US3577904A

US3577904A - Suspended ceiling integrated air distribution system

Info

Publication number: US3577904A
Application number: US815835A
Authority: US
Inventors: Robert R Lambert
Original assignee: Individual
Current assignee: Venturedyne Ltd
Priority date: 1969-04-14
Filing date: 1969-04-14
Publication date: 1971-05-11
Anticipated expiration: 1988-05-11

Abstract

A plurality of air distribution subassemblies, each having spaced sidewalls defining an air distribution passage therebetween, are mounted in a linear array transversely of a plurality of preexisting suspended ceiling main runner members, in one embodiment straddling cross T-bar members spanning the distance between said main runners, wherein a continuous air supply plenum is mounted on two or more adjacent subassemblies of such air distribution subassemblies with a continuous air supply outlet therein along a lower portion thereof and extending across the associated main runner, and in one said embodiment across the intersection of a main runner and across T-bar, to provide an effectively continuous linear air distribution passage through said ceiling across the main support members of the preexisting ceiling grid or support system.

Description

United States Patent [72] Inventor Robert R. Lambert 442 W. Leadora Ave., Glendnra, Calif. 91740 [21] Appl. No. 815,835 [22] Filed Apr. 14, 1969 [45] Patented May 11, 1971 [54] SUSPENDED CEILING INTEGRATED AIR DISTRIBUTION SYSTEM 6 Claims, 9 Drawing Figs.

[52] US. Cl 98/40, 52/303 [51] Int. Cl F24f 13/06 [50] Field of Search 98/400, 40, 400 (L); 52/665, 303, 201, 204

[5 6] References Cited UNITED STATES PATENTS 3,187,661 6/1965 Dail .6 98/40 ABSTRACT: A plurality of air distribution subassemblies,

each having spaced sidewalls defining an air distribution passage therebetween, are mounted in a linear array transversely of a plurality of preexisting suspended ceiling main runner members, in one embodiment straddling cross T-bar members spanning the distance between said main runners, wherein a continuous air supply plenum is mounted on two or more adjacent subassemblies of such air distribution subassemblies with a continuous air supply outlet therein along a lower portion thereof and extending across the associated main runner, and in one said embodiment across the intersection of a main runner and across T-bar, to provide an effectively continuous linear air distribution passage through said ceiling across the main support members of the preexisting ceiling grid or support system.

Pate nted May 11, 1971 4 Sheets-Sheet 1' J INVENTO/Q RoaserB. 10/115587 3 ma, a ,Mz

' p7- roeA/Ew'.

Patented May 11, 1971 4 Sheets-Sheet 4 l'zvvewro e. 206527 R 2 145.52 r .7 $7M, a; a fad firr e/vsus.

SUSPENDED CEILING INTEGRATED AIR DISTRIBUTION SYSTEM BACKGROUND OF THE INVENTION Many suspended ceiling installations have been made in the past wherein a grid of main and cross inverted T-bars are used for supporting acoustical tile suspended from a ceiling or soffit thereabove. Various air distribution systems have been devised heretofore which can be incorporated in such suspended ceiling systems as a part of the original design thereof and in some instances, as an added, later installed system. The invention of the present application is directed to ceiling integrated air distribution systems of the later type wherein an air distribution system is to be installed in a preexisting suspended ceiling grid.

Heretofore, continuous linear air distribution through a ceiling has been effected only by means of an originally incorporated continuous air 'bar member which is installed originally as part of the ceiling structure for suspending the ceiling tile. In adding air distribution systems to preexisting ceiling grids where main and cross T-bars have already been installed, the air distribution systems have taken the form of plug-in individual units which may be located in various portions of the ceiling. None of these latter added air distribution systems have provided an effectively continuous linear air distribution system along a ceiling which operates and functions in the manner of the aforementioned originally installed linear air distribution means.

By way of example, in my prior US. Pat. No. 3,406,623 l disclose a plenum air diffuser assembly adapted to be seated upon the preexisting inverted T-bar support members for the ceiling, and in an alternative embodiment therein, to straddle certain of the preexisting inverted T-bars. These units were individually supplied with conditioned air through the use of flex ducts to their individual plenums. An effectively continuous air supply across the suspended ceiling main runners, and particularly the intersection of the main runners and the cross T- bars, was not accomplished.

OBJECTIVES AND INVENTION SUMMARY It is therefore the primary objective of the present invention to disclose and provide a suspended ceiling integrated air distribution assembly which can be easily assembled into a preexisting suspended ceiling grid of inverted T-bars and thereby provide an effectively continuous linear air distribution means along the ceiling even though the ceiling has been originally installed as a noncontinuous, interrupted grid of crossed ceiling support members.

It is a further object of the present invention to disclose a ceiling integrated air distribution assembly as in the foregoing object wherein a plurality of air distribution subassemblies may be installed between the suspended ceiling main runners with a single continuous air supply duct mounted thereto for supplyingair to adjacent subassemblies across a ceiling main runner positioned between said adjacent subassemblies.

It is a still further object of the present invention to disclose and provide a suspended ceiling integrated air distribution assembly as in the foregoing objects wherein the plurality of subassemblies may be positioned on the spaced ceiling main runners and straddling the ceiling cross T-bar members to provide an effectively continuous linear air distribution means along the crossbars and across the intersection-between said crossbars and main runners.

It is another object of the present invention to disclose and provide a ceiling integrated air distribution assembly as in the foregoing objects wherein certain individual subassemblies of the linear array thereof may be utilized for return air into the ceiling plenum of the suspended ceiling while other adjacent subassemblies are utilized for air supply across the intersection with main runners and main and cross runners as hereinbeforc stated.

Generally stated, the foregoing objects are obtained'by the ceiling integrated air distribution assembly in accordance with the present invention through the provision of a plurality of air distribution subassemblies, each having spaced sidewalls defining an air distribution passage therebetween and the subassemblies being mounted in a continuous linear array transversely of and extending between the main T-bar members of a preexisting ceiling system. In the preferred exemplary embodiment of the present invention, such subassemblies are mounted on the main T-bars straddling cross T-bar members, which then become part of the air distribution subassembly, while in the alternative exemplary embodiment such subassemblies are independently supported between said main runners.

Further, a continuous air supply plenum, supplied by a single source of conditioned air, is mounted on and supported by a plurality of adjacent linearly disposed air distribution subassemblies with the plenum having a continuous air supply outlet along alower portion thereof which extends across at least one intersection of a main T-bar and adjacent subassemblies. In the preferred embodiment, such intersection is also the intersection between the main T-bar and the cross T-bars which the subassemblies straddle.

A more complete understanding of the suspended ceiling integrated air distribution assembly, in accordance with the present invention, will be attained by those skilled in the art, and various other objects and advantages of the present invention will be made known, from a consideration of the following detailed explanation of two exemplary embodiments thereof. Reference will be made to the appended sheets of drawings in which:

IN THE DRAWINGS FIG. 1 is a perspective view of an exemplary suspended ceiling support structure or grid of inverted I-bar members with which a preferred exemplary embodiment of the suspended ceiling integrated air distribution system according to the present invention is illustrated in exploded relationship;

FIG. 2 is a cross section view of the airdistribution system of FIG. 1. integrated into the suspended ceiling of FIG. 1;

FIG. 3 is a longitudinal, detail sectional view taken in the plane Ill-III of FIG. 2;

FIG. 4 is an exploded perspective view of an end of one of the diffuser assembly components of the assembly of FIGS. I through 3 shown prior to its integration into the ceiling support structure;

FIG. 5 is a detail view, in perspective, of a portion of the air distribution system of FIGS. I through 4 at an intersection of the inverted T-bars of the ceiling grid or support system;

FIG. 6 is a perspective view of an alternative exemplary embodiment of the suspended ceiling integrated air distribution system according to the present invention;

FIG. 7 is a cross-sectional view of the air distribution system of FIG. 6 taken therein along the plane VII-VII;

FIG. 8 is another cross-sectional view of the system of FIG. 6 taken therein along the plane VIII-VIII; and

FIG. 9 is an exploded detail view, in perspective, of a portion of the diffuser assembly of the alternative exemplary embodiment of FIGS. 6 through 8.

Referring first to the preferred exemplary embodiment of FIGS. 1 through 5, it can be seen that the air distribution system in accordance with the present invention may be integrated into a preexisting suspended ceiling system or grid of crossed inverted T-members to provide a continuous, linear air distribution means in the ceiling which is effectively uninterrupted by the intersections of the grid T-bars.

A typical suspended ceiling insulation employs main inverted T-runners, indicated generally at II), which are suspended from the above soffit or ceiling by conventional hanger wires ll. Cross inverted T-bars l2 span the distance between main runners l0, and are secured thereto in conventional manner, to complete the grid system which normally supports acoustical or other ceiling tiles 5.

As particularly contemplated within the present invention, a plurality of diffuser units, or air distribution subassemblies, indicated generally at 14, are mounted in a linear array transversely of and supported on the main T-bar members and straddling the cross T-bar members 12. In the foreground of FIG. 1, the subassemblies indicated generally at 14 are shown positioned above the grid prior to their assembly thereto, while the same type of assemblies 14 are shown assembled to the grid system in the background of FIG. 1. As seen in FIG. 2, when the air diffuser assemblies 14 are positioned with their opposite ends resting on the flanges of main runners 10, they straddle the centrally disposed cross T-bars 12 which form a part of the air diffuser means as hereinafter described.

Again referring to FIG. 2, each diffuser assembly 14 is an assembly of spaced sidewall members 16 and 16', the latter having upper flanges 17, 17', outwardly extending

midflanges

18, 18 and lower tile supporting flanges 19, 19', respectively. The upper flanges 17, 17' cooperate with the air supply duct, as subsequently described, while the midflanges 18, 18' and

upstanding rails

20, 20 cooperate in mounting the assemblies 14 to the main runners 10 as seen in FIG. 5.

Referring to FIG. 5, it can be seen that the ends of the air distribution subassemblies 14 are mounted to the main runners 10 by brackets 23, one leg of bracket 23 being received between midflange 18 and rail 20 while the other leg rests on main runner 10 and is held thereto by spring clip 24. The lower flanges, as flange 19, of the air distribution subassemblies 14 are maintained in the same plane as the bottom flange, as flange 21, of the main runners 10.

Referring to FIG. 4, it can be seen that the ends of the air distribution subassemblies 14 are slotted at 15 to straddle the vertical leg or web 12 of the cross T's 12. Also, as shown, the cross T's 12 may be secured by means of clips 12 to the main inverted T-bars 10.

Each air distribution subassembly is provided with an airstraightening core or louvred plate 25, as seen in FIGS. 2, 3 and 4 with a plurality of depending veins 26. Plate 25 is held between

sidewalls

16 and 16 by the closely spaced walls or

ribs

27, 27 as seen in FIG. 2. After assembly of an air duct over the plurality of air distribution subassemblies, as hereinafter explained, air moving horizontally above the diffusing units is extracted by plate 25, straightened by the veins 26 and passed downwardly between walls 16, 16' of the subassemblies in known manner. As best seen in FIG. 2, weir means in the form of exemplary nested U-shaped channel weir members 30, and 31, 31', as more fully disclosed in US. Pat. No. 3,41 1,425, are provided in the subassemblies between walls l6, 16 with the ends of the weir members slidably mounted in channel like recesses 28 formed in the end plates 29, as best seen in FIGS. 3 and 4. End'plates 29 are held between

sidewalls

16 and 16 by means of conventional fastening means, as metal screws 29', secured through the sidewalls to intumed ears or flanges, as ears 29", which are integral with end plates 29. The nested weir members or channel members 30, 31 and 30, 31' may be adjusted relative to one another to control the direction and amount of air distributed through the assemblies. In the position shown in FIG. 2, the air distribution from the openings in plate 25 is directed by the weir members against the lower flange of the centrally straddled cross inverted T-bar member 12 and thus outwardly generally adjacent the underside of the suspended ceiling surface in somewhat the manner disclosed and described with regard to the embodiments of air diffuser assembly of the second sheet of drawings of my prior US. Pat. No. 3,406,623. In the last-named patent, the inverted T-member is used as part of the air distribution assembly, as in the present case. However, the assembly or system of my prior U.S. Pat. No. 3,406,623 does not achieve the continuous linear air distribution system of the present invention.

As further contemplated within the present invention, a single continuous air supply plenum is mounted upon two or more adjacent air distribution subassemblies 14 as shown in FIGS. 1, 2 and 3. In the exemplary embodiment, such continuous air supply plenum includes the plenum chamber assembly,

indicated generally at 50, comprised of individual sections 51 which may be taped together into an effectively continuous duct by air sealing the joints therebetween. In the exemplary embodiment, tape 52 has been applied to a joint, indicated in dotted line at 53 to seal the ducts and make it effectively continuous. A particular run of duct may have closed ends, as shown at 54 in FIG. 1. A top inlet 55 may be provided with a cover plate 56 adapted to be seated thereon and providing an upwardly extending collar 57 to removably receive flex duct, as shown in dotted line at 58. The sidewalls 59, 59' of each duct unit are adapted at their lower ends to be mounted upon the linear array of air diffuser subassemblies as hereinafter explained.

As best seen in FIG. 2, the lower ends of the sidewalls 59, 59' of each duct section 51 have a reduced cross section to fit within resilient mounting channel-shaped

clips

60 and 60. Each

resilient channel clip

60, 60 is provided with a reentrantly folded footing portion, 61 and 61', respectively, and associated depending resilient finger portions 62 and 62', respectively, to facilitate a snap fit mounting of the continuous duct on the plurality of linearly arranged air diffuser subassemblies 14. As seen in FIG. 3, the mounting of a single continuous linear air supply duct over a plurality of diffuser subassemblies mounted and integrated into the preexisting ceiling system provides a continuous linear air distribution means in the ceiling which is effectively continuous across the intersection of a main inverted T-bar l0 and the auxiliary or cross inverted T-bars 12.

As will be explained in detail with regard to the following explanation of an alternative exemplary embodiment, any particular air diffuser subassembly 14, or part thereof, can be blanked off by spreading the weir means 14 to control the location of air distribution from the assemblies. Further, the ducting, or the connection between the ducting and the diffuser assemblies may be interrupted in order to allow the return of air through the assemblies 14 into the ceiling plenum.

Referring now to FIGS. 6 through 9, an alternative form of the exemplary embodiment of the suspended ceiling integrated air diffuser assembly in accordance with the present invention will be described.

In the exemplary embodiment of FIGS. 6 through 9, the alternative form of diffuser subassemblies 114 are suspended by means of hanger wires 111, as best seen in FIG. 6, to provide a linear continuous array thereof crossing spaced independently hung main ceiling support runners 110. In this embodiment, the air diffuser subassemblies do not straddle cross T-bars, as in the former assembly, but are complete air diffusers which can control the distribution of air through a ceiling in a continuous linear fashion crossing spaced main T-bars.

Referring to FIG. 7, the alternative exemplary embodiment of air distribution subassemblies 114 include a pair of spaced inverted T-bar members 116 and 116'.

Members

116, 116 are provided with top flanges-117, 117' midflanges 118, 118' and upstanding ribs 120 and 120' as in the prior embodiment to facilitate mounting of the air supply duct and the mounting of the assemblies in interlocked relation to the main bars, respectively. However, in the alternative embodiment of subassembly, the lower tile-supporting flanges 119 and 119' extend inwardly of the subassembly, at 121 and 121 respectively, to facilitate the directional control of air supply through the subassemblies as hereinafter explained.

Still referring to FIG. 7, it can be seen that a pair of nested weir means and 131 are provided with their respective ends slidably mounted in end plate channels, as channel 128 in plate 129 in FIG. 9. As seen in FIG. 9, the end plates 129, as in the case of the prior embodiment, have inwardly directed ears, as ear 129 which may be fastened to the subassembly sidewalls 116 and 116' by conventional fastening means, as

for example metal screws.

An extractor plate may also be provided on the top of the subassemblies 114 which also functions in mounting the air supply ducts thereon and the suspension of the assemblies via hanger wires 1 1 l.

Referring now to FIGS. 6 and 7, extractor plate means are provided in the form of inverted resilient channel members 125 having upwardly inclined extractor veins 126 positioned in the bottom outlet 151 of duct 150. In this embodiment, duct 150 may include a plurality of sections 152 which are joined by tape 153 and are provided with end closures 154. A single air supply duct 155 may be connected by suitable means, as

collared plate 156 to one of the duct sections for supplying air continuously to the plurality of subassemblies 114.

As seen in FIG. 7, the resilient inverted extractor plate channel 125 has depending

flanges

156 and 157 adapted to fit between the spaced sidewalls and may be held thereon by the provision of spring clips 158 and, 158'. The duct sections 152 may be secured'upon the upper surface of the inverted extractor channels 125 by provision of gasket means 159 and suitable adhesive between the channel 125, gasket 159 and duct sections 152.

Referring to FIG. 8, it can be seen that in the exemplary embodiment of FIG. 6, the centrally disposed air diffuser subassembly 114 is shown utilized as an air return for exhaust air from the air-conditioned room into the air return plenum above the ceiling. As shown in FIGS. 6 and 8, a plurality of spaced inverted channel-shaped spring clips 170 and 171 may .be mounted upon the subassembly, by means of side spring clips 172 and 173. The portion of the air supply duct 150 positioned over the air distribution subassembly 114' is preferably provided without any air distribution outlets so that it merely serves as a conduit in conveying air from the supply duct 155 to the outlying subassemblies. This portion may then be used for air return into the ceiling plenum in the spaces between the closed ducts and subassembly 114' as seen in F IG. 8.

From the foregoing detailed description of the alternative exemplary embodiment of FIGS. 6 through 10, it can be seen that a continuous linear air distribution system can be installed in a preexisting suspended ceiling system, in accordance with the present invention, without modifying the suspended ceiling grid support system, but yet still providing an effectively continuous linear air distribution system over extended lengths of ceiling surface. For example, the embodiment of FIGS. 6 through 10 could be extended for the entire ceiling length or width of a room with various portions of the effectively continuous linear air distribution subassemblies activated as air supply, air return or as closure members for a variety of air distribution functions in a linear path. The latter embodiment may then serve as crossbar support means for ceiling tile supported on the main runners 110 and the tile flanges 119, 119'. In this embodiment, the subassemblies are complete air distribution devices in themselves and do not require the use of the central air distribution T-member as in the first preferred exemplary embodiment.

From the foregoing detailed description of two alternative exemplary embodiments of a suspended ceiling integrated air distribution system, in accordance with the present invention, it can be seen that an effectively continuous linear air distribution system may be integrated into preexisting suspended ceiling systems in'accordance with the present invention. The air distribution subassemblies may be independently suspended adjacent ceiling support main runners to provide such linear continuous air distribution across the ceiling main runner supports or, as in the first embodiment, may be mounted upon the ceiling support main runners and, preferably, straddling the cross T-bar members to provide a truly integrated air distribution system in a preexisting suspended ceiling structure.

lclaim:

1. An interrupted, yet effectively continuous, air distribution assembly to be integrated into a preexisting suspended ceiling tile supporting grid of intersecting main and cross inverted T-bars, said assembly comprising:

a plurality of air diffuser subassemblies having spaced sidewalls and end walls defining an air distribution passage therebetween, each of said subassemblies extendsubassemblies form a linear array thereof extending transversely of pairs of spaced inverted T-bars each of which intersects and thereby interrupts the linear air distribution passage formed by said array of subassemblies; and

a continuous air supply plenum associated in air supply relation with two or more adjacent diffuser subassemblies of said plurality and having a continuous air supply outlet along a lower portion thereof extending above and across at least one or more of said T-bars intersecting said air distribution passage to provide an effectively continuous air distribution through said interrupted passage.

2. The interrupted, yet effectively continuous, air distribution assembly of claim 6 wherein:

said air supply plenum is mounted in air supply communication with at least three of four adjacent subassemblies of said plurality of air distribution assemblies, said fourth subassembly having its air distribution passage communicating between a first space outside said air supply plenum and above said ceiling system and a second space below said ceiling system into which air is supplied from said air supply plenum.

3. An air distribution assembly which is easily integrated into a preexisting suspended ceiling system having a grid of main and cross inverted T-bar members to provide a continuous linear air distribution means through said ceiling, said air distribution assembly comprising:

a plurality of air distribution subassemblies, each having spaced sidewalls defining an air distribution passage therebetween, said subassemblies being mounted in a linear array transversely of and supported on said main T- bar members and straddling said cross T-bars members; and

a continuous air supply plenum mounted upon two or more adjacent air distribution subassemblies of said plurality of subassemblies, said plenum having a continuous air supply outlet along a lower portion thereof extending across at least one intersection of a main T-bar, supporting two adjacent subassemblies, and the adjacent cross T- bars and in air supply communication with each air distribution passage of said last-named two subassemblies to provide effectively continuous air distribution through said ceiling across said intersection in said preexisting ceiling system.

4. The air distribution assembly of claim 3 wherein:

said air supply plenum is mounted in air supply communication with at least three of four adjacent subassemblies of said plurality of air distribution subassemblies, said fourth subassembly having its airdistribution passage communicating between a first space outside said plenum above said ceiling system and a second space below said ceiling system into which air is supplied from said plenum.

5. The air distribution assembly of claim 3 wherein:

the opposite ends of each of said air distribution subassemblies are slotted to straddle the vertical leg of the associated inverted cross T-bar, a bottom horizontal flange of each of said crossT-bars lying in the outlet path of the air distribution passage of the associated subassembly.

6. An interrupted, yet effectively continuous, air distribution assembly to be integrated into a preexisting suspended ceiling tile-supporting grid of intersecting main and cross inverted T-bars, said assembly comprising:

a plurality of air diffuser subassemblies having spaced sidewalls and at least partially open end walls to receive an upstanding leg of an inverted T-bar therethrough, said diffuser subassemblies being positioned in a linear array along and straddling one or more T-bars and being mounted at their respective ends on associated T-bars intersected by said one or more T-bars to provide air distribution passages between said spaced walls and divided by said one or more T-bars, said distribution passages extending along said array and being interrupted by said associated T-bars on which said subassemblies are mounted", and

3 7 7 9 O4 5 7 8 a continuous air supply plenum associated in air supply rela- 1 continuous air supply outlet along a lower portion thereof tion with two or more adjacent difiuser subassemblies of extending above said one or more T-bars and across at said plurality of air diffuser subassemblies and having a least one or more of said associated T-bars.

UNIT D STATE S PATE'N' OFFICE EBT F Q TE .QFMQQRRECTION;

Patent No. 3,572,204 a Dated M 11. 121i Inventpr Robert R. Lambert It is certified that error appears in the aboveidentified patent and that said Letters Patent is hereby corrected as shown below:

Claifn 2, line 2, delete "6", and insert --l-- Signed and sealed this 124th day of December 1971.

(SEAL) Attest: A I

EDWARD M.FLETCHER,JR. ROBERT GO'I'TSCHAUC Attesting Officer Acting Commissioner of Patents

Claims

1. An interrupted, yet effectively continuous, air distribution assembly to be integrated into a preexisting suspended ceiling tile supporting grid of intersecting main and cross inverted Tbars, said assembly comprising: a plurality of air diffuser subassemblies having spaced sidewalls and end walls defining an air distribution passage therebetween, each of said subassemblies extending between and being supported only at their opposite ends by a pair of spaced generally parallel inverted T-bars of said preexisting ceiling grid, whereby said plurality of subassemblies form a linear array thereof extending transversely of pairs of spaced inverted T-bars each of which intersects and thereby interrupts the linear air distribution passage formed by said array of subassemblies; and a continuous air supply plenum associated in air supply relation with two or more adjacent diffuser subassemblies of said plurality and having a continuous air supply outlet along a lower portion thereof extending above and across at least one or more of said T-bars intersecting said air distribution passage to provide an effectively continuous air distribution through said interrupted passage.

2. The interrupted, yet effectively continuous, air distribution assembly of claim 6 wherein: said air supply plenum is mounted in air supply communication with at least three of four adjacent subassemblies of said plurality of air distribution assemblies, said fourth subassembly having its air distribution passage communicating between a first space outside said air supply plenum and above said ceiling system and a second space below said ceiling system into which air is supplied from said air supply plenum.

3. An air distribution assembly which is easily integrated into a preexisting suspended ceiling system having a grid of main and cross inverted T-bar members to provide a continuous linear air distribution means through said ceiling, said air distribution assembly comprising: a plurality of air distribution subassemblieS, each having spaced sidewalls defining an air distribution passage therebetween, said subassemblies being mounted in a linear array transversely of and supported on said main T-bar members and straddling said cross T-bars members; and a continuous air supply plenum mounted upon two or more adjacent air distribution subassemblies of said plurality of subassemblies, said plenum having a continuous air supply outlet along a lower portion thereof extending across at least one intersection of a main T-bar, supporting two adjacent subassemblies, and the adjacent cross T-bars and in air supply communication with each air distribution passage of said last-named two subassemblies to provide effectively continuous air distribution through said ceiling across said intersection in said preexisting ceiling system.

4. The air distribution assembly of claim 3 wherein: said air supply plenum is mounted in air supply communication with at least three of four adjacent subassemblies of said plurality of air distribution subassemblies, said fourth subassembly having its air distribution passage communicating between a first space outside said plenum above said ceiling system and a second space below said ceiling system into which air is supplied from said plenum.

5. The air distribution assembly of claim 3 wherein: the opposite ends of each of said air distribution subassemblies are slotted to straddle the vertical leg of the associated inverted cross T-bar, a bottom horizontal flange of each of said cross T-bars lying in the outlet path of the air distribution passage of the associated subassembly.

6. An interrupted, yet effectively continuous, air distribution assembly to be integrated into a preexisting suspended ceiling tile-supporting grid of intersecting main and cross inverted T-bars, said assembly comprising: a plurality of air diffuser subassemblies having spaced sidewalls and at least partially open end walls to receive an upstanding leg of an inverted T-bar therethrough, said diffuser subassemblies being positioned in a linear array along and straddling one or more T-bars and being mounted at their respective ends on associated T-bars intersected by said one or more T-bars to provide air distribution passages between said spaced walls and divided by said one or more T-bars, said distribution passages extending along said array and being interrupted by said associated T-bars on which said subassemblies are mounted; and a continuous air supply plenum associated in air supply relation with two or more adjacent diffuser subassemblies of said plurality of air diffuser subassemblies and having a continuous air supply outlet along a lower portion thereof extending above said one or more T-bars and across at least one or more of said associated T-bars.