Centrifugal fan spiral housing - has welded end walls centralising housing mantle by retaining it on at least two sides

摘要

Spiral housing for a centrifugal fan comprises a spiral mantel scroll (2) to which the two end walls (3) are secured by welding. The edge of the side wall engaging the scroll is shaped so as to centralise this scroll, the edge of the scroll being held in, and retained by, the side wall at at least two sides. The wall may, for this purpose, be shaped to form a Z-like profile, having an outer portion (6) parallel to and in contact with, the outside of the scroll (2), an inwardly bent portion (7) gripping round the scroll edge and including an angle of 25 deg. to 65 deg. with the outer portion (6), followed by an outwardly bent portion (8) leading into the side wall (3) proper.