Printing machine with heat recovery device

Abstract

The utility model discloses a printing machine with a heat recovery device, which relates to the technical field of environmental protection and energy conservation and comprises a drying box, rollers in the drying box are provided with heating units used for heating and drying printed materials flowing through the drying box; a heat exchange assembly of the printing machine comprises a first heat exchanger and a second heat exchanger. The first heat exchanger comprises a gas flowing cavity and a liquid flowing cavity which are isolated from each other; the air inlet end of the air flowing cavity communicates with the air outlet, and the air outlet end communicates with the external environment. The second heat exchanger is arranged in the drying box; a pipeline is arranged between the second heat exchanger and the liquid flowing cavity to form a closed circulating water path; a circulating water pump is arranged on the pipeline; liquid flowing through the liquid flowing cavity exchanges heat with gas flowing through the gas flowing cavity through the first heat exchanger; gas input from the air inlet of the drying box exchanges heat with liquid flowing through the second heat exchanger through the second heat exchanger. And finally, the heat utilization rate is improved, and heat emission is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental protection and energy conservation, and particularly relates to a printing machine with a heat recovery device. Background Art

[0002] The kitchen paper printing machine is specially designed to customize patterns and texts for kitchen paper, and is widely used in the fields of catering, household and personal care, endowing products with unique charm and personalized identification. However, in the printing process, ink and dye particles may volatilize into the air, mixed with fine fibers, affecting the workshop environment. Although the drying step ensures the drying of the paper towels, it also promotes the evaporation of solvents and moisture, carrying more fine fibers and drifting. In addition, it cannot be ignored that the release of VOC waste gases in ink and dyes, such as harmful solvents like toluene and ethyl acetate, not only endangers the health of workers, but also poses a potential threat to the environment. Therefore, while pursuing beauty and personalization, effective measures need to be taken to deal with these by-products to ensure the environmental protection and safety of the production process.

[0003] Currently, in printing production, basically the gases discharged from drying are treated by "spraying", "cooling + electrostatic" treatment, or carbon adsorption treatment to reduce the emission of VOC waste gases. For example, an inkjet printing machine and its processing technology provided in the patent document with the publication number CN115891450B adopt the "spraying + drying" treatment. However, as the gases treated by drying as described above themselves have a certain amount of heat, directly discharging them into the air not only causes waste of thermal energy, but may also have a secondary impact on the environment, such as forming a local heat island effect or affecting air circulation. In addition, the fibers carried in the gases are directly discharged, which affects the environmental quality and also causes equipment blockage.

[0004] Therefore, there is an urgent need to provide a printing machine with a heat recovery device to solve the above technical problems. Summary of the Invention

[0005] In view of the problems in the related art, the utility model proposes a printing machine with a heat recovery device, which can effectively improve the utilization rate of heat.

[0006] The utility model is realized as follows:

[0007] A printing machine with a heat recovery device includes a drying box. A plurality of rollers are arranged in the drying box, and the rollers are provided with heating units for drying the printing substrates flowing through the rollers; the drying box is provided with an air inlet and an air outlet.

[0008] The printing machine further includes a heat exchange component; the heat exchange component includes a first heat exchanger and a second heat exchanger; the first heat exchanger includes a gas flow chamber and a liquid flow chamber that are isolated from each other; the gas flow chamber includes an air inlet end and an air outlet end, the air inlet end is communicated with the air outlet, and the air outlet end is communicated to the external environment; the second heat exchanger is arranged inside the drying box; a pipeline is connected between the second heat exchanger and the liquid flow chamber to form a closed circulating water path; a circulating water pump is arranged on the pipeline;

[0009] The liquid flowing through the liquid flow chamber and the gas flowing through the gas flow chamber exchange heat through the first heat exchanger; the gas input into the drying box from the air inlet exchanges heat with the liquid flowing through the second heat exchanger through the second heat exchanger.

[0010] The substrate, i.e., the paper towel or fabric to be printed, etc., is controlled to move in the printing machine by rollers.

[0011] The working principle is as follows: The drying box extracts air, i.e., gas, from the external environment through the air inlet. The gas passes through the rollers and the substrate on the rollers, takes away the moisture on the substrate, dries the substrate, and at the same time absorbs the heat generated by the rollers, i.e., forms hot and humid air, which is about 80°C. The hot and humid air enters the gas flow chamber from the air outlet, and the heat is absorbed by the liquid in the liquid flow chamber and then discharged to the external environment; at this time, the temperature of the liquid rises from about 40°C to 65°C, and the temperature of the discharged gas drops from 80°C to about 45°C.

[0012] After the liquid passing through the liquid flow chamber absorbs heat, it is pumped to the second heat exchanger by the circulating water pump. At this time, the gas entering the drying box from the air inlet absorbs the heat of the liquid through the second heat exchanger and forms hot air blowing towards the substrate; the hot air formed at this time is about 55°C. The heat of the absorbed liquid is pumped back to the first heat exchanger again.

[0013] Finally, the reuse of the discharged heat is realized, the utilization rate of the heat generated in the drying box is improved, and the heat finally discharged into the environment is reduced.

[0014] As a further optimization of the above solution, the first heat exchanger includes a housing with openings at both ends and one or more heat exchange tubes arranged in the middle; a number of evenly arranged fins are attached to the outer surface of the heat exchange tubes;

[0015] The inner cavity of the heat exchange tube forms the liquid flow chamber; the gaps between the openings at both ends of the housing and the fins form the gas flow chamber.

[0016] The second heat exchanger can also be realized by adopting the structure of the first heat exchanger.

[0017] As a further optimization of the above solution, the fin is an L-shaped bent structure, and an arc angle is formed at the bending position; one side of the fin is fixedly attached to the heat exchange tube, and the other side is attached to the adjacent fin to form a back-to-back connection.

[0018] Due to production process limitations, the side of the existing fin that fits the heat exchange tube can have a maximum of 5 mm, otherwise the structural strength will be affected; if directly arranged in an array, the gap between the fins will be too small, that is, at most 5 mm, and the fibers carried in the exhaust gas are likely to block in the gap; setting the fins back-to-back can increase the gap to about 10 mm without changing the fin structure, reducing the risk of fiber blockage.

[0019] As a further optimization of the above solution, both the first heat exchanger and the second heat exchanger are made of metal.

[0020] As a further optimization of the above solution, there are multiple second heat exchangers, which are evenly spaced; a first air cavity is formed along the outer peripheral side of the multiple second heat exchangers; a second air cavity is formed along the outer peripheral side of the multiple rollers; the first air cavity and the second air cavity are isolated from each other, and only one communication port is provided;

[0021] The air inlet is provided on the first air cavity, and the air outlet is provided on the second air cavity.

[0022] Two independent air cavities are provided, so that the air can fully exchange heat with the second heat exchanger in the first air cavity, and then fully contact and dry the printed matter in the second air cavity.

[0023] As a further optimization of the above solution, the air inlet and the communication port are respectively provided at both ends of the first air cavity; the air outlet and the communication port are respectively provided at both ends of the second air cavity.

[0024] The positions of the air inlet and the air outlet relative to the communication port can make the air contact and exchange heat with the second heat exchanger and the printed matter more fully. Further, the air inlet, the communication port and the air intake are arranged from bottom to top in the drying box, further improving the heat utilization effect.

[0025] As a further optimization of the above solution, an expansion tank is also connected to the pipeline for stabilizing the water pressure of the circulating water path.

[0026] The working principle of the expansion tank is to use a part of the space inside the tank to accommodate the water whose volume changes due to temperature changes. When the water in the system expands due to heat, the excess water enters the expansion tank, thus avoiding too high system pressure; when the water in the system cools and contracts, the water in the expansion tank can flow back into the system to maintain the stability of the system pressure.

[0027] As a further optimization of the above solution, the air outlet end of the first heat exchanger is connected to the chimney.

[0028] As a further optimization of the above solution, an activated carbon adsorption device is provided between the chimney and the air outlet end.

[0029] The activated carbon adsorption device is used to remove harmful substances in the waste gas, including volatile organic compounds (VOCs) and other harmful gases, so as to realize the purification and up-to-standard discharge of the waste gas.

[0030] As a further optimization of the above solution, an induced draft fan is also provided between the activated carbon adsorption device and the chimney.

[0031] The main function of the induced draft fan is to generate negative pressure to help extract and transport the gas after being treated by the activated carbon, ensure the continuity and stability of the gas flow, and at the same time discharge the treated gas into the chimney to realize the high-altitude discharge of the waste gas.

[0032] The beneficial effects are as follows:

[0033] The utility model provides a printing machine with a heat recovery device. By setting a first heat exchanger, a second heat exchanger and pipelines, and using a circulating liquid as a heat exchange medium, the heat exchange with the air at both the air inlet and outlet ends of the drying box is realized, and finally the efficient utilization of the heat generated in the drying box is achieved, reducing the heat emission to the external environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic connection diagram of a part of the structure of the printing machine provided in Embodiment 1 of the utility model;

[0035] Figure 2 It is a schematic structural diagram of the first heat exchanger provided in Embodiment 1 of the utility model;

[0036] Figure 3 It is a schematic structural diagram of the cooperation between the heat exchange tube and the fin provided in Embodiment 1 of the utility model;

[0037] Figure 4 It is a schematic connection diagram of a part of the structure of the printing machine provided in Embodiment 2 of the utility model.

[0038] Reference Signs:

[0039] 1. Drying box; 11. Air inlet; 12. Air outlet; 13. First air cavity; 14. Second air cavity; 15. Communication port;

[0040] 2. Roller;

[0041] 3. First heat exchanger; 31. Shell; 32. Heat exchange tube; 33. Fin; 34. Gap; 35. Air inlet end; 36. Air outlet end;

[0042] 4. Second heat exchanger;

[0043] 5. Activated carbon adsorption device;

[0044] 6. Induced draft fan;

[0045] 7. Chimney;

[0046] 8. Pipeline; 81. Circulating water pump; 82. Expansion tank;

[0047] 9. Substrate. Specific embodiments

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1

[0050] As Figures 1 to 3 shown, this embodiment provides a printing machine with a heat recovery device, including a drying box 1. A plurality of rollers 2 are provided in the drying box 1, and a heating unit is provided on the rollers 2 for drying the substrate 9 flowing through the rollers 2; the drying box 1 is provided with an air inlet 11 and an air outlet 12;

[0051] The printing machine further includes a heat exchange assembly; the heat exchange assembly includes a first heat exchanger 3 and a second heat exchanger 4; the first heat exchanger 3 includes a gas flow chamber and a liquid flow chamber that are isolated from each other;

[0052] In this embodiment, the first heat exchanger 3 includes a housing 31 with openings at both ends and a heat exchange tube 32 that is bent multiple times in the middle; a plurality of evenly arranged fins 33 are attached to the outer surface of the heat exchange tube 32; in this embodiment, the fins 33 are L-shaped bent structures, and an arc angle is formed at the bent part; one side of the fins 33 is fixedly attached to the heat exchange tube 32, and the other side is attached to the adjacent fins 33 to form a back-to-back connection. The inner cavity of the heat exchange tube 32 forms the liquid flow chamber; the openings at both ends of the housing 31 and the gap 34 between the fins 33 form the gas flow chamber.

[0053] Due to production process limitations, the side of the existing fin 33 that fits the heat exchange tube 32 can have a maximum of 5 mm, otherwise it will affect the structural strength. If they are directly arranged in an array, the gap 34 between the fins 33 will be too small, that is, at most 5 mm, and the fibers carried in the exhaust gas are likely to block in the gap 34. By setting the fins 33 back to back, the gap 34 can be increased to about 10 mm without changing the structure of the fins 33, reducing the risk of fiber blockage.

[0054] In this embodiment, the first heat exchanger 3 is made of metal, and the second heat exchanger 4 has the same structure as the first heat exchanger 3.

[0055] The gas flow chamber includes an air inlet end 35 and an air outlet end 36. The air inlet end 35 is communicated with the air outlet 12, and the air outlet end 36 is communicated to the activated carbon adsorption device 5. After the activated carbon adsorption device 5, an induced draft fan 6 and a chimney 7 are successively connected. The activated carbon adsorption device 5 is used to remove harmful substances in the exhaust gas, including volatile organic compounds VOCs and other harmful gases, to achieve the purification and up-to-standard discharge of the exhaust gas. The main function of the induced draft fan 6 is to generate negative pressure to help extract and transport the gas treated by the activated carbon, ensure the continuity and stability of gas flow, and at the same time discharge the treated gas into the chimney 7 to achieve the high-altitude discharge of the exhaust gas.

[0056] The second heat exchanger 4 is arranged inside the drying oven 1; a pipeline 8 is connected between the second heat exchanger 4 and the liquid flow chamber to form a closed circulating water path; a circulating water pump 81 is provided on the pipeline 8; in this embodiment, an expansion tank 82 is also communicated with the pipeline 8 to stabilize the water pressure of the circulating water path.

[0057] The liquid flowing through the liquid flow chamber and the gas flowing through the gas flow chamber exchange heat through the first heat exchanger 3; the gas input into the drying oven 1 from the air inlet 11 exchanges heat with the liquid flowing through the second heat exchanger 4 through the second heat exchanger 4.

[0058] The printing substrate 9 is the paper towel or fabric to be printed, etc. These printing substrates 9 are controlled to move in the printing machine by the rollers 2.

[0059] The working principle is as follows: The drying oven 1 draws air, that is, gas, from the external environment through the air inlet 11. The gas passes through the rollers 2 and the printing substrate 9 on the rollers 2, takes away the moisture on the printing substrate 9 to dry the printing substrate 9, and at the same time absorbs the heat generated by the rollers 2, that is, forms hot and humid air, about 80 °C. The hot and humid air enters the gas flow chamber from the air outlet 12, absorbs heat from the liquid in the liquid flow chamber, and then is discharged to the external environment; at this time, the temperature of the liquid rises from about 40 °C to 65 °C, and the temperature of the discharged gas drops from 80 °C to about 45 °C.

[0060] After the liquid flowing through the liquid flow chamber absorbs heat, it is pumped by the circulation water pump 81 to the second heat exchanger 4. At this time, the gas entering the drying box 1 from the air inlet 11 absorbs the heat of the liquid through the second heat exchanger 4, and forms hot air blowing towards the printing medium 9; the hot air formed at this time is approximately 55 °C. The heat absorbed by the liquid is pumped back to the first heat exchanger 3 again.

[0061] Finally, the reuse of the discharged heat is realized, the utilization rate of the heat generated in the drying box 1 is improved, and the heat finally discharged into the environment is reduced.

[0062] Embodiment 2

[0063] This embodiment is as Figure 4 shown. For the features not explained in this embodiment, the explanations in Embodiment 1 are adopted and will not be elaborated here. The difference between this embodiment and Embodiment 1 is:

[0064] In this embodiment, there are multiple second heat exchangers 4, and they are evenly spaced; a first air chamber 13 is formed along the outer peripheral side of the multiple second heat exchangers 4; a second air chamber 14 is formed along the outer peripheral side of the multiple rollers 2; the first air chamber 13 and the second air chamber 14 are isolated from each other, and only one communication port 15 is provided;

[0065] The air inlet 11 is provided on the first air chamber 13, and the air outlet 12 is provided on the second air chamber 14. In this embodiment, the air inlet 11 and the communication port 15 are respectively provided at both ends of the first air chamber 13; the air outlet 12 and the communication port 15 are respectively provided at both ends of the second air chamber 14.

[0066] Setting two independent air chambers enables the air to fully exchange heat with the second heat exchanger 4 in the first air chamber 13, and then fully contact and dry the printing medium 9 in the second air chamber 14, improving the heat utilization effect.

[0067] According to the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A printing machine with a heat recovery device, comprising a drying box, wherein a plurality of rollers are arranged in the drying box, and the rollers are provided with heating units for drying the substrates passing through the rollers; characterized in that: The drying box is provided with an air inlet and an air outlet; The printing machine further comprises a heat exchange component; the heat exchange component comprises a first heat exchanger and a second heat exchanger; the first heat exchanger comprises a gas flow cavity and a liquid flow cavity which are isolated from each other; the gas flow cavity comprises an air inlet end and an air outlet end, the air inlet end is connected to the air outlet, and the air outlet end is connected to the external environment; the second heat exchanger is arranged inside the drying box; a pipeline is connected between the second heat exchanger and the liquid flow cavity to form a closed circulating water circuit; a circulating water pump is arranged on the pipeline; The liquid flowing through the liquid flow cavity and the gas flowing through the gas flow cavity exchange heat through the first heat exchanger; the gas input into the drying box from the air inlet and the liquid flowing through the second heat exchanger exchange heat through the second heat exchanger.

2. A printing machine with a heat recovery device according to claim 1, characterized in that: The first heat exchanger comprises a shell, the two ends of the shell are open, and one or more heat exchange tubes are arranged in the middle; the outer surface of the heat exchange tube is fitted with a plurality of evenly arranged fins; The inner cavity of the heat exchange tube forms the liquid flow cavity; the openings at both ends of the shell and the gaps between the fins form the gas flow cavity.

3. A printing machine with a heat recovery device according to claim 2, characterized in that: The fin is an L-shaped bending structure, and an arc angle is formed at the bending part; one side of the fin is fitted and fixed to the heat exchange tube, and the other side is fitted to the adjacent fin to form a back-to-back connection.

4. A printing machine with a heat recovery device according to claim 1, characterized in that: The first heat exchanger and the second heat exchanger are both made of metal.

5. The printing machine with a heat recovery device according to claim 1, characterized in that: There are a plurality of the second heat exchangers, which are evenly spaced; a first air cavity is formed along the outer periphery of the plurality of the second heat exchangers; a second air cavity is formed along the outer periphery of the plurality of the rollers; the first air cavity and the second air cavity are isolated from each other, and only one connecting port is provided; The air inlet is arranged on the first air cavity, and the air outlet is arranged on the second air cavity.

6. A printing machine with a heat recovery device according to claim 5, characterized in that: The air inlet and the communication port are respectively arranged at two ends of the first air cavity; the air outlet and the communication port are respectively arranged at two ends of the second air cavity.

7. The printing machine with a heat recovery device according to claim 1, characterized in that: The pipeline is also connected to an expansion water tank for stabilizing the water pressure of the circulating water circuit.

8. The printing machine with a heat recovery device according to claim 1, characterized in that: The air outlet end of the first heat exchanger is connected to the chimney.

9. A printing machine with a heat recovery device according to claim 8, characterized in that: An activated carbon adsorption device is arranged between the chimney and the gas outlet.

10. A printing machine with a heat recovery device according to claim 9, characterized in that: An induced draft fan is also provided between the activated carbon adsorption device and the chimney.

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