Overfill assembly made of polymeric material

Claim 1

An assembly for use with an underground liquid storage tank to control overfill of liquid during a filling operation, said assembly comprising: (a) a dump tank molded of one piece construction from a polymeric material having a reservoir portion with a bottom wall and a neck extending from the reservoir portion wherein the bottom wall of the reservoir portion has an opening to accommodate a fill tube and the neck has an opening at its top whereby access is gained to the interior of the dump tank; (b) a fill tube securely positioned in the dump tank with an upper extremity near the dump tank's neck and a lower extremity extending through the bottom wall opening; (c) piping which extends from the dump tank's reservoir portion to the fill tube; (d) a directional flow control valve associated with the piping through which overfilled liquid can flow in response to opening of the flow control valve; (e) a cover base anchor ring securely positioned in the neck of the dump tank, said anchor ring having a central opening and having a portion which extends into the neck of the dump tank and further wherein an extension of the neck encases at least that portion of the anchor ring which extends into the neck with a shrink-fit covering to ensure a liquid-tight fit between said anchor ring and neck; and (f) a removable cover for fitting over the cover base anchor ring central opening so as to close off the dump tank.