US3586896A

US3586896A - Incandescent lamps having a transport gas comprising a bromine and a chlorine hydrocarbon compound

Info

Publication number: US3586896A
Application number: US838781A
Authority: US
Inventors: Riksterus Auguste Johan Meijer; Germin Remi T Jampens
Original assignee: US Philips Corp
Current assignee: US Philips Corp
Priority date: 1966-10-08
Filing date: 1969-07-03
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22
Also published as: GB1151318A; SE338366B; DE1589266B2; ES345811A1; DK129678C; DK129678B; CH519784A; NO121221B; JPS5233432B1; NL6614205A; BE704814A; US3484146A; DE1589266A1

Abstract

A regenerative cycle electric incandescent lamp having a tungsten filament and containing a transport gas essentially consisting of an inert gas and a bromine and chlorine hydrocarbon compound.

Description

mite States Patent [72] Inventors Riksterus Auguste Johannes Maria Meijer;

Appl. No. Filed Patented Assignee Priority Germin Remi TJampens, hoth o1 Emmasingel, Eindhoven, Netherlands 838,781

July 3, 1969 Division 01 Ser. No. 672.619. Oct. 3. 1967. Pat. No. 3.484.146.

June 22, 1971 11.5. Phillips Corporation New York, NY.

Oct. 8, 1966 Netherlands INCANDESCENT LAMPS HAVING A TRANSPORT GAS COMPRISING A BROMINE AND A CHLORINE HYDROCARBON COMPOUND 4 Claims, 2 Drawing Figs.

[52] US. Cl 313/174, 313/176, 313/222, 313/223 [51] Int. Cl H0lk1/50 [50] Field of Search 313/174, 176, 179, 185, 222, 223

[56] References Cited UNITED STATES PATENTS 1,925,857 9/1933 Van Liempt 313/223 X 3,418,512 12/1968 TJampens eta]. 313/222X Primary Examiner-Raymond F. l-lossfeld Attorney-Frank R. Trifari ABSTRACT: A regenerative cycle electric incandescent lamp having a tungsten filament and containing a transport gas essentially consisting of an inert gas and a bromine and chlorine hydrocarbon compound.

PATENTEH'JUN22 mm FIG] FIG.2

INVENTOR5. RIKSTERUS A.J.M. MEIJER GERMIN R. T'JAMPENS BY i '6 I? AGENT llNCANDESCENT LAMPS HAVING A TRANSPORT GAS COMPRISING A BROMINE AND A CHLORINE HYDROCARBON COMPOUND This is a division of applicants copending patent application, Ser. No. 672,619, filed Oct. 3, 1967, now US. Pat. No. 3,484,146.

A method of manufacturing incandescent lamps having a tungsten filament in which during the final stage of manufacture the lamp is evacuated and filled with a mixture of an inert gas and bromine-chlorine hydrocarbons.

The invention relates to a method of manufacturing an incandescent lamp having a filament of tungsten and a brominecontaining transport gas in which during the last manufacturing steps the lamp is evacuated, is then connected to a storage cylinder which contains an inert gas and a bromine-hydrocarbon compound, is then filled with the gas mixture to the desired pressure and subsequently closed, usually by sealing an exhaust tube which up to that instant formed one assembly with the bulb.

The bulbs of incandescent lamps obtained in this manner remain bright till the end of the lifetime of the tungsten coil providedit is ensured that the wall of the bulb during operation of the lamp everywhere reaches a temperature at which the tungsten-bromine compounds formed in the lamp cannot condense. After some time in operation there prevails a dynamic equilibrium in the lamp in which as a result of thermal decomposition of the tungsten compound in the proximity of the coil the amounts of deposited tungsten and evaporated tungsten are the same.

Suitable bromine-hydrocarbons are, for example, tribrornomethane (CHBr monobromomethane (CH Br) but in particular the dibromomethane (CI-I,Br,) Other brominehydrocarbon compounds also, if required together with a suitable amount of hydrogen, may be used.

Dibromomethane, which is preferably used has a rather low vapor pressure at room temperature. This is a drawback in this particular way of lamp manufacturing. At 25 C. this pressure is only approximately 40 Torr.

For practical reasons the partial pressure of the dibromomethane in the storage cylinders may not be equal to said vapor pressure. In fact, it should be prevented that as a result of a decrease in temperature condensation of the dibromomethane occurs in the storage cylinders. A decrease in temperature may occur, for example, at night or during the weekend. Condensation results in unfavorable variation of the composition of the gas mixture in the storage cylinder. After an increase in temperature it takes ample time until a homogeneous gas mixture is present again in a cylinder in which condensation has occurred, For that reason the storage cylinders are normally filled with dibromomethane to a partial pressure of approximately 28 Torr which corresponds to the pressure of said compound at approximately 16 C.

in practice this means, that, taking losses into account, for example approximately 10.000 lamps with a volume of approximately 0.25 cm. can be filled to a pressure of approximately 5 atmospheres from a cylinder having a capacity of 8 l. which is filled with a gas mixture of krypton l. dibromomethane to a pressure of 8.2 atmosphere.

in this case the storage cylinder may be used until the pressure therein has decreased to approximately 1.2 atmosphere. The cylinder is then emptied, so many litres of krypton of 1.2 atmosphere being lost as the water capacity of the cylinder is. it is not possible to replenish a cylinder in which a pressure of 1.2 atmosphere prevails within a reasonable time with a mix ture of krypton and CH,Br 2 because the vapor pressure of the latter is too low for that purpose. The operation of filling the lamps must thus be interrupted for exchanging the storage cylinders in this example after every approximately 10.000 lamps.

it is the object of the invention to mitigate these drawbacks and a particular object of the invention is to enable the filling of more lamps using one storage cylinder, to restrict the loss of rare gas, and to reduce the number of times a new gas mixture has to be prepared and stored in storage cylinders.

According to the invention this may be achieved by using a gas mixture in which bromine and chlorine are present in the form of hydrocarbon compounds.

The greatest improvement is reached if bromochloromethane (CH BrCl) is used. In comparable circumstances the admissible partial pressure of this compound in the storage cylinders is approximately Torr. This means that with one storage cylinder filled with bromochloromethane to said pressure, if also the partial pressure of the inert gas is adapted accordingly, approximately three times as many lamps can be filled with the same halogen percentage as is possible with bromomethane in the manner described.

in this manner the loss of rare gas decreases to approximately one third while the labour time for'exchanging, filling and the like can be reduces to one third.

However, a considerable saving is also obtained already if the gas mixture contains both dibromomethane and dichloromethane to the same partial pressure. From one storage cylinder approximately two times as many lamps can now be filled, while the labour time for certain parts of the manufacturing process can approximately be halved, too.

The invention is based on the use of the property that the mixed bromine-chlorine hydrocarbon compounds and the chlorine hydrocarbon compounds generally have a higher volatility than the corresponding bromine hydrocarbon compounds.

It was found that in lamps which contain a bromine containing transport gas, for example, half of the bromine may be replaced by chlorine; with this composition in which the ratio bromine-chlorine is H additional advantages are obtained. The ratio hydrogen to halogen preferably is likewise lzi in gramatoms.

It was found that when using such a ratio the total quantity of halogen (bromine together with chlorine) in gramatoms in the lamps may be smaller than in the case of bromine alone, with an equal lifetime and luminous efiiciency of the lamps.

Of course, the method according to the invention is not restricted to the use of brominechlorine methane (CH CIBr) or mixtures of CH 2 and CH CI For example, also mixtures of CHBr and CHCl, may be used, if required by adding hydrogen to the gas mixture. Mixtures of CHBr CI and CHBrCl or higher hydrohaiogenic compounds or higher mixed halogen hydrocarbon compounds may also be used.

The invention will now be described in greater detail with' reference to the ensuing specific examples in which reference is made to the accompanying drawing the FIG. 1 of which diagrammatically shows the filling (with transport gas) of the lamps according to the invention and FIG. 2 shows a filling cock.

FIG. 1 diagrammatically shows a device for filling incandescent lamps with gas. The device comprises in principle a storage cylinder 1 and

pipes

2, 6 and 7. In the pipe 2 a reduction valve 3 and a filling cock-4 are arranged. The pipe 2 communicates with a pipe 6 through a three-way valve 5 which pipe 6 serves for transporting the filling gas to the incandescent lamps to be filled and a pipe 7 which is connected to a vacuum pump which is not shown and which serves for evacuating the system. in a practical example the pressure in the storage cylinder 1 having a capacity of 8 litres initially was 24.6 atmosphere. The gas mixture consisted of krypton and 0.45 percent by volume of CH BrCl. By means of the reduction valve 3 it is ensured that the pressure between the reduction valve and the filling cock 4 remains constantly 1.2 l atmosphere as long as the pressure in the storage cylinder has not [alien to said pressure. FIG. 2 diagrammatically shows a cross section of a filling cock 4. The filling cock consists in principle 0! a spindle 8 in which a hollow space 9, capacity 2 cm.", is present the spindle being rotatable in a seating 8 a provided with two

apertures

10 and 11 which communicate with the pipes 2. The filling cock further comprises a pipe 12 which communicates with a vacuum pump. As a result of this the spindle 8 cannot be released from the seating 8 a during filling.

By means of this cock 4 a dosed quantity of filling gas can be introduced in the rest of the system. During filling the incandescent lamp the procedure is as follows (see also Fig. 2). The exhaust tube 13 of the incandescent lamp 16 is made to communicate with the pipe 6. The filling system from the filling cock 4 up to and including the incandescent lamp are evacuated until the pressure is approximately l Torr. The pipe 7 is then closed by means of the three-way cock 5. The filling cock 4 is now rotated so that the space 9 communicates with the evacuated part of the system. Since the lamp 16 (capacity approximately 0.25 cm.) is to be filled to a pressure of approximately 5 atmosphere at room temperature, said lamp is placed in a vessel containing liquid air 14. After a few seconds the exhaust tube is sealed immediately over the surface of the liquid air 14 in the vessel 15 by means of a gas flame (not shown).

The lamp is now ready for use. 30.000 lamps can be filled from one storage cylinder, taking the losses into account. At a pressure of 8.2 atmosphere in the cylinder, as is maximally possible when using CH B this number is approximately 10.000 lamps.

It has been found that in incandescent lamps having a gas filling of approximately 1 atmosphere consisting of gas mixture of, for example, argon and CH,,Br or CH,BrCl, the CH,Br, may be replaced by a smaller quantity of cH BrCl.

In practical example, a photolamp of 1000 Watt at 225 Volt with a color temperature of 3400 K. the gas filling consisting of 700 Torr Ar 8 percent by volume of N,+l percent by volume of CH,Br, may be replaced by 700 Torr Ar 8 percent by volume of N,+0.5 percent of CH BrCl. A lower partial halogen pressure built up from chlorine and bromine in the ratio 1:1 thus is sufficient to maintain the cycle while the luminous efficiency of the lamp of approximately 32Lm/w. and the lifetime of approximately 30 hours are at least maintained.

Another advantage of the method according to the invention is that certain types of lamps can only be manufactured as a result of this method.

So far it was not possible to manufacture long cylindrical high loaded lamps for operation in a vertical position with a bromine-or iodine-containing filling has and a high rare gas pressure. In this type of lamps gas separation occurred as a result of which the iodine or bromine concentration in the upper and lower part of the lamps differed strongly after burning for some time. This had for its result that the lamp began to blacken at one of its filament ends by a local deficiency of halogen while the other end of the filament was strongly attacked by an excess of atomic halogen. As a result of this lamps were obtained having one black end and a comparatively short lifetime.

It has now been found that in such lamps the tungsten halogen cycle can be maintained by chlorine and bromine together without blackening of the bulb and attack of the filament occuring. The good operation of the lamp burning in a vertical position is ensured in spite of the demixing of the gas filling of the lamp. However, the demixing is such that the tungsten-halogen cycle on one side of the lamp mainly occurs between tungsten and bromine and on the other side of the lamp space mainly between tungsten and chlorine.

In the center of the lamp both cycles occur.

What we claim is:

l. A regenerative cycle incandescent electric lamp comprising an envelope, a tungsten filament, the distance from the filament body to the wall of the envelope being so proportioned that the temperature of the wall of the envelope throughout the surface everywhere reaches a temperature at which tungsten-bromine chlorine compounds formed cannot condense, and a mixture of brominated and chlorinated hydrocarbons and an inert has fillin%said envelope 2. A regenerative cycle mcan escent electric lamp as claimed in claim 1 wherein the brominated and chlorinated hydrocarbons essentially consist of bromine and chlorine methane compounds.

3. A regnenerative cycle incandescent electric lamp as claimed in claim 1 wherein the brominated and chlorinated hydrocarbons essentially consist of bromochloromethane (Cfl BrCl).

4. A regenerative cycle incandescent electric lamp as claimed in claim 1 wherein the brominated and chlorinated hydrocarbons essentially consist of a further mixture of dibromomethane (CH Br and dichloromethane (CH Cl UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 353 .395 Dated June 22 1q7 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

q Column 2, line 35, change "11" to --l:l--

line 44, change "CI-1 2" to -CH Br Column 3, line 1 change "10 to --l0" Claim 1, line 30, change "has" to -gas- Siszned and sealed this 21 st day of December 1 971 (SEAL) fittest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissionerof Patents

Claims

2. A regenerative cycle incandescent electric lamp as claimed in claim 1 wherein the brominated and chlorinated hydrocarbons essentially consist of bromine and chlorine methane compounds.
3. A regnenerative cycle incandescent electric lamp as claimed in claim 1 wherein the brominated and chlorinated hydrocarbons essentially consist of bromochloromethane (CH2BrC1).
4. A regenerative cycle incandescent electric lamp as claimed in claim 1 wherein the brominated and chlorinated hydrocarbons essentially consist of a further mixture of dibromomethane (CH2Br2) and dichloromethane (CH2C12).