The present invention relates to an improved graphite container, in particular for the production of ingots, even more in particular for the production of ingots of precious metal.

In the following disclosure, and in the claims the term "container" and the term "ingot mould" will be equally used, referring to the same element, unless otherwise indicated.

Still more in detail, the invention refers to a container or ingot mould of the type used for processes wherein it is foreseen to insert inside the container a metal in the form of powders, grit or scraps in general, above which a lid is placed, for introducing the container with the metal and the lid into a furnace wherein the metal is melted.

One first container or ingot mould useful for this type of process is disclosed in Patent EP 2730349. The inside of the container provides enough space to receive the amount of metal, in any form, necessary to obtain the ingot, and to allow the lower part of the lid to enter inside the container itself, resting on the mass of metal until it becomes solid.

The lid is superiorly provided with an enlarged edge, such that when the metal has melted, the edge abuts against the outer surface of the container, stopping its descent.

This solution has a main disadvantage due to the fact that the edge of the lid outside the container increases its size in height, so that furnaces with correspondingly greater heights are required, which results in greater energy wastes and greater size of the overall apparatus. Another drawback of the solution disclosed in EP'349 is due to the fact that the internal part of the container has substantially vertical walls, such that inserting and pressing downwards the mass of metal are indeed more difficult.

One first solution alternative to the one disclosed in EP'349 was proposed in the Italian Patent no. 102012902088415, filed on 1st October 2012.

In this patent, which relates to a "graphite container with lid" consisting of two parts (claim 1), it is disclosed in any case an embodiment of the container or ingot mould, with particular reference to figures 6 and 7. In particular, it is mentioned that the lid of the container is bulky. In this case the internal cavity of the container has inclined walls, and the lid is not provided with the upper plate.

Therefore, the lid, once all the mass of the metal has been melted, is located inside the container, not representing any further bulk externally.

Furthermore, the smooth inclined walls of the internal cavity allow to better convey the mass of metal both during the insertion and during the melting. In the same Patent reference is made to the fact that, to obtain an optimal product, when the melting of the metal is complete, the lower wall of the lid must be distant from the upper surface of the melted mass of a distance "s". In the solution that does not foresee the upper plate, the coupling between the internal cavity and the lid, both made of graphite, occurs with the surfaces one against the other, and the blocking of the lid in its downward stroke is simply based on the precision of the processing and on the friction between the two surfaces. The solution of IT'415, despite being able to solve some of the problems of the document previously mentioned, also has some drawbacks, mainly due to the fact that a very high precision is required in the processing of the graphite elements constituting the ingot mould, and to the fact that, over time, mainly due to the high temperatures it is submitted to, graphite "wears out" so that the minimum distance "s" is no longer fulfilled, requiring the replacement of the ingot mould more often than normally needed.

The International Patent Application W02015/149930, despite having a different object, discloses a container or ingot mould which constitutes an improvement with respect to the above-mentioned documents.

The internal cavity of the container has a first upper part with vertical walls, and a final part with inclined walls, connected by an intermediate zone with inclined walls, with a (greater) different angle than that of the walls of the final part.

The lid is substantially parallelepiped-shaped, with a step in its lower part, so that it is inserted in the internal cavity, resting on the intermediate transition zone, when the metal is melted.

This solution has however the same problems of the IT'415 solution, as a great precision in processing the various components is required, without overcoming the problem of the graphite wearing out when the lid is inserted into and removed from the container at high temperatures. The same type of solution is shown in the Italian Patent no. 102014902258434.

In light of the above, it is well apparent the need of a container or ingot mould, suitable for processing in any type of furnace, which is capable of solving the above-mentioned problems.

These and other results are obtained with the improved graphite container or ingot mould, in particular for the production of ingots, even more preferably for the production of ingots of precious metal according to the enclosed claim 1.

Further features and details of the solution according to the invention are described in the dependent claims. The present invention will now be described, by way of a non-limiting illustrative example, according to preferred embodiments thereof, with reference to the figures in the attached drawings, wherein: figure 1 is a perspective view of an open graphite container according to the invention; figure 2 is a longitudinal section view of the graphite container of figure 1; figure 3 is a cross section view of the graphite container of figure 1; figure 4 is a front view of the lid of the graphite container of figure 1; figure 5 is a perspective view of the body of the graphite container of figure 1; figure 6 is a longitudinal section view of the body of the graphite container of figure 1; and figure 7 is a perspective view of the closed graphite container of figure 1.

Referring to the figures of the enclosed drawings, reference number 100 generally denotes the graphite container or ingot mould according to the invention, which provides a body 1 and a lid 2.

The body 1 is substantially parallelepiped-shaped, with an upper opening 11, for receiving the mass of metal to be melted (not shown) and therefore the lid 2.

The lid 2 has a plate 21, having a shape and dimensions as to be perfectly inserted through the opening 11 of the body 1, and a shaped part 22 at the bottom, which will be described hereinafter in greater detail. Observing in detail figures 2 - 6 of the enclosed drawings, it can be observed that the body 1 has an internal cavity which has at the bottom a first part 12 with walls 13 having a first inclination, a second part 14, having inclined walls 15, connected to the inclined walls 13, however with an inclination greater than the one of an imaginary vertical axis, and thus vertical walls 16, which connect to the vertical walls 17 of a third part 18, larger than said second part 14, and which ends with the opening 11. The connection between the second part 14 and the third part 18 of the body 1 constitutes a shoulder 19.

The lid 2 has, as said, a plate 21, which perfectly fits in said opening 11, and a shaped part 22, but with a lower height, so that it leaves a space s between the ingot obtained and the lower part of the lid 1.

In particular, said shaped part 22 has a first lower inclined part 23, and a second upper part 24 with vertical walls, which connects to said plate 21, said lower 22 and upper parts 24 being perfectly complimentary with the shape of the second part 14 of the body 1.

Furthermore, the width of the plate 21 of the lid 2 rests perfectly, once the metal that will be placed inside the container 100 is melted, on said shoulder 19.

The shoulder 19 is rounded or flared to prevent pieces or quantities of metal from stopping near the sharp edge, an event which could compromise the positioning of the lid itself.

Above said lid 2 they are provided means 25 for gripping the lid, which are not an integral part of the solution according to the present invention, and which will not be described in greater detail. Obviously, the lid 2 will be preferably manufactured in a single piece.

Therefore, the container or ingot mould 100 according to the invention allows to:

- insert the metal, in any form, into the internal cavity of the body 1;

- place the lid 2 on the mass of material;

- melt the material;

- have a pressure by gravity of the lid 1 on the material while it is being melted; - have the lid 2, once the melting is complete, stopped by abutment coupling of the plate 21 of the lid 2 with the shoulder 19, thus avoiding rubbing, and consequent wear of the two graphite elements;

- have an optimal sealing due to the shape of the part 22 of the lid 2 and of the second part 14 of the lid 1;

- have the lid 2 stopped at a pre-established distance from the bath of melted metal, to obtain an optimal ingot 101; - ensure a longer service life of the container or ingot mould, maintaining optimal performance.

The present invention has been described for illustrative, non-limiting purposes, with particular reference to preferred embodiments thereof, but it is understood that variations and/or modifications may be made by a person skilled in the art, without departing from the relative scope of protection, as defined in the appended claims.