EP0389508B1

EP0389508B1 - Air distribution device

Info

Publication number: EP0389508B1
Application number: EP88909397A
Authority: EP
Inventors: Stig BJÄRKVIK
Original assignee: ABB Flaekt AB
Current assignee: ABB Technology FLB AB
Priority date: 1987-10-22
Filing date: 1988-10-24
Publication date: 1993-03-17
Anticipated expiration: 2008-10-24
Also published as: FI901952A0; WO1989003961A1; SE8704133D0; ATE87082T1; NO901748L; FI94670C; EP0389508A1; FI94670B; NO168137C; DE3879507D1; DK95090D0; DK95090A; NO168137B; JP2647478B2; DE3879507T2; NO901748D0; AU2602788A; SE8704133L; JPH03500678A

Abstract

An air distribution device (10) comprises an air inlet (12) which conducts incoming ventilation air (56), through a perforated distributing and throttling plate (32), to a distribution chamber (14) which is bounded on one side by a perforated front cover plate (24) of the device. Located inwardly of the front cover plate are guide rails (26) which are perpendicular to the incoming air flow and steer the exiting air in a first main direction. The device further comprises plates (30) which extend at right angles to the rails (26) and which function to support the guide rails and to guide the air exiting from the device in another main direction. The distributing end throttling plate (32) exhibits through-flow zones (34, 35, 36) with intermediate imperforate or constricted induction zones (38) on the downstream side of the plate, these zones being open towards a secondary air port (42) provided on the device.

Description

The present invention relates to an air distribution device of the kind set forth in the preamble of Claim 1.
The inventive air distributing device is a low impulse device and can either be built into or attached to a wall or like structure or may stand freely on a floor or like support surface. The device is located close to the floor and consequently the speed of the incoming air must be low, in order not to create draughts or other disturbing phenomena.
Previously known air distributing devices of this kind are encumbered with a number of drawbacks. The construction of the device is often unnecessarily complicated, which results in high manufacturing costs and time consumption, and also in high repair and maintenance costs. Furthermore, the exiting air flow is often not controlled satisfactorily, especially in the horizontal plane, which results in uneven ventilation in the room in which the device is placed. Quite often previously known air distribution devices suffer from high pressure of the incoming air in connection with small apertures in the distribution and/or partition surfaces of the device. Such small apertures become sooner or later clogged with impurities rendering a smaller flow of air and thus a non-desired mode of operation of the device. Regular cleaning and/or exchange of parts of the device will often be unavoidable, as see EP-A-0199762.
FR A 2 169 131 discloses a device without induction of secondary or room air, but with not less than three different perforated walls, through the small perforations of which the air has to be fed out under high pressure and thus entailing the draw-backs as mentioned before.
US A 1 523 268 discloses an air distribution system for ceilings, which system also lacks induction of secondary or room air, and in which there is no confinement of the various outlets to a single and coherent device. Neither is this system designed to be used in the lower area of a room as is the present invention.
Consequently, it is the object of this invention to provide an improved air distribution device in which the aforesaid drawbacks are substantially avoided, which is of simple construction, which will control the incoming air satisfactorily in both the vertical and horizontal directions, which incurs low manufacturing costs and repair and maintenance costs, and which represents a general step forward in this art. The invention aims also at saving energy and costs by making it possible to use less primary or ventilation air in the first hand and lower temperature of same in the second hand compared with previously knowndevices It is also an object of the invention to provide a better spread of the ventilation air, and to avoid the necessity of regular inspection, cleaning and/or exchange of parts of the device.
These objects are achieved with an air distribution device of the aforesaid kind which has the characterizing features set forth in the following claims, primarily in the characterizing clause of Claim 1. The device according to the invention requires a relatively low speed of the through flowing-air and ensures uniform ventilation of a major range surrounding the device. Secondary air is continuously sucked into the device, mixed therein with the primary air and fed out in a mixed and conditioned state. In a practical example, the secondary air has higher temperature than the primary air, which accordingly brings about a mixture of temperatures and allows thus lower temperatures of the primary air without a lower temperature of the distributed air mixture compared with a device without induction and other essential features according to this invention. In this way, costs for the air distribution and the apparatus creating same may be kept down, as smaller dimensions and lower temperatures may be applied. Even costs of operation may be reduced, as minor fans or minor efficiency of same will be required.
The device operates entirely without hydraulic, pneumatic or electric means, which often are sensitive to break-downs and have a limited life time. To equip the device with a distributing and throttling plate exhibiting through-flow zones with intermediate imperforate or constricted induction zones on the downstream side of the plate allowing induction of secondary or room air, is a surprisingly simple and efficient means for achieving partly an advantageous induction and partly contributing to the new and advantageous combined mode of operation of the device according to the invention.
The invention will now be described in more detail with reference to exemplifying embodiments thereof illustrated in the accompanying drawings, in which

Figure 1 is a partially cut-away perspective view of a first embodiment of the invention;
Figure 2 is a cross-sectional view taken on the line B in Fig. 1 and shows the device mounted in a wall structure;
Figure 3 illustrates an air distributing and throttling plate located at A in Figure 2;
Figure 4 is a horizontal view of the air distribution device taken on the line C in Figure 1;
Figure 5 is a partially cut-away perspective view of a second embodiment of the invention;
Figure 6 is an axial section of the air distribution device of Figure 5 and shows the air flows through said device;
Figure 7 is a horizontal section taken on the line E in Fig. 6 and shows guide rails and baffle and support plates included in the inventive device;
Figure 8 illustrates a second embodiment of an air distributing and throttling plate located at D in Figure 6;
Figure 9 is a partially cut-away perspective view of a third embodiment of the invention;
Figure 10 is a partially cut-away side elevational view according to line F./.F in Figure 11;
Figure 11 is a partially cut-away top plan view of the device accordning to Figures 9 and 10;
Figure 12 is a partially cut-away perspective view of a fourth embodiment of the invention;
Figure 13 is a top plan view of the device according to Fig. 12 without upper wall;
Figure 14 illustrates in an expanded view the mode of assembling guide rails and support plates according to Figures 12 and 13;
Figure 15 is a partially cut-away perspective view of a fifth embodiment of the invention;
Figure 16 is a partially cut-away front-view of the device according to Figure 15; and
Figure 17 is a view according to line K./.K in Figure 16.

Figures 1-4 illustrate a first embodiment of an inventive air distribution device 10 which is intended for mounting at or in a wall or like structure, e.g. a stud wall 1, indicated in chain lines in Figure 2, at a short distance above a floor surface 2. The device 10 is flat and includes an inlet sleeve 12 which extends to a distribution chamber 14 bounded by a rear wall 16, side walls 18, a bottom wall 20, and an upper wall 22 which is contiguous with the inlet sleeve. The distribution chamber 14 is covered on the side thereof facing the room to be ventilated with a perforated front cover plate 24 which has located centrally and inwardly thereof a distribution or screening plate 25 contributing to desired lateral diversion of a part of the outgoing air flow. Arranged inwardly of the plates 24 and 25 are horizontal guide rails 26, the rear edges of which are upwardly curved, as shown at 28. The rails 26 are carried by the side walls 18 or preferably, as shown, by vertical baffle and support plates 30 which are preferably inclined to the vertical so as to diverge in the direction of the outgoing air flow, and which are located on respective sides of the distribution plate 25 and have an outwardly angled part 31 at a location nearest the front plate 24. The baffle and support plates 30 and preferably also the guide rails 26 are provided with slots by means of which the plates and rails can be brought into mutual locking relationship. The plates 30 and/or the rails 26 may be arranged tiltable to allow modified setting.
Arranged between the inlet sleeve 12 and the distribution chamber, or box, 14 is an air distributing and throttling plate 32, which is perforated with holes 34. The holes are disposed in a rear row 35 and mutually parallell rows 36 said rows enclosing intermediate imperforate induction zones 38 which open toward the front side of the device. As indicated by the arrow 40 in Figures 2 and 3, induction air is drawn by suction into the induction zones on the downstream side of the distribution plate 32, from a secondary air aperture or port 42 directed towards the front side of the device. The secondary air aperture is bounded laterally by the side walls 18, upwards by the upper wall 22 and/or and upper boundary plate 44, and downwards by a lower boundary plate 46. This secondary air port, however, may be screened-off, e.g. by a displaceable co-planar or co-curved perforated plate, mesh or the like (not shown), when a reduced amount of secondary air or return air is to be taken from the ventilated room. This latter plate and plate 25 may also be combined to allow simultaneous setting of both areas in any desired way.
The front plate 24 is located at a distance from the wall 1 such as to leave an intermediate gap or slot 48. The plate 24 has at each end thereof a rearwardly bent side edge portion 50 which carries an inwardly turned flange or lip 52. Both the bent side-edge portions 50 and their respective corners joining the front plate and also the lips 52 have perforations 54 similar to the front plate. This avoids the occurrence of non-uniformly directed and sharply defined air exit zones on both the front side of the device and externally of the gap or slot 48. The holes 54 in the side-edge portions 50 and their respective corners assist in equilizing the gas or air flow in this region and also prevent the occurance of stagnation zones. The centrally located air distribution plate 25 is effective in throttling the air flow in the central region of the front plate. This air throttling effect together with the guiding effect afforded by the baffle and support plates 30, with their outwardly angled parts 31, assist in delivering air to regions which lie immediately in front of and laterally of the inventive air distribution device.
The modus operandi of the air distribution device 10 can be described briefly as follows: Air entering the device (arrow 56) from a conduit (not shown) is slowed down in the inlet sleeve 12 by the air distributing and throttling plate 32 and flows uniformly distributed down through the rear rows of holes 35, along the rear wall 16 of the distribution chamber and through the mutually parallel rows of holes 36. As a result hereof, a subpressure is generated on the underside of the plate 32 in the imperforate zones 38 and induction air is drawn into these zones in the aforedescribed manner. During the downward passage of the air through the distributing chamber 14, part air-flows are successively directed forwardly by the rails 26. The upwardly bent parts 28 of the rails 26 will therewith act as "splitters" and split off that part of the incoming air flow located nearest the front side of the device. The rear wall 16 is inclined and hence the chamber 14 narrows downwardly, so that the air will flow at essentially the same speed throughout the whole length of the chamber and air flows of equal size will be deflected or guided outwards through the front cover plate by the guide rails.
A wall-mounted air distribution device constructed in accordance with the invention is typically adapted for fitting to studwork in which the vertical studs are spaced 70 mm apart. To this end, the inlet sleeve is given conveniently a size of 60 x ca 500 so as to utilize all the space available between the studs. The device itself has a typical width of 600 mm and a height of 300-900 mm depending on the air requirement concerned. The diameter of the holes in the distribution plate 32 ranges from 8 to 16 mm, depending on the air requirement concerned. The front cover plate may suitably have a hole diameter of 5 mm with a centre distance of 7.5 mm. The device 10 is suitably placed at a distance of 10 cm from the floor.
Figures 5-8 illustrate another embodiment of the inventive device, referenced 110, which is intended to be placed freely on a floor or like support surface. Components which are similar or identical to corresponding components of the Figures 1-4 embodiment have been identified with the same reference signs, although with the addition of a prefix 1 (one).
The exemplifying device 110 illustrated in Figures 5-8 includes an inlet sleeve 112 which extends to a distribution chamber 114 which is bounded at the bottom by a bottom plate 120 and at the top by a top cover 122.
The device is supported on a floor base 123 and comprises an encircling cylindrical, vertical front cover which is perforated with holes 154 for the passage of ventilation air. Located within the front cover is a number of annular, horizontally oriented guide rails 126, the radially inner edge of each of which is bent upwardly around the centre hole 129 of the annulus, to form an upstanding collar 128. The annular rails 126 are carried by a plurality of vertical baffle and support plates 130 which are at least three in number, preferably four or more. The central hole of the annular guide rails 129 decreases in size with increasing depth and distance from the inlet sleeve 112, thereby to form a downwardly narrowing distribution chamber. The guide rails 126 and/or the vertical support plates 130 also in this case include slots by means of which the rails can be attached securely and reliably kept in position. The plates 130 function to support the annular guide rails 126 and also to guide the exiting ventilation air in the horizontal plane. Accordingly, when the need for such guidance is great, a large number of baffle and support plates 130 are provided. This may be the case, for instance, when the air distribution device 10 is intended to deliver ventilation only around a part of its circumference, while the remainder of the circumference is screened off by a screening plate (not shown) located in the immediate vicinity of the perforated front cover plate 124. In this case, the plates 130 are preferably located along the edges of such a screening plate.
As illustrated in Figure 5, the horizontal part of respective rails 126, and preferably also the collars 128 thereon, may be perforated with holes having a diameter of, e.g., 2 mm. These holes allow a certain amount of air to pass through the guide rail surfaces and guide rail collars. This prevents the occurence of subpressure zones on the underside of the guide rails and/or on the outside of the collars, in which zones back currents and turbulence may occur and therewith result in acoustic and flow disturbances in the flow exiting from the air distribution device.
The inlet sleeve 112 connects with an inlet box or chamber 131, the bottom of which is delimited by a distributing and throttling plate 132. The plate 132 has provided therein a plurality of through-passing holes 134 which are disposed in radially extending rows with intermediate inductions zones 138 which open outwardly towards the periphery of the device. Extending circumferentially around the device 110, beneath the plate 132, is a secondary air port 142 which is bounded at the top by an upper plate 144 (which also serves as the outer wall of the inlet box 131) and at the bottom by a bottom plate 146. Similarly to the first described embodiment, there is engendered on the undersida flows or currents 140 are drawn, through the secondary air ports 142. This suction of secondary air into the ventilation device may also be effected through the ejector effect created as a result of the speed at which the primary air flows into the device.
By drawing secondary air into the device in the afore-described manner, it is possible to increase the amount of air omitted from the device and therewith also the area or zone which can be effectively ventilated, while maintaining at a minimum the total amount of fresh air required from an external fresh air source. This will result in a reduction in the energy costs for transporting and heating the fresh air delivered to the device, and therewith minimize the total ventilation costs.
A free-standing air distribution device constructed in accordance with the invention need not necessarily be cylindrical, but may have any desired configuration. For example, the device may be triangular, square, rectangular or any other polygonal and/or irregular shape.
In the "corner" embodiment according to Figures 9-11, components which are similar or identical to corresponding components of the Figures 1-4 embodiment have been identified with the same reference numerals, although with the addition of a prefix 2. In a analogous way, the fourth and fifth embodiment show corresponding reference numerals with the addition of a prefix 3 and 4, respectively.
In Figures 9-11, between the side walls extending at a preferably right angle in relation to each other, there is an inclined rear wall 216, which prefereably is terminated by an upper inclined surface at approximately the same level as the lower boundary plate 246. In this case, the guide rail 226 have preferably straight front-edges, although the front cover plate 224 preferably is arcuated. The center part of the guide rails forms another straight edge abutting the distribution plates 225 and carrying same or vice versa. Instead of baffle or support plates, there are preferably only latteral limitations consistuted by the side walls of this device. It will be appreciated, that in this case any substantial latteral diversion of the outgoing mixed air flow is usually not necessary, as the side walls of this device are already flush with the adjacent walls of a room.
The embodiment shown in Figures 12-14 co-incides basically with the embodiment according to Figures 5-8. In this case, the vertical baffle and support plates 330 are, however, preferably arranged to support the entire central structure. On each level, two support plates 330 are preferably joined together with a guide rail 326 as shown in Figure 14, where the plates 30 are provided with centrally matching slots, meanwhile each guide rail forms around a central rectangular opening upwardly curved edges 328 leaving free recesses between one another to retain the support plates. As shown in Figure 13, the size of the central opening of the support rails decreases from top to bottom.
Finally, the fifth embodiment as shown in Figures 15-17 discloses a device of elongated semi-circular shape in cross-section. The interior of this device constitutes roughly a mirror-symmetrical combination of two devices according to Figures 9-11.
In the embodiments according to Figures 9-11 and 15-17, the central part of the front-edges and the latteral edges of the guide rails are preferably bent upwards or downwards to form flanges for attachment to the adjacent walls, respectively the distribution plates of the device. Furthermore, in all embodiments having distribution plates, these plates may preferably be combined with the guide rails, so that these parts may form a unit, preferably in combination with possible baffles or the like, which unit quickly and easily can be removed and installed. Also, as can be seen particularly in Figures 11 and 17, the straight front-edges of the guide rails in combination with a curved front plate facilitate equalization of pressure of the outflowing air mixture, which thus is distributed into a room as uniformly as possible. In the embodiments disclosing an inclined rear wall, this may, of course, be replaced by guide plates of downwardly increasing size as is the case with the fully circular embodiments.
It should be understood, that the guide rails also may be designed in one piece with the supporting structure, i.e. the lateral limitations, which may be support plates or baffles, namely by punching said guide rails out of a metal sheet. The supporting structure may be left to extend co-planar or co-curved with the front cover or may be bent to extend at any desired angle in relation to same. Naturally, such a unit may also be made of plastic material, prefetably by means of injection moulding.
It has to be stressed, that the guide rails shown in Fig.s 5 and 12 have a constant overall diameter but central openings with a diameter or dimensions which decrease from top to bottom, even if this may be difficult to see. Fig.s 6 and 13, respectively, do show clearly what is meant. Only with the provision of some central structure functioning like a rear wall 16 etc, the central openings may be of equal size throughout the device.

Claims

An air distribution device (10) comprising an air inlet (12) for primary or ventilation air (56), a distribution chamber (14), and a perforated distributing plate (25; 32) as well as a front cover plate (24) directed towards the surroundings and an air port (42) for sucking in secondary or room air, which is intended to be fed out through said cover plate with said primary air, characterized in that said distributing plate or one distributing plate (32) is provided between said inlet on the one side and said distribution chamber and said secondary air port on the other side, that this plate further is designed as a th rottling plate exhibiting throughflow zones (34) wiht intermediate imperforate or constricted induction zones (38) on the downstream side of the plate, which zones are provided adjacent and open towards said secondary air port for generating a subpressure on the underside of said plate and sucking in secondary air, that the distributing device further incorporates guide rails (26), the main surfaces of which extend substantially at right angles to the flow direction of the incoming air and being effective in guiding the mixed air exiting from the distribution chamber in a first main direction into a room, that said guide rails are exposed to said distribution chamber, and that said guide rails are supported by single or multiple lateral limitations, preferably plates (30) functioning as baffles, which limitations extend substantially at right angles to said guide rails and are further provided to guide and/or limit the lateral parts of the flow of air exiting from the device.
A device according to Claim 1, characterized in that the distribution chamber (14; 114; 214; 314; 414) decreases in cross-sectional area with increasing distances from the air inlet (12; 112; 212; 312; 412).
A device according to Claim 1, characterized in that the edge of respective guide rails (26; 126; 226; 326; 426) facing the distribution chamber (14; 114; 214; 314; 414) are configured with a part (28; 128; 228; 328; 428) which is angled towards the incoming air flows (56; 156; 256; 356; 456).
A device according to Claim 1, characterized in that the guide rails (26; 126; 226; 326; 426) and/or the angled rail parts have provided therein perforations such as to allow a given, limited amount of air to pass through to the leeward side of respective rails and respective angled rail parts.
A device according to Claim 1, characterized in that said through-flow zones have the form of mutually parallel rows (36) of holes or radially and outwardly extending rows of holes or the like (136; 236; 336; 436), which rows preferably extend from a rear or central, substantially uniterrupted row of holes (35).
A device according to Claim 1, characterized in that the cover plate (24) has a distribution or screening plate (25; 225; 425) located inwardly thereof facing the guide rails and/or the secondary air port (42; 242; 442).
A device according to Claim 1, characterized in that the baffle and support plates (30), preferably adjustably, diverge outwardly, towards said surroundings, to guide the air exiting from the device in a second main direction, and that the outer edges (31) of said plates preferably are angled into mutually opposite directions, and/or that said plates (30)are formed in one piece with said guide rails preferably by punching out the latter from a sheet of metal, said plates (30) extend in a plane co-planar or co-curved with said front cover plate (24) or being bent to include any desired angle in relation to said front cover plate.
A device according to Claim 1, characterized in that the device is substantially rectangular in cross-sectional shape and with its front plate (24) preferably located at distance from a rear mounting surface, i.e. a wall (1), such as to leave intermediate gaps or slots (48) which, preferably in combination with lateral openings in side edge portions (50) of the cover plate, allow an additional lateral flow of outgoing mixed air.
A device according to Claim 1, characterized in that the device (110; 310) is substantially circular in cross-sectional shape and intended to be placed freely on a floor or like support surface (2), the support rails (126; 326) being circular or polygonal at their exterior and interior edges,the central openings so formed by the interior edges increasing in size from top to bottom of the device, or being uniform with a downwardly sloping central structure (16) inserted in the throughgoing central opening of the device, preferably the guide rails leaving recesses between adjoining bent up interior edges (328) for receiving support plates (330) which are joined together with matching central slots and form a supporting cross at each level.
A device according to Claim 1, characterized in that the device (210; 410) is substantially quarter- or semi-circular in cross-sectional shape, the guide rails (226; 426) having trapezoi-dal shape with the central front edge part adjoining a distribution plate (225; 425), the lateral edges and/or the edges adjoining said distribution plate being bent upwards or downwards to form mounting flanges, a downwardly sloping rear wall structure (216; 416) being inserted between the side walls of the device respectively between the latter and an intermediate wall (430).