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to Lewes,” “If the humus be slowly heated, a large proportion of the oxygen is given off in combination with hydrogen as water vapor, but if the temperature be raised quickly a larger proportion combines with the carbon to form carbon monoxide and dioxide.”
retorts, chamber ovens, and by-product coke ovens as compared with horizontal gas retorts no doubt have much to do with the greater concentrations of carbon disulfide generally observed in horizontal retort practice. I n these comparisons a probable contributing factor is the variation in secondary decomposition of the carbon disulfide on the Variation in Large-Scale Carbonizing Processes coke surface after the gas is formed. To coke high-sulfur coals with the minimum of carbon hIoreoi-er, the experimental findings of Hutton and Thomas2 disulfide resulting, our present information indicates that are in accord with the experimental observations just given. the operator should choose that carbonizing process which It will be recalled that these experimenters found an increase offers a slow rate of heating, and also, if possible, an extenin carbon disulfide concentration both when higher tem- sive travel of the formed gas over heated surfaces. peratures were employed and when smaller coal charges Further Investigations were burned off. I n both cases the increase in carbon disulfide attends an increase in the rate of temperature Limitations upon the passage of the gas over heated coke change, for, as Hutton and Thomas observed, “with the surfaces may, however, be revealed by a study of the hydrogen smaller charge, the temperature rise through the mass is sulfide, carbon, and carbon disulfide reactions a t tempermore rapid.” atures higher than those covered by the preceding experiA variation in the production of carbon disulfide is noted mental work. as the charge in a horizontal retort is carbonized. This An extension of this study may indicate the part played yariation during the distillation is probably related to pro- by the pyritic and organic coal sulfur. gressive variations in the rate of temperature change in The importance of the rate of heating in determining different parts of the retort. However, these temperature the chemical form of the sulfur in the gas indicates that changes are governed by conditions which are very complex this rate must have an important influence upon the mode and imperfectly understood. The fracturing of the coke of decomposition of the sulfur in the coal, the so-called and the effect of this upon the path of the travel of the gas re-absorption of the sulfur during carbonization, and the is one complicating factor. It is therefore difficult to relate amount and distribution of the sulfur in the coke. Previous this variation in carbon disulfide production with these studies have developed such points chiefly through labtemperature changes. oratory investigations in which the coal was heated slowly. The low rates of heat transmission encountered in low- A further investigation to include the rate of heating as temperature carbonization explain the absence or lowered an important variable may give information which more production of carbon disulfide in some such processes. The closely parallels commercial conditions. lowered rates of heat transmission prevailing in vertical Further consideration of the origin and decomposition of carbon disulfide within the water-gas machine is suggested. 17 Loc. c i t . p. 1%
A Foam Meter‘ By H. Earnest Williams 961 MAPLEAvE., MORSEMERE, N. J.
HERE are few referencesin theliterature to methods for measuring the foaming tendencies of liquids and the foam-reducing power of oils used for removing froth. The methods to which reference may be found involve agitation of the mixture to be tested in a graduated tube, and the height to which the froth rises above the surface of the liquid Ts the basis on which conclusions are drawn. Kryz2 uses a device consisting of a wooden float carrying a n upright rod to which is attached a strip of paper, whose color is changed by the moisture in the foam. I n the method of Trotman and Hackford3 the mixture is mechanically shaken in a graduated tube and the height to which the foam rises is measured. -4method used in testing the foaming tendency of beer4is based on the same principle. Recently it was necessary to test the foaming tendency of certain paint-like liquids and the efficiency of diverse foamreducing greases and oils. Owing to the opacity of these liquids it was impossible to note between which marks on a graduated tube the foam on an agitated mixture was contained. Furthermore, there was froth on the surface of the liquid as well as air interspersed throughout the mass. Con-
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1
Received October 23, 1928. 70 (1924). Farben-Zlg., 16, 2291 (1921). A m Brewers’ Reu., 26, 270, 6 , 3119 (1911).
* Oesferr. Chern.-Zfg., 27, 3 4
sequently, since a volume measurement of the foam could not be made, an attempt was made to base measurements on weight. I n operating the apparatus to be described no attempt is made to weigh foam or froth itself. Apparatus and Method
The top of an acid bottle was removed and inverted to form a bowl. At the bottom of the bowl, in the neck of the bottle, was placed a rubber stopper ,bearing a glass tube. The upper end of the tube did not project beyond the stopper into the bowl, and to the lower end of the tube was attached a rubber tube which could be closed with a pinchcock. Around the top of the bowl was placed a wooden collar on which was mounted an egg beater, to the driving wheel of which was wired a pulley so that the beater could be beltdriven by an electric motor. The cold-water paint to be tested was poured into the bowl, the pinchcock being closed, until the bowl was two-thirds full, the mixing part of the beater blades being submerged in the mixture. After stirring the material for 3 minutes the motor was stopped and the pinchcock was a t once opened wide to allow the beaten liquid to run into a weighed flask placed under the outlet of the rubber tubing. The total volume of the flask is called the “foam meter volume”
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(F. M. V.) and to secure comparable results the flask should be standardized. Its volume should be considerably less than that of the material taken for the test.
T’ol. 18, No. 4
be attached, the agitation being controlled by a revolution count during: - a definite time interval. A bath should be provided maintaining constant the temperature of the material to be agitated. Other types of stirrers could be used in case stirring alone were desired. Practical Application
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W e i g h t of F. M.V. as Affected by C e r t a i n F o a m - R e d u c i n g S u b s t a n c e s Ratio F. M. V. unagitated Weight of material F. M. V. to agitated Test RBDUCSR AMOUNT Grams materialY 1 None 238.5 1.81 2 Vegetal 16 8 grams 258.5 1.68 3 Vegetal 268.5 1.62 4 Vegetal 36 grams 305.5 1.42 5 Zavon 8 grams 328.5. 1.32 6 Penetral 8 cc. 340.5 1.28 7 Ketone B 321.5 8 cc. 1.35 8 Glycerol 231.5 8 cc. 1.88 9 Alcohol 8 cc. 239.5 1.82 10 Ether 8 cc. 272 1.60 I1 Carbon tetrachloride 8 cc. 201.5 2.16 12 Gasoline 255 8 cc. 1.67 a Agitation 3 minutes at room tempt !rat.me, 250 r. P. m. of large wheel of beater.
Th/s pulley tobe 90od on sfud with ashft/e s i d e p l a y us possible fit
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The apparatus has found practical application in testing the foam-reducing power of numerous antifrothing oils suggested for reducing the foaming tendency of certain papercoating substances. Equal amounts of these liquids were mixed with definite weights (or volumes) of diverse foamreducing materials and the weight of the I?. M. V. after agitation of the treated mixtures was found, as shown in the accompanying table.
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The greater the weight of the F. M. V. in any case the less air there is in the agitated material. The results show that the mixture used in Test 6 has the least tendency to become foamy. The relative value of the foam-reducing materials is thus seen. The instrument will indicate changes taking place in a cold-water paint to which the foam reducer has been added. The F. M. V. of the material after agitation for 3 minutes was 301.5 grams. A sample of the original treated material was agitated after it had stood for 1 hour and the weight of the F. M. V. was then 284.5 grams, and a t the end of 2 hours the material when agitated gave a reading of 268.5 grams. The foam reducer was effective a t the outset in preventing the accumulation of foam in the agitated liquid, but changes taking place in the mixture later retarded the escape of foam in the beaten material and low reading resulted. The length of time necessary for agitation in case the instrument is used for measuring the foaming tendency of a lead paint would, of course, differ from that required for an aqueous glue solution. The conditions for standardization, however, could readily be ascertained for any industrial mixture. This method of measuring foaming tendencies would seem to warrant a chance to display its capabilities, and it is hoped that this paper will act as a stimulus to others to do further work with it.
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After sufficient foamy liquid has run out to fill the flask (with whatever runs out, foam or liquid or both) the pinchcock is closed. A spatula is passed over the top of the flask to level off any head, and the flask and contents are weighed. The. foaming liquid weight is found by subtracting the weight of the dry flask from the gross weight and from this net weight the volume (F. M. V.) may be calculated. I n testing two paints one of which foams more readily than the other, the one in which the foam will not accumulate will give the greater F. M. V. weight. We can therefore express the foaming tendency of paints, varnishes, glues, creams, and paper coatings numerically on the basis of the ratio of the weight of the material placed in the bowl at the outset to the weight of the F. M. V. of material after whipping. The method of testing could be modified by weighing the material remaining in the bowl after the F. M. V. is removed. The features of this apparatus were later incorporated in one made of brass, the details of which are shown. The q. 0. valve was soldered to the bottom of the bowl. For precise work a counter for the revolutions of the stirrer should
Wesleyan University Receives Research Fund WGsleyan University announces an anonymous gift of 3340,000 to be used by the department of chemistry of the university for the purchase of research apparatus. According to information received from Prof. C. R. Hoover, $10,000 of the fund is to be expended before July 1, 1927, for the purchase of research equipment for the Hall Laboratory of Chemistry, which is now under construction. The income derived by the investment of the balance of the fund-about $1600 per year-will be expended by the department for the purchase of research apparatus and supplies; a t least one-third of the income must be expended upon research in pure chemistry.
