The " slack indicator " of Messrs Siemens Brothers & Co.
The Siemens polarized relay, shown in fig.
- Siemens FIG.
Gintl of Vienna in 1853 and in the following year by Frischen and by Siemens and Halske.
The most successful apparatus of this kind is that devised by Wheatstone; others were devised by Siemens and Halske, Gartner, Humaston, Siemens, and Little.
In one well-known form, called a Siemens Electrodynamometer, there is a fixed coil (fig.
- Siemens Electrodynamometer.
It was not, however, a commercial success, and the same result attended Siemens and Halske's application of the silent discharge.
In 1888 the Dowlais Iron Company (now Messrs Guest, Keen & Nettlefold, Ltd.) acquired here some ninety acres on which were built four blast furnaces and six Siemens' smelting furnaces.
Alexander Siemens (Journ.
In 1890 he was appointed director of the Siemens laboratory at King's College, London, with the title of professor of electrical engineering.
15) employed for melting glass are usually heated with gas on the " Siemens," or some similar system of regenerative heating.
Siemens (Comptes rendus, 1904, 138, p. 1299).
(b) Both the producer gas and the air are heated before they enter the combustion chamber, as in the Siemens system of regenerative firing.
The cause of the spongy deposit is variously explained, some (Siemens and Halske) ascribing it to the existence of a compound of zinc and hydrogen, and others, among whom are G.
Siemens and Halske have proposed the addition of oxidizing agents such as free halogens, to prevent the formation of zinc hydride, to which they attribute the formation of zincsponge.
In 1878 Sir William Siemens patented a form of furnace' which is the type of a very large number of those designed by later inventors.
It is for this reason that Siemens, Borchers and others substituted a hollow watercooled metal block for the carbon cathode upon which the melted metal rests while in the furnace.
The arc furnaces now widely used in the manufacture of calcium carbide on a large scale are chiefly developments of the Siemens furnace.
But whereas, from its construction, the Siemens furnace was intermittent in operation, necessitating stoppage of the current while the contents of the crucible were poured out, many of the newer forms are specially designed either to minimize the time required in effecting the withdrawal of one charge and the introduction of the next, or to ensure absolute continuity of action, raw material being constantly charged in at the top and the finished substance and by-products (slag, &c.) withdrawn either continuously or at intervals, as sufficient quantity shall have accumulated.
The production of ozone in small quantities during electrolysis, and by the so-called silent discharge, has long been known, and the Siemens induction tube has been developed for use industrially.
The Siemens and Halske ozonizer, in form somewhat resembling the old laboratory instrument, is largely used in Germany; working with an alternating current transformed up to 650o volts, it has been found to give 280 grains or more of ozone per e.
Siemens and Halske, essentially consists in the electrolysis of weak solutions with iron or steel plate anodes, and lead cathodes, the latter, when coated with gold, being fused and cupelled.
Siemens has pointed out that a profile of the sea-bed can be delineated by taking account of the varying strain on a submarine cable while it is being laid, and the average depth of a section can thus be ascertained with some accuracy.
In general construction the instrument resembles a Siemens electrodynamometer (see Amperemeter).
In this case both the fixed and movable circuits consist of fine wires, and the instrument is constructed and used in a manner similar to the Siemens dynamometer employed for measuring continuous alternating current (see Amperemeter).
The institutions include a museum of local antiquities, a grammar school, the Siemens Convalescent Home and the Ilkley Bath Charitable Institution.
Knowing this, and having in the Siemens regenerative gas furnace an independent means of generating this temperature, the Martin brothers of Sireuil in France in 1864 developed the open-hearth process of making steel of any desired carbon-content by melting together in this furnace cast and wrought iron.
Like the Siemens furnace, described in § 99, they have two distinct phases: one, " on gas," during which part of the waste gas of the blast-furnace is burnt within the stove, highly heating the great surface of brickwork which for that purpose is provided within it; the other, " on wind," during which the blast is.
The " pig and ore " or " Siemens " variety of the process works chiefly by oxidation, the " pig and scrap " or " Siemens-Martin " variety chiefly by dilution, sometimes indeed by extreme dilution, as when Io parts of cast iron are diluted with 90 parts of scrap. Both varieties may be carried out in the basic and dephosphorizing way, i.e.
The general plan of the open-hearth process was certainly conceived by Josiah Marshall Heath in 1845, if not indeed by Reaumur in 1722, but for lack of a furnace in which a high enough temperature could be generated it could not be carried out until the development of the Siemens regenerative gas furnace about 1860.
Siemens Open-Hearth Furnace.
- Diagrammatic Sections of Tilting Siemens Furnace..
These regenerators are the essence of the Siemens or " regenerative furnace "; they are heat-traps, catching and storing by their -11, Ton Traver 7s 20 Tan Tra y.
This defect is usually remedied by heating the pits by the Siemens regenerative system (see § 99); the greater FIG.
Flexibility thus gained outweighs the cost of the fuel used and the increased loss of iron by oxidation by the Siemens gas flame.
In the intermittent system the waste heat can, it is true, be utilized either for raising steam (but inefficiently and inconveniently, because of the intermittency), or by a regenerative method like the Siemens, Fig.
19; but this would probably recover less heat than the continuous system, first, because it transfers the heat from flame to metal indirectly instead of directly; and, second, because the brickwork of the Siemens system is probably a poorer heat-catcher than the iron billets of the continuous system, because its disadvantages of low conductivity and low specific heat probably outweigh its advantages of roughness and porosity.
Siemens, who presented it to the Berlin Museum.
Siemens effected a great improvement by inventing a shuttle armature and improving the shape of the field magnet.
1833), Siemens, Wheatstone, W.
Varley (1828-1883), Siemens and Wheatstone (see Dynamo).
Siemens in Paris in 1881.
Meanwhile the early continuous current dynamos devised by Gramme, Siemens and others had been vastly improved in scientific principle and practical construction by the labours of Siemens, J.
Siemens on the electric furnace was continued and greatly extended by Henri Moissan and others on its scientific side, and electro-chemistry took its place as one of the most promising departments of technical research and invention.
Siemens and Halske introduced a combined process in which the ore, after being part-roasted, is leached by solutions from a previous electrolytic operation, and the resulting copper solution electrolysed.