Electric lamp and discharge devices: systems – Automatic substitution of the load device or electrode – Plural substitution of load devices or electrodes
Reexamination Certificate
2000-05-22
2001-08-07
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Automatic substitution of the load device or electrode
Plural substitution of load devices or electrodes
C315S061000, C315S289000, C362S235000, C362S439000
Reexamination Certificate
active
06271630
ABSTRACT:
BACKGROUND OF THE INVENTION
High intensity discharge lamps are typically used in applications where the lamp is spaced a substantial distance from the surface to be lighted, such as, a sports arena, a traffic highway interchange, a warehouse, shopping malls, atriums, or other similar applications. When the discharge lamp burns out through usage, it can be expensive and bothersome to replace the lamp. It is particularly desirable to reduce the number of times that it is necessary to re-lamp a particular fixture and avoid resulting interruptions. It is also desirable to provide a construction wherein the life of an operating fixture is extended to reduce the frequency of re-lamping the fixture.
High intensity discharge lamps are energized by an electric current to create a metallic vapor and the current through the lamp causes high intensity illumination. Lamps of this type do not illuminate instantaneously, but require time for the lamp to ignite. When a high intensity discharge lamp is fully operational and the current to the lamp is interrupted for a short period of time, the lamp will not reignite immediately. The lamp must cool down before it will reignite. The period of cooling varies from lamp to lamp. The cooling may be as short as a few minutes, or as long as twenty minutes. In certain instances the period of non-ignition of high intensity discharge lamps may be dangerous, such as, in a sports arena. A crowd of spectators could panic because of the darkness of the arena. Various systems are used to solve the problem, such as, providing an emergency lighting system in a sports arena, those systems typically providing enough light to allow sports fans to leave the arena.
It is desirable to provide a high intensity discharge lighting system in which the time between re-lamping is extended, as well as provision for instant or reduced restrike time for lamps that experience a momentary power interruption. Interruption of electric current to a first high intensity discharge lamp and re-establishment of the current ignites another high intensity discharge lamp to provide lighting in the same area as where the first lamp provided lighting.
SUMMARY OF THE INVENTION
The present invention relates to an improved high intensity discharge lighting fixture, which includes two high intensity discharge sockets. A high intensity discharge lamp is mounted in each of the sockets. Each of the sockets with its respective lamp is electrically connected in parallel to a ballast which is in turn connected to a source of electric power. The ballast provides starting voltage in parallel to both sockets. When the first lamp is struck, it begins warm-up and no current flows through the second lamp, which now has no starting voltage at its socket. The effective maintenance of the lamps is greatly reduced in view of the fact that one lamp will be operative for a period. When the lamps are restruck, the other lamp may be operative instead. Thus, there is a life balance between the two lamps and a significant increase in the life of the operative fixture. The lamps experience normal maintenance are exchanged for new lamps when both reach end-of-life, but the time for re-lamping the fixture is extended.
Should the electric current to the ballast be interrupted, the ignited lamp would cease to produce illumination. However, when the electric current is re-established to the ballast, and the first lamp which was previously ignited has not cooled sufficiently to be restruck, the current from the ballast flows through the second lamp (now ignited) and no current flows through the first lamp. The arrangement allows illumination to be produced from the fixture even if there is a short-term interruption of electric current to the fixture.
REFERENCES:
patent: Re. 36414 (1999-11-01), Tickner
patent: 3693045 (1972-09-01), Price
patent: 3949211 (1976-04-01), Elms
patent: 6095662 (2000-08-01), Burroughs et al.
Indy Lighting, Inc.
Philogene Haissa
Zummer Anthony S.
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