Scientific worthies : [No.] 29, Sir Joseph Lister / [Hermann Tillmanns].
- Hermann Tillmanns
- Date:
- [1896]
Licence: Public Domain Mark
Credit: Scientific worthies : [No.] 29, Sir Joseph Lister / [Hermann Tillmanns]. Source: Wellcome Collection.
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![Mr. Richards, and the only cure for the evils he enumerates is to improve the intelligence and the status of the working classes. It is with regret that Englishmen too often see continental employers superior to those of this country in regard to the thoughtful care bestowed upon their workpeople. In some cases it is true, care of the workman is forced upon the manu¬ facturer by legislation, but in a great many instances the continental iron and steel maker has recognised the wisdom of treating his workpeople liberally. Doubtless in England we may find many large-minded employers who, either from self- interest or from motives of a higher character, pay much atten¬ tion to the well-being of their workmen, but too often the “hands” are looked on as simply an extension of the plant, their sole function being to give the maximum of labour on the minimum of outlay. It is hardly to be wondered at, under these circumstances, that self-seeking persons obtain the ear of the working man in this country, and so often advise them to their own detriment and that of the nation at large. Mr. Windsor Richards concluded his address with some remarks on technical education. Referring to the want of intelligence on the part of operatives he said, ‘ ‘ yet the favourite remedy of this state of things is, in many minds, to spread technical education all over the country ; whereas if the results they desired unhappily be attained, the last state of the trade would be worse than the first, for we should have no hewers of coal, nor makers of steel.” “Technical education” is so un¬ certain a quantity that it is not easy to arrive at what Mr. Windsor Richards exactly meant by his expression. We think, however, that his words are likely to be misleading if not mischievous. The most hopeful solution of the labour problem, in fact the only solution, is higher intelligence on the part of the workman, and there is no better way of fostering this intelligence than by giving operatives such knowledge as will enable them to appreciate the processes in which they are engaged. Experience proves that a man does not become less efficient as a labourer, even as a hewer of coal and a maker of steel, because he is educated, although frequently he may, by virtue of his education, rise above these positions. We must, however, leave Mr. Richards’ address, and turn to the other parts of the proceedings. At the last meeting of this Institution, a paper by Mr. W. H. Patched, on “ Steam Superheating” was read, the discussion on which was adjourned until the present meeting. Mr. Patchell’s paper referred to various designs of superheater, the principal one treated upon being that of McPhail and Simpson. In this apparatus steam is taken from the boiler and passed to a super¬ heater which utilises the waste gases from the furnace. In this way the steam acquires a certain amount of superheat. It is then taken back to the boiler, and circulates in the water space of the latter by means of an internal pipe. After this it passes to the engine. The object of the invention is to obtain thoroughly dry steam without the risk of it being highly super¬ heated, and thus cutting cylinder faces, or leading to defects which have been experienced in time past in using steam above the temperature normal to the pressure. It will be seen, of course, that this superheater, so called, is not necessarily a superheater at all ; it may be, or may not be, the result depending on the quantity of heat imparted to the steam by the waste gases, and to the length of time the steam is subjected to the influence of the water in the boiler by means of the internal pipe. Supposing the steam be superheated several degrees and then returned to the boiler, it will be subjected to the influence of water at a lesser temperature than itself, for the water in the boiler is practically at the temperature of saturated steam due to the boiler pressure. The superheated steam may be reduced to that temperature, but will not fall below it. Practically, we believe, in an installation with a McPhail superheater, as usually designed, the steam finally emerges from the internal pipe at a temperature above that due to its pressure, but generally to a small extent. It will, of course, be dry steam on finally emerging from the internal pipe; though possibly, in some cases, surface radiation in the steam pipe between the boiler and the engine may deprive the steam of its superheat. It is further to be noted that the heat which the superheated steam parts with, to the water in the boiler, is not lost, but goes to aid evaporation. If the degree of superheat of the steam as t passes into the engine cylinder be small, some of the steam will be almost immediately liquefied by the usual process of extraction of heat incidental to the working of any steam engine. If the heat used for superheating be wholly waste heat, there will of NO. 1384, VOL. 54] course be a gain due to the adoption of the apparatus ; but against this must be put the first cost of the superheater. In any case it is an advantage to get dry steam, and the McPhail device must be credited with this. The principal contribution to the discussion was made by Prof. W. C. Unwin, who claimed that Plirn should be credited with the practical introduction of the use of superheated steam. In Alsace he said superheaters are generally in use, and are found to be of great practical value. If the apparatus were intelligently designed, it was possible to use superheated steam without any of the dangers and troubles of which so much had been heard. A few years ago superheaters were largely fitted to a large number of steamships in the form of the well-known steam chimney, as doubtless the majority of our readers are aware. The advent of higher pressures, and consequent higher tem¬ peratures, however, brought difficulties. When steam'of 30 to 60 lb. pressure was used, it was possible to increase the temperature of steam above that normal to the pressure, without introducing much complication, but when temperatures rose much above those mentioned, as they speedily did with the advance in boiler practice, superheating became a more serious matter. Improvements in the packing of glands, and the intro¬ duction of mineral lubricants, now enabled still higher tempera¬ tures of steam to be used without danger. It may be as Prof. Unwin says, that we can take useful example from the Alsatian practice, and thus another era of superheating has arisen. The introduction of the water tube-boiler also may supply an incentive to marine engineers in this direction. The limited water and steam space with this type of generator make it often difficult to get dry steam, so that a superheater would fill a useful place. Another point to be observed is, that if superheating of steam be used, steam jacketing is not necessary, or at any rate not so necessary as when non-superheated steam, often containing a considerable quantity of water, is passed to the engine. Perhaps when the paper on steam jackets by Messrs. Hudson and Donkin is read, we may get further light on this subject, and it is to be hoped ample time will be given for its discussion. Mr. MacCarthy’s paper on “ Electric Welding of Steam Pipes ” was a valuable and interesting contribution. Higher steam pressures have brought trouble to the marine coppersmith. The old brazed copper pipes have been found, by sad experience, to be dangerous fittings, several lives having been lost by their failure. Steel pipes have been accordingly substituted where high pressures are used ; and so far as the pipes themselves are concerned, there is not much difficulty in producing a trust¬ worthy article. The longitudinal welds of a lap-welded pipe are made either by rolls or by the gas-welding system with a hammer, in a thoroughly satisfactory manner, and .experience has shown how flanged junctions can be made. It is where joints, such as elbows, T-pieces, &c., are required that the difficulty .arises, and it is here that electric welding has come to the help of the marine engineer. On the table of the theatre Mr. MacCarthy exhibited several very fine specimens of steam fittings of the kind referred to, a four-way branch being a notable example. These were all made by the Benardos system of arc welding. Flanges are also welded to the length of pipe in the same manner ; the method of working was described by the author as follows :— “ Ordinary low-tension continuous-current lighting dynamos are used; to the terminals of these a battery of Benardos accumulators is connected, into which the current flows con¬ tinuously. When the welding circuit is closed, the current flows from the dynamos and accumulators; and large resist¬ ances are used when necessary. In this way a large discharge is obtained, equal to about twice the capacity of the dynamos, and the load factor of the apparatus is high. For some purposes it is possible to work without accumulators; but when this is done, the efficiency of the apparatus is not so high, because during part of the working period no current whatever is passing, and the machinery is running light.” For attaching the flanges to the pipeS, the following method is adopted :— “ The flange is stamped out under the steam hammer in such a way that a V-shaped groove is left on the inside edge, extend¬ ing about three-fourths through the thickness of the metal. The flange is next shrunk upon the tube, with its flat face outwards or at the end of the tube, and is carefully set in the exact position required. The welding consists in laying small pieces of steel in the V-shaped grove, and welding them in one by one by means of the electric arc, the welds being freely hammered between](https://iiif.wellcomecollection.org/image/b30592069_0022.jp2/full/800%2C/0/default.jpg)
