Double-heat-source tea leaf baking and aroma improving device

Abstract

The invention discloses a device for performing baking and aroma enhancement on tea leaves by combining baking and aroma enhancement with far infrared aroma enhancement and an operation method thereof.The device for performing baking and aroma enhancement on the tea leaves comprises a box body, and a fresh air input device, a heat regenerator, an electric heater, a circulating fan, a temperature and humidity monitoring instrument and an airflow control valve are arranged at the top of the box body; the inner walls of the left side and the right side in the box body are each provided with a far infrared heater and a graphene baffle corresponding to the far infrared heater. The baffles made of graphene materials are selected to block far infrared light and only allow far infrared waves in part of frequency bands to penetrate through to heat tea leaves, meanwhile, circulating air and uniform air supply of a plurality of air outlets are combined, the temperature control precision of tea leaf baking aroma enhancement is improved, aroma enhancement of the tea leaves is facilitated, and the tea leaf baking aroma enhancement efficiency is improved. By comprehensively utilizing the advantages of hot air heating and far infrared heating fragrance extraction, the tea leaves are rich in fragrance and rich in layer.

Description

Technical Field

[0001] The invention belongs to the technical field of tea processing, and particularly relates to a dual-heat-source tea baking and aroma-enhancing device and an operating method thereof. Background Art

[0002] The primary processing of black tea primarily involves withering, rolling, fermentation, and drying, while the refining process primarily involves aroma enhancement, air separation, and blending. Withering is generally the foundation of black tea's aroma, rolling and fermentation are key to aroma formation, and drying and aroma enhancement are crucial processes for aroma quality. Drying is the final step in the primary processing of black tea. High temperatures rapidly inactivate enzymes, halting enzymatic reactions, preserving the tea's quality characteristics, and reducing moisture content for easier storage. Currently, research on withering, fermentation, and drying is primarily focused on the various steps in black tea processing. Three main methods are commonly used to enhance tea's aroma: baking, frying, and far-infrared heating. Baking is the most widely used. Baking typically involves heat transfer through convection, such as using a hot air oven to bake tea leaves. In addition to the method of aroma enhancement, factors influencing the aroma enhancement process include temperature, time, the tea's initial moisture content, and the rate of temperature rise.

[0003] During the roasting process, tea loses moisture and undergoes complex thermochemical reactions, such as the Maillard reaction and caramelization. These reactions alter the tea's compositional structure and even form new substances, thereby enhancing its aroma and further improving its quality. During tea processing, the leaf temperature is kept below 130°C, so the Maillard reaction is dominant. Tea leaves contain a large number of free amino acids and sugars, which are important flavor enhancers and precursors of Maillard products such as pyrazine and furfural derivatives. Increasing the temperature during roasting to enhance aroma facilitates the Maillard reaction, enhancing the tea's aroma and producing notes such as roasted, sweet, and caramel. However, excessive roasting can produce a burnt odor. Therefore, the temperature, humidity, and duration of tea roasting play a crucial role in tea quality.

[0004] While roasting is widely used for aroma enhancement, research on how optimizing roasting parameters affects the aroma quality of black tea is relatively scarce. Current roasters for aroma enhancement and re-roasting mostly use a single air delivery pipe, resulting in uneven airflow within the roaster, leading to inconsistent surface temperature and humidity of the tea leaves, and consequently, poor quality after roasting. Temperature control using a single heat source is inherently hysteretic. Whether using electric heaters or far-infrared heating, the hysteresis in heat transfer leads to a delay in temperature control. This often leads to premature control to prevent overheating, which can result in localized under-temperature conditions and lower 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, research on suitable far-infrared heating wavelengths and frequency bands for tea aroma enhancement is urgently needed. Using only temperature as a single factor for control results in unstable and inaccurate temperature control within the roasting chamber, hindering the enrichment of the tea's aroma. Current tea roasting practices also fail to consider energy efficiency: heat is often directly discharged into the environment, resulting in a waste of resources.

[0005] Based on the above background, it is necessary to further study the specific effects of baking and aroma-enhancing process parameters on the baking quality of tea, and to design operating devices and methods that can implement the determined baking and aroma-enhancing process parameters in the actual tea baking process. Summary of the Invention

[0006] To solve the above technical problems, the applicant has provided a technical solution that combines baking and far-infrared aroma enhancement, using a graphene material baffle to block far-infrared light and only allow far-infrared waves of a certain frequency band to pass through to heat the tea leaves. Furthermore, a technical solution combining circulating air and uniform air supply from multiple air outlets is adopted. The specific solution is as follows:

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

[0008] The box body is also provided with a multi-layer support structure, which is a hollow support tube. The support tube is a hollow pipe that is located on the same plane by being connected or coiled. The support tube can be disc-shaped or rectangular as needed, and is used to place a tea tray; an air inlet duct is connected between the support tube and the circulating fan, and an air outlet duct is connected between the support tube and the fluid control valve; a plurality of ventilation holes are evenly opened on the outer periphery of the support tube; the circulating fan transports the hot air heated / unheated by the electric heater to the support tube through the air inlet duct, and the hot air heats the tea leaves placed in the tray on the support tube through the ventilation holes on the outer periphery of the support tube, and the air flow flows through the temperature and humidity monitor, the airflow guide control valve and / or passes / does not pass through the fresh air input device and the regenerator through the air outlet duct.

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

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

[0011] A touchscreen controller is mounted on the side or top of the door panel of the box. This controller is used to set and adjust parameters, display real-time temperature and humidity data, and record process curves. These parameters include the heating temperature, humidity, and heating time within the box. The box is also equipped with multiple temperature and humidity acquisition devices. Temperature and humidity monitors are installed on the top, front, or side surfaces of the box to facilitate observation of the operating temperature within the box. The controller is electrically connected to the temperature and humidity acquisition devices and the temperature and humidity monitors, collectively forming the temperature and humidity control system of the dual-heat-source tea roasting and aroma enhancement device.

[0012] The operating method of the dual-heat source tea baking and aroma-enhancing device specifically includes: after starting the dual-heat source tea baking and aroma-enhancing device, the circulating fan is started, and the electric heater and the far-infrared heater are turned on for heating at the same time. The hot air generated by the electric heater is transported to the support tube in the box through the circulating fan, and the air flow heats the tea tray through multiple ventilation holes evenly distributed on the support tube. The circulated gas is transported to the temperature and humidity monitor and the air flow control valve outside the box in sequence through the air outlet pipe. When the humidity exceeds the set value, the control valve is opened and the fresh air input device is started. The air flow is connected to the regenerator channel to discharge moisture and then exchange heat with the fresh air, and then is transported to the heater, and then the air flow is transported to the air supply pipe and enters the box through the circulating fan; when the humidity is lower than the set value, the control valve is closed, and the air flow directly flows through the heater and enters the circulation again.

[0013] A plurality of collection points are arranged inside the box for collecting parameters such as the heating temperature, humidity and heating time of the tea leaves, and the temperature fluctuation is controlled within ±1°C.

[0014] The temperature control method of the dual-heat source tea baking and aroma device specifically includes: depending on the different tea leaves, when the heating rate reaches the set value, the value range is 0.5℃ / min-0.8℃ / min, the electric heater stops working and only the far-infrared heater works. Depending on the type of tea, when the temperature reaches the set temperature T1, both heaters stop working. When the temperature of the air flow inside the box is lower than the set temperature by more than 1℃, the electric heating and far-infrared work simultaneously. The two heat sources work simultaneously during the heating and dehumidification process, and the heater does not work or only one heater works during the temperature maintenance process.

[0015] This application adopts 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 the aroma of tea, making the aroma of tea rich in layers.

[0016] Hot air circulation heating primarily heats the surface of an object. There's a temperature difference between the inside and outside of an object. When the surface reaches the set temperature, some parts of the interior actually haven't. This can affect the thermal conversion of the tea's internal aromatic substances, hindering the tea's aroma and flavor enhancement. Generally, to achieve aroma enhancement, the heating temperature can be increased, but excessively high temperatures will affect the conversion of the tea's surface. Therefore, low-temperature, slow roasting is the only option, using lower temperatures and extended heating times. This is consistent with the low-temperature, slow roasting of tobacco and is also the current trend in tea roasting for aroma enhancement. However, for tea, precise temperature control has a significant impact on its quality. The magnitude and rate of temperature increase both significantly impact product quality, and roasting for too long can significantly reduce tea quality.

[0017] Based on this, the applicant proposed that during initial heating, electric heating and far-infrared heating be activated simultaneously, allowing the surface and interior of the tea leaves to reach the set temperature simultaneously. Only hot air circulation is then used, entering low-temperature heating mode. When the temperature slightly drops below the set temperature, weak heat supplementation is applied, and one of the heaters is activated. This method not only efficiently heats the tea leaves from the inside out, reducing the temperature difference from the inside out, but also allows for hot air circulation to replenish energy, achieving both aroma enhancement and energy conservation, contributing to stable tea quality.

[0018] Utilizing a graphene baffle to select the frequency and wavelength of far-infrared light transmission: Graphene is used to block frequency bands that are not conducive to tea aroma enhancement to optimize the aroma enhancement effect of far-infrared heating on tea. Within the frequency and wavelength range of far-infrared heating, some frequency wavelengths are not conducive to the conversion of tea aroma. Therefore, selecting suitable materials to block frequency bands that are not conducive to far-infrared heating is a feasible solution. Experiments have confirmed that after the graphene baffle blocks far-infrared light in the wavelength range of 10μm to 15μm, it can stimulate the aroma of tea without affecting the color and has a superior aroma enhancement effect. Specifically, after being blocked by graphene, because graphene can intercept far-infrared light in certain frequency bands, it is more beneficial to the color control and aroma enhancement of tea, resulting in a bright color and rich aroma. However, far-infrared heating blocked by a quartz baffle will change certain beneficial components of tea, causing the tea to darken and become black in color, and with a serious loss of aroma.

[0019] In some examples, the baffle can also be made of other materials that can transmit far-infrared rays in the wavelength range of 10μm to 15μm. In the baking scenario of tea and other ingredients, food safety is the primary consideration, so it is necessary to ensure that the selected materials are non-toxic and harmless, do not release harmful substances, and meet food contact safety standards; they are resistant to high temperatures and stable, do not decompose or deteriorate at 130°C; and do not chemically react with the ingredients, such as not absorbing odors or catalyzing deterioration. Therefore, optionally, a food-grade modified polyimide (PI) film is used. Food-grade polyimide can be made from commercially available DuPont Or similar certified products, in compliance with FDA 21CFR 177.2450 (allowed for food contact materials), can withstand high temperatures above 200°C, does not release harmful substances, and is oil-resistant, water-resistant, and aging-resistant.

[0020] In some examples, food-grade alumina ceramics are used to create the far-infrared heaters or chambers in tea roasting and aroma enhancement devices. Food-grade alumina ceramics, such as high-purity alumina ceramics (99.5% Al2O3), comply with FDA and LFGB (German food-grade standards), release no heavy metals (such as lead and cadmium), are heat-resistant (>1600°C), and offer long-term stability. From a cost perspective, food-grade alumina ceramics offer the lowest cost and best value, making them suitable for mainstream tea roasting devices.

[0021] Circulating air is delivered into the tea tray support duct, heating the tea leaves and removing water vapor from the tea leaves. If the moisture content exceeds a set value, it is connected to the regenerator channel to remove moisture. Simultaneously, fresh air enters, exchanging heat with the exhaust hot air to recover heat before entering the heater and being delivered to the oven via the circulating fan. When the moisture content of the circulating air falls below a set value, the fresh air flow stops, and a switching valve redirects the air into the heater, entering circulation mode. Direct exhaust and intake air have significant differences in temperature and humidity between the tea leaves, leading to undesirable conversions. However, with regenerating air, the fresh air entering the oven increases its temperature while also reducing its relative humidity, minimizing the temperature and humidity difference between the air flow and the tea leaves, achieving gentle heating. This enhances the tea's aroma and flavor, improving its quality. After dehumidification, fresh air enters. To minimize the temperature and humidity difference between the fresh air and the tea leaves, both electric heating and far-infrared heating are used to maintain a stable temperature rise rate or control temperature fluctuations to within ±1°C. The temperature rise rate and time required to reach a certain temperature are set for each tea variety and the specific tea roasting process.

[0022] The single-hole air supply mode of the air supply channel is changed to a multi-air outlet air supply mode with multiple ventilation holes on the periphery of the ventilation duct of the support device to achieve the purpose of uniform air supply heating, realize uniform heating of tea leaves during baking, and improve the aroma quality of tea leaves. By delivering circulating air to the multi-point air supply ports under the tray, it is ensured that the temperature of each layer is uniform and the tea leaves on each layer of the support frame are heated evenly. From the perspective of fluid mechanics, the multi-point uniform air supply of the fluid is much more uniform than the single-tube single-hole air supply. The fluid flow satisfies the Bernoulli equation. During the heating process, the uniformity of flow is achieved by optimizing the flow structure and the air supply points. It can also be optimized through CFD simulation of fluid dynamics software. Therefore, the use of multi-hole annular air ducts or multi-hole rectangular air ducts from under the tea tray is conducive to the uniformity of fluid flow.

[0023] Using a touch screen controller or a simple digital display controller, you can easily set and adjust parameters such as temperature, humidity, and heating time at the collection point. The digital display directly displays the real-time status of the parameters and records the process curve. The process parameters collected at the collection point can be selected according to actual needs. Multiple temperature and humidity collection points can be set, one collection point each at the top and bottom, or three collection points can be set at the top, middle, and bottom.

[0024] This application adopts dual heat source combination control to improve the temperature control accuracy of tea baking and aroma enhancement, which is beneficial to the enhancement of tea flavor. The comprehensive use of the advantages of hot air heating and far-infrared heating also makes the tea aroma rich and layered. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the main structure of the dual-heat source tea roasting and aroma-enhancing machine in accordance with an embodiment;

[0026] Figure 2 This is a schematic diagram of the circular support tube and air outlet layout;

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

[0028] Figure 4 Schematic diagram of the rectangular structure and air outlet of the support tube;

[0029] Figure 5 This is a schematic diagram of the main structure of a dual-heat source tea roasting and aroma-enhancing machine for comparative example;

[0030] In the figure, 1-box, 2-regenerator, 3-electric heater, 4-circulation fan, 5-far-infrared heater, 6-graphene shielding plate, 7-support structure, 701-ventilation hole, 8-touch screen controller, 9-quartz shielding plate. DETAILED DESCRIPTION

[0031] The invention will now be further described with reference to the accompanying drawings and specific embodiments. To simplify the drawings, only the parts related to the disclosure are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, to simplify the drawings and facilitate understanding, in some figures, only one of the components with the same structure or function is schematically shown, or only one of them is marked. In this article, "one" not only means "only one", but also "more than one", and "several" includes "two" and "more than two".

[0032] It should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on the specific circumstances.

[0033] In the present disclosure, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] In the description of this embodiment, the terms "up", "down", "left", "right", etc., and the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present disclosure.

[0035] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0036] Example 1

[0037] The following Figures 1 to 3 The present invention demonstrates a tea roasting and aroma-enhancing device with dual heat sources.

[0038] See also Figure 1 , Figure 1 This is a dual-heat-source tea baking and aroma-enhancing device of the present application. The tea baking and aroma-enhancing device comprises a box 1, the top of which is provided with a fresh air input device (not shown in the figure), a heat regenerator 2, an electric heater 3, a circulating fan 4 and an airflow guide control valve (not shown in the figure). A far-infrared heater 5 and its corresponding graphene baffle 6 are respectively installed on the left and right inner walls of the box 1. A multi-layer support structure 7 is also provided inside the box 1. 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.

[0039] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of the multi-layer support structure 7 in the dual-heat-source tea roasting and aroma-enhancing device of the present application. This support structure is a hollow support tube, a disc-shaped hollow pipe that is connected or coiled in the same plane and is used to hold the tea tray. An air inlet duct is connected between the support tube and the circulating fan 4, and an air outlet duct is connected between the support tube and the gas guide control valve. Multiple ventilation holes 701 are evenly distributed around the outer circumference of the support tube.

[0040] See also 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 the present application. A circulating fan 4 delivers hot air heated by the electric heater 3 to the support tube via an air inlet duct. The hot air passes through ventilation holes 701 on the outer periphery of the support tube, heating the tea leaves placed in a tray on the support tube. The air then flows through the air outlet duct, passing through the humidity monitor, the airflow control valve, and the fresh air input device or regenerator 2. The pipes connecting the fresh air input device, airflow control valve, regenerator 2, heater 3, circulating fan 4, and support tube are all hollow pipes.

[0041] A touch screen controller 8 is installed on the door panel of the box 1. The touch screen controller 8 is used to set and adjust parameters, and digitally display the real-time status of temperature and humidity and record process curves. The parameters include the heating temperature, humidity and heating time inside the box 1. The box 1 is also provided with a plurality of temperature and humidity acquisition devices 9, which are respectively arranged in the upper part, middle part and lower part of the box 1. A temperature and humidity monitor is provided on the top, front or side elevation of the box 1 to facilitate staff to observe the working temperature inside the box. The controller 8 is electrically connected to the temperature and humidity acquisition device 9 and the temperature and humidity monitor, and together constitute the temperature and humidity control system of the dual-heat source tea baking and aroma device.

[0042] In this embodiment, the operating method of the dual-heat source tea baking and aroma enhancement device specifically includes: after starting the dual-heat source tea baking and aroma enhancement device, the circulating fan 4 is started, and the electric heater 3 and the far-infrared heater 5 are turned on for heating at the same time. The hot air generated by the electric heater 3 is transported to the support tube in the box 1 through the circulating fan 4, and the air flow heats the tea tray through multiple vents 701 evenly distributed on the support tube. The circulated gas is transported to the temperature and humidity monitor and the airflow guide control valve outside the box 1 in turn through the air outlet 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 regenerator 2 channel to discharge moisture and then exchange heat with the fresh air to recover heat, and then is transported to the heater 3, and then the airflow is transported to the air supply pipe through the circulating fan 4 to enter the box 1; when the humidity is lower than the set value, the control valve is closed, and the airflow flows directly through the heater 3 and enters the circulation again.

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

[0044] The temperature control method of the dual-heat source tea baking and aroma device specifically includes: according to different tea leaves, when the heating rate reaches 0.5°C / min, the electric heater 3 stops working and only the far-infrared heater 5 works. When the temperature reaches the set temperature T1, both heaters stop working. When the temperature is 1°C lower than the set temperature, the electric heater 3 is started to supplement heat. When the humidity of the airflow exceeds the set value (specific value) or the temperature is more than 1°C lower than the set temperature, the electric heater 3 and the far-infrared heater 5 work simultaneously. The two heat sources work simultaneously during the heating and dehumidification process, and the heaters do not work or only one heater works during the temperature maintenance process.

[0045] The frequency and wavelength of far-infrared light transmission are selected by using the graphene baffle 6: the graphene baffle 6 is used to block the frequency band light that is not conducive to the aroma enhancement of tea to optimize the aroma enhancement effect of far-infrared heating on tea. In the frequency wavelength range of far-infrared heating, some frequency wavelengths are not conducive to the conversion of tea aroma. Therefore, it is a feasible solution to select suitable materials to block the frequency wavelengths that are not conducive to the frequency wavelength of far-infrared heating. Preferably, infrared rays between 10μm and 15μm are used to heat the tea. After being blocked by graphene, since graphene can intercept far-infrared light of some frequency bands, it is more beneficial to the color control and aroma enhancement of tea. The baked tea has a bright color, rich aroma, tea polyphenol retention rate>88%, and amino acid loss<10%.

[0046] Example 2

[0047] The following Figure 1 and Figure 3-4 The present invention demonstrates a tea roasting and aroma-enhancing device with dual heat sources.

[0048] See also Figure 1 and Figure 4 , Figure 1 This is a tea baking and aroma-enhancing device with dual heat sources. Figure 4 yes Figure 1 The multi-layer support structure 7 inside the housing 1 of the dual-heat source tea roasting and aroma-enhancing device 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 a tea tray; an air inlet duct is connected between the support tube and the circulating fan 4, and an air outlet duct is connected between the support tube and the fluid guide control valve; a plurality of ventilation holes 701 are evenly opened on the periphery of the support tube.

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

[0050] A touch screen controller is installed on the door panel of the box body 1. The touch screen controller is used to set and adjust parameters, and digitally display the real-time status of temperature and humidity and record process curves. The parameters include the heating temperature, humidity and heating time inside the box body. The box body 1 is also provided with a plurality of temperature and humidity acquisition devices, which are respectively arranged in the upper and lower parts of the box body 1. A temperature and humidity monitor is provided on the top, front or side elevation of the box body 1 to facilitate staff to observe the working temperature inside the box body. The controller 8 is electrically connected to the temperature and humidity acquisition device 9 and the temperature and humidity monitor, and together constitute the temperature and humidity control system of the dual-heat source tea baking and aroma device.

[0051] The operating method of the dual-heat source tea baking and aroma-enhancing device specifically includes: after starting the dual-heat source tea baking and aroma-enhancing device, the circulating fan 4 is started, and the electric heater 3 and the far-infrared heater 5 are turned on for heating at the same time. The hot air generated by the electric heater 3 is transported to the support tube in the box 1 through the circulating fan 4, and the air flow heats the tea tray through multiple ventilation holes 701 evenly distributed on the support tube. The circulated gas is transported to the temperature and humidity monitor and the air flow guide control valve outside the box 1 in sequence through the air outlet pipe. When the humidity exceeds the set value, the control valve is opened and the fresh air input device is started. The air flow is connected to the regenerator 2 channel to discharge moisture and then exchange heat with the fresh air to recover heat, and then is transported to the heater 3, and then the air flow is transported to the air supply pipe and enters the box 1 through the circulating fan 4; when the humidity is lower than the set value, the control valve is closed, and the air flow directly flows through the heater 3 and enters the circulation again.

[0052] Multiple collection points are set inside the box to collect parameters such as tea heating temperature, humidity and heating time, and the temperature fluctuation is controlled within ±1℃.

[0053] The temperature control method of the dual-heat source tea baking and aroma device specifically includes: according to different tea leaves, when the heating rate reaches 0.8℃ / min, the electric heater 3 stops working and only the far-infrared heater 5 works. When the temperature reaches the set temperature T1, both heaters stop working. When the temperature is 1℃ lower than the set temperature, the electric heater 3 is started to supplement heat. When the humidity of the airflow exceeds the set value (specific value) or the temperature is more than 1℃ lower than the set temperature, the electric heater 3 and the far-infrared heater 5 work at the same time. The two heat sources work simultaneously during the heating and dehumidification process, and the heater does not work or only one heater works during the temperature maintenance process.

[0054] Graphene shielding is used to select the frequency and wavelength of far-infrared light transmission: Graphene shielding is used to block the frequency bands of light that are not conducive to the aroma and flavor of tea to optimize the aroma and flavor enhancement effect of far-infrared heating on tea. Within the frequency and wavelength range of far-infrared heating, some frequency wavelengths are not conducive to the conversion of tea aroma. Therefore, selecting suitable materials to block the frequency wavelengths that are not conducive to the far-infrared heating frequency wavelength is a feasible solution. Preferably, infrared rays between 10μm and 15μm are used to heat the tea leaves. After being shielded by graphene, since graphene can intercept far-infrared light of some frequency bands, it is more beneficial to the color control and aroma enhancement of the tea leaves. The baked tea leaves have a bright color, rich aroma, tea polyphenol retention rate> 87%, and amino acid loss<10%.

[0055] Example 3

[0056] See also Figures 1 to 3 The dual-heat source tea baking and aroma device of embodiment 3 is similar to embodiment 1, except that the far infrared shielding plate is made of food-grade polyimide material in embodiment 3, replacing the graphene shielding plate 6 in embodiment 1. Food-grade polyimide can be made of commercially available DuPont This product complies with FDA 21CFR 177.2450 (approved for food contact materials) and is heat-resistant over 200°C without releasing harmful substances. It is also oil-resistant, water-resistant, and aging-resistant. Polyimide has a 50-80% transmittance for far-infrared radiation in the 10-15μm range and can be used to form flexible heating sheets, offering a wider range of adaptability.

[0057] In this embodiment, a food-grade polyimide baffle 6 is used to select the frequency and wavelength of far-infrared light transmission: by blocking light in the frequency band that is detrimental to tea aroma and flavor enhancement, the food-grade polyimide baffle 6 selectively transmits infrared light in the wavelength range of 10μm to 15μm to heat the tea leaves, thereby optimizing the far-infrared heating effect on tea aroma and flavor enhancement. After being shielded by the food-grade polyimide, since the food-grade polyimide can intercept a portion of the far-infrared light frequency band, it is more beneficial for controlling the color and enhancing the flavor of the tea leaves. The roasted tea leaves have a bright color and rich aroma, with a tea polyphenol retention rate of >87% and an amino acid loss of <10%.

[0058] Example 4

[0059] See also Figure 1 and Figure 3-4The dual-heat source tea roasting and aroma-enhancing device of Example 4 is similar to that of Example 2, except that in Example 4, food-grade alumina ceramics are used to make the far-infrared heater 5 or cavity of the tea roasting and aroma-enhancing device. Food-grade alumina ceramics, such as high-purity alumina ceramics (99.5% Al2O3), comply with FDA, LFGB (German food-grade standards), and other certifications. They do not release heavy metals (such as lead and cadmium), are resistant to high temperatures (>1600°C), and are stable in long-term use. From a cost perspective, food-grade alumina ceramics are relatively low in cost, have the best cost-effectiveness, and are suitable for mainstream tea roasting devices.

[0060] In this embodiment, food-grade alumina ceramics are used to make the far-infrared heater or cavity of the tea baking and aroma-enhancing device. The food-grade alumina ceramics block the frequency band light that is not conducive to the aroma and fragrance enhancement of tea, and selectively transmit infrared rays between 10 μm and 15 μm to heat the tea, thereby optimizing the aroma-enhancing effect of far-infrared heating on the tea. After baking, the tea leaves have a bright color and rich aroma, the tea polyphenol retention rate is greater than 85%, and the amino acid loss is less than 10%.

[0061] Comparative Example

[0062] Figure 5 A comparative example of a dual-heat-source tea roasting and aroma-enhancing device is presented. This device comprises 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 control valve. A far-infrared heater 5 and its corresponding quartz baffle 9 are mounted on each of the left and right inner walls of the housing 1. The far-infrared heater 5 is shielded by the quartz baffle 9.

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

[0064] The pipes connecting the fresh air input device, airflow control valve, regenerator 2, heater 3, circulating fan 4, and support tube are all hollow. A touchscreen controller 8 is mounted on the door panel of the cabinet 1. This controller is used to set and adjust parameters, digitally display the real-time temperature and humidity, and record process curves. These parameters include the heating temperature, humidity, and heating time within the cabinet 1. Multiple temperature and humidity acquisition devices are also located within the cabinet 1.

[0065] The operating method of the dual-heat source tea baking and aroma-enhancing device specifically includes: after starting the dual-heat source tea baking and aroma-enhancing device, the circulating fan 4 is started, and the electric heater 3 and the far-infrared heater 5 are turned on for heating at the same time. The hot air generated by the electric heater 3 is transported to the support tube in the box 1 through the circulating fan 4, and the air flow heats the tea tray through multiple vents 701 evenly distributed on the support tube. The circulated gas is transported to the humidity monitor and the air flow guide control valve outside the box 1 in sequence through the air outlet pipe. When the humidity exceeds the set value, the control valve is opened and the fresh air input device is started. The air flow is connected to the regenerator 2 channel to discharge moisture and then exchange heat with the fresh air to recover heat, and then is transported to the heater 3, and then the air flow is transported to the air supply pipe by the circulating fan 4 to enter the box 1; when the humidity is lower than the set value, the control valve is closed, and the air flow directly flows through the electric heater 3 and enters the circulation again.

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

[0067] The temperature control method of the dual-heat source tea baking and aroma device specifically includes: according to different tea leaves, when the heating rate reaches 0.8℃ / min, the electric heater 3 stops working and only the far-infrared heater 5 works. When the temperature reaches the set temperature T1, both heaters stop working. When the temperature is 1℃ lower than the set temperature, the electric heater 3 is started to supplement heat. When the humidity of the airflow exceeds the set value (specific value) or the temperature is more than 1℃ lower than the set temperature, the electric heater 3 and the far-infrared heater 5 work at the same time. The two heat sources work simultaneously during the heating and dehumidification process, and the heater does not work or only one heater works during the temperature maintenance process.

[0068] The far-infrared heating blocked by the quartz baffle 9 will change some beneficial components of the tea leaves. Part of the far-infrared light is absorbed by the pigments and proteins on the surface of the tea leaves, causing the surface of the tea leaves to overheat and burn. The color of the tea leaves after baking will be dark and black, and the aroma will be seriously lost by more than 30%.

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

Claims

1. A dual-heat source tea roasting and aroma-enhancing device, comprising a box (1), a fresh air input device, a heat regenerator (2), an electric heater (3), a circulating fan (4) and an air flow guide control valve are provided on the top of the box (1), and a far-infrared heater (5) and a corresponding graphene baffle (6) are respectively installed on the left and right inner walls of the box (1).

2. The dual-heat source tea baking and aroma device according to claim 1, wherein a multi-layer support structure (7) is further provided inside the box (1), and the support structure (7) is a hollow support tube, and the support tube is a hollow pipe that is connected or coiled in the same plane, and the support tube is disc-shaped or rectangular, and is used to place a tea tray; an air inlet duct is connected between the support tube and the circulating fan (4), and an air outlet duct is connected between the support tube and the air flow control valve; a plurality of ventilation holes (701) are evenly opened on the outer periphery of the support tube; the circulating fan (4) transports the hot air heated / unheated by the electric heater (5) to the support tube through the air inlet duct, and the hot air heats the tea leaves in the tray 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 1, wherein the wavelength range of the far-infrared light output by the far-infrared heater (5) after being blocked by the graphene baffle (6) is 10 μm to 15 μm.

4. The dual-heat-source tea roasting and aroma-enhancing device according to claim 1, wherein the graphene baffle (6) is replaced with a food-grade modified polyimide (PI) film.

5. The dual-heat source tea roasting and aroma-enhancing device according to claim 1, wherein 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 ceramics, and the food-grade alumina ceramics are high-purity alumina ceramics with a purity of not less than 99.5%.

6. The dual-heat-source tea roasting and aroma-enhancing device according to claim 1, wherein a temperature and humidity monitoring device is provided on the top, side or front of the box (1).

7. The dual-heat source tea roasting and aroma-enhancing device according to claim 1, wherein a touch screen controller (8) is installed on the side or upper part of the door panel of the box (1), and the touch screen controller (8) is used to set and adjust parameters, and directly display real-time data of temperature and humidity and record process curves. A plurality of temperature and humidity acquisition devices are also provided inside the box (1).

8. An operating method of the dual-heat-source tea roasting and aroma-enhancing device according to any one of claims 1 to 7, wherein after the dual-heat-source tea roasting and aroma-enhancing device is started, the circulating fan (4) is started, the electric heater (3) and the far-infrared heater (5) are simultaneously turned on for heating, and the temperature and humidity collecting device inside the box (1) is also started at the same time, the hot air generated by the electric heater (3) is transported to the support pipe in the box (1) through the circulating fan (4), the air flow heats the tea tray through a plurality of vents (701) evenly distributed on the support pipe, the circulated gas is sequentially transported to the temperature and humidity monitor and the air flow guide control valve outside the box (1) through the air outlet pipe, when the humidity exceeds a set value, the control valve is opened, the fresh air input device is started, the air flow is connected to the regenerator (2) channel to discharge moisture, and then exchanges heat with the fresh air to recover heat, and then is transported to the electric heater (3), and then the circulating fan (4) transports the air flow to the air supply pipe to enter the box (1); when the humidity is lower than the set value, the control valve is closed, and the air flow directly flows through the electric heater (3) and enters the circulation again.

9. The operating method of the dual-heat source tea roasting and aroma-enhancing device according to claim 8, wherein, depending on the different tea leaves, when the heating rate reaches a set value, the value range is 0.5°C / min-0.8°C / min, the electric heater (3) stops operating and only the far-infrared heater (5) works.

10. The operating method of the dual-heat source tea roasting and aroma-enhancing device according to claim 8, wherein when the temperature reaches the set temperature T1, the electric heater (3) and the far-infrared heater (5) both stop working; when the temperature is 1°C lower than the set temperature, the electric heater (3) is started to supplement heat; when the temperature of the air flow inside the box is more than 1°C lower than the set temperature, the electric heater (3) and the far-infrared heater (5) work simultaneously.

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