Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01K—ELECTRIC INCANDESCENT LAMPS
  • H01K1/00—Details
  • H01K1/02—Incandescent bodies
  • H01K1/04—Incandescent bodies characterised by the material thereof
  • H01K1/10—Bodies of metal or carbon combined with other substance
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01K—ELECTRIC INCANDESCENT LAMPS
  • H01K1/00—Details
  • H01K1/50—Selection of substances for gas fillings; Specified pressure thereof

Definitions

• Light source and a method for providing a transport function for a chemical element in a light source
• the invention relates to a light source with a heatable filament, wherein the filament is arranged in a piston and wherein a gas or a gas mixture is arranged in the piston, which or to provide a transport function for at least one chemical element emitted by the filament back on and / or is suitable in the filament. Furthermore, the invention relates to a method for providing a transport function for a chemical element in a light source with a heatable filament, wherein the filament is arranged in a piston and wherein a gas or a gas mixture is arranged in the piston, which is used to provide the Transport function for at least one chemical element released by the filament is suitable back on and / or into the filament.
• an incandescent lamp which has an incandescent filament made of a high-melting or refractory material, electrodes which hold the filament as webs, and a bulb which is filled with a gas mixture.
• Incandescent lamps currently have the lowest energy efficiency within the available lamp technologies. That means they generate a lot of heat compared to light emission. On the other hand, however, they are the least expensive lamps or light sources to manufacture. It is therefore desirable to increase the energy efficiency of incandescent lamps. This can be achieved by using high-melting or refractory carbides, borides, nitrides, oxides or suicides as filament material. for example tantalum hafnium. Among these materials are the carbides, in particular special hafnium carbide and tantalum carbide, because of their high melting point, their good electrical conductivity and their great thermal mechanical stability.
• tantalum carbide as a representative of the metal carbide when used for incandescent lamps, has a much higher applicable annealing temperature and, in addition, a higher selectivity or yield of light emission in the visible range than the tungsten usually used for incandescent lamps.
• Incandescent lamps with tantalum carbide filaments can achieve significantly higher energy efficiencies than tungsten incandescent lamps.
• tantalum carbide as a filament material at high temperatures is its tendency to give off carbon and thereby convert it into less temperature-stable tantalum carbide phases or even into metallic tantalum.
• Incandescent lamps with a filament made of refractory materials such as metal carbides, metal borides, metal silicides and the like are known from German patent application N 2038 Vlllc / 21f dated July 26, 1961 and from US patent applications 14253 and 14254 dated March 11, 1960. From these patent applications, a mass transfer cycle within the lamps is also known, which works by means of halogen compounds. Evaporating filament material such as carbon, boron or silicon can be returned to the filament using the mass transfer cycle.
• the known mass transfer cycles must either take place in a completely oxygen-free or in a completely hydrogen-free atmosphere in order to achieve a suitable effectiveness.
• the present invention is therefore based on the object of specifying a light source and a method for providing a transport function of the type mentioned at the outset, according to which high energy efficiency is achieved with simple means.
• the above object is achieved by a light source with the features of claim 1.
• the light source is designed and developed in such a way that the gas or the gas mixture has an enrichment of oxygen and / or of an oxygen-containing compound.
• halogen compounds are not inevitably required to generate a transport cycle or a transport function within a bulb of a light source.
• an enrichment of the gas present in a flask or of the gas mixture present there from oxygen and / or from an oxygen-containing compound likewise provides a suitable transport cycle or a suitable transport function for returning chemical elements released from the filament can.
• the oxygen is preferably not added in the form of molecular oxygen, but in the form of an oxygen-containing inorganic compound such as NO 2 , N 2 O, CO, CO 2 , or an oxygen-containing organic compound - for example alcohol, aldehyde, ketone, carboxylic acid.
• the amount of substance of the element oxygen per volume unit correlating with the number of oxygen atoms per volume unit is preferably at least 1 * 10 "5 mol / l and is particularly preferably at most 1 * 10 " 4 mol / l.
• a quantity of substance between 8 * 10 "7 mol and 8 * 10 " 6 mol at 70 ml is typical.
• the light source according to the invention specifies a light source in which high energy efficiency is achieved with simple and therefore inexpensive means.
• the flask further contains a low molecular weight hydrocarbon.
• the low molecular weight, saturated or unsaturated hydrocarbon preferably contains no more than 4 carbon atoms, because otherwise the vapor pressure is no longer sufficiently high.
• the partial pressure of the hydrocarbon introduced is preferably at least 0.1 mbar and is particularly preferably at most 1.5 mbar.
• the light source according to the invention specifies a light source in which a mass transport cycle or a transport function can be achieved, according to which evaporating or released filament material such as carbon, boron or silicon can be returned to and / or into the filament.
• a mass transport cycle or a transport function can be achieved, according to which evaporating or released filament material such as carbon, boron or silicon can be returned to and / or into the filament.
• the filament can essentially consist of a metal carbide, preferably of tantalum carbide.
• a transport function can be generated in a particularly safe manner by enrichment or targeted addition of carbon monoxide as an oxygen-containing compound.
• the low molecular weight hydrocarbon can comprise C 2 H 2 .
• C 2 H 2 can also return carbon evaporated from the filament to the filament, for example.
• carbon monoxide and C 2 H 2 can simultaneously serve as generators for a transport function.
• the low molecular weight hydrocarbon can comprise methane or ethane.
• the gas or the gas mixture in the flask can be enriched with hydrogen.
• the partial pressure of hydrogen (H 2 ) is preferably at least 10 mbar and is particularly preferably at most 100 mbar.
• suitable gases or gas mixtures into the flask, which are then directly suitable for providing a transport function for a chemical element.
• chemical elements or compounds can also be introduced into the bulb, which only react during light source operation in such a way that the desired atmospheric composition is created in the bulb.
• the enrichment or the enrichments can be formed by reaction of suitable chemical elements or compounds in the bulb during the operation of the light source or the heating of the filament.
• low-molecular hydrocarbons can be introduced into the flask together with at least one - preferably volatile - oxygen-containing carbon compound or oxygen-containing, gaseous compound and hydrogen in suitable ratios to one another.
• at least one - preferably volatile - oxygen-containing carbon compound or oxygen-containing, gaseous compound and hydrogen in suitable ratios to one another.
• the particular application - for example the design, the desired service life and the desired performance values - must be used.
• the total number of hydrogen, oxygen or carbon atoms in the lamp, ie based on all the compounds introduced into the lamp, is preferably in each case in defined ranges.
• the correlating amounts of substance of the oxygen element introduced into the gas atmosphere are preferably in the range between 1 * 10 "6 mol / l and 1 * 10 " 5 mol / l, the carbon element introduced preferably between 4 * 10 "6 mol / l and 4 * 10 " 5 mol / l and the hydrogen element introduced preferably between 8 * 10 "4 mol / l and 2 * 10 " 2 mol / l.
• the at least one oxygen-containing carbon compound can have an alcohol, an aldehyde, a ketone, a monocarboxylic acid or a dicarboxylic acid.
• the at least one oxygen-containing compound can have CO 2 , NO, NO 2 or N 2 O.
• an excess of hydrogen compared to free oxygen can be formed in the flask.
• the ratio of the number of atoms per unit volume proportional concentrations of the elements hydrogen and oxygen per unit volume should preferably be greater than 10: 1 and particularly preferably not greater than 100: 1.
• the enrichment of oxygen can be at least 50 ppm within the atmosphere surrounding the filament.
• the above object is further achieved by a method for providing a transport function for a chemical element in a light source with the features of claim 13.
• the method mentioned at the outset is designed in such a way that the gas or the gas mixture is enriched with oxygen and / or an oxygen-containing compound and possibly also with a low molecular weight hydrocarbon.
• the invention enables one or more halogen-free mass transfer cycles for, for example, carbon.
• One of the mass transfer cycles according to the invention can be based on oxygen-containing compounds and / or on oxygen and possibly additionally on a low molecular weight hydrocarbon.
• the filament within the bulb can be supplied with carbon, for example, whereby the service life of the light source can be increased.
• At least one chemical transport cycle that does not use halogen compounds can be provided, or at least one further chemical transport cycle without halogen compounds can be superimposed on a chemical transport cycle based on halogen compounds.
• the invention can be used with all light sources or incandescent lamps with refractory or refractory filament materials, as described, for example, in the "Handbook of Chemistry and Physics", CRC-Press-Verlag, 80th edition, Tables of refractory materials, Chapter 12, page 207- 208 and Tables of physical constants of inorganic compounds, Chapter 4, page 37 ff.
• a particularly suitable embodiment is formed by a light source with a tantalum carbide filament.
• the procedure for generating a halogen-free carbon transport cycle in the flask is as follows.
• hydrogen and carbon monoxide can also be introduced into the flask. This can be done in several ways.
• such a gas mixture can be synthesized from the desired gases and introduced into the flask.
• other suitable chemical compounds can be introduced into the bulb, which react in light source operation in such a way that the desired atmospheric composition is created.
• low molecular weight hydrocarbons together with one or more volatile, oxygen-containing carbon compounds for example water, alcohols, aldehydes, ketones, monocarboxylic acids, dicarboxylic acids and the like, or with one or more oxygen-containing, gaseous compounds, for example CO 2 , NO, NO 2 , N 2 O or other “nitrous oxide derivatives” and the like, and hydrogen is introduced into the lamp bulb in certain ratios to one another.
• other low-molecular hydrocarbons, cyanides, NH 4 , CO 2 , H 2 can then be found O, N 2 but mainly form CO.
• methane was introduced into the flask together with hydrogen and acetone and an inert gas in a certain mixing ratio or with certain partial pressures.
• the use of noble gases is irrelevant to the understanding of the invention and is therefore not discussed further.
• H 2 O, C 2 H 2 small amounts of CO 2 and especially CO were then formed during lamp operation. As the operating time increases, methane is broken down more and more and CO is built up more and more. Due to the formation of CO, the oxygen binds free carbon and thus suppresses lamp lamp sooting.
• the reaction sales via reaction channels with CO 2 are irrelevant because of the small amount of CO 2 .
• the existing dissociated elemental hydrogen mainly reacts with free carbon to methane and C 2 H 2 . This can be concluded from the heavy lamp bulb sooting that occurs when the hydrogen is no longer in excess of the free carbon.
• the CO as well as the C 2 H 2 with 1076.5 kJ / mol and 962 kJ / mol has a high and even about twice as high dissociation energy as all other possible thermal dissociation fragments of the atmospheric components mentioned, it can only in the hottest area of the lamp - Dissociate on hot tantalum carbide filament, for example - and release the carbon to the filament.
• the released oxygen then primarily reacts with the free carbon that is evaporated from the filament to form CO, and this can transport the carbon back to the filament. This creates a CO cycle.
• the reaction of the free oxygen with the tantalum of the filament does not take place in the strongly reducing hydrogen atmosphere or because of the large excess of hydrogen set.
• C 2 H 2 can also transport the carbon evaporated from the filament back to the filament.
• the C 2 H 2 completely dissociates into carbon and hydrogen.
• the free hydrogen can then recombine with the free carbon evaporated from the filament to form CH, which can then react further to methane or again to C 2 H 2 .
• the latter can then transport the carbon back to the filament. Since the methane primarily releases hydrogen during its thermal dissociation, its CH dissociation fragments can also form the C 2 H 2 .
• the carbon transport through the C 2 H 2 dissociation therefore takes place together with the methane dissociation. As a result, a C 2 H 2 / CH 4 cycle is formed.
• Fig. In a schematic side view of an embodiment of a light source according to the invention.
• FIG. Shows a schematic side view of an embodiment of a light source according to the invention.
• the light source has a heatable filament 1, the filament 1 being arranged in a bulb 2.
• the filament 1 is heated via electrical contacts 3 and 4.
• a gas or a gas mixture is arranged in the piston 2, which, in order to provide a transport function for at least one chemical element emitted by the filament 1, returns to and / or in the filament 1 is suitable.
• the gas or the gas mixture is enriched with oxygen and / or with an oxygen-containing compound.
• the oxygen is preferably not added in the form of molecular oxygen, but in the form of an oxygen-containing inorganic compound such as NO 2 , N 2 O, CO, CO 2 , or an oxygen-containing organic compound - for example alcohol, aldehyde, ketone, carboxylic acid.
• an oxygen-containing inorganic compound such as NO 2 , N 2 O, CO, CO 2 , or an oxygen-containing organic compound - for example alcohol, aldehyde, ketone, carboxylic acid.
• the amount of substance of the element oxygen per volume unit correlating with the number of oxygen atoms per unit volume is preferably at least 1 * 10 '5 mol / l and is particularly preferably at most 1 * 10 "4 mol / l.
• a quantity of substance between 8 * 10 " is typical. 7 mol and 8 * 10 "6 mol at 70 ml.
• Filament 1 consists essentially of tantalum carbide.
• the oxygen-containing compound has carbon monoxide.
• the lamp bulb made of soft glass has a volume of 70 ml.
• the filament made of tantalum carbide is attached to power supply lines made of molybdenum.
• the filament temperature is 3600 K, the average bulb temperature is approx. 400 ° C.
• the composition of the gas phase for this lamp is as follows:
• the lamp bulb made of quartz glass has a volume of 0.5 ml.
• the filament consists of tantalum carbide, the outlets in the lower part of tantalum.
• the lamp is operated at 3600 K, the average bulb temperature is 500 ° C.
• the composition of the gas phase for this lamp is as follows:

Landscapes

• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Luminescent Compositions (AREA)
• Discharge Lamp (AREA)
• Resistance Heating (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2004
  • 2004-04-27 TW TW093111668A patent/TWI270918B/zh not_active IP Right Cessation
  • 2004-05-19 EP EP04738536A patent/EP1627418A1/de not_active Withdrawn
  • 2004-05-19 CA CA002527209A patent/CA2527209A1/en not_active Abandoned
  • 2004-05-19 KR KR1020057022577A patent/KR20060017817A/ko not_active Application Discontinuation
  • 2004-05-19 WO PCT/DE2004/001066 patent/WO2004107391A1/de not_active Application Discontinuation
  • 2004-05-19 JP JP2006529605A patent/JP2007501505A/ja active Pending
• 2005
  • 2005-11-28 US US11/287,985 patent/US20060091800A1/en not_active Abandoned

Non-Patent Citations (1)

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