Airflow adaptor for a breath-actuated dry powder inhaler

摘要

A breath-actuated dry powder inhaler, comprising an airflow adaptor and a swirl chamber. The swirl chamber is configured to combine at least two breath-actuated airflows for entraining a dry powder from the inhaler. The swirl chamber extends along a longitudinal axis from a first end to a second end. The first end has a plurality of inlet ports and the second end has an outlet port in fluid communication with the airflow adaptor. The plurality of inlet ports at the first end of the swirl chamber are disposed in a manner such that a first breath actuated airflow is directed from the first end to the second end in a longitudinal direction. A second breath actuated airflow is directed in a substantially transverse direction into the first end of the swirl chamber such that the at least two breath-actuated airflows collide and substantially combine. The swirl chamber has a plurality of vanes non-rotationally fixedly attached to the first end of the chamber. The vanes extend at least in part radially outwardly from a longitudinal axis of the chamber. Each of the vanes has an oblique surface facing at least in part in a direction transverse to the axis such that a first portion of the combined airflow is deflected in a substantially longitudinal direction towards the second end of the chamber to the outlet port for delivering the combined airflow to an airflow adaptor. The inhaler is characterised by a swirl chamber by-pass port configured to allow a further breath-actuated airflow from a proximal end of the airflow adaptor to a distal end of the airflow adaptor independently of the swirl chamber when a breath-induced low pressure is applied to the distal end of the airflow adaptor.