Self venting septums for use in a liquid filtration system

摘要

A septum adapted to be pre-coated with a filter and/or chemical treatment composition is formed of a tubular core member having a top and a bottom end. A plurality of top openings is provided in the core member immediately adjacent to the top end. A short actual length portion of the tubular core is impervious adjacent to the plurality of the top opening. The balance, extending for the major portion of the length of the tubular core is perforated. A multi-layer filter screen is positioned about the exterior of the tubular core. A tubular air release shield is positioned on the filter screen having a length to substantially extend from the tubular core top to cover the top openings in the tubular core and the tubular core impervious portion. A vent opening is provided in the air release shield. An end fitting closes the top end of the tubular core. Air entrapped within the septum is vented through the tubular core top openings and the air release shield to prevent air entrapment within the septum and to augment more effective precoating of the septum.