US3769544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purging means and method for xenon arc lamps
Assignee: California Institute of Technology
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Filing: 1972-06-19
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Granted: 1973-10-30
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Expires: 1992-06-19
Abstract
Abstract A high pressure Xenon short-arc lamp with two reservoirs which are selectively connectable to the lamp''s envelope is disclosed. One reservoir contains an absorbent which will absorb both Xenon and contaminant gases such as CO2 and O2. The absorbent temperature is controlled to evacuate the envelope of both the Xenon and the contaminant gases. Thereafter, the temperature of the absorbent is raised to desorb only clean Xenon while retaining the contaminant gases, thereby clearing the envelope of the contaminant gases. The second reservoir contains a gas whose specific purpose it is, by means of steps described in the disclosure, to remove the objectional metal film which deposits gradually on the interior surface of the lamp envelope during normal arc operation. The origin of this film is metal transferred from the cathode of the arc lamp by sputtering or other gas transfer processes. Since the cathodes in different lamps may, for particular purposes, be made of various metals, e.g. Tungsten, Nickel, Rhodium, Molybdenum, it is necessary to use a cleanup gas, and cleanup procedures, that are appropriate to the metal constituting the cathode surface, since it is the cathode surface material, which, transferred to the interior wall of the lamp envelope, constitutes the objectional metal film. Suitable gases and processing methods are described in the disclosure for a variety of cathode metals.
Inventors
- 👤 C Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:09
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/24; H01J61/26; H01J61/84; H01J61/86; H01J61/98
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
64 words
In a high pressure gas discharge arc lamp, as recited in claim 1 wherein said cathode means is of a selected metal, particles of which are depositable on the interior wall of said envelope during operation, thereby reducing the transparency of said envelope, and said arrangement further includes means for reacting with said particles, so as to remove them from said envelope interior wall.
Claim 2
Dependent Claim
76 words
In a high pressure gas discharge arc lamp, as recited in claim 2, wherein said metal particles on wall are tungsten and said means for reacting form a tungsten-containing gas with said tungsten particles when said envelope is heated to at least several hundred degrees centigrade, said envelope further containing a filament means heatable to a glow, for dissociating said tungsten containing gas, whereby said tungsten particles are deposited on, and adhere to said glowing filament.
Claim 3
Dependent Claim
286 words
In a high pressure gas dischargeable arc lamp of the type including a gas-tight envelope for containing a selected gas dischargeable during operation between a metal anode means and a metal cathode means in said envelope, with metal of said cathode becoming separated from said cathode, and depositable as a metal film on the interior surface of said envelope, an arrangement for removing the metal film from the envelope''s interior surface during non-operative periods of said lamp, comprising: first storage means coupled to said envelope to form a gas-tight system therewith, whereby gas is transferable between said envelope and said storage means; a first selected material in said first storage means of a type which reacts in gas form with said metal film above a preselected temperature to form a gas containing said metal, so as to remove said metal film from said envelope surface; temperature control means for controlling the temperature of said first storage means and the first selected material therein, whereby when said temperature is above the first value, said first selected material in a gas form exits said first storage means into said envelope; and when the temperature is below a second value, said first material in gas form in said envelope returns to said first storage means; means for heating said envelope to above said preselected value, whereby said first material in gas form in said envelope reacts with the metal film On the interior surface of said envelope to form a particular gas therewith; means for separating said particular gas, and for adsorbing the metal content therefrom; and first valve means for controlling the flow of said first material in gas form between said envelope and said first storage means.
Claim 4
Dependent Claim
43 words
In a high pressure gas discharge arc lamp, as recited in claim 4, wherein said means for separating comprises a filament, heatable to a temperature range at which said particular gas dissociates into said metal film and said first material in gas form.
Claim 5
Dependent Claim
25 words
In a high pressure gas discharge arc lamp, as described in claim 5, wherein said filament is of the same metal as said metal film.
Claim 6
Dependent Claim
30 words
In a high pressure, gas discharge arc lamp, as described in claim 6, wherein said cathode and said filament are of tungsten, and said filament is heatable to a glow.
Claim 7
Dependent Claim
23 words
In a high pressure, gas discharge arc lamp, as recited in claim 7, wherein said first material is a halogen or halogen-containing compound.
Claim 8
Independent Claim
131 words
A method of removing metal film from the interior surface of the envelope of a high pressure gas dischargeable arc lamp during non-operation of said lamp which is of the type including a gas-tight envelope which contains a selected gas dischargeable during operation between a metal anode and a metal cathode, said film comprising particles of said cathode which are removed therefrom during maintenance periods of lamp non-operation, the steps comprising: reducing the pressure in said envelope from said dischargeable gas to a preselected value; introducing into said envelope a preselected gas which at a selected temperature range reacts with said metal film to form a metal-containing gas by heating said envelope to said selected temperature range; and removing from said envelope the preselected gas together with the newly-formed metal-containing gas.
Claim 9
Dependent Claim
25 words
A method as described in claim 9 further including the step of dissociating said metal-containing gas prior to removing said preselected gas from said envelope.
Claim 10
Dependent Claim
48 words
A method as described in claim 10 wherein said envelope includes a heatable filament adjacent said cathode and said metal-containing gas is dissociated by heating said filament to a glow, whereby the metal in said metal-containing gas is dissociated from said preselected gas and adheres to said filament.
Claim 11
Independent Claim
173 words
A method of removing from the envelope of a high pressure gas dischargeable arc lamp during non-operation periods gas contaminants which are formed during lamp operation the steps comprising: providing in storage means an adsorbent material capable of adsorbing and desorbing said dischargeable gas and said gas contaminants as a function of the temperature thereof; providing a gas-tight connection between said envelope and said storage means including a valve for controlling the flow of gases between said storage means and said envelope; controlling the temperature of said adsorbent material to adsorb said dischargeable gas and said gas contaminants to thereby reduce the pressure in said envelope to a first preselected value; controlling the temperature of said adsorbent material by raising it above the desorption temperature of said dischargeable gas to cause said adsorbent material to desorb only said dischargeable gas while adsorbing said gas contaminants, until the pressure in said envelope reaches a second preselected non-operating pressure; and inhibiting by means of said valve gas flow between said envelope and said storage means.
Claim 12
Dependent Claim
39 words
A method as described in claim 12 wherein said envelope is first evacuated of substantially all of said dischargeable gas and said gas contaminants before said dischargeable gas is desorbed from said adsorbent material by controlling the latter''s temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |