US3699871A

US3699871A - Supply air device for injection of preferably cold ventilation air

Info

Publication number: US3699871A
Application number: US119091A
Authority: US
Inventors: Birger Larkfeldt
Original assignee: Svenska Flaktfabriken AB
Current assignee: Svenska Flaktfabriken AB
Priority date: 1970-02-26
Filing date: 1971-02-26
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24
Also published as: CA937805A; JPS545224B1; DE2106394A1; SE351287B; NL7102599A; FR2083111A6; GB1317864A

Abstract

An air supply device adapted to be mounted adjacent one edge of a hung ceiling for injecting cold air from a duct extending parallel to the ceiling surface above the hung ceiling. The device consists of a pressure box having an air distribution chamber in its bottom formed between a pair of perforated plates which operate to distribute the air vertically downward and eliminate any horizontal component generated in the duct. To avoid the fouling of the ceiling surface surrounding the distribution chamber and the room wall adjacent the edge of the ceiling by the dirty secondary room air, air flow gaps are provided on three sides of the distribution chamber to inject air streams substantially parallel to the ceiling surface radiating outwardly from the distribution chamber, the outward flow deflecting the downwardly directed air by ejection and away from the room wall. Air flow regulating means are provided in each gap and in the distribution chamber to insure mixture of the air with secondary room air so as to avoid the draughts normally experienced from cold air inlet grilles.

Description

United States Patent Larkfeldt 1 Oct. 24, 1972 [54] SUPPLY AIR DEVICE FOR INJECTION 0F PREFERABLY COLD Primary Examiner-William E. Wayner VENTILATION AIR Att0rneyl-lowson & Howson [72] Inventor: Eirger Larkfeldt, Barnarp/Jonkop- [57] ABSTRACT mg, Sweden An air supply device adapted to be mounted adjacent {73] Asslgnee: Akt'ebolaget Svenska Flaktiabrlken one edge of a hung ceiling for injecting cold air from a Stockholm Sweden duct extending parallel to the ceiling surface above [22] Filed: 26, 1971 the hung ceiling. The device consists of a pressure box 21 Appl. No.: 119,091

[30] Foreign Application Priority Data Feb. 26, 1970 Sweden ..2478/70 [52] US. Cl. ..98/40 D, 98/1 10 [51] Int. Cl. ..F24f 13/06 [58] Field of Search....98/40, 40 D, 114, 121 R, 112,

98/110, 40 V, 40 VM, 41

[56] References Cited UNITED STATES PATENTS 3,511,162 5/1970 Truhan ..98/115 X 3,380,372 4/1968 Perry ..98/40 V X 2,544,689 3/1951 Kennedy ..98/4O V having an air distribution chamber in its bottom formed between a pair of perforated plates which operate to distribute the air vertically downward and eliminate any horizontal component generated in the duct. To avoid the fouling of the ceiling surface surrounding the distribution chamber and the room wall adjacent the'edge of the ceiling by the dirty secondary room air, air flow gaps are provided on three sides of the distribution chamber to inject air streams substantially parallel to the ceiling surface radiating outwardly from the distribution chamber, the outward flow deflecting the downwardly directed air by ejection and away from the room wall. Air flow regulating means are provided in each gap and in the distribution chamber to insure mixture of the air with secondary room air so as to avoid the draughts normally experienced from cold air inlet grilles.

6 Claims, 3 Drawing Figures PATENTED URI 24 I972 FIGS.

- lNVENTORI BIRGER LARKFELD bawdaW/f ATTYS.

SUPPLY AIR DEVICE FOR INJECTION OF PREFERABLY COLD VENTILATION AIR This invention relates to a special embodiment of the supply air device described in my US. Pat. No. 3,631,788 for injecting preferablycold ventilation airinto rooms required to be draught-free in the dwelling zone. Said devices comprises a pressure box mortized in the ceiling and connected to a duct system for the supply of ventilation air. The pressure box is downwardly defined by and communicates with the room through an air distribution means comprising two perforated metal sheets mounted substantially horizontally somewhat spaced from each other and so arranged, that the sheets together'with side walls along their edges enclose a distribution chamber for the elimination of obliquely directed speed components and thereby to effect a uniform distribution of the air stream passing through said sheets. The air distribution means further includes gaps disposed around the perforated sheets outside said side walls, which gaps are provided with dampers for controlling the air amount flowing through the gap in question and adapted at opened dampers to inject air veils substantially in parallel with the ceiling surface of the room.

Supply air devices according to the invention and aforementioned patent specification are primarily intended for injecting cold ventilation air into rooms having a permanent cooling demand. Such rooms may be, for example, large-space office rooms requiring cooling all the year because of the heat emission from lighting fittings and persons, or such rooms which are surrounded on all sides by rooms heated in the wintertime and including such heat sources that the rooms require cooling even on the coldest days of the winter.

The supply air device according to said patent specification, however, preferably is intended to be placed in the ceiling in the inner parts of the room where the air is desired to be distributed substantially uniformly to all directions. The present invention, however, relates to a variant of said supply air device for use at the outer parts of the room, preferably adjacent the outer walls. The supply air device, which is intended for use in rooms with a sub-ceiling, further shall be adapted to be mortized in ceilings provided with rectangular, possibly soundproof slabs having the size of, for example, 300 X 600 mm, i.e., corresponding to half a ceiling slab. It is desired to be able so to direct the air injected into the room that a favorable air distribution is obtained, and simultaneously to avoid blowing of air against the wall.

The present invention, which has as its object to meet these special requirements, is characterized in that one of said gaps is provided with a plurality of damper blades arranged to the side of each other and adapted individually to be turned into different directions about a vertical axle, that the side 'of the supply air device opposed to said gap is closed, and that each of the gaps disposed along the remaining sides of the device is provided with a damper blade adapted to be turned about a horizontal axle. By means of the upright damper blades, the throw length and direction of the air jet directed to the room can easily be controlled. I

One usual setting of the damper blades is to direct them at the same angle to the center line. Another usual setting is to direct the damper blades in one half of the device at one angle and the remaining blades at another angle to the center line. By these adjusting possibilities the air jet can be directed at the desired angle to the center line, and it also can be directed in a diverging or converging'way.

An expedient embodiment of the invention is characterized in that the uppermost of the two perforated metal sheets has a considerably smaller perforationdegree, i.e., it is given an area permeable to air which is smaller than that of the lower sheet, preferably only one fifth of the perforation degree of the latter. This improves additionally the capability of the air distribution means to eliminate the detrimental effect of the dynamic pressure in the pressure box on the air distribution in the air.

The uppermost of the two perforated sheets preferably is provided with means for variably screening off the perforation apertures and thereby to vary the perforation degree of said sheet. The screening can be effected, for example, by means of a similar perforated sheet mounted movably adjacent the uppermost perforated sheet according to above, or by means of exchangeable unperforated sheets provided with one large opening of a size different for each of said exchangeable plates.

For preventing the air veils ejected out of the gaps around the perforated sheets from sweeping the ceiling surface immediately adjacent the device and by room air co-ejected with the veils to dirty said surface, the gaps can be defined toward the ceiling surface by an edge plate projecting from the ceiling surface.

The invention is described in greater detail below, with reference to the accompanying drawing showing by way of example a supply air device for applyingthe idea of the invention.

FIG. 1 shows a cross-section of the supply air device inserted in a sub-ceiling structure,

FIG. 2 shows a section through the supply air device along the line 11-11 in FIG. 1, and

FIG. 3 shows a section through the supply air device along the line IIIIII in FIG. 1.

In the drawing, the supply air device according to the invention is designated by 1. The device comprises a pressure box 4 mortized in the sub-ceiling 3 of a room 2 and connected to a duct system for the supply of the ventilation air via an air passageway 5. The pressure box is defined downwardly by and communicates with the room 2 through an air distribution means 6. According to the invention, said distribution means 6 comprises two perforated metal sheets 7 and 8, which are mounted horizontally somewhat spaced from each other and arranged so as together with side walls 9 along their edges to enclose a distribution chamber 10. Around three of the side walls 9 two opposed gaps 11 and one gap 21 are located, of which the gap 21 preferably is turned inwardly to the room and provided with a plurality of damper blades 18 arranged to the side of each other and adapted individually to be turned to different directions about a vertical axle for controlling the flow direction and throw length of the air jet 20. The side of the device which is opposite to said gap 21 is closed by a metal sheet 19. As this side preferably is intended to be placed very closely to an outer wall, no air will be blown against this wall. Each of the gaps 1 1 along the two remaining sides is provided with a damper blade 12 adapted to be turned about a horizontal axle and at opened dampers to inject air veils 13 substantially along the ceiling surface 3a of the room. The distribution chamber is intended to effect a uniform distribution of the air stream 14 passing through the perforated sheets 7 and 8, and further to eliminate in said air stream obliquely directed speed components originating from the dynamic pressure in the air stream supplied through the air passageway 5. The dampers 12 are intended to control the air amount 13 flowing through the gap 11 in question, and the object of the damper blades 18 is to control the direction of the air jet 20 passing through the gap 21. It is hereby possible to adjust in a simple way the flow pattern in the room 2 and so to direct the ventilation air, that it does not give rise to draught in the room. The cold air stream 14 injected downwardly through the perforated sheets 7 and 8 is ejected together with the air veils 13 injected through the gaps 11 and by the air jet injected through the gap 21. The cold air stream, thus, is kept away from the dwelling zone, and the entire air amount injected is caused to flow along the ceiling surface 3a to which the air streams are attracted. Owing to the energy losscaused by the deflection and 'co-ejection of the downwardly injected air stream 14, the air veils 13 are given a short throw length. Room air is also co-ejected (see arrows 15), but owing to the downwardly injected air stream 14 the room air is prevented from sweeping and dirtying the device 1 and the ceiling surface 3a around the same. The uppermost perforated sheet 7 has a degree of perforation considerably smaller than that of the lowermost perforation sheet 8, in order to ensure that the obliquely directed speed components caused in the air flowing through the perforated sheets 7 and 8 by the dynamic pressure in the pressure box 4 are eliminated prior to the injection into the room 2. A ratio 1:5 between the perforation degrees of the uppermost sheet and lowermost sheet has proved to render the best results.

In certain cases it may be suitable to make the airpermeable area of the uppermost perforated sheet 7 adjustable. This can be effected in different ways. In FIG. 1, the dashed lines indicated an exchangeable metal sheet 16 provided with holes for variably screening off the perforation apertures in the perforated sheet 7.

For preventing the air veil 13 ejected out of the gap 11 in question from sweeping the ceiling surface in the immediate vicinity of the device 1, the gaps 11 are defined toward the ceiling surface 3a by a folded edge plate 17 projecting from the ceiling surface. The ventilation air injected, it is true, usually is filtered, but also the remaining dust particles and the dust particles from the co-ejected room air are prevented from appreciably dirtying the ceiling surface, because they are spread by the edge plate over a greater area before they meet the ceiling.

An exemplifying embodiment of the invention has been described with reference to the drawing. The invention can, however, be varied as to its details within the scope of the following claims.

I claim:

ing adjacent said wall for receiving the air supply device, said device comprising a pressure box positione'd above the plane of the ceiling surface and having a cold air duct connected thereto through one side thereof so as to introduce air into said pressure box from a direction parallel to the ceiling surface, said pressure box being mounted in said opening in said ceiling and having a lower portion comprising an air distribution means for introducing cold air from said pressure box into the room, said air distribution means comprising a pair of vertically spaced perforated plates disposed parallel to the plane of the ceiling surface, and side walls surrounding said pair of plates and disposed intermediate said plates to define a distribution chamber below said pressure box which eliminates any lateral component of air flow from the air duct to thereby uniformly direct the air flow from said distribution chamber vertically downward into the room for mixture with the secondary room air, one of said side walls of said distribution chamber .confronting said room wall being connected to the corresponding side of the pressure. box to preclude air flow therebetween toward said wall, the opposite chamber side wall furthest from said room wall being spaced from the corresponding side of said pressure box to provide an air flow gap alongside said distribution chamber, individually'adjustable upright vanes providing guiding surfaces in said gap for directing air flow from said pressure chamber outwardly from said air supply device substantially parallel to the ceiling surface of the room to provide an air veil to prevent flow of secondary room air along the ceiling surface alongside said device, and to deflect by ejection the downwardly. directed flow from said distribution chamber.

2. An air supply device according to claim 1 wherein the perforation of the upper of said pair of plates provide an air flow area about one-fifth of the area of the perforations of the lower of said plates.

3. An air supply device according to claim 1 including means cooperable with the perforated plate to variably screen off the air flow openings therethrough.

4. An air supply device according to claim 1 wherein said pressure box between said opposite side walls of the distribution chamber has 'edge plates depending below the ceiling surface and confronting the corresponding side walls of said distribution box in spaced relation to cooperate with said side walls to provide side gaps to direct the air sideways from said pressure box at a level spaced below the ceiling surface immediately adjoining said air supply device.

5. An air supply device according to claim 4 including horizontal damper means in said side air gaps to control the force of the air discharged through said gaps selectively.

6. A device according to claim 5 wherein said opening is rectangular and said air gaps comprise three gaps disposed along the respective sides of the rectangular openings, said horizontal damper means including a separate flap valve in each side gap.

Claims

1. A device for supplying cold air into a room having an upright wall and a sub-ceiling surface with an opening adjacent said wall for receiving the air supply device, said device comprising a pressure box positioned above the plane of the ceiling surface and having a cold air duct connected thereto through one side thereof so as to introduce air into said pressure box from a direction parallel to the ceiling surface, said pressure box being mouNted in said opening in said ceiling and having a lower portion comprising an air distribution means for introducing cold air from said pressure box into the room, said air distribution means comprising a pair of vertically spaced perforated plates disposed parallel to the plane of the ceiling surface, and side walls surrounding said pair of plates and disposed intermediate said plates to define a distribution chamber below said pressure box which eliminates any lateral component of air flow from the air duct to thereby uniformly direct the air flow from said distribution chamber vertically downward into the room for mixture with the secondary room air, one of said side walls of said distribution chamber confronting said room wall being connected to the corresponding side of the pressure box to preclude air flow therebetween toward said wall, the opposite chamber side wall furthest from said room wall being spaced from the corresponding side of said pressure box to provide an air flow gap alongside said distribution chamber, individually adjustable upright vanes providing guiding surfaces in said gap for directing air flow from said pressure chamber outwardly from said air supply device substantially parallel to the ceiling surface of the room to provide an air veil to prevent flow of secondary room air along the ceiling surface alongside said device, and to deflect by ejection the downwardly directed flow from said distribution chamber.

4. An air supply device according to claim 1 wherein said pressure box between said opposite side walls of the distribution chamber has edge plates depending below the ceiling surface and confronting the corresponding side walls of said distribution box in spaced relation to cooperate with said side walls to provide side gaps to direct the air sideways from said pressure box at a level spaced below the ceiling surface immediately adjoining said air supply device.