阅读说明：本技术 干燥经过预处理的柔性片材产品的设备 (Apparatus for drying pretreated flexible sheet products ) 是由 安东尼奥·波拉托 于 2018-11-30 设计创作，主要内容包括：一种用于干燥经过预处理的柔性片材产品的干燥设备(1),柔性片材产品具有其上预先沉积有化合物层的至少一个面,该系统(1)包括用于在方向(L)上供给片材产品的供给装置(2)、用于随着产品的供给对产品进行干燥的干燥装置(3)以及控制单元(16),所述干燥装置具有至少一个开放的操作单元(5),该操作单元具有腔室(6)和至少一个施加器(10),供给装置(2)被设计为穿过所述腔室,并且所述施加器与相应的发生器(11)相连以施加在RF范围内的交变电磁场,所述控制单元用于控制发生器(11)和/或施加器(10)。所述场的振荡频率在300kHz至300MHz的范围内并且优选为27.12MHz,并且设置了用于输送热空气的至少一个鼓风装置(18)(18)和/或至少一个抽吸装置(19)。控制单元(16)被配置为改变供给装置(2)的速度或改变电磁场施加时间。还设置了传感器装置,用于检测操作单元(5)的一个或多个物理和/或热力学参数以及片材的温度,并且用于彼此独立地或组合地控制装置(2、18、19)并实现化合物层的完全干燥。(Drying apparatus (1) for drying a pre-treated flexible sheet product having at least one face on which a compound layer is pre-deposited, the system (1) comprising a feeding device (2) for feeding the sheet product in a direction (L), a drying device (3) for drying the product as it is fed, and a control unit (16), said drying device having at least one open operating unit (5) having a chamber (6) through which the feeding device (2) is designed to pass and which is connected to a respective generator (11) to apply an alternating electromagnetic field in the RF range, and at least one applicator (10) for controlling the generator (11) and/or the applicator (10), the oscillation frequency of said field being in the range 300kHz to 300MHz and preferably 27.12MHz, and at least one blowing device (18) (18) and/or at least one suction device (19) for feeding hot air being provided, the control unit (16) being configured to change the feeding speed of the device (2) and/or the application speed of the electromagnetic field, and/or the control unit (16) being configured to change the feeding speed of the feeding device (2) and/or the application of the physical sensor (5) and to achieve the application of the drying device, the combination of the drying device, the application of the alternating electromagnetic field, the physical sensor, the application of the physical sensor, the physical sensor (5) and/or the control unit (16.)

1. Drying apparatus (1) for drying a pre-treated flexible sheet product having at least one face on which a layer of a compound has been pre-deposited, the apparatus (1) comprising:

-a feeding device (2) for feeding the sheet product (M) in a longitudinal feeding direction (L);

-a drying device (3) for drying the product as it is fed, said drying device (3) having at least one operating unit (5) having a chamber (6) and at least one applicator (10) therein, said feeding device (2) being designed to pass through said chamber (6) and said applicator (10) being connected to a respective generator (11) to apply an AC electromagnetic field in the RF range to dry the compound deposited on the product during processing;

-at least one control unit (16) for controlling the generator (11) and/or the applicator (10);

characterized in that the oscillation frequency of the AC electromagnetic field is in the range of 300kHz to 300MHz, and preferably 27.12MHz with tolerances within the permitted ISM band, in that at least one blowing device (18) and/or at least one suction device (19) for conveying hot air are provided in the chamber (6), the blowing device (18) being controlled to convey hot air at a predetermined temperature, and the suction device (19) being configured to suck in moisture extracted from the chamber (6) during drying, in that the control unit (16) is configured to vary the speed of the feeding device (2) or to vary the electromagnetic field application time, in that sensor means are provided in the chamber (6) for detecting one or more physical and/or thermodynamic parameters of the at least one operating unit (5), such as the temperature and/or residual humidity in the chamber and the temperature of the hides, respectively, and for controlling the supply device (2), the blowing device (18) and the suction device (19) independently of one another or in combination and for achieving complete drying of the compound layer.

2. The apparatus of claim 1, wherein the electromagnetic field generator (11) is selected from the group consisting of a power transistor, an inverter-controlled power transistor, a modular electronic power amplifier, a converter power amplifier, an amplifier using solid state technology, or a combination thereof.

3. The apparatus according to claim 1, characterized in that the feeding device (2) comprises a belt or wire conveyor (4), wherein the belt or wire is tensioned by end rollers and defines with the top sections of the end rollers a feeding plane (pi).

4. The device according to one or more of claims 2 and 3, characterized in that said applicator (10) comprises at least one series of electrodes arranged in said chamber (6) and connected to a pair of terminals of said generator (11).

5. The apparatus according to claim 4, characterized in that said electrodes comprise at least one pair of substantially parallel plates made of conductive material, respectively having the function of an anode and a cathode for applying said radiofrequency electromagnetic field, said plates being respectively arranged below and above said feeding plane (pi) at an adjustable distance from said feeding plane (pi).

6. The device according to claim 4, characterized in that said electrodes comprise a first and a second transverse series (12, 13) of bars made of electrically conductive material, said first and second series (12, 13) of bars being connected to a first and a second terminal, respectively, of said generator (11), said bars being adapted to be arranged at an adjustable distance from each other.

7. The apparatus according to claim 6, characterized in that the bars of the first series (12) and the bars of the second series (13) are arranged below or above the conveyor (4), the bars of the first series (12) being longitudinally offset from and alternating with the bars of the second series (13).

8. Apparatus according to claim 6, characterized in that the bars of one series (12) are arranged below said feeding plane (π) and the bars of the other series (13) are arranged above said feeding plane (π), at least the bars of said first series (12) being longitudinally offset from and alternating with the bars of said at least one second series (13).

9. The apparatus according to one or more of the preceding claims, characterized in that it comprises a plurality of operating units (5A, 5B, 5C), a plurality of operating units (5A, 5B, 5C) being downstream one from the other in said feeding direction (L).

10. The device according to claim 9, characterized in that each operating unit (5A, 5B, 5C) comprises at least one respective generator (11A, 11B, 11C) and/or at least one respective applicator (10A, 10B, 10C), said at least one respective generator (11A, 11B, 11C) and/or at least one respective applicator (10A, 10B, 10C) being connectable to at least one control unit (16A, 16B, 16C) to generate an electromagnetic field of appropriate intensity in the respective chamber (6A, 6B, 6C).

Technical Field

The present invention finds application in the field of leather manufacture in general and relates in particular to a plant for drying pretreated flexible sheet products, such as industrial hides, skins, artificial leathers or leather derivatives.

Background

Hides, after various tanning, retanning and dyeing treatments, are known to generally present surface defects, which are either naturally formed in the life of the animal (scratches due to stabbing, contact with barbed wire or thorns), or due to poor preservation of the leather after skinning.

In these cases, once the hides are dried, they undergo a surface treatment, commonly known as finishing, whereby these defects are removed or less visible for better use of the hides.

During chemical finishing, the compound, usually in liquid form, is deposited on the hide to form a grain layer that can have different thicknesses or be elastic or flexible, depending on the type of finish and leather.

The compound is initially deposited on the grain side of the hide in a predetermined amount and then dried to form a layer bonded to the fibers to be integrated with the hide.

The finish compound is typically applied by spraying or using a rotating roller that comes into contact with the hide as it is fed.

Furthermore, the compound drying process is typically carried out using an oven or air duct operating using infrared, catalytic gas, and more often hot air.

For this purpose, the plant for the surface treatment of hides comprises one or more drying units to which hot air is fed by means of high-flow compressors and blowers, the flow of which can reach thousands of meters³H is used as the reference value. The drying temperature in these devices is generally from 80 ℃ to 160 ℃.

A first drawback of these plants is that the manufacturing energy costs associated with the high hot air flow rate for drying the hides and the plant operation are very high.

A further disadvantage is that the hides dried as described above have a high surface temperature and are not easy to handle and stack.

Therefore, it is generally possible to cool the completely dried hides using cooling means with high power consumption (e.g. a cold air cooler).

Another disadvantage is that the high temperature drying process is not uniform and tends to change the "hand" of the leather, i.e. to make it harder and less soft than the leather in the raw state.

Finally, any shrinking action of the thermal drying process results in shrinkage of the hide, resulting in a significant reduction in the useful leather area and a reduction in the ultimate intrinsic value of the treated hide.

In an attempt to at least partially eliminate these drawbacks, hide drying plants have been developed that use electromagnetic fields having frequencies in the radio frequency range.

EP2935631, by the owner of the present invention, discloses a plant for drying hides having a pair of operating units comprising respective radio-frequency electromagnetic field applicators located in chambers and connected to respective high-frequency AC voltage generators.

That is, the two operating units are configured to dry the different finishing compounds previously deposited on the hides by the one or more deposition units.

A first disadvantage of this arrangement is that the apparatus does not allow feedback-responsive adjustment of the operation of the generator and applicator in accordance with the operating conditions of the drying unit.

A further disadvantage is that the hides must be subjected to two drying processes to achieve optimum results. This disadvantage involves an increase in the overall processing costs.

Another drawback is that the electrodes are arranged in the drying unit in a traditional geometry, which cannot be changed to optimize the application of the electromagnetic field on the hides as they are fed.

Another disadvantage is that the use of a single radio frequency limits the drying efficiency of the compound and the hides and causes accumulation of residual moisture in the drying unit.

Technical problem

In view of the prior art, the technical problem solved by the present invention is to ensure a combined regulation and control of the various thermal and fluid-dynamic parameters of the equipment to dry the finishing compound efficiently and rapidly after it has been deposited on the product.

Disclosure of Invention

The object of the present invention is to solve the above problems by providing an efficient and relatively cost-effective drying apparatus for drying pretreated flexible sheet products.

It is a particular object of the present invention to provide an apparatus as described above which enables combined and feedback-responsive control and regulation of sheet product drying components.

It is a further object of the present invention to provide an apparatus as defined above which is capable of drying the finishing compound quickly and efficiently, irrespective of the amount of coating compound deposited on the sheet product.

It is a further object of the invention to provide a device as described above which is capable of optimizing the overall energy costs.

It is a further object of the present invention to provide an apparatus as described above which is capable of using a combination of different drying modes.

It is a further object of the present invention to provide an apparatus as described above that is capable of removing residual moisture that accumulates in the drying unit.

It is a further object of the present invention to provide an apparatus as described above which is capable of varying the electromagnetic field applicator to optimize the efficiency of application on the product.

These and other objects, as will be better apparent hereinafter, are achieved by an apparatus for drying a pretreated flexible sheet product as defined in claim 1, wherein the sheet product has at least one face on which a layer of compound has been previously deposited.

The apparatus comprises a feeding device for feeding the sheet product in a longitudinal direction and a drying device for drying the product as it is fed.

The drying device has at least one operating unit with a chamber through which the supply device is designed to pass and at least one applicator in the chamber, which applicator is connected to a corresponding generator to apply an AC electromagnetic field in the RF range to dry the compounds deposited on the product during processing.

The apparatus further comprises at least one control unit for controlling the generator and/or the applicator. The oscillation frequency of the AC electromagnetic field is in the range of 300kHz to 300MHz, and preferably 27.12MHz with a tolerance in the permitted ISM frequency range, and at least one blowing device (18) and/or at least one suction device (19) for conveying hot air are provided.

The blowing means is controlled to deliver hot air at a predetermined temperature and the suction means is configured to suck in moisture extracted from the chamber during the drying process. The control unit is configured to vary the speed of the feeding means or to vary the electromagnetic field application time, and sensor means are provided in the chamber for detecting respectively one or more physical and/or thermodynamic parameters of the at least one operating unit, such as the temperature and/or the residual humidity in the chamber, and the temperature of the hides, and also for controlling the feeding means, the blowing means and the suction means, independently of one another or in combination, to ensure complete drying of the compound layer.

Advantageous embodiments of the invention are defined in the dependent claims.

Drawings

Further features and advantages of the invention will become more apparent upon reading the detailed description of some preferred, non-exclusive embodiments of a plant for drying pretreated flexible sheet elements, such as industrial hides, skins, artificial leathers or leather derivatives, according to the invention, which are described as non-limiting examples with the help of the accompanying drawings, in which:

FIG. 1 is a perspective view of a drying apparatus of the present invention;

FIG. 2 is a side view of the apparatus of FIG. 1;

FIG. 3 is a front view of the apparatus of FIG. 1;

FIG. 4 is a side cross-sectional view of the apparatus of FIG. 1;

fig. 5 is a side cross-sectional view of the apparatus of fig. 4.

Detailed Description

With reference to the above figures, a plant for drying pretreated flexible sheet products, such as industrial hides, skins, artificial leathers or leather derivatives, is shown and is generally designated by the reference numeral 1.

Rawhide is known to comprise grain and flesh sides and has a pre-deposited layer of a finish compound on one of the two sides, preferably on the grain side.

The drying process of the compound carried out by the apparatus 1 of the invention imparts specific aesthetic and tactile properties to the leather.

The finish compound may be deposited by known deposition means, such as spray coating or roller deposition. The latter is configured to deposit a layer of a compound having a surface density of 0.001g/m on at least one face of the sheet product²To 500g/m²Preferably 5g/m²To 150g/m²Within the range of (1).

For example, the deposited compound may serve as a primer, a color coat and a finishing coat, and may be selected from the group consisting of polymeric compounds such as acrylic resins and urethane resins, inorganic compounds such as iron oxides, and pigments and natural compounds.

In a preferred embodiment of the invention, the apparatus 1 comprises a feeding device 2 for feeding sheet products in a longitudinal direction L and a drying device 3 for drying the products as they are fed.

As known per se, the feeding device 2 may comprise an endless belt or wire conveyor 4, wherein the belt or wire is tensioned by end rollers and defines with the top sections of the end rollers a feeding plane pi of the sheet products.

Furthermore, the drying device 3 comprises at least one operating unit 5 having a chamber 6, through which chamber 6 the feeding device 2 passes.

That is, the chamber 6 may be at least partially closed and delimited by a box-like structure 7, which box-like structure 7 has an inlet 8 and an outlet 9 for the passage of the feeding device 2.

As best shown in fig. 4 and 5, the drying chamber 6 comprises at least one applicator 10 therein, which applicator 10 is connected to a high-frequency voltage generator 11 to apply an AC electromagnetic field with an oscillation frequency in the range of 300kHz to 300MHz, so as to dry the compounds deposited on the product during processing, independently of its surface density.

Preferably, the generator 11 is configured such that the value of the oscillation frequency of the electromagnetic field is 27.12MHz within the allowed ISM band with a tolerance.

The electromagnetic field applied to the flexible sheet product being fed in the operating unit 5 may then heat the compound to a predetermined temperature.

The generator 11 may be selected from the group consisting of a power transistor, an inverter controlled power transistor, a modular electronic power amplifier, a converter power amplifier possibly employing solid state technology, or a combination thereof.

The applicator 10 comprises at least one series of electrodes arranged in the drying chamber 6 and connected to a pair of terminals of the generator 11.

In a first embodiment of the invention, not shown, the electrodes may comprise at least one pair of substantially parallel plates made of electrically conductive material, which respectively have the function of an anode and a cathode for applying the radiofrequency electromagnetic field.

Plates may be provided below and above the feed plane pi at adjustable distances to selectively vary the intensity of the electromagnetic field applied to the product during processing.

Alternatively, the electrodes may comprise a first and a second transverse series 12, 13 of bars made of electrically conductive material, connected to a first and a second terminal, respectively, of the generator 11.

The electrodes of one series 12 are connected in parallel and have the function of a cathode, and the electrodes of the other series 13 are also connected in parallel and have the function of an anode.

As mentioned above in relation to the plates, the bars 12, 13 may also be arranged at an adjustable distance, thereby adjusting the electric field strength.

For example, as shown, the bars of the series 12 may be fixed to a longitudinal beam 14 which is moved in the respective vertical direction by suitable driving means 15 to move the first bar towards or away from the bars of the other series 13.

In a second embodiment of the invention, as best shown in fig. 4 and 5, the bars of the first series 12 and the bars of the second series 13 can be arranged below or above the feed plane pi of the conveyor 4.

That is, the bars of the first series 12 may be longitudinally offset from the bars of the second series 13 and alternate with the bars of the second series 13, and each bar of the first series 12 may define, in combination with the adjacent bars of the second series 13, a respective applicator 10.

In a third alternative embodiment, also not shown, the bars of one series 12 can be arranged below the feed plane pi, while the bars of the other series 13 can be arranged above the feed plane pi.

As in the second embodiment, the bars of the first series 12, whether they are arranged below or above the feeding plane, are longitudinally offset from the bars of the second series 13 and alternate with the bars of the second series 13.

Also in this embodiment, each bar of the first series 12, arranged below or above, defines a respective applicator 10 with a bar of the second series 13, arranged above or below and longitudinally offset from the first series.

Furthermore, the apparatus may comprise at least one control unit 16, which control unit 16 is configured to control the generator 11 and/or the applicator 10 and/or the feeding device 2 to completely dry the compound previously deposited on at least one face of the sheet product in the operating unit 5.

For example, the control unit 16 may be configured to set the speed of the supply device 2 to a predetermined value in the range of 0.01m/min to 30m/min, preferably 6m/min to 15m/min, or to change the application time or intensity of the electromagnetic field.

Further, the control unit 16 may include a control algorithm installed therein and a storage section. Which may store data and information corresponding to a plurality of drying programs.

The software may be configured to select the most appropriate drying program depending on the properties of the sheet product to be treated.

In addition, as best shown in fig. 1, the control unit 16 may comprise an interface device 17, which interface device 17 is adapted to be actuated by an operator for managing it.

Advantageously, the operating unit 5 may comprise at least one blowing device 18 and/or at least one suction device 19 in fluid communication with the drying chamber 6.

Air blowing means 18 and suction means 19 may also be connected to the control unit 16 to adjust the drying temperature of the sheet product and further dry the compound.

The blowing means 18 may be controlled to deliver hot air at a predetermined temperature, while the suction means may be configured to suck in moisture removed from the chamber 6 during drying.

A sensor device, not shown, can also be provided in the drying chamber 6, which sensor device is connected to the control unit 16.

The sensor means are configured to detect one or more physical and/or thermodynamic parameters of the operating unit 5, for example the temperature of the chamber and/or the temperature of the hides and/or the residual humidity 6 in the chamber 6.

Furthermore, the control unit 16 may be configured to control at least one of the generator 11, the applicator 10 and the at least one feeding device 2, possibly manually or automatically, independently of each other or in combination, based on physical and/or thermodynamic parameters detected by the sensor means.

Thus, the control unit 16 will change the operating conditions of the aforementioned components more quickly and accurately than prior devices.

The temperature of the sheet product as a result of the drying process performed by the operation unit 5 is determined according to the use environment condition of the apparatus 1.

This feature allows the operator to handle and stack the sheet products immediately after drying, thus greatly reducing the overall processing time.

Furthermore, this feature makes it possible to avoid the use of a cold air cooler downstream of the operating unit, which has high costs and maintenance requirements.

It has been found that pelts, pelts and artificial leathers treated with the above-described apparatus are less prone to reduce the useful leather area after treatment, even to increase the useful leather area, and their initial softness is not affected by the various treatment steps.

In the embodiment of the figures, the system 1 comprises a plurality of operating units 5A, 5B, 5C, one downstream of the other in the longitudinal feeding direction L.

It is clear that the number of units 5A, 5B, 5C may also be different from the number shown in the figures without departing from the scope of the invention.

The units 5A, 5B, 5C can be connected by the above-mentioned feeding device 2, in different cases the operator can manually transfer the sheet products from one operating unit to another at the end of the respective drying process.

Each unit 5A, 5B, 5C comprises at least one respective generator 11A, 11B, 11C, at least one respective applicator 10A, 10B, 10C and possibly at least one respective control unit 16A, 16B, 16C to generate an electromagnetic field of suitable strength in the respective chamber 6A, 6B, 6C.

In addition, each operating unit 5A, 5B, 5C may comprise a respective blowing device 18A, 18B, 18C and/or suction/drying device 19A, 19B, 19C and/or a sensor, which are adapted to operate as described above for each operating unit and which are connected to the control unit 16A, 16B, 16C.

The inventive device is susceptible of numerous changes and modifications within the inventive concept disclosed in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

Although the apparatus has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

INDUSTRIAL APPLICABILITY

The invention can find application industrially, since it can be produced on an industrial scale in tanneries, in particular in the surface treatment of hides, skins, artificial leathers and derivatives.