COMBINED MACHINE FOR THE THERMIC DRYING TREATMENT OF DIELECTRIC PRODUCTS

Abstract

A combined machine for the thermic drying treatment of dielectric products includes a box-like casing which defines a process chamber or cavity configured to receive a dielectric product placed on support means and to be thermally treated to obtain the drying thereof. A pumping means is operatively connected to the box-like casing and configured to be operated to create vacuum conditions inside the process chamber or cavity in the presence of the dielectric product. In particular, the combined machine includes an electric generator configured to generate a radio frequency output signal, at the desired output power, and applicator means, contained in the process chamber or cavity and electrically connected with the electric generator, configured to develop an electromagnetic field at a treatment zone of the dielectric product defined in the process chamber or cavity for heating the dielectric product itself.

Claims

1. A combined machine for the thermic drying treatment of dielectric products comprising: box-like casing which defines a process chamber or cavity suitable for receiving a dielectric product placed on support means and to be thermally treated to obtain its drying; pumping means operatively connected with said box-like casing and suitable to be operated to create vacuum conditions inside said process chamber or cavity in the presence of said dielectric product, characterized in that it comprises an electric generator for generating a radio frequency output signal, at a desired output power, and applicator means, contained in said process chamber or cavity and electrically connected with said electric generator, suitable to develop an electromagnetic field at a treatment zone of said dielectric product defined in said process chamber or cavity for heating said dielectric product.

2. The machine according to claim 1), wherein said electric generator includes a generation unit of radiofrequency signals at a first power level and amplification means, electrically connected with said generation unit, suitable for amplifying said radiofrequency signals of said generation unit from said first power level to said output power.

3. The machine according to claim 2, wherein said amplification means comprise one or more amplification stages, each of which includes an active solid state electronic component.

4. The machine according to claim 3, wherein said active solid state electronic component is of the semiconductor type.

5. The machine according to claim 1, wherein said radiofrequency output signal has a frequency of value comprised in the range 300 Khz+300 MHz, preferably equal to 13.56 MHz or equal to 27.12 MHz or equal to 40.68 MHz.

6. The machine according to claim 2, wherein said generation unit of radiofrequency signals at a first power level comprises a high voltage oscillating/resonant circuit

7. The machine according to claim 1, wherein said applicator means comprise a pair of polarity-opposed electrodes facing each other, arranged one with respect to the other according to a prefixed configuration.

8. The machine according to claim 7, wherein said prefixed configuration is of the type in which said polarity-opposed electrodes are facing and parallelly spaced apart each other in such a way that: said treatment zone is comprised between said electrodes suitable to be arranged at two opposite sides of said dielectric product, with the positive electrode placed at a first side of said dielectric product and the negative electrode placed at a second side of said dielectric product; said electromagnetic field generated by said electrodes is predominantly orthogonal to said dielectric product.

9. The machine according to claim 7, wherein said prefixed configuration is of the type in which said polarity-opposed electrodes are facing and parallelly spaced apart each other in such a way that: said treatment zone is arranged above or below both said electrodes suitable to be arranged at only one side of said dielectric product; said electromagnetic field generated by said electrodes is predominantly tangential to said dielectric product.

10. The machine according to claim 7, wherein each of said electrodes is composed of a plurality of consecutive electrodes, each of which has the same polarity or opposite polarity with respect to the adjacent electrode to it.

11. The machine according to claim 7, wherein said electrodes comprise components distinct from said box-like casing.

12. The machine according to claim 7, wherein said electrodes comprise two opposite portions of the internal wall of said box-like casing.

13. The machine according to claim 1, wherein it comprises a capacitor interposed between said pumping means and said box-like casing.

14. The machine according to claim 1, wherein it comprises detection means of the temperature and/or humidity present in said process chamber or cavity, operatively connected with said box-like casing and suitable to adjust the input power of said radiofrequency electric generator and/or the level of said vacuum conditions in said process chamber or cavity.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0031] FIG. 1 is a schematic view of a combined machine for the thermic drying treatment of dielectric products (e.g., animal hides from the tanning industry, foodstuffs such as milk or polymers in granular or flake form and the like).

DETAILED DESCRIPTION

[0032] As can be seen, the combined machine 1 for the thermic drying treatment of dielectric products, indicated with D in the attached FIG. 1, comprises: [0033] a box-like casing 2, made of any material compatible with its intended use, which defines a process chamber or cavity 3 immersed in air and adapted to accommodate the dielectric product D, such as an animal hide or a foodstuff, placed on support means (not shown for the sake of convenience and comprising, for example, a conveyor belt) and to be heat-treated to dry it; pumping means, indicated as a whole by reference numeral 4 and typically consisting of a vacuum pump, operationally (i.e., hydraulically) connected to the box-like housing 2 and adapted to be operated or activated to create conditions of vacuum inside the process chamber or cavity 3 in the presence of the dielectric product D.

[0034] According to the invention, the combined machine 1 includes an electric generator 5 which generates a radio frequency output signal, at the desired output power, and applicator means, indicated as a whole by reference numeral 6, contained in the process chamber or cavity 3 and electrically connected to the aforesaid electric generator 5; these applicators develop an electromagnetic field at a defined treatment zone 7 of the dielectric product D within the process chamber or cavity 3 to heat the dielectric product D itself.

[0035] In particular, the electric generator 5 includes a unit for the generation of radio frequency signals at a first power level, and amplification means, electrically connected to the generation unit, adapted to amplify said radio frequency signals of the generation unit from the first power level to the output power.

[0036] Preferably but not necessarily albeit advantageously, the amplification means comprise one or more amplification stages, each of which includes an active solid-state electronic component. This allows a significant reduction of the size of the electric generator, and more generally of the combined machine of the invention.

[0037] Even more preferably, the solid-state active electronic component of the amplification stages is of the silicon or gallium nitride semiconductor type.

[0038] As known, a solid-state generator is a generator which uses a means of energy gain but has no movable parts. By way of example, semiconductor generators—a particular type of thermoelectric generator—are a typical example of a solid-state generator.

[0039] The radio frequency output signal has a frequency of value comprised in the 300 Khz-300 MHz range, preferably equal to 13.56 MHz or equal to 27.12 MHz or equal to 40.68 MHz.

[0040] In further executive variants of the combined machine of the invention, not shown below, the radio frequency signal generation unit at a first power level may include a high voltage oscillating/resonant circuit (e.g., a triode).

[0041] According to the preferred embodiment of the invention described herein, the applicators 6 comprise a pair of opposing polarity electrodes 8, 9 facing each other, mutually arranged according to a preset configuration, chosen as desired by the manufacturer or according to the customer's needs.

[0042] In this case, the predetermined configuration is of the type in which said opposite polarity electrodes 8, 9 face each other, are parallel and spaced apart in such a way that: [0043] the treatment zone 7 is comprised between the electrodes 8, 9 adapted to be arranged at two opposite sides of the dielectric product D, with the positive electrode placed at a first side of the dielectric product D and the negative electrode placed at a second side of the dielectric product D, in general opposite to the first side; [0044] the electromagnetic field generated by the electrodes 8, 9 is predominantly orthogonal to the dielectric product D which is transiting (if placed on a conveyor belt) or fixed in the treatment zone 7.

[0045] In other construction solutions of the combined machine of the invention, not accompanied by reference drawings, the predetermined configuration taken by the electrodes is of the type in which such opposite polarity electrodes face each other and are parallel to each other so that: [0046] the treatment zone is arranged above or below both the electrodes adapted to be arranged at only one side of the dielectric product to be treated; [0047] the electromagnetic field generated by the electrodes is mainly tangential to the dielectric product to be treated.

[0048] In a preferred but not binding manner, each of the electrodes 8, 9 is composed of a plurality of consecutive electrodes, each of which has the same polarity (in the case of electromagnetic field predominantly orthogonal to the dielectric product D) or opposite polarity (in the case of electromagnetic field predominantly tangential or parallel to the dielectric product) with respect to the electrode aligned and adjacent thereto (e.g. in a direction parallel to the feeding direction of the dielectric product on the movable support means).

[0049] This constructional expedient, due in practice to the breakdown of each of the general electrodes 8, 9 into a plurality of sub-electrodes (or elementary electrodes), allows the combined machine 1 of the invention to obtain, on the one hand, non-trivial and non-negligible operational advantages (during operation), such as, for example, a greater uniformity in the heating treatment of the dielectric product D, and a punctual, selective and diversified heating of the dielectric product D.

[0050] On the other hand, such a breakdown of the electrodes 8, 9 into a plurality of elementary electrodes allows achieving equally important management advantages (during the possible and inevitable, at least periodic and scheduled downtimes), such as, for example, greater simplicity in the maintenance, repair and/or replacement of the electrodes which can thus be localized and limited to the single elementary electrode(s) and not concern the entire component, to the advantage of the associated costs.

[0051] These operational and management advantages are in no manner reflected in the available prior art, not even in the prior document published under number DE3521061 A1.

[0052] As can be seen in FIG. 1, the electrodes 8, 9 (which can take any spatial arrangement in the process chamber or cavity 3) comprise separate components of the box-like casing 2.

[0053] It is understood that in alternative embodiments of the combined machine of the present invention, not shown in the accompanying drawings, the electrodes may comprise two opposite portions (uniform or monolithic or divided into separate pieces placed side-by-side) of the inner wall of the box-like casing.

[0054] The combined machine 1 of the instant invention also comprises a capacitor 10 interposed between the pumping means 4 and the box-like housing: the function of the capacitor 10 is to condense the vapor in excess with respect to the capacity of the pumping means 4 (such as the mentioned vacuum pump).

[0055] Preferably but not exclusively, although appropriately, the combined machine 1 of the present invention comprises detecting means (not shown for the sake of simplicity but of the type known to the person skilled in the art) of the temperature and/or humidity present in the process chamber or cavity 3, operationally connected to the box-like casing 2 and adapted to adjust the input power of the radio frequency electric generator 5 and/or the level of the vacuum conditions in the process chamber or cavity 3 generated by the pumping means 4.

[0056] By virtue of the aforesaid description, it is thus apparent that the combined machine for the thermic drying treatment of dielectric products according to the present invention achieves the purposes and reaches the advantages yet mentioned.

[0057] Upon implementation, modifications could be made to the combined machine for the thermic drying treatment of dielectric products of the invention, e.g., consisting of pumping means of a different type from the one mentioned in the preceding part of the description, provided they are adapted to create and maintain the vacuum conditions of (in which pressure is lower than atmospheric pressure).

[0058] Additionally, further construction solutions of the combined machine for the thermic drying treatment of dielectric products claimed herein exclusively, not illustrated in the attached figures, may provide that the electric generator has a different construction concept from the preferred one described above, which does not impair the advantage brought by this invention.

[0059] Finally, it is apparent that many other variants may be made to the combined machine for the thermic drying treatment of products concerned electromechanical device, without departing from the principles of novelty inherent in the inventive idea, just as it is apparent that in the practical implementation of the invention, the materials, shapes, and sizes of the details shown may be any according to the requirements and may be replaced by other technically equivalent elements. Where the constructional features and techniques mentioned in any successive claims are followed by references signs or numerals, such reference signs were introduced for the sole purpose of increasing intelligibility of the claims themselves, and therefore such reference signs have no limiting effect on the interpretation of each element identified by way of example only by such reference signs.