DE2009916C2 - Halogen light bulb - Google Patents

Description

hydrogen compounds
14 89441).

The present invention is based on the object To create a Giühlampe as mentioned above, in the case of the inside of the vessel during operation the halogen cycle takes place with the simultaneous presence of fluorine, without the need for special measures which protect the lamp bulb and also the internal components of the lamp against the attack of fluorine protect ropes.

This object is achieved in a lamp of the type mentioned in that the connections are perhalogenated lower hydrocarbons that contain at least one fluorine atom in the molecule.

The perhalogenated lower hydrocarbons are present in an amount which has a concentration of 1 χ 10- »to 1 χ 10-gram atom of fluorine per cm ^{3 of} flask volume and a concentration of 1 χ 10 ^-8 to 1 χ 10-" gram atom of at least one other Halogens per cm ³ flask volume provides, particularly advantageous is a concentration of 7 10 ~ ⁸ to 4 χ 10 ~ ⁷ gram atom fluorine per cm ³ flask volume and a concentration of 7 χ 10 ~ ⁸ to 4 χ 10 ~ ⁷ gram atom of at least one further halogen per cm ^{3 of} piston volume. Perhalogenated methanes of the general composition CFmX ₁ are preferably added to the inert filling gas, where X is chlorine and / or bromine and / or iodine, while m is at least 1, η is at most 3 and the sum of m + η equals 4. Also perhalogenated atanes of the general composition CzFpX ₉ , where X equals chlorine and / or bromine and / or iodine, while ρ equals at least 1, <7 equals at most 5 and the sum of ρ + q equals i am 6 are suitable. Particularly good results are obtained with admixtures of dichlorodifluoromethane (CF2CI2) and of Difluormonochlormonobrommethan (CF ₂ ciBR) and difluorodibromomethane (CF ₂ Br ₂₎ to the filling gas, and also are Trifluormonochlormethan (CF3CI) Trifluormonobrommethan (CF ₃ Br), monofluorotrichloromethane (CFCl 3) , Monofluorotribromomethane (CFBr ₃ ), tetrafluorodibromoethane (C ₂ F ₄ Br ₂ ) and trifluorotrichloroethane (C ₂ F ₃ Cl ₃ ) as well as the corresponding iodine-containing or iodine and chlorine or bromine-containing and also the chlorine and bromine-containing perhalogenated lower hydrocarbons with at least a fluoro aiom in the molecule.

For the purposes of the invention, lower hydrocarbons are hydrocarbons with one to about four carbon atoms in the molecule. The perhalogenated lower hydrocarbons with at least one fluorine atom in the molecule are gaseous at room temperature or already have a very high vapor pressure, the boiling points of CF ₃ CI are at -81.4 ⁰ C, CF ₃ Br at -6O ⁰ C, CF ₃ J at -22 ° C, CF ₂ CI ₂ at -29.8 ° C, CF ₂ ClBr at -4 ° C, CF ₂ Br ₂ at +25 ⁰ C, of CFCl ₃ at +25 ⁰ C and from C ₂ F ₃ Cl ₃ at +47 ⁰ C. The compounds are chemically and thermally very stable. They are also non-toxic. They can be added to the inert lamp filling gas in the required amount without any technological difficulties.

To interpret the operation in the incandescent lamp with an admixture of perhalogenated Hydrocarbons with at least one fluorine atom in the molecule for inert filling gas processes it is assumed that the chemically and thermally stable compounds in the immediate vicinity of the

(DE-OS highly heated luminous element ^{dissociate to a very small extent at above 2000 °} C. and thereby provide a small amount of elemental fluorine in addition to the halogens otherwise present in the molecule. For example, the following reversible disproportionation could occur in the presence of difluorodichloromethane in the lamp bulb :

2 CF ₂ Cl ₂

CF ₄ + CCl ₄

The CF _{4 formed} can then dissociate
2 CF ₄ ^ =? C ₂ F ₆ + 2 F (2)

However, another disproportionation also seems possible:

2 CF ₂ Cl ₂ ^ =; CFCl ₃ + CF ₃ Cl

with the subsequent reactions with the formation of perhalogenated ethanes and elemental halogens

2 CFCl ₃

and

2 CF ₃ Cl
or

2 CF ₃ Cl

C ₂ F ₂ Cl ₄ + 2 Cl
C ₂ F ₄ Cl ₂ + 2 F
C ₂ F ₆ +2 Cl

In addition to the reactions given in equations (1) to (6), other reactions are also conceivable.

which explain the temporary release of elemental fluorine and elemental chlorine from the difluorodichloromethane added to the inert filling gas. Similar considerations also apply to perhalogenated hydrocarbons with a higher or lower chlorine content than in the difluorodichloromethane and with at least one fluorine atom in the molecule; they also apply accordingly to perhalogenated hydrocarbons with bromine atoms and / or iodine atoms and possibly also chlorine atoms and with at least one fluorine atom in the molecule. The exact thermodynamic explanation of the processes inside the bulb during the operation of the lamp is likely to be difficult, but it is not necessary for an understanding of the invention.
The invention thus makes it possible to use the known special advantages of the tungsten-fluorine cycle of regrowth of the evaporated tungsten at the hottest points of the luminous element. In the incandescent lamps according to the invention, therefore, the blackening preventing tungsten-halogen cycle both with the help of fluorine and with the help of another halogen such. B. run off chlorine or bromine. It can be assumed that the tungsten-fluorine cycle only takes place in the immediate vicinity of the luminous element. In any case, the surprising observation, according to which no corrosion of the lamp vessel occurs during operation, points in this direction. The tungsten particles not covered by the fluorine cycle are converted by the second halogen present in the lamp and transported back to the luminous element.

When using perhalogenated hydrocarbons with at least one fluorine atom as an admixture there are also none for the inert filling gas of the lamp

Measures to protect those arranged inside the lamp Components such as B. the brackets for the filament necessary. The regression of the chemically and thermally stable perhalogenated hydrocarbons from the temporary association products is therefore carried out quickly and completely.

In the drawing is a halogen lamp with a Addition of perhalogenated hydrocarbons with at least one fluorine atom in the molecule to the inert Filling gas shown.

The filament made of tungsten (1) is located inside the lamp vessel (2) made of quartz glass and is carried by holding wires (3, 4). The holding wires are connected to the molybdenum foils (5, 6) which are tightly squeezed into the quartz glass and to which the outer pins (7, 8) are welded. The lamp is operated at 24 V with a power consumption of 250 W. The lamp vessel contains a filling of inert gases, such as. B. nitrogen, noble gases or mixtures thereof, and an admixture of perhalogenated lower hydrocarbons with at least one Fiuoratom in the molecule in an amount that a concentration of I χ 10- "to 1 χ 1 0 ~ ^b gram atom fluorine per cm ³ Flask volume and a concentration of 1 χ 10 ~ ⁸ to I χ 10 "gram atom of at least one further halogen per cm ^{3 of} flask volume are set. A concentration of 7 χ IC ^1-8 to 4 χ 10 ⁷ gram atoms of fluorine per cm ^{3 of} bulb volume and of 7 χ 10 " ^s to 4 χ ΙΟ- ⁷ gram atoms of at least one further halogen: per cm ^{3 of} bulb volume is used The cold filling pressure of the lamp can be, for example, 80,000 Pa or more.

The lamp vessel should be dimensioned in such a way that a wall temperature of at least 250 ° C. is reached while the lamp is in operation. It is therefore not necessary to use quartz glass 2: u for the lamp vessel. Other known high-melting glasses, hard glasses or simple glasses can also be used for the lamp vessel. In the drawing, a single-ended Haloger.g'iühlampe is shown. Of course, the invention can also be used with halogen incandescent lamps with other vessel shapes, such as, for. K tubular or spherical bulbs as well as halogen lamps for voltage and power ranges other than those specified in the example can be used.

1 sheet of drawings

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Claims (14)

there is patent claims: 1. Halogen light bulb with Wolfranil lamp and with an addition of halogen-containing compounds to the inert filling gas, which during the Operation of the lamp for the halogen circuit to prevent the lamp bulb from blackening Provide fluorine and at least one further halogen, characterized in that the compounds Perhalogenated lower hydrocarbons are that have at least one fluorine atom in the molecule contain. 2. Halogen incandescent lamp according to claim 1, characterized in that the perhalogenated lower hydrocarbons are present in an amount χ a concentration of 1 10 ^8-1 χ 10 ^-6 gram atom of fluorine per cm ³ of bulb volume and a concentration of 1 χ 10 ~ ^8-1 χ 10 ^-6 gram atom of at least one other halogen per cm ³ of bulb volume provides 3. Halogen incandescent lamp according to claim 1 or 2, characterized in that the perhalogenated lower hydrocarbons are present in an amount which has a concentration of 7 χ 10 ~ ⁸ to 4 χ 10- ⁷ gram atoms of fluorine per cm ^{3 of} bulb volume and a concentration of 7 χ 1O ^-8 to 4 χ 10 ~ ⁷ gram atom at least one further halogen per cm ^{3 of} piston volume provides. 4. Halogen incandescent lamp according to claim 1, 2 or 3, characterized in that perhalogenated methanes of the general composition CFn ₁ X _n are present, where X is chlorine and / or bromine and / or iodine, while m is at least 1, π is at most equal 3 and m + η is 4. 5. Halogen incandescent lamp according to claim 4, characterized in that difluorodicnlormethane (CF2Cl2) is available. 6. Halogen incandescent lamp according to claim 4, characterized in that difluoromonochloromonobromomethane (CF2CIBr) is available. 7. Halogen incandescent lamp according to claim 4, characterized in that Difluordibromrnethan (CFjBrj) is available. 8. Halogen incandescent lamp according to claim 4, characterized in that trifluoromonochloromethane (CF] CI) is present. 9. halogen incandescent lamp according to claim 4, characterized in that trifluoromonobromomethane (CFjBr) is present. 10. Halogen incandescent lamp according to claim 4, characterized in that monofluorotrichloromethane (CFCI3) is present. 11. Halogen incandescent lamp according to claim 4, characterized characterized in that monofluorotribromomethane (CFBr3) is present. 12. Halogen incandescent lamp according to claim 1, 2 or 3, characterized in that perhalogenated ethanes of the general composition C2F _P X <, are present, where X is chlorine and / or bromine and / or | od, while ρ is at least 1, q is at most 5 and ρ + q is 6. 13. Halogen incandescent lamp according to claim 12, characterized characterized in that tetrafluorodibromoethane (C.'FjBrj) is present. 14. Halogen incandescent lamp according to claim 12, characterized characterized in that trifluorotrichloroethane (C2F3CI3) The invention relates to an incandescent halogen lamp with Tungsten incandescent bodies and compounds containing halogens to the inert filling gas, the during operation of the lamp for the halogen circuit to prevent the lamp bulb from blackening Provide fluorine and at least one other halogen. Such a halogen incandescent lamp is z. B. from DE-AS 12 41 531 known. With the help of halogen, for example iodine, bromine, chlorine or fluorine or else a gaseous mixture of these halogens, a cycle takes place inside the lamp during operation from where the evaporated from a tungsten filament and otherwise on the bulb wall deposited tungsten particles at the operating temperature of the lamp vessel to gaseous tungsten halides be implemented and transported back to the light source. Decompose on the hot filament the tungsten halides become free halogens and tungsten, which is deposited on the luminous element. Incandescent lamps with the addition of halogen to the filling gas show none during their entire service life Blackening, its light yield remains almost constant during its operating time. The fluorine cycle has the effect, however, that substance is transported from colder parts of the luminous element to hotter ones until the temperature along the filament is balanced. Since the ends of the filament are from the If power supplies are constantly cooled, they are worn away until they burn through. To this To prevent the incandescent lamp according to DF.-AS 12 41531 no power supply is required and the Luminous body inductively heated by means of a coil through which a high-frequency current flows. Also in the case of an incandescent lamp using fluorine as a halogen additive, in accordance with GB-PS 9 54 729 the return! ansport of the evaporated filament material, e.g. B. of carbon, if a tantalum carbide luminous element Use takes place, preferably at the hottest parts of the luminous element. Through this Deposition of the filament material, the hottest points are also increased in this incandescent lamp, and there is a temperature equalization on the luminous element. In conjunction with a carbide-based lamp are according to GB-PS 9 54 729 already perforated lower hydrocarbons such as CF4 as a filling gas component has been proposed. So far, this advantage of the fluorine cycle could not be evaluated because Particularly cumbersome protective measures were necessary to prevent the fluorine from attacking the vessel material and turn off the internal components of the lamp. Even when using the other halogens, measures are necessary to prevent a possible attack the lamp body ends and the metallic brackets as well as the power supply through the free halogens to prevent or at least to delay. When using bromine this has to be done at the same time Proven presence of hydrogen inside the lamp. The beneficial effects of hydrogen will be through the formation of hydrogen bromide, which causes an attack by the elementary bromine on the metallic components excludes, interpreted. For this purpose, bromine and hydrogen supplying bromine and hydrogen are added to the inert filling gas.