Page 4 - Demo

pagepage44%u2022 Issue 101 %u2022 December 2019 %u2022Historic Gas TimesThe year 1884 marked the start of the experiments by Carl Auer von Welsbach, an Austrian chemist, to achieve incandescence by experimenting with various chemicals. Whilst others had demonstrated that some of the rare earths are capable of emitting light when heated by a suitable flame, Welsbach discovered that a very much higher level of incandescence could be achieved by using a mixture of certain chemicals in definite proportions. Some say that it was apparently by chance that the flame from a Bunsen burner he was using touched a piece of material that had become soaked in the chemical/s he was working with that was his %u2018eureka%u2019 moment. The result was a sudden bright incandescence. Following doubtless hundreds of experiments Welsbach established the chemical composition that was to transform the world of gas lighting. However, it still took many years for %u2018the mantle%u2019 to become a truly practical product as it was such a fragile item.Eventually, the company did market a mantle under the brand name Sugg Stronga with this wonderful space inspired advert!The first Welsbach mantle was the one we now call the %u2018upright%u2019 mantle and indeed explains why Welsbach christened it a %u2018mantle%u2019 as it was placed over the Bunsen flame like a sleeveless cloak or %u2018mantle%u2019. It was simply a matter of converting the upright open flame fixture to an aerated burner using Bunsen%u2019s principle and placing the mantle over the flame. The mantle was cylindrical and naturally faced upwards resulting in the light from the mantle being largely sideways and upwards.Whilst these experiments continued, the light from the upright mantle was still being projected away from the direction in which it would be most useful, i.e. downwards and it was this that eventually led to the production of the %u2018inverted%u2019 mantle, first produced in 1903.The picture shows a selection of mantles with five sizes of inverted mantle at the back, %u2018upright%u2019 on the left and one version of the %u2018supervia%u2019 mantle that was used with multi jet nozzles giving a directional source in later high-performance street lamps. The tiny mantle known as a %u2018limina%u2019 mantle on the right was used in a small signal lamp usually running permanently.In an attempt to increase the amount of light from both upright and inverted mantles, both were enlarged until it was discovered that there was a limit to the amount of gas/air mixture that would burn within the mantle such that it heated the maximum surface area of the mantle to incandescence without destroying the mantle mesh which of course was literally ash when %u2018burnt off%u2019. For quite a long time in the development of the mantle for street lighting they were so fragile that Suggs even made a burner with an antivibrating device in the early years of the 20th century to reduce mantle failure through vibration travelling up the lamp post from passing traffic.The first Windsor model has a steeper %u2018tent%u2019 (roof) than the now more familiar Model %u2018B%u2019. This is the Jan 1906 List 12 catalogue cover showing single upright burner with anti vibrator. Note the claim %u201cOver 50,000 of our Windsor Lamps are now in use%u201d This lamp was designed in 1898 for the new incandescent burner. It never carried an open flame.When %u2018inverting%u2019 the mantle the secret lay in forming a strong aerated flame with a pure blue cone for maximum heat pointing downwards and the size (volume) of the mantle once again had to match the amount of mantle material that the flame could fully heat. This turned out to be a shape much nearer a short round bottomed cylinder, not far from being spherical by comparison with the long upright mantle.The Windsor lamp was offered with a twin inverted burner including an anti-vibrator mounting but at the same time Suggs introduced a new %u2018shadowless%u2019 lamp, the Regent, designed to take advantage of the inverted mantle utilising a number of complete inverted burners mounted equi-spaced around the circular body of the lamp with individual mantles.The %u2018shadowless%u2019 aspect relates to the shadows that the side ribs of the traditional lantern would throw on the ground.Having enlarged mantles in attempting to get higher lighting performance it became clear that the smaller mantles were by proportion stronger and longer lasting than the larger mantles. The discovery that it was possible to mount several mantles together on one manifold %u2013 that Suggs called a %u2018superheater%u2019 %u2013 was a game changer because, in addition to longer lasting mantles, the performance was improved by pre-heating the gas as it passed through the superheater.This arrangement was known as the %u2018Littleton Principle%u2019 and most if not all the Regent lamps were converted in due course, whilst the MARY POPPINS RETURNSTHE REAL STORY BEHIND THE GAS LAMPS AND LAMPLIGHTERSPART 2