Abstract: The whirlpool tub includes a rigid tub shell inserted into the opening of a surrounding podium. The tub is to be filled with hot water. A first insulation membrane is installed spacedly around the tub inside the podium, defining a first closed air pocket between the tub and this first insulation membrane. A second insulation membrane is installed spacedly around the first insulation membrane, also inside the podium, defining a second closed air pocket between the first and the second membranes. The first membrane is punctured and hangs loosely from the podium structure, thus allowing limited air circulation between the first and second air pockets. Consequently, positive condensation control is accomplished, preventing same from occurring, in addition to providing thermal and acoustic insulation to the tub. The first membrane comprises an inner reflective metallic foil fixedly mounted on a synthetic felt backing. The second membrane is a mineral wool blanket.

Abstract: A sound absorbing substrate for use as an underlayer in a flooring structure including a subfloor. The substrate is made of a resilient material and more particularly of recycled tires and comprises a bottom surface sized to cover a given surface area. This bottom surface is provided with cavities that preferably consist of parallel grooves extending at an angle of about 45° with respect to one side edge of the substrate. These cavities leave a portion only of the bottom surface in contact with the subfloor. The surface ratio of the portion of bottom surface in contact with the subfloor to the given surface area covered by the bottom surface ranges from 20 to 65%. Such substrates can be of reduced thickness while still having good sound absorbing properties.

Abstract: In a multiblower system for cooling electronic components, each blower has a backflow preventor. The backflow preventor has two pieces of flexible material and a screen attached to the intake side of the blower assembly. Each of the pieces of flexible material is scored through to form a petaled opening through which air may pass. The scores on one of the pieces of flexible material are out of alignment with the scores on the other piece when assembled together in the blower assembly. When the blower is running, the petals in the pieces of flexible material open to allow air to pass through the blower assembly. When the blower is stopped, the petals are closed against the screen due to the pressure differential between the inside of the enclosure and the outside of the enclosure caused by the effect of the draw of the other blowers in the system.

Abstract: An acoustic construction panel for use in the construction of walls, floors, or ceiling structures to improve the acoustical properties thereof, and a method of making that panel. The panel comprises a composition of natural wood fibers, paper and starch, and is absent of any chemical toxic products. The panel has a minimum thickness of about 3/4-inch, and an average density in the range of from about 15-lb/ft.sup.3 to 17-lb/ft.sup.3. A plurality of cavities are perforated on one surface of the panel to increase the acoustical surface properties of the panel. In the construction of the panel the wood pulp is directed into a holding tank for a predetermined period of time in order to expand the wood fibers, and further in which a composite mixture is produced by introducing into the wood pulp predetermined quantitites of starch and wax.