein when operation of the pump dispenses liquid out the dispensing outlet and creates increasing vacuum below atmospheric in the reservoir, the height of liquid in the chamber decreases until the height of liquid is below the height of the liquid inlet and the liquid inlet is open to air in the chamber such that air in the chamber flows under gravity upward through the liquid passageway to the reservoir to decrease vacuum in the reservoir.