Dual heat source tea roasting and aroma enhancing device

Abstract

The utility model discloses a kind of tea baking aroma extraction devices of double heat source, the tea baking aroma extraction device of this double heat source includes box, the top of the box is equipped with fresh air input equipment, regenerator, electric heater, circulating fan, temperature and humidity monitoring instrument and airflow control valve, the left and right two side inner walls in the box interior each install one far infrared heater and its corresponding graphene baffle. The baffle of graphene material is selected to block far infrared light, only allow part of frequency band far infrared wave to penetrate to heat tea, simultaneously adopt circulating air and multiple air outlets even air supply combination, improve the temperature control precision of tea baking aroma extraction, it is beneficial to the aroma of tea, the advantage that comprehensively utilizes hot air heating and far infrared heating aroma extraction also makes tea aroma rich, level rich.

Description

Technical Field

[0001] This utility model belongs to the field of tea processing technology, specifically relating to a dual-heat-source tea roasting and aroma-enhancing device and its operating method. Background Technology

[0002] The primary processing of black tea mainly includes withering, rolling, fermentation, and drying, while the refining process mainly includes aroma enhancement, winnowing, and blending. Withering is generally the foundation for aroma formation in black tea, rolling and fermentation are key to aroma development, and drying and aroma enhancement are important steps in aroma quality. Drying is the final step in the primary processing of black tea; high temperatures rapidly deactivate enzymes, terminating enzymatic reactions, fixing the quality characteristics of the tea, reducing moisture content, and facilitating tea storage. Currently, research on the various processing stages of black tea mainly focuses on withering, fermentation, and drying. There are three main methods for enhancing the aroma of tea: roasting, pan-frying, and far-infrared roasting, with roasting being the most widely used. Roasting typically refers to using heat conduction through convection, such as roasting tea leaves in a hot air oven. Besides the method of aroma enhancement, factors affecting the effect include temperature, time, initial moisture content of the tea leaves, and the rate of temperature rise.

[0003] During the roasting and aroma-enhancing process, tea leaves undergo complex thermochemical reactions, such as the Maillard reaction and caramelization, resulting in changes to the tea's structural components and even the formation of new substances. This enhances the aroma and further improves the tea's quality. The leaf temperature is controlled below 130℃ during tea processing, thus the Maillard reaction is the dominant process. Tea contains a large amount of free amino acids and sugars, which are important flavor compounds and precursors to Maillard products such as pyrazines and furfural derivatives. Increasing the temperature during roasting promotes the Maillard reaction, enhancing the aroma and producing roasted, sweet, and caramel notes. However, excessive temperature can produce a burnt aroma. Therefore, the temperature, humidity, and duration of tea roasting play a crucial role in the quality of the tea.

[0004] Although roasting is widely used for aroma enhancement, research on how the selection of parameters for optimizing the roasting and aroma enhancement process affects the aroma and quality of black tea is relatively scarce. Most current aroma-enhancing and re-roasting machines use a single-pipe air supply, resulting in uneven airflow within the roaster. This leads to inconsistent surface temperature and humidity of the tea leaves, resulting in low-quality roasted tea. Single-heat-source temperature control has a lag; whether using electric heaters or far-infrared heating, the lag in heat transfer causes a delay in temperature control. Generally, to prevent overheating, the temperature is controlled prematurely, leading to insufficient localized temperatures and reduced tea quality. Far-infrared heating has been proven effective for aroma enhancement, but far-infrared heating through quartz glass can damage certain components, resulting in insufficient aroma enhancement. Therefore, there is an urgent need to research suitable far-infrared heating wavelengths and frequency bands for tea aroma enhancement. Relying solely on temperature control results in unstable temperatures within the roasting chamber and low precision control, which is detrimental to the richness of the tea's aroma layers. Current tea roasting methods also do not consider energy efficiency: heat is often directly released into the environment, resulting in resource waste.

[0005] Based on the above background, it is necessary to further study the specific impact of roasting and aroma-enhancing process parameters on the quality of tea roasting, and to design an operating device that can implement the determined roasting and aroma-enhancing process parameters in the actual tea roasting process. Utility Model Content

[0006] To address the aforementioned technical issues, the applicant provides a technical solution that combines roasting and far-infrared aroma enhancement. This solution utilizes graphene material baffles to block far-infrared light, allowing only certain frequency bands of far-infrared waves to pass through and heat the tea leaves. Simultaneously, it employs a combination of circulating air and multiple air outlets for uniform air delivery. The specific details are as follows:

[0007] The applicant proposed a tea roasting and aroma enhancement device using dual heat sources to roast and enhance the aroma of tea. The tea roasting and aroma enhancement device includes a box, the top of which is equipped with a fresh air input device, a regenerator, an electric heater, a circulating fan, and an airflow guiding control valve. A far-infrared heater and its corresponding graphene baffle are installed on the inner walls of the left and right sides of the box.

[0008] The housing also has a multi-layered support structure, which is a hollow support tube. The support tube is a hollow pipe that is connected or coiled on the same plane. The support tube can be disc-shaped or rectangular as needed. The support tube is used to place the tea tray. An air inlet pipe is connected between the support tube and the circulating fan, and an air outlet pipe is connected between the support tube and the fluid control valve. Multiple ventilation holes are evenly opened on the outer periphery of the support tube. The circulating fan delivers hot air (heated / unheated by the electric heater) to the support tube through the air inlet pipe. The hot air heats the tea in the tray placed on the support tube through the ventilation holes on the outer periphery of the support tube. The airflow flows through the air outlet pipe past the temperature and humidity monitor, the airflow guide control valve, and / or through / without the fresh air input device and the regenerator.

[0009] The wavelength range of the far-infrared light output by the far-infrared heater after being blocked by the graphene baffle is 10μm to 15μm.

[0010] The pipes connecting the fresh air input device, airflow guiding control valve, regenerator, heater, circulating fan, and support pipe are all hollow pipes.

[0011] A touchscreen controller is installed on the side or top of the cabinet door panel. This controller is used to set and adjust parameters, and directly displays real-time temperature and humidity data, as well as record process curves. The parameters include the heating temperature, humidity, and heating time inside the cabinet. Multiple temperature and humidity acquisition devices are also installed inside the cabinet. Temperature and humidity monitors are installed on the top, front, or side of the cabinet for easy monitoring of the operating temperature inside. The controller is electrically connected to the temperature and humidity acquisition devices and monitors, together forming the temperature and humidity control system of this dual-heat-source tea roasting and aroma-enhancing device.

[0012] The specific operation method of the dual-heat-source tea roasting and aroma-enhancing device includes: after starting the dual-heat-source tea roasting and aroma-enhancing device, the circulating fan starts, and the electric heater and far-infrared heater are simultaneously turned on for heating. The hot air generated by the electric heater is transported to the support pipe inside the chamber through the circulating fan. The airflow heats the tea tray through multiple evenly distributed ventilation holes on the support pipe. The circulated gas is then transported sequentially to the temperature and humidity monitor and airflow control valve outside the chamber through the exhaust pipe. When the humidity exceeds the set value, the control valve opens and the fresh air input device starts. The airflow connects with the regenerator channel to expel moisture and exchanges heat with the fresh air. It is then transported to the heater and then transported to the air supply pipe into the chamber through the circulating fan. When the humidity is lower than the set value, the control valve closes and the airflow flows directly through the heater and re-enters the circulation.

[0013] The chamber is equipped with multiple collection points to collect parameters such as heating temperature, humidity and heating time of the tea leaves, with temperature fluctuations controlled within ±1℃.

[0014] The temperature control method of this dual-heat-source tea roasting and aroma-enhancing device specifically includes: depending on the type of tea, when the heating rate reaches a set value (range 0.5℃ / min-0.8℃ / min), the electric heater stops operating, and only the far-infrared heater operates. Depending on the type of tea, when the temperature reaches the set temperature T1, both heaters stop operating. When the temperature of the airflow inside the chamber is more than 1℃ lower than the set temperature, the electric heating and far-infrared heater operate simultaneously. During heating and dehumidification, both heat sources operate simultaneously; during temperature maintenance, the heaters either do not operate or only one heater operates.

[0015] This application uses a dual heat source combination to improve the accuracy of temperature and humidity control, and comprehensively utilizes the advantages of hot air heating and far-infrared heating to enhance aroma, resulting in a richer aroma profile for the tea.

[0016] Hot air circulation heating primarily heats the surface of an object. Since there's a temperature difference between the inside and outside, when the surface reaches the set temperature, some parts of the interior may not. This affects the thermal conversion of aroma compounds within the tea leaves, hindering the enhancement of aroma and flavor. Generally, increasing the heating temperature can improve aroma and flavor, but excessively high temperatures can also negatively impact the surface conversion of the tea leaves. Therefore, low-temperature slow roasting is preferred, using a lower temperature and longer heating time. This aligns with the low-temperature slow roasting of tobacco and represents a current trend in tea roasting for aroma enhancement. However, for tea, precise temperature control has a significant impact on quality. The magnitude and rate of temperature increase both significantly affect product quality; excessively long roasting times will noticeably degrade tea quality.

[0017] Based on this, the applicant proposes that during the initial heating phase, both electric heating and far-infrared heating be activated simultaneously, ensuring that the surface and interior of the tea leaves reach the set temperature at the same time. Then, only hot air circulation is used to enter a low-temperature heating mode. When the temperature drops slightly below the set temperature, a weak heat supplement is applied, at which point only one heater needs to be activated. This method efficiently heats the tea leaves rapidly from the inside out, reducing the temperature difference between the inside and outside of the tea. It also allows for hot air circulation to supplement energy, achieving both aroma enhancement and energy saving, thus contributing to the stability of tea quality.

[0018] Using graphene blocking plates to select the frequency and wavelength of far-infrared light transmission: By using graphene to block light frequencies that are detrimental to the aroma enhancement of tea, the aroma-enhancing effect of far-infrared heating on tea can be optimized. Within the frequency and wavelength range of far-infrared heating, some frequencies are unfavorable for the aroma conversion of tea. Therefore, selecting suitable materials to block these unfavorable frequencies is a feasible solution. Experiments have shown that after graphene blocking, far-infrared light in the wavelength range of 10μm to 15μm can still enhance tea aroma without affecting color, and has a superior aroma-enhancing effect. Specifically, after graphene blocking, because graphene can block some far-infrared light frequencies, it is more beneficial for controlling the color and enhancing the aroma of tea, resulting in bright tea color and rich aroma. In contrast, far-infrared heating blocked by quartz plates will change some beneficial components of tea, resulting in a darker, blacker tea color and significant aroma loss.

[0019] In some examples, the shield can also be made of other materials that can transmit far-infrared rays in the 10μm to 15μm wavelength range. In the baking of ingredients such as tea, food safety is the primary consideration; therefore, it is essential to ensure that the selected materials are non-toxic and harmless, do not release harmful substances, and meet food contact safety standards; they must be heat-resistant and stable, not decomposing or deteriorating at 130°C; and they must not chemically react with the food, such as by not absorbing odors or catalyzing spoilage. Therefore, food-grade modified polyimide (PI) film can be optionally used. Food-grade polyimide can be commercially available DuPont Kapton® FN or similar certified products, conforming to FDA 21 CFR 177.2450 (permitted for use in food contact materials), capable of withstanding temperatures above 200°C, and not releasing harmful substances, and is oil-resistant, water-resistant, and anti-aging.

[0020] In some examples, food-grade alumina ceramics are used to construct the far-infrared heaters or cavities of tea roasting and aroma-enhancing devices. Food-grade alumina ceramics, such as high-purity alumina ceramics (99.5% Al2O3), meet FDA and LFGB (German food-grade standards) certifications, do not release heavy metals (such as lead and cadmium), are heat-resistant (>1600℃), and are stable over long-term use. From a cost perspective, food-grade alumina ceramics are relatively inexpensive, offering the best cost-performance ratio and making them suitable for mainstream tea roasting devices.

[0021] Circulating air is delivered into the tea tray support duct to heat the tea leaves. When the moisture content of the tea leaves exceeds a set value, it connects to the regenerator channel to expel moisture. Simultaneously, fresh air enters and exchanges heat with the exhaust airflow to recover heat before entering the heater and being circulated into the chamber by a fan. When the moisture content of the circulating airflow falls below the set value, the fresh air supply stops, and a switching valve directs the airflow into the heater, entering circulation mode. Direct exhaust and intake airflow have a large temperature and humidity difference with the tea leaves, which can lead to undesirable transformations. With regenerator, the temperature of the incoming fresh airflow is increased, while its relative humidity is reduced. This reduces the temperature and humidity difference between the airflow and the tea leaves, achieving gentle heating. This is beneficial for enhancing the aroma and flavor of the tea and improving its quality. After dehumidification, because fresh air is introduced, to reduce the temperature and humidity differences between the fresh air and the tea leaves, electric heating and far-infrared heating operate simultaneously to ensure a rapid temperature rise or control temperature fluctuations below ±1℃. The temperature rise rate and the time to reach a specific temperature are set according to the specific tea roasting process for different tea varieties.

[0022] By changing the single-orifice air supply mode of the air supply channel to a multi-orifice air supply mode with multiple ventilation holes on the outer periphery of the ventilation duct of the support device, uniform air supply heating is achieved, resulting in uniform heating of the tea during roasting and improved aroma quality. By delivering circulating air to multiple air outlets under the tray, uniform temperature across each layer and uniform heating of the tea leaves on each support frame are ensured. From a fluid dynamics perspective, multi-point uniform air supply provides significantly better uniformity than single-pipe, single-orifice air supply. Fluid flow follows Bernoulli's equation, and uniform flow can be achieved during heating by optimizing the flow structure and air supply points. This can also be optimized through CFD simulation using fluid dynamics software. Therefore, using multi-orifice air supply from annular or rectangular ducts under the tea tray is beneficial for achieving uniform fluid flow.

[0023] Using a touchscreen controller or a simple digital display controller, parameters such as temperature, humidity, and heating time at the data acquisition points can be easily set and adjusted. The real-time status of the parameters is displayed digitally, and the process curve is recorded. The process parameters collected at the data acquisition points can be selected according to actual needs. Multiple temperature and humidity data acquisition points can be set, or one data acquisition point can be set at the top and one at the bottom, or three data acquisition points can be set at the top, middle, and bottom.

[0024] This application adopts a dual heat source combination control to improve the temperature control accuracy for tea roasting and aroma enhancement, which is beneficial to the aroma enhancement of tea. The comprehensive use of the advantages of hot air heating and far-infrared heating for aroma enhancement also makes the tea aroma rich and layered. Attached Figure Description

[0025] Figure 1 A schematic diagram of the main structure of the dual-heat-source tea roasting and aroma-enhancing device for an embodiment;

[0026] Figure 2 A schematic diagram showing the layout of the circular support pipe and air outlet;

[0027] Figure 3 This is a schematic diagram of the circulating gas flow.

[0028] Figure 4 A schematic diagram of the rectangular structure of the support pipe and the air outlet;

[0029] Figure 5 A schematic diagram of the main structure of a dual-heat-source tea roasting and aroma-enhancing device for comparison.

[0030] In the diagram, 1-box body, 2-regenerator, 3-electric heater, 4-circulating fan, 5-far-infrared heater, 6-graphene shield, 7-support structure, 701-ventilation hole, 8-touch screen controller, 9-quartz shield. Detailed Implementation

[0031] The utility model will now be further described in conjunction with the accompanying drawings and specific embodiments. For the sake of brevity, only the parts relevant to the disclosure are schematically shown in each drawing; they do not represent the actual structure of the product. Furthermore, for the sake of clarity and ease of understanding, in some drawings, only one of the components with the same structure or function is schematically shown, or only one is labeled. In this document, "a" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0032] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0033] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0035] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] Example 1

[0037] The following is passed Figures 1 to 3 This application demonstrates a dual-heat-source tea roasting and aroma-enhancing device.

[0038] See Figure 1 , Figure 1 This application discloses a dual-heat-source tea roasting and aroma-enhancing device. The device includes a housing 1, with a fresh air input device (not shown in the figure), a regenerator 2, an electric heater 3, a circulating fan 4, and an airflow guiding control valve (not shown in the figure) installed on the top of the housing 1. A far-infrared heater 5 and its corresponding graphene baffle 6 are installed on each of the left and right inner walls of the housing 1. The housing 1 also has a multi-layer support structure 7. The far-infrared light output by the far-infrared heaters after being blocked by the graphene baffles has a wavelength range of 10μm to 15μm.

[0039] See Figure 2 , Figure 2 This is a schematic diagram of the multi-layer support structure 7 in the dual-heat-source tea roasting and aroma-enhancing device of this application. The support structure is a hollow support tube, which is a hollow pipe on the same plane by means of connection or coiling. The support tube is disc-shaped and is used to place the tea tray. An air inlet pipe is connected between the support tube and the circulating fan 4, and an air outlet pipe is connected between the support tube and the gas guiding control valve. Multiple ventilation holes 701 are evenly opened on the outer periphery of the support tube.

[0040] See Figure 3 , Figure 3 This is a schematic diagram of the circulating gas flow in the dual-heat-source tea roasting and aroma-enhancing device of this application. The circulating fan 4 delivers hot air heated by the electric heater 3 to the support pipe through the air inlet duct. The hot air heats the tea leaves placed on the tray on the support pipe through the ventilation holes 701 on the outer periphery of the support pipe. The airflow then flows through the air outlet duct past the humidity monitor, the airflow guidance control valve, and the fresh air input device or regenerator 2. The pipes connecting the fresh air input device, the airflow guidance control valve, the regenerator 2, the heater 3, the circulating fan 4, and the support pipe are all hollow pipes.

[0041] A touchscreen controller 8 is installed on the door panel of the enclosure 1. The controller 8 is used to set and adjust parameters, and digitally displays the real-time temperature and humidity status, as well as record the process curves. The parameters include the heating temperature, humidity, and heating time inside the enclosure 1. Multiple temperature and humidity acquisition devices 9 are also installed inside the enclosure 1, respectively located in the upper, middle, and lower parts. Temperature and humidity monitors are installed on the top, front, or side of the enclosure 1 to facilitate monitoring of the operating temperature inside the enclosure. The controller 8 is electrically connected to the temperature and humidity acquisition devices 9 and the temperature and humidity monitors, together forming the temperature and humidity control system of this dual-heat-source tea roasting and aroma-enhancing device.

[0042] In this embodiment, the operation method of the dual-heat-source tea roasting and aroma-enhancing device specifically includes: after starting the dual-heat-source tea roasting and aroma-enhancing device, the circulating fan 4 is started, and the electric heater 3 and the far-infrared heater 5 are simultaneously turned on for heating. The hot air generated by the electric heater 3 is transported to the support pipe inside the housing 1 through the circulating fan 4. The airflow heats the tea tray through multiple evenly distributed vents 701 on the support pipe. The circulated gas is sequentially transported to the temperature and humidity monitor and the airflow guiding control valve outside the housing 1 through the exhaust pipe. When the humidity exceeds the set value, the control valve is opened and the fresh air input device is started. The airflow is connected to the channel of the regenerator 2 to discharge the moisture and then exchanges heat with the fresh air to recover heat. Subsequently, it is transported to the heater 3, and then the airflow is transported to the air supply pipe and enters the housing 1 through the circulating fan 4. When the humidity is lower than the set value, the control valve is closed, and the airflow flows directly through the heater 3 and re-enters the circulation.

[0043] Multiple collection points are set inside the chamber 1 to collect parameters such as heating temperature, humidity and heating time of tea leaves, with temperature fluctuation controlled within ±1℃.

[0044] The temperature control method of this dual-heat-source tea roasting and aroma-enhancing device specifically includes: depending on the type of tea, when the heating rate reaches 0.5℃ / min, the electric heater 3 stops operating, and only the far-infrared heater 5 operates. When the temperature reaches the set temperature T1, both heaters stop operating. When the temperature drops below the set temperature by 1℃, the electric heater 3 is activated to supplement the heat. When the humidity of the airflow exceeds the set value (specific value) or the temperature drops below the set temperature by more than 1℃, the electric heater 3 and the far-infrared heater 5 operate simultaneously. During the heating and dehumidification processes, both heat sources operate simultaneously; during temperature maintenance, the heaters either do not operate or only one heater operates.

[0045] The graphene blocking plate 6 is used to select the frequency and wavelength of far-infrared light transmission: The graphene blocking plate 6 blocks light frequencies that are detrimental to the aroma enhancement of tea, thus optimizing the aroma-enhancing effect of far-infrared heating. Within the frequency and wavelength range of far-infrared heating, some frequencies are unfavorable for aroma conversion in tea. Therefore, selecting suitable materials to block these unfavorable frequencies is a feasible solution, with infrared light between 10μm and 15μm being preferred for heating the tea. After graphene blocking, because graphene can intercept some far-infrared light frequencies, it is more beneficial for controlling the color and enhancing the aroma of the tea. The roasted tea has a bright color, rich aroma, a polyphenol retention rate >88%, and an amino acid loss <10%.

[0046] Example 2

[0047] The following is passed Figure 1 and Figure 3-4 This application demonstrates a dual-heat-source tea roasting and aroma-enhancing device.

[0048] See Figure 1 and Figure 4 , Figure 1 This application discloses a dual-heat-source tea roasting and aroma-enhancing device. Figure 4 yes Figure 1 The dual-heat-source tea roasting and aroma-enhancing device has a multi-layered support structure 7 inside its housing 1. This support structure is a hollow support tube, which is a hollow pipe that is connected or coiled on the same plane. The support tube is rectangular and is used to place the tea tray. An air inlet pipe is connected between the support tube and the circulating fan 4, and an air outlet pipe is connected between the support tube and the fluid guiding control valve. Multiple ventilation openings 701 are evenly distributed on the outer periphery of the support tube.

[0049] like Figure 3 As shown, the circulating fan 4 delivers the hot air heated by the electric heater 3 to the support pipe through the air inlet duct. The hot air heats the tea leaves placed on the tray on the support pipe through the ventilation holes 701 on the outer periphery of the support pipe. Then, the airflow flows through the air outlet duct, passing through the humidity monitor, the airflow guidance control valve, and the fresh air input device or regenerator 2. The pipes connecting the fresh air input device, the airflow guidance control valve, the regenerator 2, the heater 3, the circulating fan 4, and the support pipe are all hollow pipes.

[0050] A touchscreen controller is installed on the door panel of the chamber 1. This controller is used to set and adjust parameters, and digitally display the real-time temperature and humidity status, as well as record the process curves. The parameters include the heating temperature, humidity, and heating time inside the chamber. Multiple temperature and humidity acquisition devices are also installed inside the chamber 1, located at the top and bottom. Temperature and humidity monitors are installed on the top, front, or side of the chamber 1 to facilitate monitoring of the operating temperature inside the chamber. The controller 8 is electrically connected to the temperature and humidity acquisition devices 9 and the temperature and humidity monitors, together forming the temperature and humidity control system of this dual-heat-source tea roasting and aroma-enhancing device.

[0051] The specific operation method of the dual-heat-source tea roasting and aroma-enhancing device includes: after starting the dual-heat-source tea roasting and aroma-enhancing device, the circulating fan 4 starts, and the electric heater 3 and the far-infrared heater 5 are simultaneously turned on for heating. The hot air generated by the electric heater 3 is transported to the support pipe inside the box 1 through the circulating fan 4. The airflow heats the tea tray through multiple evenly distributed ventilation holes 701 on the support pipe. The circulated gas is sequentially transported to the temperature and humidity monitor and the airflow guide control valve outside the box 1 through the exhaust pipe. When the humidity exceeds the set value, the control valve opens and the fresh air input device starts. The airflow connects with the channel of the regenerator 2 to discharge the moisture and then exchanges heat with the fresh air to recover heat. It is then transported to the heater 3 and then transported to the air supply pipe into the box 1 through the circulating fan 4. When the humidity is lower than the set value, the control valve is closed and the airflow flows directly through the heater 3 to re-enter the circulation.

[0052] Multiple sampling points are set inside the chamber to collect parameters such as heating temperature, humidity and heating time of tea leaves, with temperature fluctuation controlled within ±1℃.

[0053] The temperature control method of this dual-heat-source tea roasting and aroma-enhancing device specifically includes: depending on the type of tea, when the heating rate reaches 0.8℃ / min, the electric heater 3 stops operating, and only the far-infrared heater 5 operates. When the temperature reaches the set temperature T1, both heaters stop operating. When the temperature drops below the set temperature by 1℃, the electric heater 3 is activated to supplement the heat. When the humidity of the airflow exceeds the set value (specific value) or the temperature drops below the set temperature by more than 1℃, the electric heater 3 and the far-infrared heater 5 operate simultaneously. During the heating and dehumidification processes, both heat sources operate simultaneously; during the temperature maintenance process, the heaters either do not operate or only one heater operates.

[0054] Using graphene blocking plates to select the frequency and wavelength of far-infrared light transmission: By blocking frequency bands of light that are detrimental to the aroma enhancement of tea, the aroma enhancement effect of far-infrared heating on tea can be optimized. Within the frequency and wavelength range of far-infrared heating, some wavelengths are unfavorable to the aroma conversion of tea. Therefore, selecting suitable materials to block these unfavorable wavelengths is a feasible solution. Infrared light between 10μm and 15μm is preferred for heating tea. After graphene blocking, because graphene can intercept some frequency bands of far-infrared light, it is more beneficial for controlling the color and enhancing the aroma of tea. The roasted tea has a bright color, rich aroma, tea polyphenol retention rate >87%, and amino acid loss <10%.

[0055] Example 3

[0056] See Figures 1 to 3 The dual-heat-source tea roasting and aroma-enhancing device in Example 3 is similar to that in Example 1, except that a food-grade polyimide material is used to make the far-infrared shield instead of the graphene shield 6 in Example 1. The food-grade polyimide can be commercially available DuPont Kapton® FN or similar certified products, conforming to FDA 21 CFR 177.2450 (permitted for use in food contact materials), capable of withstanding temperatures above 200°C, and does not release harmful substances. It is also oil-resistant, water-resistant, and anti-aging. Polyimide has a 50-80% transmittance for far-infrared rays in the 10-15μm range and can be used to form flexible heating elements, making it more versatile.

[0057] In this embodiment, a food-grade polyimide shielding plate 6 is used to select the frequency and wavelength of far-infrared light transmission. By blocking light frequencies that are detrimental to the aroma and flavor enhancement of tea, the food-grade polyimide shielding plate 6 selectively transmits infrared light in the wavelength range of 10μm to 15μm to heat the tea, thereby optimizing the aroma and flavor enhancement effect of far-infrared heating. After shielding with food-grade polyimide, because the food-grade polyimide can block some frequency bands of far-infrared light, it is more beneficial to the color control and aroma enhancement of tea. The roasted tea has a bright color, rich aroma, tea polyphenol retention rate >87%, and amino acid loss <10%.

[0058] Example 4

[0059] See Figure 1 and Figure 3-4The dual-heat-source tea roasting and aroma-enhancing device in Example 4 is similar to that in Example 2, except that the far-infrared heater 5 or cavity of the tea roasting and aroma-enhancing device is made of food-grade alumina ceramic. Food-grade alumina ceramic, such as high-purity alumina ceramic (99.5% Al2O3), meets FDA and LFGB (German food-grade standards) certifications, does not release heavy metals (such as lead and cadmium), is heat-resistant (>1600℃), and is stable over long-term use. From a cost perspective, food-grade alumina ceramic is relatively inexpensive, offering the best cost-performance ratio and is suitable for mainstream tea roasting devices.

[0060] In this embodiment, a far-infrared heater or cavity for the tea roasting and aroma-enhancing device is made using food-grade alumina ceramic. The food-grade alumina ceramic blocks the light frequency bands that are not conducive to enhancing the aroma of tea, and selectively transmits infrared rays between 10μm and 15μm to heat the tea leaves, thus optimizing the far-infrared heating effect on enhancing the aroma of tea leaves. The roasted tea leaves have a bright color, rich aroma, tea polyphenol retention rate >85%, and amino acid loss <10%.

[0061] Comparative Example

[0062] Figure 5 A comparative dual-heat-source tea roasting and aroma-enhancing device is demonstrated. This device includes a housing 1, the top of which is equipped with a fresh air input device, a regenerator 2, an electric heater 3, a circulating fan 4, and an airflow guiding control valve. A far-infrared heater 5 and its corresponding quartz baffle 9 are installed on each of the left and right inner walls inside the housing 1. The far-infrared heaters 5 are blocked by the quartz baffles 9.

[0063] The housing 1 also has a multi-layer support structure 7 inside, which is a hollow support tube. The support tube is a hollow pipe that is connected or coiled on the same plane. The support tube is circular or rectangular and is used to place the tea tray. An air inlet pipe is connected between the support tube and the circulating fan, and an air outlet pipe is connected between the support tube and the fluid guide control valve. Multiple ventilation holes are evenly opened on the outer periphery of the support tube. The circulating fan delivers hot air heated by the electric heater to the support tube through the air inlet pipe. The hot air heats the tea in the tray placed on the support tube through the ventilation holes on the outer periphery of the support tube. Then the airflow flows through the air outlet pipe through the humidity monitor, control valve, and fresh air input device or regenerator.

[0064] The pipes connecting the fresh air input device, airflow guiding control valve, regenerator 2, heater 3, circulating fan 4, and support pipe are all hollow pipes. A touchscreen controller 8 is installed on the door panel of the enclosure 1. The touchscreen controller 8 is used to set and adjust parameters, and digitally displays the real-time temperature and humidity status and records process curves. The parameters include the heating temperature, humidity, and heating time inside the enclosure 1. Multiple temperature and humidity acquisition devices are also installed inside the enclosure 1.

[0065] The specific operation method of the dual-heat-source tea roasting and aroma-enhancing device includes: after starting the dual-heat-source tea roasting and aroma-enhancing device, the circulating fan 4 starts, and the electric heater 3 and the far-infrared heater 5 are simultaneously turned on for heating. The hot air generated by the electric heater 3 is transported to the support pipe inside the box 1 through the circulating fan 4. The airflow heats the tea tray through multiple evenly distributed vents 701 on the support pipe. The circulated gas is sequentially transported to the humidity monitor and airflow guidance control valve outside the box 1 through the exhaust pipe. When the humidity exceeds the set value, the control valve opens and the fresh air input device starts. The airflow connects with the channel of the regenerator 2 to discharge the moisture and then exchanges heat with the fresh air to recover heat. It is then transported to the heater 3 and then transported to the air supply pipe into the box 1 through the circulating fan 4. When the humidity is lower than the set value, the control valve is closed and the airflow flows directly through the electric heater 3 to re-enter the circulation.

[0066] Multiple collection points are set inside the chamber 1 to collect parameters such as heating temperature, humidity and heating time of tea leaves, with temperature fluctuation controlled within ±1℃.

[0067] The temperature control method of this dual-heat-source tea roasting and aroma-enhancing device specifically includes: depending on the type of tea, when the heating rate reaches 0.8℃ / min, the electric heater 3 stops operating, and only the far-infrared heater 5 operates. When the temperature reaches the set temperature T1, both heaters stop operating. When the temperature drops below the set temperature by 1℃, the electric heater 3 is activated to supplement the heat. When the humidity of the airflow exceeds the set value (specific value) or the temperature drops below the set temperature by more than 1℃, the electric heater 3 and the far-infrared heater 5 operate simultaneously. During the heating and dehumidification processes, both heat sources operate simultaneously; during the temperature maintenance process, the heaters either do not operate or only one heater operates.

[0068] The far-infrared heating using quartz baffle 9 will change some of the beneficial components of tea. Some of the far-infrared light is absorbed by the pigments and proteins on the surface of the tea, causing the surface of the tea to overheat and char. The roasted tea will have a dark or black color and will lose more than 30% of its aroma.

[0069] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tea roasting and aroma-enhancing device with dual heat sources, characterized in that, The tea roasting and aroma enhancement device includes a box (1). The top of the box (1) is equipped with a fresh air input device, a regenerator (2), an electric heater (3), a circulating fan (4), and an airflow guiding control valve. A far-infrared heater (5) and its corresponding graphene baffle (6) are installed on the inner walls of the left and right sides of the box (1).

2. The dual-heat-source tea roasting and aroma-enhancing device according to claim 1, characterized in that, The box (1) is also provided with a multi-layer support structure (7), which is a hollow support tube. The support tube is a hollow pipe that is connected or coiled on the same plane. The support tube is disc-shaped and is used to place the tea tray. An air inlet pipe is connected between the support tube and the circulating fan (4), and an air outlet pipe is connected between the support tube and the airflow guide control valve. Multiple ventilation holes (701) are evenly opened on the outer periphery of the support tube. The circulating fan (4) delivers the hot air heated by the electric heater (3) to the support tube through the air inlet pipe. The hot air heats the tea in the tray placed on the support tube through the ventilation holes (701) on the outer periphery of the support tube.

3. The dual-heat-source tea roasting and aroma-enhancing device according to claim 2, characterized in that, The support pipe is rectangular; the hot air delivered by the circulating fan (4) does not need to be heated by the electric heater (3) and is directly delivered to the support pipe through the air inlet pipe.

4. The tea roasting and aroma-enhancing device with dual heat sources according to claim 1, characterized in that, The wavelength range of the far-infrared light output by the far-infrared heater (5) after being blocked by the graphene baffle (6) is 10μm to 15μm.

5. The tea roasting and aroma-enhancing device with dual heat sources according to claim 1, characterized in that, The graphene baffle (6) is replaced with a food-grade modified polyimide film.

6. The tea roasting and aroma-enhancing device with dual heat sources according to claim 1, characterized in that, The far-infrared heater (5) and / or the cavity of the dual-heat-source tea roasting and aroma-enhancing device are made of food-grade alumina ceramic, and the food-grade alumina ceramic is high-purity alumina ceramic with a purity of not less than 99.5%.

7. The tea roasting and aroma-enhancing device with dual heat sources according to claim 1, characterized in that, The enclosure (1) is equipped with a temperature and humidity control system.

8. The tea roasting and aroma-enhancing device with dual heat sources according to claim 7, characterized in that, The temperature and humidity control system includes a temperature and humidity monitor installed on the top, side or front of the enclosure (1).

9. The tea roasting and aroma-enhancing device with dual heat sources according to claim 7, characterized in that, The temperature and humidity control system also includes a touch screen controller (8) installed on the side or upper part of the door panel of the enclosure (1). The touch screen controller (8) is used to set and adjust parameters, and to directly display real-time temperature and humidity data and record process curves.

10. The dual-heat-source tea roasting and aroma-enhancing device according to claim 7, characterized in that, The temperature and humidity control system also includes multiple temperature and humidity acquisition devices installed inside the housing (1).

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