US2099874A

US2099874A - Method of evacuating vessels, more particularly lamps

Info

Publication number: US2099874A
Application number: US729908A
Authority: US
Inventors: Trenzen Carl
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-12-04
Filing date: 1934-06-09
Publication date: 1937-11-23
Anticipated expiration: 1954-11-23
Also published as: GB439243A; BE406626A; DE632578C; NL40433C

Description

Patented Nov. 23, 1937 PATENT OFFICE METHOD OF EVACUATING VESSELS, MORE PARTICULABLYIAMPS Carl Trenzen, Venlo, Netherlands No Drawing. Application June 9, 1934, Serial No. 729,908. In Switzerland December 4, 1933 '1 Claims.

This invention relates to a method of evacuating vessels, and more particularly the bulbs of lamps In the evacuation of vessels, particularly those 5 in which bodies are raised to a very high temperature, as occurs, for example, in connection with the bulbs of lamps, the evacuation requires to be extended as far as possible in order to obtain a poor transmission of the heat tothe outer wall of the vessel. Together with the air it is also necessary to expel every trace of steam, as the latter will exert a very destructive efi'ect on the lamp. Despite the care taken it has not been possible up to now to eliminate every trace of v residual gas with the ordinary mechanical means available. For this reason there has been adopted the so-called getter process, consisting in the introduction of means which evaporate when the lamp is switched on and bind chemically with 0 the residual traces of gas (Malignani process). For the getter process there are employed special phosphorous compounds.

In this process the traces of gas, although bound, remain in the bulb, and if conditions are 5 favorable-the P205 formed may again be decomposed and thus again liberate the gas. This action is liable to shorten the life of the lamp.

In the process according to the invention there is employed for the evacuation of vessels, and

0 more particularly lamp bulbs, a metal carbonyl, which is introduced into the partially evacuated vessel or bulb. If the vessel is afterwards heated the carbonyl becomes decomposed. CO is liberated, and this CO, which in contradistinction to 5 ordinary very inert CO is an extremely active gas,

combines with the residual gases oxygen, nitrogen and hydrogen.

At a suitable temperature the gases still present in the'filament are also bound, so that the filament may be subjected to a higher load without eilect on its durability. The evacuation is afterwards continued. Upon the decomposition the metal may be allowed to remain in the gaseous form dependent on the temperature employed,

; so that the same is also included by the vacuum, or it may be deposited on to a particularly heated part of the vessel.

In the case of lamp bulbs precautions will be taken that this deposit is produced only at a point having no detrimental efle'ct, or the heating will be so performed that the metal is deposited in the form of a finely distributed reflector in such a manner that it reflects the light of the filament towards the side where the same is required.

In carrying the invention into efl'ect the process such as nickel carbonyl Ni(C0)4, molybdenum 5 1 carbonyl M0(CO )2 or fen'ocarbonyl. The lamp is afterwards subjected to the decomposing temperature at the pressure prevailing. The metal carbonyl is decomposed, and the liberated metal produces at ,the point of heating a bright reflector. The very active CO combines spontaneously with the residual traces of oxygen, nitrogen and hydrogen in the interior of the bulb and the filament, which gases may be much more readily expelled than if the same adhere singly to the glass wall. Whereas, therefore, in the known getter processes, 1 the gases remain in bound form in the lamp, and may always exert a detrimental effect on the life of the lamp, the same in the case of the invention are expelled from the lamp. 2 The metallic reflector remaining in the'bulb nevertheless also acts as getter, since owing to its fine distribution it is able to absorb and render harmless the, traces of injurious gas emerging later from the filament or the edge of the glass. By suitably heating the bulb it is also possibleto apply the metallic reflector to points where the same is useful, 1. e., may be utilized for reflecting the light in a certain direction.

In place of one single metal carbonyl it is also possible to employ a mixture of diflerent carbonyls.

In the above example reference has, merely been made to the evacuation 01 a lamp bulb. It is obvious. however, that this method may be employed both for evacuated as well as gas-filled lamps It has been found that by the simultaneous use of phosphorous as a getter in conjunction with a metal carbonyl the eflect above referred to is obo tained in the most simple and reliable fashion, socalled phosphorous solution being injected or sprayedon for example together with a metal carbonyl. Molybdenum carbonyl and tungsten carbonyl have been found very effective as addition to phosphorous solution. Embodiment in the form of a double spiral is also advisable, as the surfacefor reception of the getter is formed accordingly.

What I claim as new and desire to secure by Letters Patent is: I

1. Amethodof evacuating vessels,- and more particularly lamp bulbs, which consists in partial- 1y evacuating the vessel, then introducing at least one metal carbonyl, and thereupon heating u in claim' 1, in which the temperature employed for decomposing the metal carbonyl isrsuch that the metal remains, in a gaseous state and is removed upon completing the evacuation.

3. A method of evacuating vessels, and more particularly lamp bulbs, which consists in partially evacuating the vessel, then introducin nickel carbonyl into the said vessel, heating the said vessel to cause decomposition .of the said nickel carbonyl, so that the air and traces of gas combine with the liberated CO, and then completing the evacuation of the said-vesel.

4. A method of evacuating vessels, and more particularly lamp bulbs, which consists in partially evacuating the vessel, then introducing molybdenum carbonyl into the said'vessel, heating the said vessel to cause decomposition of the said molybdenum carbonyl, so that the air and traces of gas combine with the liberated C0, and then completing the evacuation of the said vessel.

5 A method of evacuating vessels, and more particularly lamp bulbs, which consists in partially evacuating the vessel, then introducing ferrocarbonyl into the said vessel, heating the said vessel to cause decomposition of the said ferrocarbonyl, so that the air and traces of gas combine with the liberated CO, and then completing the evacuation of the said vessel.

6. A method of evacuating vessels, and more particularly lamp bulbs, as claimed in claim 1, in which a mixture of carbonyls and phosphorous solution is introduced into the said vessel.

7. A method of evacuating vessels, and more particularly lamp bulbs, which consists in partially evacuating the vessel, then introducing a carbonyl of a metal of the group consisting of nickel, molybdenum, iron, tungsten, into the said vessel, heating the said vessel to cause decomposition of the said carbonyl, so that the air and traces of gas combine with the liberated CO, and then completing the evacuation of the said vessel.

' CARL TRENZEN.