Lighting Fixture

Abstract

Fluorescent tubes are cooled by contacting the upper part of the cylindrical surface of such tubes with a contact member heat conductively associated with a cooling device. This device preferably consists of tubular contact members having a part-cylindrical concave surface for contacting the fluorescent tubes and inserted in a circuit for circulating cooling water through the tubular contact members. These contact members are mounted in a channel-shaped housing, heat conductivity associated therewith, and the fluorescent tubes are mounted in the same housing by spring actuated sockets adapted to urge the fluorescent tubes upwardly into contact with the concave surface of the tubular cooling members.

Description

This invention relates to lighting fixtures for mounting fluorescent tubes and accessories pertaining to such tubes and, more particularly, to fixtures comprising a cooling system adapted to absorb and recuperate the heat dissipated from the fluorescent tubes.

The main object of the invention is to provide simple, efficient and inexpensive means for removing excessive heat from rooms wherein fluorescent tubes are used as the light source and wherein illumination of great intensity and consequently a relatively large power consumption are required.

A further object of the invention is to provide means for recuperating the heat absorbed by the cooling system and using it during the cold season for heat distribution through conventional heat exchangers, such as radiators or, more particularly, through radiant heating sub-ceilings or panels.

Other and ancillary objects of the invention will appear from the following description with reference to the accommpanying drawings.

The basic feature of the invention consists in contacting a part of the cylindrical surface of the fluorescent tubes with a contact member of a material having a high heat conductivity and combining said contact member with cooling means capable of removing heat dissipated from the cylindrical surfaces of the fluorescent tubes.

In the drawings:

FIG. 1 is a perspective view, partly in cross section, showing a preferred embodiment of the lighting fixture according to the invention;

FIG. 2 is a cross section of a combined contact and cooling member for a lighting fixture according to the invention;

FIG. 3 is an end view, partly in cross section, of the fixture shown in FIG. 1;

FIG. 4 is a side view of the fixture shown in FIGS. 1 and 3 with one of the side walls partly removed;

FIG. 5 is an end view similar to FIG. 3 of a modified embodiment of the fixture;

FIG. 6 is a top view showing the construction of a cooling unit for a lighting fixture according to FIGS. 1, 3 and 5;

FIG. 7 is an end view of the structure shown in FIG. 6;

FIG. 8 is a schematic and simplified diagram showing a plurality of series connected lighting fixtures inserted in a heat pump circuit.

The fixture of the invention comprises an elongated, substantially box-shaped, downwardly opening housing 10 having a top wall 11 and downwardly projecting side walls 12 defining a lengthwise extending channel 10a of rectangular cross section. The side walls 12 may be provided with flanges 12a for mounting a cover plate 11a made of translucent material, such as acrylic resin adapted to close the open face of the housing opposite the top wall 11.

The housing 10 comprising top wall 11 and side walls 12 is made of a metal having a high heat conductivity, preferably of aluminium or an aluminium alloy, and mounted on the inner face of the top wall 11 and extending in the lengthwise direction of the housing 10 are a pair of tubular cooling members 13 having a cross section as shown in FIG. 2.

Each of the cooling members 13 has a plane upper face 13a adapted to be heat conductively connected with the inner face of the top wall 11 and a part-cylindrical lower face 13b constituting a contact face for the fluorescent tubes 14. The cavity 13c of the members 13 is provided for circulating a coolant.

The fluorescent tubes 14 are mounted inside the housing 10 by means of a pair of conventional sockets 15 at either end of the housing. As shown in FIG. 3, the sockets 15 are mounted adjacent the ends of the side walls 12 by means of a hinge-like structure 16,17 actuated by spring elements 18 urging the sockets and hence the fluorescent tubes upwardly, so as to provide for a suitable contact pressure against the contact faces 13b of the cooling members 13.

Obviously, other and equivalent spring means, such as spring coils 18', may be used for pressing the tubes 14 against the contact faces 13b.

In the modified embodiment shown in FIG. 5, both the housing 10 and the cooling members are of trapezoidal cross section and a pair of concave reflector screens 20 are mounted intermediate the cooling members 13 and the lower ends of the side walls 12.

As shown in FIGS. 6 and 7, the ends of the cooling members 13 may be assembled by means of a pair of connecting pipes 21 each provided with a connecting nipple 22 for interconnecting the cooling units according to FIGS. 6 and 7 in a series of interconnected fixtures in a water circuit W, as schematically shown in the diagram of FIG. 8.

The cooling structure shown in FIGS. 6 and 7 provides for a stiff and rugged frame structure which can be manufactured as a separate unit ready for being mounted within the casing 10, and, if convenient, the accessories 19 for the fluorescent tubes 14 may also be combined with this unit, as indicated by the broken lines in FIG. 6.

The conventional accessories 19 for the fluorescent tubes 14 comprising reactor coils and capacitors (where required) are mounted on the inside of the top wall 11 intermediate the two cooling members 13, and the heat emitted from these accessories will, therefore, also to a large extent be absorbed by the cooling system.

Referring finally to the diagram of FIG. 8, this shows schematically a water cooling circuit W including by way of examples three series connected fixtures provided with cooling units C, as shown in FIGS. 6 and 7, interconnected by means of the nipples 22. The circuit W further includes a conventional heat pump and a conventional heat exchanger HE, such as a radiant heating and cooling sub-ceiling comprising a plurality of plate elements connected with a pipe system for circulating heating or cooling water.

When, during the hot season, cooling of the sub-ceiling is required, the cooling water circulated through the pipes of the sub-ceiling may conveniently be circulated through the cooling units C of the lighting fixtures, thereby providing for a simplification of the installation as a whole.

Alternatively, when during the cold season, heating of the sub-ceiling is required, the operation of the heat pump is reversed, and the heat emitted by the fluorescent tubes and recuperated in the water circuit W will considerably contribute to and in some cases even suffice for the heating of the sub-ceiling.

The lighting fixtures according to the invention when interconnected in end-by-end relation, so as to form a continuous channel 10a, may conveniently be combined with a traditional ventilation and air cooling system wherein an air current is circulated through the said channel.

Claims

1. A lighting fixture comprising an elongated, downwardly opening housing substantially rectangular in plan and having a top wall and a pair of side walls, a pair of tubular contact members mounted within the housing heat conductively associated with the top wall thereof and having concave part-cylindrical contact faces, a pair of fluorescent tubes mounted within the housing below the tubular contact members with the upper part of their cylindrical surface contacting the contact face of said tubular contact member, said fluorescent tubes being associated with electrical accessories including reactor coils, said accessories being mounted in the housing on the lower side of the top wall intermediate said tubular contact members, a pair of sockets resiliently mounted at either end of the housing for mounting the fluorescent tubes therebetween, said sockets comprising spring means for urging the fluorescent tubes upwardly against the contact faces of the tubular contact members, and means for

2. A cooling unit for a lighting fixture, as claimed in claim 1, comprising a pair of tubular contact members, a pair of connecting pipes interconnecting said tubular contact members at either end thereof, so as to define a substantially rectangular frame structure and a nipple mounted on said connecting pipes for interconnecting a series of adjacent fixtures, so as to provide a circuit for circulating a coolant through the

3. A lighting fixture comprising an elongated, downwardly opening housing substantially rectangular in plan and having a top wall and a pair of side walls, a contact member defining a concave face mounted to said housing, at least one fluorescent tube mounted in said housing and extending in the lengthwise direction thereof with the cylindrical surface of the tube against the concave face of the contact member, said housing comprising a pair of sockets adjacent the ends thereof for mounting the tube therebetween, said sockets being spring loaded in the direction of the contact member and movable relative to the housing, so as to firmly clamp the cylindrical surface of the tube against the concave face of the contact member.