Abstract: Apparatus for filling beverage tanks comprising a liquid manifold and a gas manifold for counter-pressurizing the liquid as it fills the tank. Supply conduits connect the tank with the manifolds. The gas supply conduit contains a coupling device for connection to a fill-height tube on the container. This coupling device includes an optical sensor embodying a prism which reflects light from a light source when the tank has liquid below a predetermined level and directs light onto a photo-conductor. When the liquid reaches a predetermined upper level in the tank and is forced into the coupling device through the fill-height tube, the prism changes its reflective characteristics, and light passes through the prism without reflection. The change in reflective conditions is brought about by the liquid covering adjacent sides of the prism. The photo-conductor correspondingly changes an electrical signal that is utilized to operate a solenoid valve for shutting off the liquid to the tank.

Abstract: There is disclosed an improved dearator system for purging air from water. The disclosed system includes a container for containing the water, cooling means within the container for cooling the water to force air therefrom, and means for introducing carbon dioxide gas into the container to establish a positive pressure therein. The system also includes a positive pressure indicator means for indicating when the positive pressure within the container is reached. The indicator includes a housing having a bore in fluid communication with the container, a seat within the bore, and a ball within the bore. The ball is viewable through the housing and is arranged to disengage from the seat in response to positive pressure within the container to provide a readily discernible indication of positive pressure therein.