The application of a mantle to an oil burner is attended by problems differing from the application to a gas burner. In the latter case the pressure of the gas supply is sufficient to induce a draught of air to produce, without other assistance a Bunsen flame. In an oil lamp, however, this gas pressure is absent and to asure the production of a blue flame, intenal and external air supplies are essential to enable the flame orginating at the upper edge of an anular wick to induce sufficient air to produce a blue flame necesary to incandesce the mantle. To produce the maximum incandesence this blue flam must coincide closely in shape and size to the mantle, as otherwise the mantle will produce wholly or partially a red glow of little illuminating power. This difficulty had to be overcome before a satisfactory mantle lamp could be put on the market.
The application of mantles to paraffin burners initiated by Graetz and Mueller was followed by a long series of inventions particularly in the United States, Britain, France, Germany and Sweden, each embodying an attempt to provide a satisfactory mantle lamp but without much commercial succcss. Space will not permit the inclusion of a complete catalogue of all these inventions but there here follows a selection to illustrade the steps wich, after a period of nearly twenty years, enabled a satisfactory mantle lamp to be place on the market.
In 1895 Albin Perlich of Leipzig described an incandescent mantle lamp having a number of wicks side air inlets and a sieve surface on which the flame burns.
The METEOR lamp appeared in 1896 and embodied inventions by a German inventor named Kroll whose company, The Continental Gas Glühlicht Aktien Gesellschaft “METEOR” was formed to market the lamp (Fig.8).
Kroll's fist invention was for refractory bodies for use in gas and other burners which were not specified. His second invention, however, refers to an Argand burner for incandescent lighting. The lamp burner was constructed to provid seperate air currents for volatilising part of the liquid flued and for passing upwards outside the wick to support combustion and the need was reconnized for cooling the lower parts of the burner to prevent over-vaporisation of the liquid fuel. This was a problem wich took many years to solve.
Another german invention is that of Richard Adom. The central feature of this construction was a baffle or cap which was alleged to deflect the flame outwards from the top of the wick and illustrates an early appreciation of the necessity for the flame to be maintained in coincidence with the mantle to obtain the maximum illumination.
A Belgian manufacturer, Leo Durra, was responsible for a mantle lamp construction in 1897 which was primarily concerned with air supply by internal and external air currents. The closed top of the cap, however, would prevent the supply of air to the interior of the mantle and would concentrate both internal and external air supplies to the flame at the mantle skirt.
Kuhnt & Deissler took an important step when, in 1928, they introduced a perforated thimble shaped flame-spreader mounted in the upper end of the inner wick tube (Fig. 9).
This type off flamespreader is an essential feature of mantle lamps at the present day.
A British company, The Era Incandescent Oil Lamp Co. Ltd., was formed in or about the year 1898 to exploit an invention of T. J. Cranston. The invention included a flame spreader perforated in its top and sides co-operating with two annular baffles to direct the air supplies upwards within and around the mantle. The lamp was unsuccessful, however, and the company was wound up in 1903.
During the next ten years a number of endeavours were made to produce a satisfactory incandescent mantle lamp, but with little success. In 1900 and 1901 two companies were formed in the United States of America to exploit mantle lamp inventions.
The earlier was the Standard Incandescant Company of Portland Maine and the later was The Incandescent Petroleum Light Company of St. Louis, Missouri. Both lamps concerned, as well
as others proposed at the same time, included closed top flame spreaders or imperforate flame spreaders, features which practical experience later showed to be ineffective in evenly distributing the central air supply to the mantle. In addition to the companies mentioned there were at the end of the century, a number of firms whose object it was the production of incandescent oil lamps. These included The Continental Gas-Glühlight A.G. and Ehrich & Graetz both in Germany, and the Aktiebolaget Aladin in Sweden. In 1904 Nurnberg described an incandescent mantle burner for gas or oil. It was not a central draught lamp but used a jet of oxygen to induce a supply of combustible gas. In 1909 Carl Blankenberg of Leipzig described a central draught mantle lamp whose construction closely foreshadowed the the type wich ultimately achieved a commercial succes. The Principal features of novelty were a burner cone with inturned annular lip surrounding a perforated inverted thimble flame spreader and a perforated baffle disposed between the cone and the outer wick tube and serve to distribute some of the outer air supply to the exposed wick surface and some to the base of the mantle.
The differences bctween the various endeavours to produce an efficient mantle lamp are exhibited by H. J. Balliantine's lamp in 1910 (Fig. 10)
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In this construction the flame spreader, which has a closed top, is situated well above the burner cone and the flame originating at the head of the wick would tend to overheat the annular members of the air supply arrangements wich surround the flame.
In spite of the endeavours recorded above, mantle lamps made little impact on the public and the reasons for the failure are set forth by Proffessor Vivian B. Lewis in his book Oil Fuel published in 1913, wherein he had this to say on the subject of the mantle lamp:
“So universal has been the adoption of the incandescent mantle with coal-gas that attempts have been made to adapt the mantle to the oil flame, but the difficulties attending success are very great. So rich are the hydrocarbons of the oil-gas flame that considerably more air is required to be mingled with it than with coal-gas. A non-luminous flame can be obtained without much trouble when coal-gas is burnt, but if the flame be superheated it will become to a certain extent luminous again, as the increased temperature causes the decomposition into carbon and hydrogen of the hydrogen molecules in the gas which was prevented when the gas was cool by their seperation and dilution with air. If a mantle be placed on such a non-luminous flame the superheating caused by the mantle itself will have the same result, and in consequence the mantle is soon coated with carbon and its illuminating power largely decreased. If an increased proportion of air be admitted to the flame, the hydrocarbons are burnt up before they can be decomposed by the heated surface of the mantle, and there is no deposition of carbon".