Abstract: An insert is bolted to the inlet of a wood chip digester to provide air exhaust during chip loading, and over pressure relief during chip processing. The insert has an upper flange which connects to an overhead chip valve, and a lower flange which mates with the top of the digester inlet. The insert has an outer cylindrical section extending between the upper flange and the lower flange and a lower conical section which extends downwardly into the digester. An inner cylindrical sleeve is positioned coaxially with, and joined to, the outer wall by a conical ring at the top, and is joined to the conical section at the bottom. The outer wall, the conical section, and the inner cylindrical sleeve form a sealed volume, which maybe partitioned into two parts. The first part has a sector between the outer wall and the inner cylindrical sleeve which is connected to a pressure relief fitting, a portion of the sector being porous for allowing pressure relief through the fitting.