As there is very little technical litterature relating to the development of mantle lamps it has been nescessary to rely to a large extent for detail of evolution on patent specifications, but all those referred to from 1910 onwards have been used in practice in the lamps sold under the trademark "Aladdin". The production of the mantle lamp is thus an interesting eexample of a light engineering industry which developed for many years under the protection of a large series of patents. Acccordingly there has been little competition. During the period 1920-1930 competing lamps appeared, but owing to the protection afforded by the patents owned or controlled by Aladdin Industrics Ltd. competing lamps could not be provided with the improvements which imparted a unique degree of efficiency to the "Aladdin" lamp.
To ensure to the users of mantle lamps a supply of paraffin of the high grade necessary for maximum illumination, and at the same time eliminate carbon deposit on the mantle, Aladdin industries Ltd. made an arrangement with Shell Mex Ltd. to supply a high grade paraffin which was coloured pink and by advertisement users of the lamps were advised to use only Pink paraffin to ensure maximum lighting efficiency.
Modern mantle lamps both as table lamp and hanging lamp are still being manufactured in substantial quantities by Aladdin Industries Ltd., as although the demand has fallen off in this country due to the increased facilities for electric lighting in all parts of Great Britain, there are many places in Asia, Africa and South America where electricity is not available. The demand for these lamps in Middle Eastern countries is so considerable that manufacture is now taken place in Iran for distribution in that country as well as in Iraq and Afghanistan. Certain components, notably the mantle fittings, are being manufactured in India and arrangements are being made for the manufacture of complete lamps in that country.
Aladdin Industries Ltd. manufacture at Greenford, Middlesex, and at Pontardawe in South Wales, all metal lamp components as well as the woven wicks and the mantles. The chimneys, wich involve skilled operations, are made by a firm specialising in glass manufacture. Lamps are normally products having a long, usefull life, but the mantles and wicks, being more quickly consumed, form an important part of the industry. The developments described above, especially those applicable to burner structures, wicks and chimneys have also found a useful application in the construction of oil burning space heaters.
The pressure lamp
This account of incandescent oil lamps concludes with a description of the pressure lamp, that is one wherein means are employed to increase air pressure within the reservoir to force the liquid fuel upwards to the burner. The lamps so far described for indoor domestic use did not need this additional pressure, as the air intake arrangements are such as to provide an air supply to the wick and mantle sufficient to produce a blue frame.
Portable lamps or lanterns for outdoor use such as on farms), however, present additional problems, since to guard the burner parts against the effects of draughts and wind it is to enclose the burner, mantle and their associated componentswithin a glass shell or globe. This Construction precluded the introduction of a suffienct supply of air to produce a blue flame and necessitated the redesigning of the entire lamp structure.
There has always been a need for a portable lantern for a variety of rural purposes and the old type lanterns which employed candles or alternatively burnt oil directly from a wick, gave poor and restricted illumination so that as the mantle lamp developed for indoor illumination, inventors turned to the solution of the problems attending the employment of incandescent mantles in portable oil lanterns.
An early form of pressure mantle lamp produced in 1895 includes an upright mantle and a means for producing pressure in the fuel recevoir to cause vaporisation of the liquid fuel.(Fig. 16).
A pressure lamp evolved in 1907 by Aktiebolaget Aladin of Sweden, also shows a primitive form with a pre-heating arrangement for the burner as in this and succeeding pressure lamp designs, vaporisation of the liquid fuel is effected by arranging the supply tube close to the mantle, which thereby heats and vaporises the fuel within the tube. Obviously, no vaporisation can take place until the tube is heated and consequently a pre-heating device consisting of a small annular tray supplied with methylated spirit or the like is provided. A further development of a pressure lamp burner employs two inverted mantles and is provided with means for preventing free carbon from reaching the burner orifice.
A pressure lamp evolved in 1930 includes as new feature a pre-heating torch supplied from the lamp recevoir to heat the vaporiser before the main burner can be ignited and the inverted mantle rendered incandescent (Fig. 17).
Later, another construction was proposed to with a curved vaporiser disposed around the burner connected to a supply conduit disposed outside the glass wall or chimney, which enclosed the burner and mantle. The experience gained by the exploitation of the pressure lamps described above has enabled the present construction to be succcssfully evolved and operated.
A modern pressure lantern includes a pump in the fuel reservoir to create air pressure which forces the fuel to ascend the feed pipe which passes through the inverted mantle to a mixing chamber to which air is supplied through three radial inlets. From the mixing chamber the mixture of vaporized fuel and air passes to a jet orifice within the mantle (Fig. 18).
A pricker is provided to enable the jet orifice to be claered from time to time of any deposited solid matter. A spirit cup and asbestos wick surround the base of the feed pipe. The whole of these arrangements are enclosed with a glass bowl.
The end of the mantle lamp is not yet. For indoor illumination it still fines a use in this country, in places where gas and electricity supplies are not available, while for ornamental purposes (such as for table illumination) it possesses the advantage that no cable or gas connection is needed. For many places overseas the mantle lamp provides the best illumination available and so its manufacture will continue for many years to come.
In conclusion I wish to thank the Directors of Aladdin Industries Ltd. for allowing access to their records; Mr. Robert H. Jacob of Chicago, Attorney for Aladdin Industries Inc., and Mr. V. S. Johnson Junior, for information on the early development of mantle lamps; also Mr. K. J. Eagland for preparing the illustrations.