Patent ID: 7544226

Claim:
A grille member comprising: a body adapted to support formation of an air current rotating around the body; and a plurality of air passages formed at the body to guide the rotating current into the body, each of the air passages having a leading surface generally facing into a flow direction of the rotating current and a tail surface upstream from the leading surface relative to the flow direction; wherein the body is adapted to allow air to draw in the rotating current so that the rotating current, when passing over each of the air passages, first reaches a start of the tail surface and ends at a start of the leading surface; wherein each of the air passages is formed so that at least one plane extending along the tail surface and a line along the flow direction of the rotating current meet at an obtuse angle at an upstream side of the flow direction of the rotating current; and wherein the tail surface comprises first and second faces formed so that the planes of the first and the second faces and the line along the flow direction of the rotating current meet respectively at first and second angles, each of which is an obtuse angle, at the upstream side of the flow direction of the rotating current.