Fig. 18.
The beans are first broken into smaller pieces in all machines now employed as crushing, shelling or cleansing apparatus, and the one at present under consideration provides no exception. An air-current is made to play on these fragments, which finally isolates and transfers the loosened shells to another part of the apparatus. The cacao next succeeds to a crusher of regular capacity lodged in the upper part of the machine, being despatched on an elevator. The fragments fall into a cylindrical sieve, dust being detached in the first compartment, whilst the meshes of subsequent compartments gradually increase in size and sort the products therein transmitted in corresponding sizes. There is a groove traversed by air-currents—proceeding from a ventilator—immediately under each compartment. This current of air can be regulated, i. e. made weaker for lighter and stronger for heavier fragments, and there is a ventilator for every compartment to make this regulation of the easiest, and in this way shells of equal size but specifically lighter than, the cacao fragments are most efficaciously separated. Contrasting with the older type of machine, it works almost noiselessly, all shakings of grooves and sieves being entirely avoided; in addition to which there is a perfect exclusion of dust, when the shells are transferred into the dust-removing chamber. A further advantage is that there is no wearing out of the machine, except as regards the direct crushing apparatus, which occasionally need renewing.
The dust particles before mentioned, which possibly comprise as much as one half of the cacao fragments, require a special kind of working up, on different machines, before the cacao still contained therein can be obtained. It is a fact obvious and apparent, that the smaller the fragments of shell mixed with this crushed cacao, the more difficult will be their separation, a fact of equal importance to technical and analytical science, and the more scrupulously this process is to be carried out, the greater the lavishment on sieves and ventilating compartments entailed.
To effect this operation on the breaking machine is seriously to overtask the latter, and defeats its own end, as experiments carried out in the Chocolate factory of Schütte-Felsche have proved, inasmuch as it leads very easily to mixing of the products which are to be kept separate.
Fig. 19 shows such a machine for the cleansing of this so-called cacao “dust
The particles are raised to a large flat sieve by means of an elevator, again sorted in different sizes, and submitted to air currents of corresponding strength. The quantity obtained varies according to the variety of cacao, though in some cases it may amount to 50 or 54 percent. What remains after this process is absolutely worthless and can only be considered as refuse, at least as far as the chocolate manufacturer is concerned.
Fig. 19.
It has become necessary in modern manufacture that iron fragments occurring in the machine not only be separated by distinct magnetic fields in the respective machines, but that this also be effected in a machine specially constructed for the purpose. Fig. 20 illustrates such an electromagnetic apparatus. The advantages of this system are that it avoids magnets limited in strength, and by the functioning of strong electro-magnets perfect cleansing even in the case of the largest output, as well as machines of the most simple construction, can be guaranteed.
We submit the following description of the machine and its method of working.