Inside current conductor for halogen-filled incandescent lamps especially lamps manufactured with curved tube enclosure and halogen-filled incandescent lamp made with the inside current conductor

Abstract: In an internal current conductor for halogen filled incandescent lamps at least two spiralized members (1, 2) and an elongated part (3) forming a series assembly (4) are applied, wherein the series assembly (4) is at least partly made of a wire of lower electric resistance than that of the wire of the incandescent body. In a halogen-filled incandescent lamp, comprising a curved tube enclosure (5) made of a translucent material and enclosing a gas filling, an incandescent body (6) made by spiralization from a tungsten wire of circular cross-section, the incandescent body (6) being arranged within the enclosure (5), means for energizing (8, 9) the incandescent body (6) and two inside current conductors (4) for connecting the incandescent body with the energizing means (8, 9). Each internal current conductor consists of a first and a second spiralized member (1, 2) and an elongated part (3) forming together a series assembly (4), the series assembly (4) being connected via the second spiralized member (2) with the incandescent body (6) and via the first spiralized member (1) with the energizing means (8, 9), the series assembly (4) being at least partly made of a wire having cross-sectional area exceeding that of the tungsten wire forming the incandescent body (6).

Description: The present invention refers to an internal current supply conductor applicable in halogen-filled incandescent lamps closed by flattening, particularly lamps manufactured with a curved tube enclosure. It refers also to a halogen-filled incandescent lamp, comprising a curved tube enclosure made of a translucent material, closed advantageously by flattening and enclosing a gas filling including a halogen element and a noble gas, an incandescent body made by spiralization from a tungsten wire of circular cross-section, the incandescent body being arranged within the enclosure, means for energizing the incandescent body sealed preferably by the flattening and two internal current supply conductors for connecting the incandescent body with the energizing means. According to the general practice of manufacturing halogen-filled incandescent lamps comprising a translucent enclosure, a helical (spiralized) incandescent body arranged within the enclosure and made of tungsten and means for energizing the incandescent body connnectable to an electric supply source. a halogen element is introduced into the gas space of the lamp. This halogen element is intended to take part in a chemical reaction with the metallic tungsten vapourized from the incandescent body which would otherwise be condensed on different surface parts of the enclosure which are obviously cooler than the incandescent body. The reaction results in a tungsten halide which in given conditions is generally a gaseous compound. The tungsten halide undergoes decomposition on the surface of the incandescent body, thereby transporting tungsten back to the incandescent body and the halogen element is released. The halogen taking part in the process cycle depicted above hinders the process of blackening of the enclosure and assures an increase of the life duration of the tungsten helical body. In order to minimize the effects negatively influencing the mentioned process cycle it is very important to manufacture the enclosure in a manner such that on its inner surface no, or only a minimized, area remains where the temperature does not exceed the temperature of condensation of the tungsten halide. The mentioned process cycle can take place only when conditions are assured wherein the tungsten halide can easily move within the gas space. When the temperature of the enclosure is concerned, this can be achieved without difficulties at such a high value, but there are problems when this is to be assured on the remaining parts of the lamp and especially at the ends of the helical incandescent body. The problem can be solved in principle in two ways, i.e. by passive and by active protection. Passive protection means overdimensioning the parts within the limits allowed by the possibilities, for example either a helical body is arranged as a protecting cover on the so-called interval, i.e. on the coldest parts, or the helical incandescent body is completed in the space surrounded thereby or is covered with a thick current conducting wire. Such solutions are described e.g. in the patent documents GB-PS 1,254,616 or DE-OS 3,124,218. In the methods of active protection the temperature is increased by applying appropriate heating means acting on predetermined surfaces. The present invention refers to the field of the passive protection and wishes to solve a further problem in this field, especially a problem playing an important role in the case of lamps manufactured with a curved tube enclosure. In halogen-filled lamps manufactured with curved circular, U- or multiangular shaped enclosures, e.g. in infra-red lamps the internal current conductors arranged within the enclosure may not have elongated straight sections (however, this would be required by the shape of the enclosure) because their temperature would be sufficiently low so as to ensure conditions of condensation of the tungsten halide. On the contrary, if the current conductors are replaced by respective "incandescent" bodies, a construction would be created which is characterized by disadvantageous performance parameters, and especially by low effectiveness. Moreover, the process of arranging and fixing the helical incandescent body in the curved tube enclosure of the halogen-filled incandescent lamp would be very difficult and even impossible if the two ends of the active helical incandescent body were connected with an elongated inside current conductor of relatively high rigidity. Hence, an aim of the invention is to provide a solution whereby the incandescent body applied in a halogen-filled incandescent lamp manufactured with a curved tube enclosure may simply be arranged in the enclosure and the temperature of the internal current supply conductors is high enough to exclude condensation of the tungsten halide and low enough to be much lower than the temperature of the helical body during normal operating the lamp. For attaining the above aim an internal current supply conductor of novel shape has been elaborated. Hence, the present invention provides an internal current conductor for incandescent lamps having a halogen filling, especially lamps manufactured with a curved tube enclosure, characterised by consisting of at least two spiralized members and one elongated part forming a series assembly, the series assembly being adapted for connection on one side with an incandescent body arranged within the enclosure of the halogen - filled incandescent lamp and on the other side with means for energizing the incandescent body, wherein the series assembly is at least partly made of a conductor of lower electric resistance than the conductor of the incandescent body of the lamp. Advantageously, the series assembly consists of two spiralized members and the elongated part, the elongated part serving for connection to the means for energizing and the spiralized members having different diameters, the first spiralized member being connected with the elongated part and having an outer diameter exceeding the outer diameter of the second spiralized member, the outer diameter of the latter being at most equal to the outer diameter of the incandescent body. Generally the series assembly is made of a wire thicker than the wire of the incandescent body. In an especially preferred embodiment of the internal current supply conductor according to the invention the series assembly is made of a tungsten wire of circular cross-section and the diameter of the wire of the series assembly is at least about 1.4 times greater than the diameter of the tungsten wire of the incandescent body and the greatest outer diameter of the first spiralized member is at least about twice and at most about 9.6 times the outer diameter of the incandescent body. Further, according to the invention, there is provided a halogen-filled incandescent lamp, comprising a curved tube enclosure made of a translucent material and enclosing a gas filling including a halogen element and a noble gas, an incandescent body made by spiralization of a tungsten wire of substantially circular cross-section, the incandescent body being arranged within the enclosure, means for energizing the incandescent body and two internal current supply conductors for connecting the incandescent body with the energizing means, characterised in that each internal current supply conductor consists of a first and second spiralized member and an elongated part forming a series assembly, the series assembly being connected via the second spiralized member with the incandescent body arranged within the enclosure and via the first spiralized member with the energizing means, the series assembly being at least partly made of a wire having a cross-section area exceeding the cross-section area of the tungsten wire forming the incandescent body, wherein generally tungsten is applied for manufacturing the wires of the series assembly. The connection between the second spiralized member and the incandescent body may be ensured in an especially advantageous way if the second spiralized member is at least partly overlapped by the incandescent body. For practical purposes it is preferred to realize the incandescent lamp of the invention in such a way that the first spiralized member is made with an outer diameter exceeding the outer diameter of the second spiralized member, the outer diameter of the latter being at most equal to the outer diameter of the incandescent body, and further advantageously the series assembly is made of a wire of circular cross-section and the diameter of the wire of the series assembly is substantially at least 1.4 times greater than the diameter of the tungsten wire of the incandescent body and the greatest outer diameter of the first spiralized member is substantially at least twice and substantially at most 9.6 times the outer diameter of the incandescent body. The invention will be further described in greater detail with reference to the drawing showing by way of example only a preferred embodiment of the lamp realized by application of the present invention. In the drawing: Figure 1 illustrates schematically a halogen-filled incandescent lamp equipped with the novel internal current conductor of the invention and manufactured with a tube enclosure of circular shape flattened on its two ends, and Figure 2 illustrates an advantageous realization of the internal current conductor. The present invention will be shown in more detail with reference to an incandescent lamp equipped with an enclosure 5 (FIG. 1) made of a translucent material and having a substantially circular shape. The enclosure 5 constitutes an assembly of a curved tube 15 and two elongated, substantially parallel input tube sections 10 connected with the curved tube 15. In the substantially circular curved tube 15 a helically shaped incandescent body 6 is supported on rings 7. The elongated tube sections 10 receive internal current supply conductors realized according to the present invention and at their free ends in flattened tube sections 11 respective means for energizing the incandescent body 6. Generally, each means for energizing includes a molybdenum foil (ribbon) 8 coupled on one side with the internal current supply conductor maintained in connection with the incandescent body 6 and, on the other side, with outer current lead-ins 9. The internal current supply conductor is constituted by a series assembly 4 consisting of at least two helical parts of advantageously different diameters and an elongated part 3 connected to the molybdenum foil 8. As shown in FIG. 1 a series assembly 4 comprising two helical parts is most preferred. It includes in connection with the elongated part 3 a middle section constituted by a first spiralized member 1 and an end section formed by a second spiralized member 2 coupled with the incandescent body 6. The second spiralized member 2 is partly or wholly overlapped by the incandescent body 6. Generally the series assembly 4 is made of tungsten wire. Before manufacturing the lamp an internal assembly should be prepared, the assembly including in series connection the incandescent body 6 with the supporting rings 7, the two series assemblies 4 as internal current supply conductors according to the invention, the molybdenum foils 8 and the outer current lead-ins 9. This assembly is arranged within the enclosure 5 by dragging it from one end of the enclosure 5 to the other end, i.e. from the end of one of the elongated tube sections 10 to the other end thereof. This operation of transporting the series assembly through the interior of the enclosure 5 is only possible when the series assembly 4 as a whole unit is sufficiently flexible and resilient. This process should be facilitated by applying the internal current supply conductor manufactured according to the present invention and equipped with the first spiralized member 1 as shown in more detail in FIG. 2. After arranging the series assembly 4 within the enclosure 5 the process of manufacturing the lamp up to its being ready for operation should be completed by applying the general practice followed in this field of industry. Returning to the internal current supply conductor formed according to the present invention and illustrated in more detail in Fig. 2, it may be seen that the series assembly 4 includes the elongated part 3 of wire (conductor) of diameter d₁ connected, generally by welding, at one end to the molybdenum foil 8, and at the other end to the first spiralized member 1 of length L₁ and outer diameter D₁. The second spiralized member 2 connected to the incandescent body 6 is of length L₂ and constitutes a transitional section of diameter smaller than the diameter D sp of the incandescent body 6 which is made of a wire of diameter d sp . The outer diameter D₁ of the first spiralized member 1 is generally four times greater than the outer diameter of the incandescent body 6, but it can be smaller or bigger than this value, what is here important is only that its temperature during operation of the lamp should be high enough to exclude the process of condensing the tungsten halide and low enough to avoid radiation. The elongated part 3 of the series assembly 4 of the internal current supply conductor and generally the whole series assembly 4 is manufactured from a conductor of diameter d₁ exceeding, and especially at least 1.4 times the diameter d sp of the conductor applied for the incandescent body 6 in order to reduce its electric resistance in comparison with the resistance of the incandescent body 6. Of course, this reduction can be ensured by wires of non-circular cross-sections, too, when the electric resistance is determined on the basis of the surface area of the cross-sections or by applying wires of different materials, if appropriate. The upper limit of the wire thickness is determined by the condition that this wire should show sufficient flexibility for carrying out the step of spiralizing. This is especially important concerning the second spiralized member 2 which requires to be made of a wire of high resiliency. The outer diameter of the second spiralized member 2 is at most as large as the outer diameter D sp of the incandescent body 6; generally, it is smaller. The spiralized member 2 is generally shorter than the first spiralized member 1: it should be connected with the end of the incandescent body 6 in an electrically conductive way. According to our experience, it is especially advantageous to prepare the first spiralized member 1 with an outer diameter D₁ of at least 2.0 times and at most 9.6 times the outer diameter D sp of the incandescent body 6. Example A 150 V and 800 W halogen-filled lamp for heat radiation is manufactured. The lamp is equipped with an enclosure 5 made of quartz and having a substantially circular shape with a diameter of about 200 mm. The inner diameter of the tube of the enclosure is substantially 15 mm. The incandescent body 6 of the lamp was made of a tungsten wire of 0.25 mm diameter and spiralized to have an outer diameter 1.29 mm, i.e. D sp = 1.29 mm. The helical shaped incandescent body is equipped with supporting rings 7. The current is fed to the incandescent body 6 by the internal current supply conductor 4 made according to the present invention. This internal current supply conductor 4 was made of a tungsten wire having a 0.37 mm diameter, i. e. d₁ = 0.37 mm. Hence, the wire from which the internal current supply conductor 4 was prepared is about 1.5 times thicker than the wire of the incandescent body 6. As is shown in FIG. 2, in this case the internal current supply conductor 4 realized according to the invention consists of three clearly distinguishable parts forming one continuous conductor. The outer diameter of the spiralized part 1 amounts about 5.2 mm, i.e. D₁ = 4 x D sp = 5.2 mm. The outer diameter of the second spiralized member 2 corresponds substantially to the outer diameter of the incandescent body 6. The length of the first spiralized part 1 is about 32 mm, i. e. L₁ = 32 mm, the length of the second spiralized part 2 is substantially 6 mm, i.e. L₂ = 6 mm, and the length of the elongated part amounts about 19 mm, i.e. L = 57 mm. The internal current supply conductor 4 described above is connected in a current conductive way with the incandescent body 6 equipped with the supporting rings 7 and the whole assembly obtained is mounted within the curved quartz enclosure. The lamp is manufactured thereafter by the usual steps of manufacturing. The lamp has a gas filling including bromine as a halogen element. Besides bromine, krypton is also present. The heat radiating lamp was connected to an appropriate current source for operation. During operation no deposition could be experienced on the neck part of the lamp. Although the lamp of the present invention has been shown with reference to one of the most advantageous embodiments, of course the invention is not limited to that. The invention is determined by the claims and within the scope of protection afforded by the claims an artisan skilled in this field can create many embodiments and these modifications are all claimed hereby.

Claims: Internal current supply conductor for halogen filled incandescent lamps, especially lamps manufactured with a curved tube enclosure, characterized by consisting of at least two spiralized members (1, 2) and one elongated part (3) forming a series assembly (4), the series assembly (4) being adapted for connection on one side with an incandescent body (6) arranged within the enclosure (5) of the halogen-filled incandescent lamp and on the other side with means for energizing (8, 9) the incandescent body, wherein the series assembly (4) is at least partly made of a conductor of lower electric resistance than the conductor of the incandescent body. The internal current supply conductor according to claim 1, characterized in that the series assembly (4) consists of two spiralized members (1, 2) and the elongated part (3), the elongated part (3) serving for connection to the energizing means (8, 9) and the spiralized members (1, 2) having different diameters, the first spiralized member (1) being connected with the elongated part (3) and having an outer diameter (D₁) exceeding the outer diameter of the second spiralized member, the outer diameter of the latter being at most equal to the outer diameter (D sp ) of the incandescent body (6). The internal current supply conductor according to claim 1 or 2, characterized in that the series assembly (4) is made of a wire thicker than the wire of the incandescent body. The internal current supply conductor according to claim 2 or 3, characterized in that the current supply conductor is made of tungsten wire having a circular cross-section and the diameter (d₁) of the wire of the series assembly (4) is at least about 1.4 times greater than the diameter (d sp ) of the tungsten wire of the incandescent body (6) and the greatest outer diameter (D₁) of the first spiralized member (1) is at least about twice and at most about 9.6 times the outer diameter (D sp ) of the incandescent body. Halogen-filled incandescent lamp, comprising a curved tube enclosure (5) made of a translucent material and enclosing a gas filling including a halogen element and a noble gas, an incandescent body (6) made by spiralization from a tungsten wire of circular cross-section, the incandescent body (6) being arranged within the enclosure (5), means for energizing (8, 9) the incandescent body (6) and two internal current supply conductors (4) for connecting the incandescent body with the energizing means (8, 9), characterized in that each internal current supply conductor (4) consists of a first and a second spiralized member (1, 2) and an elongated part (3) together forming a series assembly (4), the series assembly being connected via the second spiralized member (2) with the incandescent body (6) arranged within the enclosure (5) and via the first spiralized member (1) with the energizing means (8, 9), the series assembly (4) being at least partly made of a conductor of a cross-sectional area exceeding that of the tungsten wire forming the incandescent body (6). The incandescent lamp according to claim 5, characterized in that the second spiralized member (2) is at least partly overlapped by the incandescent body (6). The incandescent lamp according to claim 5 or 6, characterized in that the first spiralized member (1) is made with an outer diameter (D₁) exceeding the outer diameter of the second spiralized member (2), the outer diameter of the latter being at most equal to the outer diameter (D sp ) of the incandescent body (6). The incandescent lamp according to any of claims 5 to 7, characterized in that the series assembly (4) is made of a wire of circular cross-section the diameter (d₁) of which is at least substantially 1.4 times greater than the diameter (d sp ) of the tungsten wire of the incandescent body (6) and the greatest outer diameter (D₁) of the first spiralized member (1) is substantially at least twice and substantially at most 9.6 times the outer diameter (D sp ) of the incandescent body (6). The incandescent lamp according to any of claims 5 to 8, characterized in that the series assembly (4) is made of a tungsten wire.

Inventors: CZAKO EMIL, LOSONCZI ZOLTAN, ORSANYI GYOERGY, SZABO GYOERGY, CZAKO, EMIL, LOSONCZI, ZOLTAN, ORSANYI, GYOERGY, SZABO, GYOERGY, Czakó, Emil, Losonczi, Zoltán, Orsányi, György, Szabò, György
Applicants: TUNGSRAM RESZVENYTARSASAG
Application year: 1990
Main classification: H01K1
IPC codes: H01K1