Powder inhaler

Claim 1

In a powder inhaler comprising a housing, having a mouthpiece opening for flow of air laden with active substance and an active substance magazine including means for incorporating the active substance or a mixture of active substance and inert components into an air stream guided through the inhaler, the housing comprising parts designed to be moveable against each other, and one housing part having an inlet opening for air; the improvement in which said inhaler includes (a) a hollow cylindrical housing comprising a lower part with a lower outer diameter and an upper part, said lower part being insertable into said upper part in an axial direction and rotatable about its longitudinal axis, (b) a cylinder for containing medication which is concentrically positioned within the lower part of the housing, said cylinder comprising an outer hollow cylinder, an inner hollow cylinder with smaller outer diameter than the inner diameter of said outer hollow cylinder, so that an annular space is formed between said outer hollow cylinder and said inner hollow cylinder in which said active substance magazine can be accommodated, the inner hollow cylinder having an internal canal for flow of air and active substance and a first passage opening to said annular space, (c) said housing having an inlet opening operatively connected with said internal canal, (d) said inner hollow cylinder having an upper end, and, at said upper end, second passage openings operatively connected with said internal canal for flow of air laden with active substance, (e) means comprising a cyclone chamber operatively connected to said passage openings, (f means providing an exit opening from said cyclone chamber, (g) means permitting axial displacement and/or rotation of the active substance magazine about its longitudinal axis, said magazine having a plurality of apertures for receiving individual doses of medication, whereby axial displacement and/or rotation of said magazine aligns successive apertures with said passage opening to said internal canal, and (h) means providing a channel for flow of air from said inlet opening to the outer wall of the outer hollow cylinder and through said outer hollow cylinder to a position in alignment with said first passage opening whereby a first air stream flows from said inlet opening through said internal canal and a second air stream expels a single dose of medication from one of said apertures, through said passage opening, into said internal canal.