The present invention refers to a mechano-chemical reactor where the kinetic energy milling means is used to submit substances in the solid and/or liquid state, loaded into a restricted environment, to a treatment able to modify their physical or chemical characteristics.
The utilization of so-called high energy mills is widespread, the mills making use of a kinetic energy of the milling means usually exceeding 400 W/dm3 with the purpose of subjecting substances in the solid and/or liquid state to physical or chemical-physical treatments.
Primarily, though not exclusively, high energy mills are utilized in the nanotechnologies, namely in the production of nanomaterials which are at least partly formed by particles or granules typically of a size lower than 100 nanometer, namely lower than 10−7 meter. The article by J. Sidor, Mechanical Devices for Production of metallic, ceramic-metallic alloys or nano-materials, published in the Archives of Metallurgy and Materials of the Polish Academy of Sciences, no. 3/2007, is a synthetic presentation of several devices already utilized. As it can be ascertained from the data reproduced in some tables of this article, many of the present high energy mills have a low productivity so that their utilization other than in research laboratories or for a small industrial production (pilot production) is not suitable.
On the contrary, a high energy mill expressly designed for a high productivity (obviously at the date of the corresponding invention, that is according to the evaluations currently made in the early 90's) is disclosed in EP-A-0 665 770, the contents of which is herein incorporated for reference due to the fact that the author of the present invention was also one of the inventors of the mentioned patent. For the same reason, also herein incorporated for reference are the contents of EP-A-0 850 700 and EP-A-1 873 190 where several uses of said mill which, in the latter case, is a true reactor since it produces a treatment which is not only physical but also chemical.
Thus EP-A-0 665 770, which is deemed as the closest prior art of the present invention, discloses a high energy mill comprising a substantially cylindrical milling jar which, after being loaded with heavy balls or other grinding bodies and with a batch of the substances to be treated, is subjected by driving means to an alternate motion, namely to oscillations, along an axis corresponding substantially to the geometrical axis of the jar. When the mill is in operation, an elastic system provides a compensation of the inertial forces which are generated during the oscillations and have a sinusoidal-like behaviour.
In the cited prior art document only a few teachings are provided about the construction of the mill, anyhow from the description and the annexed drawings of the preferred embodiment it can be understood that the elastic system consists of a pair of cylindrical springs, namely of three dimension elements, which are in contact with the upper base and the lower base of the milling jar, respectively. The outer diameter of the springs does not substantially exceed the outer transversal dimensions of the jar, comprising the cooling mantle system. In order to increase the productivity the mill can adopt, instead of a single jar, multiple jars, i.e. constrained each other. Another document belonging to the state of art is CN 2 877 852 Y.
Practical experience has shown that the commercial demand of nanomaterials which is continuously increasing quantitatively as well as qualitatively, cannot be technically and economically met by high energy mills as disclosed in EP-A-0 665 770.
Then, a first object of the present invention is to disclose a true mechano-chemical reactor which, when utilized in the nanotechnologies, is able to produce nanomaterials having chemical and chemical-physical properties modified with respect to the substances (raw materials) subject to treatment, such as: the state of chemical combination of the elements, the state of aggregation and the size of the crystals (when the substances are inorganic), the alloying and solid solution states, the mixing states of the different phases.
Another object of the invention is to disclose a reactor where the elastic system, adopted for the compensation of at least a share of inertial forces generated by the oscillating mass, is of a particularly robust and reliable design.
A further object is to disclose a reactor which, in at least an embodiment thereof, is able to be operated in a continuous mode, namely is able not only to treat the raw materials in separate batches but also able to operate in a continuous mode, i.e. able to treat indefinite amounts of substances in the solid and/or liquid state, thus attaining a very high productivity.
An additional object is to disclose a mechano-chemical reactor which is suitable for utilization in different industrial fields than nanotechnologies, for example in the general field of mixing and grinding various substances, in the chemical and metallurgical syntheses, in the production of liquids, even of a high viscosity with dispersions.
To reach the aims the subject of the present invention is a mechanical-chemical reactor comprising a mass oscillating substantially along one axis thanks to reciprocating driving means, the reactor being able to treat solid and/or liquid substances through the kinetic energy of milling bodies according to the features of the appended claims.
The novel features listed herebelow are deemed of a premium importance:
In the context of the present patent specification (description and claims) the expression “one dimensional or two dimensional” shall not be read in strictly geometrical terms but shall be considered as “prevailingly” one dimensional or two dimensional, i.e. “one dimensional” meaning that one dimension exceeds largely (by a factor of at least 2) the other two dimensions and, respectively, “two dimensional” meaning that two dimensions exceeds largely (each one by a factor of at least 1.5) the other dimension.
For a better explanation of the features and the advantages of the present invention, the following description is of a few non limiting embodiments to which the attached drawings are referred:
b is shows a portion of
A first embodiment of the present invention, illustrated in
The structural frame 40 of the reactor comprises a first rigid pedestal 42, onto which the stationary components of a driving unit 30 are mounted, and a second rigid pedestal 46 resting on the floor through a plurality of spacing feet 48. A plurality of damping devices 44 are arranged between the pedestals 42 and 46. The supporting frame 40 also comprises a first pair 45A and a second pair 45B of columns, the latter being higher than the former. All the columns are projecting vertically from the first pedestal 42 to which are firmly fixed.
The simple jar 10, making part of the oscillating mass described in detail herebelow, is made of a wear resisting steel, e.g. Hardox®, and has the shape of a flattened cylinder with the axis Z arranged vertically and an enlarged basis 16. The introduction of the substances to be treated into the jar 10 and the discharge of the products resulting from the treatment take place through a pair of ports 12A and 12B respectively which are equipped with hermetic valves so as to make the jar a single restricted environment when the reactor is operated. A pair of parallel protrusions 66, 68 provided with coaxial holes (not shown) project downwards from the basis 16 of the jar 10. It is intended that the jar can also be of a non cylindrical shape but in any case its axis of oscillation Z is arranged vertically.
The jar is optionally equipped with ancillary devices such as heat exchangers, vacuum pumps etc, as well as with control devices, e.g. temperature and pressure sensors and vibration sensors (all the said devices being of a conventional construction, so they do not need to be here described in detail nor shown in the drawings). In this manner the treatment by the reactor of the substances loaded into the jar in the desired environmental conditions is ensured at the best.
Also loaded into the jar, with the substances to be treated, is a convenient amount of milling balls 14 (or milling bodies of a different shape) which are made of a material having a high resistance to corrosion and wear, e.g. chromium steel.
The reciprocating driving unit 30 is arranged along a horizontal axis X perpendicular to the axis of oscillation Z of the jar and comprises: a rotary electric motor 32—as shown by arrow F2 in FIG. 1—secured to the first pedestal 42. Through an elastic joint 31B rotor 32 drives an eccentric shaft 34, supported by a pair of bearings 33A and 33B, where the big end 36 of a connecting rod 35 is mounted. The small end 37 of the rod 35 is secured to the basis 16 of the jar 10 through a pin 38 passing through the coaxial holes of protrusions 66 and 68.
For this reason the jar 10, in the case equipped with the above mentioned ancillary and control devices and after it is loaded with the substances to be treated and with the milling bodies, with the small end 37 of the rod 35, are the parts of the entity which is defined as oscillating mass in the present text.
To ensure the start the motor 32 the driving unit 30 comprises a mechanical device 39 supported by the first pedestal 42 of the supporting frame 40 and connected to the shaft 34 through a second elastic joint 31A. The starting device 39 is of a conventional construction, thus it is not deemed as necessary to illustrate its details which include a hydraulic ram for the actuation of a rack coupled to a cogged wheel. Therefore, of the oscillating mass of the reactor, which in this first embodiment is of about 200 to 700 kg, make part the milling jar 10, including the above mentioned small end 37 of the rod 35. The oscillations, namely the reciprocating motion to which the jar 10 is subjected by the driving means, take place in the direction of the axis Z of the jar 10, as shown by the double arrow F1 in
According to the present invention, the elastic system which is able to compensate a majority share (at least 70%) of the inertial forces comprise a plurality of one dimensional or two dimensional flexible elements which, in the rest condition of the reactor, are extended perpendicular to the vertical direction Z of the reciprocating motion of the oscillating mass.
The one dimensional flexible elements are a plurality (for example ten) rectilinear flexible bars 52 made of a titanium alloy. In this first embodiment, as illustrated in
As shown in
At their end portions (respectively at the right and at the left in
In the same manner, another pair of pins 76, in the present context defined as second pins, are protruding from the heads of the second rigid block 73 along the axis Xa. The pins 76 are housed in an end of two arms 78 tilting on a vertical plane. At the second end of the tilting arms 78 are provided another pair of pins which are housed in corresponding bearings 79 secured to the top of the other pair of columns 45A which are comprised in the supporting frame of the reactor, at the left side in
It shall be considered that in
A variant (not illustrated in the drawings since it is easy to realize by a person skilled in the art on the basis of the preceding description) of this first embodiment comprises the utilization, instead of the rectilinear bars, of at least one flexible plate of a polygonal shape, namely at least one two dimensional element, in the construction of the elastic system of the reactor. In the rest condition of the reactor the at least one plate is extended perpendicular to the vertical direction Z of the reciprocating motion of the oscillating mass. A plurality of bolts, or equivalent fastening means, are provided at the central portion of the flexible plate to obtain a rigid connection of the elastic system to the base of the oscillating milling jar while hinging means are provided at two other portions of the flexible plate corresponding to a pair of parallel sides, namely at a pair of locations spaced apart from one another and also spaced from the central portion of the plate. The purpose of said hinging means is to ensure a hinging connection of the elastic system to the structural frame along a pair of axes parallel to the axis X of the driving unit.
Thanks to the above described features, when the reactor is in operation, the one dimensional (bars) respectively two dimensional (plate or plates) flexible elements of the elastic system are able to compensate a majority share of the inertial forces generated by the reciprocating movement of the oscillating mass and having a sinusoidal-like behaviour.
The vibrations of the reactor in its entirety, as well as a minority share of the inertial forces generated by the oscillating mass, are on the contrary scaricate toward the floor through the supporting frame, more precisely through the damping means 44 which are interposed between he first pedestal 42 and the second pedestal of the structural frame.
While leaving unchanged the other features which were described in the preceding pages, instead of the single jar 10 the reactor can comprise what has above been called multiple jar, designated as a whole by the reference numeral 80 comprising a plurality of restricted environments where milling bodies 89 and solid and/or liquid substances to be treated are loaded—see
Also the multiple jar 80, which is made of a wear resistant steel, e.g. Hardox®, is of a cylindrical shape. It comprises: an upper base 84; a lower base 85, wider than the upper base 84; a cylindrical casing, welded to bases 84 and 85, formed by an outer wall 81 and an inner wall 82 thinner than the outer wall; a centrally aligned hub 83, which is in the form of a hollow cylinder welded to bases 84 and 85.
The walls 81 and 82 of the casing are separated from one another by two hollow spaces 94 and 95, each of them being half-cylindrical in shape, where a heating and/or cooling fluid is circulated. Inlet fittings 96A, 96B and outlet fittings 97A, 97B are provided on the hollow spaces for the purpose of filling and draining the fluid—see
As already mentioned here above, while the single jar 10 illustrated in
It shall be understood that a multiple jar can also be of a non cylindrical shape and constructed in such a way to be subdivided into other than four chambers, for example made of materials with a high strength and a low specific weight or made of materials with a honeycomb structure. Thus a multiple jar may comprise five or more chambers or even only two or three chambers.
Each chamber of the multiple jar 80 is provided with two ports, for the inlet respectively outlet and with tubular fittings associated to valves in order to obtain various series and/or parallel connections between the chambers, consequently with different modes of operating the reactor as it will be explained here below.
A first mode of operation of the reactor is, so to say, 100% parallel and is realized when either said tubular fittings are missing or the mentioned valves are only open for the time needed to introduce into the jar the substances to be treated and the time needed for discharging from the jar the products resulting from the treatment. In this case each one of the chambers 90 to 93 is an independent restricted environment where the mechano-chemical processes are separated from one another although simultaneous. As a result the reactor is operated by batches, i.e. in a discontinuous mode, as in the preceding case of the single jar.
A second mode of operation of the multiple jar 80 is, so to say, 100% series with the result that the reactor is operated in a continuous mode.
Of course a batch of substances to be treated can be replaced by a second batch as soon as the treatment in a chamber of the multiple jar is completed with the result of a continuous mode of operation of the reactor. (This mode of operation is feasible also when a single jar 10 is comprised in the reactor by means of a suitable control of the valves 12A and 12B.) Furthermore it is possible to treat the substances only in a few of the chambers of a multiple jar 80, for example treating a first pair of substances α and β in chambers 90 and 91, connected in series and simultaneously treating a second pair of substances λ, and μ in chambers 92 and 93. In this case the second port 114 of the chamber 91 is connected via a tubular fitting 115 to a storage container of the product resulting from the treatment of substances α and β while the second port 109 of the chamber 93 is connected to a storage container of the product resulting from the treatment of substances λ, and μ. It is understood that also other series-parallel operations of the multiple jar 80 are feasible through a proper control of the described tubular fittings and the associated valves.
The mechano-chemical treatments of the substances by the reactor can be controlled either manually or automatically on the base of inputs supplied by sensing means or other monitoring systems of the temperature and pressure conditions in the chambers of the multiple jar 80 in order to act on the heating and/or cooling fluid circulated in the hollow spaces 94, 95 as well as on the state of the valve means associated to the jar.
In order to emphasize the definitely high productivity of the above described first embodiment of the invention, the following table compares the characteristics of a prototype reactor according to the present invention (in the variant comprising a multiple jar 80 according to
A second embodiment of the present invention is now described with reference to
In this embodiment the structural frame comprises the following parts, as can be seen in
The driving means of the present embodiment consist in a pair of driving units 350 and 400, identical one another. For simplicity the first driving unit is described in detail since the construction of their components are illustrated in
The first driving unit 350 (400) comprises a hydraulic motor 351 (401) for the actuation, through an elastic joint 356, a crankshaft 352 (402) extended along a horizontal axis Y1 (Y2) and housed in the parallelepiped box 290, where it is supported by two end bearings 353, 354 and by a central bearing 355. As above mentioned the box 290 is firmly sustained by the upper converging portions 195, 196 of the pillars making part of the structural frame of the reactor. It is noteworthy that the axis Y1 and Y2 of the crankshafts 352 and 402 are parallel and define horizontal plane.
On the cranks of the crankshafts 352 (402) which are closer to the motor 351 (401) are mounted the big ends 364 (414) and 366 (416) of a first pair of opposed rods 360 (410) and 362 (412) while on the cranks beyond the central bearings are mounted the big ends 374 (424) and 376 (426) of a second pair of opposed rods 370 (420) and 372 (422). From associated slots provided at the upper face of box 290 are protruding the small end 367 (417) and a portion of the stem of the rod 362 (412) as well as the small end 375 (425) and a portion of the stem of the rod 370 (420) of said first pair of opposed rods. In a similar manner from associated slots provided at the lower face of box 290 are protruding the small end 369 (419) and a portion of the stem of the other rod 360 (410) as well as the small end 377 (427) and a portion of the stelo of the other rod 372 (422) of said second pair of opposed rods.
The oscillating mass is now described which, as above mentioned, is subdivided into two functional units 250 and 300. In
The functional unit 250 is positioned below the box 290, namely above the horizontal plane defined by the axis Y1 and Y2 of the crankshaft 352 and 452 of the driving means, thus functional unit 250 is called upper functional unit. The functional unit 300 is positioned below the box 290, namely below the said horizontal plane, thus the functional unit 300 is called lower functional unit.
Units 250 and 300 are formed of the same parts though in a different arrangement as it can be appreciated in
Unit 250 (300) comprises a set of three milling jars superimposed one another and bearing top down with reference numerals 252 (306), 254 (304), 256 (302). These are single jars like those above described of the first embodiment and each jar is a restricted environment loaded with the solid and/or liquid to be treated and the balls or other milling bodies 89.
In each set the jars are constrained each other by clamps (not shown) which also ensure the fastening of the set to a parallelepiped box 258 (308) which is provided with slots at one of their horizontal faces lying perpendicular to axis Z. In the box are housed a first and a second axle 260 (310) and 262 (312) extended along the axes Y3 (Y5) and Y4 (Y6) which are parallel to the axis Y1 and Y2 of crankshafts 352 and 402 respectively and define a horizontal plane.
In the upper functional unit 250 the box 258 is fixed at the bottom of the set of jars 252, 254, 256 which means that the said slots are provided at the lower face of the box 258, facing the box 290 where the crankshafts 352 and 402 are housed. In the lower functional unit 300 the box 308 is fixed at the top of the set of jars 306, 304, 302 which means that the said slots are provided at the upper face of the box 258, facing the box 290 where the crankshafts 352 and 402 are housed. This is the different arrangement of the parts in the two functional units which has been already mentioned here above.
At first, let us consider the connections involving the first driving unit 350 or, more precisely, the crankshaft thereof 352.
The small end 367 of a rod 360 belonging to the first pair of opposed rods (namely those which are close to the motor 351) is mounted onto the second axle 262 in the box 258 of the upper functional unit 250 while the small end 369 of the second rod 362 in the same pair of rods is mounted onto the first axle 310 in the box 308 of the lower functional unit 300.
The small end 375 of a rod 370 belonging to the second pair of opposed rods (namely those which distant from the motor 351) is mounted onto the first axle 260 in the box 258 of the upper functional unit 250 while the small end 377 of the second rod 372 in the same pair of rods is mounted onto the second axle 312 in the box 308 of the lower functional unit 300.
As regards the connections involving the second driving unit 400 or, more precisely, the crankshaft thereof 402, the small end 417 of a rod 410 belonging to the first pair of opposed rods (namely those which are close to the motor 401) is mounted onto the second axle 262 in the box 258 of the upper functional unit 250 while the small end 419 of the second rod 412 in the same pair of rods is mounted onto the first axle 310 in the box 308 of the lower functional unit 300.
The small end 425 of a rod 420 belonging to the second pair of opposed rods (namely those which distant from the motor 401) is mounted onto the first axle 260 in the box 258 of the upper functional unit 250 while the small end 427 of the second rod 422 in the same pair of rods is mounted onto the second axle 312 in the box 308 of the lower functional unit 300.
To sum up, the second embodiment of the opposed two by two, being mounted onto each crankshaft and ensuring the connections with the two sets of milling jars of which the oscillating mass is formed. Thence, the two sets of milling jars are simultaneously subjected by both crankshafts to reciprocating movements in counterphase along the same vertical axis Z by means of the opposed rods.
As in the first embodiment the expressions vertical axis of the reciprocating movements and perpendicularity between said axes and the axes of the driving means shall be understood with some tolerance, indicatively in the order of 5 mm.
As above anticipated, it is the described architecture of the connections that contributes, in a dynamic form, to the compensation of the inertial forces generated by the oscillating mass.
In order to ensure that the reciprocating movements take place simultaneously and in counterphase, two systems are provided in the reactor.
The first system (not illustrated in the drawings for simplicity and also for the reason it can be easily realized by a person skilled in the art) acts directly on the driving means and consists of four synchronizing gears. One gear is keyed on each crankshaft 352, 402 while the remaining two gears are in mesh with one another.
The second system comprises four identical articulated parallelograms. For simplicity the following description refers to the parallelogram 480 which is shown in
Parallelogram 480 comprises a lever 482 having a central fulcrum 484 positioned onto the box 290 housing the crankshafts 352 and 402 of the driving units 350 and 400. At the ends 481 and 483 of the lever 480 are hinged the first ends of respective arms 486 and 488. Arm 486 has its second end 487 hinged onto the box 258 comprised in the first functional unit 250 while arm 488 has its second end 489 hinged onto the box 308 comprised in the second functional unit 300.
Also in the second embodiment an important share of the inertial forces generated by the reciprocating movements of the oscillating mass is compensated by an elastic system comprising one dimensional or two dimensional flexible elements.
In the example illustrated in
Each elastic subsystem comprises four pairs of flexible rectilinear bars which, when the reactor is in rest conditions, are extended substantially perpendicular to the direction of the oscillations (reciprocating movements) of the functional units 250 and 300, namely substantially perpendicular to axis Z. Of the said four pairs of rods only two are shown in
In consideration that all flexible bars are identical and that in each pair the bars are vertically spaced from one another, the following detailed description is uniquely referred to
At the proximal ends thereof hinging means 536, 538 are provided for the connection of flexible bars 532, 534 to the box 258 making part of the upper functional unit 250 of the oscillating mass. The axes Y7, Y8 of hinging means 536, 538 are perpendicular to axis Z of the reciprocating movements of the oscillating mass, that is horizontal.
On the contrary the distal ends 540, 542 of the same flexible bars 532, 534 are fixed by means of stud bolts rigidly, namely are rigidly fastened, to an upper portion of the support in the form of a column 545 which makes part of the structural frame of the reactor, at the right side of the vertical axis Z.
This construction is the same as regards the pair of flexible bars 582, 584 belonging to the lower elastic subsystem, also at the right side of the vertical axis Z of the reciprocating movements of the oscillating mass, with the difference that the proximal ends of the bars 582, 584 are connected through hinging means to the box 308 making part of the lower functional unit 300 of the oscillating mass and the distal ends are fixed by means of stud bolts, namely are rigidly fastened, to a lower portion of the support in the form of a column 545 which makes part of the structural frame of the reactor.
Totally in symmetry with the above description, the flexible bars disposed in the reactor at the left side of the axis Z of the reciprocating movements of the oscillating mass are connected at their proximal ends by hinging mean to the box 258 of the functional unit 250 and are fixed by means of stud bolts to the support in the form of a column 541 which makes part of the structural frame.
As a completion of the description of the second embodiment, the following details are added with reference to
In the following Table 2 are the characteristics, referred to the discontinuous mode of operation, of a prototype mechano-chemical reactor in accordance with the second embodiment of the present invention.
Without coming out of the field of protection ensured by the appended claims, on the base of the teachings given in the preceding description at least the following variants of the second embodiment of the reactor are deemed as feasible:
Number | Date | Country | Kind |
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TV2010A000168 | Dec 2010 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB2011/055708 | 12/15/2011 | WO | 00 | 6/21/2013 |