CLAY-WORKING MACHINERY, ma chines designed for the proper preparation of clay which is subsequently used in the manu facture of bricks, tiles, pipes, etc., in the produc tion of which the importance of the proper preparation of the clay can scarcely be over estimated. A great many of the subsequent difficulties, imperfections and the amount of waste product in the manufacture of articles from clay may be traced directly to the absence of proper treatment of the clay prior to its use in the molding machines. Among the principal machines of this class are the bevel-geared clay granulator and feeder, designed to work on a horizontal plane and reduce plastic, lumpy clay into a mass of uniform texture, before it is fed into the crushing machines. It consists of a tub the sides of which may be made either flared or vertical, within which is rotated a main shaft of large diameter, carrying forged steel knives. These machines are frequently used to feed into disintegrators, or some form of crushing rolls used for fine grinding, afford ing the advantage of having such crushers fed uniformly instead of being alternately over loaded or empty. The double shaft clay feeder and mixer (Figs. 1 and 2) is designed for preparing and feeding plastic clay. As a feeder it forms the bottom of a clay storage bin and will discharge the material at a uniform rate determined by the speed at which the pulley is driven, by the pitch at which the knives are set and by the position of the adjustable gate which regulates the final control. It may also be used to advantage as a double shaft pug mill, in which case the clay bin and the gate are omitted. The standard machine is bevel geared with the driving pulley on the right-hand side as shown in the illustration. Driving pul ley may be placed on the left-hand side if desired. The machine may also be built spur geared. The standard machine discharges the material at the end of the mixing chamber opposite the driving gears, but the machine may be built so as to discharge the material between the mixing. chamber and the gear frame.
. The mixing and pugging machine is de signed to mix two or more ingredients, or dry and wet materials, and to deliver a thoroughly mixed, well-pugged mass, in uniform quantity. It is especially valuable as a mixer of ((grog)) or ground calcined material with plastic clay, ground shale with tough clays, and other finely ground or granular material with plastic binders.
Fig. 3 shows an all-iron and steel dry pan, which is probably the most useful machine for grinding shale, such as is generally used in the manufacture of street paving bricks, and in fact all. of the ordinary brick clays when dried sufficiently to pass through a screen. The machine consists essentially of a pair of heavy iron rollers which rotate vertically and grind against an iron disc of sectional plates rotating horizontally. In the machine illustrated, the grinding rollers are 48 inches in diameter by 10 inches face, their combined weight together with that of their shafts and boxes being about 13,000 pounds. The plows or scrapers run close to the screens and are so constructed that the portions subject to wear are easily and cheaply renewable. The capacity of this ma chine depends entirely upon the nature of the material ground and the amount of moisture contained in that material and the size and pat tern of the screen openings. The total weight of the machine is about 30,000 pounds, and it is fitted with a friction-clutch pulley 48 x 12 inches.
A type of wet pan especially valuable as a mixing and clay preparing machine is shown in Fig. 4. It is a thorough pugger and mixer for all kinds of clay. The mullers or grinding rollers have hard chilled faces, are 48 inches in diameter, with 7-inch faces. This machine is now generally supplied with a mechanical unloader for emptying the batch mechanically. Fig. 5 shows a form of the clay
disintegrators employed to work plastic days in which stone and gravel are embedded. It consists of two rollers, one of which is driven at a high rate of speed (700 revolutions per minute) while the other is run at a rate varying from 50 to 100 revolutions per minute and acts merely as a feed roll. The fast running roll is equipped with steel bars which project slightly beyond its face and act with a cutting action against lumps of strong, tough clays, and also throw out the larger stones against which they come in contact, while the pebbles are crushed and ground up with the clay. It has a broad, heavy iron bedplate. The parting strain between the two cylinders is borne by two heavy through-bolts which pass from one journal box to the other and also enable the regulation of the space between the rolls, varying the capacity of the machine and the degree of fineness of the ground material. Compound day crushing rolls are made in a great variety of patterns. The machine illustrated in Fig. 6 combines the features of a disintegrator and a smooth roll crusher and is especially useful for the worlcing of clays that require an extra amount of prep aration. The upper section is made of two rolls running at variable speed. Similar to that of the disintegrator, the small or high speed roll has projecting blades of hardened sted. The large roll operates at a slower speed. The effect of the combined motions of these rolls is to shred or separate the material and prepare it for the further action of the lower section, which is composed of two large chilled-face rolls for finer grinding. The lower rolls may be adjusted close to each other and thus act as fine grinders of the material partially pre pared by the upper set. The hollow-ware machine shown in Fig. 7 is particularly adapted for the manufacture of all kinds of hollow ware, such as fireproof partitions, and a great variety of other shapes from plastic ma terial. There has been continuous progress in hollow-ware machines, due to increased use of hollow brick for partition walls. Sewer-pipe delivered in predetermined quantity in an even, constant flow. Since about 1905 there has been great improvement in methods of transportation about clay properties. Steam, electric and gasoline locomotives are employed to handle light tram-cars. A great variety of dryer cars are built, with single, double and triple decks. An increasing number are made with steel decks, upper decks being often made to fold or slide away. Other machinery used in clay working, such as conveyors, steam shovels, kilns, pyrometers, etc., will be found described under those titles.
manufacture in the United States increased about 60 per cent in the period between 1904 and 1916, and there was a corresponding in crease in the making of drain tile machines. Flower pot machinery has also come into con siderable use. A variety of drying systems have been developed for hastening the drying of the clay in manufacture. One of these is the rotary clay dryer, having a cylinder of large diameter, heated by a furnace. Clay feeders are made to supply material properly mixed to hollow-ware machines and the like. The clay plow and gatherer is a machine for taking clay from the surface of a field. There are several types of cutting machines on the market for separating the clay into bricks or paving blocks. A reciprocating automatic cutter is made, principally for severing paving blocks, and is adapted to repressed blocks or wire cut lug pavers. The rotary automatic cutter is largely employed for brick work. The poin dometer is a machine for measuring materials at the same time that it automatically tempers the clay. All material is weighed, measured and