Upon a transverse shaft, c, journaled at the axis of box, B, is set a paddle-wheel composed of a suitable hub, d, and adjustable paddles, each composed of the radial stem, e, and the blade, f, or spoon. The spoons, f are set on the stems, e, so as to be capable of being reversed or turned half-way round, more or less. One side of the spoon, f, is rounded off, so that while passing through the stock the latter will not cling to or remain upon it. The other side of the spoon is flat, but slightly skewed or bevelled, so that when turned to face with the direction of motion of the wheel it not only gathers up the stock and holds it till out of the box, B, but upon further elevation causes it to roll or slide along the paddle to a predetermined point, where it falls off gently into a discharge-spout, g, which carries it off for further treatment practically undamaged. During the operation the box, B, and the body, A, are kept supplied by a stream of clean or chemically-prepared water, and the wheel, e f, revolves slowly in the box, the edges of the paddles sweeping around, while the box, B, or its bottom, is kept oscillating, thus preventing an injurious clogging of the perforations in the box-bottom. After the stock is placed in the box, B, and the latter filled with sufficient water, the wheel, e f, is caused to slowly revolve (by motive or hand power), with the rounded sides of the spoons, f, presented forward. This operation thoroughly agitates and cleanses the stock, while the rounded form of the spoons prevents the breaking up of the natural condition of the stock. The inventor gathers the finer particles as follows, after they have escaped through the perforated bottom of the wash-box, B. At the lower part of the trough, A, elevated on crossbars or blocks, h, he places two parallel strips, i, and between these, which are grooved to form ways, k, inside, is set a long screen, l, placed on rollers, m, and movable thereby on the rails or ways, k. To give movement to the screen, l, the inventor attaches to its end a rod, n, which projects outwardly through the walls, a a, by means of the packing-box, p, and cap or door, q, which, when opened, allows the withdrawal of the screen, l, and its burden. The shaking of the screen is accomplished by a suitable motor applied to rod, n, and is kept going during the operation as required. To the strips, i, which are placed at a little distance from the side walls, a (to leave a passage for the water and refuse to go through), are hinged the two doors, r, which shut down upon the rod, s, as a support, in which case nothing can fall upon the screen, or which open up and rest against the sides, a a, in which case the screen is exposed and the side passages closed by the doors, r. During the initial or rough-washing stage the doors, r, are kept closed, and the dirty water and refuse pass freely down the side passages and out at a suitable opening at the bottom. After this stage it becomes desirable to catch the particles which get detached from the stock in box, B, and come through the perforations therein. Then open up the doors, r, thus closing the side passages and compelling all the water and small stock to go to the screen, l, which catches the remaining stock. When sufficiently accumulated the screen may be drawn out and the stock thereon removed. When the main body of stock in box, B, has been cleansed, the paddles or spoons, f, are reversed, so as to present their flat, skewed faces to the stock, and in revolving the paddles now gently lift the stock and discharge it into the spout or hopper, g. The washing and removal of the stock when washed are thus accomplished without further manipulation than to reverse the paddles, which obviously could be done by a reversing-gear on the motor, thereby reversing the direction of movement of the paddle-wheel.
Instead of the whole box B being oscillated back and forth, its bottom may be set on slides or rollers and oscillated, while the sides remain stationary.
In the drawings the box B is shown as hung upon the shaft c as a centre; but as the provision of means of reciprocating or oscillating the box or its bottom is within the skill of any machinist, it is not necessary to describe any specific form. As the box with its contents will be very heavy, the inventor prefers a special motor for it, which may also be geared up to reciprocate the screen l.
Instead of the door q, as located in Fig. 2, it can be located as at q’, same figure.
The entire plant must of course be arranged according to sanitary regulations, especially as regards river pollution, etc.
The sheds for sorting and storing the glue-stock should, if possible, be in close proximity to the pits and washing drums, and be dry and airy. In arranging his plant, the glue manufacturer must, in short, exercise his ingenuity with a view to carrying on the business with as little loss of material, and as much saving of time and labor as possible.
The work in a factory arranged in the above manner, is carried on as follows:
The raw materials brought by the dealer are weighed, and if in green state, the customary percentage—generally 50 per cent.—taken off. To facilitate future operations, and to enable the manufacturer to produce different varieties of glue, the dry materials are sorted and stored in different compartments of the store-shed.
Green waste, i. e., such as has not been limed must be taken in hand at once, as otherwise it would taint the air, be attacked by rats and other animals, and suffer injurious alterations by decomposition. The manner of operation is as follows:
Liming. Prepare “milk of lime” by filling the pits, which are to serve for the reception of the skin waste, with the required quantity of water and dissolve in it 2 per cent. of calcium hydrate obtained by slaking a good quality of quick lime. Stir thoroughly, and in order that the water may become thoroughly saturated with the lime, let the liquor stand for 8 or 10 days before placing the waste in it. The liquor should stand about 9 inches deep over the waste in the pits. The length of time the waste has to remain in the milk of lime varies according to the material; calf skins requiring 15 to 20 days, sheep skins 20 to 30 days, and heavy ox hides 30 to 40 days. The milk of lime should be renewed once or twice a week, and thoroughly stirred.