iiililiili^ @ EuroPean Patent Office

^-S Office europeen des brevets (fi) Publication number: 0 422 047 B1

@ EUROPEAN PATENT SPECIFICATION

@ Date of publication of patent specification : @ Int. CI.6 : F21H 1/02 10.05.95 Bulletin 95/19

(2j) Application number : 89906887.8

(22) Date of filing : 24.05.89

(86) International application number : PCT/US89/02253

(87) International publication number : WO 89/12200 14.12.89 Gazette 89/29

(54) GAS MANTLE TECHNOLOGY.

(30) Priority : 06.06.88 US 203312 (73) Proprietor : White Consolidated Industries, Inc. 11770 Berea Road (43) Date of publication of application Cleveland Ohio 44111 (US) 17.04.91 Bulletin 91/16

@ Inventor : DIEDERICH, Walter, J. (45) Publication of the grant of the patent : 52 Church Street 10.05.95 Bulletin 95/19 West Newbury, MA 01985 (US)

@ Designated Contracting States : (74) Representative : Kirschner, Klaus Dieter, AT BE CH DE FR GB IT LI LU NL SE Dipl.-Phys. et al Patentanwalte Herrmann-Trentepohl, Kirschner, (56) References cited : Grosse, Bockhorni & Partner DE-C- 41 945 Forstenrieder Allee 59 FR-A- 2 551 178 D-81476 Miinchen (DE) GB-A- 1 682

CO h- o CM CM Note : Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been LU filed until the opposition fee has been paid (Art. 99(1) European patent convention).

Jouve, 18, rue Saint-Denis, 75001 PARIS 1 EP 0 422 047 B1 2

Description ameter and that include a significant number of grains of dimensions in the order of one to two micrometers. This invention relates to gas mantle technology The mantle structures are efficient in converting ther- and more particularly to mantle structures for use mal energy to radiation energy in the visible spectrum with fuel burning devices such as portable fuel- 5 (radiation in the 400-700 nanometer range). burning devices to provide visible radiation. In preferred mantles, the erbia-ceria structure is Incandescent gas mantles were products of ma- fabric-like, for example, in woven, braided, or knitted jor commercial importance in the latter part of the form, and formed so as to provide a self-supporting nineteenth century and into the early part of the twen- dome of erbia-ceria filaments which is heated to in- tieth century. Early mantles, made of oxides of cal- 10 candescence by a gas flame. This dome of erbia-cer- cium, magnesium, zirconium, lanthanum, yttrium and ia filaments can be distorted to a large degree by an the like, provided inadequate lighting power. DE-C-41 external force; in such distortion the filaments bend 945 describes a variety of mantle compositions in- or twist elastically, and when the force is removed cluding mixtures of the above materials with consid- they regain their original shape, restoring the initial erable amounts of ceria; in Example 8 a mantle for 15 configuration of the mantle. Mantles in accordance providing "green-like" light formed from a mixture of with this aspect of the invention are able to undergo 50% thoria and 50% erbia; and in Example 12 a mix- large elastic distortions without fracture. ture of 30% Ceroxyd, 20% Lanthanoxyd, 10% Yttriu- Mantle shock resistance depends upon such fac- moxyd and 40% Zirconoxyd. Thorium oxide-cerium tors as mantle size and shape, characteristics of the oxide mantles (with minor additives) subsequently 20 precursor substrate used in manufacture (such as became the standard for gas light illumination. Those yarn size, type of weave, open area), processing con- mantles, however, have poor strength and durability, ditions and mantle support. Ausef ul shock resistance and also involve problems in both manufacturing and figure of merit for a cantilever supported mantle use. Thorium compounds are radioactive and require whose length and diameter dimensions are similar is special handling precautions which makes those 25 provided, to a first order approximation, by the prod- manufacturing procedures complex, difficult and uct of the shock load (in g's) that the mantle with- costly. Also, those mantles are relatively fragile after stands and the unsupported length (in meters) of the they have been fired. Thoria mantles of greater mantle. The shock load is the force experienced by strength and durability have recently been described, the unsupported mantle as a consequence of rapid as has an yttrium oxide-cerium oxide mantle which is 30 deceleration on impact of the support tube against a alleged to retain its mechanical strength better than stop; this load is commonly expressed in g's, where g commercial thoria mantles. FR-A-2 551 178 de- is the acceleration due to gravity. Impact loads can in- scribes a process in which a woven cloth of combust- volve deceleration forces substantially in excess of ible filaments, such as rayon or cotton, is impregnat- the force of gravity. Mantle structures in accordance ed with an aqueous solution of metal nitrates; and the 35 with this aspect of the invention preferably have a applied nitrates are then converted to the corre- shock resistance figure of merit of at least three g-me- sponding hydroxides with ammonia gas or aqueous ters. ammonium hydroxide. The choice of processing conditions depends on GB 1682 discloses a method for production of the shape and chemical composition of the organic hoods or mantles for gas burners which uses solu- 40 fabric and on the cerium and erbium compounds em- tions including erbium and other elements but no ce- ployed in the embodiment. A preferred organic mate- rium. The mantle is impregnated with the solution and rial for use in producing mantles of the invention is afterwards subjected to heat, so that the fabric is con- low-twist rayon yarn. However, other materials that sumed. absorb adequate amounts of the imbibing solution The invention provides a self-supporting gas 45 and that thermally decompose without melting, such mantle structure with the features of claim 1 methods as cotton, wool, silk and certain synthetic materials of manufacturing the same and preferred embodi- may also be used. ments are characterized in the subclaims. Preferred erbium and cerium compounds are ni- In accordance with one aspect of the invention trates. The erbium and cerium compounds can be im- there is provided an improved gas mantle structure 50 bibed into the organic material (uniformly distributed comprising a self-supporting erbia-ceria structure within the fibrils) by any of several methods. In par- that has golden white color (a color temperature of ticular processes, the fabric is imbibed in an aqueous about 2300K) when energized. The erbia-ceria struc- solution of nitrate salts that have a molar concentra- ture contains from about one percent to ten percent tion of less than 1 .4, preferably in the range of 0.8-1 .1 by weight of cerium oxide and preferably has a shock 55 molar, particular compositions containing erbium ni- resistance figure of merit of at least three g meters. trate and cerium nitrate in concentrations such that The inventive mantle structure is composed of erbia- the final sintered product contains ceria in the amount ceria filaments that are five - ten micrometers in di- of 3.0 - 4.0 weight percent. Minor amounts of other 2 3 EP 0 422 047 B1 4 materials may also be included. made by dissolving nonradioactive nitrates of erbium The elementary erbia-ceria fibers of inventive and cerium in distilled water and mixing the salt sol- mantles have a cross section dimension of less than utions. An organic multif iber fabric in the form of a ten micrometers and the preferred mantle fabric has tubular sleeve is immersed in the imbibing mixture open area of greater than fifty percent. In a dome 5 and gently agitated to promote penetration of the im- configuration that defines a volume of about 0.1 cubic bibing solution into the organic fibers. After imbibi- centimeter and with a skirt portion shrink secured to tion, the sleeve is removed from the solution and a heat resistant support tube, the mantle withstands compressed and then centrifuged to remove surface shock loads in excess of 600 g's. liquid, tied off and formed into a mantle sock, and In preferred embodiments, the mantle filaments 10 dried. The shiny white imbibed mantle sock fabric is contain erbium oxide in an amount in the range from then thermally processed under controlled condi- 90 percent to 99 percent by weight (more preferably tions. Initially, the temperature of the fabric is gradu- in the range from 96 percent to 97 percent by weight); ally increased in an atmosphere that contains a re- and the mantle filaments contain cerium oxide in an duced amount of oxygen (preferably an oxygen par- amount in the range from one percent to ten percent rs tial pressure of less than 1 00 mmHg). Aquite vigorous by weight (more preferably in the range from three reaction, which occurs when the mantle fabric has percent to four percent by weight). The metal oxide fi- reached a temperature of 130-1 70°C, involves an in- laments of such a mantle, after heating in an isobu- teraction (termed herein "nitrate burn") between the tane flame, have a microstructure including a signif- nitrates and the cellulosic fabric, which reaction is vis- icant number of grains of dimensions in the order of 20 ually evidenced by a color change that starts at some one to two micrometers, and are efficient in convert- location in the fabric and produces a front which sep- ing thermal energy to luminous energy in the visible arates a tan color from the shiny white color and ad- spectrum. The flexibility, or ability of the mantlefabric vances through the fabric in a few seconds. This "ni- to undergo considerable elastic distortion without trate burn" reaction involves a partial oxidation of the fracture, is evidence of the strength of this improved 25 cellulose of the fabric by the decomposition products mantle. of the nitrate ions-the gases produced by the thermal In accordance with another aspect of the inven- decomposition of the nitrates being strongly oxidizing tion, there is provided a gas mantle manufacturing in reacting with the cellulose. The fabric is then fur- process that includes steps of imbibing a fabric of or- ther processed in an atmosphere containing an in- ganic material with nonradioactive erbium and cerium 30 creased amount of oxygen (for example, in a heat nitrate compounds, increasing the temperature of the soak interval at about 300°C) during which the re- imbibed organic fabric in a controlled atmosphere at maining cellulose is pyrolyzed and the residual car- a controlled rate to a temperature sufficiently high to bon is removed by oxidation. During this continued thermally decompose the erbium and cerium nitrate thermal processing, an intermediate compound, compounds as a step in the conversion of the erbium 35 ErO(N02)2, if present, is transformed to Er203; the and cerium nitrate compounds to erbia and ceria, the gas evolution slows, but continues until the replica is erbium and cerium nitrate compounds and organic essentially erbium oxide, with a minor amount of ce- substrate material having interaction characteristics rium oxide. The temperature is further increased to such that (in a suitable processing sequence in accor- densify and sinter the erbia-ceria replica. Beneficial dance with the invention) the erbium and cerium ni- 40 sintering and densif ication of the erbia-ceria replica trate compounds undergo thermal conversion to a continues to occur until temperatures of at least about skeletal replica (with healable fissures or rifts) before 1 500°C are reached. The resulting erbia-ceria mantle thermal decomposition of the organic material is com- has substantial strength and light output in the visible pleted; further heating the imbibed fabric to decom- spectrum. pose and remove the organic material from the imbi- 45 Erbia-ceria mantles of the invention, in visual ap- bed fabric (the resulting further gaseous decomposi- pearance, retain characteristic physical shapes of tion products of the organic substrate being removed their organic precursors, although they are substan- from the replica through the rifts) and to complete the tially reduced in dimension. Those erbia-ceria struc- conversion of the erbium and cerium nitrate com- tures are characterized by relatively high density, pounds to erbia and ceria such that an erbia-ceria rep- so strength (preferably a shock resistance figure of merit lica of the organic fabric remains; and further heating of at least three g-meters) and flexibility, and in pre- the erbia-ceria replica to sinter and densify the erbia- ferred mantle configurations are efficient radiation ceria replica such that the densif ied erbia-ceria repli- sources (a luminous efficiency of at least one-half lu- ca that has a strength (shock resistance figure of mer- men perwattand an output of at least ten lumens with it of at least three g-meters, which strength is retained 55 a one gram per hour isobutane flow rate). after the erbia-ceria replica has been heated to Other features and advantages of the invention 1500°C. will be seen as the following description of particular In a particular process, an imbibing mixture is embodiments progresses, in conjunction with the 3 5 EP 0 422 047 B1 6 drawing, in which: damp imbibed sleeves are tied at one end to form Figure 1A is a diagrammatic sectional view of a mantle socks and the formed socks are dried in a flow mantle in accordance with the invention; of warm air and then hung on a support for firing. A Figure 1B is a magnified sectional view of the in- firing process converts the cellulosic mantle socks dicated area in Figure 1A; 5 imbibed with erbium and cerium compounds into Figures 2 and 3 are graphs showing particular mechanically strong mantles that are composed sub- processing sequences for producing mantles in stantially entirely of erbia and ceria and that emit ra- accordance with the invention; diation in the visible spectrum. Figure 4 is a graph of luminous efficiency as a function of Ce/Eratom ration of mantles in accor- 10 Example 1 dance with the invention; Figure 5 is a graph of color temperature as a func- Knit-braided rayon hose (14 needle, 150 deni- tion of Ce/Er atom ratio of mantles in accordance er/60 filament) was soaked for ten minutes at room with the invention; and temperature in an aqueous imbibing mixture contain- Figure 6 is a graph of luminous efficiency as a 15 ing 0.952 M Er(N03)3 and 0.048 M Ce(N03)3, made by function of fuel burn rate of mantles in accor- mixing ten cubic centimeters of a 1.0 M solution of re- dance with the invention. agent grade hydrated erbium nitrate (Er(N03)3.4H20) and 0.5 cubic centimeters of a 1.0 M solution of re- Description of Particular Embodiments agent grade hydrated cerium nitrate (Ce(N03)3.6 20 H20). The imbibed hose was pressed and then cen- Shown in Figures 1Aand 1B is mantle 10 and its trifuged for about ten minutes at about 200 g's to re- support tube 12 as viewed in section through the axis move excess liquid. of tube 12. Support tube 12 is of mullite and has a Lengths of the damp imbibed hose were then length of about twenty five millimeters, an outerdiam- formed into mantle socks by tying, shaping on a pre- eter of about five millimeters and an inner diameter 25 form and drying using a flow of warm air (about 90°C), about three millimeters. Mantle 10 is self-supporting and then placed on a fixture comprising a series of up- erbia-ceria fabric structure that defines a hollow standing mullite posts spaced at intervals of about chamber of about seventy cubic millimeters volume three centimeters on a mullite base. Each mullite post with its tip 14 extending about one-half centimeter be- was about three millimeters in diameter and about 3.7 yond the end 16 of supporttube 12. The skirt 18 of the 30 centimeters long and receives a support tube and mantle fabric (about one-half centimeter in length) is spacer, the top of each support tube being spaced firmly secured to the outer surface of supporttube 12. about five millimeters below the top of the post. Op- The shape of the outer surface of support tube 12 tionally a ring of sodium silicate that has been pre- may be varied to achieve desired mantle configura- treated by heating the tube to about 300°C can be tions, for example, a fluted mantle sidewall shape. 35 carried by the tube. Auxiliary means such as an inorganic cement or a an- The fixture with knitted imbibed formed socks nular recess can optionally used to enhance the se- hung over the support tubes on the posts was then curing of mantle 10 to tube 12. subjected to a firing procedure to convert the erbium The mantle fabric, a portion of which is shown en- nitrate and cerium nitrate imbibed cellulosic mantle larged generally at 20, is formed of erbia-ceria multi- 40 socks into light emitting and mechanically strong filament strands 22 in an open knit array with open- mantles. ings 24 such that the open area of the fabric is about In the processing sequence diagrammed in Fig. sixty percent. Cross-sectional dimensions of the indi- 2, the fixture with the socks was placed in a fifty-two vidual fibers of strands 22 are in the range of 5-10 mi- millimeter inner diameter quartz tube furnace ("Ther- crometers and the strands 22 have cross-sectional 45 molyne" Model F-21125). At ambient temperature dimensions in the order of about 0.1 millimeter with (about 20°C; indicated at point 30 in Fig. 2), carbon di- openings 24 having dimensions of about one-half mil- oxide at a flow rate of sixty cubic centimeters per min- limeter. ute was flowed through the furnace. With this atmos- The erbia-ceria mantle 10 can be made generally phere in the furnace, the furnace temperature was as follows. An imbibing mixture is made by dissolving so then increased at a rate of 8.9°C per minute as indi- salts of erbium and cerium in distilled water and mix- cated at line 32. The mantle fabric underwent "nitrate ing the salt solutions. Multif ibril organic yarn fabric in burn" at about 1 36°C (point 34). At this point the fabric the form of tubular sleeves are immersed in the im- color changed rapidly from white to golden tan. Heat- bibing mixture at room temperature and gently agitat- ing was continued at a rate of about 7.8°C per minute ed to promote penetration of the imbibing solution into 55 as indicated by line 36 to a temperature of about the organic fibers. After imbibition the sleeves are re- 300°C (point 38). During this time the color continu- moved from the solution and compressed and then ously changed from golden tan to dark brown or black centrifuged to remove surface liquid. The resulting with modest shrinkage (about 10%) of the fabric, in- 4 7 EP 0 422 047 B1 8 dicating additional decomposition of the organic ma- time the color continuously changed from golden tan terial. Air at a flow rate about 250 cubic centimeters to dark brown or black with modest shrinkage (about per minute was then flowed through the furnace while 10%) of the fabric, indicating additional decomposi- the temperature was being raised at about 0.4°C per tion of the organic material. Air was then flowed minute, as indicated at line 40, to about 340°C, where 5 through the furnace at a rate about 250 cubic centi- the furnace temperature was held forabout two hours meters per minute as the temperature was raised at sufficient to permit the mantles to turn from black to about 0.4°C per minute, as indicated at line 58, to light gray or white. During this soaking interval in air about 340°C, so that it was held in the range 300°C- the remaining carbon was oxidized and driven off and 340°Cfora time (about two hours) sufficient to permit each dimension of the mantle shrank to about one- 10 the mantles to turn from black to light gray or white. third of its original dimension so that the skirt portion During this soaking interval in air, the remaining car- was shrunk onto its support tube. At the end of the bon was oxidized and driven off and each dimension soaking interval (point 42) the furnace temperature of the mantle shrank to about 1/3 its original value so was increased rapidly, at 37°C per minute, as indicat- that its skirt portion was shrunk onto the support tube. ed at line 44, to a temperature of about 900°C (point 15 At the end of the soaking interval (point 60) the fur- 46). The furnace heater was then turned off and the nace temperature was increased rapidly, at 37°C per furnace allowed to cool to ambient temperature. minute, as indicated at line 62, to a temperature of After cooling, each mantle subassembly was re- about 900°C (point 64). The furnace heater was then moved from its post and exposed to a burning mixture turned off and the furnace allowed to cool to ambient of isobutane and air at an estimated temperature of 20 temperature. about 1600°C for five minutes to further shrink and After cooling, each mantle subassembly 10, 12 densify the metal oxide fabric. was removed from its post and exposed to a burning Mantles 10 formed and shrink fitted to support mixture of isobutane and air at an estimated temper- tubes 12 in this manner were evaluated for shock ature of about 1600°C for five minutes to further strength using a L A B Automatic Drop Shock Tester 25 shrink and densify the metal oxide fabric. (Model SD-1 0-66-30, available from Material Tech- Mantles 10 formed and shrink fitted to support nology Incorporated) which is used with a Type tubes 12 in this manner were evaluated for shock 5520.5.85 Decelerating Device (pulse pad) for shock strength as described above for Example 1 . Mantles loads of up to about 600g's and with a Type 5520.5.28 made as described in this example produced a lumi- Decelerating Device (pulse pad) for shock loads in the 30 nous eff iiciency activated with isobutane at ten sec of range of 600 g's to 1600 g's. Mantles, made as descri- about one lumen/watt (range .96 - 1.01 lumens/watt) bed in this example, survived drop tests at shock at a color temperature of about 2250 K (range 2230 - loads in excess of 900 g's (range 900 - 1150 g's) and, 2360 K), and survived drop tests at shock loads in ex- when activated with an isobutane flame, yielded lumi- cess of about 1000 g's (range 750 - 1350 g's). nous efficiencies of about 0.9 lumens/watt (range .86 35 - .99 lumens/watt) at a color temperature of about Further Examples 2265 K (range 2220 - 2340 K). Further erbia-ceria mantles according to the in- Example 2 vention were made using imbibing solutions having 40 various concentrations and various molar ratios of er- In this example, knit-braided hose was imbibed, bium and cerium, and the mantles so made were test- and imbibed socks were shaped, dried, and hung on ed for luminous efficiency and color temperature. a fixture as described above for Example 1 . Then the Erbium nitrate (99.9% pure) and cerous nitrate socks were subjected to a firing procedure as follows. (A.C.S. grade) were each dissolved in distilled water In the processing sequence diagrammed in Fig. 45 at the following molar concentrations: 0.6 M, 0.8 M, 3, the fixture with the socks was placed in the quartz 1 .0 M, 1 .2 M, and 1 .5 M. These aqueous solutions of tube furnace. At ambient temperature (about 20°C; erbium nitrate and cerous nitrate were mixed in vari- indicated at point 50 in Fig. 3), a mixture of air at a flow ous proportions to yield imbibing mixtures having ce- rate of fifty cubic centimeters per minute and carbon rium:erbium atom ratios ranging from 0.02 to 0.15. dioxide at a flow rate of sixty cubic centimeters per so Nine different such imbibing mixtures were prepared minute (the mixture containing about 9% 02). This at each molar concentration. flow was continued as the furnace temperature was Lengths of braided rayon sleeves were imbibed increased at a rate of 11.3°C per minute as indicated with erbium and cerous nitrate solutions by immers- at line 52. The mantle fabric undergoes a nitrate burn ing them in imbibing mixtures of aqueous erbium and at about 136°C (point 54). At this point the fabric color 55 cerous nitrates prepared as described above for thirty changes rapidly from white to golden tan. Heating minutes and then dried and tied to form mantle socks. was continued at a rate of about 9.5°C per minute to The dried preformed mantle socks were placed over a temperature of about 300°C (point 56). During this support tubes 12 and thermally processed with a pro- 5 g EP 0 422 047 B1 10 pane/air flame to provide erbia-ceria mantles 10 on where the luminous efficiency was in excess of about support tubes 12. 1.1 lumens/watt. Each mantle-tube assembly was operated with a constant supply of isobutane (ten sec/minute), the iso- butane vapor being delivered through a 0.00254 cm 5 Claims (0.001 inch) diameter orifice locatea in the throat of a venturi so that primary combustion air was entrained 1. Self-supporting gas mantle structure (10) con- with the isobutane vapor. The isobutane flow rate was sisting essentially of erbia and ceria, measured using a Hastings H-10 mass flow transduc- characterized in that er and an ALL-10 readout. The air inlet to the venturi 10 said mantle structure is composed of erbia-ceria had an adjustable restriction so that the entrained air filaments that include grains of dimensions in the could be adjusted for maximum light output from the order of one to two micrometers, mantle. said erbia-ceria filaments have a cross section The luminous output of each operating mantle dimension of less than ten micrometers, was measured with a Model 450-1 EG&G, Inc. radio- 15 said mantle structure contains from about one meter/photometer, having a silicon photodiode type percent to ten percent by weight of ceria. detector with a photopic filter. Readings were taken at distances (about 25 centimeters) from the mantle 2. Mantle structure according to claim 1 character- that were large compared to the mantle dimension. ized in that said erbia-ceria filaments are in the For purposes of calculating luminous efficiency, it 20 form of a fabric that has greater than fifty percent was assumed that such a mantle acts like a point open area. source (this assumption being approximately verified in an integrating sphere). The lux reading from the 3. Mantle structure according to claim 1 or 2 char- photometer was converted to lumens and the lumi- acterized in that said mantle contains erbia in an nous efficiency obtained by dividing the lumen read- 25 amount of about ninety-seven percent by weight ing by the gross heat of combustion of the fuel and ceria in an amount of about three percent by burned. Color temperatures were measured with a weight. Minolta Color Meter II. The luminous efficiencies and color tempera- 4. Process of manufacturing a gas mantle structure tures of mantles made using imbibing solutions over 30 according to claim 1 comprising the steps of the entire range of ceria/erbia ratios were measured, imbibing a fabric of organic material with nonra- and at each cerium:erbium atom ratio, mantles made dioactive nitrate compounds of erbium and ceri- using imbibing solutions at the various concentra- um, tions showed no significant differences in resulting increasing at a controlled rate the temperature of luminous efficiency and color temperature. 35 the imbibed organic fabric to a temperature suf- As indicated in Fig. 4, the luminous efficiency ficiently high to thermally decompose the erbium was greatest for mantles made using a Ce:Eratom ra- and cerium nitrate compounds as a step in the tio of 0.04, was progressively less at ratios of 0.06, conversion of the erbium and cerium nitrate com- 0.1, and 0.15, and was also less at a ratio of 0.02. In pounds to erbia and ceria, the range of atom ratios tested, for mantles with an 40 further heating the imbibed fabric to decompose isobutane flow rate of ten scc/min, the color temper- and remove the organic material from the imbi- atures, as indicated in Fig. 5, was highest (about bed'fabric and to complete the conversion of the 2320K) for mantles made using a Ce:Er atom ratio of erbium and cerium nitrate compounds to erbia 0.02, and was progressively less at higher atom ra- and ceria such that an erbia-ceria replica of the tios, about 2265K for a Ce:Er atom ratio of 0.04 to 45 organic fabric remains; and about 2050K for a Ce:Er atom ratio of 0.15. further heating the erbia-ceria replica to sinter A mantle, with a ceria/erbia weight ratio of about and densify the erbia-ceria replica such that that 0.035, was operated over a range of isobutane fuel densified erbia-ceria replica has a strength burn rates from five sec/minute to fourteen sec/min- (shock resistance) figure of merit of at least three ute, and luminous efficiencies were measured, as in- so g-meters, which strength is retained after the er- dicated in Fig. 6. At lower fuel burn rates inadequate bia-cerium replica has been heated to 1500°C. thermal energy was transferred to the luminous man- tle and the mantle ran at cooler temperatures, result- 5. Process of claim 4 wherein said organic fabric is ing in lower luminous efficiencies. At higher fuel burn imbibed in an aqueous solution of nitrate salts rates, the flame lifted off the mantle so that less heat 55 that have a molar concentration of less than was transferred to the mantle, resulting in lower lumi- 1 .6M, and the final sintered product contains cer- nous efficiencies. The optimum operating point was ia in the amount of 3.0-4.0 weight percent. at a fuel burn rate about eleven to twelve sec/minute, 6 11 EP 0 422 047 B1 12

6. Process of claim 4 or 5 wherein an imbibing mix- schwindigkeit auf eine Temperatur, die ausrei- ture is made by dissolving nonradioactive ni- chend hoch ist, urn die Erbium- und Zerium-Ni- trates of erbium and cerium in distilled water, tratverbindungen thermisch zu zersetzen, als said organic fabric in the form of a tubular sleeve Schritt in der Umwandlung der Erbium- und Zeri- is immersed in said imbibing mixture and gently 5 um-Nitratverbindungen zu Erbiumoxid und Zerdi- agitated to promote penetration of the imbibing oxid, solution into the organic fibers, weiteres Auf heizen des getrankten Gewebes, urn after removal of said sleeve from said solution, das organische Material zu zersetzen und aus said sleeve,ve is dried and formed into a mantle dem getrankten Gewebe zu entfernen und urn sock, and 10 die Konversion des Erbium- und Zerium-Nitrat- said imbibed mantle sock is then thermally proc- verbindungen zu Erbiumoxid und Zerdioxid zu essed under controlled conditions, vervollstandigen, so dali ein Erbiumoxid-Zerdi- initially, the temperature of the sock being grad- oxid-Replika des organischen Gewebes ver- ually increased in an atmosphere that contains a bleibt; und reduced amount of oxygen to produce a nitrate 15 weiteres Aufheizen des Erbiumoxid-Zerdioxid- burn, Replikas, urn das Erbiumoxid-Zerdioxid-Replika further heating the sock in an atmosphere con- zu sintern und zu verdichten, so dali das verdich- taining an increased amount of oxygen during tete Erbiumoxid-Zerdioxid-Replika eine Starke which the remaining organic material is pyrolyzed (Stolifestigkeit) von mindestens drei g-Meter auf- and the residual carbon is removed by oxidation 20 weist, wobei diese Starke beibehalten wird, nach- and an erbia-ceria replica of said sock is created, dem das Erbiumoxid-Zerdioxid-Replika auf and 1 500°C aufgeheizt wurde. further heating said replica to densify and sinter said erbia-ceria replica. 5. Verfahren nach Anspruch 4, worin das organi- 25 sche Gewebe in einer walirigen Losung von Ni- tratsalzen getrankt wird, die eine Molar-Konzen- Patentanspruche tration von wenigerals 1 ,6M aufweist und das ge- sinterte Produkt Zerdioxid in einem Anteil von 3,0 1. Selbsttragender Gasgluhkorper (10), bestehend - 4,0 Gew.-% enthalt. im wesentlichen aus Erbiumoxid und Zerdioxid, 30 dadurch gekennzeichnet, dad 6. Verfahren nach Anspruch 4 oder 5, worin die der Gluhkorper aus Erbiumoxid-Zerdioxid-Fa- Trankungsmischung hergestellt wird durch Losen sern gebildet ist, die Kornchen mit Abmessungen von nichtradioaktiven Nitraten von Erbium und in der Grolie von 1-2 Mikrometern umfassen, Zerium in destilliertem Wasser, die Erbiumoxid-Zerdioxid-Fasern eine Quer- 35 das organische Gewebe in Form eines rohrenar- schnittsabmessung von wenigerals 10 Mikrome- tigen Strumpfes in der Trankungsmischung ein- ter aufweisen, getaucht und vorsichtig bewegt wird, urn das Ein- der Gluhkorper ungefahr 1-10 Gew.-Prozenten dringen der Trankungslosung in das organische Zerdioxid enthalt. Gewebe zu fordern, 40 nach der Entfernung des Strumpfes aus der Lo- 2. Gluhkorper nach Anspruch 1, dadurch gekenn- sung der Strumpf getrocknet und in einen Gluh- zeichnet, dad die Erbiumoxid-Zerdioxid-Fasern korpersocken geformt wird, und in der Form eines Gewebes vorliegen, das mehr der durchtrankte Gluhkorpersocken dann ther- als 50% offene Flache aufweist. misch verarbeitet wird unter kontrollierten Bedin- 45 gungen, anfanglich die Temperatur des Sockens 3. Gluhkorper nach Anspruch 1 oder2, dadurch ge- stetig erhoht wird in einer Atmosphare, welche ei- kennzeichnet, dad der Glukorper Erbiumoxid in nen verminderten Anteil von Sauerstoff enthalt, einem Anteil von ungefahr 97 Gew.-Prozent und urn ein Nitratbrennen zu erzeugen, Zerdioxid in einem Anteil von ungefahr 3 Gew.- der Socken in einer Atmosphare weiter aufge- Prozent enthalt. 50 heizt wird, welche einen erhohten Anteil von Sau- erstoff enthalt, wahrendessen das organische 4. Verfahren zur Herstellung eines Gasgluhkorpers Material pyrolisiert und der verbleibende Kohlen- nach Anspruch 1 mit den Schritten, stoff durch Oxidation entfernt und ein Erbium- Tranken eines Gewebes aus organischem Mate- oxid-Zerdioxid-Replika dieses Sockens geschaf- rial mit nichtradioaktiven Nitratverbindungen von 55 fen wird, und Erbium und Zerium, das Replika weiter aufgeheizt wird, urn das Erbi- Erhohen der Temperatur des getrankten organi- umoxid-Zerdioxid-Replika zu verdichten und zu schen Gewebes mit einer kontrollierten Ge- sintern. 7 13 EP 0 422 047 B1 14

Revendications en oxyde d'erbium-oxyde de cerium a ete chauf- fee jusqu'a 1500°C. 1. Structure de manchon a incandescence a gaz auto-porteuse (10) constitute essentiellement 5. Procede selon la revendication 4, dans lequel le- par de I'oxyde d'erbium et de I'oxyde de cerium, 5 dit tissu organique est imbibe dans une solution caracterisee en ce que : aqueuse de sels de nitrate qui presente une ladite structure de manchon a incandes- concentration molaire inferieure a 1 ,6 M et le pro- cence est constitute par des filaments d'oxyde duit f ritte final contient de I'oxyde de cerium selon d'erbium-oxyde de cerium qui incluent des grains une quantite de 3,0 a 4,0 % en poids. dont la dimension est de I'ordre de 1 a 2 micro- 10 metres, 6. Procede selon la revendication 4 ou 5, dans le- lesdits filaments d'oxyde d'erbium-oxyde quel de cerium presentent une dimension en coupe un melange d'imbibition est realise en dis- transversale inferieure a 10 micrometres, et solvant des nitrates non radioactifs d'erbium et ladite structure de manchon contient envi- 15 de cerium dans de I'eau distillee, ron 1 % a 10 % en poids d'oxyde de cerium. ledit tissu organique sous la forme d'une gaine tubulaire est immerge dans ledit melange 2. Structure de manchon selon la revendication 1 , d'imbibition et il est agite doucement afin de sti- caracterisee en ce que lesdits filaments d'oxyde muler la penetration de la solution d'imbibition d'erbium-oxyde de cerium se presentent sous la 20 dans les fibres organiques, forme d'un tissu qui comporte un taux d'ouvertu- apres enlevement de ladite gaine hors de res superieur a 50 %. ladite solution, ladite gaine est sechee et confor- mee selon une semelle de manchon et ladite se- 3. Structure de manchon selon la revendication 1 melle de manchon imbibee est ensuite traitee ou 2, caracterisee en ce que ledit manchon 25 thermiquement moyennant des conditions contient de I'oxyde d'erbium selon une quantite commandees, d'environ 97 % en poids et de I'oxyde de cerium initialement, la temperature de la semelle selon une quantite d'environ 3 % en poids. est augmentee progressivement dans une at- mosphere qui contient une quantite reduite d'oxy- 4. Precede de fabrication d'une structure de man- 30 gene afin de produire un nitrate brule, chon a incandescence a gaz selon la revendica- on chauffe encore la semelle dans une at- tion 1, comprenant les etapes consistant a : mosphere qui contient une quantite augmentee imbiber un tissu en materiau organique d'oxygene, chauffage pendant lequel le materiau avec des composes de nitrates non radioactifs organique restant est pyrolyse et le carbone resi- d'erbium et de cerium, 35 duel est ote par oxydation et une replique en oxy- augmenter selon une vitesse commandee de d'erbium-oxyde de cerium de ladite semelle la temperature du tissu organique imbibe jusqu'a est creee ; et une temperature suffisamment elevee afin de on chauffe encore ladite replique afin de decomposer thermiquement les composes de ni- densifier et de fritter ladite replique en oxyde trates d'erbium et de cerium en tant qu'etape de 40 d'erbium-oxyde de cerium. la conversion des composes de nitrates d'erbium et de cerium en oxyde d'erbium et en oxyde de cerium, chauffer encore le tissu imbibe pour de- composer et oter le materiau organique du tissu 45 imbibe et pour terminer la conversion des compo- ses de nitrates d'erbium et de cerium en oxyde d'erbium et en oxyde de cerium de telle sorte qu'une replique en oxyde d'erbium-oxyde de ce- rium du tissu organique subsiste, et a 50 chauffer encore la replique en oxyde d'er- bium-oxyde de cerium afin de fritter et de densi- fier la replique en oxyde d'erbium-oxyde de ce- rium de telle sorte que ladite replique en oxyde d'erbium-oxyde de cerium densif iee presente un facteur de merite en terme de resistance (resis- tance au choc) d'au moins 3 G-metres, laquelle resistance est maintenue apres que la replique 8 EP 0 422 047 B1

20

TIME (HOURS)

FIG. 2

9 EP 0 422 047 B1

TIME(HOURS)

FIG 3

10 EP 0 422 047 B1

2 3

O Q9|

3 Q8

F/G.4 002 0.04 Q06 Q08 QIO QI2 0J4- 2400 Ce/Er ATOM RATIO

or 2300

§! 2200

2I00 |

2000

FIG.5

g <0 0.02 0.04 Q06 008 QIO QI2 QI4 Ce/Er ATOM RATIO L2-

10-

08-

06-

04-

3 02-

FIGS, 4 8 12 16 FUEL BURN RATE-' ISOBUTANE (SCC/MIN) 11