Title:
Ventilating system
United States Patent 2172771


Abstract:
. This invention relates to improvements in ventilating systems for rooms and enclosures of all kinds, including offices, stores, restaurants, churches, auditoriums, schools, airplane cabins, railway cars, rooms of dwellings, etc. It is an object of the invention to provide improved means for...



Inventors:
Forbush, Norris Ralph
Application Number:
US6230136A
Publication Date:
09/12/1939
Filing Date:
02/04/1936
Assignee:
BURGESS BATTERY CO
Primary Class:
Other Classes:
52/506.08, 62/259.1, 62/296, 62/418, 165/48.1, 181/30, 181/224, 422/4, 454/186
International Classes:
F24D3/12; F24F7/10
View Patent Images:



Description:

. This invention relates to improvements in ventilating systems for rooms and enclosures of all kinds, including offices, stores, restaurants, churches, auditoriums, schools, airplane cabins, railway cars, rooms of dwellings, etc. It is an object of the invention to provide improved means for introducing air and distributing it in an enclosure without drafts, such as are created by air entering from ordinary registers and grilles. The object is attained by causing the air to enter the enclosure at low velocity at distributed points over a large area.

It is a further object of the Invention to Incorporate an acoustical treatment with the improved ventilating system.

It is a further object of the invention to provide heating or cooling means, or both, in combination with the improved ventilating system.

Other objects and advantages of the invention will become apparent from a reading of the following specification. In the drawings: Fig. 1 is a longitudinal, sectional view of an enclosure which is equipped with my improved combined ventilating system and acoustical treatment; FPg. 2 is a fragmental perspective view of a portion of the construction of Fig. 1; Figs. 3, 4 and 5 are fragmental perspective views of modifications of the construction of this invention; Fig. 6 is a fragmental, sectional view of a further modification of the invention; Figs. 7 and 8 are fragmental, sectional views of modifications of the invention in which heating or cooling means, or both, are incorporated with the ventilating means; and, Figs. 9, 10 and 11 are perspective views of different modifications of combined air-distributing and sound-absorbing units which may be used in my invention.

In Figs. 1 and 2 there is illustrated a building 10 containing a ventilating system in accordance .with the invention. A one-room store building is shown for purposes of illustration, having a front wall II, a rear wall 12, a main floor 13 and a basement 14. A partition 15 separates the main room 16, which is'to be ventilated, from a space 17 at the rear of the building.

A number of beams 18 are suspended from the ceiling 19 of the room 16 by means of relatively long bolts 20. Furring strips 21 are attached to beams 18 by suitable attaching means, such as nails or screws (not shown) and a sheetform foraminous member 22 is supported by the furring strips. Foraminous member 22 is of an area substantially equal to the area of the floor of room 16 and may be made up of a plurality of pan-like perforated tiles 23 of self-sustaining material. The tiles may be metal sheets, vulcanized fiber sheets, bakelized sheets, wood veneer sheets, or the like. Within each tile 23, and substantially filling the same, is a panel 24 of sound-absorbing material. The assembly of these panels forms a partition between the foraminous member and the ceiling. The panels may be composed of matted wood fibers, hairfelt, mineral wool, or of other suitable porous, air-pervious material. The arrangement of furring strips, foraminous tiles and sound-absorbing panels may be like that shown in my United States Patents Nos. 1,726,500 and 1,833,174 granted August 27, 1929 and November 24, 1931, respectively. The foraminous tile of the Sullivan Patent No. 1,918,149, granted July 11, 1933 and the furring strips of the Weiss Patent No. 1,738,469, granted December 3, 1929, may also be used. The panels 24 may be spaced from the tiles 23 by means of spacing members 25. Such spacing avoids the uneven light reflection which may otherwise take place through the perforations of the tiles due to the surface irregularities of the panel.

The ventilating system comprises an air inlet conduit 27 which leads to an air conditioning unit 28. This unit may include apparatus for washing, filtering, humidifying, cooling, etc. A condensing unit for a refrigerator is indicated at 29. The air may be drawn through this apparatus by a fan 30 and forced into conduit 31, which may have a heater unit 32 associated therewith. The end portion of conduit 31 may have a lining of sound-absorbing material 33, faced with foraminous metal 34 or other foraminous smooth-surfaced material (see Fig. 2).

The entire conduit may be lined, but it has been found in most cases to be sufficient to line a portion adjacent the fan outlet and a portion adjacent the conduit outlet. In view of the presence of sound-absorbing material 24, a soundabsorbing lining at the end portion of the conduit is sufficient. The end portion of the conduit may be flattened as shown. Registers or grilles 35 are located at distributed points in the lower portions of the walls of the room, and are connected to return conduits 36 and 37, which may be used to conduct the air back to the air conditioning unit 28 and the fan 30, if it is desired to re-circulate the air.

The space 38 between the collection of panels 24 and the ceiling 19 forms a plenum chamber into which the air is introduced continuously by the air-circulating means. The air spreads freely and uniformly throughout chamber 38 and is maintained there at a pressure slightly above the pressure level in room 16 as will be erplained more fully hereinafter. The air passes through the sound-absorbing panels 24 and then through member 22, the distribution of air flow being substantially uniform throughout the area of the latter. Foraminous member 22 is of sufficient area and the perforations therein are sufficiently numerous that the air passes through it at low velocity and descends into the room throughout its entire area in a gentle movement which is not perceptible to the occupants.

There are no drafts, such as are present when an ordinary ventilating system, in which the air is introduced into the room by means of grilles or registers, is used.

In the construction illustrated in Fig. 3 a plurality of elongated hollow beams 42 are supported by pillars 43 beneath the ceiling 44 and are arranged in spaced, parallel relation. The hollow members 42 are connected at one end to the air inlet conduit 41. The air inlet conduit 41 may be arranged along the side wall 45 of the room as shown. It may also supply ventilating air to a similarly arranged construction in a room on the opposite side of wall 45. Foraminous sheet-form tiles 46, carrying sound-absorbing panels 47, may be supported in any suitable manner between the hollow beams 42, and in spaced relation to the ceiling 44. Plenum chambers 48 are thus formed between the tiles and the ceiling. The tiles may be relatively large, as shown, and may have grooves 49 formed therein. These grooves give the appearance of smaller tiles for decorative purposes. The sound-absorbing panels may be large also, to conform with the size of the tiles. This results in manufacturing and installation convenience and economy. The hollow beams 42 have slots 50 in both side walls, the slots communicating with the plenum chambers 48. The entering air passes through air inlet conduit 41 into hollow beams 42 and passes through slots 50, into the plenum chambers 48. It then passes through the apertures in foraminous tiles 46 and downwardly into the room.

Fig. 4 illustrates a construction in which the foraminous member is supported directly by the supporting structure for the floor above, and forms the permanent ceiling of the room to be ventilated. It is adapted especially for application to new buildings in which the ventilating system is incorporated in the design of the building. The joists 55 support the floor 56 of the room above. The inlet conduit 57 for the ventilating air is arranged between two of the joists 55.

Blocks 58 are attached to the bottom edges of joists 55 at spaced intervals and furring strips 59 are attached to blocks 58. Foraminous tiles 60, carrying sound-absorbing panels 61 are supported by furring strips 59 in the manner described heretofore. Blocks 58 serve to space panels 61 and the turned-up edges of the tiles 60 from the bottom edges of joists 55 so as to permit the free movement of the ventilating air into all of the space between the floor 56 and the panels 61.

The construction of Fig. 5 is similar to that of Fig. 4, except that the sound-absorbing panels are attached to the under side of the floor of the room above, instead of being carried by the foraminous tiles. They are shown wrapped in sound-transparent coverings 62, an expedient that may be used to prevent sifting of the sound-absorbing material into the room below. The same numbers are used in Fig. 5 to designate parts corresponding to similar parts in Fig. 4.

Fig. 6 shows a construction similar to that shown in Fig. 4 except that the blocks 58 of Fig. 4 are omitted, and the sound-absorbing panels and the tiles are spaced from the bottom edges of the joists 55 by providing long legs upon the furring strips 59, as shown. This figure shows the engagement between tongues 64 on the turned-up edges of the tiles and the slots 83 in the furring strips. The same numbers are used in Pig. 6 to designate parts corresponding to the parts of Fig. 4.

.Fg. 7 shows a construction in which means are I provided for heating and cooling the ventilating air in the plenum chamber. This construction also shows a modification of the means for introducing the ventilating air into the plenum chamber. The ceiling 85 is shown as being corposed of concrete, with facing layer 6( of plaster, although it may be of any suitable composition.

Pipes t7 for containing the circulating heating or cooling means are embedded in the ceiling. The foraminous tiles 10 are supported in position by u supporting means of the type described and claimed in the Sullivan Patent No. 1,776,092, comprising bolts 71 embedded in the ceiling, clips 12, and furring strips 73. Tiles 10 carry soundabsorbing panels 79 in the manner described here- go tofore. In order to conceal the furring strips adjacent the side walls 74 a border of narrow tiles 75 is arranged as shown.

The construction is omitted from one or more small areas of the ceiling and a fan 76 is in- U5 stalled at each such area by mounting the fan in a suitable manner upon the ceiling. The fan is arranged to draw air upwardly out of the room and discharge it into the plenum chamber 77, between the ceiling and the foraminous member S0 formed by the tiles 70. In such construction the circulating heating or cooling medium usually is water. Heat is conducted from the pipes 67 to the surface layer 66 of the ceiling and radiated from this surface into the plenum chamber. It U3 is then carried downwardly by the air into the room in a gentle movement over substantially the entire area of the room. As indicated heretofore, the construction may be so arranged that during the warm weather pipes 67 carry a cooling medium, such as cold water, in which case the ventilating system may be used to cool the room.

A border of narrow finishing tiles 15 may be used around the areas occupied by the fans 76 as shown. 46 Fig. 8 shows a construction in which the tiles making up the foraminous member are supported in a manner similar to that described in Burgess application, Serial No. 503,542, filed December 19, 1930. A sheet-or plate-form supporting member 80 is attached to the ceiling 81 by suitable means, such as screws 82. Supporting member 80 has beams 83 depending therefrom, which beams may be in the form of integral ribs of the plate 80. Beams 83 have openings therein, indicated at 84, to permit the free flow of air into the entire plenum chamber. Beams 83 have flanges 85 at the ends thereof. Porous sound-absorbing panels 86 rest at their edges upon flanges 85 and extend adjacent ribs. Panels 86 are of rigid construction and may be composed of cemented wood fibres, or may be the ceramic tiles of Kliefoth Patents Nos. 1,966,069 and 1,976,946. In this construction the sheet-form foraminous member may be omitted. A relatively large opening may be provided in one of the panels and fan 87 may be arranged in such opening. Heating and cooling pipes 88 may be located in the plenum chamber and supported by means of straps 89 and rods 90, the latter being embedded in the ceiling. The action is substantially the same as that described in connection with Fig. 7. The flow of air from the plenum chamber 91 into the room is regulated by the porous, air-pervious sound-absorbing tiles 86, Heat is radiated from 15 pipes 88 and carried into the room by the moving air.

It has been stated heretofore that the sound absorbing panels are of porous air-pervious composition. These panels are relatively thick, usually about one inch thick and if the air is caused to pass through them, as it does in the construction of Pigs. 1, 2 and 8, they provide a means for regulating the flow of air from the plenum chamber into the room because of the resistance they offer to the flow. The foraminous member frequently is of sufficiently open character that unless additional means are provided for thus regulating the flow, a large proportion of the air follows the path it would naturally take if there were no plenum chamber. For even distribution over the entire area of the foraminous member, the resistance to flow therethrough should be such that a slight, but appreciable pressure is built up in the plenum chamber. By making the thick sound-absorbing panels of the proper density and arranging them so that they are substantially co-extensive with the tiles, they afford the required resistance and substantially uniform flow is obtained over the entire area of the foraminous member. Uncovered panels one inch thick, composed of matted wood fibres and weighing about 0.40 pound per square foot, marketed under the trade-mark "Balsam-Wool" are satisfactory for the purpose.

In accordance with this invention, a slight pressure may be maintained in the plenum chamber and uniform distribution of air flow obtained without causing the air to pass through the sound-absorbing panels. This is accomplished by enclosing the individual panels in sound-transparent wrappers which are substantially impervious to the passage of air under the conditions of use and spacing the panels a slight distance apart so that resistance is offered to the flow of air between adjacent panels and the desired slight pressure is built up in the plenum chamber. The assembly of panels forms the controlling partition through which air may pass at predetermined points and at a predetermined rate of flow. Such a wrapper may be a th'n paper or metal foil wrapper, as shown in Fig. 10.

Such a wrapper does not impair the acoustic effectiveness of the sound absorbing panel. The wrapped panels may be placed in contiguous relation to the foraminoud member, that is, in contact therewith or in spaced adjacent relation thereto. Where the foraminous member is made up of a plurality of pan-shaped tiles the wrapped 65 panels should be slightly smaller in length and width than the tiles. To give a practical example, in a construction where the individual tiles are two square feet in area, the foraminous member is 350 square feet in total area and the flow of ventilating airi into the room varies from 500 to 3500 cubic feet per minute, panels which are one-half Inch smaller than the tiles in both length and width, providing one-fourth inch spacing between the correspond'ng edges of each panel and tile, have been found to be satisfactory.

An appreciable pressure is maintained in the plenum chamber and a steady, uniformly distributed flow is obtained under such conditions.

With a half inch spacing between the corresponding edges of the panels and the tiles in this construction the pressure in the plenum chamber is negligible and the flow is not uniformly distributed. The spacing requirements vary for different conditions of air flow rate, tile size and area 76 of the foraminous member.

Uniform distribution of air flow may also be obtained by arranging the wrapped panels upon the foraminous member so as to be increasingly close together as they approach the areas where the air would otherwise flow through the foraminous member in the greatest quantities. This may not be the area immediately adjacent the point where the air enters the plenum chamber.

Where the outlet of the air supply conduit is substantially parallel with the surface of the foraminous member, as shown in Figs. 1 and 2, the air naturally turns downwardly into the room at a considerable distance from the end of the conduit. Such graduated spacing is particularly useful where the air flow is small and little or no air pressure is maintained in the plenum chamber.

The spacing may be obtained by providing the wrapped sound-absorbing panels in varying sizes, the larger ones almost completely filling the foraminous tiles, and the smaller ones leaving spaces between the edges of panels and the turnedup edges of the tiles. Such arrangements are 11lustrated in Figs. 9 and 10. In Fig. 9 the foraminous tile 92 contains porous sound-absorbing panel 93 which is enclosed in paper or metal foil wrapper 94. The wrapper may be folded at the ends of the panel, as shown at 95. The panel is spaced from the tile face by means of spacing members 96. The panel 93 almost fills tile 92, that is, its length and width are only slightly less than the length and width of the tile. Space should be provided along two sides for the accommodation of the legs of the furring strips, which are located inside the turned-up edges of the tiles, see Figs. 6 and 7. In such an arrangement the passage of the ventilating air through the foraminous tile 92 is greatly restricted. Having passed through the openings between adjacent panels the air spreads over the face of tile 92 and passes downwardly into the room. The same result may be obtained with an unwrapped panel if the top or the bottom surface of the panel is covered with a layer of paper or metal foil. Fig. 9 also shows the tile 92 as being of greater length than width and having a groove 97 extending across the middle thereof whereby it has the appearance of being two tiles of square shape.

In Fig. 10 an arrangement is shown in which the sound-absorbing panel is substantially smaller than the tile. The same numbers are used in Fig. 10 to designate parts corresponding to the numbered parts of Fig. 9. This arrangement allows substantially unrestricted flow between the panel and the turned-up edges of the tile.

It may be permissible in some installations to omit the spacers 96 between the tiles and the sound-absorbing panels as shown in Fig. 11, in which case the desired distribution of air flow is obtained by the blocking off of the portions of the tiles which are covered by the panels rather than by restricting the flow between the edges of the panels and the turned up edges of the tiles.

In such arrangements smaller panels are used since a greater area of the foraminous member is required to provide a flow equal to that provided 66 by the free spaces between the edges of adjacent panels. The same numbers are used in Fig. 11 to designate parts corresponding to the parts of Figs. 9 and 10.

A further arrangement for providing uniform flcw over the area of the foraminous member is illustrated in Fig. 4. In this arrangement, alternate ones of the sound-absorbing panels 61 are enclosed in sound-transparent and substantially air-impervious wrappers 62. The panels substantially fill the corresponding foraminous tiles 60 with the result that the passage of air is prevented through these tiles containing the wrapped panels. Such construction is particularly useful where the panels are composed of a material of such open porosity that insufficient pressure is maintained in the plenum chamber if all of the panels are unwrapped.

I claim: 1. In a ventilating system, the combination with a wall or ceiling of a space to be ventilated, of an extended sheet-form foraminous member spaced interiorly from said wall or ceiling, a partitian of substantially air-impervious material having distributed openings therethrough between said foraminous member and said wall or ceiling and in spaced relation to said wall or ceiling to form a plenum chamber between said partition and said wall or ceiling, and means for introducing ventilating air into said plenum chamber, the total area of said openings in said partition bearing such relation to the total area of said partition that said air introduced into said plenum chamber builds up a low but appreciable pressure therein, whereby to cause said air to pass.through substantially all of the openings of said partition at substantially the same velocity.

2. In a ventilating system, the combination with a wall or ceiling of a space to be ventilated, 80 of an extended sheet-form foraminous member spaced interiorly from said wall or ceiling to form an enclosure therebetween, a partition of subslantially air-impervious material within said enclosure substantially parallel to said foraminous member and spaced from said wall or ceiling to form a chamber between said partition and said wall or ceiling, a plurality of openings in said partition, and means for introducing air into said chamber, said partition being of such area and said openings therein being so arranged that air enters the room at low velocity.

3. In a ventilating system, the combination with a wall or ceiling of a space to be ventilated, of an extended sheet-form foraminous member spaced interiorly from said wall or ceiling, a plurality of substantially air-impervious panels positioned in a plane between said foraminous member and said wall or ceiling and in spaced relation to said wall or ceiling to form a plenum chamber between said air-impervious panels and said wall or ceiling, and means for introducing ventilating air into said plenum chamber, said air-impervious panels being spaced apart in such relation to each other that the total area of opening between said panels bears such proportion to the total area of said air-impervious panels that said air introduced into said plenum chamber builds up a low but appreciable pressure therein whereby to cause said air to pass between said air-impervious panels at a velocity substantially uniform throughout the area of the totality of said air-impervious panels.

4. In a ventilating system, the combination with the ceiling of a space to be ventilated, of an extended sheet-form foraminous member spaced interiorly from said ceiling, a partition of substantially air-impervious material having distributed openings therethrough between said foraminous member and said ceiling and in spaced relation to said ceiling to form a plenum chamber between said partition and said ceiling, means for introducing ventilating air into said plenum chamber, and means for exhausting said air from said space at one or more points near the floor thereof, the total area of said openings in said partition bearing such relation to the total area of said partition that said air introduced into said plenum chamber builds up a low but appreciable pressure therein whereby to cause said air to pass through substantially all of the openings of said partition at substantially the same velocity.

5. In a ventilating system, the combination with a wall or ceiling of the room to be ventilated, of a sheet-form foraminous member spaced interiorly from said wall or ceiling to form a chamber, a substantially air-impervious member upon said foraminous member, said air-impervious member incompletely covering said foraminous member to form distributed small uncovered areas, and means for introducing ventilating air into said chamber, the uncovered area of said -fcraminous member being such that a slight pressure is maintained in said chamber.

6. In a ventilating system, the combination with a wall or ceiling of the room to be ventilated, of a sheet-like foraminous member spaced interiorly from said wall or ceiling to form a chamber, a plurality of sound-absorbing units in said chamber and contiguous to said foraminous member, sound-transparent but substantially airimpervious covers for said units, and means for introducing ventilating air into. the space between said units and said wall or ceiling, said units being arranged in such proximity to one another that substantially even distribution of air flow is obtained throughout the area of said foraminous member.

7. In a ventilating system, the combination with a wall or ceiling of the room to be ventilated, of a sheet-form foraminous member spaced interiorly from said wall or ceiling to form a chamber, a plurality of sound-absorbing units upon said foraminous member and in contact therewith, sound-transparent and substantially air-impervious coverings for said sound-absorbing units, and means for introducing ventilating air into said chamber, said absorbing units incompletely covering said foraminous member, the uncovered area of said foraminous member being such that a slight pressure is maintained in said chamber.

8. The construction of claim 7 in which the sound-absorbing units are in the form of panels of porous sound-absorbing material and the coverings are in the form of wrappers of substantially air-impervious sheet material.

9. In a ventilating system, the combination with a wall or ceiling of a room to be ventilated, of a sheet-form foraminous member spaced interiorly from said wall or ceiling to form a chamber, a sound-absorbing but substantially air-impervious member upon said foraminous member, said air-impervious member incompletely covering said foraminous member to form distributed small uncovered areas, and means for introducing ventilating air into said chamber, the uncovered area of said foraminous member being such that a slight pressure is maintained in said plenum chamber. 10. In a ventilating system, the combination with a wall or ceiling of a space to be ventilated of an extended sheet-form foraminous member spaced interiorly from said wall or ceiling to form an enclosure therebetween, a partition of soundabsorbing substantially air-impervious material within said enclosure substatially parallel to said foraminous member and spaced from said wall or ceiling to form a chamber between said partition and said wall or ceiling, a plurality of distributed passageways through said partition, and means for introducing air into said chamber, said partition being of such area and said passageways being so dimensioned and arranged that air enters the room at low velocity.

11. In a ventilating system, the combination with a wall or ceiling of a space to be ventilated of an extended sheet-form foraminous member spaced interiorly from said wall or ceiling to form an enclosure therebetween, a partition of soundabsorbing material having a substantially airimpervious covering within said enclosure substantially parallel to said foraminous member and spaced from said wall or ceiling to form a chamber between said partition and said wall or ceiling, a plurality of distributed passageways through said partition, and means for introducing ventilating air into said chamber, said partition being of such area and said passageways therein being so dimensioned and arranged that air enters the room at low velocity.

12. In a ventilating system, the combination of a floor, longitudinal joists supporting said floor, a sheet-like foraminous member mounted in spaced relation to said floor and to the bottom edges of said joists to form a chamber, a plurality of sound-absorbing units in said chamber and contiguous to said foraminous member, soundtransparent but substantially air-impervious covers for said units, and means for introducing ventilating air into the space between said units and said floor, said units being arranged in such proximity to one another that substantially even distribution of air flow is obtained throughout the area of said foraminous member.

13. In a ventilating system, the combination of the ceiling of the room to be ventilated, a ventilating duct extending adjacent the surface of said ceiling, means for supplying ventilating air to said duct, a plurality of hollow beams extending from said ventilating duct and supporting said ceiling and arranged in spaced relation to each other, said ventilating duct having openings to communicate with the interior of said hollow beams, and sheet-form foraminous members extending between said hollow beams and in spaced substantially parallel relation to said ceiling and substantially covering the exposed area of said ceiling, said hollow beams having openings therein connecting with the spaces between said foraminous members and said ceiling, the total area of said foraminous members being such that the ventilating air passes through said members into the room to be ventilated at low velocity. 14. In a ventilating system, the combination of the ceiling of a room to be ventilated, a ventilating duct extending adjacent the surface of said ceiling, means for supplying ventilating air to said duct, a plurality of branch ducts connected go to said first duct and extending subjacent said ceiling in spaced relation to each other, and sheetform foraminous members extending between said branch ducts and in spaced substantially parallel relation to said ceiling and substantially covering the exposed area of said ceiling, said branch ducts having openings therein connecting the interiors thereof with the spaces between said foraminous members and said ceiling adjacent thereto, the total open area of said foraminous members through which air may pass being such that said air passes through said members into the room to be ventilated at substantially uniform velocity throughout the area thereof.

15. In a ventilating system, in combination, a room to be ventilated and a ceiling thereof, a plurality of substantially parallel ventilating ducts adjacent said ceiling, means for continuously supplying ventilating air to said ducts, an apertured sheet-like member of sound-absorbing material spaced from said ceiling, and distributed openings in the walls of said ducts betwen said ceiling and said apertured member, said apertured member being so constructed that air passing from said ducts through said openings in the walls 10 thereof is caused to pass through substantially all apertures in said member at a substantially uniform velocity.

16. In a ventilating system, the combination of a wall or ceiling of the room to be ventilated, a sheet-like foraminous member of sound-absorbing material spaced from said wall or ceiling to form a chamber, said foraminous member having an area comparable to the wall or ceiling area of said room, said foraminous member having a relatively large opening therein, said opening being in direct communication with said room and said chamber, and air-impelling means located in said opening and adapted to impel air from said room through said opening into said chamber.

17. In a ventilating system, the combination of a wall or ceiling of the room to be ventilated, a sheet-like foraminous member of sound-absorb-30 ing material spaced from said wall or ceiling to form a chamber, said foraminous member having an area comparable to the wall or ceiling area of said room, said foraminous member having a relatively large opening therein, said opening being in direct communication with said room and said chamber, air-impelling means located in said opening and adapted to impel air from said room through said opening into said chamber, and means for heating the air in said chamber.

18. In a ventilating system, the combination of a wall or ceiling of the room to be ventilated, a sheet-like foraminous member of sound-absorbing material spaced from said wall or ceiling to form a chamber, said foraminous member having an area comparable to the wall or ceiling area of said room, said foraminous member having a relatively large opening therein, said opening being in direct communication with said room and said chamber, air-impelling means located in said opening and adapted to impel air from said 50 room through said opening into said chamber, and air heating and cooling pipes located in said chamber.

19. In a ventilating system, the combination with a wall or ceiling of the room to be ventilated of a sheet-like foraminous member spaced interiorly from said wall or ceiling to form a chamber, a plurality of sound-absorbing units in said chamber and contiguous to said foraminous member, sound-transparent but substantial- W ly air-impervious covers for said units, means for introducing ventilating air into the space between said units and said wall or ceiling, and means for varying the temperature of the air in said chamber, said units being arranged in such proximity to one another that a predetermined distribution of air flow is obtained throughout the area of said foraminous member.

RALPH FORBUSH NORRIS.