WO2010116059A1

WO2010116059A1 - Induction hot press

Info

Publication number: WO2010116059A1
Application number: PCT/FR2010/000292
Authority: WO
Inventors: Jean-Luc Mossotti
Original assignee: Jean-Luc Mossotti
Priority date: 2009-04-09
Filing date: 2010-04-07
Publication date: 2010-10-14
Also published as: EP2416951A1; FR2944225A1

Abstract

The invention relates to the use of a hot press in which the heating means (25) is an induction device arranged around the heating/compression chamber (21). The press can advantageously also include a compression chamber (210) arranged on the closed side of the heating/compression chamber (21), and a precompression chamber (28) arranged on the open side of the heating/compression chamber (21). Said use is particularly suitable for compacting steel fibres from the recycling of used tyres.

Description

INDUCTION HEATING PRESS

The invention is in the field of packaging materials. More particularly, the invention is in the field of the compaction of metal fibers, particularly steel fibers and more particularly steel fibers from the recovery of used tires.

By metal fibers is meant in this text ferrous or non-ferrous metal fibers. Currently, used tires are valued by two methods

- grinding using rotary shears to reduce the tires in small pieces (cheap) about 10 cm x 10 cm, so as to bake in cement; - Passing these small pieces (cheap) in die presses that make it possible to obtain three mixed fractions o rubber powder o textile fibers o and flakes of steel. These three fractions are then separated.

It is to this third fraction generally consisting of an extremely resistant steel and of high quality that interest the invention.

In the process of upgrading tires, the passage of

"cheap" in die presses leads to obtaining, after separation, flakes of steels still rich in textile and rubber fibers closely related to the steel itself. Various methods are then used to clean these fibers to obtain a mass of pure steel (ie without textile fiber or rubber) to something between 90 and 100%. For example, processes based on extremely fine shearing of steel fibers may be mentioned.

However, once the fibers obtained in a state of purity compatible with recycling steelmaking it is still necessary to condition them to be acceptable by the steel mills. In general they are packaged in the form of calibrated ingots obtained by compaction of fibers in a press.

But the metal fibers generally have a clean elasticity, sufficient to not retain the shape that gives them the presses, particularly cold presses, generally used.

Hot presses were used. In these presses the fibers are heated while being forced by the press.

Various means of heating the fibers have been described as direct heating of the fibers or conductive heating through the mold of the press itself heated.

These nevertheless effective means are unsatisfactory because of their small diameter fibers undergo undesired transformation during heating and compression is not facilitated.

There is therefore a need for new presses for compressing metal fibers, particularly steel fibers, particularly steel fibers derived from the upgrading of tires, without the constraints and inconveniences of the presses currently used.

It is an object of the invention to provide such a press.

Thus the invention relates to a heating press characterized in that the heating is obtained by induction. Such a press is able to compress the metal fibers while heating them without contact with the heating means, to make ingots used in foundry.

The subject of the invention is also a heating press comprising at least one induction heating means for use in compacting metal fibers, particularly steel fibers and even more particularly steel fibers resulting from the recovery of used tires. .

Induction heating is a heating technique based on electromagnetic induction. A magnetic field applied to an object made of conductive material induces electrical currents within said object, thereby causing it to overheat. It is thus produced a so-called inductive heat. Its advantage is to heat materials without contact with the energy source. This technique allows: • to regulate the heat to diffuse accurately.

• heat faster an object because the heat is transmitted much faster along ^the object that ^a traditional heat by convection;

• an economy of ^space, the heat being generated in the material itself which results in little thermal radiation;

• working possibilities without dirt or smoke;

• a much higher profitability, conditioned by a lower heat loss and ^emission. The basic components of an induction heating system are an alternating current generator, an inductor and a room (material to be heated or treated). The generator passes an alternating current through the inductor, which generates a magnetic field. When the part is placed in the inductor, the magnetic field induces eddy currents, generating precise amounts of clean and localized heat, without any physical contact between the inductor and the part.

The principle of induction makes a relation between the frequency of the alternating current and the depth to which it enters the room; low frequencies between 5 and 30kHz are effective for thick materials that require deep heat penetration, while higher frequencies between 100 and 40OkHz are effective for smaller parts or for low penetration. The higher the frequency, the higher the heat flow.

In addition, the non-conductive materials have the advantage of allowing magnetic fields induced by the inductor to pass without their modified heat being seen. Thus it is possible to exploit this property to form molds in which the part to be heated can be introduced, molds through which it can be induced a magnetic field using an inductor. Thus only the room will be heated. The invention thus has for its main object a heating press characterized in that it comprises at least one induction heating means.

According to a first embodiment of the invention, the subject of the invention is an induction heating press comprising at least one heating / compression chamber that can be made of a non-conductive material, itself possibly comprising at least one side wall. closed and a bottom, said mold chamber in which slides a piston, which itself can be made of the same material as the heating / compression chamber and induction heating means of the material introduced into the heating / compression chamber, said heating means being positionable out of contact with the material to be heated, for example outside or inside the walls of said mold. Advantageously according to this first embodiment, the bottom of the heating / compression chamber of the press can be movable to facilitate the ejection of the final metal ingot obtained after heating and compression.

According to the invention, the heating / compression chamber can take any desired shape. Preferably, the heating / compression chamber may have a cubic, parallelepipedal or cylindrical shape. Preferably, the heating / compression chamber may have a parallelepipedal shape.

According to the invention, the heating / compression chamber can take all the desired dimensions. Advantageously, the heating / compression chamber may have an internal length of between 0.5 and 5 meters, preferably between 1 and 3 meters.

Similarly, the heating / compression chamber may have an inner section of square or parallelepiped shape, the sides of which may have internal dimensions, identical or different, between 0.2 and 2 meters, preferably between 0.5 and 1 meter . When the section will be circular, then the internal diameter of the section may be between 0.2 and 2 meters, preferably between 0.5 and 1 meter. According to the invention, the heating / compression chamber may be any non-conductive material, such as for example ceramic, glass, quartz, wood, granite. Preferably, it will be possible according to the invention to use a granite heating / compression chamber. The thickness of the walls and the bottom of said heating / compression chamber may be a function of the material used and the person skilled in the art will readily be able to adapt it to the nature of said material and to the resistance necessary to withstand the pressure induced by the piston. For example when said chamber is granite, the thickness of its walls may be between 5 mm and 200 mm, preferably between 10 mm and 100 mm.

According to the invention, the induction heating means can take all known forms. For example it may be a solenoid disposed around the heating / compression chamber. The induction solenoid may cover part or all of the outer wall of the heating / compression chamber. Advantageously, the solenoid may cover the entire outer wall of the heating / compression chamber.

In this first embodiment of the invention, the process for preparing the metal ingots may proceed as follows: in a first step, the piston being positioned outside the heating / compression chamber, it is introduced the interior of the metal to be compressed, advantageously so that it occupies the entire volume of said chamber;

In a second step, the inductive solenoid induces a magnetic field sufficient to induce heating of the metal contained in the heating / compression chamber and the metal is compressed using the piston for a sufficient time. so that all the metal is compressed;

In a third step, the magnetic field is stopped, the piston is withdrawn and the compressed metal ingot is recovered.

It is understood from the foregoing that in this first embodiment of the invention, the size of the final ingot will be small compared to the size of the heating / compression chamber. For this reason, in a second embodiment, the invention may further comprise a precompression chamber, advantageously disposed on the open side of the heating / compression chamber, in continuity with said heating / compression chamber, said chamber precompression may have a section at least identical to the section of said heating / compression chamber and a length that the skilled person can easily adapt to his needs. The usefulness of such a pre-compression chamber is to be able to load a quantity of metal to compress sufficiently large so that at the end of the compression cycle the ingot obtained has dimensions approximately equal to the internal dimensions of the heating chamber. compression. Thus advantageously, said precompression chamber may have at least internal dimensions identical to the internal dimensions of the heating / compression chamber.

According to this second embodiment of the invention, the precompression chamber may be in any material compatible with its function. In particular this chamber may not be of non-conductive material. Advantageously, it may be steel. In this second embodiment of the invention, the method for preparing the metal ingots may be identical to that implemented with the first embodiment of the invention, with the difference that in the first step of the method, may introduce the metal to be compressed inside the precompression chamber and the heating / compression chamber, advantageously so that it occupies the entire volume of said chambers.

According to a third embodiment, the invention may further comprise a compression chamber, disposed on the closed side of the heating / compression chamber, in continuity with said heating / compression chamber but beyond the bottom of said chamber, said compression chamber may further comprise a bottom, advantageously mobile, disposed opposite the bottom of the heating / compression chamber, said compression chamber being able to present a section identical to the section of said heating / compression chamber and a length that the skilled person can easily adapt to his needs.

According to this third embodiment of the invention, the compression chamber may be in any material compatible with its function. In particular this chamber may not be of non-conductive material. Advantageously, it may be steel.

In this third embodiment of the invention, the method for preparing the metal ingots may be identical to that implemented with the first embodiment of the invention, with the difference that in the third step, stops the magnetic field, opens the movable bottom of the heating / compression chamber and the piston is pushed with the ingot into the compression chamber where the compression will continue for a time sufficient for all the metal to be compressed and in a fourth step the piston is removed and the compressed metal ingot is recovered.

It is understood that whatever the embodiment of the invention, additional advantages will arise from the fact that on the one hand the bottom of the heating / compression chamber and / or the bottom of the compression chamber may (may) be mobile (s) since it will facilitate the recovery of the ingot after compression, for example by simply pushing the piston, and that secondly, the press according to the invention can be used in a vertical position, the piston can be at the top and the movable bottom of the heating / compression chamber and / or possibly that of the compression chamber may be opposite to said piston relative to the device constituted by the press according to the invention.

Advantageously according to the invention, the bottoms of the heating / compression and / or compression chambers may be movable and the press may be used in a vertical position. Whatever the embodiment of the invention, its use for compacting the metal fibers can be carried out according to a method in which in a first step, said metal fibers are introduced into an induction press as described above;

In a second step, said metal fibers are compressed while heating them by means of the induction heating device of said press;

In a third step, after stopping the heating, an ingot of compressed metal fibers is recovered.

Those skilled in the art will readily understand that in order to be used in a vertical position, the press according to the invention must not rest on the ground and that it must be secured to a support frame that it will easily adapt to the constraints of using the press.

According to the invention the presses according to the second and third embodiments will be preferred.

Whatever the embodiment chosen, the piston may induce a pressure which may be between 100 kg and 30 tonnes, preferably between 500 kg and 10 tonnes.

The invention also relates to the use of an induction press as described above for the compaction of metal fibers.

The invention is particularly well suited to the compaction of steel fibers from the recovery of used tires.

Other advantages, aims and features may be apparent from the following description, made for the purpose of explaining and in no way limiting, the appended drawings in which:

Figure 1 shows a sectional view of a press according to the first embodiment of the invention, positioned vertically on a support.

Figure 2 shows a sectional view of a press according to the second embodiment of the invention, positioned vertically on a support.

Figure 3 shows a sectional view of a press according to the third embodiment of the invention, positioned vertically on a support.

FIG. 4 represents the steps of the metal fiber compression process, carried out with a press according to the second embodiment of the invention. Thus, with reference to FIG. 1, a first embodiment of the invention is observed in which a press according to the invention (A) can be seen, comprising a heating / compression chamber (1), itself comprising closed sidewalls of non-conductive material (2), a removable bottom (3), a piston (4) and an induction solenoid (5) surrounding said chamber. According to the representation, the heating / compression chamber (1) is filled with metal fibers (6) to be compressed. The entire press is in a vertical position with the piston at the top and is fixed to a support (7) (attachment not shown). With reference to FIG. 2, a second embodiment of the invention is seen in which a press according to the invention (A) can be seen, comprising a heating / compression chamber (11), itself having walls. closed sides of non-conductive material (12), a removable bottom (13), a piston (14) and an induction solenoid (15) surrounding said chamber and a precompression chamber (18) itself including closed side walls (19). According to the representation, the heating / compression chamber (11) and the precompression chamber are filled with metal fibers (16) to be compressed. The entire press is in a vertical position with the piston at the top and is attached to a support (17).

With reference to FIG. 3, a third embodiment of the invention is seen in which a press according to the invention (A) can be seen, comprising a heating / compression chamber (21), itself having walls. closed sides of non-conductive material (22), a removable bottom (23), a piston (24) and an induction solenoid (25) surrounding said chamber, a precompression chamber (28) itself including closed side walls (29) and a compression chamber (210) itself including closed side walls (211) and a removable bottom (212). According to the representation, the heating / compression chamber (21) and the precompression chamber are filled with metal fibers (26) to be compressed. The entire press is in a vertical position with the piston at the top and is attached to a support (27). Referring to Figure 4, there is shown in 4 steps a metal fiber compression cycle performed with a press according to the second embodiment of the invention (see Figure 2).

In step (A), the piston is removed to the maximum thereby opening the press so that the metal fibers are introduced into it.

In step B, the solenoid is subjected to an alternating current and a magnetic field is created in the metal fibers causing their heating. At the same time the piston is actuated to compress the heated fibers. In step C, the alternating current is cut off, no magnetic field occurs in the press because the fibers are sufficiently compressed by the piston. The removable bottom is in the process of opening.

In step D, the removable bottom is completely open and the piston ejects the ingot of compressed fibers.

Claims

Claim 1.) Use of a heating press comprising at least one induction heating means for compacting metal fibers.

2.) Use according to claim 1, characterized in that the press comprises at least

a mold-forming heating / compression chamber made of a non-conductive material, said chamber comprising a closed side wall and a bottom, in which a piston slides, advantageously itself made of the same material as the heating / compression chamber; and

- An induction heating means of the material introduced into the heating / compression chamber, said heating means being advantageously positioned out of contact with the material to be heated, for example outside or inside the walls of said mold.

3.) Use according to any one of claims 1 or 2, characterized in that the bottom of the heating / compression chamber of the press is movable.

4.) Use according to any one of claims 1 to 3, characterized in that the heating / compression chamber of the press is non-conductive material, such as ceramic, glass, quartz, wood, granite , preferably granite.

5.) Use according to any one of claims 1 to 4, characterized in that the induction heating means of the press is a solenoid disposed around the heating / compression chamber.

6.) Use according to any one of claims 1 to 5, characterized in that the press further comprises a precompression chamber advantageously disposed on the open side of the heating / compression chamber.

7.) Use according to any one of claims 1 to 6, characterized in that the press further comprises a compression chamber, disposed on the closed side of the chamber of heating / compression, in continuity with said heating / compression chamber but beyond the bottom of said chamber.

8.) Use according to claim 7, characterized in that the compression chamber further comprises a bottom, preferably movable, disposed opposite the bottom of the heating / compression chamber.

9.) Use according to any one of claims 6 to 8, characterized in that the precompression chamber and / or the compression chamber is a conductive or non-conductive material, preferably steel.

10.) Use according to any one of claims 1 to 9 for compacting steel fibers, particularly steel fibers from the recovery of used tires.

11.) Method of compaction of metal fibers, characterized in that - in a first step said metal fibers are introduced into an induction press as described in any one of claims 1 to 10;