T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
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Vol. 13, No. 7
A Rotary Digester for Use in Bagasse Analysis' By Guilford L. Spencer THECUBAN-AMERICAN SUGAR COMPANY, N E W YORK, N. Y.
The determination of sugar in cane bagasse, with the customary digesters, usually presents difficulties through the need of keeping the material in motion while treating it with hot water. Motion is necessary to promote maceration a n d diffusion. Following the digestion, the extract must be cooled and, without special arrangement, this is a slow process. Further, many bagasse tests must be made daily in full control of cane milling. To permit attention to other duties, the chemist must be relieved of as much of the immediate supervision of the bagasse tests as is possible. To facilitate this testing, the author has devised a rotary digester, which is simply a steam bath in which cylinders, containing the sample and water, are rotated. The apparatus is fitted for three simultaneous tests. The casing of the digester is cylindrical and of 24-in. internal diameter. A triangular hub, 4 in. long, turns freely with a shaft, which is fitted with an adjustable cone bearing inside the digester casing at one end, while the other end projects through a bronze bearing and carries a pulley 18 in. in diameter. The pulley is grooved for a sewing machine belt or a light chain. Clamps are provided on the hub for attaching three aluminium cylinders, 4 in. in diameter by 8 in. long, for samples. The clamps also hold the covers of the cylinders in position. The covers have break-vacuum cocks. The pulley is connected through a laboratory reducing gear, 48: 1, with a small electric motor, and is rotated a t about 5 r. p. m. The cylinders
are revolved endwise. A hinged cover closes the apparatus when in use. The casing is drained by a 1-in. pipe, provided with a stop valve. A 1-in. overflow pipe leads from a point below the shaft and connects with the drain below the stop valve. The apparatus is provided with a 0.125-in. steam pipe and a 0.5-in. cold water pipe. The following is the procedure in making a sugar test with this digester: 100 g. of chopped bagasse are weighed in a tared cylinder; 1liter of very hot water is added; the cover, with the cock closed, is placed in position on the cylinder and this is then locked on the hub. If ammonia is used in preserving the material while collecting the sample, no alkali is added to the digestion water; otherwise sodium carbonate is added. The cover is closed,and withthe bottom drain open steam is turned into the casing. Very little steam is needed. With the outlet to the drain open, the pressure is that of the atmosphere. The cylinders are revolved for an hour in the steam and this is then shut off, and the drain is closed; cold water is now admitted and the revolution of the hub is continued until the sample is cooled. The drain is opened, and the cylinder is removed, dried, and weighed. Further procedure is as in the customary methods of analysis. As may be noted, the slow motion of the hub causes the bagasse to fall from end to end of the cylinder, agitates the extract, and promotes maceration and diffusion.
Continuous Sampling of Sugar Liquors' By Walter L. Jordan 83 WASHINGTON PLACE, NEWYORK,N. Y.
Sampling of sugar juices and liquors is of first importance in mill and refinery control. Exact analytical work in the laboratory will have little value if the samples do not truly represent the products that are going through the mill or factory. Usually samples are taken periodically. The men a t the various stations are given bottles to be filled at intervals of 1 or 2 hrs. The sample is dependent upon the sampler, and he soon learns to take samples that show his own work to be satisfactory, instead of those that will correctly reflect
Methods now used for sampling liquids automatically, as far as the writer is aware, all give a sample the volume of which is dependent upon the time element and bears no relation to variations in flow of the liquid sampled. Thus if a drip sample is taken, a small flow through the main pipe line adds just as much to the sample as a large flow, If
FIG.3
FIG. 1
FIG.2
manufacturing conditions and assist in the process control. 1 Presented before the Section of Sugar Chemistry and Technology a t the 61st Meeting of the American Chemical Society, Rochester, N. Y., April 26 to 29, 1921.
a t the same time the composition of the juice varies, it is evident that such a sample cannot be representative of the total juice flowing. A sample proportional to the total flow may be obtained by the circular weir shown in Fig. 1. The sample is that portion overflowing through the vertical slot. This device can be applied wherever the liquor to be sampled flows into a receiving tank, measuring tank, defecator, etc. Instead of the juice or liquor running into the tank through a downward turned nipple or fitting, this is turned up so that the pipe fills and the juice spills over the level edge of the
July, 1921
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
fitting. The size of the sample obtained is dependent approximately on the relation between the width of the slot and the total weir circumference. Actually, the sample will be smaller than indicated by this proportion, on account of the fact that the sides of the slot restrict the flow sbmewhat. The depth of flow is the same, however, for the slot and for the balance of the circumference. A 10-in. in diameter weir with a 0.25-in. slot in a 1-in. wide plate will give a sample of about one one-hundred and twentieth of the total liquid flowing; or with an 0.125-in. slot, one two-hundred and fortieth.
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Fig. 2 illustrates the relation between the width of the sample slot and the total weir. A funnel constructed of light sheet metal and soldered to both sides of the slot plate serves to carry off the sample. If the volume of liquid is very large, it may be necessary to reduce it twice, as in Fig. 3. I n a mill grinding 2000 tons of cane per day, the juice may thus be reduced to a bucket sample per 6-hr. shift. Drainage cocks are indicated to empty the pipe lines a t shutdowns. The sampler can be made up of standard pipe fittings in any mill shop.
ADDRESSES AND CONTRIBUTED ARTICLES Incendiaries in Modern VVarfare’~2*3 By Arthur B. Ray UNIONCARBIDEA N D CARBON RESFARCH LABORATORIES, INC.,LONGISLAND CITY, N. Y.
The destructive action brought about by the natural elements-fire, air, and water-may be looked upon as infinite when compared with the damage which can be caused by other means in a brief period of time. In harnessing one of these natural elements-fire-and applying it as a war weapon, we have assurance of its efficacy in the universal dread in which i t is held as the most ruthless enemy of mankind. The idea of using incendiaries in warfare is not modern: in fact, the use of fire as a destructive weapon dates back to early Biblical times, when burning oils and ignited fire balls consisting of resin and straw were thrown both by the defenders and attackers of fortified towns. In later times crude iron latticework bombs up to 2 f t . in diameter, filled with highly flammable materials, were ignited and projected by catapults or thrown from fortifications. The iron skeleton of such a medieval bomb may be seen in the Tower of London. But, while, from the earliest times, fire has been considered to be of possible military value, means for scientifically using i t as a powerful weapon were not developed until the recent war. The effectiveness of incendiary armament is dependent upon the character of the incendiary materials employed and upon the devices by means of which the materials are carried to the target and set in action there. The development of this type of armament, therefore, involves both chemical and mechanical investigative work which must be done in close cooperation with those who are fully conversant with the military requirements and limitations. I shall endeavor in this paper to point out the general characteristics of all the typical materials and devices developed by the warring nations and to discuss, in their proper place and in somewhat greater detail, the more important developments with which we were intimately connected in the United States. The materials and devices will be discussed separately in so far as it is possible to do so. P A R T I-INCENDIARY
MATERIALS
Since the many devices differ widely as to action, it is obvious Presented before the Division of Industrial Chemists and Chemical Engineers a t the 58th Meeting of the American Chemical Society, Philadelphia, Pa., September 2 to 6, 1919. 2 This articIe is published by permission of the Chief of the Chemical Warfare Service. 8 Very soon after our entrance into the war the development ofincendiary armament was begun in this country by the Bureau of Mines and continued by the Chemical Warfare Service in cooperation with the Ordnance Department. Investigations concerning all the desired forms of armament, except incendiary small arms ammunition which was developed a t Frankford Arsenal, were carried out at the American University Experiment Station b y the Incendiary Section, under the direction of Capt. Arthur B. Ray, C.W. S., and by the Pyrotechnic Section, under the direction of Major G . A. Richter, C. W.S.,with the invaluable assistance of the Ordnance Department. 1
that no one incendiary material can be used. In fact, for practically every device a special material has been developed to give the desired result as to time of burning, kind of flame, kind of reaction products, etc. For convenience of discussion, we may classify all the incendiary materials as follows: White phosphorus, thermite, oxidizing agent-combustible mixtures, flammable materials used as such, the special material called “solid oil,” and spontaneously flammable liquids. PHOSPHORUS On account of its property of igniting spontaneously when exposed to air, white phosphorus was early suggested as an incendiary material, and a number of devices, such as bullets, bombs, shells, and grenades, which depend upon it for incendiary effect, have been developed and used. Against substances which can be ignited by a momentary exposure to a small flame, phosphorus undoubtedly is of value, but for setting fire to materials which are relatively difficult to ignite, phosphorus is of very little value, because of its low temperature of burning and because the phosphoric oxides formed act as an excellent fireproofing material. Bullets containing phosphorus have proved to be very eff ective against hydrogen-filled aircraft and against airplanes when the gasoline tank is punctured. The phosphorus pellets which these bullets carry are cast or cut from rods and are coated with aluminium dust-the aluminium acting both as a preservative while handling and as an intensifier of the flame when the bullet functions. The bullets are so designed, as will be shown later, that when fusible plugs in the side are melted by the heat of friction, the phosphorus is exuded and burned. The path of the bullet may be followed by the trail of smoke. Grenades and 4-inch Stokes’ mortar bombs containing phosphorus were effectively used against personnel, particularly when exploded in dug-outs. The inconvenience caused by the obnoxious smoke and scattered burning particles of phosphorus was considerable.
THERMITE The well-known properties of the aluminium-iron oxide mixture called thermite caused it to be widely used, in various modified forms, as an incendiary material. Such mixtures have the advantage that when ignited they produce an enormous amount of heat very quickly and that the molten metal and slag resulting from the reaction will penetrate metal and prolong the incendiary action upon flammable materials. These mixtures when used alone, however, have the disadvantage that the incendiary action against, say, wood structures is confined to a very small area, and that a very large percentage of the heat energy set free is wasted because it is set free too rapidly to be utilized effectively, except by very flammable material. Since
