Patent Application
20140111080
Various embodiments relate to methods for producing a winding for producing an electrode for discharge lamps, windings for producing an electrode for discharge lamps and methods for producing an electrode for discharge lamps.
In discharge lamps as described, for example, in US 2004/0070324 A2, the aim is to increase the emitter quantity on the electrode filament in order to thus achieve a longer life or lighting duration of the discharge lamp. For this purpose, US 2004/0070324 A2 proposes providing a double-filament or triple-filament wire structure, by which the emitter material which is, for example, a (Ba, Ca, Sr) 0 material (applied as (Ba, Ca, Sr) CO3 material) is held. Owing to the increase in volume achieved by means of the filament wire structure, a greater quantity of emitter material can be held between and on the wires of the filament wire structure.
In order in the process to achieve a relatively large radial distance of a wrapping wire from a primary core wire even in the primary filament structure, an additional, lost core wire is provided which runs parallel to the primary core wire in order thus to achieve overall a core with a total diameter including the diameters of the primary core wire and the lost core wire.
During winding of such a primary filament structure around a secondary core wire, however, it is generally not possible to achieve a uniform radial distance of the primary core wire from the secondary core wire, for which reason the electrical resistance of the filament structure is uneven in the longitudinal direction of said filament structure. In order to keep the resistance distribution within a permitted tolerance framework in the longitudinal direction of the filament structure, therefore, the maximum diameter of the lost core wire of the primary filament structure therefore cannot be selected to be too great.
Various embodiments provide methods for producing a winding for producing an electrode for discharge lamps and windings for producing an electrode for discharge lamps in order to overcome the problems encountered in the prior art.
Various embodiments provide a method for producing a primary winding for producing an electrode for discharge lamps, includes: providing a primary core wire, which has a longitudinal axis and consists of an electrically conductive material, winding a cladding wire around the primary core wire along the longitudinal axis of the primary core wire, with the result that the cladding wire forms a primary core wire cladding surrounding the primary core wire, and winding a wrapping wire, which consists of an electrically conductive material, for example, around the primary core wire cladding at a radial distance from the primary core wire along the longitudinal axis of the primary core wire.
The primary core wire and the wrapping wire consist of a material with good thermal resistance, such as tungsten (W), for example. The cladding wire, which, as will be explained later, is a lost cladding wire, likewise consists of a material with good thermal resistance but which is less resistant to solvents or corrosive agents, for example acids, than the material of the primary core wire and the wrapping wire, such as molybdenum (Mo), for example. The lost cladding wire can also consist of iron (Fe). The good thermal resistance of the primary core wire, the wrapping wire and the cladding wire makes it possible, once the primary winding for its part, as will be explained below, for example, is wound around a further core wire in the longitudinal direction of the primary core wire, to reduce the material stresses which may thus be produced in the primary winding via heat treatment, for example annealing. The lower resistance of the material of the cladding wire to corrosive agents makes it possible to remove this cladding wire from the primary core wire and the wrapping wire again, for example via dissolving in a solvent/corrosive agent, for example in an acid bath, without the primary core wire and the wrapping wire being damaged thereby. A suitable acid for the acid bath is, for example, an acid mixture such as the acid described in DE2933430C2, for example, which contains from 30 to 60% by weight of nitric acid and from 20 to 50% by weight, for example 28 to 42% by weight, of sulfuric acid and water as the remainder. The cladding wire generally thus represents a lost wire, as mentioned already above, which is used for enlarging the radial distance of the wrapping wire from the primary core wire, wherein, once the cladding wire has been removed (for example separated) from what is left of the (remaining) winding structure, which is formed by the primary core wire and the wrapping wire, a receiving area for receiving an emitter material is formed. In this case, the emitter material can be an emitter material as described, for example, in the abovementioned US 2004/0070323 A1.
By virtue of the fact that the cladding wire has been wound along the primary core wire, i.e. the cladding wire has been wound around the primary core wire for example in helical fashion, wherein the windings of the cladding wire do not overlap one another or overlap one another uniformly, for example, the primary core wire cladding thus achieved which is formed by the cladding wire has a substantially identical thickness, wherein the primary core wire is arranged (substantially) centrally. Therefore, the wrapping wire always has substantially the same radial distance from the primary core wire, even when the primary winding achieved in this way for its part is wound around a secondary core wire (for example likewise in helical fashion) since the primary core wire cannot slide relative to the cladding wire in the radial direction of said primary core wire. Thus, the diameter of the cladding wire can be selected to be very large, as a result of which a correspondingly large radial distance between the wrapping wire and the primary core wire can be achieved without the uniformity of the distribution of the electrical resistance of the final winding structure being impaired. The cladding wire is wound helically around the primary core wire with a substantially constant helix pitch, for example. In addition, the cladding wire is wound directly onto the primary core wire, for example.
The wrapping wire consists of an electrically conductive material which, as mentioned above, likewise has good thermal resistance, for example of the same material as the primary core wire and therefore of tungsten (W), for example. The wrapping wire has, for example, a smaller diameter than the primary core wire, for example a diameter that is at least 50% smaller than the primary core wire. The wrapping wire is generally wound helically, for example without any overlap of the turns or with uniform overlapping of the turns, around the primary core wire cladding. The wrapping wire is wound for example helically with a substantially constant helix pitch around the primary core wire cladding. In addition, the wrapping wire is wound, for example, directly onto the primary core wire cladding.
In accordance with one embodiment, during winding of the cladding wire, the turns of the cladding wire are arranged directly adjacent to one another, preferably adjoining one another, in the direction of the longitudinal axis of the primary core wire. As a result, a substantially closed lateral surface is achieved in order to keep the radial distance of the wrapping wire from the primary core wire the same in an improved and more precise manner.
In accordance with one embodiment, during winding of the wrapping wire, the turns of the wrapping wire are arranged at an axial distance from one another in the direction of the longitudinal axis of the primary core wire, which axial distance is greater than an axial distance between the turns of the cladding wire in the direction of the longitudinal axis of the primary core wire. The axial distance is, for example, greater than the diameter of the wrapping wire, for example more than twice as large.
In accordance with one embodiment, provision can be made for the wrapping wire to be wound around the primary core wire cladding counter to the direction of the cladding wire, i.e. for the helix pitch of the cladding wire relative to the primary core wire to have a mathematical sign which is different in comparison with the helix pitch of the wrapping wire relative to the primary core wire, wherein the absolute size of the helix pitch can be different. Thus, it is possible to ensure that the wrapping wire does not come to lie in a region in which two adjacent turns of the cladding wire adjoin one another and the radial distance from the primary core wire is smaller than a diameter of the cladding wire. Thus, a particularly uniform radial distance of the wrapping wire from the primary core wire can be provided.
In addition, the disclosure provides a method for producing a secondary winding for producing an electrode for discharge lamps, having the following steps: providing a secondary core wire which has a longitudinal axis, producing a primary winding in a manner described above, and winding the primary winding in the longitudinal direction of the primary core wire around the secondary core wire along the longitudinal axis of the secondary core wire.
The secondary core wire is generally a lost wire, corresponding to the cladding wire, with the result that, corresponding to the cladding wire, it consists of a material which is less resistive than the material of the primary core wire and the wrapping wire, for example a material which is less resistive to solvents or corrosive agents, such as acid, for example. The secondary core wire consists of the same material as the cladding wire, for example, and thus consists of molybdenum (Mo), for example.
The primary winding is generally wound helically, for example with a constant helix pitch, around the secondary core wire in the longitudinal direction of the primary core wire of said primary winding, wherein the primary winding is wound directly onto the secondary core wire, for example. The turns of the primary winding are arranged, for example, at an axial distance from one another along the longitudinal axis of the secondary core wire, which axial distance is selected, for example, in such a way that the ratio (pitch factor) of the pitch of the primary winding around the secondary core wire (this pitch corresponds to the axial length of a turn of the primary winding around the secondary core wire when measured in the longitudinal direction of the secondary core wire) is less than 2 owing to the diameter of the primary winding per se (measured transversely to the longitudinal axis of the primary core wire).
In the secondary winding manufactured in this way, heat treatment, for example annealing, can be used to reduce (wire material) stresses in the secondary winding, and then in a further step the secondary core wire and the cladding wire can be removed, for example by means of dissolving or thereby separating (for example by means of acid) the secondary core wire and the cladding wire from the (remaining) winding structure, which is formed by the primary core wire and the wrapping wire. The emitter material can be applied to or introduced into the cavities in what is left of the (remaining) winding structure of the secondary winding, as a result of which a winding structure/overall structure is achieved which can be used as an electrode for a discharge lamp. Otherwise, the discharge lamp can be constructed as described, for example, in US 2004/0070324 A1, and can thus be a low-pressure discharge lamp or else a high-pressure discharge lamp, for example.
In order to provide an even larger volume for receiving emitter material, the disclosure provides a method for producing a tertiary winding for producing an electrode for discharge lamps, having the following steps: providing a tertiary core which has a longitudinal axis, producing a secondary winding in accordance with the method as described above, and winding the secondary winding in the longitudinal direction of the secondary core wire around the tertiary core along the longitudinal axis of the tertiary core.
The tertiary core may likewise be a tertiary core wire and may consist of, for example, a material as described above for the secondary core wire (i.e. Mo or Fe, for example) and consists of, for example, the same material as the secondary core wire and/or the cladding wire. In accordance with another embodiment, the tertiary core is a component part which is not lost and may therefore be reused (for example a winding machine mandrel) consisting of, for example, hard metal such as tungsten carbide, for example. The secondary winding is, for example, wound helically in the longitudinal direction of its secondary core wire, for example with a substantially constant helix pitch, along the tertiary core around said tertiary core, for example directly onto the tertiary core, wherein the turns can be arranged so as to adjoin one another or else at an axial distance (in the longitudinal direction of the tertiary core) from one another.
Once the tertiary winding has been manufactured in the manner described above, the cladding wire, the secondary core wire and the tertiary core in the form of a (lost) tertiary core wire can be removed from the (remaining) winding structure including the primary core wire and the wrapping wire in the manner described above for the cladding wire and the secondary core wire, and then emitter material can be introduced into the cavities in this remaining winding structure or applied onto the (remaining) winding structure in order to thus provide a winding structure which can be used as such as an electrode structure/electrode in a discharge lamp. When using a reusable tertiary core, the secondary winding which is wound around the tertiary core as described above, for example, is stripped from the tertiary core in the longitudinal direction thereof in order then to remove the cladding wire and the secondary core wire in the manner explained above, i.e. to separate it using an acid bath, for example.
The diameter of the primary core wire may be constant over its entire length. The same applies to the diameter of the cladding wire, the diameter of the wrapping wire, the diameter of the secondary core wire and the diameter of the tertiary core (wire).
In accordance with the disclosure, based on the above methods the following are also provided: a primary winding for producing an electrode for discharge lamps, with a primary core wire, which has a longitudinal axis and consists of an electrically conductive material which has high thermal resistance, for example (as explained above), a cladding wire (consisting of a material as explained above, for example), which is wound around the primary core wire along the longitudinal axis of the primary core wire (for example helically as explained above), with the result that the cladding wire forms a primary core wire cladding surrounding the primary core wire, a wrapping wire (consisting of a material and a structure, for example, as explained above), which is wound around the primary core wire cladding at a radial distance from the primary core wire along the longitudinal axis of the primary core wire (for example helically as explained above), also a secondary winding for producing an electrode for discharge lamps, with a secondary core wire (consisting of a material as explained above, for example), which has a longitudinal axis, and an above-described primary winding, wherein the primary winding is wound in the longitudinal direction of the primary core wire around the secondary core wire along the longitudinal axis of the secondary core wire (for example helically as explained above), and in addition a tertiary winding for producing an electrode for discharge lamps with a tertiary core (wire) (consisting of a material as explained above, for example), which has a longitudinal axis, and a secondary winding as described above, wherein the secondary winding is wound in the longitudinal direction of the secondary core wire around the tertiary core (wire) along the longitudinal axis of the tertiary core (wire) (for example helically as explained above).
In the case of the primary winding, the turns of the cladding wire can be arranged directly adjacent to one another, preferably adjoining one another, in the direction of the longitudinal axis of the primary core wire. In addition, in the case of the primary winding, the turns of the wrapping wire can be arranged at an axial distance from one another in the direction of the longitudinal axis of the primary core wire, which axial distance is greater than an axial distance between the turns of the cladding wire in the direction of the longitudinal axis of the primary core wire. The wrapping wire may also be wound in the opposite direction to the cladding wire when viewed in the direction of the longitudinal axis of the primary core wire around the primary core wire.
The respective core wire or core (primary core wire, secondary core wire and tertiary core (wire)) and/or the cladding wire and/or the wrapping wire consist(s) of an electrically conductive material, for example. The respective core wire and/or the cladding wire and/or the wrapping wire consist of a metal material, for example.
Various embodiments also provide:
A method for producing an electrode for a discharge lamp, having the following steps: producing a secondary winding as explained above by means of the associated method as explained above, removing the secondary core wire and the cladding wire (for example in a manner as described above) so as to form corresponding emitter material receiving cavities in the remaining winding structure formed by the primary core wire and the wrapping wire, and introducing an emitter material (for example as described above) into the emitter material receiving cavities, wherein, for example, the emitter material is introduced at least or substantially exclusively into the cavities produced by the removal of the secondary wire and the cladding wire.
A method for producing an electrode for a discharge lamp, having the following steps: producing a tertiary winding as described above by means of the method explained as above, removing (for example in a manner as described above) the secondary core wire, the tertiary core (wire) and the cladding wire so as to form corresponding emitter material receiving cavities in the remaining winding structure formed by the primary core wire and the wrapping wire, and introducing an (for example as described above) emitter material into the emitter material receiving cavities.
In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the disclosed embodiments. In the following description, various embodiments described with reference to the following drawings, in which:
The same reference symbols are used in the drawing for identical or similar features.
The following detailed description refers to the accompanying drawing that show, by way of illustration, specific details and embodiments in which the disclosure may be practiced.
The primary winding 1 has: a primary core wire 3, which has a longitudinal axis 5 and consists of an electrically conductive metal material with good thermal resistance (in this case W), a cladding wire 7, which consists of an electrically conductive metal material with high thermal resistance (in this case Mo), which is different from the material of the primary core wire 3 and is less resistant to corrosive agents than the material of the primary core wire 3, and which primary core wire is wound helically with small axial distances between the turns and directly around the primary core wire 3 along the longitudinal axis 5 of the primary core wire 3, with the result that the cladding wire 7 forms a primary core wire cladding 9 surrounding the primary core wire 3, and a wrapping wire 11, which is wound helically directly around the primary core wire cladding 9 at a radial distance RD from the primary core wire 3 along the longitudinal axis 5 of the primary core wire 1 and which consists of an electrically conductive metal material with a high thermal resistance (in this case W), which is more resistant to corrosive agents than the material of the cladding wire 9.
The turns of the cladding wire 7 of the primary core wire cladding 9 are arranged axially tightly adjacent to one another when viewed in the direction of the longitudinal axis 5 of the primary core wire 3. In contrast, the turns of the wrapping wire 11 are arranged at an axial distance AD from one another when viewed in the direction of the longitudinal axis 5 of the primary core wire 3. The turns of the cladding wire 7 are wound in the direction of the longitudinal axis 5 of the primary core wire 3 in opposite directions to the turns of the wrapping wire 11 in the direction of the longitudinal axis 5 of the primary core wire 3, i.e. the helix formed by the turns of the cladding wire 7 has a pitch with a different mathematical sign than the helix formed by the turns of the wrapping wire 11.
In order to produce, for example, an electrode for a discharge lamp, the secondary winding 21 shown in
The (remaining) winding structure provided with the (Ba, Ca, Sr) CO3 emitter material 37 in this way is then subjected to a thermal treatment in order to convert the (Ba, Ca, Sr) CO3 material (carbonate material) into (Ba, Ca, Sr) O emitter material 37 (oxide material). The conversion into the oxide is generally only performed when the subsequent lamp is exhausted, but before it is sealed (fused shut). The oxides are hygroscopic. Therefore, they are not resistant to air. The carbonate is applied and only when the lamp has been exhausted and flushed generally at least once, temperature is supplied via a current through the filament and the carbonate is converted into oxide. The resultant CO2 is exhausted. From this point on, it should not be possible for any air and primarily any moisture to arrive at the filament any more.
The (remaining) winding structure filled with the emitter material 37 (converted to oxide material) and including the primary core wire 3 and the wrapping wire 11 can be used in a discharge lamp 100 shown in longitudinal section as in
The method shown in
The method shown in
The method shown in
The method shown in
The method shown in
While the disclosed embodiments has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosed embodiments as defined by the appended claims. The scope of the disclosed embodiments is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 006 620.9 | Apr 2011 | DE | national |
The present application is a national stage entry according to 35 U.S.C. §371 of PCT application No.: PCT/EP2012/054356 filed on Mar. 13, 2012, which claims priority from German application No.: 10 2011 006 620.9 filed on April 1, 2011.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP12/54356 | 3/13/2012 | WO | 00 | 12/10/2013 |
