Emergency lighting system for gaseous discharge lamps

Claim 2

An emergency lighting system comprising: a gaseous-discharge lamp, means for applying electrical energy to said gaseous-discharge lamp to operate said gaseous-discharge lamp, incandescent light means, and switching means, including at least one solid-state voltage-breakdown device, for connecting said incandescent light means to said energy-applying means when said gaseous discharge lamp is extinguished to light said incandescent light means, and for disconnecting said incandescent light means from said energy-applying means after re-striking of said gaseous-discharge lamp, in response to the voltage across the gaseous-discharge lamp approaching a stable voltage.

Claim 3

In combination with a gaseous-discharge lamp having current limiting ballast means connected thereto, an emergency lighting system comprising: means for applying electrical energy to the ballast means and gaseous-discharge lamp sufficient to ignite and operate said gaseous-discharge lamp, incandescent light means, and switching means, including at least one solid-state voltage-breakdown device, for connecting said incandescent light means to said energy-applying means when said gaseous-discharge lamp is extinguished to light said incandescent light means, and for disconnecting said incandescent light means from said energy-applying means after re-striking of said gaseous-discharge lamp, in response to the voltage across the gaseous-discharge lamp approaching a stable voltage.

Claim 4

In combination with a gaseous-discharge lamp having current limiting ballast means connected thereto, an emergency lighting system comprising: means for applying electrical energy to the ballast means and gaseous-discharge lamp sufficient to ignite and operate said gaseous-discharge lamp, incandescent light means, and switching means, including at least one solid-state voltage-breakdown device, for connecting said incandescent light means to said energy-applying means when said gaseous-discharge lamp is extinguished to light said incandescent light means, and for disconnecting said incandescent light means from said energy-applying means after re-striking of said gaseous-discharge lamp, in response to the voltage across the gaseous-discharge lamp approaching a stable voltage.

Claim 5

In combination with a gaseous-discharge lamp having current limiting ballast means connected thereto, a continuous lighting system comprising: means for applying a voltage to the ballast means and gaseous-discharge lamp sufficient to ignite and operate said gaseous-discharge lamp, incandescent light means, second means for applying a voltage to the incandescent light means, solid-state voltage breakdown means responsive to the extinguishment of said gaseous-discharge lamp for rendering effective said second voltage applying means to light said incandescent light means to provide continuous lighting, said voltage breakdown means further responsive to the re-ignition of said gaseous-discharge lamp for rendering ineffective said second voltage applying means to extinguish said incandescent light means.

Claim 6

In combination with a gaseous-discharge lamp having current limiting ballast means connected thereto, a continuous lighting system comprising: means for applying a voltage to the ballast means and gaseous-discharge lamp sufficient to ignite and operate said gaseous-discharge lamp, incandescent light means, second means for applying a voltage to the incandescent light means, solid-state voltage breakdown means responsive to the extinguishment of said gaseous-discharge lamp for rendering effective said second voltage applying means to light said incandescent light means to provide continuous lighting, said voltage breakdown means further responsive to the re-ignition of said gaseous-discharge lamp for rendering ineffective said second voltage applying means to extinguish said incandescent light means.

Claim 7

In combination with a gaseous discharge lamp having a first main electrode and a second main electrode, and current-limiting ballast means connected to at least one of said first and second main electrodes, a continuous lighting system, comprising: incandescent light means; a switch connected to form a series combination with said incandescent light means, said series combination being connected to an emergency voltage supply, trigger means for controlling said switch including voltage breakdown means and connected in parallel across the gaseous-discharge lamp; the main operating voltage establishing a voltage applied to said voltage breakdown means below its threshold level while there is conduction between the first and second main electrodes, cessation of such conduction resulting in voltage being applied to said voltage breakdown means above its threshold level, closedly triggering said switch and igniting said incandescent light means.

Claim 8

In combination with a gaseous discharge lamp having a first main electrode and a second main electrode, and current-limiting ballast means connected to at least one of said first and second main electrodes, a continuous lighting system, comprising: incandescent light means; a switch connected to form a series combination with said incandescent light means, said series combination being connected to an emergency voltage supply, trigger means for controlling said switch including voltage breakdown means and connected in parallel across the gaseous-discharge lamp; the main operating voltage establishing a voltage applied to said voltage breakdown means below its threshold level while there is conduction between the first and second main electrodes, cessation of such conduction resulting in voltage being applied to said voltage breakdown means above its threshold level, closedly triggering said switch and igniting said incandescent light means.

Claim 9

A continuous lighting system as described in claim 4, wherein: said switch is a set of normally open relay contacts, and said trigger means including a two-terminal bi-directional current conducting semi-conductor and the coil of the relay associated with said contacts.

Claim 10

In combination with a gaseous-discharge lamp having current limiting ballast means connected thereto, a continuous lighting system comprising: a main constant-voltage supply connected to the input of said ballast means; an emergency constant voltage supply having a frequency higher than that of said main voltage supply connected to the input of said ballast means operable upon failure of said main voltage supply; incandescent light means; first control means including voltage breakdown means responsive to the failure of the main voltage supply for rendering effective said emergency voltage supply to light said incandescent light means; and second control means responsive to the frequency of said emergency voltage supply for disconnecting said gaseous-discharge lamp from said emergency voltage supply.

Claim 11

In combination with a gaseous-discharge lamp having current limiting ballast means connected thereto, a continuous lighting system comprising: a main constant-voltage supply connected to the input of said ballast means; an emergency constant voltage supply having a frequency higher than that of said main voltage supply connected to the input of said ballast means operable upon failure of said main voltage supply; incandescent light means; first control means including voltage breakdown means responsive to the failure of the main voltage supply for rendering effective said emergency voltage supply to light said incandescent light means; and second control means responsive to the frequency of said emergency voltage supply for disconnecting said gaseous-discharge lamp from said emergency voltage supply.

Claim 12

In combination with a gaseous-discharge lamp having a first main electrode and a second main electrode, and current-limiting ballast means connected to at least one of said first and second main electrodes; a main constant-voltage supply connected to the input of said ballast; and an emergency constant-voltage supply having a frequency higher than that of the main supply connected to the input of the ballast means operable upon failure of said main supply; a continuous lighting system, comprising: voltage breakdown means; incandescent light means connected to form a first series combination with said voltage breakdown means, said first series combination being connected to the output of the ballast means; switch means connected to form a second series combination with the gaseous-discharge lamp, said second series combination being connected to the output of the ballast means; rectifier means connected to the input of the ballast means operable by a voltage at the frequency of the emergency supply and inoperable by a voltage at the frequency of the main supply, said rectifier operation opening said switch means; operating voltage applied across the ballast means and the gaseous-discharge lamp establishing a voltage across said voltage breakdown means below its threshold level while there is conduction between the first and second main electrodes; failure of the main supply operating the emergency supply, thereby opening said switch means, and applying voltage through the ballast means to said voltage breakdown means above its threshold level to ignite said incandescent light means.

Claim 13

In combination with a gaseous-discharge lamp having a first main electrode and a second main electrode, and current-limiting ballast means connected to at least one of said first and second main electrodes; a main constant-voltage supply connected to the input of said ballast; and an emergency constant-voltage supply having a frequency higher than that of the main supply connected to the input of the ballast means operable upon failure of said main supply; a continuous lighting system, comprising: voltage breakdown means; incandescent light means connected to form a first series combination with said voltage breakdown means, said first series combination being connected to the output of the ballast means; switch means connected to form a second series combination with the gaseous-discharge lamp, said second series combination being connected to the output of the ballast means; rectifier means connected to the input of the ballast means operable by a voltage at the frequency of the emergency supply and inoperable by a voltage at the frequency of the main supply, said rectifier operation opening said switch means; operating voltage applied across the ballast means and the gaseous-discharge lamp establishing a voltage across said voltage breakdown means below its threshold level while there is conduction between the first and second main electrodes; failure of the main supply operating the emergency supply, thereby opening said switch means, and applying voltage through the ballast means to said voltage breakdown means above its threshold level to ignite said incandescent light means.

Claim 14

A continuous lighting system as described in claim 7, wherein said rectifier means includes a capacitor for blocking the frequency of the main supply and allowing the frequency of the emergency supply to be passed therethrough.

Claim 15

In combination with a gaseous-discharge lamp having a first main electrode and a second main electrode; current-limiting ballast means connected to at least one of said first and second main electrodes; a main constant-voltage supply connected to the input of said ballast; and an emergency constant-voltage supply having a frequency different from that of the main supply and connected to the input of the ballast means operable upon failure of the main supply; a continuous lighting system, comprising: first switch means connected to form a first series combination with the gaseous-discharge lamp, said first series combination being connected to the output of the ballast means; switch control means for opening said first switch operably connected to the emergency supply and inoperably connected to the main supply; incandescent light means; and voltage breakdown means connected to form a second series combination with said incandescent light means, said second series combination being operably connected to the main supply and the emergency supply; operating voltage from the main supply establishing a voltage to said voltage breakdown means below its threshold level while there is conduction between the first and second main electrodes, momentary failure of the main supply causing cessation of such conduction resulting in voltage from the main supply being applied to said voltage breakdown means above its threshold level to light said incandescent light means, failure of the main supply operating the emergency supply, thereby causing said switch control means to open said first switch means to disconnect said gaseous-discharge lamp from said emergency supply, and resulting in voltage from said emergency supply being applied to said voltage breakdown means above its threshold level to light said incandescent light means.

Claim 16

In combination with a gaseous-discharge lamp having a first main electrode and a second main electrode; current-limiting ballast means connected to at least one of said first and second main electrodes; a main constant-voltage supply connected to the input of said ballast; and an emergency constant-voltage supply having a frequency different from that of the main supply and connected to the input of the ballast means operable upon failure of the main supply; a continuous lighting system, comprising: first switch means connected to form a first series combination with the gaseous-discharge lamp, said first series combination being connected to the output of the ballast means; switch control means for opening said first switch operably connected to the emergency supply and inoperably connected to the main supply; incandescent light means; and voltage breakdown means connected to form a second series combination with said incandescent light means, said second series combination being operably connected to the main supply and the emergency supply; operating voltage from the main supply establishing a voltage to said voltage breakdown means below its threshold level while there is conduction between the first and second main electrodes, momentary failure of the main supply causing cessation of such conduction resulting in voltage from the main supply being applied to said voltage breakdown means above its threshold level to light said incandescent light means, failure of the main supply operating the emergency supply, thereby causing said switch control means to open said first switch means to disconnect said gaseous-discharge lamp from said emergency supply, and resulting in voltage from said emergency supply being applied to said voltage breakdown means above its threshold level to light said incandescent light means.

Claim 17

The emergency lighting system of claim 2, wherein said voltage-breakdown device has a gate, and further comprising switch means connected to said gate of said voltage-breakdown device, for rendering said voltage-breakdown device conductive in response to extinguishment of said gaseous-discharge lamp, thereby energizing said incandescent lamp.

Claim 18

The system of claim 10, wherein said switch means include a second semiconductor voltage-breakdown device.

Claim 19

The system of claim 10, wherein said gated voltage-breakdown device is a silicon controlled rectifier.

Claim 20

The system of claim 12, wherein said gated voltage breakdown device is a silicon controlled rectifier.