Title:
SOUND-ABSORBING PANEL FOR AIR-CONDITIONING DUCTS AND THE LIKE
United States Patent 3814208
Abstract:
A panel for the guidance of an air flow comprises a body of sheet material provided on opposite sides with mutually offset nozzles in the form of hollow bosses or perforated ribs converging outwardly. The nozzles are formed by alternately bending the sheet material in opposite directions whereby a protuberance on one side corresponds to a depression on the other.
US Patent References:
Laminated building sheet
Coffman - March 1941 - 2234517
Sound-absorbing wall covering
Boschi et al. - September 1963 - 3103255
Core structure
Robb - January 1966 - 3227598
COMPOSITE CONSTRUCTION PANEL
Ziegler - November 1969 - 3479779
ANTICLASTIC CELLULAR CORE STRUCTURE HAVING BIAXIAL RECTILINEAR TRUSS PATTERNS
Hale - August 1970 - 3525663
Laminated building sheet
Coffman - March 1941 - 2234517
Sound-absorbing wall covering
Boschi et al. - September 1963 - 3103255
Core structure
Robb - January 1966 - 3227598
COMPOSITE CONSTRUCTION PANEL
Ziegler - November 1969 - 3479779
ANTICLASTIC CELLULAR CORE STRUCTURE HAVING BIAXIAL RECTILINEAR TRUSS PATTERNS
Hale - August 1970 - 3525663
Inventors:
Morresi, Nello (3, Milan, IT)
Villa, Egidio (49, Milan, IT)
Villa, Egidio (49, Milan, IT)
Application Number:
05/216547
Publication Date:
06/04/1974
Filing Date:
01/10/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
428/132
International Classes:
E04B1/86; E04B9/04; E04C2/32; F24F13/068; E04B1/84; F24F13/06; E04B1/84; B32B3/10
Field of Search:
181/33R,33G,33GA,35R D18/2B 52/144,145 161/68,109,110,133
US Patent References:
Primary Examiner:
Wilkinson, Richard B.
Assistant Examiner:
Gonzales, John F.
Attorney, Agent or Firm:
Ross, Karl Dubno Herbert F.
Claims:
We claim
1. A panel for partly confining a fluid stream, comprising a body of sheet material bent alternately in opposite directions with formation of two mutually interleaved but substantially identical sets of projections on opposite sides of said body and with apertures at the peaks of said projections, said projections converging outwardly toward said apertures, the projections on one side forming depressions on the other side which are substantially the negative counterparts of said projections adjacent projections on opposite sides of said body being inter-connected by smoothly curved transition zones of generally S-shaped cross-section with middle portions extending within a common median plane of said body, said projections being at least one set of parallel ribs on each side.
2. A panel as defined in claim 1 wherein said apertures are slots extending longitudinally of said ribs.
3. A panel as defined in claim 1 wherein the ribs on each side are equispaced and symmetrically interleaved with the ribs on the respective opposite side.
4. A panel as defined in claim 1 wherein said transition zones are imperforate.
5. A panel for partly confining a fluid stream, comprising a body of sheet material bent alternately in opposite directions with formation of two mutually interleaved but substantially identical sets of projections in the form of pairs of longitudinally slotted rib segments on opposite sides of said body, said rib segments converging outwardly toward their longitudinal slots, the rib segments on one side forming depressions on the other side which are substantially the negative counterparts of said rib segments, adjacent rib segments on opposite sides of said body being interconnected by smoothly curved transition zones of generally S-shaped cross-section with middle portions extending within a common median plane of said body.
1. A panel for partly confining a fluid stream, comprising a body of sheet material bent alternately in opposite directions with formation of two mutually interleaved but substantially identical sets of projections on opposite sides of said body and with apertures at the peaks of said projections, said projections converging outwardly toward said apertures, the projections on one side forming depressions on the other side which are substantially the negative counterparts of said projections adjacent projections on opposite sides of said body being inter-connected by smoothly curved transition zones of generally S-shaped cross-section with middle portions extending within a common median plane of said body, said projections being at least one set of parallel ribs on each side.
2. A panel as defined in claim 1 wherein said apertures are slots extending longitudinally of said ribs.
3. A panel as defined in claim 1 wherein the ribs on each side are equispaced and symmetrically interleaved with the ribs on the respective opposite side.
4. A panel as defined in claim 1 wherein said transition zones are imperforate.
5. A panel for partly confining a fluid stream, comprising a body of sheet material bent alternately in opposite directions with formation of two mutually interleaved but substantially identical sets of projections in the form of pairs of longitudinally slotted rib segments on opposite sides of said body, said rib segments converging outwardly toward their longitudinal slots, the rib segments on one side forming depressions on the other side which are substantially the negative counterparts of said rib segments, adjacent rib segments on opposite sides of said body being interconnected by smoothly curved transition zones of generally S-shaped cross-section with middle portions extending within a common median plane of said body.
Description:
SPECIFICATION
Our present invention relates to a perforated panel of sound-absorbing character adapted to be used as part of a wall of a duct or plenum chamber serving for the circulation of heating or cooling air in, for example, an air-conditioning system of the "trickle" type in which the air stream is cooled by the evaporation of dispersed water.
In such a system the air may pass, under the pressure of a circulating pump, between a solid upper wall and a lower wall forming a false ceiling for a room to be cooled. The latter wall is advantageously composed of one or more perforated panels permitting some of the air under pressure to mix with the adjoining air volume. The peforations may also have a noise-absorbing function by breaking up acoustic wavefronts so as to dissipate some of the energy of the sound waves.
The general object of our invention is to provide a panel designed to facilitate a substantially uniform exchange of air or other fluids over a large area separating two spaces such as a plenum chamber or duct for a circulating air stream and a room to be cooled or heated thereby.
A more particular object is to provide a panel of this description which is of a highly sound-damping character so as to minimize the noise resulting from this fluid flow.
These objects are realized, in accordance with the present invention, by the provision of a body of sheet material which is bent alternately in opposite directions to form spaced-apart hollow projections or nozzles on each side separated by intervening depressions which are essentially (except for the distortion due to wall thickness) the negative counterparts of the projections, each projection being provided at its peak with one or more apertures which thus also lie at the bottom of a depression as seen from the opposite side of the panel.
With the projections converging outwardly toward their apertures, the air or other fluid moving along one side of the panel is gently deflected away from the proximal apertures, traversing them at a relatively reduced rate, but can pass more readily through the distal apertures after expanding into the depressions leading thereto. Given a certain inherent resiliency of the sheet material, the impingement of the fluid stream upon the curved, generally S-shaped boundaries of the alternating convexities and concavities is absorbed with little or no noise generation. These boundaries of generally S-shaped cross-section progressively approach each other across the entire width of the panel and constitute smoothly curved transition zones between the two sets of projections on opposite sides of the panel body.
The projections may be funnel-shaped or campaniform bosses or elongate ribs extending over all or part of the panel. In either case they may be uniformly distributed over one side in an array symmetrically interleaved with the projections of a similar array on the opposite side. Thus, for example, the bosses on one side could be disposed at the corners of identical squares whose centers are occupied by bosses projecting from the opposite side. Such squares may also be defined by intersecting ribs on either side.
The invention will be described in greater detail hereinafter with reference to the accompanying drawing in which:
FIG. 1 is a plan view of a panel embodying the invention;
FIG. 2 is a cross-sectional view taken on the line II -- II of FIG. 1;
FIG. 3 is a fragmentary perspective view of another panel according to the invention;
FIG. 4 is a view similar to FIG. 3, showing a modification;
FIG. 5 is a view similar to FIG. 1, illustrating a further embodiment; and
FIG. 6 is a cross-sectional view taken on the line VI -- VI of FIG. 5.
In FIGS. 1 and 2 we have shown a panel 1 of sheet material (e.g. foam plastic such as polystyrene) which is alternately bent in opposite directions to create upper and lower protuberances or projections 3, 5 in the form of funnel-shaped bosses provided with central apertures or ports 2 and 4, respectively. As will be apparent from FIG. 1, the lower apertures 4 lie at the centers of squares defined by the upper apertures 2, and vice versa. The two sides A and B of the panel are assumed to adjoin a high-pressure and a low-pressure region, respectively; these two sides are identically shaped except for a relative offset of the arrays of nozzles constituted by bosses 3 and 5. The upper and lower nozzles are aligned along the diagonals of the squares and, in the cross-sectional view of FIG. 2 taken along one such diagonal, are shown to be interconnected by smoothly curved transition zones in the form of generally S-shaped imperforate wall portions whose middle portions extend within a median plane.
The perforated projections or nozzles 3, 5 act as acoustic resonators having throats formed by the upper ports 2 and cavities constituted by adjoining air spaces. By virtue of their outwardly, i.e., downwardly converging shape, the lower bosses 5 intercept a major part of the wavefront of an acoustic wave which is therefore accelerated on its passage through the constricted necks 4 and attenuated by the frictional resistance of the fluid layers merging in that constriction. This results in a substantial increase in the noise-absorbing capacity of the panel material. Moreover, owing to the different flow rates through ports 2 and 4 as symbolized by the arrows in FIG. 2, the panel 1 behaves acoustically like a sheet with two sets of perforations of different diameters.
In FIG. 3 we have shown a modified panel 1' whose nozzles are formed by parallel ribs 3' and 5' projecting from the opposite sheet surfaces, the ribs being provided with respective rows of perforations 2' and 4'. Again, one set of projections, e.g., the upper ribs 3' may confront a plenum chamber whereas the other set, 5', faces a room to be heated or cooled. The aerodynamic and acoustic behavior of this panel is similar to that of the panel shown in FIGS. 1 and 2. Here, too, the body of the sheet is of generally S-shaped cross-section between alternating upper and lower projections.
FIG. 4 shows a generally similar panel 1" differing from panel 1' only by the fact that the apertures of its ribs 3" and 5" are in the form of longitudinally extending slots 2" and 4" in lieu of round holes 2' and 4'.
In FIGS. 5 and 6 we have shown a further panel 1'" whose projections 3'" and 5'" are in the shape of orthogonally intersecting rib segments provided with similarly intersecting slots 2'" and 4'", respectively. It will be noted that the pattern of the points of intersection of these slots is basically the same as that of the ports 2 and 4 of FIG. 1. Owing to the symmetry of its patterns, each of the panels 1, 1', etc. can be reversed without materially affecting the mode of operation.
Naturally, the shape of the apertures could differ from those illustrated, as by being elliptical, ovoid or polygonal. The widths of the apertures as well as their number depends, of course, upon the flow rate on the high-pressure side and the amount of fluid to be transferred to the low-pressure region. The regular distribution of these apertures, at the requisite density, insures a uniform spread of the cross-flow over the entire perforated area.
The constricted nozzle shape of the apertured projections lets the individual fluid jets issue at relatively low pressure with avoidance of turbulence which would tend to break up the fluid streams almost as soon as they leave the nozzles. Thus, the disclosed structure lets the jets penetrate well into the adjoining region to mingle with its atmosphere.
The panels described and illustrated may be molded directly to shape or could be deformed, under heat and pressure, from flat sheets of thermoplastic material.
Our present invention relates to a perforated panel of sound-absorbing character adapted to be used as part of a wall of a duct or plenum chamber serving for the circulation of heating or cooling air in, for example, an air-conditioning system of the "trickle" type in which the air stream is cooled by the evaporation of dispersed water.
In such a system the air may pass, under the pressure of a circulating pump, between a solid upper wall and a lower wall forming a false ceiling for a room to be cooled. The latter wall is advantageously composed of one or more perforated panels permitting some of the air under pressure to mix with the adjoining air volume. The peforations may also have a noise-absorbing function by breaking up acoustic wavefronts so as to dissipate some of the energy of the sound waves.
The general object of our invention is to provide a panel designed to facilitate a substantially uniform exchange of air or other fluids over a large area separating two spaces such as a plenum chamber or duct for a circulating air stream and a room to be cooled or heated thereby.
A more particular object is to provide a panel of this description which is of a highly sound-damping character so as to minimize the noise resulting from this fluid flow.
These objects are realized, in accordance with the present invention, by the provision of a body of sheet material which is bent alternately in opposite directions to form spaced-apart hollow projections or nozzles on each side separated by intervening depressions which are essentially (except for the distortion due to wall thickness) the negative counterparts of the projections, each projection being provided at its peak with one or more apertures which thus also lie at the bottom of a depression as seen from the opposite side of the panel.
With the projections converging outwardly toward their apertures, the air or other fluid moving along one side of the panel is gently deflected away from the proximal apertures, traversing them at a relatively reduced rate, but can pass more readily through the distal apertures after expanding into the depressions leading thereto. Given a certain inherent resiliency of the sheet material, the impingement of the fluid stream upon the curved, generally S-shaped boundaries of the alternating convexities and concavities is absorbed with little or no noise generation. These boundaries of generally S-shaped cross-section progressively approach each other across the entire width of the panel and constitute smoothly curved transition zones between the two sets of projections on opposite sides of the panel body.
The projections may be funnel-shaped or campaniform bosses or elongate ribs extending over all or part of the panel. In either case they may be uniformly distributed over one side in an array symmetrically interleaved with the projections of a similar array on the opposite side. Thus, for example, the bosses on one side could be disposed at the corners of identical squares whose centers are occupied by bosses projecting from the opposite side. Such squares may also be defined by intersecting ribs on either side.
The invention will be described in greater detail hereinafter with reference to the accompanying drawing in which:
FIG. 1 is a plan view of a panel embodying the invention;
FIG. 2 is a cross-sectional view taken on the line II -- II of FIG. 1;
FIG. 3 is a fragmentary perspective view of another panel according to the invention;
FIG. 4 is a view similar to FIG. 3, showing a modification;
FIG. 5 is a view similar to FIG. 1, illustrating a further embodiment; and
FIG. 6 is a cross-sectional view taken on the line VI -- VI of FIG. 5.
In FIGS. 1 and 2 we have shown a panel 1 of sheet material (e.g. foam plastic such as polystyrene) which is alternately bent in opposite directions to create upper and lower protuberances or projections 3, 5 in the form of funnel-shaped bosses provided with central apertures or ports 2 and 4, respectively. As will be apparent from FIG. 1, the lower apertures 4 lie at the centers of squares defined by the upper apertures 2, and vice versa. The two sides A and B of the panel are assumed to adjoin a high-pressure and a low-pressure region, respectively; these two sides are identically shaped except for a relative offset of the arrays of nozzles constituted by bosses 3 and 5. The upper and lower nozzles are aligned along the diagonals of the squares and, in the cross-sectional view of FIG. 2 taken along one such diagonal, are shown to be interconnected by smoothly curved transition zones in the form of generally S-shaped imperforate wall portions whose middle portions extend within a median plane.
The perforated projections or nozzles 3, 5 act as acoustic resonators having throats formed by the upper ports 2 and cavities constituted by adjoining air spaces. By virtue of their outwardly, i.e., downwardly converging shape, the lower bosses 5 intercept a major part of the wavefront of an acoustic wave which is therefore accelerated on its passage through the constricted necks 4 and attenuated by the frictional resistance of the fluid layers merging in that constriction. This results in a substantial increase in the noise-absorbing capacity of the panel material. Moreover, owing to the different flow rates through ports 2 and 4 as symbolized by the arrows in FIG. 2, the panel 1 behaves acoustically like a sheet with two sets of perforations of different diameters.
In FIG. 3 we have shown a modified panel 1' whose nozzles are formed by parallel ribs 3' and 5' projecting from the opposite sheet surfaces, the ribs being provided with respective rows of perforations 2' and 4'. Again, one set of projections, e.g., the upper ribs 3' may confront a plenum chamber whereas the other set, 5', faces a room to be heated or cooled. The aerodynamic and acoustic behavior of this panel is similar to that of the panel shown in FIGS. 1 and 2. Here, too, the body of the sheet is of generally S-shaped cross-section between alternating upper and lower projections.
FIG. 4 shows a generally similar panel 1" differing from panel 1' only by the fact that the apertures of its ribs 3" and 5" are in the form of longitudinally extending slots 2" and 4" in lieu of round holes 2' and 4'.
In FIGS. 5 and 6 we have shown a further panel 1'" whose projections 3'" and 5'" are in the shape of orthogonally intersecting rib segments provided with similarly intersecting slots 2'" and 4'", respectively. It will be noted that the pattern of the points of intersection of these slots is basically the same as that of the ports 2 and 4 of FIG. 1. Owing to the symmetry of its patterns, each of the panels 1, 1', etc. can be reversed without materially affecting the mode of operation.
Naturally, the shape of the apertures could differ from those illustrated, as by being elliptical, ovoid or polygonal. The widths of the apertures as well as their number depends, of course, upon the flow rate on the high-pressure side and the amount of fluid to be transferred to the low-pressure region. The regular distribution of these apertures, at the requisite density, insures a uniform spread of the cross-flow over the entire perforated area.
The constricted nozzle shape of the apertured projections lets the individual fluid jets issue at relatively low pressure with avoidance of turbulence which would tend to break up the fluid streams almost as soon as they leave the nozzles. Thus, the disclosed structure lets the jets penetrate well into the adjoining region to mingle with its atmosphere.
The panels described and illustrated may be molded directly to shape or could be deformed, under heat and pressure, from flat sheets of thermoplastic material.