Patent Application
20070109795
The present invention pertains to the field of lighting assemblies, and particularly, to lighting assemblies with systems for dissipation of heat from ballasts.
Fluorescent lamps are becoming increasingly popular in both commercial and residential applications. Fluorescent lamps are more energy efficient and last longer than traditional incandescent lights. In use, the visible light from a fluorescent lamp is produced by a mixture of phosphors inside the lamp. They give off light when exposed to ultraviolet radiation released by mercury atoms as they are bombarded by electrons. The flow of electrons is produced by an arc between two electrodes at the ends of the lamp.
It is well known that the ambient temperature around a fluorescent lamp can have a significant effect on light output and lamp efficiency. At high temperatures, an excess of mercury vapor is present, absorbing the UV radiation before it can reach the phosphors. Therefore, light output drops. Further, high ambient temperatures may be produced around enclosed fluorescent lamps in interior lighting applications. In all lighting applications however, the ballasts will introduce a substantial amount of heat into the fixtures. The IES Lighting Handbook points out that a 1% loss in light output (for fluorescent lamps in general) can be expected for every 2° F. (1.1° C.) above the optimum ambient temperature. Efficiency can also drop, to some degree, at these higher temperatures. It is, therefore, desirable to try to dissipate as much heat from the system as possible.
The present invention is a thermal dissipation system for a ballast of a lighting system. The thermal dissipation system comprises a ballast housing that is adapted for engagement with an elongate support of a lighting system. The ballast housing comprises a thermally conductive material and is adapted to substantially house a ballast therein. The ballast housing has a body and thermal transfer surfaces that are shaped to substantially conform to portions of the inner surface of the support. In one aspect, the thermal transfer surfaces of the ballast housing are integral with the body of the housing. In another aspect, the ballast is housed within a portion of the body.
The purpose of forming the thermal transfer surfaces to conform to portions of the inner surface of the support is to provide a large surface area for conducting heat from the ballast to the support, for eventual dissipation to the ambient surroundings. In one aspect of the invention, the more surface area of the ballast housing that is in contact with the inner surface of the support, the better and/or more efficient the thermal dissipation provided by the system of the present invention.
These and other features of the preferred embodiments of the present invention will become more apparent in the detailed description, in which reference is made to the appended drawings wherein:
The present invention is more particularly described in the following exemplary embodiments that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. As used herein, “a,” “an,” or “the” can mean one or more, depending upon the context in which it is used. The preferred embodiments are now described with reference to the figures, in which like reference characters indicate like parts throughout the several views.
Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, an alternate embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.
In one aspect, the present invention provides a thermal dissipation system 10 for a ballast 2 of a lighting system. The thermal dissipation system 10 comprises a ballast housing 100 that is adapted for engagement with an elongate support 200 of a common lighting system. In one aspect, the support 200 may be, in some instances, what is typically referred to in the lighting industry as a ballast channel and the ballast housing may be positioned within the channel. However, it will be appreciated that a number of supports of varying shapes and sizes are contemplated.
The ballast housing 100 comprises a thermally conductive material and is made to substantially house the ballast 2 therein. The thermally conductive material may be, for example and without limitation, aluminum, steel, copper, and the like. The ballast housing 100 has a body 110 and thermal transfer surfaces 120 that are shaped to substantially conform to portions of the inner surface 210 of the support. In one aspect, as illustrated in
In one aspect, the purpose of conforming at least portions of the thermal transfer surfaces 120 to complementary portions of the inner surface 210 of the support 200 is to increase or maximize the amount of conjoined, thermally conductive surface area between the elongate support and the thermally conductive ballast housing. This, in turn, increases or maximizes the ability of the system 10 of the present invention to conduct heat from the ballast to the support, for eventual dissipation to the ambient surroundings. Thus, the more surface area of the ballast housing that is in contact with the inner surface of the support, the better or more efficient the thermal dissipation of the system.
In one example, at least 40% of the thermal transfer surfaces 120 of the ballast housing 100 substantially contact portions of the inner surface of the support 200. In another example, at least 80% of the thermal transfer surfaces of the ballast housing substantially contact portions of the inner surface of the support 200.
As mentioned above, it is desirable to have as much surface area in contact between the support and the thermal transfer surfaces of the ballast housing 100. As can be appreciated, when the ballast housing is mounted thereon the support, portions of the support may have a tendency to bend and move away from the housing. To counter this effect, in one aspect of the invention, the support comprises a pair of opposing surfaces 220. Where the support is a ballast channel, the opposing surfaces 220 may be the sides of the channel. In this aspect, at least one of the sides of the channel is movable from a first unengaged position in which the support 200 is not engaged with the ballast housing 100 to a second engaged position. In one aspect and referring to
Similarly, in an alternative aspect and referring now to
In another aspect of the invention, the housing defines a trough 130 sized and shaped to accept the ballast 2 therein. The trough 130 and the thermal transfer surfaces 120 may be, for example, formed from a single sheet of material. However, as one skilled in the art can appreciate, the trough may be formed in many various ways. In one aspect, as illustrated in
In another aspect and as illustrated in
Since the ballast is housed within the trough 130 of the ballast housing 100, it may be desirable to further have an endcap 150 thereon one or both ends of the trough of the ballast housing, substantially enclosing the respective end of the trough. In order to facilitate electrical wiring 4, in one aspect, the endcap 150 defines at least one bore 160 therethrough, sized to enable at least one electrical conductor to pass from an interior portion of the trough of the ballast housing through the bore 160.
Although several embodiments of the invention have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the invention will come to mind to which the invention pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the invention is not limited to the specific embodiments disclosed herein above, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described invention, nor the claims which follow.
