Chimney cover with diffuser and sleeve sides enclosing expansion area

摘要

A chimney cover 1 has a square section sleeve which is placed over a circular section chimney casing 103, cover 105 and flue 107. Four airways 9 are created to allow air to flow through them. The cover 1 also has a grille 11 having apertures 13 in each corner, and a diffuser cone 15 located under the grille. A reduced pressure region is created within the housing to draw emission from the chimney into the expansion area 7.