Patent attributes
The present invention provides an airflow control mechanism comprising a conduit for air having an inlet located at a first end thereof and an outlet located at a second end thereof; a first opening formed in a side of said conduit and able to provide a secondary inlet thereto; a movable collar at least partially surrounding said conduit at a location alignable with said first opening, such that said collar is able to at least partially occlude said first opening; further comprising a second opening beside the first opening as part of the secondary inlet, wherein the collar is also alignable with the second opening, such that the collar is able to at least partially occlude the second opening at the same time as the first opening. Thus with this airflow control mechanism, a user may select whether to occlude both the first and the second openings, in which case air will pass directly from the inlet to the outlet without any air also entering through the secondary inlet, or to occlude neither the first and second openings, in which case air entering the secondary inlet will contribute to the total amount of air exiting the outlet, or to occlude just one of the first and second openings, in which case, a fixed amount of air which is less than the secondary inlet being fully open, but more than the secondary inlet being fully closed, will enter through the secondary inlet and contribute to the total amount of air exiting the outlet. Thus the user will be provided with a highly predictable and repeatable setting for the airflow control mechanism between the fully open and fully closed positions of the secondary inlet.
