FR2470441A1 - ELECTRICAL LAMP WITH PINCH APLATI - Google Patents

Abstract

THE ELECTRIC LAMPS CONFORMING TO THE INVENTION HAVE A QUARTZ 1 GLASS BULB WITH AN APLATI 3 PINCH IN WHICH IS INSERTED A CURRENT INPUT 5, 10. OVER PART OF ITS LENGTH, THE CURRENT INPUT 5, 10 HAS AN INTERMEDIATE GLASS COATING 6, 9 BETWEEN THE ENDS OF WHICH THE PINCH GLASS 3 IS SEALED TO THE COATING 6, 9. ON EACH OF ITS LARGE SIDE FACES, THE APLATI PINCH SHOWS A RIB EXTENDING ABOVE EACH OF THE INPUTS OF CURRENT 5, 10 INSERTED IN THE CLAMP ON THE ENTIRE CLAMP PART OF THE SAID INPUTS. APPLICATION: LIGHTING.

Description

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  "Electric lamp with flattened pinch."

  The invention relates to an electric lamp comprising a quartz glass bulb, which is provided with

  current connected to an electrical element disposed in the

  hen, while passing hermetically through the wall of said bulb, and having over a part of its length a coating of an intermediate glass, between the ends

  which wall of the bulb is welded to said coating.

  Such a lamp is known from British Patent No. 710,434.

  In general, lamps with a

  high operating temperature are provided with a quartz glass bulb, substance by which is meant below, the glasses having at least 95% by weight of SiO2, and of current tungsten or molybdenum. These glasses have a coefficient of thermal expansion (about 7 x 10-7 K 1) which differs significantly from that of tungsten

  (45 x 10-7 K 1) and molybdenum (54 x 10-7 K). Being given

  Given these large differences in thermal expansion, it is generally customary to make the current inputs where they pass hermetically through the wall of the bulb in the form of a thin sheet to which a current inlet is welded. inside and an outside current input. During the realization of the welds and also during the sealing of the entries of current in the wall of the bulb, appears a certain rejects caused by

  rupture of the leaf. Always check the quality

  welds. The set of current inputs is too inflexible as a result of the presence of the sheet, so that it is difficult to position properly

  the internal current input to the bulb for mounting.

  Finally, the sheet limits the intensity of the current in the current input. However, just about every kind of lamps with a quartz glass bulb

  commercially available have the structure de-

  despite these drawbacks. Only in the lam-

  high current intensity, such as

  short-arc charge, which one is forced in practice to use a sealed wire as current input. It appears that

  There are economic and technological disadvantages that

  the use of wires sealed in the wall of the

hen of other types of lamps.

  According to said British Patent No. 710,434, a seal

  airtightness of the current inlet in the wall of the quartz glass bulb is obtained by applying to the sealing of a coating in a glass intermediate

  or in several intermediate glasses on the entrance of cou-

  and sealing said wall and said coating

  between the ends of said coating.

  However, it is particularly difficult and labo-

  to make a good weld between the wall of the

  hen and the coating of the current inlet. For this purpose, the quartz glass of the bulb to be formed must be sunk on the coating of the current inlet. It is true that the process can be speeded up by applying the quartz glasses against the glass coating, using

  tools, but this process is difficult to automate.

  On the other hand, it has been found that a pinch of the usual type in the lamps where a thin metal foil is used, applied around the glass coating, does not provide

  not a reliable closure and leads quite often to breakage.

  The invention aims to provide electric lamps comprising a quartz glass bulb provided with current inputs, lamps which have a robust structure,

  easy to carry out, which does not imply

  in practice the diameter of the current inputs.

  This object is achieved with lamps of the kind mentioned in the preamble because the bulb has at least one flattened nip in which is inserted at least one current input and which has, at each of these two

  large lateral faces, for each current input in-

  in the nip, a rib extending over the wire in question over the entire length of the pinched portion of

this last.

  Experiments have shown that these lamps exhibit

  a reliable structure, easy to achieve during a project

  automated shutdown, even in the case of using current inputs with a diameter of 0.6 to 0.8 mm. Contrary to the foregoing, it has been found that in many cases, the lamps, whose large lateral faces of the nip were not provided with such a rib, were subject to breakage, even upon cooling, immediately after

the realization of the pinch.

  The present invention is based on the following idea.

  Generally, by "intermediate glasses", there is

  instead of hearing glasses, whose coefficient of expansion

  The thermal connection is between the materials to be bonded, in this case the metal of the current inlet and the quartz glass of the bulb. Because, because of their high SiO 2 content, quartz glasses have

  a very low coefficient of thermal expansion and

  For a very high softening point, the intermediate glasses must have a lower SiO2 content to achieve a higher coefficient of expansion.

  high and simultaneously have a lower temperature.

softening.

  When making a flattened pinch, the intermediate glass has a temperature, which differs little from that of quartz glass. As a result, glasses

  intermediates have a relatively low viscosity.

  The pressure exerted by the pinch blocks and trans-

  by the quartz glass to the intermediate glass causes easy flow of the intermediate glass, which results in the damage, or even the partial disappearance

  of the coating of the current inlet, when

  a normal pinch in which the large faces

  side are not provided with a rib, as

  these clamping lamps according to the invention. In the finite nip, the current input is thus no longer surrounded by intermediate glass, which results in

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  tensions occurring in the quartz glass causing

the risk of breakage.

  However, the development, in the surface of the pine blocks,

  a groove, the location of which corresponds to that of the current inlet in the end always open

  of the bulb to be formed, allows to preserve, in the clamp-

  between the joined quartz glass surfaces, a cavity for the current inlet and its coating

intermediate glass.

  As is always the case during the deformation of the glass, it is also important here that the glasses can flow and fuse, which prevents the formation of acute angles where the glass surfaces meet. So,

  following the sealing process, it may be advantageous

  geux to submit the pinch to a post-heating.

  It has been found that the welding of the glasses is easy if, at the point of the pinch to be made, the quartz glass is provided with an intermediate glass coating. When

  pinching, simply solder this coat-

  the power supply wire, which is

  easier, thanks to the lower temperature

  softening of the intermediate glass.

  What is particularly important is that the lamps according to the invention lend themselves not only to an easy and automated realization and have a very reliable structure while allowing intensities of

  high current with low losses, but that their structure

  ture allows you to insert several

  in the pinch. This is obviously impossible in the known structure of the above-mentioned British patent,

  the fact that the sealing of the current inlet is there

metrics of revolution.

  In the case where the lamp according to the invention of the ty -

  example, a discharge lamp in the va-

  fear of high-pressure mercury, and that the electrical element

  that disposed in the bulb is constituted by a pair of main electrodes, it is possible that a pinch has, in addition to the current input connected to a main electrode, also a current input connected to

  an auxiliary electrode. When the lamp complies with the

  vention has a filament as an electric element, the lamp can be made with two pinches or with

  a single pinch, according to its application.

  It has been found that very good results are obtained with intermediate glasses having, in the temperature range between 30 and 8000C, an expansion coefficient (A) of between about 11 and 17 × 10 -7 -1 K). The following table mentions several examples of

  such glasses (composition expressed in% by weight).

_

  Sio2 TB2O3 To Cao cCa x 10 (K 1 to 86.9 9.0 4.1 i1 b 86.4 9.6 4.0 13 c 81.9 13.1 4.5 0.5 15 d 81.0 10.9 7.1 1.0 17

  Intermediate lenses can be sealed

  Conventional input to tungsten or molybdenum inlets to form a coating. Thus, starting from stem glass, the glass can be spread on the wire, using a flame. If the glass is available in tubular form, it can be slid on the wire and then sealed to the wire, for example by

inductive heating.

  In lamps where the hermetic seal is

  on a sheet inserted in the nip, the latter is hermetic only for a part of the length of the

  sheet between the ends of the neck entrance

  interior and the external power supply input

  die to the leaf. To ensure the mechanical anchoring of these

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  internal and external current inputs in the clamp-

  the length of the pinch must exceed

  that of the hermetic part.

  On the other hand, in lamps conforming to

  vention, the pinch is hermetic over the entire length of

  the pinch portion of the current input, which gives the lamps according to the invention pinches

  significantly shorter, allowing not only

  quartz glass, but also the realization of a smaller lamp. Thus, it is possible to use equipment of smaller volume and lower weight. U.S. Patent No. 3. 742.283 discloses an electric lamp, whose bulb is quartz glass and provided with a pinch, the portion of the current inputs applied in the nip being surrounded by a cermet. The upper side faces of the known lamp have a rib extending over the entrances

current.

  Despite some resemblance, there are

  essential differences between this lamp and that

  form to the invention. Said U.S. patent mentions that a single cermet coating is sufficient when the current inputs have a diameter of about 300 μm. If the thickness of the current inputs

  is 750 / um or higher, it is necessary to

  at least two coatings with coefficients

different dilatation.

  However, lamps with power wires

  current of 300 / u are exceptionally

  As a result, most lamps according to the US patent must have at least two cermet coatings on the current entrances. Of

  Moreover, cermets are difficult to treat.

  On the other hand, in lamps conforming to

  vention, just use a single coating, which is

  made of glass and is easy to apply.

  The cermets used according to said US patent are more viscous than quartz glasses, even at elevated temperatures, because they contain a high melting point metal such as tungsten. The intermediate glass used in the lamps according to the invention is less viscous than quartz glass because it has a lower content of SiO 2 in lamps according to the US patent.

  of America, a rib is applied to the lateral

  of the pinch above the current inlets to prevent the relatively low viscosity quartz glass from leaving the highly viscous cermet coatings

  longitudinal direction of the current inputs and does not

  come, next to the cermets, on the exposed parts

  current inputs. However, this could also

  should be avoided because the cermet coatings

  feel such a length that quartz glass can not

  not reach the discovered parts of the cou-

rant.

  On the other hand, in lamps in accordance with the

  vention, a rib is applied to prevent the

  quartz glass does not repel the intermediate glass,

  It is much less viscous, and does not enter the place of the intermediate glass in contact with an exposed part of the current inlet in question. So, in the lamps

  according to the invention, an intermediate glass coating

  longer length does not constitute alter-

  native for the application of a rib.

  The lamps according to the invention therefore have a structure, which is much simpler and more general e-t that lends itself to easy realization. The ribs applied above the current inputs

exert another effect.

  The description below, with reference to

  drawings, all given as a non-limitative example

  tative will make clear how the invention can be realized.

  Figure 1 shows a longitudinal section

  of a discharge lamp in mercury vapor at

high pressure.

  Figure 2 shows a section along the

  II-II plane of the lamp according to Figure 1.

  Figure 3 shows a side view of a

  halogen incandescent lamp with a single pinch.

  FIG. 4 is a cross-section of the nip of the lamp according to FIG. 3, according to the plane

IV-IV.

  Figure 5 shows a side view of a

  halogen incandescent lamp with two pinches.

  FIG. 6 is a section along the plane VI-

VI of the lamp according to Figure 5.

  In Figure 1, the quartz glass bulb 1 has flattened pinches 2 and 3. The pinch

  2 is crossed by a current input 4 around the-

  the nip 2 has the same geometry as the nip 3 around a current inlet 5. Over part of its length, the current inlet 5 is provided with a coating of an intermediate glass 6 having the composition b of previous table, coating that is sealed at the entrance 5. The quartz glass of the pinch

  3 is sealed between the ends of the coating 6.

  The current inlet 5, which is made of tungsten and has a diameter of 800 μm, is provided at its end 7 with tungsten windings 8 intended to constitute a main electrode. Next to the current inlet 5, a tungsten wire 10 provided with a coating 9 made

  with the same intermediate glass, is pinched and its

  It is an auxiliary electrode.

  FIG. 2 clearly illustrates the shape of the flattened nip 3. The nip 3 has small lateral faces 12 and 13 and large lateral faces

  14 and 15. On these latter faces are provided

  16, 17, respectively, which are each located above the entrance of court 5 and its coating

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  6 and extend over the entire length of the pin-

  CEE. Thus ribs 18, 19 respectively are provided above the current inlet 10 and

its coating 9.

  In Fig. 3, molybdenum current inlets 32 and 33, respectively, 600 μm in diameter, are sealed into the flattened pinch 30 of the quartz-31 glass bulb. The yarns are provided with an intermediate glass coating 34 and 35 having the composition d of the table. The current inputs 32 and 33 support a tungsten filament 46. FIG. 4 illustrates the presence of ribs 38, 39 and 40, 41 respectively above each of the current inputs 32, 33 respectively on the larger ones.

  side faces 36, 37 of the nip. These ribs extend

  tooth over the entire length of the pinched portion of the entrances

  32 and 33. The lamp shown can be used

in projection.

  In Figure 5, the quartz glass bulb has flattened nips 51 and 52 of similar geometry. In the nip 52 is inserted a tungsten current inlet 53, with a diameter of 700 μm, to which a coating 54 is applied by sealing,

  presenting the composition a of the table. Between the

  of the coating 54, the pinch glass 52 is sealed

  the coating audit. At its end located in the ampu-

  the 50, the current input has several turns in

  tungsten 5, which are referred to in filament 56. The lamp

  eg can be used for projectors.

  FIG. 6 shows the ribs 59 and 60, which are provided above the current inlet 53 and its coating 54 on the large lateral faces 57 and

  58 of the pinch 52, and which extend over the entire length of

  the pinch portion of the current input 53.

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Claims (3)

  1.- Electric lamp comprising a quartz glass bulb, (1), which is provided with current inputs (4, 5,) connected to an electrical element disposed in the bulb, while hermetically traversing the wall of said ampoules   the, and having, over a part of their length, a coating-   (6, 9) of an intermediate glass, between the ends of which the wall of the bulb is welded to said coating, characterized in that the bulb has a flattened nip (2, 3) into which is inserted at least one inlet current (4, 5, 10) and having, at each of these two large lateral faces (14, 15), for each current input inserted in the nip, a rib (16, 17, 18, 19) extending over the wire in question over the entire   length of the pinched part of the latter.   2. Lamp according to claim 1, characterized in that in a nip (3) are inserted at least two current inputs (5, 10).   3.- Electric lamp according to any one of the   1 or 2, characterized in that in the range of   temperature between 30 and 800WC, the intermediate glass   has an expansion coefficient of between -7 -1 ll and17 x 1 K