DE2430695A1 - LAMP WITH DIFFERENTIAL POWER OUTPUT - Google Patents

Description

The present invention relates generally to incandescent electric lamps. More specifically, it relates to such electric incandescent lamps with differential power output in which hydrogen and chlorine are available for a regenerative cycle to run, with which the bulb wall is kept free from tungsten blackening.

Eliminating the blackening of the bulb wall is in the lamp industry been a task for years. Tungsten evaporated from the filament is deposited on the bulb wall and thereby reduces the fourth of the lumen / watt output during the service life the lamp. .

It has been found that halogens such as iodine (in US Pat. No. 2,883,571) and bromine and chlorine (in US Pat. No. 3,418,512) interact with the tungsten on the bulb wall with the formation of compounds

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how tungsten iodide and tungsten bromide combine that on the thread dissociate into free halogen and tungsten, the tungsten being deposited on the filament again. This kind of Tungsten-halogen cycle or reaction occurs at certain bulb wall temperatures on. If the halogen gas is a more reactive one, such as chlorine, then this is the bulb wall temperature required for the reaction less than when using iodine. It was also believed that the more reactive gas would corrode lamp parts would, and therefore hydrogen should be added to the fill gas to combine with the free halogens.

Many new and different types of lamps have been tried to achieve this Apply tungsten-halogen cycle. One such application is a lamp with differential power output, such as those used in photoprographic Machines used to evenly illuminate photocopy paper. These special lamps are in the U.S. Patent 3,295,007 is described in more detail.

Because the bulb wall temperature in certain types of reprographic lamps is relatively low in certain places and because such a lamp is always turned on and off, it is difficult to initiate and maintain a tungsten-halogen cycle to keep the bulb wall clean.

Trials with iodine have been made in some differential power output lamps and it has been found to be relative inactive to prevent the bulb wall blackening over the illuminated area, which was caused by vaporized precipitation Tungsten and the formation of tungsten iodide precipitates in the colder, unlit areas of the bulb wall. Bromine has also been used on a trial basis, and although an improvement compared to iodine was found, precipitates still formed in the colder areas, which the light emission of the thread affected.

Chlorine and hydrogen are in lamps with differential power output has already been used, as described in DT-PS 1 9 ^ 8 481

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wrote. According to this PS, however, the ratio of hydrogen to chlorine always be greater than 1.25 and it can have a value have up to 2.50. It is believed that the regenerative Halogen cycle would not take place with these ratios, presumably because 'this amount of excess hydrogen is a large one Amount of chlorine binds to form HCl and leaves only an insufficient amount of chlorine. To act as a means for a regenerative Cycle to act. Other chlorine-halogen combinations, as claimed in US-PS 3,644,772, are because of the chlorine

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amount of 3 10 g atoms / ml flask volume is unsuitable, which is too small to successfully operate a lamp with differential power output, in which the .Windungen of the filament are pulled apart at intervals- (in English such a lamp is short as "pulled turn" lamp), in which the special duty cycle is to take place according to the present invention.

It has been found in the present invention that there is an improved regenerative lamp with differential power output obtained when chlorine and hydrogen are used as part of the purging gas used for such a lamp in such quantities that

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between 3.6 x 10 'and 5> 1 x 10' g-atoms of chlorine / ml flask volume and between 1.8 χ 10 and 4.0 χ 10 g-atoms hydrogen / ml Flask volumes are j where the ratio of hydrogen / chlorine has a value in the range of 0.352 and 1.11. The specified Chlorine and hydrogen levels are effective for lamps with duty cycles that have off times between 0 and 28 seconds.

The invention is explained in more detail below with reference to the drawing. Show in detail:

FIG. 1 shows a side view of the lamp according to the invention and

FIG. 2 shows an enlarged partial view in section of the lamp according to Figure 1.

In Figure 1, 10 is an incandescent lamp with differential power output denotes, which has a piston 11 made of translucent

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gem glass or quartz, a thread 12 for differential power output, Foils 13 and outer lines 14 includes. The foils are hermetically sealed in a pinch seal at each end of the lamp 15 sealed.

The lamp 10 is pumped out and filled with a filling gas, the small proportions of hydrogen, chlorine and inert gas, such as argon or Nitrogen. After the lamp has been filled, the pump-out nozzle is melted. The melted off remainder of the exhaust pipe is shown at 16.

Lamps with different ie Her power output according to the present Invention can have many types of filament configurations that have more light or radiant energy at the ends than in the middle of the lamp. In the lamp shown in FIG. 1, the thread 12 has filament parts 17 and extended ones in between Parts 18. Support devices 19 prevent the spiral parts 17 from sagging and thus support the extended parts 18. As shown in more detail in Figure 2, the extended parts 18 are only one or more drawn turns of the, what was previously a spiral part. Although a preferred embodiment is shown, other thread configurations can also be used with longer or shorter helical segments and longer or shorter ones drawn segments can be used in conjunction with the filling gas mixtures according to the present invention. The undressed Parts 18 only glow slightly when current is carried and generate a heat that is low compared to the coil parts 17.

In known lamps with differential power output was first Iodine is used to prevent the bulb blackening caused by tungsten deposits on the bulb wall. Since the The temperature required for the conversion of iodine and tungsten cannot be reached and maintained in certain types of lamps can, the area of the bulb wall 20 would blacken compared to the luminous filament part 17. This accumulation of tungsten would shorten the life of the lamp. The blackening in this type of iodine lamp is most prevalent in using lamps

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long off cycles.

Then the lamps were filled with bromine as necessary for the implementation The temperature required between bromine and tungsten is lower than that required for the reaction between iodine and tungsten. Though bromine lamps one; Improved over iodine lamps there are different yellow-red precipitates from which assumed will be made of tungsten oxybromide at the ends of the extended portions 18 as shown at 21. The yellow-red precipitations decrease with increasing distance from the ends of the extended part 18 to the center 22. The precipitates start again in the same beveled fashion when you look at the opposite end of the extended part 18 approaches. Any attempt to reduce the bromine content and thereby, the formation of tungsten oxybromide, leads to tungsten precipitates, which form opposite the helical part 17.

To obtain an efficient halogen regeneration cycle, Chlorine, which reacts with tungsten at lower temperatures than bromine and iodine, as well as hydrogen introduced into the lamp. Obviously because of the possible corrosive effect of chlorine on lamp parts, it was assumed that there was an excess of Hydrogen was required to combine with chlorine to form HCl. The ratio of hydrogen to chlorine in the known lamps was therefore larger than 1.25. However, it is believed that for the type of lamp where the filament is in the gaps Has solid parts, the regenerative cycle will not work with these ratios and the piston wall therefore would blacken.

After various tests it was found that the hydrogen / chlorine ratio should have a value of 1.11 or less, but at least one of 0.352 or more. Since the extended parts 18 generate some heat, it was found that more hydrogen should be used, more hydrogen compared to a lamp that has short-circuited segments. In addition, the corrosive effects of the free Chlorine on lamp parts is very delayed with these amounts of hydrogen.

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To determine the correct amount of chlorine and hydrogen to use in of the lamp of the present invention, the off time of the on-off duty cycle was found to be an essential factor. This is because the bulb wall of a lamp that is off for 25 seconds, for example, will have a lower temperature than that of a lamp that is only off for 5 seconds.

It was found that the amount of chlorine required for a lamp with an off time between 0 and 28 seconds

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is, between 3.6 χ 10 'and 5.1 x 10 g-atoms / ml flask volume lies. The amount of hydrogen can be in the range from 1.8 10 to 4.0 10 g-atoms / ml flask volume.

The lamp according to the invention is better than the known lamps, because no deposits form on the bulb wall opposite the luminous filament part 17, which is shown in FIG. 2 at 20. This is probably due to the fact that the bulb _{wall temperature at 20 is higher than about jsrty o} C. °

Although chlorine can be added to the lamp as an element or compound, the preferred form is carbon tetrachloride CCIi ₁ . In a special commercial embodiment of the

-7 lamp according to the invention it was found that 5.1 x 10 g-

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Atoms of chlorine / cm flask volume and 3.3 x 10 g atoms / cm flask volume effectively prevent blackening of the bulb wall and attack of chlorine on lamp parts. This particular lamp was operated with a duty cycle of 2 seconds on and 28 seconds off. In addition to these parameters, the lamp was filled to a pressure of 3.2 atmospheres and contained argon as an inert gas. This lamp was generally operated with 1000 watts and can be connected to a voltage of 180 or 230 volts.

Claims (6)

- 7 claims . [ 1./ Incandescent lamp with a regenerative halogen cycle, differential power output and a duty cycle whose off time is in the range from 0 to 28 seconds, the lamp having an elongated tubular bulb and a filament with extended parts that extend axially extends in the flask and with the ends of which current-supplying conductors are connected, which are hermetically sealed in the flask and the flask contains a filling of an inert filling gas, an amount of hydrogen and an amount of chlorine, thereby ■ geke η η I show η et that Chlorine in an amount of -7 -7 3.6 × 10 g atoms to 5.1 × 10 g atoms / ml flask volume and - 7-7 Hydrogen in an amount of 1.8 10 to 4.0 χ 10 g-atoms / ml Flask volumes are present and the hydrogen / chlorine ratio varies in the range of about 0.352 to 1.11. 2. Incandescent lamp according to claim 1, characterized - 7 shows that the amount of chlorine is 5.1 x 10 g atoms / ml flask volume, the hydrogen _{amount is 3 S} 3 x 10 g atoms / ml flask volume and the working cycle is 2 seconds on and 28 seconds off . 3. Incandescent lamp according to claim 1, characterized by dadur-ch that the chlorine in the lamp is added in the form of carbon tetrachloride. 4. Incandescent lamp according to claim 1, characterized that they have a duty cycle with an on-time of 2 seconds and an off-time of 28 seconds Has. 5. Incandescent lamp according to claim 1, characterized in that that it has a duty cycle of 2.5 seconds on-time and 3.5 seconds off-time. 409883/0423 6. Incandescent lamp according to claim I _3, characterized in that it has a working cycle with an on-time of 1.5 seconds and an off-time of 1 second. 4 0 9 8 8 3 - ^ - 0 4 2 3