Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/326

282 away. In another machine, also with revolving table, two moulds receive the charge of clay at once. While these are being filled the two that had just been filled are being subjected to considerable pressure, and the two bricks that had been pressed immediately before are in process of delivery out of the moulds, and on to a flat belt which takes them away. (This machine is also suitable for dry clay.) In yet another, a cylinder revolving under the pug-mill presents to it successively four brick-moulds, each of which, on reaching the lowest point, is made to deposit its brick on an endless band. The annexed drawing represents one of Messrs H. Clayton, Son, & Hewlett s single delivery machines for brickmaking with plastic clay. After what has been said little description will be neces sary. A is the pair of rollers, B the pug-mill, C the stream of issuing clay, which a little further on is cut across by means of the wire frame D. The bricks are then removed to the barrow E. These machines are often constructed for double delivery.    Fid. 2. Brickmaking Machine for Plastic Clay.    Fig. 3. Section of Machine for Non-plastic Material. FIG. 4. Part of Machine shown in section in fig. 3. As an example of the second class of machines, those for working dry, or half-dry, and non-plastic material, we may take another machine constructed by Messrs Clayton. It affords a good practical solution of the problem of making bricks from coal shale, bind, fire-clay, or the like. The arrangement is shown in figs. 3 and 4. In fig. 3, A is a pan roller mill, in which a pan containing the raw material is driven round under rollers ; there are perfora tions in the bottom, through which the ground clay escapes, and is swept by arms into a general receiver, whence a band with buckets conveys it to the hopper of the mould ing and pressing machines C, of which fig. 4 gives another view. Here the moulds are contained in a box at B, bolted between the standards. There are two sets of pistons, one above and the other below the brick-moulds, and they simultaneously press the top and the bottom of the brick in the mould. The lower pistons are attached to a cross bar which slides in vertical guides in the standards, and has friction rollers C on the lower extremities, in con tact with which work two pressing cams D on the main shaft. The upper pistons E are attached as shown to a cross-head above, which is moved up and down in its guides by connecting rods and two cranks on the main shaft. These pistons are hollow, and are heated by steam to prevent the brick-earth adhering to them. The prepared material is supplied to the two moulds by a feed-box which slides to and fro under the feeding hopper of the machine, 