LIGHT FITTING INCLUDING FILTER ELEMENTS

Abstract: A light fitting in the form of a casing (1) which comprises a frame portion (2) defining an opening to a cavity (4) in the casing and which has one or more sockets (12) adapted to receive exchangeable light-producing members (13), especially fluorescent tubes, inside the cavity. One or more connectors are provided inside the casing (1) for connecting at least one exchangeable air filter tube (15) which can be arranged in the cavity and which has at least one air-permeable wall for cleaning the air conducted therethrough.

Description: LIGHT FITTING INCLUDING FILTER ELEMENTS. Brief description of the inventive idea The present invention relates to a light fitting in the form of a casing which comprises a frame portion de¬ fining an opening to a cavity in the casing and which has one or more sockets adapted to receive exchangeable light- producing members, especially fluorescent tubes, inside the cavity, said fitting comprising at least one air fil- ter for cleaning the air conducted therethrough. Description of prior art DE-A-2,428,568 discloses a light fitting of this type, in which the filter consists of a layer of filter medium fitted into the lower edge of an annular slit form- ed between an outer and an inner screen which together en¬ close and define the inner cavity of the fitting. It is not apparent from this specification whether the filter medium layer is exchangeable or not, but because of its position mounting and dismounting said layer would clearly require much time and effort. Summary of the invention The object of the present invention is to make it possible to exchange, in a simple and a convenient manner, the filter or filters used in said fitting. According to the invention, this is achieved in that the filter is a tube with at least one air-permeable wall, and that one o more connectors are provided inside the casing on the in¬ ner side of the frame portion for connecting one or more filter tubes which, like the light-producing members, are mounted inside said cavity. Thus, the filter tubes are easily accessible and can be exchanged in same manner as the fluorescent tubes or lamps in the fitting, a procedure with which the user usually is well acquainted. Brief description of the drawings In the drawings, FIG. 1 is a perspective view of a fitting according to the invention, seen obliquely from below, FIG. 2 is a cross-section of the fitting according to the invention, FIG. 3 is a part sectional top plan view of the fitting, and FIG. 4 is a longitudinal cross-section of an alternative embodiment of the fitting according to the inven¬ tion. Detailed description of a preferred embodiment of the in¬ vention The fitting shown in the drawings has the form of a casing which in its entirety is designated 1 and which, in the embodiment shown in Figs. 1-3, comprises a frame por¬ tion generally designated 2 and a bottom generally desig¬ nated 3. Together with the bottom 3, the frame portion 2, which in the embodiment in Figs. 1-3 is rectangular, de- fines a cavity 4 which has a downwardly facing opening 5. Both the frame portion 2 and the bottom 3 have interior and exterior walls 6, 7 and 8, 9, respectively. Together with a flat, frame-shaped wall 10, these interior and ex¬ terior walls 6, 7, 8 and 9 define a gap 11 common to both the frame portion and the bottom. Sockets 12 are disposed adjacent to the interior walls 6' forming the end walls of the cavity 4 and are adapted to receive light-producing members in the form of fluorescent tubes 13. In actual practice, both the sockets 12 and the fluorescent tubes 13 may be entirely conventional. Furthermore, holes 14 are arranged in the end walls 6' and serve to connect filter tubes 15. To be more precise, each end wall 6' comprises two holes, so that two filter tubes can be inserted in the cavity 4. In actual practice, the filter tubes 15 may ad- vantageously be of the type described in SE 8505171-2 and comprising a cylindrical, air-permeable wall consisting of creased and stiff paper. The tube is open at its two oppo- site ends, and strips 16 are attached to each of the tube openings and extend into the tube. As is best seen in Fig. 2, the centre axes of the holes 14 adapted to receive the filter tubes 15 are locat- ed farther inwardly from the opening 5 of the frame por¬ tion than are the sockets 12 for the fluorescent tubes 13. Thus, the centre axes of the sockets 12 are situated in a plane separate from that of the centre axes of the holes 14. A screen, in its entirety designated 17 and separating the fluorescent tubes from the filter tubes, is arranged in the area between the holes 14 adapted to receive the filter tubes and the sockets 12 for the fluorescent tubes. To be precise, the sockets are situated in the centre of the cavity, while the holes 14 are situated near to the long side edges of the cavity, such that the filter tubes will be located beside the screen for the fluorescent tubes. Advantageously, the screen 17 has the form of a downwardly open trough, the opening of which may be co¬ vered by a conventional grating 18 for light fittings. The opening 5 to the filter tubes 15 may also advantageously be covered by a grating 19 concealing the filter tubes. In the embodiment shown in Figs. 1-3, the filter tubes 15 serve as air supply devices for supplying cleaned supply air to the room where the fitting is mounted. For this purpose, an air supply line 20 runs to the fitting and is connected with an inlet 21 in the exterior wall 9 of the bottom 3. Another possibility is to connect such an air supply line with inlets 21' arranged in the exterior wall of the frame portion 2, as indicated by dash-dot lines in the Figures. In actual practice, one may, when manufacturing the fitting, arrange such inlets 21 in the exterior wall 9 of the bottom, as well as in the four ex¬ terior walls 8 of the frame portion 2, and then, in the final assembly, close those inlets that will not be used for connection with a line, e.g. by means of simple lid members. The air blown into the gap 11 through the line 20 is distributed in said gap and enters into the filter tubes 15 through the opposite openings thereof, whereupon it is filtered through the walls of the filter tube, such that the air, when entering the room where the fitting is mounted, is free from contaminating particles, such as dust, grime and the like, of the type found in air enter¬ ing, for instance, a room facing a busy street. Although the screen 17 shown in Fig. 2 is made of a wall impermeable to air, it is also possible to use a per¬ forated screen allowing air to pass into the space defined by said screen and circulate round the fluorescent tubes 13, so that no dust will adhere to and be burnt by said tubes. Naturally, particle-free air from the filter tubes 15 is circulated round the fluorescent tubes also if the screen is dispensed with. In actual practice, it is, how¬ ever, advantageous to mount such a screen round the fluor¬ escent tubes since the inside thereof may be provided with a light-reflecting layer. The filter tubes in the fitting may, of course, also serve as air exhaust devices for evacuating spent air from the room below. In this case, the direction of the air flow is simply reversed, such that air is sucked out of the gap 11 through a line 20 serving as evacuation line. Fig. 4 illustrates an embodiment serving as air exhaust device in which the cavity 4' of the casing 1' is, by means of two partitions 22, 22' , divided into three cham¬ bers 23, 24 and 25, the first of which contains one single filter tube 15' . The chamber 23 containing the filter tube 15' is covered from one end to another by an air-permeable plate 26, air-permeable gratings 27 being arranged at the openings to the cavities 24, 25. Thus, exhaust air from the room below is sucked in via the gratings 27, through the filter tube 15', and is finally sucked out of the chamber 23 through the line 20' serving as outlet. In the embodiment shown in Fig. 4, one or more fluorescent tubes 13' are intended to be mounted in separate partitioned-off spaces in the casing, on both sides of the chambers 23-25 which are in line with one another. In actual practice, the filter tubes 15 may be mount¬ ed and held in a very simple manner, in that their end walls are provided with flexible sealing rings, e.g. of rubber, which are compressed when the filter tube is in¬ serted from below, between the two opposite end walls 6' , such that said rings are sealingly applied against the end walls. Thus, the filter tubes become easily accessible and can readily be exchanged. Modifications of the invention It goes without saying that the invention is not re¬ stricted to the embodiment described above and shown in the drawings. For example, it is possible to dispense with the bottom 3 and have only the frame portion 2 in the form of a double-jacketed casing, in which case holes 21' for the air lines can be arranged only in the frame portion. Furthermore, the fitting may be adapted for other light- producing elements than fluorescent tubes, e.g. light bulbs, and the number of light-producing members therein may vary considerably. In the same way, the number of fil¬ ter tubes may vary materially within the scope of the in¬ vention. Also, other filter tubes than those open at its opposite ends may naturally be used. As is apparent from Fig. 2, the embodiment shown is adapted to be countersunk in a ceiling or in a wall. Naturally, the fitting may also be arranged on the outside, such that the bottom or the frame portion is applied against the ceiling or the wall. It should be pointed out that the geometrical shape of the casing need not be rectangular, but may for instance just as well be circular, polygonal or triangular.

Claims: CLAIMS 1. A light fitting in the form of a casing (1) which comprises a frame portion (2) defining an opening (5) to a cavity (4) in said casing and which has one or more sockets (12) adapted to receive exchangeable light-produc¬ ing members (13), especially fluorescent tubes, inside the cavity, said fitting comprising at least one air filter for cleaning the air conducted therethrough, c h a r a c ¬ t e r i s e d in that said filter is a tube (15) with at least one air-permeable wall, and that one or more connec¬ tors (14) are provided inside the casing (1) on the inner side of the frame portion for connecting one or more fil- ter tubes which, like the light-producing members (13), are mounted inside said cavity (4). 2. Light fitting as claimed in claim 1, c h a ¬ r a c t e r i s e d in that the frame portion (2) has se¬ parate interior and exterior walls (6, 8) defining a gap (11), thus forming a double-jacketed casing. 3. Light fitting as claimed in claim 2, c h a ¬ r a c t e r i s e d in that the casing (1) comprises, in addition to the frame portion (2), a bottom (3) at a dis¬ tance from the opening (5), and that the frame portion and the bottom (3) have separate interior and exterior walls (6, 7; 8, 9) defining a gap (11) common to both the frame portion and the bottom, thus forming a double-jacketed casing. 4. Light fitting as claimed in any one of the preced- ing claims, c h a r a c t e r i s e d in that two spaced-apart connectors (14) are disposed inside said cas¬ ing (1) and adapted to jointly receive a filter tube (15) which, in a manner known per se, is open at each of two opposite ends. 5. Light fitting as claimed in any one of claims 2-4, c h a r a c t e r i s e d in that an inlet (21) is ar¬ ranged in the exterior wall (8, 9) of the frame portion (2) and/or the bottom (3), and adapted to receive an air supply line (20) by means of which air from outside can be supplied to the inside of the filter tube (15) for passing out through the filter wall, said filter tube serving as air supply device (20) for introducing filtered supply air into the room where said fitting is mounted, more pre¬ cisely via the opening (5) in the casing. 6. Light fitting as claimed in any one of claims 2-4, c h a r a c t e r i s e d in that an outlet (21) is ar- ranged in the exterior wall (8, 9) of the frame portion (2) and/or the bottom (3), and adapted to receive an air evacuation line (20) by means of which filtered air, which has entered through the wall of the filter tube, can be evacuated via the gap (11). 7. Light fitting as claimed in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that the con¬ nectors (14) for the filter tubes (15) are located farther inwardly from the opening (5) of the frame portion than are the sockets (12) for the light-producing members (13), such that said members are located in a plane separate from that of said connectors. 8. Light fitting as claimed in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that a screen (17) separating the light-producing members from the fil- ter tubes is disposed in the area between the connectors for the filter tubes (15) and the sockets for the light- producing members (13).

Inventors: KRANTZ ANDERS, KRANTZ, ANDERS
Applicants: SOEDERHAMN ARCHITECT AB, AIRCHITECT I SOEDERHAMN AB
Application year: 1990
Main classification: F24F13
IPC codes: B01D46, F21V33, F24F3, F24F13