ROTARY CHEMICAL REACTOR FOR TANNING WITH PROCESS OPTIMIZED THROUGH THE USE OF ULTRASOUND

Description

“ROTATING CHEMICAL REACTOR FOR TANNING WITH PROCESS OPTIMIZED THROUGH THE USE OF ULTRASOUND” TECHNICAL SECTOR OF THE INVENTION

[001] The present invention relates to a rotating chemical reactor for processing leather or the like.

[002] Furthermore, the invention relates to a method which provides for the use of said rotating chemical reactor. STATE OF THE ART

[003] The processing of leather, from raw hide to finished leather, allows the transformation of animal skins making them resistant, elastic, waterproof and rot-proof by bathing them in various types of chemical products.

[004] The well-known rotating chemical reactors (called drums according to a terminology widespread in the relevant technical sector) for the processing of leather, fabrics, or similar materials, are containers, mostly of a substantially cylindrical shape, mounted on suitable support structures that allow them to rotate around their axis. The axes are generally perforated to allow both the supply of water and products, the control of the internal pressure, and the assembly of accessories and fixed or rotating manifolds. The manifolds can be used to bring steam, electrical energy, compressed air, inside the reactor. Special rotating seals mounted on the axes allow the rotation of the reactor while allowing the manifolds to remain stationary.

[005] Internally, the reactor is equipped with blades, spigots and other internal elements with the most diverse dimensional characteristics, mainly intended to exert a mechanical action on the processed products. In fact, inside the chemical reactor there are the skins, Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 left free, and the chemical treatment bath. The rotation of the chemical reactor causes a variable interaction between the hides, the chemical bath, and the internal surfaces of the chemical reactor consisting of the internal cylindrical surface and the surfaces of the aforementioned internal elements.

[006] Many factors influence this interaction which is aimed at obtaining three distinct effects on the hides: a chemical effect, a mechanical effect and a peristaltic effect. The chemical effect, due to the interaction between the hides and the chemical bath, is optimised by precisely controlling the composition and temperature of the chemical bath inside the drum during all the stages of the hide treatment. To do this, means are used for adding chemical products to the rotating chemical reactor, filtration, heating, recirculation, control of the concentrations of the various chemical substances and others. The water and the chemicals that form the chemical bath are usually introduced into the rotating chemical reactor through the hollow shafts of the drum itself.

[007] As an alternative to the drum process, there are also known solutions that propose subjecting the hides to be treated to an ultrasonic current produced by sonotrodes positioned on the bottom of a tank containing a chemical bath to promote the penetration of the chemical solution into the hides to be treated, as disclosed, for example, in the previous document IT102022000010121. This effect is given by the fact that the animal skin behaves as a sound-absorbing material, concentrating on itself the mechanical action of the ultrasounds delivered by the sonotrodes. Furthermore, the application of ultrasonic energy promotes the emulsification and some other reaction kinetic mechanisms.

[008] There is therefore a need to provide an improved tanning process as well as an improved tanning apparatus. SUMMARY OF THE INVENTION

[009] An object of the present invention is to address the drawbacks complained of with reference to the state of the art.

[0010] These and other purposes are achieved with a rotating chemical reactor apparatus, Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 according to claim 1.

[0011] Some advantageous embodiments are the subject of the dependent claims.

[0012] According to one aspect of the invention, a rotating chemical reactor for processing hides or similar, comprises a rotating container that defines an internal volume, said rotating container being provided with: means for supplying a chemical bath, and at least one door for loading and unloading said hides, and a motor for rotating the rotating container around an axis of rotation.

[0013] The rotating container comprises a plurality of sonotrodes operatively facing its internal volume.

[0014] According to one embodiment, the sonotrodes of said plurality are distributed along the axis of rotation of the rotating container.

[0015] In one embodiment, a shaft is arranged in the internal volume at the rotation axis of the rotating container, and said plurality of sonotrodes are attached to said shaft. The sonotrodes may be arranged internally to said shaft in a protected and fluid-tight position with respect to the chemical bath. For example, the sonotrodes may be arranged on the central axis of the rotating container, and the chemical bath inside the drum is introduced to reach above the level of the rotation axis, so that the shaft mounting the sonotrodes remains submerged when in operating conditions.

[0016] The shaft is preferably made of metal, such as stainless steel, to aid in the transmission of ultrasound, as well as to aid in fluid sealing.

[0017] According to one embodiment, the rotating container is mounted on a support structure so that it can rotate relative to it and which may comprise two rotating supports. The two rotating supports are preferably hollow to allow axial mounting of the shaft and seals are provided between the shaft, which remains fixed and constrained to the support structure, and the supports which rotate integrally with the rotating container.

[0018] According to one embodiment, the rotating container is mounted so as to be able to rotate relative thereto and the shaft containing sonotrodes of said plurality is constrained to the Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 rotating container and therefore rotating with it.

[0019] The activation and / or deactivation of at least some sonotrodes of the said plurality of sonotrodes may be electronically controlled.

[0020] According to one embodiment, the rotating container comprises perimeter walls that delimit the internal volume, wherein the sonotrodes of said plurality are fixed to at least one of the perimeter walls. In particular, the perimeter walls comprise two opposite bottom walls and the sonotrodes of said plurality are arranged on at least one bottom wall.

[0021] An electronic control system may be provided in operational connection with the sonotrodes of said plurality to control the activation and / or deactivation of said sonotrodes so that they are active, during rotation of the rotating container, i.e., when in operating conditions, only when submerged in the chemical bath. In particular, the electronic control system may be configured to control the activation and / or deactivation of the sonotrodes of said plurality based on information on the angular position of the rotating container.

[0022] According to an aspect of the invention, a method for processing hides or the like comprises the steps of: (i) providing a rotating chemical reactor for processing hides or the like, comprising a rotating container defining an internal volume, which is provided with means for supplying a chemical bath, with at least one door for loading and unloading said hides, and with a motor for rotating the rotating container itself around a rotation axis; and (ii) inserting a chemical bath into the internal volume of the rotating container; and (iii) arranging the hides in the internal volume; and (iv) setting the rotating container into rotation; and (v) supplying ultrasonic energy by means of said plurality of sonotrodes which are contained within the central shaft, which is immersed in the chemical bath, keeping the sonotrodes mounted inside the shaft itself isolated from the chemical bath.

[0023] By providing ultrasonic generators inside a tannery drum, it is possible to carry out the tanning and / or retanning process in the drum with the aid of ultrasound.

[0024] Thanks to the proposed solutions, a uniform ultrasonic excitation is allowed and Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 controlled inside the rotating vessel of the tannery reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The characteristics of the invention will be easily understood from the following description of embodiments thereof, provided as non-limiting examples, with reference to the attached figures in which: - Figure 1 is a vertical sectional view of an apparatus, according to one embodiment; - figure 2 illustrates the box indicated by arrow II in figure 1. - Figure 3 is a vertical sectional view of an apparatus, according to one embodiment; - figure 4 illustrates the box indicated by the arrow IV in figure 3. DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0026] In accordance with a general embodiment, a rotary chemical reactor apparatus 10 for processing hides or skins or drum 10 is provided in accordance with terminology common in the relevant art.

[0027] The apparatus 10 comprises a rotating container 11 which defines an internal volume 12. Said rotating container is a closed container provided with means 13 for supplying a chemical bath and with at least one door for loading and unloading the hides and liquids. The chemical bath is arranged in the internal volume 12, and for example approximately two-thirds of the internal volume 12 of the rotating container 11 is filled with chemical bath solution. In addition to the means of supply 13, such as a duct, a vent system 17 may be provided (such as one or more ducts and / or one or more vent valves) which connects the upper portion of the rotating container above the level of the chemical bath with the outside, avoiding overpressure. Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836

[0028] The apparatus 10 comprises a motor 14 for rotating the rotating container 11 around a rotation axis X.

[0029] In accordance with one embodiment, the rotating container 11 with the internal volume 12 has a substantially cylindrical development around the rotation axis X, which is preferably oriented in a horizontal or sub-horizontal direction.

[0030] A support structure 18 may be provided for the rotating container 11 so that the latter can rotate about its rotation axis X. The support structure 18 preferably comprises one or more ground supports and an anti-rotation system connected to the base which prevents the rotation of the shaft 16 when the rotating container 11 rotates. The motor 14 may be installed on the support structure 18 and means for transmitting the motion may be provided between the motor 14 and the rotating container 11.

[0031] As shown for example in figure 1, the rotating container 11 preferably rotates with respect to the shaft 16, which is therefore stationary (i.e. does not rotate) with respect to the support structure 18. The shaft 16 may be made internally hollow and may receive the supply means 13 and / or the venting system 17 of the chemical bath. Rolling elements are preferably mounted between the shaft 16 and the rotating container 11 and a sleeve coaxial with the shaft 16 may be provided to ensure fluid tightness. Alternatively, the shaft 16 may be made integral in rotation with the rotating container 11.

[0032] When in operating conditions, where the rotating container 11 is driven into rotation, the chemical bath tends to remain at the bottom i.e. in the lower portion of the rotating container. The internal volume 12 of the rotating container 11 can be filled up to approximately two-thirds by submerging the shaft 16 in the chemical bath for any angular position of the rotating container relative to its support structure.

[0033] Advantageously, the rotating container 11 comprises a plurality of sonotrodes 15 facing the internal volume 12. Thanks to the provision of said plurality of sonotrodes 15, it is possible to generate ultrasonic vibrations in the internal volume 12, which have an encouraging effect on the penetration of the chemical bath into the skin and are able to provide other electro-chemical-physical benefits to the chemical bath itself. The sonotrodes 15 immersed in the bath Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 chemical can be configured to emit ultrasound at a frequency between 20 and 2000 kHz, and in particular excitations at lower frequencies, substantially below 150 kHz, generate shock waves and micro-convective currents while at higher frequencies chemical processes such as the production of hydroxyl radicals are favored, as well as the increase in the kinetics of chemical reactions and the promotion of emulsion mechanisms.

[0034] It is therefore desirable that the ultrasound propagation occurs through a liquid phase of the chemical bath. In accordance with a preferred embodiment, the sonotrodes 15 of said plurality are distributed along the rotation axis X of the rotating container 11 (which is preferably also the median axis around which the cylindrical body of the rotating container develops). In this way, when in the operating condition in which the chemical bath submerges the rotation axis X of the rotating container, the sonotrodes are always immersed, regardless of the angular position of the rotating container. Furthermore, the provision of a cylindrical internal volume favors uniform excitation by means of the sonotrodes 15 distributed along the rotation axis X.

[0035] In particular, in accordance with a preferred embodiment, the sonotrodes 15 of said plurality are mounted internally to the rotation shaft 16, i.e. the shaft 16 is hollow and has the sonotrodes inside it, i.e., in other words, the shaft 16 has a longitudinal cavity in which the sonotrodes 15 are placed.

[0036] The shaft 16, as mentioned above, is preferably fixed to the support structure 18 i.e. does not rotate together with the rotating container. Of course, according to another embodiment, the rotation shaft may rotate in conjunction with the rotating container and the sonotrodes 15 of said plurality are however always submerged in the chemical bath. In this case, a rotating electrical collector or other means of supplying energy to the sonotrodes may be employed.

[0037] For example, said rotating container 11 is mounted to the support structure 18 so as to be able to rotate relative to it and in particular the shaft 16 is mounted to the support structure 18 and rotating fluid sealing elements are provided between the shaft 16 and the rotating container 11 and / or between the support structure 18 and the rotating container 11.

[0038] For example, said rotating container 11 is integral in rotation with said shaft 16, Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 and wherein the shaft is connected to the support structure 18 so as to be able to rotate relative thereto, and rotating sealing elements are provided between the shaft 16 and the support structure 18 and / or between the rotating container 11 and the support structure 18.

[0039] The sonotrodes 15 are preferably distributed, in the internal volume 12, over the entire extension of the shaft 16, i.e. of the rotation axis X, to achieve a uniform delivery of ultrasound. For example, in the hollow body of the shaft 16 the sonotrodes of said plurality are mounted, connected, wired, powered and controlled.

[0040] Preferably, the shaft 16 comprises a fluid-tight portion that is fluidically isolated from the internal volume 12, preventing it from being wetted by the chemical bath, and the sonotrodes of said plurality 15 are housed in said fluid-tight portion, resulting in fluidically isolated from the chemical bath. Said fluid-tight portion may be made with a sleeve arranged coaxially with the shaft 16 and / or by sealing the internal cavity of the shaft 16.

[0041] The distance between adjacent sonotrodes, as well as the direction of exposure to the internal volume of the rotating container, can be chosen based on the desired ultrasonic excitation effect. According to one embodiment, the sonotrodes 15 are equally spaced from each other and all face the same side of the rotation axis X, as shown for example in figure 2. The shaft 16 preferably has a metal body (for example stainless steel) suitable for the propagation of ultrasound. The sonotrodes can be mounted on multiple longitudinal lines with mounting angles between them and distances that can be adjusted to obtain the desired ultrasonic excitation effect, such as for example they can extend along a double helix wrapped around the rotation axis X.

[0042] The activation and deactivation of the sonotrodes 15 is preferably controlled electronically by an electronic control system. For example, at a given moment, some sonotrodes may be activated and others deactivated by means of the electronic control system based on the detection of environmental parameters of the internal volume and / or on the basis of the angular coordinate of the rotating container 11. The control system may have available for programming the activation of the sonotrodes 15 the parameters relating to the Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 Tanning and / or retanning process. These parameters may include weights, temperatures, pH controls, and product dosage reports.

[0043] Alternatively or in addition, at least some sonotrodes 15 may be located in the cylindrical side walls 21 and / or in the bases 20, in other words in the perimeter walls of the rotating container 11. In this case, the sonotrodes may be located on one or more areas of the bottom walls 20 arranged in proximity to the rotation axis X, thus always being submerged in the liquid bath when in operating conditions due to the fact that the chemical bath occupies more than half of the internal volume 12. Preferably, the cylindrical side walls 21 and / or the bases 20 which mount the sonotrodes 15 may comprise their respective fluid-tight portions which are fluidically isolated from the internal volume 12 i.e. from the chemical bath.

[0044] The shaft 16 extending inside the internal volume 12 along the rotation axis X is not necessarily present and for example there could only be supports arranged externally to the rotating container 11 and suitable for allowing the rotation of the latter with respect to the rotation axis X. In this case, the sonotrodes 15 can be arranged on the perimeter walls of the rotating container 11 facing the internal volume 12. In particular, as shown for example in figure 3, the sonotrodes 15 of said plurality are preferably mounted on the bottom walls 20 of the rotating container 11.

[0045] In accordance with another embodiment, the sonotrodes 15 are mounted on one or more perimeter walls and are intermittently immersed in the liquid bath, i.e., they are immersed as a function of the angular coordinate of the rotating container 11. In this case, the sonotrodes 15 may be distributed uniformly, along a circular path around the rotation axis X, to ensure uniform delivery during rotation of the container. Alternatively or in addition, the sonotrodes may be arranged on one or more bottom walls 20 in rows or radii that diverge from the rotation axis X to ensure uniformity of ultrasonic excitation in the internal volume 12.

[0046] In accordance with a preferred embodiment, at least some sonotrodes 15 are mounted on one or more perimeter walls of the container, and the rotating chemical reactor apparatus Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 includes an electronic control system in operative connection with the sonotrodes 15 of said plurality for controlling the activation and / or deactivation of the sonotrodes, so that they are active only when submerged in the chemical bath. In accordance with one embodiment, said electronic control system is configured to control the activation and / or deactivation of the sonotrodes based on information on the angular position of the rotating container 11. Information on the angular position of the rotating container 11 may be acquired by said motor 14 or by one or more sensors 22 that may be mounted on the support structure 18 (fixed, i.e., not rotating when in operating conditions). As shown for example in Figure 4, a position sensor 22 may be provided on the support structure 18 to acquire information on the angular coordinate of the rotating container 11.

[0047] The perimeter walls of the rotating container 11, preferably comprising two opposing bottom walls 20 and a cylindrical side wall 21, may be made of metal, such as stainless steel, so that they propagate the ultrasonic vibrations. On the internal side of the perimeter walls facing the internal volume 12, mechanical stress means 19 may be provided to induce mechanical effects on the skins, such as blades and spigots.

[0048] A method for working with leather or similar will be described below.

[0049] The method involves a rotating chemical reactor 10 according to any of the previously described embodiments, introducing a chemical bath into the internal volume 12 of the rotating container 11 (for example by using the supply means 13), loading the hides into the internal volume 12.

[0050] Furthermore, the method comprises the phases of rotating the rotating container 11 and supplying the ultrasonic energy by means of the sonotrodes 15 of said plurality. The activation and intensity parameters of the sonotrodes can be suitably adjusted according to the different types of leathers and processes.

[0051] As mentioned above, the ultrasound delivery can be managed by a programming system (electronic control system) which provides for the availability of data and which Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 allows you to make a program related to the single desired process.

[0052] As mentioned above, to optimize the performance of the ultrasound and its duration, it is important to operate the sonotrodes of said plurality only when they are submerged in the chemical bath, in case they could remain uncovered during rotation. For this purpose, the electronic control system can be programmed for the optimal activation of the sonotrodes.

[0053] The use of ultrasound, thanks to the proposed solutions, allows both to improve the skin's ability to absorb products and the skin's reactivity to the products, as well as to improve the characteristics of the products.

[0054] These and other advantages of the invention remain even in the presence of variants and embodiments of the invention other than those described above and shown in the attached figures that may be envisaged by a technician in the sector, remaining within the scope of protection defined by the claims that follow.

Claims

1. Rotating chemical reactor apparatus (10) for processing hides or similar, comprising - a rotating container (11) defining an internal volume (12), said rotating container (11) being provided with means for supplying (13) a chemical bath, and with at least one door for loading and unloading said hides; - a motor (14) for rotating the rotating container (11) around a rotation axis (X); characterised in that said rotating container (11) comprises a plurality of sonotrodes (15) operatively facing the internal volume (12).

2. A rotating chemical reactor apparatus according to claim 1, wherein the sonotrodes (15) of said plurality are distributed along the rotation axis (X) of the rotating container (11), preferably over the entire extension, in the internal volume (12), of the rotation axis.

3. Rotating chemical reactor apparatus according to claim 1 or 2, wherein a shaft (16) is arranged in the internal volume (12) in correspondence with the rotation axis (X) of the rotating container (11); and wherein the sonotrodes (15) of said plurality are fixed to said shaft (16); wherein, preferably, the rotating container (11) has a substantially cylindrical development around the rotation axis (X) or around said shaft (16).

4. A rotary chemical reactor apparatus according to claim 3, wherein said shaft comprises hollow body and the sonotrodes (15) of said plurality are arranged inside the hollow body of the shaft (16).

5. Rotating chemical reactor apparatus according to claim 3 or 4, wherein said shaft (16) comprises a fluid-tight portion thereof which is fluidically isolated from the chemical bath of the internal volume, and wherein the sonotrodes (15) of said plurality are arranged in said fluid-tight portion, resulting in fluidically isolated from the chemical bath of the internal volume of the rotating container. Eng. Antonio Leotta Register Prot. n.1253 BM ITALBREVETTI B1836 6. A rotary chemical reactor apparatus according to any of claims 3 to 5, wherein said rotary vessel (11) is mounted to a support structure (18) so as to be able to rotate relative thereto; and wherein, the shaft (16) is connected to the support structure (18); and wherein, preferably, rotary sealing elements are provided between the shaft (16) and the rotary vessel (11) and / or between the support structure (18) and the rotary vessel (11).

7. A rotary chemical reactor apparatus according to any of claims 3 to 5, wherein said rotating container (11) is rotatably integral with said shaft (16), and wherein the shaft is connected to a support structure (18) so as to be able to rotate relative thereto; and wherein, preferably, rotating sealing elements are provided between the shaft (16) and the container and between the support structure (18) and / or between the rotating container (11) and the support structure (18).

8. A rotary chemical reactor apparatus according to any of the preceding claims, wherein said shaft (16) comprises said chemical bath supply means (13) and / or a wired connection of the sonotrodes (15) of said plurality.

9. A rotating chemical reactor apparatus according to any preceding claim, wherein the rotating container (11) comprises perimeter walls delimiting the internal volume (12); and wherein the sonotrodes (15) of said plurality are fixed to the perimeter walls; and wherein, preferably, the perimeter walls comprise two opposite bottom walls (20) and the sonotrodes of said plurality are arranged on at least one bottom wall (20).

10. The rotating chemical reactor apparatus of claim 9, further comprising an electronic control system in operative connection with the sonotrodes (15) of said plurality for controlling the activation and / or deactivation of said sonotrodes to ensure that they are active during rotation only when submerged in the chemical bath.

11. A rotating chemical reactor apparatus according to claim 10, wherein the electronic control system is configured to control the activation and / or deactivation of the sonotrodes (15) of said plurality based on information on the angular position of the rotating container (11); wherein, preferably, said angular position of the rotating container is determined by acquiring information from one or more sensors (22). Ing. Antonio Leotta Albo Prot. n.1253 BM ITALBREVETTI B1836 12. A rotary chemical reactor apparatus according to any preceding claim, wherein the rotating vessel (11) is made of metal, e.g. stainless steel, and / or wherein said shaft (16) is made of metal, e.g. stainless steel.

13. A method for processing hides or similar materials comprising the steps of: - providing a rotating chemical reactor apparatus (10) according to any of the preceding claims; - inserting a chemical bath into the internal volume (12) of the rotating container (11); - arranging said hides into the internal volume (12); - setting the rotating container (11) into rotation; - supplying ultrasonic energy by means of the sonotrodes (15) of said plurality which are immersed in the chemical bath.