Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
  • F24F13/02—Ducting arrangements
  • F24F13/0263—Insulation for air ducts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
  • F16L55/02—Energy absorbers; Noise absorbers
  • F16L55/027—Throttle passages
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
  • F16L55/02—Energy absorbers; Noise absorbers
  • F16L55/033—Noise absorbers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
  • F24F13/24—Means for preventing or suppressing noise

Definitions

• the present invention relates to a sound absorber that is intended to be mounted in a ventilation duct, said sound absorber comprising a casing and baffles provided in the casing, said baffles being symmetric in relation to a centre plane, that sound absorption material is included in the baffles, that the baffles are positioned in such a way relative to each other that secondary ducts are defined between adjacent baffles, said secondary ducts generally extending in the direction of the air flow.
• the invention also relates to a baffle per se.
• a sound absorber in the marketplace marketed under the trademark w RAE-Typgodkanda Ekodamparen ® " is equipped with an absorption material that is marketed under the trademark ⁇ kobel ® " .
• This absorption material has a uniform density and is included in aerodynamic baffles that are mounted inside a casing of the sound absorber in question.
• the baffles are protected by a surface layer that is alloted a type approval as regards cleansing accessibility, fibre relief and emission. If the air contains large amounts of solids the baffles may be covered by a perforated sheet metal .
• a sound absorber for air flow or gas flow is previously known.
• a flow duct is defined, said flow duct having a cross section that varies in the direction of the flow.
• the sound absorber contains on one hand insulation layers that generally damp noise and on the other hand compartments located outside the insulation layers, said compartments damping low sound frequencies.
• the insulation layers contain insulation of varying density.
• an air handling structure is previously known where the air flow in principle deflects 90° when passing through the air handling structure.
• baffles are contained, said baffles may include an external glass fibre mat and an acoustic filler material of low density, provided inside of the mat. It should be assumed that the baffles have an external material with a higher density than the interior material .
• a primary object of the present invention is to present a sound absorber that has an improved sound absorbing ability compared to known sound absorbers .
• Still an object of the present invention is to provide a proper sound absorption over the entire frequency area.
• a further object of the invention is to diffract the straight path of the sound.
• Figure 1 shows a schematic view of a sound absorber according to the present invention
• Figure 2 shows a top view, in enlarged scale, of an individual baffle
• Figure 3 shows a top view of an alternative embodiment of a baffle according to the present invention.
• the sound absorber shown in figure 1 comprises a casing 1 that is open at the opposite sides where the air flow that is to be sound dampened enters the sound absorber and leaves the sound absorber respectively.
• the air flow is symbolised by the arrow P in figure 1.
• baffles 3 Inside the casing 1 a number of identical baffles 3 are provided, said baffles 3 being assembled in such a way that secondary ducts 4 are defined between the baffles 3.
• the secondary ducts 4 have an angled extension in the view shown in figure 1, i.e. the extension of the secondary ducts 4 is not linear in the air flow direction.
• baffle 3 In order to describe a baffle 3 more in detail reference is made to figure 2. From the top view of a baffle 3, shown in figure 2, it is evident that one of its ends, the lower in • figure 2, has a first width Wl that is essentially larger than the second width 2 at the other end, the upper in figure 2, of the baffle 3. According to a preferred dimensioning of the baffle 3 the measure Wl may be good three times the measure W2.
• the baffle 3 has a wedge shape according to the view in figure 2. The distance between the ends of the baffle 3, i.e. its length, is marked with L in figure 2.
• the baffle 3 has also a certain height, i.e. its extension perpendicular to the paper in figure 2 , said height may vary within extensive limits and is normally adapted to the height of the ventilation duct, in which the sound absorber according to the present invention is mounted in.
• the baffle 3 shown in figure 2 is symmetric relative to a longitudinal centre plane C-C. Sound absorption materials are included as essential constituents in the baffle 3 shown in figure 2.
• the embodiment shown in figure 2 of a baffle 3 comprises two kinds of sound absorption material, a first sound absorption material being in the shape of two uniformly thick surface layers 5 that forms the sides surfaces of the baffle 3 and extend preferably along the entire height of the baffle 3.
• the first sound absorption material has preferably a density in the interval of 30-50 kg/m 3 .
• the surface layer 5 has preferably an external surface that is alloted a type approval as regards cleansing accessibility, fibre relief and emission.
• a second sound absorption material is provided, said material being in the shape of a core 7 that has a wedge shape in the view of figure 2.
• the second sound absorption material 7 has preferably a density in the interval 100-140 kg/m 3 .
• the sound absorption materials in the baffle 3 normally constitute an insulation material, e.g. rock wool, glass wool or cellulose fibres.
• a first perforated sheet 9 is provided centrally in the baffle 3, said sheet 9 coinciding with the centre plane C-C and extends generally between the ends of the baffle 3 and has an extension in height that generally corresponds to the height of the baffle 3. The first perforated sheet 9 is thus embedded in the core 7.
• a first mounting sheet 10 is provided at the lower end of the baffle 3 in figure 2, said first mounting sheet 10 preferably being perforated.
• the first mounting sheet 10 has folded edges and has a shape that generally adapts to the shape of the baffle 3.
• the first mounting sheet 10 has a height that extends between opposite sides of the casing 1, said sides being parallel to the paper in figure 1.
• the first mounting sheet 10 is in a suitable way attached to said parallel sides of the casing 1.
• a second mounting sheet 11 is provided at the upper end of the baffle in figure 2, said second mounting sheet 11 preferably being perforated.
• This second mounting sheet 11 has also folded edges and is adapted to the shape of the upper end of the baffle in figure 2.
• the second mounting sheet 11 has a height that extends between the opposite sides of the casing 1 that are parallel to the paper in figure 1, said second mounting sheet 11 being attached to said parallel sides of the casing 1 in a suitable way.
• the two mounting sheets 10 and 11 thus form a holder for the first and second sound insulation materials 5, 7 and the first perforated sheet 9. In this connection it should be pointed out that normally there is no connection between the first perforated sheet 9 and the mounting sheets 10 and 11.
• the sound absorber according to the present invention comprises thus a number of identical baffles 3 that according to a preferred embodiment are mutually arranged in the way that is shown in figure 1.
• the sound absorber shown in figure 1 has an extension in the direction of the air flow, i.e. in the direction of the arrow P, that corresponds to the measure 2L, where L is equal to the length of one baffle 3, see figure 2.
• the identical baffles 3 are so oriented in pairs that either the first mounting sheets 10 of two baffles 3 abut each other or the second mounting sheets 11 of two baffles 3 abut each other.
• the width B of the secondary ducts i.e. the distance measured perpendicular to side walls 5 of adjacent baffles 3, is normally in the interval of 50-125 mm. For widths in the lower area of the interval no possibility of look-through in the air flow direction of the sound absorber is present but for widths in the upper area of the interval a look-through in the air flow direction of the sound absorber is possible.
• the sound absorber shown in figure 1 functions in the following way. When air passes into the sound absorber the sound waves will penetrate the surface layer 5 that contains sound absorption material having proportionately low density. In connection therewith the surface layer 5 will absorb the high frequent sound waves . When the sound waves penetrates further into the baffles 3, i.e.
• this sound absorption material will absorb the sound waves having lower frequency.
• this sheet will absorb the sound waves having the lowest frequencies since the perforated sheet has an essentially higher density than the sound absorption material in the core 7.
• FIG 3 an alternative embodiment of a baffle 103 is shown.
• this baffle 103 comprises two surface layers 105 and an intermediate core 107 having an embedded perforated sheet 109.
• the densities of the sound absorption material that forms the surface layers 105 and the core 107 reference is made to what has been said above in connection with the description of the baffle 3.
• the shape of the baffle 103 it differs from the shape of the baffle 3 in the lower end in figures 2 and 3.
• the lower end of the baffle 103 is arc-shaped in the view shown in figure 3.
• the first mounting sheet 110 has a shape that adapts to the shape of the lower end of the baffle 103.
• the mounting sheets 110 and 111 are preferably perforated.
• baffles 103 When the baffles 103 are assembled in pairs to a sound absorber according to the present invention this is effected in principally the same way as is shown in figure 1. In case two first mounting sheets 110 will come into contact with each other this is effected only in the area of the most projecting portions of the first mounting sheets. What has been said above regarding the attachment of the mounting sheets 10 and 11 to the casing 1 is in principle also valid for the mounting sheets 110 and 111.
• a sound absorber that comprises baffles 103 functions in principle in the corresponding way as has been described above.
• the baffles 3; 103, according to the present invention, that has been described above are manufactured as separate units that are mounted in the casing 1 that is included in the sound absorber.
• the baffles 3; 103 have means, not shown in figures 2 and 3, that enable fastening of the baffles 3; 103 to the casing 1.
• These means may for instance constitutes sheets that are parallel to the paper in figures 2 and 3 and connected to the mounting sheets 10, 11; 110, 111.
• the mounting sheets 10, 11; 110, 111 may have folded flanges or the like at their ends. Since the baffles 3; 103 according to the present invention may be sold in the marketplace as separate units claims relating to an individual baffle 3; 103 have been set up below.
• the schematically shown preferred embodiment of a sound absorber according to the present invention has an extension in the direction of the air flow that corresponds to twice the length of the baffle 3.
• the sound absorber is expanded in the direction of the air flow with one or several sections that each has a length L.
• the sound absorber may also have an extension in the direction of the air flow that corresponds to the length of one baffle only.
• baffles 3 are identical, this of course being a major advantage from a manufacturing point. It is however in principle not necessary that the baffles that are included in a sound absorber according to the present invention are identical. Baffles in different sections may for instance have different lengths. In the embodiments described above of the baffles 3; 103 the mounting sheets 10, 11; 110, 111 are perforated. Within the scope of the present invention it is however feasible that the mounting sheets are not perforated.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Duct Arrangements (AREA)
• Soundproofing, Sound Blocking, And Sound Damping (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20287106

Family Applications (1)

Country Status (3)

Cited By (2)

Families Citing this family (1)

Citations (6)

• 2002
  • 2002-02-28 SE SE0200594A patent/SE525052C2/sv not_active IP Right Cessation
• 2003
  • 2003-02-25 AU AU2003212730A patent/AU2003212730A1/en not_active Abandoned
  • 2003-02-25 WO PCT/SE2003/000305 patent/WO2003073015A1/en not_active Application Discontinuation

Patent Citations (6)

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