RU2077093C1 - Metal halide lamp - Google Patents

Abstract

FIELD: electrical engineering; metal halide lamps of general and special applications. SUBSTANCE: metal halide lamp has envelope made of optically transparent material with electrodes hermetically sealed in envelope filled with inert gases, mercury, alkali metals halides, at least one radiating metal and mercury halides. In designing of lamp the following relationship is observed:

, where I_l - lamp nominal current, A; d_el - electrode diameter, cm; l_el and l_env - internal length of electrode and envelope, cm; mHgX₂ - amount of mercury halides exceeding designed stoichiometric value relative to at least one of radiating metals, mk molle/cm³; K - proportionality factor, equal to 1.0, cm⁴/A mk moll. Used in mercury halides composition exceeding designed stoichiometric value relative to at least one of radiating metals are mercury iodines and bromides, molar ratio of mercury iodides to mercury bromides being chosen within 0.0 and 2.0. EFFECT: enlarged operating capabilities. 3 cl, 1 tbl, 1 dwg

Description

 The invention relates to the electrical industry, in particular, improves metal halide lamps for general and special lighting.

 Known metal halide lamp containing a quartz burner with hermetically sealed electrodes, filled with inert gas, mercury, alkali and rare earth halides (1).

 In the described lamp, the halides of the emitting metals are used directly, which determines the main disadvantage of these lamps is their low life - due to the ingress of water vapor into the burner due to the hygroscopicity of rare earth halides.

 The closest analogue is a metal halide lamp containing a burner of an optically transparent material with hermetically sealed electrodes filled with an inert gas, mercury, alkali metal halides, at least one of the emitting metals and mercury halides (2).

Pure rare earth metals and mercury halides are used as part of the prototype lamp filling. The formation of rare earth halides occurs in the first hours of operation of the lamp according to the following interaction:
2Me + 3HgX ₂ 2MeX ₃ + 3Hg (1)
where: Me is one of the rare earth metals,
X is halogen.

 Mercury halides are low-hygroscopic compounds, which provides the best vacuum hygiene in the manufacturing process of lamps, which in turn increases the service life.

 The disadvantage of the lamp, however, is its low life. This is explained by the fact that the conditions for the optimal passage of the tungsten-halogen cycle of the return of atomized tungsten from the walls of the burner to the electrode are not created in the lamp, especially, as practice shows, in cases of minimum and maximum values of the interelectrode distance. As a result, in some cases, the tungsten-halogen cycle does not ensure the return of all atomized tungsten to the electrode, due to which the burner blackens and overheats. In other cases, the tungsten-halogen cycle takes anomalous forms and tungsten is transferred from the back of the electrode to its working part, which in some cases leads to a dump of the electrode and lamp failure.

 The aim of the invention is to increase the life of the lamp.

где: I_н номинальный ток лампы, А;
d_эл. диаметр электрода, см;
l_эл.вн. внутренняя длина электродов и горелки, см;
l_г.вн. количество галогенидов ртути, превышающих расчетно-стехиометрическое по отношению к по меньшей мере одному из излучающих металлов, мк•моль/см³;
К коэффициент пропорциональности, равный 1,0, имеющий размерность, см⁴/А мк•моль.The goal is achieved in that in a metal halide lamp containing a burner of an optically transparent material with hermetically sealed electrodes, filled with an inert gas, mercury, alkali metal halides, at least one of the emitting metals and mercury halides, the following relation holds for the lamp design:

where: I _{n the} rated current of the lamp, A;
d _email electrode diameter, cm;
l _email internal length of electrodes and burner, cm;
l _onwards the amount of mercury halides in excess of the calculated stoichiometric with respect to at least one of the emitting metals, μ • mol / cm ³ ;
To the coefficient of proportionality equal to 1.0, having a dimension, cm ⁴ / A µ • mol.

 Mercury halides exceeding the calculated stoichiometric ratio with respect to at least one of the emitting metals used mercury iodides and bromides, and the molar ratio of mercury iodides to mercury bromides was selected in the range from 0.0 to 2.0.

The design of the lamp is shown in the drawing. The lamp contains a burner 1 of optically transparent material. The electrodes 2 are hermetically sealed by means of foil inputs 3 and are connected to external current leads 4. The lamp is provided with special sockets 5. The diameter of the electrode d _el. as well as the internal length of the electrodes and burner, l _el.vn. and l _g.vn. .

 The principle of operation of the proposed radiation source is identical to the principle of operation of known metal halide lamps. After connecting the lamp with ballast (inductive, capacitive, inductive-capacitive) resistance, the lamp is ignited by applying a high-voltage electric pulse to the electrodes. An arc discharge arises in an inert gas and mercury vapor medium, with the development of which emitting additives enter the discharge. As a result, an arc discharge is established in the medium of radiating additives with fixed parameters: current, voltage, light flux, etc.

) подбирается по соотношению (2) определенное количество HgX₂, превышающее расчетно-стехиометрическое по отношению к по меньшей мере одному из излучающих металлов. В составе этих галогенидов ртути выбираются йодиды и бромиды ртути, причем отношение (молярное) йодидов ртути к бромидам ртути выбрано в пределах от 0,0 до 2,0. Все это позволяет обеспечить эффективное прохождение вольфрамо-галогенного цикла и увеличить срок службы лампы.The invention consists in the following. The design of the lamp is made in such a way (it was determined experimentally) that depending on the specific current load on the electrode and the "outflow" of the electrodes (it is characterized by the ratio

) a certain amount of HgX _{2 is} selected according to relation (2), which exceeds the calculated stoichiometric ratio with respect to at least one of the emitting metals. Mercury iodides and bromides are selected as part of these mercury halides, and the ratio (molar) of mercury iodides to mercury bromides is selected from 0.0 to 2.0. All this allows for the efficient passage of the tungsten-halogen cycle and increases the lamp life.

 The value of relation (2) is determined experimentally.

 When the ratio exceeds 4,600, the amount of mercury halides exceeding the calculated stoichiometric ratio with respect to at least one of the emitting metals becomes excessive for a particular lamp design and without additional positive effect, lamp ignition is impaired.

 When the ratio value is less than 0.310, the amount of mercury halides exceeding the calculated stoichiometric with respect to at least one of the emitting metals becomes insufficient for the effective passage of the tungsten-halogen cycle and the service life is reduced due to the blackening of the lamp.

 The composition of mercury halides in excess of the calculated stoichiometric with respect to at least one of the emitting metals is also experimentally determined. In lamps with a high specific load on the burner, they should entirely consist of mercury bromides, i.e. the ratio of mercury iodides to mercury bromides is 0.0. Only in this case is it possible to achieve an effective passage of the tungsten-halogen cycle.

 In lamps with a lower burner load, the composition of excess halides should, as shown by experiments, contain both mercury bromides and mercury iodides. Moreover, the ratio of mercury iodides to mercury bromides should not exceed 2.0, otherwise an excessive amount of mercury iodides does not allow creating optimal conditions for the tungsten-halogen cycle to pass, or the purpose of the invention is not achieved.

 As alkali metal halides, cesium and sodium halides can be used. In the latter case, it is necessary to reckon with the intense emission of sodium in the orange region of the spectrum.

 As emitting metals, such metals as dysprosium, helium, thulium, erbium, lutetium are used. These metals, covered by a stable oxide film, are very stable in air. If it is necessary to ensure radiation in the ultraviolet region of the spectrum, iron, nickel, cobalt, tellurium and other emitters are used. Indium, cadmium, scandium and other elements can also be used in the lamp.

 As in most metal halide lamps, argon, xenon, krypton are used as an inert gas in the proposed lamp.

 Examples of specific performance are given in the table.

 The use of the invention will allow for almost constant cost to increase the life of the lamps.

Claims (3)

1. Metal halide lamp containing a burner of an optically transparent material with hermetically sealed electrodes, filled with an inert gas, mercury, alkali metal halides, at least one of the emitting metals and mercury halides, characterized in that the mercury halides are introduced in an amount exceeding calculated - stoichiometric with respect to at least one of the emitting metals, and the lamp parameters are selected so that the following relation is satisfied:

where I _{l is the} rated lamp current, A;
d _el electrode diameter, cm;
l _el.vn , l _gvn internal length of electrodes and burner, cm;
m _Hg X _{2 the} amount of mercury halides in excess of the calculated stoichiometric in relation to at least one of the emitting metals, µmol / cm ³ ;
K = 1 coefficient of proportionality cm ⁴ / A • µmol.  2. The lamp according to claim 1, characterized in that mercury bromides are used as mercury halides.  3. The lamp according to claim 2, characterized in that mercury iodides are additionally introduced into the lamp burner, the molar ratio of mercury iodides to mercury bromides not exceeding 2.

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