THE MANUFACTURE OF SUGAR BY DIFFUSION AT MAGNOLIA, SEASON OF 1888.

The beginning of the work at Magnolia was a series of disappointments. First of all, the cane cutter did not work satisfactorily, but finally, after many vexatious delays on this account, we succeeded in obtaining a maximum cutting capacity of less than 200 tons of straight cane per day, and often when the cane was very crooked less than 150 tons were cut. As soon as our cutting difficulties were fairly overcome all the calorisators of the battery were discovered to leak so badly that all work was stopped for repairs. During the intervals when the battery was not in operation, milling was employed for the extraction of the juice. This alternate use of the mill and battery has complicated results to such an extent that it is impossible to separate the work of the early part of the season, hence I am compelled to credit all, up to a certain period, to the mill. It must surely prove a disappointment to all Louisiana sugar producers that these irregularities prevented a careful study of diffusion throughout the season.

The diffusion work, of which we have a complete separate record, commenced December 1, and continued to the end of the season. In this time we had a serious loss in the bone-black room. Unfortunately we are compelled to include this in our record of diffusion work. This of course affects in some degree the value of these results, especially to planters who do not use bone-black filters.

In the general averages for the crop, the diffusion work is compelled to help out the average of the mill work. This is a heavy burden to bear, since the work of the mill on 2,700 tons, augmented by that of the diffusion battery on 500 tons of cane, will average at least 40 pounds of sugar less than the diffusion yield on two-thirds of the crop. I have made a separate statement of the work of the diffusion battery, and trust that those interested in the investigation of this process will examine this statement without being biased by the comparatively low average of the entire crop.

THE CUTTER.

The cutting apparatus was the same as that used in the Department's experiments last season. It was built by the Sangerhauser Company, of Sangerhausen, Germany. The cutter consists essentially

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of a horizontal disc carrying twelve knives set parallel to the radii of the disc, and revolving in a cast-iron shell. There are six cane chutes or hoppers placed at an angle of about 45 degrees to the surface of the disc. The cane, thrown lengthwise into the chutes, descends by gravity to the knives, where it is sliced diagonally. A suitable arrangement for throwing the chips into the elevator boot is provided. This cutter was designed by the builders to revolve one hundred and ten revolutions per minute, and its capacity was guaranteed to be from 200 to 250 tons of chips per twenty-four hours. After overcoming numerous and serious faults in the construction of the cutter and increasing its speed to one hundred and eighty revolutions, an increase of 63 per cent., we were enabled to cut 195 tons of chips from straight cane in twenty-four hours, the largest day's work we accomplished.

Mr. Fred Hinze, an able and experienced sugar manufacturer, had charge of this work, and through his skill we were enabled to overcome the difficulties in preparing the cane for the battery. Last season, after the first failure of the cutter, Dr. Wiley ordered small steel scrapers to be attached to the upper surface and side edge of the cutting disc. The cane was very juicy in 1887, hence he was enabled to cut nearly 1,000 tons of cane without appreciable wear of these scrapers. This season, on the contrary, the cane was exceptionally woody, and scrapers of the best file steel were worn out in cutting less than 400 tons of cane. In addition to the trouble with these scrapers, it was found that the fibers from the cane collected between the disc and outer shell and soon com. pletely blockaded the cutter. Mr. Hinze had openings cut both in the cover and upper part of the shell to relieve the disc of the accumulations of fiber. It was only after these alterations were made that we were able to use the cutter at all.

Economical diffusion of sugar cane demands an exceedingly thin slice or chip. With our best work we were unable to obtain a chip less than an eighth of an inch thick. This is double the thickness required by good work.

Taking into consideration the large labor bills, difficulty in regular adjustment of the knives, and impossibility of obtaining a sufficiently thin chip, this cutter is not suitable for diffusion work in Louisiana.

THE HUGHES CUTTER.

The system of cutting cane used at Colonel Cunningham's estate in Texas and in the sorghum houses in Kansas is the invention of H. A. Hughes, of Cape May City, N. J. This cutter consists of a metal cylinder, carrying a number of knives, whose blades project from the circumference of the cylinder in the direction of rotation. The cylinder is rapidly revolved in front of a dead knife set parallel to its face. The cane, previously cut into short pieces, is thrown into a hopper, where it is caught by the knives and carried against the dead knife. A small piece of cane is cut off and carried between the knife and dead knife,

and by the centrifugal force is thrown into a receiver below. This cutter or shredder is always used in connection with an ensilage cutter, which latter furnishes the short pieces of cane.

The rapid advancement of cane diffusion is largely due to Mr. Hughes's successful cutting apparatus.

THE NATIONAL CANE SHREDDER.

Many visitors at Magnolia Plantation this season suggested the adaptation of the cane shredder to the preparation of cane for the battery. This machine has been used several seasons by Governor Warmoth in the shredding of whole cane for the mill. If its work during this time can be taken as a criterion, the shredder could be readily adapted to the requirements of diffusion.

THE DIFFUSION BATTERY.

The diffusion battery was built in 1887 by the Colwell Iron Works of New York. It was enlarged in 1888 by Edwards & Haubtman, of New Orleans, according to the directions of Governor H. C. Warmoth.

In the enlargement of the battery the only changes made were in the length of the cells and calorisators or heaters, and the addition of two new cells. The battery as used the past season consists of fourteen cells arranged in a circle, and charged from a central reservoir by means of a revolving chute.

THE CELLS.

The cells are 11 feet long by 44 inches in diameter. The net cane space is 107 cubic feet. The upper doors are 30 inches in diameter and the net opening at the discharge gate is 44 inches, the full diameter of a cross-section of the cell. The joint between the discharge gate and the bottom of the cell is the ordinary hydraulic closure.

CALORISATORS.

The calorisators (heaters) as originally constructed were 49 inches long and 11 inches in diameter, inside measurements. There were eight copper tubes 49 inches long by 2 inches in diameter in each, giving a heating surface of 17.1 square feet. In enlarging the battery seven tubes 12 by 41 inches were added, giving an additional heating surface of 9.2 square feet, and a total of 26.3 square feet per calorisator. The heating surface was sufficient for the work, but it would have been a wise precaution to have increased it considerably more. The heating surface per cubic foot of cell space is .246 square feet, or nearly 4 cubic feet per square foot of heating surface.

JUICE AND WATER MAINS, ETC.

The juice and water pipes are of cast-iron and have a net diameter of 4 inches. The compressed-air pipes are 1 inches in diameter. The

accumulator for compressed air has 75 cubic feet capacity. A 2-inch main furnishes ample steam for the battery.

METHOD OF REMOVING EXHAUSTED CHIPS.

A circular track under the cells, provided with a flat-car having its axles fixed in the direction of the radii of the circle, served to carry the chip car from cell to cell. The flat-car was fitted with a piece of track of the same gauge as that of the permanent railroad leading to the river. When a cell of exhausted chips was discharged into the car the flat-car was drawn by a mule to a point opposite the main line and the chip car run off and taken to the river to be emptied. The round trip required less than seven minutes. A large flat-boat projecting into the river served to carry the track far enough out for the current to wash the chips away.

CRITICISMS ON THE DIFFUSION MACHINERY.

The question of arrangement of a diffusion battery will generally depend upon local conditions. The batteries built for this Department previous to that at Magnolia were of the type known as line batteries. The circular arrangement was selected for Magnolia in order to give the planters an additional example of the different types of diffusion batteries. The circular arrangement has many advantages. It also has disadvantages with which the line battery is not compelled to contend. The principal of these latter is the difficulty attendant upon the removal of the exhausted chips. A builder of this class of machinery informs me that there is no difficulty in arranging to move the chip car from cell to cell by power and finally run it outside the building for dumping.

A circular battery possesses decided advantages over all other forms in ease and regularity of charging the cells with cane chips, neatness of arrangement, and facility of controlling the work. The valves should be so arranged that they can be manipulated from inside the circle. The measuring tank should also be placed inside the circle, preferably at the center.

DEFECTS IN THE MAGNOLIA BATTERY.

The defects in the battery are not due to the workmanship, but rather to the designers and to oversights when increasing its capacity. The Department is in no respect responsible for these latter.

THE CHIP CHUTE.

The chute should be entirely supported from above, a counterpoise relieving the strain caused by the weight of the chute coming entirely on one side. Instead of a sliding door, to block the flow of chips when moving from one cell to another, the end of the chute should be provided with a hinged spout, balanced in such a manner that it can be thrown

back and stop the flow of chips, the bottom of the spout becoming a gate. An illustration of such a chute is given on Plate 1, Bulletin 5, of this division. When this arrangement is adopted there is ample room to place the measuring tank in the center of the upper platform. The valves and pipe-lines being on the inside of the circle, the battery man has easy control of the work, and can not be pardoned for overheating the cells or making other errors.

In the enlargement of the battery the size of the pipe-lines was not proportionately increased. We found for rapid work-i. e., a cell every seven and one-half minutes-that a pipe area of 12 inches is not quite sufficient, but I believe 20 inches would be ample for a cell of the dimensions of those at Magnolia.

The calorisators or heaters were of sufficient capacity. In enlarg ing the calorisators, the original outlets for water of condensation were retained. This oversight caused considerable annoyance, since, owing to the insufficiency of the outlets, several check-valves were broken and the heaters clogged with water.

At present the lower doors of the battery are managed from below by means of a block and tackle. The hydraulic method of opening would have saved considerable annoyance and the labor of one man. A slight change in the position of the drainage-valves will render the work under the battery more comfortable for the laborers and will entail but a small expense.

The hydraulic method of opening large doors is used in a number of places in Europe. In 1882 I visited the works at St. Just, near Cleremont, France, and was much pleased with the management of the large doors of their line battery by this method.

GENERAL REMARKS ON DIFFUSION BATTERIES AND THEIR ARRANGEMENT.

As I have previously stated, local conditions largely control the arrangement of a battery. A single line requires a very long building, but ease of removal of the exhausted chips and favorable conditions for enlarging the plant make this arrangement of the cells a favorite one. The great length of the return pipes is objectionable. The double line also facilitates the use of a simple method of removal of exhausted chips. The return pipes are very short and the manipulations are as simple as in the circular battery. In both the single and double line batteries there is difficulty in charging the last cell in the series with cane without either having chips left over, which fall on the floor, or giving this cell an irregular supply.

The circular arrangement of a battery requires a very high square building. The more complicated method of removing the exhausted chips and the space occupied are the principal objections to this form of battery. The cost of construction varies but little in the different forms of batteries.