EP2197021A1 - Electricity supply element for an electrode and electrode assembly with at least one such electricity supply element - Google Patents

Abstract

The supply element (2) has elongated parts provided with a set of sections (8), which exhibits amalgam-formation material i.e. copper, at an outer side. The sections are connected with an electrode (4) and are in the form of elongated rods, which are bent for holding the rods. Another set of sections (9) consists of a material i.e. nickel, which suppresses amalgam formation. A material core consisting of iron and nickel is surrounded by a layer of amalgam-formation material. The former set of sections is shorter than the latter set of sections.

Description

Technical area

The invention relates to a power supply element for an electrode, which is elongated. Furthermore, the invention also relates to an electrode frame with such power supply elements, wherein the electrode frame is designed for a discharge lamp.

State of the art

From the DE 44 45 532 A1 is a low-pressure discharge lamp with a arranged within the discharge vessel auxiliary or starting amalgam known. The starting amalgam is located on a, preferably designed as a metal sheet or metal grid, coated with an amalgam former carrier body which is partially melted in the glass bead of the electrode frame or in the Teilrohreinschmelzung. Under a Amalgambildner is a material to understand, which is designed for amalgam formation in particular during operation of the discharge lamp. The starting amalgam is preferably designed so that its Hg vapor pressure at room temperature is lower than that of the working amalgam. The location of the starting amalgam is preferably chosen so that its temperature during lamp operation is so high that the work amalgam located at a cooler location regulates the Hg vapor pressure.

The electrode frame includes two power supply elements, which at one end for holding or carrying a E-lektrodenwendel are formed and in this connection are connected to the electrode by terminals. Spaced apart, the two power supply elements are connected or fused with the glass bead, said components representing the electrode frame. The mercury introduced as a filling component into the low-pressure discharge lamp forms indium amalgam with the indium on the metal sheet, which accelerates the start-up of the lamp and is therefore designated as auxiliary or starting amalgam. In addition to indium, other metals such as cadmium are also suitable as amalgam formers. In the known embodiment, an amalgam-forming material acting as starting amalgam is applied only on this additional sheet-metal sheet joined only to the glass bead.

In addition, embodiments are known in which a starter amalgam welded to a power supply element indium-coated stainless steel flag is used. Also, this flag is an additional part which is attached to such a wire-shaped or rod-shaped power supply element.

A major disadvantage of the known embodiments is that an additional part in the form of the metal sheet or the stainless steel flag is required, which in addition must first be attached to the power supply lines in a separate operation. In addition, an additional pre-product is required, which is relatively expensive due to its required galvanic coating. The additional attachment of this flag to a power supply is usually by welding, creating another step is required. Moreover, when melting the power supply elements in the glass bead, it is necessary to work extremely precisely that the power supply element does not oxidize in the region of the weld, which is usually located between the bead and the electrode clamp. To optimize the luminous flux, the flag should get hot as soon as possible. The preferred location of attachment is therefore as close as possible to the electrode or lamp filament. Since in the known manufacturing process, the helix must be pasted after welding the flags with an emitter paste, in this case a required minimum distance to the helix of about 4 mm is required. In addition, the mercury is released in the known embodiments in lamp operation and the indium liquid. Due to the good wetting properties of indium, this tends to creep in the direction of the hot coil. Therefore, losses of the indium can be expected. Experience has shown that a minimum amount of indium of about 2 mg is required for a service life of 10,000 hours. Due to the relatively large amount of indium, significantly more mercury is bound to the flag than is required to operate the lamp (<0.02 mg per 100 ml lamp volume). Depending on this timeout, a few tenths of a mg of mercury from working amalgam are bound to the flag. Since almost all the mercury is expelled from the flags during the starting phase, the lamp is supersaturated with mercury in the start-up phase.

Excess mercury accumulates at a virtual and much too hot cold spot, which is not present in such lamps, however, since they are amalgam lamps is. This much too hot virtual cold spot regulates the mercury vapor pressure until the mercury is completely absorbed by the working amalgam. This process can take up to an hour, whereby the luminous flux can be partially up to 50% below its stabilized value because the lamp is "thermally overrun" in this phase.

Presentation of the invention

It is an object of the present invention to provide a power supply element and an electrode frame, which can be formed on the one hand reduced component and beyond an improved functioning in terms of Hg release and recording excess Hg ensured by the work amalgam in the operation of a lamp.

This object is achieved by a power supply element having the features of claim 1 and an electrode frame having the features of claim 15.

An inventive power supply element for an electrode is formed as an elongate element. An elongated part of the power supply element has a first portion which has an amalgam-forming material on the outside. This configuration ensures that the amalgam-forming material component is virtually integrated in a power supply element, and no separate flag, such as an additional coated metal sheet, more is required. In addition, by this embodiment, a substantially location-targeted attachment of the amalgam-forming material with respect to the positioning of the electrode can be achieved. In particular, the Hg release and the absorption of excess Hg by the work amalgam even during operation of the lamp can be done effectively and efficiently, whereby the operation of the lamp, in particular the starting behavior and the time to stabilization, can be improved.

Preferably, the first portion of the elongated portion of the power supply element is for connection to the electrode. The power supply element is thus designed so that just where the connection to the electrode is provided, the elongate part is formed on the outside with an amalgam-forming material. It is thus provided directly at the junction between the power supply element and the electrode of this amalgam-forming material, so that preferably also at the direct contact point between the electrode and the power supply element, the amalgam-forming material is present. This site-specific attachment allows the amalgam former to be as close as possible to the electrode. The amalgam is therefore very hot and the startup behavior improved significantly. In particular, in lamps with a so-called high temperature amalgam is given a significant improvement with this configuration.

Preferably, it is provided that the elongated part of the power supply element has the first portion, which has an amalgam-forming material on the outside, and a second portion, which on the outside a amalgam formation suppressing material having. The power supply element is thus configured in its elongated part at least in two parts, which thus partially guarantees different functionalities. Especially in the second section, in which a material which suppresses amalgam formation is provided on the outside, amalgam formation can thus be substantially prevented.

Preferably, it can be provided that the first and the second section are separate parts which are connected to one another, for example welded together. Thus, the second part may be a dilatron wire which is butt welded to an amalgam-forming first portion

Especially with amalgam lamps, which have a low mercury vapor pressure in the off state, however, can also be dispensed with this second portion of the power supply element. In electrode frames with a glass bead, however, this second section is provided.

Preferably, the two portions of the elongate part of the power supply element are formed directly adjacent to each other.

In particular, the first section, in which an amalgam-forming material is formed on the outside, is designed to clamp the electrode. In particular, it is provided in this regard that the first section is not completely rectilinear but is bent over. In a specific embodiment, therefore, this first section is formed as an elongated, rod-shaped portion which is bent over.

Preferably, the amalgam-forming suppressing material in the second portion of the elongated portion of the current-carrying element comprises nickel. Such a nickel layer protects the power supply element in the colder region in a particularly efficient manner from amalgamation.

In the second section, the material inhibiting the formation of amalgam is preferably formed with a layer thickness <20 μm, in particular between 1 μm and 5 μm. In particular, therefore, this layer thickness can be made extremely thin, and yet the required functionality can be ensured.

Preferably, the power supply element is formed with a material core surrounded by a layer comprising an amalgam-forming material. In particular, it can be provided that this layer surrounding the material core is formed completely from an amalgam-forming material. In addition, it is particularly provided that the power supply element further comprises a layer which surrounds the core material and the layer comprising the amalgam-forming material. By means of this multilayer structure of the power supply element, a particularly advantageous production can be realized, since the length of the first section can be adjusted very precisely. This can be achieved in a relatively simple and low-effort manner by first producing the current supply element over its entire length with the material core, the layer with the amalgam-forming material and the layer formed above it with the material inhibiting the formation of amalgam, and then with the situation-specific outer layer which inhibits the formation of amalgam Material for generating the first section is removed or removed.

However, production of the power supply element may also be realized by first forming around the material core the amalgam forming material layer and then applying only the layer in which the second portion is to be formed to the layer comprising the comprising amalgam formation inhibiting material. Specific removal of the amalgam-forming-inhibiting material to produce the first portion of the elongated portion of the current delivery element is not required in this approach.

It may also be provided that the first portion of the power supply element is butt welded to the second portion of the power supply element. In this case, the part consists of a uniform material, which does not tend to amalgamation and can be easily connected to the glass used in the lamp. Such an alloy is e.g. given by material number 2.4486 (NiFe47Cr6).

Preferably, the material core of the power supply element comprises iron and nickel. In particular, it is provided that the material core consists of iron and nickel. It proves particularly advantageous if the proportion of nickel in the core material is between 30% by weight and 60% by weight, in particular between 35 and 45% by weight, in particular 42% by weight.

The layer thickness of the amalgam-forming material is preferably chosen so that the amount of the amalgam-forming material resulting therefrom and from the length of the first section, in interaction with the working amalgam, can be between 0.02 and 0.1 mg Hg at room temperature per 100 ml lamp volume. This corresponds approximately to twice to 10 times the value of the optimum Hg vapor pressure which should be set in the equilibrium state of the lamp. By means of these layer thickness ratios, a corresponding basic thickness of the power supply element can be made possible and, on the other hand, the desired functionalities in the corresponding sections can be achieved particularly well without excessive power supply lines being created and undesirable amalgamations or too little amalgam formation at the corresponding sections would occur.

Preferably, the amalgam-forming material comprises copper. In particular, the copper content of the amalgam-forming material is between 20 and 50 percent by weight, in particular between 20 and 30 percent by weight, in particular 25 percent by weight. Preferably, such a use and addition of copper due to its material properties, a liquefaction in the lamp operation can be prevented. Such liquefaction occurs, for example, in indium during lamp operation. As a result, a creep of the copper material can be avoided, whereby the functionality of the lamp can be substantially increased. In particular, the amount of copper should be such that it is capable of binding about 0.05 to 0.1 mg Hg at equilibrium.

Preferably, the amount of the amalgam-forming material can be adjusted depending on the length of the first section.

Preferably, the first portion of the elongated portion of the power supply element is an end portion of the power supply element. In particular, the first portion is formed as an elongated rod which is bent to hold the electrode.

An electrode frame according to the invention comprises at least one power supply element according to the invention or an advantageous embodiment thereof.

Furthermore, the invention relates to a discharge lamp, in particular a low-pressure discharge lamp, which has at least one electrode frame with one or more power supply elements according to the invention or advantageous embodiments thereof. In particular, the discharge lamp is designed as a low-pressure discharge lamp.

Brief description of the drawings

Fig. 1

ein erfindungsgemäßes Elektrodengestell gemäß einem Ausführungsbeispiel;

Fig. 2

ein Stromzuführungselement des Elektrodengestells gemäß Fig. 1 in einer Seitenansicht; und

Fig. 3

eine Querschnittdarstellung des Stromzuführungselements gemäß Fig. 2.

An embodiment of the invention will be explained in more detail with reference to schematic drawings. Show it:

Fig. 1

an inventive electrode frame according to an embodiment;

Fig. 2

a power supply element of the electrode frame according to Fig. 1 in a side view; and

Fig. 3

a cross-sectional view of the power supply element according to Fig. 2 ,

Preferred embodiment of the invention

In the figures, identical or functionally identical elements are provided with the same reference numerals.

Further features and embodiments of the invention will become apparent from the claims, the figures and the description of the figures. The features and combinations of features mentioned above and listed below, in particular those in the figures and the description of the figures, can be used not only in the respectively specified combination but also in other combinations or in isolation without departing from the scope of the invention.

In Fig. 1 is shown in a schematic simplified representation of an electrode frame 1, which is arranged for example in a low-pressure discharge lamp. The electrode frame 1 comprises a first power supply element 2 and a second power supply element 3. The power supply elements 2 and 3 are configured as rod-shaped elongate parts and in particular represent a wire-like configuration. The shaping of the power supply elements 2 and 3 in the embodiment according to FIG Fig. 1 is merely exemplary and may also be provided in another embodiment. The electrode frame 1 further comprises an electrode 4, which is designed as a lamp filament. The electrode 4 is connected to end portions 5 and 6 of the power supply elements 2 and 3 by terminals. Distances too These front end portions 5 and 6, the power supply elements 2 and 3 are connected to a glass bead 7.

The power supply element 2 comprises a first section 8 and a second section 9 immediately adjacent thereto. The first section 8 is substantially shorter than the second section 9. The first section 8 has an amalgam-forming material on the outside. In the second section 9, a material protecting against amalgam formation is provided on the outside. In a corresponding manner, the sections 10 and 11 of the second power supply element 3 are formed.

The first two sections 8 and 10 are directly connected to the electrode 4 and formed for clamping the electrode 4.

In Fig. 2 is shown in a schematic side view of the power supply element 2 alone, wherein by way of example the position of the electrode 4 is shown. The first portion 8 represents an upper end portion of the power supply element 2 and thus the end portion 5. As shown in FIG Fig. 2 can be seen, this section 8 is bent so that the electrode 4 is clamped therebetween.

For further explanation of the structure of the power supply element 2 is now on Fig. 3 Reference is made in which a cross-sectional view of the section line AA according to Fig. 2 is shown. The sectional plane is thus formed perpendicular to the plane of the figure.

The power supply element 2 is multicomponent both in the first section 8, as well as in the second section 9 and multilayer structure, wherein in this context, the first layer or the first material region is formed as a material core 12. The material core 12 has as material iron and nickel, wherein the nickel content is about 42 weight percent.

Around the material core 12, a layer 13 is formed, which has the amalgam-forming material. In particular, copper is provided as the amalgam-forming material, and this is realized with a weight percentage of 25% in this layer 13.

In the first section 8, no further layer is formed on the layer 13 surrounding the material core, so that the amalgam-forming material in the layer 13 is thus free on the outside and on the outside.

In the second section 9, a further layer 14 is formed on this layer 13 surrounding the material core 12, which layer comprises the material suppressing amalgam formation. In this connection, in the layer 14, as the amalgam-forming suppressing material, nickel is provided. The layer thickness of the layer 14 is substantially thinner than the layer thickness of the layer 13. In particular, the layer thickness of the layer 14 is less than 20 .mu.m, in particular between 1 .mu.m and 5 .mu.m.

Preferably, the amount of the amalgam-forming material is adjusted depending on the length of the first portion 8, in which respect an extremely precise adjustment is possible.

In the embodiments shown, therefore, the amalgam-forming material is integrated directly into the power supply elements 2 and 3, so that it is no longer necessary to attach a separated metal sheet as a flag to the glass bead 7 or to one of the power supply elements 2 or 3.

Claims (15)

Power supply element for an electrode (4), which is elongated,
characterized in that
the elongated part of the power supply element (2, 3) has a first section (8, 10) which has an amalgam-forming material on the outside. Power supply element according to claim 1,
characterized in that
the first portion (8, 10) is provided for connection to the electrode (4). Power supply element according to claim 1 or 2,
characterized in that
the elongated part of the power supply element (2, 3) has the first section (8, 10) which has an amalgam-forming material on the outside, and a second section (9, 11) which has a material which suppresses amalgam formation on the outside. Power supply element according to claim 3,
characterized in that
the two sections (8 to 11) of the elongated part of the power supply element (2, 3) directly adjoin one another. Power supply element according to one of claims 3 or 4,
characterized in that
the first section (8, 10) is designed to clamp the electrode (4). Power supply element according to one of claims 3 to 5,
characterized in that
the amalgam formation suppressing material comprises nickel. Power supply element according to one of claims 3 to 6,
characterized in that
in the second section (9, 11), the material inhibiting the formation of amalgam is formed with a layer thickness of less than 10 μm, in particular between 1 μm and 5 μm. Power supply element according to one of claims 3 to 7,
characterized in that
the power supply element (2, 3) has a material core (12) surrounded by a layer (13) with an amalgam-forming material, wherein the amalgam-forming material in the second section (9, 11) of a layer (14) of the amalgam formation suppressing Surrounded by materials. Power supply element according to claim 8,
characterized in that
the material core (12) comprises iron and nickel, in particular consisting of iron and nickel. Power supply element according to claim 9,
characterized in that
the proportion of nickel in the material core (12) is between 30 and 60 percent by weight, in particular between 35 and 45 percent by weight, especially 42 percent by weight. Power supply element according to one of claims 3 to 10,
characterized in that
the amount of amalgam-forming material is such that, in conjunction with the working amalgam, between 0.02 and 0.1 mg Hg per 100 ml lamp volume can be absorbed at room temperature. Power supply element according to one of the preceding claims,
characterized in that
the amalgam-forming material comprises copper. Power supply element according to claim 12,
characterized in that
the amalgam-forming material has a copper content of between 20 and 50 percent by weight, in particular between 20 and 30, in particular 25. Power supply element according to one of the preceding claims,
characterized in that
the first portion (8, 10) of the elongated portion of the power supply element (2, 3) is an end portion (5, 6) of the power supply element (2, 3), and in particular the first portion (8, 10) is formed as an elongated rod, which is bent to hold the electrode (4). Electrode frame for a discharge lamp with at least one power supply element (2, 3) according to one of the preceding claims.

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