Energy regeneration oven for printing systems

Abstract

Energy regeneration oven for printing systems suitable for obtaining and storing electrical energy coming from the drying and crosslinking process of glue performed by common heating elements (11), which work at a temperature between 80 and 120°C; such energy regeneration being obtained by means of the installation of a panel (30) containing one or more Peltier cells (10); said panel (30) being suitable for installation in any existing DTE printing oven, at a cavity containing said heating elements (11); the energy obtained by means of the Seebeck effect by means of said Peltier cells (11) being subsequently stored within a special battery pack (21), in order to subsequently supply such energy to the same oven, thereby optimising energy consumption.

Description

[0001] DESCRIPTION

[0002] ENERGY REGENERATION OVEN FOR PRINTING SYSTEMS”

[0003] Field of the art

[0004] The invention relates to an innovative oven for printing on film with waterbased DTF technology, advantageously adapted to obtain electrical energy from one of its own processing processes, more in particular from drying by means of heating elements, obtaining an amount of electrical energy such as to partially support its subsequent processing.

[0005] Known art

[0006] The ovens used in the DTF (Direct to Film) printing process play a fundamental role in the drying and fixing steps of the prints. After the design has been printed on the film and the thermal adhesive powder has been applied, the ovens are used to heat the film itself, activating the adhesive necessary to prepare the transfer of the design onto the fabric. However, one of the main disadvantages in the use of such ovens is the high energy consumption, which can significantly affect overall operating costs. The operation of DTF ovens can occur through two main modes: convection and the use of infrared rays. In the first case, hot air is circulated around the film by means of fans, ensuring homogeneous heating. This process has a variable duration, generally ranging from two to ten minutes, depending on the specific temperature requirements and the type of thermal adhesive used. Instead infrared ovens do not heat the air, but the film itself, by means of radiation. This mode allows a faster drying process, but still involves significant energy consumption. The high energy requirements of DTF ovens mainly derive from the need to maintain high temperatures, between 100°C and I60°C, in order to correctly activate the adhesive powder. This requirement implies a considerable expenditure of energy, especially in operations of longer duration. Furthermore, most DTF ovens in use are not optimised for energy efficiency, resulting in heat dispersion that requires a greater amount of energy to maintain the desired temperatures. The fans used in convection ovens, or the high-power lamps used in infrared ovens, also contribute to the increase in electricity consumption, especially when the ovens remain in operation for prolonged periods. Today, therefore, DTF ovens are essential tools to ensure the quality and strength of prints. However, their energy consumption represents a challenge for companies that have to deal with increasing operating costs. Nowadays some companies are trying to adopt solutions aimed at improving operating efficiency. These include the use of ovens with improved thermal insulation, to reduce heat loss, and the rationalisation of production cycles, so as to prevent the ovens from being kept on unnecessarily. However, no company has obtained satisfactory results, and the sector is still hindered by the costs related to energy consumption.

[0007] Even patent US2024009977, published on 11 January 2024, does not solve the above problems, as it claims a laminated film usable in any application, for the purpose of reducing material consumption, compensating the energy costs related to the operation of the oven. The aim of our patent is instead to obtain electrical energy from the heat dispersion that distinguishes the drying step of the glue on the film, storing it within a battery pack to power and support the subsequent processing.

[0008] Description of the invention

[0009] According to the present invention, a flexible sanding pad for sanding bodywork is created which effectively solves the aforementioned problems.

[0010] The objective of the oven for printing with DTF technology described in the present patent application is to save electrical consumption, mainly derived from the heating elements, by converting part of the heat emitted, into electrical energy, using Peltier cells that, by means of the Seeback effect, are suitable for generating a flow of electrons when subjected to a temperature difference.

[0011] The energy regeneration oven for printing systems is therefore distinguished by its ability to recover and store electrical energy generated during the drying and crosslinking process of the glue, made by means of common heating elements operating at temperatures between 80°C and 120°C. This energy regeneration occurs by means of the installation of a panel provided with one or more Peltier cells. This panel can be installed on existing DTF printing ovens, at a cavity containing the heating elements. The energy produced through the Seebeck effect, by the Peltier cells, is subsequently stored in a special battery pack, allowing the reuse of this energy to power the oven itself, with the objective of optimising energy consumption.

[0012] The energy regeneration oven for printing systems is further provided with a photocell connected to a microcontroller, which detects the presence of the film to be processed.

[0013] The microcontroller, in turn, is suitable for activating the heating elements and the energy regeneration system, simultaneously starting a glue distribution and recharging system, a smoke extraction system, the movement of the belt on which the film runs, as well as the cooling fans of the processed film.

[0014] A further feature of the oven which is the subject of the invention is the presence of a perforated hopper, within which a brush is situated which is suitable for distributing the glue on the film by means of rotary movements, allowing the glue to slide through the holes. By way of non-limiting example, the movement of the brush contained within said perforated hopper is controlled by the microcontroller, which determines an automatic operating mode thereof, according to which a certain amount of glue is delivered per minute, based on the type of film treated; alternatively the movement of the brush contained within said perforated hopper is controlled manually, by means of an operator who is suitable for selecting the amount of glue that must flow on the film per minute, using a generic digital display arranged on the present oven.

[0015] Downstream of the hopper there is a protrusion of rubbery material, connected to a rotating axis, which comes into contact with the film, creating a vibration that eliminates excess glue. This process is particularly effective if the ink in the film is water-based, preventing the formation of lumps of powdered glue. By way of non-limiting example, a collection tank is suitable for being installed below said protrusion, in order to allow the collection and recirculation of the glue, directing the previously removed quantities to said perforated hopper for future processing.

[0016] The present oven is further provided with a motorized belt with extractor fan, which allows the film to adhere to the belt itself, ensuring a correct exposure of the glue to the heating elements for its crystallization. In parallel, an extractor fan with activated carbon filters is operated to remove the vapours produced by the thermal reaction during the drying of the ink and glue present on the film. In an embodiment thereof, said belt provides an automatic operating mode, suitable for moving the film at a pre-established speed and corresponding to a speed between 20 and 60 linear metres per hour; alternatively said belt provides a manual operating mode, by means of which the operator is suitable for setting the movement speed of the belt and therefore of the film by means of specific parameters present on the digital display. To instead accelerate the drying process, a series of fans are activated automatically, conveying cold air onto the film and thus lowering the temperature thereof following exposure to the heating elements. The oven further has an electrical winder, controlled by the microcontroller, which regulates the rotation of the axis on which the film collection cylinder is positioned, in sync with the advancement of the motorised belt. However, the essential element of the oven is the aforesaid panel, containing the plurality of Peltier cells, installed in the cavity of the heating elements where temperatures exceed 80°C. This panel is also designed to be compatible with existing DTF ovens, thanks to its subdivision into 40mm x 40mm modular spaces, each capable of accommodating a Peltier cell of varying thickness between 2 and 5 millimetres. The number of installable cells varies depending on the volume available in the oven cavity, consequently also affecting the electrical power obtained from the oven itself.

[0017] A heat dissipation system is positioned above said panel, which consists of aluminium alloy radiators that facilitate the recirculation of a cooling liquid inside the panel, ensuring a thermal differential of at least 60°C between the internal and external surfaces, fundamental for generating an electric flow through the Seebeck effect.

[0018] The recirculation system of the refrigerant liquid comprises a pump and a series of copper ducts, filled with refrigerant gas, which contribute to the dispersion of the accumulated heat.

[0019] Finally, the oven is provided with an inverter having a pure sinusoidal wave, connected to the panel with the Peltier cells, suitable for converting alternating current into direct current, enabling the storage thereof in the battery packs for subsequent use in future processing, thus improving the energy efficiency of the DTF printing system.

[0020] By way of non-limiting example, said inverter, in addition to being connected with the panel containing the Peltier cells, is suitable for being connected with a plurality of photovoltaic panels suitable for increasing the amount of electrical energy stored within the aforesaid battery pack. The advantages offered by the present invention are apparent in the light of the description set forth herein and will be further clarified by the accompanying figures and the detailed description.

[0021] Description of the figures

[0022] The invention will be described below in at least one preferred embodiment by way of non-limiting example and with the aid of the accompanying figures, in which:

[0023] • FIGURE 1 shows a simplifying diagram of the operation of the printing oven with DTF technology, which comprises the integration of a plurality of elements that allow the energy regeneration deriving from the exploitation of the heat emitted by the heating elements 11.

[0024] •FIGURE 2 instead shows a perspective external view of a common oven suitable for performing a printing with DTF technology; on said oven the panel 30 containing Peltier cells 10 has been inserted at the cavity where the aforesaid heating elements 11 are installed.

[0025] Detailed description of the invention

[0026] The present invention will now be illustrated by way of non-limiting or binding example, using the figures which illustrate some embodiments in relation to the present inventive concept.

[0027] With reference to FIG.1, the diagram is illustrated which is suitable for showing the operation of the printing oven with DTF technology which is the subject of the invention.

[0028] More in particular it is shown how the film 22, once it has entered the oven, is adapted to be monitored by means of photocells 13 which have the purpose of activating the subsequent processing components, such as the perforated hopper 12, which is suitable for depositing glue on such film 22. The excess glue, removed by means of a protrusion 15, is suitable for being deposited inside a collection tank, to be subsequently redirected towards the aforesaid hopper 12.

[0029] An advancement system 17 of the belt allows the speed of the film 22 to be adjusted and thus its exposure to the heating elements 11, which are suitable for emitting a heat that allows temperatures above 120°C to be reached. Such temperatures are exploited by a plurality of Peltier cells 10 for the generation of an electron flow, exploiting the Seebeck effect, when a thermal differential of at least 60°C is present. This thermal differential is obtained thanks to the presence of a panel 30, on which said cells 10 are installed on the internal surface, and a heat dissipation system 20 on the external surface. In fact, a refrigerant liquid flows within the dissipation system 20, which is suitable for being moved by means of a recirculation system 18, maintaining the temperature differential between the internal and external surface constant.

[0030] In fact, the refrigerant liquid is adapted to reach a tank 24 containing refrigerant liquid 25, thanks to the drive of a pump 23. The refrigerant liquid is suitable for transferring heat before returning to the interior of the panel 30, advantageously stabilising the thermal differential necessary to obtain the Seebeck effect. The electrical energy produced by said Peltier cells 10, in the form of alternating current, is converted into direct current by means of an inverter with pure sinusoidal wave, favouring the storage of such energy within a battery pack 21 to limit consumption on subsequent printing processes. With reference to FIG.2, an external view of a generic DTF oven is illustrated, on which said panel 30 containing Peltier cells 10 is suitable for being installed. Said panel 30, installed at the cavity containing the heating elements 11, allows to obtain electrical energy by exploiting the aforesaid thermal differential, thus storing the electrical energy following its conversion which occurred by means of an inverter 19.

[0031] The energy contained in the battery pack 21 will subsequently be used to power the subsequent processes, resulting in a net energy saving. Lastly, it is clear that the invention described up to now can be subjected to modifications, additions or variants obvious to those skilled in the art, without departing from the scope of protection outlined by the attached claims.

Claims

CLAIMS1. Energy regeneration oven for printing systems characterized in that it obtains and stores electrical energy coming from the drying glue process performed by common heating elements (11), which work at a temperature between 80 and 120°C; said energy regeneration being obtained by means of the installation of a panel (30) containing one or more Peltier cells (10); said panel (30) being suitable for installation in any existing DTF printing oven, in a cavity containing said heating elements (11); said energy obtained by means of the Seebeck effect by means of said Peltier cells (10) being subsequently stored within a special battery pack (21), in order to subsequently supply said energy to said oven, thereby optimising energy consumption; said energy regeneration oven for printing systems comprising:- at least one photocell (13), connected to a microcontroller, suitable for determining the presence of the film (22) which will subsequently be processed inside this oven using the DTF technology with water; this microcontroller being suitable for activating the heating elements (11), at the same time as the energy regeneration system consisting of the above- mentioned panel (30); said microcontroller being further suitable for activating a glue distribution and recharging system, a smoke extraction system, an advancement system (17) for a belt on which the film (22) runs, and finally the cooling fans for the obtained film (22);- at least one perforated hopper (12), comprising within it a brush for distributing the glue on the film (22) by means of rotary mechanical movements, sliding it through said holes;- at least one protrusion (15), installed downstream of said hopper (12); said protrusion (15) being made of a rubbery material and being connected to an axle which, by rotating, generates a contact with the film (22); said mechanical contact creates a vibration with the film (22) which allows theelimination of the excess glue; should the ink printed on the film (22) be water-based, the shaking would allow the glue powder not to create lumps;- at least one motorized belt, integrated with an extractor fan, suitable to make the film (22) adhere to said belt in order to follow its advancement; said guided advancement being apt to allow the maximum exposure of the glue included to the heating elements (11), which allow its crystallisation;- at least one extractor fan equipped with activated carbon filters, suitable to be operated at the same time as said heating elements (11), in order to remove all the vapours generated by the thermal reaction inherent in the drying of the ink and the glue present on the film (22);- a plurality of fans suitable for conveying cold air onto the film (22), speeding up its drying and, above all, decreasing its temperature following exposure to said radiating elements (11); said fans being capable of operating in a fully automatic manner, simultaneously with the operation of the radiating elements (11);- at least one electrical winder (16), controlled by the microcontroller, capable of establishing the rotation of the axis on which the film (22) is placed, based on the advancement generated by the movement of said belt;- at least one panel (30), comprising at least one Peltier cell (10), suitable for installation in the cavity where said heating elements (11) are installed, where temperatures exceed 80°C; said panel (30) being suitable for installation inside already existing DTF ovens, being adapted to the size of the relative cavity; said adaptation being allowed by the subdivision of the panel (30) into a plurality of spaces of size 40mm x 40mm each suitable to contain a Peltier cell (10) which has a thickness varying from 2 to 5 millimetres; each panel can therefore be equipped with a variable number of cells (10), depending on the volume available inside the DTF oven cavity;- at least one heat dissipation system (20), located at the top of said panel (30), therefore on the opposite side to the surface of the panel (30) exposed to the radiating elements (11); said heat dissipation system (20) being composed of a plurality of aluminium alloy radiators suitable to allow the recirculation of a cooling liquid inside the panel (30), ensuring a thermal differential of at least 60° between the internal surface and the external surface; said thermal differential being necessary to generate an electric flow according to the Seebeck effect;- at least one recirculation system (18) of the refrigerant liquid, capable of reaching a basin (24), containing the cooling liquid (25), after having absorbed heat from the radiating elements (11); said recirculation system (18) comprising a pump (23) and a plurality of ducts of different sections made of copper, which by means of a refrigerant gas allow an effective dispersion of heat from said refrigerant liquid;- at least one inverter (19) having a pure sinusoidal wave, connected to said panel (30) containing the plurality of Peltier cells (10), capable of converting alternating current into direct current, enabling its storage in suitable battery packs (21) for subsequent use in future processes.

2. Energy regeneration oven for printing systems, according to claim 1 above, characterized in that the movement of the brush contained within said perforated hopper (12) is controlled by the microcontroller, which determines an automatic operation mode, according to which a certain amount of glue per minute is dispensed, depending on the kind of film (22) treated.

3. Energy regeneration oven for printing systems, according to claim 1 above, characterized in that the movement of the brush contained within said perforated hopper (12) is manually controlled, by means of an operator which is apt to select the quantity of glue which is to flow onto the film per minute, using a generic digital display arranged on said oven.

4. Energy regeneration oven for printing systems, according to any one of the preceding claims, characterized in that a collection tank (14) is apt to be installed inferiorly to said protrusion (15), in order to allow the collection and recirculation of the glue, directing the previously removed quantities to said perforated hopper (12) for future processing.

5. Energy regeneration oven for printing systems, according to any one of the preceding claims, characterized in that said belt provides an automatic operating mode, able to move the film (22) at a pre-established speed ranging between 20 and 60 linear metres per hour.

6. Energy regeneration oven for printing systems, according to any one of the preceding claims 1 to 4, characterized in that said belt provides a manual operating mode, by means of which the operator is able to set the speed of movement of the belt and therefore of the film (22) by means of specific parameters available on a digital display.

7. Energy regeneration oven for printing systems, according to any one of the preceding claims, characterized in that said inverter (19), in addition to being connected with the panel (30) containing Peltier cells (10), is apt to be connected with a plurality of photovoltaic panels apt to increase the amount of electrical energy stored within said battery pack (21).

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