DE1764332B1 - METHOD OF GETTERING ELECTRIC LIGHT BULBS - Google Patents

Description

grind that in uniform form on the glow pentanitride in the mixture given above in wire helix can be applied. elemental white phosphorus and nitrogen decomposed

The slurry is applied in the conventional way and at the same time a small amount of oxygen to the filament filament of the lamps: this is released when the antimony decomposes - for example, the filament that is formed on the usual 5 tetraoxyds eventually becomes the lower anti -Lead wires attached, which- montrioxyd through the foot. The oxygen and the phosphorus make up the incandescent lamp to be worn, immersed. The P ₂ O ₈ , known as an excellent water getter, incandescent bulbs have a helical or double shape. However, the phosphorus pentanitride can also be used, such as coiled tungsten filament. The amount to be applied, already mentioned above, solely as getter material, can then be used past a heated strip. ·

led to an evaporation of the amyl amorphous phosphorus nitride is used as getter material

to cause acetate carrier material. The lamp- not suitable. It is assumed that the amorphous base with the getter material is then broken down with the material to form gaseous PN without the glass envelope surrounding the incandescent lamp combining in the usual substantial amounts of elemental phosphorus. The lamp will then be formed by a 15 nitrogen. The pure crystalline P ₈ N ₅ pipeline that is evacuated with the interior of the piston is a very stable connection that connects its identity. This is then maintained with% until the entire crystal is filled with an inert gas while hot and the pipeline is disconnected enough to melt directly into the whiter elements. The gas filling can decompose from an inert phosphorus and nitrogen.
Gas, for example nitrogen, argon, krypton or 20 The amount of phosphorus pentanitride used consist of xenon or mixtures thereof. Normally, every incandescent lamp is not particularly critical and the wise argon is used, which is approximately 2 to depending on the size and wattage of the lamp. It contains 12 percent by volume of nitrogen at an approximately atmo- can be regulated, for example, by the amount of spherical pressure it contains. The lamp envelope may have solid parts per unit volume of substrate, then fitted with a conventional base 35. As the slurry becomes thick, there will be more that has end contacts to which the supply solid parts are picked up by the filament. When connection wires are connected. The filament is conventional red phosphorus is used, which is then heated by applying a suitable voltage to the amount used, since the end contacts of the base are applied to the bulb to give the finished incandescent lamp a brown color. To heat the filament to a temperature that reaches from the other side the white or phosphorus to evaporate the phosphorus pentanitride pentanitride getter material can be limited if and in the elementary constituents phosphorus and nitrogen - a white cloudiness appears on the lamp bulb decompose. The white phosphorus is extreme. If more is used in the slurry, then it is reactive and quickly removes what is left - all that is observed is a browning of the lamp, there is oxygen and water vapor in the lamp - 35 But even in such cases the amount of bulbs has an effect. of the getter material is not disadvantageous, since the white

In a very humid weather, experiments were carried out on the veil and the brown color produced by the verd in which partly pure crystalline turn of larger amounts of phosphorus pentanitride Phosphorus pentanitride used as a getter material tend to disappear when the and for comparison only red phosphorus than 40 lamps burn, while the brownish effect is on Getter material. With the lamps, the red phosphorus the conventional lamps with red phosphorus contained, 90 to 100% of the leak detector continued to reject during use of the "lamp, while with the incandescent lamps, the phos- strengthens. This causes light absorption, phosphorus pentanitride contained less than 1% rejected and this has an adverse effect on the exterior of the became. Some of these rejected lamps run out of 45 lamps. Definitely can be a larger amount sat fine cracks through which air can penetrate. on crystalline phosphorus pentanitride can be used These lamps belong to the normal production as with the use of conventional red failure. Phosphorus.

Similar results are obtained with lamps, Incandescent wire evaporation, i. H. operating

in which an oxidizing agent is added to the crystalline 50 of the filament as the voltage increases, phosphorus pentanitride. A wide variety of oxidizing agents can be used over short periods of time for the purpose of evaporation of the getter material and for recrystallization of the wolf, provided that their degradation does not yield any substances. With respect to burnouts when using wise, oxidized metal compounds of phosphorus pentanitride are used than when using group V of the Periodic Table of the Elements lamps that use red phosphorus as getter material, which decompose and hold when heated. Lamps in which filament vaporization provides oxygen. Particularly suitable are both disadvantageous runs and a getter material, for example Sb ₂ O ₄ and BiPO ₄ . containing red phosphorus can cause arcing

A particularly advantageous getter mix consisted of 60 and burnouts. These disadvantages arise from 4 g of pure crystalline P ₃ N ₅ , 2 g of Sb ₂ O ₄ and none if the incandescent lamps contain phosphorus pentanitride sufficient amount of amyl acetate to 400 ml of the getter material.

Prepare getter slurry. With such a mass spectrometer analysis, annealing

Incandescent lamps provided with getter material gave good lamps, and P ₃ N ₅ results as getter material. Corresponding incandescent lamps with a 65 or red phosphor contained or, in the case of lamps, getter material, which consisted only of red phosphorus, which did not contain any getter material. They didn't turn out to be that beneficial. results obtained are in the present

It is believed that the phosphorus table given is:

Mass spectrometer analysis (micron liter)

No getter Red phosphorus P ₃ N ₅ CO ₂ 0.09
traces
0.12
6.2
0.42 0.03
0.20
7.0
1.3 H ₂ O CH ₄ CC H ₂ 0.02

The blank spaces mean that none of the specified materials was detected.

Photomicrographs of coils from 60 watt lamps made from the same tungsten wire showed no grain difference between the non-gettered coils and the P ₃ N ₅ gettered coils after filament evaporation,

Test # 1 P ₃ N ₅ red phosphorus 759 Test # 2 P ₃ N ₅ red phosphorus 797 805 754 839 800 823 788 831 805 806 770 831 779 843 723 836 819 834 - 821 782 827 762 Average: Average: 823 832

while the coils gettered with red phosphorus had a different grain structure at the coil ends. After a burning time of 100 hours, no differences were found between the three test sets. These experiments show that a more advantageous microstructure of the recrystallized tungsten wires is obtained if P ₃ N _{6 is used} instead of red phosphorus. To the improved light output (in lumens)

ίο to point out incandescent lamps that are pure crystalline Phosphorus pentanitride have been gettered compared to incandescent lamps with red phosphorus or with incandescent lamps without getter material, lamps were operated in test vessels in which the lamps were at work at extremely high temperatures. The following table shows the lumen outputs of the Incandescent lamps after a burning time of about 150 hours specified.

Test # 3
Pistons matted inside P ₈ N ₅ redder
phosphorus Average: 809 763 Test # 4 P ₃ N ₅ red phosphorus 750 no
Getter 805 753 695 811 791 692 812 739 - 763 - 810 759 808 736 818 754 801 - 790 762 760 708 708 820 808 803 - 686 Average: 797

The empty spaces refer to lamps that were burned out before they could burn for Reached 150 hours.

A getter mix for vacuum lamps can consist of about 5 g P3N5, 55 g cryolite and 2 g red phosphorus exist. These are dissolved in methanol except for a slurry of 100 ml. By the amount of Methanol can add the desired weight of getter material deposited on the filament filament should be set.

The pure crystalline P ₃ N ₅ getter material is obviously far superior to red phosphorus for the following reasons: The phosphorus pentanitride is not influenced by the elevated temperatures used in lamp manufacture, it is inert and hydrolyses or does not react with the suspended support material , there is no fire hazard at the lamp factories, as it occurs with other dried getter materials, the number of rejections by a sensitive leak detector is very much reduced and this leads to significant economic savings; the P ₃ N ₅ has less of an effect on the crystalline structure of the tungsten wire and prevents the occasional problem of lamp burn-out as a result of faulty filament evaporation. Since white phosphorus is presumably one of the degradation products, it can be concluded from this that a longer getter action takes place with the remaining substances, namely during the entire service life of the lamp. The white phosphorus is more effective as a getter material at significantly lower temperatures than the red phosphorus.

The pure crystalline phosphorus pentanitride is far from the red phosphorus in the manufacturing process superior, especially when the red phosphorus is spiraling out of control, such as when the Preheating, baking temperatures, atmospheric humidity in particular, and similar factors become extremely variable and out of control, so the red phosphorus for example is heavily oxidized or even evaporated from the filament before the lamp is sealed or melted off is. The red phosphorus can also be hydrolyzed by the high humidity or it reacts with the suspended carrier material if it is used for several days, for example over a weekend, leaves standing. Under such conditions it is not possible to get an even with the red phosphorus Product to receive. However, if pure crystalline phosphorus pentanitride is used, then one obtains uniform light bulbs of high quality and stability.

Claims (7)

1 2 is suspended. If the aryl acetate has not completely evaporated during this time, it is completely removed by the heat of the melting process. 1. Process for gettering electrical incandescent lamps The lamp is then illuminated through a pipe vent, in which by means of a pumped in an airtight 5, which is connected to the interior of the lamp envelope closed lamp bulb arranged is connected. The pipeline is then disconnected from the glow wire a phosphorus melt serving as a getter. Nitrogen compound is thermally decomposed, during the melting and evacuation characterized in that the lamp bulb is through as the lamp moves Getter pure crystalline phosphorus pentanitride heated to a temperature in the range of about is turned. 200 to 600 ⁰ C brought. The temperature depends 2. The method according to claim 1, characterized in that the glass composition of the lamp bulb indicates that the crystalline phosphorus should be adsorbed on the surface and thereby Pentanitride cryolite is added. absorbed gases are removed. Based on these 3. The method according to claim 2, characterized in that the getter made of red phosphorus is characterized by the fact that the mixture of crystalline filament is ^{oxidized and evaporated at a temperature of about 200 °} C. phosphorus pentanitride and cryolite. This is where the agent is added. Temperature of the filament about at or above 4. The method according to claim 1, characterized in that the temperature is during melting. By indicates that the crystalline phosphorus losses of active getter material can be subpentanitride an oxidizing agent is added. differ in service life and handling 5. The method according to claim 4, characterized in that the electric incandescent lamps are produced. distinguishes that the oxidizing agent is a metal which can furthermore be different atmospheric Group V of the Periodic Table of the Elements Moisture conditions significantly affect the quality which is degraded after heating and has an effect on the lamp, due to the oxygen supplies. deterioration of red phosphorus and its inability to 6. The method according to claim 4, characterized in that the increased water vapor content in the lamp is characterized in that the oxidizing agent is Sb ₂ O ₄ . to remove, caused by the presence of over- 7. The method according to claim 4, characterized in that the water vapor is on the lamp parts and that the oxidizing agent is BiPO ₄ . 3 ° arises on the machine parts. In the German patent 833 080, antimony trioxide is specified as the alkali bond of the getter. The invention is based on the object that To improve the aforementioned method for gettering electrical incandescent lamps. This object is achieved in that as a getter The invention relates to a method for gettering pure crystalline phosphorus pentanitride is used, electric incandescent lamps, in which by means of a surprisingly could namely be found a hermetically sealed bulb be reasonable that pure crystalline Phosphorpentanitrid arranged filament serving as a getter phosphorus 40 (P ₃ N _5), a particularly advantageous getter phor-nitrogen compound is thermally decomposed. shows. It is particularly resistant to adverse reactions with water vapor and other 1,991,510. atmospheric gases at temperatures that It is thus known that remaining gases in the melting or sealing of the lamp electric light bulbs cleaned by means of phosphorus 45 the evacuation procedure can be used. That or can be removed. Usually phosphorus pentanitride can then be used thermally the phosphor is introduced into the lamp in such a way that it is decomposed, the components phosphor and stick evaporated or sublimated and with the inside fabric presumably by heating to higher temperatures Lamp bulb remaining gas reacts and temperatures, such as approximately 1000 ° C. this removed when the filament for annealing 50 when the phosphorus pentanitride thermally decomposes is brought. In the case of gas-filled lamps, the phosphor produced in this way is nascent it is beneficial to use red phosphorus alone. and extremely active. The white phosphorus component With vacuum lamps, the normally lower one is extremely effective and removes oxygen quickly Have wattages, such as 25 watts or and water vapor and some of their precipitation less, the red phosphorus usually gets with the inner lamp parts including the bulb Material such as cryolite mixed walls so that the cleaning or removal (U.S. Pat 1 989 790). effect throughout the life of the lamp In the case of incandescent lamps, the getter mixing is stopped. usually attached directly to the filament, Crystalline Phosphorus Pentanitride (P ₃ N ₅ ) is a which is usually made of a coiled tungsten 60 commercial product. It is preferably made up of the wire. The getter mixture is usually produced by reaction of P ₂ S ₅ with ammonia. This is well known as a slurry or suspension of the red process. Phosphorus in a suitable vaporizable carrier- It is, for example, a slurry or substance, such as aryl acetate, produced. The suspension made, which consists of pure crystalline getter mixture, is made by dipping or loading 65 P ₃ N ₅ in amyl acetate. 1 g of P ₃ N ₅ is applied by spraying 100 ml onto the glow wire. The aryl amyl acetate mixed in. The powdery P ₃ N ₅ acetate is evaporated by breaking the glow wire in front of it, mixing it with the carrier substance, fixing it in the lamp bulb, warm air and then preferably converting it into very fine particles.