Abstract: An extremely efficient, substantially noiseless portable fan suitable for household use is provided which produces a highly focused, homogeneous stream of substantially laminar flow air to achieve effective air movement and cooling throughout an entire room. The fan includes a torus-shaped shroud, the intake portion of which has aerodynamic configuration having a precisely engineered geometry to minimize turbulence and promote laminar flow. The shroud intake portion includes an exterior angled Venturi surface, which extends toward the shroud intake orifice, to intersect with a radiused edge which joins the Venturi surface with an interior aerodynamic surface. An impeller assembly including a central bullet-shaped nose cone and a plurality of aerodynamically-configured radial blades are mounted within the shroud to further minimize turbulence and promote smooth air flow.

Abstract: A simple two-piece reusable plastic whistle which, when installed in an air filter, emits a shrill tone to signal a predetermined clogged condition of the filter at which time the filter should be cleaned or replaced.

Abstract: A heating vent is disclosed in which a T-shaped housing of light weight sheet metal is inserted in the plastic vent hose of an electric clothes dryer to provide passages through which the dryer is vented either outdoors through the vent hose or indoors through a sock-like filter having its open end stretched over the lateral outlet of the housing according to whether a pivoted valve member in the housing is in its summer or winter position.

Abstract: A heating vent is disclosed in which A T-shaped housing of light weight sheet metal is inserted in the plastic vent hose of an electric clothes dryer to provide passages through which the dryer is vented either outdoors through the vent hose or indoors through a sock-like filter having its open end stretched over the lateral outlet of the housing according to whether a pivoted valve member in the housing is in its summer or winter position.