The sugar from which the cubes are made is of a rather fine grain, boiled in special pans from liquor that has been filtered over the char at least twice. From the centrifugals under the pan it falls into a hopper in which there is a revolving screw. Directly over the screw is a tank containing a warm, white sugar liquor, very sticky and viscous by reason of its density. A pipe leads from the bottom of this tank to a point over the screw, and the liquor, which is controlled by a valve, is allowed to drip upon the sugar. The action of the screw causes the sugar and the liquor to become thoroughly mixed and feeds the damp mass thus formed into a spout leading to the cube press, the machine in which cube sugar is made.
At the top of this machine is another hopper, into which the damp sugar drops from the spout overhead, and revolving in the last-mentioned hopper are a number of small shafts with brass pegs inserted at certain intervals along the length of the shafts, like spokes in the hub of a wheel. These pegs are like human fingers in their action and they press the sugar down into the pockets of a large revolving drum placed directly under the hopper. Each pocket is the size of a cube or half cube. Working in these pockets are plungers, which fall back as the revolving drum reaches the highest point directly under the mechanical fingers in the hopper. The fingers fill the open pockets and, as the drum turns, the plungers, at a certain point in its circumference where a heavy bronze bar is placed across its face, slowly enter the pockets and in so doing compress the sugar into cube form.
Two belts run through the machine under the cylinder, carrying galvanized iron plates about twenty-four inches wide, or the same width as the cylinder, and thirty inches long. As the line of pockets into which the sugar has been pressed reaches the lowest point on the circumference of the drum, the plungers drop down, forcing the pressed cubes out of the pockets onto the galvanized iron plates which the moving belt carries along out of the way of the next lot coming from the cylinder. Each plate, as it leaves the cube press, contains five hundred and four cubes and one hundred and sixty-eight half cubes, and the time required to fill a plate is between six and seven seconds.
CUBE-SUGAR MACHINE
CARTON MACHINE
The belts carry the plates to a series of ovens, or driers, so placed that a large number of plates with their contents may be inserted through a door on the belt side. When the ovens are filled with plates holding the soft, moist cubes, a current of hot air is turned on at the top of the ovens, passing out at the bottom. The hot air circulating in this manner dries the cubes and carries off the moisture. Eight hours in the ovens suffice to render the cubes thoroughly dry and hard. They are then removed through doors opposite to those through which they were put in. This arrangement prevents the men who are putting the cubes into the ovens from interfering with those taking them out, for the process is a continuous one and cubes are placed in and removed from the ovens at the same time. As the cubes are taken out of the ovens, they are deposited on a belt conveyor which delivers them into bins in the packing room, ready to be put into boxes, bags, barrels and other containers.
POWDERED AND BAR SUGAR
Powdered and bar sugars are made by grinding coarse granulated sugar into fine particles and then separating these particles by screening them through fine silk cloth. The bolting of flour is a similar process. Powdered sugar has a decided tendency to cake and become hard, and the coarse sugar from which it is ground should be particularly free from moisture. After being crushed or ground between corrugated rolls turning at high speed, the ground sugar passes into a screening or sifting device, of which there are many kinds in use, the most common being the horizontal, revolving centrifugal screen. The crushed sugar goes in at the head end, and, as it enters, a number of revolving arms throw it against a silk screen on a circular frame, revolving in an opposite direction, that permits the finest, or powdered, sugar to pass through a silk cloth having over sixteen thousand openings per square inch.