The Flame Disc
The burners of this type differ from the Kosmos burners at first sight in that they have a special attachment at the upper end of their wick tube, called the flame disc (or also "flame spreader" or "flame diffusor"). This is why these burners have generally been called flame disc burners.
This special attachment, which protrudes from the centre of the wick tube, either has a flat, round disc attached to a thin pin or tube, or resembles a hat that sits on a wide tube with small holes. The flame disc fulfils two important tasks: Firstly, it serves to force the tubular, cylindrical flame of the wick to widen and thus it creates a larger flame surface. Secondly, it presses the inner draft, which must flow upwards along its disc, against the inner flank of the flame. These two measures result in a flame that is spread more or less like a basket and burns brighter with the forced, more intensive contact with the air.
The flame disc is not an integral part of the burner; it is simply inserted into the wick tube and is almost always easily removable, which is a misfortune in retrospect, because today, for example, many burners of this type (or lamps that have such a burner) are offered on eBay, however without the accompanying flame disc, because it has been lost in the meantime! A burner of this type is useless without the correct flame disc, because a conceptually prepared, optimal burning with a broad, bright flame is impossible without the corresponding flame disc.
The invention of the flame disc happened much earlier, in 1840's in Liverpool ("Liverpool button"), to make the flame of the Argand burner (still with oil!) even brighter. The first flame discs consisted of a simple disc with a relatively small diameter, which sat on a thin pin. To accommodate this pin, the burner had a narrow tube in the middle of the wick tube. The pin could be inserted into this narrow tube to a certain depth so that the small flame disc had the optimum distance to the upper edge of the wick tube and thus also to the wick, as determined by empirical tests.
This flame disc, invented for oil burners, was later also used in the round burners for kerosene/paraffin. The shape and size initially remained the same. The expansion of the flame was rather modest due to the relatively small disc.
A few years later, however, the diameter of the flame disc was enlarged in order to achieve even wider flames with more light output. These larger discs still sat on the conventional metal pins or narrow, long tubes, but the greater flame width now required wider glass chimneys at the bottom. Well-known German and Austrian burner manufacturers invented a plethora of intricately constructed flame discs, which had the simple flat disc at the top, but with quite imaginative shapes at the bottom as spacers to the inner wick tube, an essential distinguishing feature. The size of the flame disc also determined the type of glass chimney to be used on this burner (see chapter Glass Chimneys).
A significant leap forward in improvement did not come until around 1884, when Rochester Lamp Co. in the USA introduced a new type of flame disc (patented by Leonhard Henkle), which differed from the previous flame discs in every respect. It consisted of a cylindrical tube, the upper end of which was completely closed and the lower end completely open. The sides of the tube were provided with countless small holes. This tube fitted exactly into the opening of the wick tube; one virtually closed off the top of the inner wick tube with this thimble-like flame disc. The many small holes on the wall of the tube were used to direct the inner air flow to the inner flanks of the flame, which enabled better combustion of the kerosene/paraffin, resulting in a brighter flame. This new type of flame disc was a great market success in the USA. It became almost a trademark for all central draft lamps. The US Americans were tireless in constantly changing the shape of this flame disc to increase its effect. Every change, no matter how small and unimportant, was immediately patented. The patent data were meticulously immortalised on these flame discs, which was certainly not a hindrance in the competition for market shares. The consequence of this flame disc hysteria was that, on the one hand, every American lamp manufacturer installed countless flame discs of different appearance in their lamps, and on the other hand, the flame disc acquired a rather unusual status, because it now usually also bore the logo of the lamp company and not the wick knob, for which only the wick knob was intended in Europe.
This American flame disc also came to Europe with some delay, where it soon acquired a different and more uniform appearance. Here, a broad disc, which looked like a flattened hat and was slightly curved downwards at the sides, sat on the broad tube with small holes. I call this flame disc "hat on sieve tube" to describe the type concisely and unmistakably.
Some flame discs of different types
Top row, from left: Lampe Belge, Lempereur & Bernard, Liège
15‘‘‘ Brillant Meteor burner, R. Ditmar, Vienna
15‘‘‘ Elektra burner, Gebr. Brünner, Vienna
20‘‘‘ Intensiv burner, Schmidt & Jaedicke, Berlin
#2 center-draft burner, Bradley & Hubbard, USA
Bottom row, from left: 30‘‘‘ Blitz lamp burner, ULUM, Hoffmann, Sebnitz
#2 center-draft burner, Bristol Brass & Clock Co., USA
20‘‘‘ Saturn burner, R. Ditmar, Vienna
15‘‘‘ Titus burner, Wetzchewald & Wilmes, Neheim
10‘‘‘ Splendidus burner, R. Ditmar, Vienna
Flame Disc Burners with Side-Draft
As is well known, the first round burners were the Kosmos burners, which differed from the Argand burners used until then by their lateral air intake. The elongated, in many cases triangular opening on the side of the wick tube made it possible for the first time that such burners could be used on any reservoir for kerosene/paraffin, as they did not need an air tube that went through the tank and had to be open at the bottom. All of a sudden it was possible to use kerosene/paraffin fonts of completely different materials than metal. The great age of glass fonts with all their design possibilities was born! This great advantage of lateral air supply was an epoch-making achievement in every respect. The aim was to retain this advantage in as many further developed burners as possible. As a result, the side air supply was retained in a large number of larger burners developed in Germany in 1880-1900.
The trend during this period was clearly towards larger burners producing higher brightness, as lamps also became larger, more ostentatious over time to satisfy a growing and demanding clientele. The Kosmos burners were most effective at small and medium sizes. As the size grew, one could not get the flame brightness one hoped for respectively. The large Kosmos burners were therefore uneconomical. The large burners with the appropriate flame disc closed this gap very advantageously.
The first large burners of 15-20 lines from German and Austrian development had a small disc on a thin pin or tube. The corresponding glass chimneys ("shoulder chimneys"; see chapter on Glass Chimneys) were also quite similar to the Kosmos chimneys. These round burners did not yet have the dominant deflector extended upwards. In their outer appearance, they were therefore more similar to the Kosmos burners. But the attached flame disc, as small as its diameter was, was able to do its job well in the combination of the shouler chimney used for more intensive air contact of the flame.
Almost all well-known burner manufacturers in continental Europe had burners with a small flame disc in their range. The best known among these manufacturers were Carl Holy (Odin burner, Brillant burner), Ehrich & Graetz (Rex burner), Stobwasser (Victoria burner), Carl Rakenius (Mars burner), all in Berlin, and R. Ditmar (Sonnenbrenner = Sun burner) in Vienna.
Some burners with small flame disc on pin or tube
From left: 14‘‘‘ Victoria burner of Stobwasser, Berlin
15‘‘‘ Rex burner of Ehrich & Graetz, Berlin
15‘‘‘ Sonnenbrenner (= Sun burner) of R. Ditmar, Vienna
16‘‘‘ Odin burner of Carl Holy, Berlin
20‘‘‘ Odin burner of Carl Holy, Berlin
The even larger burners with 20-25 lines needed a wider disc on their flame disc to be able to broaden the flame correspondingly and more effectively. These burners now had a considerably extended deflector at the top, so that it even protruded above the wick tube in some burners. The upper edge of the deflector was slightly curved inwards to direct the air onto the flame. As a result, the flame was first pushed inwards a little, only to be pulled apart like a basket immediately afterwards by the wide disc of the flame disc. All these measures had only one aim: to create an ever more intensive air contact with the flame. Due to the much wider flame, wider glass chimneys were now also necessary ("bottle-shaped chimneys"; see chapter on Glass Chimneys).
Around 1890, the burners with the larger flame disc dominated the market. The early survey catalogues by Stoll and Goldberg list many such burners, which possibly represented the "non plus ultra" for burners of the time. Of course, almost all German burner manufacturers were again on the market with corresponding burners.
After many years of manufacturing Kosmos burners, Wild & Wessel developed their first flame disc burner from their Kosmos burner, the “Kosmos Vulkan burner”, which still resembled a Kosmos burner but had a large flame disc on a thin pin. From this, the Vulkan and Central Vulkan burners were developed with a very innovative, perfectly fitted glass chimney. These burners did not need a decidedly upwardly extended deflector, because the task of such a deflector was now taken over by a specially developed glass chimney ("Kniff/Kugel-Zylinder" in German; translated: “pinched/bulged chimney”; see chapter on Glass Chimneys).
Among the many other German manufacturers were again Carl Holy (Concurrenz burner), Stobwasser (Prometheus burner), Schubert & Sorge (Intensiv burner), C.F. Kindermann (Columbus burner), Kästner & Töbelmann (Adler burner), to name but a few. There were many others who had such burners in their program. In Austria, Gebr. Brünner was represented with their Brillant-Reform burner.
Some burners with large flame disc on pin or tube
From left: 16‘‘‘ Central Vulkan burner of Wild & Wessel, Berlin
20‘‘‘ Prometheus burner of Stobwasser, Berlin
20‘‘‘ Brillant Reform burner of Gebr. Brünner, Vienna
20‘‘‘ Concurrenz burner of Carl Holy, Berlin
20‘‘‘ Columbus burner of Kindermann, Berlin
After the emergence and great success of the completely differently designed thimble-shaped flame disc in the USA, its appearance and marketing in Europe was only a question of time. The fact that its market success in Europe started rather late was due to the great dominance of the German burners on the market, who still held on to the concept of the large disc on the pin. The dam was broken at the latest when Ehrich & Graetz launched their famous Matador burner with the new “hat on sieve tube” type of flame disc in 1895! These burners were such a great market success that all burner manufacturers now endeavoured to develop and market similar burners with the same flame disc. Even the renowned company Wild & Wessel was forced to follow this market trend and developed the Agni and Kronos burners with a similar flame disc. With the market success of the Matador burners, the formerly dominant German burners with the flat flame discs were pushed out of the market.
This type of burner with the hat-like flame disc also had countless imitators. Every well-known burner manufacturer produced similar burners, with slight modifications of the hat-like flame disc, and called their burners with different fantasy names, as the name "Matador" was a trademark of E&G. With some competitor burners (e.g. Augusta burner by Otto Müller, Ideal burner by Brökelman, Jaeger & Busse, Hugo burner by Hugo Schneider, Gladiator burner by the French company Societé Industrielle), it is sometimes very difficult to find any differences at all compared to the Matador burners by Ehrich & Graetz!
Some burners with flame disc of the "hat on sieve tube" type
From left: 20‘‘‘ Matador burner of Ehrich & Graetz, Berlin
20‘‘‘ Bürger burner of Carl Holy, Berlin
20‘‘‘ Agni burner of Wild & Wessel, Berlin
22‘‘‘ Kaiser burner of Eckel & Glinicke, Berlin
22‘‘‘ Titan burner of Kästner & Töbelmann, Erfurt
The flame disc burners had finally established themselves as the better burners on the market. Simple or small lamps were still equipped with Kosmos burners, as their efficiency (=emitted brightness in relation to spent paraffin) was very good, especially with small burners. But the large, handsome salon lamps with many decorations demanded larger, more advanced burners. Here, the flame disc burners were the better choice, although they also consumed more kerosene/paraffin due to their larger dimensions. So it is not surprising that all well-known lamp and burner manufacturers had a large selection of such burners in their range.
The White-Light Burner
A slight, but now clearly visible deviation from the shape of the round burner described above occurred in the late 19th century when, under the competitive pressure of the much brighter incandescent mantle lamps, so-called white-light burners were developed which deviated from the usual shape of the round burner in that their basket had a cylindrical shape and was much longer in height in order to allow the larger amount of air to flow in that was necessary to produce a brighter, whiter (hence the name) flame.
The flame disc of these burners also deviates from the shape of the flame disc of the "hat on sieve tube" type described above. One went back to the "thimble" type as it was developed and patented 20 years ago by Leonhard Henkle in the USA. This shape is indeed comparable to a thimble, with the difference that it is strictly cylindrical and not conical like a thimble.
This "thimble" type flame disc therefore did not have the task of pushing the flame wide, but simply to contact it with as much air as possible. Because the flame was not widened, it was now possible to use completely cylindrical glass chimneys without any bulge. The flame produced was therefore more cylindrical and somewhat raised due to the increased air supply. The hoped-for success on the market did not occur; the incandescent burners could not be successfully combated because the brightness of the white-light burners did not reach the high light intensity of incandescent lamps. The reason was simply that more air supply, i.e. more oxygen supply for combustion did not automatically produce a proportionally corresponding high brightness, but in part caused a higher flame temperature; you got a much hotter flame!
Explanation: The light generation of a burning flame is based on the fact that individual carbon particles contained in the molecules of the hydrocarbon chains, which have become gaseous due to the heat of the flame, heat up for a while to such an extent that they begin to glow and emit their incandescent light before they are completely burnt and thus converted into carbon dioxide gas. The reaction of carbon with oxygen to form carbon dioxide (chemically speaking, combustion is oxidation) is exothermic. This means that a lot of heat is released during this chemical reaction. This is also the reason why a flame is very hot. So first there is a gasification process, i.e. conversion of the kerosene/paraffin components into a gaseous state. Then these components are heated to such an extent that they reach their "glowing temperature" and emit light. In this phase, the individual carbon atoms behave like extremely small bodies, like “micro-incandescent mantles”, which glow. Shortly afterwards, they combine with the oxygen in the air, form the gas carbon dioxide, release heat in this reaction, and escape in gaseous form from the top of the glass chimney into the room. Over time, the fine art of burner development has produced burner designs that have greatly optimised the light emission phase just before final combustion. And this happened entirely without computers, but only through long-term, patient, empirical trial and error.
The incandescent burners use the exothermic reaction of carbon combustion very specifically to heat the special, very incandescent metal oxides (cerium and thorium oxides) embedded in the incandescent mantle up to their incandescent temperature. Their burners are designed in such a way that most of the kerosene/paraffin is burnt not to produce a brightly glowing flame, but to form an almost blue flame that does not glow, but is much hotter. It is this high heat that causes the mantle to glow with a bright light. Due to their construction, some incandescent burners are reminiscent of white-light burners; they are often equipped with a similar, cylindrical or slightly conical basket, which is, however, relatively squat and widens considerably at the upper end. The flame discs used are also very similar, as they are of the same thimble type. An important distinguishing feature is the suspension device for the mantle made of a metal wire that protrudes upwards from the burner basket. This similarity can be problematic, as old mantle burners are very often offered without the associated suspension wire for the mantle, and thus confusion with conventional white light burners is possible.
Two white-light burners with their wick tubes and flame discs
Left: 20‘‘‘ Intern burner of Kästner & Töbelmann, Erfurt
Right: 20‘‘‘ Maxum burner of Eckel & Glinicke, Berlin
Flame Disc Burners with Center-Draft
The third variant of round burners is again based on Argand's principle, in that they do not get their air supply through an opening in the side of the burner, but exactly according to Argand's design, from below through a pipe open at the bottom. Their great difference (apart from the burning fluid used) from the old Argand oil burner is that they now use a flame disc, thus allowing optimum combustion of the kerosene/paraffin with high light yield. The disadvantage of this design - as also described above - is the need for a fixed pipe in the font. As a result, only metal fonts (almost always made of sheet brass) can be used to firmly solder the tube for the central air supply at the bottom. This means that the great variety of fonts made of other materials such as glass, porcelain, etc. is lost. A second disadvantage is the forced determination of the burner to be used; since the tube for the central air supply is also the inner wick tube, the rest of the burner must be exactly adapted to it. The result is a kerosene/paraffin tank combined with a precisely matched burner that cannot be easily replaced. Changing the burner, as is very possible with the burners with the side air supply, is impossible here. Of course, it is also possible to change a defective burner with central air supply, but only with a burner of identical construction from the same manufacturer.
Two countries built a large number of central-draft lamps and also marketed them very successfully: Belgium and the USA. In Belgium, it was Lempereur & Bernard who introduced this type of lamp to the market, and their successors Louis Sépulchre, Moreau Frères, Caby and Albert Wauthoz. In the USA, this type of lamp ("center-draft lamps") really conquered the market after Rochester Lamp Co. integrated the special thimble-like flame disc with the sieve tube into their lamps. Many other American lamp manufacturers followed this example. All American "Gone with the wind" lamps (see chapter American Lamps) use a brass font with a central draft, which in turn is inserted into painted glass vases.
German and Austrian lamp manufacturers have often used burners with a central draft in larger hanging lamps rather than designing them as table lamps. The perceived subordinate market presence of central-draft lamps in these countries comes from the immense variety and prevalence of table lamps with the side-draft burners.
Some burners with central draft and their flame discs
From left: 20‘‘‘ burner for Triumph lamps of Ehrich & Graetz, Berlin
15‘‘‘ burner for Favorit lamps of R. Ditmar, Vienna
Burner of Sepulchre, Liège
18‘‘‘ burner of Moreau Frères, Liège
Burner of New Rochester Lamp (1892), Rochester Lamp Co., USA