774
T H E J O U R N A L OF I N D U S T R I A L ,4ND E X G I N E E R I N G C H E M I S T R Y .
sists of six cables twelve millimeters in diameter. The three-phase alternating current of fifty periods is transmitted with a voltage of 10,000. A second power station a t Svaelgfos is now under construction. As the normal volume of Mater by a n additional regulation of distant lakes in the same watershed soon will increase to ninety cubic meters, in the new power station likewise two additional units of 10,000H. P. each are built. About sixteen miles farther up the river the first regulating dam a t the Lake of Tinn was constructed a t the same time as the water station of Svaelgfos and the factories a t Notodden. The immense basin regulated by this dam makes it possible to store up fully 300,000,000 cubic meters of water. For the regulation of the water supply a dam was built a t the Lake Mosvand by means of which the level of the lake is raised over 46 feet. As the surface of the lake is not less than 23 square miles, nearly goo,ooo,ooo cubic meters can be retained. The minimum flow in the river is in this way increased from 5-47 cubic meters per second, or the water power a t Rjukan only from 30,000 to 250,000 H. P. To give you some idea of the development of our industry I let pass in review the factories we have had a t the different times: H. P.
Dates. July 1903 Oct. 1903 Sept. 1904 May 1905 May 1907 Nov. 1911
utilized. Factories. 25 Frognerkilens Fabrik.. Anterlokken.. 150 1,000 Vasmoen and Arendal., 2,500 Notodden.................... Notodden and Svaelgfos.. . . . . . 42,500 Notodden. Svaelgfos, Lienfos and Rjukan I . . 200,000
......... .......
................
...........
Employees. 2 4 6
Workmen. 2 10
4 12
20 35 103
143
1 ,340
According to the results of the use of our nitrate of lime, it is stated that it is the same as the Chile saltpeter and for certain soils it is even better. I have the pleasure of telling you that we to-day are sending many thousands of tons of the Norgersalpeter t o California and Hawaii to be applied to the fruit orchards and sugar plantations; and the demand is twice as large as last year. That our nitric acid and nitrate of ammonia are enjoying a good reputation is shown by the following extract from an English periodical, “The Sphere.” It was a peculiar coincidence that just on my trip over here I happened t o see this paper and the article in question. There i t reads--“Nitric acid is the main
Oct.,
1912
constituent of guncotton, dynamite and smokeless powders. One of the chemicals made a t Notodden greatly reduces the heat of discharge, thereby prolonging the life of a big gun,” and further:-(‘Nitrate of ammonia obtained a t Notodden by the marvelous electric process described here, is the principal constituent of many of the explosives for mines and is, therefore, of high importance to the navy.” I could not wish anything better t o be said in favor of our products; you would believe I had put it into the newspaper myself. If you ask me what above all has contributed to such a rapid development of our industry, then I wish to mention the confidence the financial people gave and the good collaboration between engineers and myself. We all were filled with the same thought, to create something great and useful for our country, and we all had in view the great importance this new industry would have from a n international point of view. There is, however, one thing which I wish to tell you and which more than anything else has contributed t o the great success attained in the development of this industry, and that is that I mainly have employed young men for this work. This assertion may appear strange but, I assure you that it is the “lack” of experience which has created this industry. If I had paid attention to all the doubt and hesitation brought forward by the so-called authorities during the development of our enterprise, the Norwegian people to-day would never have their nitrate industry. Thanks t o the young people, to their undaunted courage, energy and love of action the work has been done, and it is in grateful remembrance of all o u r struggles in joy and sorrow, that I look backward t o the work that has been done and the good results we have obtained to-day. The Norwegian nitrate industry is not alone a technical but also a financial success, and I have been able to keep my promise t o the big financial institutions, the Banque de Paris and the Societe Generale, and also to our German associaates, who to-day all are proud of the assistance and confidence they gave t o the industry. My own country, the small Norway, who is the youngest daughter of the family of the electrical industries, does no more need to be proud alone of the discovery of the South Pole, but is glad t o be able to contribute her share in the solution of the most important questions relating to the world’s household.
CURRENT INDUSTRIAL NEWS
1
ny w. A. HAMOR. A NEW WOOD PRESERVATIVE. “Aczol” is a new wood-preserving material, consisting of metallic ammoniates and an antiseptic acid. I t is said to exert no harmful action on either wood or metal. Evidently the use of “Aczol” is based upon the process of permanently fixing large quantities of metallic salts in the wood, as in the patented process of Gerlache, wherein wood is impregnated with an aqueous solution containing free ammonia and amxonia compounds of
copper and zinc ( e . g., ammoniacal solutions of copper sulphate and zinc
AIR COMPRESSOR LUBRICATION.
It is noted in The Engineering and Mining Journal (93, NO. 2 3 , I 125) that explosions within the cylinders of an air compressor are usually caused by the ignition of inflammable gas arising from the use of too much lubricating oil of low flash-point; ,
Oct.,
1912
T H E JOURNAL OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
i t is further pointed out t h a t excessive use of oil tends to give rise to sticking of the valves. Attention is called t o a lubricant which is free from these objections, namely, soapy water with which a small amount of flake graphite has been mixed. The graphite flakes remain suspended in the water until admitted t o the interior of the cylinder, where they exhibit a tendency to attach themselves to the metallic surfaces, imparting a superficial glaze which is smooth, acquires a high polish and prevents actual contact of metal with metal. The soapy water may, however, cause rusting, so i t is advisable to introduce a little oil into the cylinder when shutting down the compressor.
THE OXYGRAPH. The oxygraph, described in The Engineering Record (65, No. 2 5 , 701), is t h e latest appliance developed in connection with the oxy-acetylene-cutting process. It is constructed along the lines of the pantograph, the novel feature being a mechanically propelled tracer which gives uniform speed. The geared tracer is driven by an electric motor attached t o the hqad of the machine. The oxygraph is said t o cut steel 3 in. thick or less, at a speed of 6 in. per minute, and to be capable of cutting curves and right-angled corners. With high quality oxygen, the kerf is very narrow, and the cuts clean and sharp. The work is performed by guiding the tracer along the lines of the drawing on the tracer table, the torch cutting a reproduction in the steel 54' the size of the drawing. The appliance is said t o be useful in die-making and for getting out difficult forms, as blanks for crank shafts of moderate dimensions. THE MANUFACTURE OF LITHOPONE. Lemaire states (Sci. A m . Sup+l., 74, 147) that the manufacture of lithopone is almost confined, in Europe, to Germany. A good deal of secrecy is observed in the manufacture-a fact which seems strange in view of the simplicity of the chemistry involved, but which is justified by the necessity of employing special machines in order to assure the cheapness and uniform quality of the product. The quality of the lithopone depends largely upon the care exercised in the preparation of the two soluble salts, barium sulphide and zinc sulphate. These salts therefore are always prepared in the lithopone factory. Some German firms make a lithopone of the best quality, containing a large proportion of zinc sulphide, from which they obtain lower grades by admixtures of pulverized natural barium sulphate (heavy-spar), which is very cheap, but which absorbs oil far less perfectly than the precipitated barium sulphate which is contained in genuine li thopone. The soluble barium sulphide is obtained by reducing heavyspar (natural barium sulphate) by charcoal a t a red heat, and
' ' *e
*p. *
-71s
of the vessel and its rotary movement produce a n automatic gradation, so that only a finely ground mixture escapes a t B, while the coarser particles remain in the mill for additional grinding. The reduction is accomplished in reverberatory furnaces, retorts or muffles. The operation may be either intermittent or continuous. I n the latter case, the usual one when a reverberatory furnace is used, the mixture is deposited near the front of the furnace and pushed back a t regular intervals. Continuously operating groups of vertical retorts (Fig. 2) or intermittently operating muffle ovens (Fig. 3 ) are also employed.
FIG. VERTICAL RETORTS: C. RETORTS: E , EXTRACTOR: F , FURNACE.
FIG. 3.-MUFFLE OVENS: M , MUFFLER:F,FURNACE.
In both of these cases the losses which are occasioned by oxidation in the reverberatory furnace are avoided, but the consumption of fuel is greatly increased. In the United States, a revolving furnace like the Bruckner apparatus used in soda factories is employed. This furnace gives very good results, but its continuous rotation produces and disseminates dust, which must be removed by a collecting chamber placed between the furnace and the chimney. A furnace of this kind, 6 feet in diameter, 13 feet long, and making one complete revolution in two minutes, suffices for the production of I O tons of lithopone per day. Nagel suggests the employment of the revolving furnace which is used for producing cement clinker, and which operates continuously and consumes little fuel. The hot reduced mass is placed in iron cars, provided with sheet-iron covers, in order to prevent oxidation of the barium sulphide to sulphate, and allowed to cool. The leaching is
. \ FIG. 4.-GAS-HEAYED MUFFLEOVENS: G,RECUPERATOR: M . MUFFLER, P,GAS GENERATOR; V , GAS VALVE:VI. AIR VALVE.
FIG. ~.-HARDINGETUBEMILL.
leaching the mass after cooling with water. The heavy-spar and charcoal, according to Nagel, should be ground and mixed together in revolving tube mills, which can be cheaply operated. I n the United States, the Hardinge tube mill (Fig. I) is coming into use. The heavy-spar and charcoal are introduced a t the end A and the pulverized mixture passes out a t the opposite end B. Although the. apparatus contains no sieve, the conical form
accomplished in double-bottomed vats or in the Shank apparatus employed for the leaching of crude soda in the Leblanc process. The operation must be conducted rapidly in order to prevent oxidation. All that part of the factory which is devoted to the preparation of barium sulphide should be separate and distant from the rooms in which the manufacture of lithopone takes place, for the smallest trace of charcoal dust or natural barium sulphate would destroy the whiteness of the lithopone. Natural barium sulphate is often very impure and frequently contains salts of iron and other metals. A trace of iron salt in the barium sulphide makes the lithopone sensitive to the action of light. Such traces of impurity are removed by methods which have been kept secret. In Germany the zinc sulphate employed is obtained from
