Drying device using an indirect infrared heating system

Abstract

A drying device (1) for drying a substance (2), comprising: a drum (3) rotatable about a central axis and having an outer peripheral surface (7) and an inner peripheral surface (5); and a belt (9) supported by the drum and having a first side and a second side (15, 17), the belt being adapted to receive the substance on the first side of the belt and, during operation, to urge the substance from the first side of the belt towards a part of the outer peripheral surface of the drum; and one or more infrared heating elements (8) arranged in proximity to and around a part of the inner peripheral surface for guiding radiant energy to the inner peripheral surface of the drum and thereby transferring heat by conduction to the substance urged between the belt and the drum.

Description

Technical Field

[0001]

[0001] The present invention relates to a drying device for drying substances, and more particularly to a drying device using an indirect infrared heating system.

Background Art

[0002]

[0002] The following description regarding the background of the present invention is only intended to facilitate the understanding of the present invention. It should be understood that the description is not a confirmation or approval that any of the materials mentioned were publicly known or part of the common general knowledge of those skilled in the art in any jurisdiction at the priority date of the present invention.

[0003]

[0003] The applicant sells a device for drying substances that uses a combination of heat and compression during the drying process. This is achieved by using a heated rotating drum supported by a belt around it in this drying device. The substance to be dried can be received by the belt, which can then bias the substance against the outer peripheral surface of the drum. The substance can then be subjected to both heating by heat conduction from the heated drum and compression when the substance is compressed between the belt and the drum. Currently, heat medium oil is used as the heat medium in this device.

[0004] However, there are significant drawbacks associated with the use of heat transfer oil as a heat medium. Heat transfer oil as a heat medium is not sustainable and poses a risk of environmental contamination due to undesirable heat transfer oil leakage, especially in a food environment. Not only do boilers or heaters occupy a significant amount of space, but there is also heat loss in the boiler due to the heat-insulating pipes between the boiler / heater and the dryer, and the flue gas from the boiler, leading to a decrease in energy efficiency due to heat loss. Furthermore, a large circulation pump or blower is required for the circulation of the heat medium, which contributes to substantial energy consumption. The working environment when using such a heating method is unpleasant at high temperatures, even while keeping the operating temperature relatively low. The additional space required for the auxiliary equipment of the external heat transfer oil boiler together with the external heat transfer oil boiler also makes the heat-insulating pipes and the boiler commissioning process difficult during the layout planning and installation.

[0005]

[0005] Furthermore, it takes several hours to heat the heat transfer oil from room temperature to the operating temperature in order to start production. It also takes several hours to cool down the system for maintenance and repair work. Therefore, a significant amount of energy and time are wasted waiting for the target temperature to be reached and proceeding to the next step, which is highly unproductive.

[0006]

[0006] An object of the present invention is to improve one or more of the above-mentioned difficulties associated with the heat medium used for conventional dryers.

Summary of the Invention

[0007]

[0007] According to one aspect of the present disclosure, a drum rotatable about a central axis and having an outer peripheral surface and an inner peripheral surface, a belt supported by the drum and having a first side and a second side, the belt being adapted to receive a substance on the first side of the belt and, during operation, urge the substance on the first side of the belt toward a part of the outer peripheral surface of the drum, a drying apparatus for drying a substance is provided, One or more infrared heating elements are disposed adjacent to and around a portion of the inner peripheral surface of the drum to direct radiant energy thereto and thereby transfer heat by conduction to a substance biased between the belt and the drum.

[0008]

[0008] In some embodiments, the drying apparatus further comprises one or more infrared heating elements disposed adjacent to and around a portion of the outer peripheral surface of the drum to direct radiant energy to the belt and thereby transfer heat by conduction to a substance being dried and biased between the belt and the drum.

[0009]

[0009] In some embodiments, one or more of the heating elements are in the form of a planar panel.

[0010]

[0010] In some embodiments, one or more of the heating elements are in the form of a curved panel.

[0011]

[0011] In some embodiments, the drum has a heating region to which heat can be supplied to the substance being dried, and the heating region has at least one heating zone.

[0012]

[0012] In some embodiments, the heating region has at least one non-heating zone to which no heat is supplied to the substance being dried.

[0013]

[0013] In some embodiments, the heating region comprises at least two heating zones, and heat is applied at different temperatures in each of the heating zones.

[0014]

[0014] In some embodiments, reflectors are provided on both sides of each infrared heating element to reflect radiant energy toward the drum.

[0015]

[0015] In some embodiments, the belt is porous.

[0016]

[0016] According to another aspect of the present disclosure, A drum that is rotatable about a central axis and has an outer peripheral surface and an inner peripheral surface, A belt supported by the drum and having a first side and a second side, the belt receiving a substance on the first side of the belt and being adapted to urge the substance on the first side of the belt toward a part of the outer peripheral surface of the drum during operation. A drying device for drying a substance is provided, comprising: One or more infrared heating elements are disposed adjacent to and around a part of the outer peripheral surface of the drum to direct radiant energy to the belt, thereby transferring heat by conduction to the substance being dried and urged between the belt and the drum.

[0017]

[0017] Upon consideration of the following description of specific embodiments in conjunction with the accompanying drawings, other aspects and features will become apparent to those skilled in the art.

[0018]

[0018] In the drawings, embodiments of the invention are shown by way of example only.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4a

Figure 4b

Figure 5a

Figure 5b

Figure 5c

Figure 6a

Figure 6b

DETAILED DESCRIPTION OF THE INVENTION

[0020]

[0025] Other arrangements of the present invention are also possible, and thus, the accompanying drawings should not be understood as substituting for the generality of the foregoing description of the present invention.

[0021]

[0026] Throughout this document, unless otherwise indicated to the contrary, terms such as "comprise," "consist of," "have," etc. should be construed as being non-exhaustive, or in other words, as meaning "including but not limited to."

[0022]

[0027] Furthermore, throughout this specification, unless the context otherwise requires, the word "include," or variations such as "includes" or "including," is understood to mean including the stated integer or group of integers, but not excluding any other integer or group of integers.

[0023]

[0028] Next, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to limit the scope of the present invention. Other definitions for the selected terms used in this specification can be found within the detailed description of the present invention and may apply throughout the description. Further, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. As far as possible, the same reference numbers are used throughout the figures for clarity and consistency.

[0024]

[0029] A drying apparatus for drying a substance according to the present disclosure applies heat and compression to the substance to be dried in a manner similar to the apparatus described above, using a rotary drum and a belt supported by the drum. However, the use of infrared heating elements obviates the need for a heat transfer medium such as thermal oil. A typical "direct" infrared dryer focuses radiant energy directly onto the substance. The vapor generated during the drying process occupies the space between the infrared heating element and the substance. Thus, in such a typical case, usually, ventilated air is required to remove the vapor, and as a result, some radiant energy is wasted on the unnecessary heating of the ventilated air and vapor.

[0025]

[0030] However, the drying apparatus according to the present disclosure uses "indirect" infrared heating of the substance, using one or more infrared heating elements to heat the drum and / or the belt using radiant energy, such that the substance is heated indirectly by heat conduction from the drum and / or the belt. The belt may preferably be porous, thereby enabling the moisture within the substance to evaporate and leak through the porous belt.

[0026]

[0031] [Fig. 1] shows an exemplary embodiment of a drying apparatus for drying a substance according to the present disclosure. The drying apparatus 1 includes a substantially cylindrical rotating drum 3 that is rotatable about a central axis and has an inner peripheral surface 5 and an outer peripheral surface 7. A continuous belt 9 having a first side 15 and a second side 17 is supported to move within the drying apparatus, and the belt 9 is supported by a series of rollers 11 and by the drum 3. A belt take-up roller 10 is used to press the second side 17 of the belt, thereby applying tension to the belt 9 such that the first side 15 of the belt is biased against the outer peripheral surface 7 of the drum as it passes through the drying apparatus 1. A feeder device 12 is used to feed the wet substance 2 onto the first side 15 of the belt. Thereafter, this wet substance 2 moves with the belt 9 and is pressed against the outer peripheral surface 7 of the drum. The drum 3 and the belt 9 may be made of either a metallic material or a non-metallic material. In comparison, a drying apparatus that uses heat transfer oil as a heat medium usually requires the drum to be made of metal.

[0027]

[0032] In the drying device 1 according to the present disclosure, one or more infrared heating elements 8 can be used. The embodiment shown in [FIG. 1] utilizes a series of infrared heating elements 8 arranged close to the inner peripheral surface 5 of the drum in the embodiment of the drying device shown in [FIG. 1]. Each infrared heating element 8 can be powered by electricity or by a gas such as natural gas, propane gas, biogas, synthesis gas or hydrogen when there is no fire. The infrared heating element 8 generates concentrated radiant energy that can be directed in a very focused manner, in the same way as light, towards a specific region of the inner peripheral surface 5 of the drum. The drum 3 blocks and absorbs the radiant energy without interposing a heat medium such as air and / or liquid between the drum and the infrared heating element 8, and converts that energy into heat. Thus, energy loss is reduced by eliminating the need to heat the heat medium and / or the surroundings. Then, when the wet material 2 is biased against the outer peripheral surface 7 of the drum, heat is applied to the wet material 2 by heat conduction through the wall of the drum 3. Thus, the wet material 2 is dried using both heat and compression within the device. Thus, the drying device 1 utilizes an "indirect" infrared system because the infrared heating element 8 does not directly focus the radiant energy of the infrared heating element 8 onto the wet material 2 as in the case of a conventional infrared dryer. The moisture evaporated from the wet material 2 when the wet material 2 is dried is removed from the drying device 1 through a hood 23 provided above the drum 3. The belt 9 may be porous in order to allow the moisture evaporated through the porous belt 9 to escape. Then, the final dried product 6 is scraped off the belt 9 by a belt scraper 21, falls onto the output conveyor 18 and is discharged from the drying device. A drum scraper 16 is also used to remove the remaining dried product 6 from the outer peripheral surface 7 of the drum, and the remaining dried product 6 may also fall onto the output conveyor 18. Then, the belt 9 is cleaned by using a belt cleaning brush 19 to brush off the remaining dried product 6 from the first side of the belt.

[0028]

[0033] The embodiment of the drying device 1 shown in [Fig. 1] has an infrared heating element 8 disposed in the drum 3 in proximity to the inner peripheral surface 5 of the drum. In another embodiment of the drying device according to the present disclosure, as shown in [Fig. 2], the infrared heating element 8a can be disposed outside the drum 3 in proximity to the belt 9 when the belt 9 is supported by the drum 3. In this arrangement, a part of the radiant energy is absorbed by the belt 9, a part of the radiant energy is transmitted through the belt 9, and is directly absorbed by the wet material 2. A part of the radiant energy absorbed by the belt 9 is converted into heat and transmitted to the wet material 2 by heat conduction. A part of the radiant energy is transmitted through the belt 9, directly absorbed by the wet material 2, converted into heat, and evaporates the internal moisture.

[0029]

[0034] [Fig. 3] shows a further embodiment of the drying device according to the present disclosure, in which a series of heating elements 8, 8a are respectively disposed inside the drum 3 in proximity to the inner peripheral surface 7 of the drum, and outside the drum 3 in proximity to the belt 9 when the belt 9 is supported by the drum 3. In this arrangement, the wet material 2 receives heat from both the drum 3 and the belt 9, as well as by direct absorption of radiant energy, and thus it becomes possible to feed a thicker layer of the wet material 2 onto the belt 9, thereby enhancing the production capacity or throughput of the dryer.

[0030]

[0035] The embodiment of the drying device 1 shown previously in [Figs. 1 - 3] and also shown in [Fig. 4a] shows infrared heating elements 8, 8a in the form of flat panels. However, depending on the degree of customization to the drum curvature, it is also envisaged that infrared heating elements 8b in the form of curved panels are used. The aim is to maintain a uniform and as short as possible gap between the surface of the curved infrared heating element 8b and the inner peripheral surface 5 of the drum. This is aimed at enhancing the heat transfer efficiency and improving the heat distribution as much as possible.

[0031]

[0036] The drum 3 may have a heating region 29 where heat can be supplied to the moist substance 2 during drying. As shown in [Fig. 5a], the heating region 29 can comprise a single heating zone 30 where heat is applied at a uniform temperature inside the entire heating region 29 of the drum 3. However, if the heating region 29 of the drum 3 is divided into two or more zones, improvement of the final dried product 6 can be obtained and / or the heating time of the moist substance 2 can be shortened. [Fig. 5b] shows an arrangement where the heating region is divided into a heating zone 32 and a smaller non-heating zone 34 where no heat is applied. [Fig. 5c] shows an arrangement where the heating region 29 is divided into two heating zones 36, 38 which are similar regions and a smaller non-heating zone 34. One of the heating zones 36 may have a higher operating temperature to promote moisture evaporation from the moist substance 2. In that case, the water content of the moist substance 2 would potentially decrease and the temperature of the moist substance would have risen before entering the second heating zone 38 which has a lower operating temperature to continue the heating process. Thereby, while reducing the overall energy consumption and increasing the throughput, a better quality of the dried article is ensured.

[0032]

[0037] As shown in [Figs. 6a and 6b], in a further exemplary embodiment of the drying apparatus 1 according to the present disclosure, two reflectors 25 made of polished metal and having a substantially annular shape are installed on both sides of the infrared heating element 8 that supplies radiant energy 26 directly to the drum 3, and the reflectors 25 serve to change the direction of the edge-loss radiant energy 28 and return it to the drum 3. This can help to increase the energy efficiency and keep the side walls and the surrounding area of the drum at a low temperature. Similar reflectors can also be used together with the infrared heating elements located outside the drum 3 to change the direction of the edge-loss radiant energy and return it to the belt 9.

[0033]

[0038] The drying apparatus according to the present disclosure can be used in the food industry / food ingredient industry for human consumption or animal feed, which has processes that require dried products that retain the following: nutritional value, sensory stimulation characteristics, and calorie value.

[0034]

[0039] Fishery processing

[0035]

[0040] Fishery processing facilities can attempt to transform fish scraps into healthy, fragrant, and highly nutritious food ingredients / recipe components, enhance nutrition and flavor, and upcycle the scraps into highly profitable consumer products.

[0036]

[0041] The aquaculture industry in fish / shrimp feed production has been gradually moving away from natural feed for some time, recognizing the need to produce highly nutritious fish feed while increasing productivity, enhancing resilience to climate change, and overcoming resource constraints.

[0037]

[0042] Dried fish scraps are also extremely attractive ingredients to incorporate into pet food to enhance aroma, flavor, and most importantly, nutrition.

[0038]

[0043] Agriculture

[0039]

[0044] As more people are interested in healthier snacks / food ingredients, dried fruit and vegetable products are gaining popularity. The cost of dried fruits or vegetables is high, mainly due to high manufacturing costs. The challenges lie in maintaining taste, flavor, color, and texture during production, and the available technologies to achieve these standards. Fruit and vegetable powders can be used in beverages, cooking, and garnishes.

[0040]

[0045] Plant-based food processing factories may dry unappealing or unsold fruits / vegetables, or even fresh crops. With specific temperature control, most of the desired nutrients can be retained in dried form and used as food ingredients or animal / aquatic feed.

[0041]

[0046] Pet owners also proactively purchase high-quality dried fruit and vegetable products for their animals in an attempt to incorporate excellent nutrition into their pets' diets.

[0047] Meat processing

[0048] Food processing operations such as meat, poultry, or seafood processing plants generate large amounts of nutrient-rich organic by-streams. The present invention converts these by-streams into products containing high levels of protein and minerals.

[0042]

[0049] By using an infrared heating element instead of heat transfer oil as a heat source, carbon dioxide emissions are reduced, a more energy-efficient drying method is created, and productivity is increased. Also, by using an infrared heating system instead of heat transfer oil, an external boiler, insulated piping, and other auxiliary equipment related to heat transfer oil are not required, leading to space savings. Therefore, the installed drying device according to the present disclosure may occupy a fairly small space. Due to the low thermal inertia of infrared radiation heating, the preheating time can be shortened, and it usually takes less than 10 minutes to reach the operating temperature. In comparison, it may take several hours to heat the heat transfer oil from room temperature to the operating temperature to start production. It also takes several hours to cool the system for maintenance and repair work. Therefore, a significant amount of energy and time are wasted waiting for the target temperature to be achieved and proceeding to the next step, which is highly unproductive. Fuel gas (LNG, LPG) is much lower in unit cost compared to electricity, so many locations or countries prefer the use of fuel gas (LNG, LPG). Therefore, the use of an infrared heating element can lead to a reduction in operating costs. The cost reduction is particularly significant in high-volume drying applications. Furthermore, the infrared heating element is preferably arranged inside the drum and can heat the inner circumferential surface intensively and directly, so the energy lost by heating the air or the surroundings is minimized.

[0043]

[0050] By using a new indirect heating method in the drying device according to the present disclosure, the synthesis gas generated during the gasification process can be directly supplied to the infrared heating element, which may also enable the development of more efficient waste to energy utilization. This is in contrast to a dryer that requires heat transfer oil as a heat medium. In the new indirect heating method according to the present disclosure, the need to heat the heat transfer oil in the external boiler using synthesis gas can be eliminated before circulating the high-temperature heat transfer oil through the heating drum.

[0044]

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of this specification belongs.

[0045]

[0052] It should be understood by those skilled in the art that the above invention is not limited to the described embodiments. It is recognized that modifications and improvements can be made without departing from the scope of the present invention.

[0046]

[0053] It should be further understood by those skilled in the art that one or more of the above modifications or improvements, which are not mutually exclusive, can be further combined to form additional embodiments of the present invention.

Claims

1. A drum rotatable about a central axis and having an outer peripheral surface and an inner peripheral surface, A belt supported by the drum and having a first side and a second side, the belt receiving a substance on the first side thereof and being adapted to urge the substance on the first side thereof toward a part of the outer peripheral surface of the drum during operation, A drying apparatus for drying a substance, comprising: One or more infrared heating elements are disposed adjacent to and around a part of the inner peripheral surface to conduct radiant energy to the inner peripheral surface of the drum, thereby transferring heat by conduction to the substance urged between the belt and the drum.

2. The drying apparatus according to claim 1, further comprising one or more infrared heating elements disposed adjacent to and around a part of the outer peripheral surface of the drum to conduct radiant energy to the belt, thereby transferring heat by conduction to the substance urged between the belt and the drum.

3. The drying apparatus according to claim 1 or 2, wherein the one or more heating elements are in the form of a planar panel.

4. The drying apparatus according to claim 1 or 2, wherein the one or more heating elements are in the form of a curved panel.

5. The drying apparatus according to any one of claims 1 to 4, wherein the drum has a heating region to which heat can be supplied to the substance being dried, and the heating region has at least one heating zone.

6. The drying apparatus according to claim 5, wherein the heating region has at least one non-heating zone to which no heat is supplied to the substance being dried.

7. The drying apparatus according to claim 5 or 6, wherein the heating region comprises at least two heating zones, and heat is applied at different temperatures in each of the heating zones.

8. The drying apparatus according to any one of claims 1 to 7, wherein reflectors are provided on both sides of each infrared heating element to reflect radiant energy toward the drum.

9. The drying apparatus according to any one of claims 1 to 8, wherein the belt is porous.

10. A drying apparatus for drying a substance, comprising: a drum rotatable about a central axis and having an outer peripheral surface and an inner peripheral surface; a belt supported by the drum and having a first side and a second side, the belt being adapted to receive the substance on the first side of the belt and to urge the substance on the first side of the belt toward a part of the outer peripheral surface of the drum during operation; and one or more infrared heating elements are disposed adjacent to and around a part of the outer peripheral surface of the drum to direct radiant energy to the belt and thereby transfer heat by conduction to the substance being dried and urged between the belt and the drum.

11. The drying apparatus according to claim 10, wherein the one or more heating elements are in the form of a planar panel.

12. The drying apparatus according to claim 10, wherein the one or more heating elements are in the form of a curved panel.

13. The drying apparatus according to any one of claims 10 to 12, wherein the drum has a heating region in which heat can be supplied to the substance being dried, and the heating region has at least one heating zone.

14. The drying apparatus according to claim 13, wherein the heating region has at least one non-heating zone in which heat is not supplied to the substance being dried.

15. The drying device according to claim 13 or 14, wherein the heating area includes at least two heating zones, and heat is applied at different temperatures in each of the heating zones.

16. The drying device according to any one of claims 10 to 15, wherein reflectors are provided on both sides of each infrared heating element to reflect radiant energy toward the drum.

17. The drying device according to any one of claims 10 to 16, wherein the belt is porous.

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