Abstract: A multiple impeller flow inducing device in which driver coils are intermittently energized in timed relation to rotation of the impellers to interact with permanently magnetized portions of the impeller to rotate the same. The impellers can be rotated in opposite directions or in the same direction. A two section impeller construction allows each section to be magnetized in opposite pole orientation and when assembled creating alternate pole orientations of successive portions, arcuate segments forming a shroud or the type of blades can be magnetized to provide the impeller magnetized portions. Stator guide vanes can be interposed between successive impellers.

Abstract: A DC driven fan with blades made of magnetized material and permanently magnetized in the radial direction and cooperating with a plurality of electromagnetic stator coils mounted external to the outer fan edges. Adjacent blades have alternate N-S, S-N radial magnetic orientations. In one embodiment, the blades are mounted in a non-ferrous hub and in an alternate embodiment they are mounted in a ferrous hub so that adjacent blades function like a U or V-shaped magnet. Blades can be made of magnetized ferrous, ferromagnetic, or magnetized plastic depending upon the application and blade strength specifications.

Abstract: A motor drives a hub having axially extending blind tapered recesses to receive tapered shoes on a plurality of blades, and threads which fasten a ring that presses the shoes axially into the recesses have a hand-direction that tend to tighten in response to the rotation of the shaft. The recess is partially defined by a forward downward sloping upper wall. The shoe includes a forward downward upper surface. The recess sloping wall functions as a positive stop for seating the shoe by engaging the sloping shoe surface and as a centrifugal force absorbing wall during rotation of the blades.

Abstract: A closure device for access openings having a face plate attractively complementing the surface in which said opening occurs and manufally driven spring biased latching mechanisms for securing the device in closing relationship to such opening. Optional gasket means and insulative batt enhance the versatility of the device.

Abstract: Means and methods for maintaining laboratory work stations which have essentially open work areas, free of noxious and malodorous air contaminants by the use of tempered induction air combined with contaminant bearing exhaust air to limit the throughput of more expensive conditioned air. The means enables both the utilization of an integral lighting unit and the efficient collection of noxious air without creating unwanted drafts and currents.

Abstract: An air outlet having a ball shaped valve member having a central passageway defined therefrom intermediated a convergent entrance and an exit, the transverse area of the entrance being at least 45% greater than the transverse area of the exit. The valve members is rotatable through 360.degree. and swayable through 60.degree.. A damper arrangement selectively actuable between a totally closed and a totally non-obstructive position relative to said passageway is described having damper actuator means and damper guide means coacting to effect a preselected location of said damper relative to said passageway in the valve member.