103
The work of the drum in moving is as follows: The rollers, S S, enter the grooves successively, and are driven forward by their sloping faces. The mould-table stops when the rollers are held in the normal parts of the grooves; it is then held firmly in place by the three rollers, which prevent its movement in either direction.
The skeleton of the apparatus is composed simply of a frame carrying pedestals, of moulding table, of a central guide for the table, pistons, levers, shafts, cranks and winches, the drum and the hydraulic regulator. These are reduced to the most simple form, if we take into consideration the numerous actions they perform.
The moulds are filled by means of an ordinary distributor fed by apparatus for mixing the paste. The finished bricks are thrown on a rocking table, U. or upon an endless band placed directly under the machine.
The spring, r, in Fig. 4, serves to bring the lower arms, L L, back to their original positions, after having aided in partially compressing the mixture.
The mould table carries twelve to fourteen moulds, and the pressure which can be obtained is a little over 4000 pounds to the square inch.
Some of the advantages claimed for this machine are: equal compression on both faces, and consequent homogeneity of composition; perfectly formed briquettes, little liable to loss by breakage in transportation; reduction of the motive power to the minimum; and the possibility of having all the parts of the machine directly in sight, and the consequent care which can be taken of them.
These presses, manufactured in France by Biétrix & Co., and by Schuchterman and Kremer in Germany, have come into very general use.
The Yeadon press, manufactured at Leeds, which is of this same general type, is also in use in many parts of the world.
HYDRAULIC PRESSES.
The Révollier (French) and Bodmer (English) were among the earliest hydraulic presses made, and were very effective, but in the earlier ones the cost of production was slightly higher than in other presses. As a type of this class of presses the following description by Dr. Grimshaw of the improved machine built by the Société Nouvelle des Forges et Chantiers de la Mediterranée is given:
"
"The briquette machine of the 'Société Nouvelle des forges et Chantiers de la Mediterranée' is shown in two sections, in Fig. 1, Plate XV. It is a modification of the Mazeline and Cody compressing machine, well known in Europe in this industry. By the patent office classification it would, as now built, be considered as a duplex hydraulic machine, with horizontal mould tables, continuous moulding and successive production.
"It differs from the old type of machine:
"First. In consisting of two separate machines, which can be worked either or both at will, thus permitting one to work at normal belt speeds on half production.
"Second. In employing hydraulic pressure. Thus, while in the Mazeline machines the compression is by steam pistons acting on a lever, and reaches a maximum of 90 kilogrammes per square centimetre (say 1200 pounds per square inch) of horizontal section of the briquette—it varies in the new machine from 100 to 300 kilogrammes per square centimetre of the same section, and without recourse, as we shall see later, to the special pumps, accumulators, etc., which accompany hydraulic machinery of all kinds.
"This agglomerating machine consists of:
"First. A Mixer (A). This is a large vertical wrought iron cylinder, in which the materials are brought gradually to a temperature suitable for agglomeration. It is composed of a double envelope, in which circulates steam, which keeps the walls at a high temperature. On the same axis, as the cylinder turns continuously, a vertical shaft, armed with blades, aa, which divide the materials, mix them and knead them. Jets of steam are let in at the same time by openings shaped like rose sprinklers, and so placed on the walls as to surround the materials on all sides during the mixing, and to heat them by giving up all the very considerable heat (530 calories). When the material appears sufficiently hot or agglomerant (which the workman can readily see by taking some in a shovel and pressing it with his hands), he opens two doors, bb, in the lower side, and the material falls into the distributing apparatus.
"Second. The Distributor.—This serves to distribute the paste into the moulds. It is composed of a cast iron chamber, in which turns a rake or scraper, of which the arms, c, sweep the material into the moulds, which pass under the distributor, and are there completely and uniformly filled.
"Third. Moulding and Discharging Apparatus.—One on each side of the filler, and under it, are two rotating ' mould tables,' which are heavy disks or plates of cast iron, bearing on their plane faces, near their circumferences, a circle of angular recesses, faced with steel, and corresponding "
Taken from Engineering, November 8, 1878.