Abstract: A centrifugal fan with a noise suppressing arrangement includes a fan, a motor for rotating the fan and a scroll casing for accommodating the fan, the scroll casing is formed of a first scroll casing member covering the fan and a second scroll casing member forming the bottom part of the scroll casing, the second scroll casing member being provided with at the center thereof a cylindrical housing for holding the electric motor, and further includes a porous sound absorbing member having elasticity sandwiched and secured between the first scroll casing member and the second scroll casing member whereby the combination of the porous sound absorbing member and an air layer formed between the porous sound absorbing member and the inner bottom wall of the second scroll casing member suppresses noises caused by rotation of the fan.

Abstract: An aluminum lining in combination with a sound absorbing object such as a fleece and for protection against thermal load, has a double corrugated contour resulting in pyramids and being perforated in specific locations such as the peaks, along the edges of both.

Abstract: An interlayer for use in sound-insulating laminated glasses which is in the form of a laminated film of two kinds of resin films (A) and (B), each comprising a polyvinyl acetal acetalized with an aldehyde having 6 to 10 carbon atoms for the film (A) or with an aldehyde having 1 to 4 carbon atoms for the film (B), or is in the form of a resin film (C) comprising a mixture of the two kinds of polyvinyl acetal resins. The interlayer mitigates the coincidence effect to prevent the reduction of TL value without impairing the basic characteristics required of laminated glasses thereby permitting the interlayer to exhibit outstanding sound-insulating properties over a wide temperature range for a prolonged period of time.

Abstract: A sound-absorbing multi-layer structure is disclosed comprising a structural part which is capable of oscillating and a loosely engaging damping sheet, which sheet comprises a flexible material and high material absorption factor and is made up of a heavy sheet with a viscoelastic support layer tightly connected thereto. The support layer comprises a plurality of angularly constructed support elements which are shaped and arranged so that together with the structure which can oscillate and the flexible heavy sheet they form a coherent labyrinth of hollow spaces with acoustically effective cavities.

Abstract: An electromagnetic induction apparatus includes a tank having a bottom plate and containing an electrical device which vibrates during operation. The tank is supported by supporting members disposed between the tank bottom plate and a floor surface to define spaces therebetween. Sound suppressing members are disposed in the spaces defined between the support members, the tank bottom plate, and the floor surface. The sound suppressing members absorb sounds generated within the spaces and prevent air within the spaces from resonating during vibration of the electrical device.

Abstract: A knitted fabric panel structure has first and second spaced apart knitted layers and an intermediate spacing knit of ribs interconnecting the layers, the ribs of the spacing unit being of an industrial yarn of aramide fiber, carbon fiber, ceramic fiber, fiberglass, or blends of such fibers. The spacing knit is impregnated with a hardened resin such that the intermediate ribs form rigid spacing elements of the first and second layers.

Abstract: An air-borne sound insulating arrangement with absorption properties for surface elements, in particular for partition walls in motor vehicles, comprises a heavy layer which has foam layers on both sides which have skins on the outside or have a foil as a covering. The arrangement is arranged so close to the surface element (sheet 1) to be protected that the distance between the heavy layer and the surface element is as small as possible. Adhesion to the surface element does not take place. The arrangement can rest against the surface element or can be at a short distance therefrom so as to even out corrugations or the like. The arrangement is arranged in the desired position in relation to the surface element by means of fastening bolts and/or fastenings at the edges.

Abstract: An acoustical panel comprises a compressed and cured mass of binder impregnated randomly oriented and interentangled fibrous glass bundles. The acoustical panel surprisingly is characterized by high sound absorption coefficients at low frequencies.

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.

Abstract: The present invention concerns a method of preparing a porous structural unit comprising a plurality of layers having different specific gravities by pressing and heating a material including resin particles between opposing molds having a temperature difference to thereby cause the fusion or bonding of the resin particles, and a porous structural unit which improves acoustic absorption properties and heat insulation properties and in which the specific gravity is continuously changed.

Abstract: A sound-absorption material for an automobile includes a damping material, a sound-absorption material and a surface material. The damping, sound-absorption and surface materials are integrated together. The damping material includes a moldable plastic constraining material and an adhesive damping sheet containing a petroleum resin. The sound-proof material is integrally attachable to an automotive sheet material such as a dashboard.

Abstract: A mass and spring system for soundproofing, particularly in vehicles, comprises a bending-soft heavy plastic layer as the mass and a soft layer as the spring, which is applied to the sound radiating surface or wall and which is a gel of 10 to 50% by weight of an organic polymer or silicone polymer and 50 to 90% by weight of a plasticizer compatible therewith, which at room temperature has a modulus of elasticity E'.ltoreq.5.times.10.sup.5 Pa and an internal loss factor d.gtoreq.0.5.

Abstract: A process for preparing a wholly carbonaceous integrated diaphragm for acoustic equipment use comprises blending under application of high shearing force a mixture of one or more kinds of organic high polymeric substances carbonizable on baking and powder of graphite with crystals high elastic modulus developed therein; extrusion-molding the uniformly blended and dispersed mixture through a profile extrusion die to give a core material with orientation along the direction of the extrusion and to be cut to a desired form; independently blending and sheeting under application of high shearing force the mixture with the organic powder oriented to high degree parallel to the direction of the surface of the sheet and further passing the sheet through a calendering roll to give a skin material in the form of a film or sheet; bonding said skin material on both sides of the core material by the use of such organic liquid composition that provides high yield of carbon residue on baking and then baking the resulting un

Abstract: A rigid, self-supporting, acoustical mineral fiberboard comprising a mixture of about 50 to 70 weight percent of mineral fibers, 15 to 35 weight percent of perlite, 1 to 10 weight percent of cellulosic fibers, and 4 to 15 weight percent of a binder with the proviso that the board forming solids do not include any clay filler. A pattern is formed on the fiberboard after the fiberboard has been dried.

Abstract: A composite molded article made of a nonwoven fibrous mat wherein inorganic monofilaments having a length of 10 to 200 mm and a diameter of 2 to 30 micrometers are partially bonded with a thermoplastic resin binder, may voids being provided throughout the mat and a large number of fine holes communicating with the voids in the inside being formed in at least one surface of the mat; and processes for producing the same.

Abstract: A woven fabric structure impregnated with a hardened resin has first and second warp fabric sections, the second section comprising a plurality of pleats integrally joined to the first section by warp threads of the second section and interwoven with the weft threads of the first section. The fabric is of an industrial yarn such as aramide fiber, carbon fiber, ceramic fiber, glass fiber or a blend of such fibers.

Abstract: A sound- and/or vibration-damping coating, which comprises a layer of a relatively hard substance (2) having pores, interstices, cavities (3) and/or hollows (12) containing a material (4) which has a higher plasticity or elasticity than said substance (2), and an element provided with said coating. This coating may be applied on said element by applying to the surface of the latter a surface treatment ensuring the adhesion of the layer of relatively hard substance (2), by applying this layer to the so treated surface by projection of said substance in the at least molten state and as droplets, by using known per se techniques, and by entering said material (4) into cavities (3) formed between coagulated droplets of said substance (2).

Abstract: An acoustic panel having highly desirable sound absorption characteristics. The panel is preferably formed of an open frame, there being at least one septum centrally located within the frame opening and in contact with the frame members. On each side of the septum are expanded fiberglass batts. Both sides of the frame are faced with perforated hardboard sheets which, in turn, are covered by an open-cell foam layer and a layer of scrim material comprising metal foil and a tear-resistant backing. The panels can be covered with a decorative fascia such as fabric or synthetic sheet materials.

Abstract: A laminate acoustic window for sonar systems having a pair of septa sandwiching a core therebetween, the core being made of a low shear high elongation to break material, the septa being formed of a relatively low density, high modulus material. The windows of the invention are characterizied by unusual freedom from attenuation loss over a wide frequency range. The windows are further substantially self damping and avoid thereby a generation of significant quantities of deleterious noise due to self generated vibration and transmitted vibration.

Abstract: The structural element contains a first sound-absorbing and thermally insulating layer (21) and a second sound-insulating, dimensionally stable supporting layer (23). Preferably, the first layer consists of a thermoformed fibre mat or a foam which is at least partially open-cell, and the second layer consists of a rigid, thermoformed synthetic material, for example a plastic material reinforced with glass fibres. A porous or microporous decorative layer (22) can be applied to the outside of the first layer and a thermoformed carpet (24) can be applied to the outside of the supporting layer. A heat-sealable adhesive layer (27) can be placed between the two layers, the said adhesive layer incrasing the bond between the two layers.

Abstract: A sound absorbing panel structure is formed of a panel of sound absorbing material, such as a felt mat or fiberglass mat, and spaced apart, parallel strips of a decorative non-sound absorbing material attached to one side surface of the sound absorbing panel so that the sound absorbing panel is exposed in the area between the adjacent strips of decorative material.

Abstract: A multilayered composite having improved flammability and smoke resistance properties comprising:(a) a flame retardant flexible polyimide film facing layer,(b) a first high temperature resistance silicone adhesive layer bonded to the polyimide film facing layer,(c) a first open cell polyimide foam layer bonded to the first adhesive layer,(d) a second high temperature resistance silicone adhesive layer bonded to the first open cell polyimide flame layer,(e) a fire retardant flexible silicone sheet rubber layer bonded to the second adhesive layer,(f) a third high temperature resistant silicone adhesive layer bonded to the silicone sheet rubber layer, and(g) a second open cell polyimide foam layer bonded to the third adhesive layer.

Abstract: A self-supporting sound barrier for the operator's cover of a construction type vehicle is supported within the operator's cover at the perimeter of the sound barrier only and is self-supporting throughout the major surface area of the sound barrier. The sound barrier has strengthening and supporting materials, such as a grid structure or oriented fibers, throughout the main body of the sound barrier which lengthen during sagging of the sound barrier. As the grid sturcture lengthens, it contacts portions of the operator's cover and the sound barrier is restrained from further sagging. Prior art sound barries utilize an elaborate system of parts and assembly procedures to secure a sound barrier in place within an operator's cover. The subject self-supporting sound barrier is simple to manufacture and is easy to install and/or remove from an operator's cover.

Abstract: The present invention relates to a novel sound attenuating laminate. More particularly, the invention relates to a simpler, lighter, and more effective noise attenuating laminate which is made up of seven layers of material. The laminate includes a duct liner, a moisture barrier, a first protecting layer, a screen, acoustic attenuating material, a second protecting layer, and a solid backing sheet. The laminate is readily incorporated into various sections of a jet engine compartment in order to attenuate the sound produced by the jet engine. Hollow rivets are used to conduct acoustical energy to the intermediary layers of the noise attenuating laminate.

Abstract: A vibration-controlling member is made by containing a flake-shaped powdery substance having vibration controlling action in a retainer adhered to one surface of a surface sheet. Any external shock imparted to the member is subjected to the vibration controlling action due to a grain boundary friction of the powdery substance.

Abstract: A post and panel wall system for use as sound barriers and the like utilizes a precast post which is disposed upon a foundation having a tensioning cable extending upwardly therefrom and recesses into which depending anchoring rods on the posts are placed. The tensioning cable is tensioned and then the recesses in the foundation are filled with a cementitious mixture or grout to thoroughly bond the anchoring rods into the foundation. The posts have channels in which the vertical edges of the wall panels are seated, and desirably the wall panels have reduced thickness end portions with arcuate edges to permit some adjustment within the channels. The posts and panels may be erected seriatim, or the posts may initially erected and the panels then lowered into place.

Abstract: An acoustic insulating board of foam with structured bulge-forming surface in the form of regions (I, II) of different thickness. In order to obtain differing acoustic efficiency, the acoustic insulating board comprises plurality of individual boards (1) arranged one above the other, which boards are compressed in the regions (I) of lesser thickness and are fused together on their surface. In the regions (II) of larger thickness, the boards lie loosely on one another so that a top side facing in the direction of the structural bulging of a central individual board (1) is profiled in the regions of greater thickness.

Abstract: A method of manufacture of a foam core board is described as well as vehicle trim panels made from such board. A foam board having a cell structure including a structure with large cells in a center portion is initially formed. This board is skived into two separate panels, each having one surface with relatively large cell structure and wherein said cells have been opened by the skiving process. This surface acts to promote enhanced sound absorption from the foam core board. This board may be laminated with appropriate decorative material and molded to make contoured resilient vehicle trim panels.

Abstract: Acoustic damping is provided by a dimensionally-recoverable article, either in single layer or constrained-layer form. The single layer, or the damping layer of a constrained-layer article, comprises a mixture of a damping component (generally having a high tangent delta value) and a hold-out component (generally having a significant crystallinity).

Abstract: A moldable fibrous composite having thermal and acoustical insulating characteristics and methods of production thereof are provided. The composite structure comprises a substrate, a middle layer and a non-woven top layer. The substrate may be in the form of a fibrous web or, alternatively, a thermoplastic film. The middle layer comprises mineral fibers of a sufficiently short length to substantially preclude interlocking of any of the mineral fibers with other fibers of the structure and to provide the structure with desired flexibility. The mineral fibers are present in a quantity sufficient to impart desired heat and sound insulating properties to the structure. The top layer may be made of organic fibers or a substantially uniform mixture of organic and inorganic fibers. In making the invention composite structure, the middle layer and the top layer are introduced onto the substrate, respectively. The three layers are thereafter consolidated, such as through needle punching.

Abstract: Thermoformable laminates, suitable for use as automobile headliners, comprising a layer of non-woven fabric (acoustical pad bonded to one side of a foamed polymer sheet are disclosed. The non-woven fabric comprises a certain blend of staple fibers which provide an optimum balance of characteristics including cost and improved sound absorption characteristics which are important headliner characteristics, especially, for compact and subcompact automobile uses.

Abstract: A nonwoven composite fibrous material adaptable as an insulation medium is formed by a loose layer of inorganic fibers, such as rock wool, glass, ceramic, carbon-graphite or the like, bonded together by at least one carrier web layer positioned on a surface of the inorganic fibrous layer. The carrier web layer is a blend of inorganic fibers and organic fibers with the organic fibers comprising about 1% or less by weight of the total nonwoven composite fibrous material. Both organic and inorganic fibers of the carrier web are advanced into interlocking relation with the fibers of the inorganic layer by needle punching the carrier web.

Abstract: A protective suit against sound waves with which it is possible to achieve a considerable reduction of the effects of sound waves on the human body. The suit material is furnished with at least two flexible soundproofing layers, of which at least one layer increases the weight per unit area of the suit, and another acts as a cushioning layer.

Abstract: A combination skid resistant and vibration dampening device formed from rubber-like material having a high coefficient of friction which is integrally bonded to cellular foam type material which has high impact absorption capacity.

Abstract: Nylon impression fabric is used as a cover fabric for an acoustical material (e.g., 1 inch thick polyester foam) substrate in an environment--such as a textile workplace environment having textile machinery such as texturing air jets--to provide for good sound absorption while being easily cleanable, and having other desirable properties that lead to significant high frequency (e.g., 4000-20000 Hz) noise reduction over long periods of time. The substrate and fabric combination has an HFNRC (high frequency noise reduction coefficient) of at least about 0.80. The facing fabric has a fractional cover factor of about 0.80, a coefficient of friction of less than about 0.30, an air porosity of about 10-50 cfm, and a Taber abrasion resistance of greater than about 400 cycles. The facing fabric preferably is uncoated, and is not full surface bonded to the substrate (e.g., either wrapped or point bonded).

Abstract: A noise silencer for highway is adapted to be stuffed in a joint gap formed in a highway. It has a rectangular casing and padding enclosed in the casing. The casing is provided with a vent hole adapted to be closed by a plug. Before mounting the noise silencer, air is firstly sucked out from the silencer through the vent hole to flatten the padding and the vent hole is plugged. After the silencer has been mounted, the vent hole is open to inflate the padding so that the silencer will be pressed against the opposite walls of the joint gap.

Abstract: A volumetric sound absorber for audible sound frequencies is made from a thin sheet material that is permeable to air with thickness mass, and flow resistance within specified ranges.

Abstract: An acoustic tile that provides soundproofing in a modular wall, such as is used in a modular panel office system, comprises a rigid rectangular metallic frame, a septum formed of a calcium carbonate-filled molded synthetic rubber polymer, a layer of low-density fiberglass and a layer of high-density fiberglass. The front of the frame is covered by fabric, and the back of the frame has fittings to attach the acoustic tile to a wall panel.

Abstract: A perforated panel having a thickness of at least about 6 mm, for use as a sound absorbing element, especially at lacunarias. Each perforation is covered by a thin fiber cloth which is bonded to the edges of the perforation, rendering said panel element a specific acoustic flow resistance of between 1200 and 4000 Nsm.sup.-3.

Abstract: A porous metallic material of the present invention is constructed of a laminate consisting of an expanded metal and a fibrous metallic fiber both of which are pressed to be joined to each other under pressure. This porous metallic material is excellent in bending strength and workability. The porous metallic materials may be laminated to a honeycomb structural element and a rigid plate so as to form a porous structural material. To this porous metallic material may be also laminated a decorative layer so as to form a porous decorative sound absorbing material. The present invention provides the above-mentioned products and method for manufacturing the same.

Abstract: The invention relates to an adhesive insulating system (3) that is non-destructively removable, e.g. for repair purposes, for sound insulation of partition walls (1), particularly in motor vehicles. Between the foundation and the overlying layers of the insulating system (3) a layer (2) of a highly under-cross-linked polyurethane material or a special bitumen mixture is applied that has a strong adhesive effect and thus enables a force-locked connection to be made between the foundation (1) and the insulating system (3). To ensure that the desired flexibility is obtained together with unchanged acoustic effectiveness even when a carpet (8) is laid on the insulating system (3) or its heavy layer (6), according to the invention a decoupler (7) of soft elastic, predominantly open-pored material is arranged between the carpet (8) and the heavy layer (6). Surprisingly, along with the desired flexibility, the acoustic effect is further improved.

Abstract: A soundproof structure for vehicle use includes a vehicle body forming panel, a lower side sound absorbing foamed resin layer on the panel, a rigid sound insulating panel on the foamed resin layer, and a press means between the vehicle body forming panel and the sound insulating panel to urge the sound insulating panel toward the former panel, the press means acting to hold the lower side foamed resin layer in compressed state, and an upper side sound absorbing layer being further laminated on the sound insulating panel.

Abstract: The covering is immersed in water (2). A viscoelastic substance (4) is disposed in ducts formed by rigid auxiliary walls (5) fixed to the base wall (1). The ends of these ducts (6) contain air. The invention is applicable, in particular, to providing protection against under-sea noise.

Abstract: The invention provides a self-supporting frame resistant composite material comprising at least one layer of lead material and at least one layer of flame resistant fibrous material, the layers having been bonded together, e.g., mechanically as by needling, to provide a self-supporting structure.

Abstract: A sound-absorbing panel includes a synthetic foam mat having a given size, a synthetic fiber web having substantially the given size, a first attachment for attaching the synthetic foam mat to the synthetic fiber web at least pointwise, and a second attachment for attaching the sound-absorbing panel to a wall for damping sound radiation of the wall while maintaining a distance between the sound-absorbing panel and the wall.

Abstract: An acoustical barrier usable for sound deadening and vibration dampening in vehicles which includes a base layer of a flexible foam secured at the outer surface to an insulation layer of polyurethane elastomer molded to the shape of the area to be insulated such as an automobile fire wall area. The inner surface of the base layer will preferably be in contact with the area to be insulated. The polyurethane elastomer of the insulation layer will preferably include a natural mineral filler impregnated therein. The insulating layer provides the rigid form for holding of the flexible foam, which itself provides a stand-off to hold the insulating layer in spaced relation with respect to the vibrating surface. The polyurethane elastomer can vary in thickness in proportion to the level of acoustical activity of the area to be insulated.

Abstract: A light viscoelastic damping structure has a plurality of damping strips widely separated on the surface of a lightweight panel. The strips may be arranged parallel or at right angles to each other. Each damping strip includes a viscoelastic damping layer, a first honeycomb structure having opposing face sheets and attached to one surface of the damping layer, and a second honeycomb structure having face sheets on opposing sides thereof attached to the damping layer and to the panel.

Abstract: A sonar dome having an external wall in which a central layer is formed by a plurality of woven webs of glass fibers impregnated with a resin and by two peripheral layers located on each side of the central layer, the peripheral layers being constituted by a plurality of woven webs of carbon fibers impregnated with a resin.

Abstract: A multi-tubular acoustic absorber panel system suited particularly for use in open office environments or workspaces with unwanted echoes, excessive noise, or the need for enhanced acoustic privacy. The basic components of the system are a series of sound absorbent tubular members and a structure for holding the members in an array, creating a baffle which can be attached to wall or ceiling surfaces or, in the preferred embodiment, to a manufactured office partition. When installed, the system creates a lightweight, adaptable, highly absorbent enclosure, capable of significant reduction in unwanted noise and increase in acoustic privacy.

Abstract: The invention relates to an adhesive insulating system that is non-destructively removable, e.g. for the purpose of repair, for sound insulation of partition walls, particularly in motor vehicles. To overcome the disadvantages associated with the previous systems in mounting and also in repair a layer of material of a highly under-cross-linked polyurethane is now applied between the substrate and the overlying layers. This polyurethane layer has, owing to its under-cross-linking, a great adhesive effect and thus enables the substrate and the insulating layers to be joined in a force-locked manner. The adhesive material layer can be prefabricated or is prepared by spraying on a highly under-cross-linked 2-component mixture of the polyurethane former.