A coffee maker

Abstract

The utility model relates to a coffee machine, including brewing unit, this brewing unit has the brewing chamber for coffee powder extraction, still including the bubble water generating device for producing micro - nano bubble water, the water outlet of bubble water generating device with above -mentioned brewing chamber's brewing water inlet is in fluid intercommunication, under brewing state, micro - nano bubble water passes through brewing water inlet and flows into brewing chamber from top to bottom. Compared with prior art, the utility model uses micro - nano bubble water to improve extraction efficiency, thereby can quickly extract the positive flavoring material that is easy to dissolve in water, and ends extraction before the negative flavoring material is dissolved in water, and the mouthfeel of coffee is improved.

Description

Technical Field

[0001] This utility model relates to the field of household appliances, and in particular to a coffee machine. Background Technology

[0002] The coffee-making process of a coffee machine generally includes steps such as grinding beans, loading, tamping, brewing, grounds removal, and cleaning. The brewing unit is the key component for completing these steps. Examples include Chinese invention patents such as "Coffee Machine Brewing Mechanism" (application number CN202411457336.0, publication number CN119214480A) and "A Coffee Machine Brewing Device with Heating Function" (application number CN202411204282.7, publication number CN118844805A). Furthermore, existing brewing units generally include a brewing cup and a brewing stopper, with coffee extraction achieved through the interaction between the brewing cup and the brewing stopper.

[0003] Coffee extraction requires strict control of the extraction speed. Oils and positive flavor compounds in coffee are more easily extracted in the initial stages of extraction, but improper timing can lead to the extraction of astringency and other negative flavor compounds later in the extraction process. Current coffee machines generally use heated water for extraction, which is not only inefficient but also, by prolonging the extraction time, easily extracts negative flavor compounds, affecting the coffee's taste. Furthermore, the infiltration of ordinary water relies on passive diffusion, which, limited by the porosity of coffee grounds and the surface tension of water, can easily result in insufficient extraction of fat-soluble flavor compounds. Summary of the Invention

[0004] The first technical problem this invention aims to solve is to provide a coffee machine with high coffee extraction efficiency, in contrast to existing technologies.

[0005] The second technical problem to be solved by this utility model is to provide a coffee machine with high coffee extraction efficiency and good extraction effect, which is in contrast to the prior art.

[0006] The technical solution adopted by this utility model to solve at least one of the above-mentioned technical problems is as follows: a coffee machine, including a brewing unit, the brewing unit having a brewing chamber for extracting coffee powder, characterized in that it further includes a bubble water generating device for generating micro-nano bubble water, the water outlet of the bubble water generating device being fluidly connected to the brewing water inlet of the brewing chamber, and in the brewing state, micro-nano bubble water flows into the brewing chamber from top to bottom through the brewing water inlet.

[0007] Furthermore, the brewing chamber extends at an angle relative to the vertical direction. During brewing, micro-nano bubble water flows from top to bottom into the lower end of the brewing chamber through the brewing inlet. This helps to extend the rising path of the bubbles in the micro-nano bubble water within the coffee powder, allowing them to interact more fully with the coffee powder, thereby further improving the coffee extraction mass transfer coefficient, and ultimately enhancing the coffee extraction efficiency and effect.

[0008] Furthermore, the bubble water generator includes a gas tank and a vertically extending Venturi tube. The upper inlet of the Venturi tube is an upper water inlet for ordinary water to flow in, while the lower inlet is a lower water outlet for micro-nano bubble water to flow out. The lower water outlet is in fluid communication with the aforementioned brewing water inlet, and an air inlet in fluid communication with the air outlet of the gas tank is provided on the side wall of the Venturi tube. In this way, ordinary water and gas entering the Venturi tube utilize the Venturi effect to form micro-nano bubble water, and the formed micro-nano bubble water enters the brewing chamber through the brewing water inlet.

[0009] Furthermore, the venturi tube is provided with a flow channel extending along its length. This flow channel includes, from top to bottom, a guide section, a constriction section, a throat section, and a diffuser section, all four being sequentially connected vertically. The upper port of the guide section is connected to the upper inlet, while the lower port of the diffuser section is connected to the lower outlet. The radius of the guide section remains constant from top to bottom and is equal to the diameter of the upper port of the constriction section. The radius of the constriction section decreases from top to bottom, while the radius of the diffuser section increases from top to bottom. The radius of the throat section is equal to the diameter of the lower port of the constriction section and less than or equal to the diameter of the upper port of the diffuser section, and the radius of the throat section remains constant from top to bottom.

[0010] The Venturi tube is further provided with an air inlet chamber and a mixing chamber. The air inlet is located on the air inlet chamber and surrounds the contraction section and throat section. The lower end of the throat section communicates with the air inlet chamber. The mixing chamber surrounds the diffuser section, and the lower end of the diffuser section has circumferentially spaced guide ports that communicate with the mixing chamber. In this way, ordinary water flowing into the flow channel from the upper inlet creates a Venturi effect in the contraction section, throat section, and diffuser section. At the throat section, it draws in gas that has entered the air inlet chamber from the air inlet. The gas and water flow together into the diffuser section for primary mixing and then undergo secondary mixing in the mixing chamber. Finally, the micro-nano bubble water formed flows out of the Venturi tube through the lower outlet.

[0011] Furthermore, an upper tube and a lower tube are coaxially fitted into the inner cavity of the venturi tube from top to bottom. The upper tube is shaped like an inverted cone, hollow inside to form the aforementioned constriction section. The bottom of the upper tube extends downward along the axial direction from the lower end of the constriction section to form the aforementioned throat section. The lower tube is divided into upper and lower parts. The diameter of the upper part is larger than that of the lower part to accommodate the upper tube, and windows are spaced apart circumferentially on the wall of the upper part. The inner cavity of the lower part forms the aforementioned diffusion section, and concave notches are spaced apart circumferentially at the lower end of the lower tube to form the aforementioned guide ports.

[0012] Furthermore, a horizontally extending central wall is provided between the upper and lower parts, with a through hole in the center of the central wall along the axial direction. This through hole forms the upper port of the diffuser section. The upper surface of the central wall slopes circumferentially from the outside to the inside towards the through hole, and a gap is left between the lower end of the upper tube and the upper surface of the central wall. This design allows for the construction of a contraction section, a throat section, and a diffuser section within the Venturi tube to generate the Venturi effect. The opening of the window and the design of the central wall ensure that the lower port of the throat section communicates with the air intake chamber, guaranteeing smooth gas intake. The opening of the notch ensures that gas and water flow enter the mixing chamber and undergo secondary mixing.

[0013] Furthermore, the bubble water generating device also includes a water pump and a heater for heating water. The heating inlet of the heater is fluidly connected to the outlet of the water pump, while the heating outlet is fluidly connected to the upper inlet. In this way, water with a certain kinetic energy flows from the upper inlet into the flow channel of the venturi tube through the water pump and heater.

[0014] Furthermore, the brewing unit includes a brewing cup and a brewing plug positioned vertically opposite the brewing cup. The brewing cup is inclined relative to the vertical direction and has a push plate inside. The push plate is positioned along the cross-sectional direction of the brewing cup. In the brewing state, the push plate, the corresponding part of the side wall of the brewing cup, and the end of the brewing plug together form the brewing chamber, and the brewing inlet is located on the end face of the brewing plug. This creates a brewing chamber structure in the brewing state, allowing micro-nano bubble water to flow into the brewing chamber from top to bottom.

[0015] Furthermore, the brewing plug is equipped with a water inlet, the water inlet connector of which is connected to the lower water outlet via a water inlet pipe, while the water outlet connector is in fluid communication with the brewing water inlet. The water inlet facilitates fluid communication between the lower water outlet of the venturi tube and the brewing water inlet.

[0016] Furthermore, the water inlet component includes a bent-shaped water inlet block. The water inlet connector is located at one end of the water inlet block, and the water outlet connector is located at the other end. The water inlet block is inserted into the cavity inside the brewing plug along its length. The water inlet block has a water inlet channel along its length for connecting the water inlet connector and the water outlet connector. The portion of the water inlet channel containing the water outlet connector extends along the length of the brewing plug, and the water outlet connector is vertically aligned with the brewing water inlet. By providing a water inlet channel in the water inlet component, the water inlet connector and the water outlet connector can be connected, and the micro-nano bubble water can be better guided to the brewing water inlet. In other words, the water inlet component simultaneously serves the functions of water path connection and guidance.

[0017] Furthermore, the upper part of the water inlet block is provided with a first mounting block for fixing to a corresponding position on the brewing plug. This first mounting block extends along the length of the brewing plug. The lower part of the water inlet block is provided with a second mounting block for fixing to another corresponding position on the brewing plug. The extension direction of the second mounting block is perpendicular to the first mounting block. The first and second mounting blocks facilitate the installation of the water inlet component on the brewing plug and also ensure the secure installation of the water inlet component.

[0018] Furthermore, the brewing plug is hollow, forming the aforementioned cavity, and a connecting seat is protruding on its inner bottom surface for the water outlet connector of the water inlet to be inserted into. This connecting seat is cylindrical and extends along the length of the brewing plug, while the brewing water inlet extends along the axis of the connecting seat. A vertical gap is maintained between the water outlet connector and the brewing water inlet along the length of the brewing plug. This facilitates the insertion of the water inlet connector into the brewing plug and also ensures fluid communication between the water outlet connector and the brewing water inlet. Furthermore, the vertical gap between the water outlet connector and the brewing water inlet allows micro-nano bubble water to flow relatively smoothly into the brewing chamber.

[0019] Compared with existing technologies, the advantages of this invention are as follows: This invention is equipped with a sparkling water generator, which uses micro-nano sparkling water to extract coffee powder. Compared with ordinary water, micro-nano sparkling water has a huge specific surface area, which can significantly increase the contact interface between water and coffee powder, thereby improving extraction efficiency. Coffee extraction requires the extraction of positive flavor substances (e.g., caffeic acid, chlorogenic acid, etc.) in a short time. If the extraction time is prolonged, negative flavor substances (e.g., quinic acid, tannic acid, etc.) are easily extracted. Micro-nano sparkling water can significantly shorten the extraction process and improve extraction efficiency, thereby quickly extracting positive flavor substances that are easily soluble in water, and ending the extraction before negative flavor substances dissolve in water, thus improving the taste of coffee.

[0020] Furthermore, in the brewing state of this invention, micro-nano bubble water flows from top to bottom into the brewing chamber through the brewing inlet. This allows the micro-nano bubble water to flow into the coffee powder from top to bottom, thus fully wetting the coffee powder. When the micro-nano bubble water flows into the coffee powder, it utilizes the porous structure formed between the coffee powder particles (compacted coffee powder) to further shear the bubbles in the micro-nano bubble water, forming more micron-sized bubbles (most of the micro-nano bubble water entering from the brewing inlet consists of nano-sized bubbles). This is beneficial for improving the extraction effect of the coffee, thereby further enhancing the taste of the coffee. Moreover, the microscale turbulence generated during the bubble's ascent can effectively disrupt the concentration boundary layer on the surface of the coffee powder, increasing the extraction mass transfer coefficient by 3 to 5 times, further improving the coffee extraction efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the coffee machine in an embodiment of the present invention;

[0022] Figure 2 This is a cross-sectional view of the coffee machine in an embodiment of the present invention;

[0023] Figure 3 for Figure 2 Enlarged view of section A;

[0024] Figure 4 This is a schematic diagram of the structure of the bubble water generator in the embodiment of this utility model;

[0025] Figure 5 This is a cross-sectional view of the Venturi tube in an embodiment of this utility model;

[0026] Figure 6 This is an exploded view of the Venturi tube in the embodiment of this utility model;

[0027] Figure 7 This is a schematic diagram of the lower embedded tube in an embodiment of the present invention;

[0028] Figure 8 This is a schematic diagram of the water inlet component in an embodiment of this utility model. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Since the embodiments disclosed in this utility model can be arranged in different directions, these terms indicating direction are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0031] like Figures 1-8 As shown, a coffee machine includes a brewing unit 1 with a brewing chamber 10 for extracting coffee powder. Further, it includes a bubble water generator 3 for generating micro-nano bubble water. The outlet of the bubble water generator 3 is fluidly connected to the brewing inlet 101 of the brewing chamber 10. During brewing, the micro-nano bubble water flows from top to bottom into the brewing chamber 10 through the brewing inlet 101. It is evident that this invention includes a bubble water generator 3, which extracts coffee powder using micro-nano bubble water. Compared to ordinary water, micro-nano bubble water has a large specific surface area, significantly increasing the contact interface between water and coffee powder, thus improving extraction efficiency. Coffee extraction requires the extraction of positive flavor compounds (such as caffeic acid and chlorogenic acid) within a short time. If the extraction time is longer, negative flavor compounds (such as quinic acid and tannic acid) are easily extracted. Micro-nano bubble water can significantly shorten the extraction process and improve extraction efficiency, thereby quickly extracting positive flavor compounds that are easily soluble in water, and ending the extraction before negative flavor compounds dissolve in water, thus improving the taste of coffee.

[0032] Furthermore, in the brewing state of this invention, micro-nano bubble water flows from top to bottom into the brewing chamber 10 through the brewing inlet 101, thus fully wetting the coffee powder. When the micro-nano bubble water flows into the coffee powder, it utilizes the porous structure formed between the coffee powder particles (compacted coffee powder) to further shear the bubbles in the micro-nano bubble water, forming more micron-sized bubbles (most of the micro-nano bubble water entering from the brewing inlet 101 consists of nano-sized bubbles). This is beneficial for improving the extraction effect of the coffee, thereby further enhancing the taste. Moreover, the microscale turbulence generated during the bubble rise process effectively disrupts the concentration boundary layer on the surface of the coffee powder, increasing the extraction mass transfer coefficient by 3 to 5 times, further improving the coffee extraction efficiency.

[0033] like Figure 3 As shown, preferably, the brewing chamber 10 extends vertically at an angle relative to the vertical direction. During brewing, micro-nano bubble water flows from top to bottom into the lower end of the brewing chamber 10 through the brewing inlet 101. This extends the rising path of the bubbles in the micro-nano bubble water within the coffee powder, allowing them to interact more fully with the coffee powder, thereby further improving the coffee extraction mass transfer coefficient, and ultimately enhancing the coffee extraction efficiency and effect.

[0034] like Figure 1 and Figure 4 As shown, the aforementioned bubble water generating device 3 includes a gas tank 5 and a vertically extending Venturi tube 4. The upper inlet of the Venturi tube 4 is an upper water inlet 41 for ordinary water to flow in, while the lower inlet is a lower water outlet 42 for micro-nano bubble water to flow out. Furthermore, an air inlet 43 is provided on the side wall of the Venturi tube 4, which is fluidly connected to the air outlet of the gas tank 5, and the lower water outlet 42 is fluidly connected to the aforementioned brewing water inlet 101. Thus, ordinary water and gas entering the Venturi tube 4 utilize the Venturi effect to form micro-nano bubble water, which then enters the brewing chamber 10 through the brewing water inlet 101. Further, the aforementioned bubble water generating device 3 also includes a water pump 6, a gas valve 51, a water valve 61, and a heater 7 (specifically a boiler in this embodiment) for heating water. The heating water inlet of the heater 7 is fluidly connected to the water outlet of the water pump 6, while the heating water outlet is fluidly connected to the aforementioned upper water inlet 41. Thus, water with a certain kinetic energy flows from the upper inlet 41 into the flow channel 40 of the Venturi tube 4 via the water pump 6 and heater 7. The air outlet of the air tank 5 is connected to the air inlet 43 of the Venturi tube 4 through the air inlet pipe 52, and the air valve 51 is installed on the air inlet pipe 52 to control its opening and closing. The water inlet of the water pump 6 is in fluid communication with the water outlet of the water tank (not shown), and the water outlet is connected to the heating inlet of the heater 7 through the water outlet pipe 62, and the water outlet pipe 62 is equipped with a water valve 61 to control its opening and closing.

[0035] Specifically, such as Figure 5 As shown, the Venturi tube 4 has a flow channel 40 extending along its length. The flow channel 40 includes, from top to bottom, a guide section 401, a contraction section 402, a throat section 403, and a diffuser section 404, all connected sequentially. The upper port of the guide section 401 is connected to the upper inlet 41, while the lower port of the diffuser section 404 is connected to the lower outlet 42. The radius of the guide section 401 remains constant from top to bottom and is equal to the diameter of the upper port of the contraction section 402. The radius of the contraction section 402 decreases from top to bottom, while the radius of the diffuser section 404 increases from top to bottom. The radius of the throat section 403 is equal to the diameter of the lower port of the contraction section 402 and less than or equal to the diameter of the upper port of the diffuser section 404, and the radius of the throat section 403 remains constant from top to bottom. Meanwhile, the venturi tube 4 is also provided with an air intake chamber 405 and a mixing chamber 406. The air intake port 43 is opened on the air intake chamber 405, and the air intake chamber 405 is surrounded outside the contraction section 402 and the throat section 403. The lower port of the throat section 403 is connected to the air intake chamber 405. The mixing chamber 406 is surrounded outside the diffuser section 404. The lower end of the diffuser section 404 is provided with guide ports 454 that are connected to the mixing chamber 406 at intervals along the circumference. Ordinary water flowing into the flow channel 40 from the upper inlet 41 creates a Venturi effect in the contraction section 402, throat section 403, and diffuser section 404. At the throat section 403, it draws in gas that enters the air intake chamber 405 from the air inlet 43. The gas and water flow together into the diffuser section 404 for a first mixing, and then undergo a second mixing in the mixing chamber 406. Finally, the micro-nano bubble water is formed and flows out of the Venturi tube 4 through the lower outlet 42.

[0036] Furthermore, such as Figure 5 , Figure 6 as well as Figure 7As shown, the venturi tube 4 has an upper tube 44 and a lower tube 45 coaxially fitted inside from top to bottom. The upper tube 44 is in the shape of an inverted cone, and its interior is hollow to form the constriction section 402. The bottom of the upper tube 44 extends downward along the axial direction from the lower end of the constriction section 402 to form the throat section 403. The lower tube 45 is divided into upper and lower parts. The diameter of the upper part 45a is larger than that of the lower part 45b and is used to accommodate the upper tube 44. Windows 451 are circumferentially spaced on the wall of the upper part 45a. The interior of the lower part 45b forms the diffuser section 404. The lower end of the lower tube 45 has concave notches circumferentially spaced to form the guide ports 454. Furthermore, a horizontally extending intermediate wall 452 is provided between the upper part 45a and the lower part 45b. A through hole 4520 is opened in the center of the intermediate wall 452 along the axial direction. The through hole 4520 forms the upper port of the diffuser section 404. The upper surface of the intermediate wall 452 is inclined circumferentially from the outside to the inside towards the through hole 4520, and there is a gap between the lower end of the upper tube 44 and the upper surface of the intermediate wall 452. With the above design, a contraction section 402, a throat section 403, and a diffuser section 404 for forming the Venturi effect can be constructed in the Venturi tube 4. Through the opening of the window 451 and the design of the intermediate wall 452, the lower port of the throat section 403 is connected to the air intake chamber 405 to ensure smooth gas intake. The opening of the guide port 454 formed by the notch ensures that the gas and water flow enter the mixing chamber 406 and undergo secondary mixing.

[0037] Furthermore, such as Figure 3 As shown, the brewing unit 1 includes a brewing cup 12 and a brewing plug 11 positioned vertically opposite the brewing cup 12. The brewing cup 12 is inclined relative to the vertical direction and has a push plate 13 inside. The push plate 13 is positioned along the cross-sectional direction of the brewing cup 12. In the brewing state, the push plate 13, the corresponding part of the side wall of the brewing cup 12, and the end of the brewing plug 11 together form the brewing chamber 10, and the brewing inlet 101 is opened on the end face of the brewing plug 11. In this way, the brewing chamber 10 structure is constructed in the brewing state, and micro-nano bubble water can flow into the brewing chamber 10 from top to bottom.

[0038] Furthermore, such as Figure 3 As shown, a water inlet 2 is installed on the brewing plug 11. The water inlet connector 21 of the water inlet 2 is connected to the lower water outlet 42 via the water inlet pipe 8, while the water outlet connector 22 is in fluid communication with the brewing water inlet 101. The water inlet 2 facilitates fluid communication between the lower water outlet 42 of the Venturi tube 4 and the brewing water inlet 101. Specifically, as... Figure 8As shown, the water inlet component 2 includes a bent-shaped water inlet block 20. The water inlet connector 21 is located at one end of the water inlet block 20, and the water outlet connector 22 is located at the other end. The water inlet block 20 is inserted into the cavity 110 inside the brewing plug 11 along its length. Furthermore, the water inlet block 20 has a water inlet channel (not shown) along its length for connecting the water inlet connector 21 and the water outlet connector 22. The portion of the water inlet channel containing the water outlet connector 22 extends along the length of the brewing plug 11, and the water outlet connector 22 is vertically aligned with the brewing water inlet 101. By providing a water inlet channel in the water inlet component 2, the water inlet connector 21 and the water outlet connector 22 can be connected, and the micro-nano bubble water can be better guided to the brewing water inlet 101. In other words, the water inlet component 2 simultaneously serves the functions of water connection and guidance.

[0039] Preferably, such as Figure 8 As shown, the upper part of the water inlet block 20 is provided with a first mounting block 23 for fixing to the corresponding part of the brewing plug 11. The first mounting block 23 extends along the length direction of the brewing plug 11. The lower part of the water inlet block 20 is provided with a second mounting block 24 for fixing to the other corresponding part of the brewing plug 11. The extension direction of the second mounting block 24 is perpendicular to the first mounting block 23. The first mounting block 23 and the second mounting block 24 facilitate the installation of the water inlet component 2 on the brewing plug 11, and also ensure the firmness of the installation of the water inlet component 2. In this embodiment, each mounting block is provided with a mounting hole 25. In addition, as Figure 3 As shown, the brewing plug 11 is hollow, forming a cavity 110. A connecting seat 111 protrudes from the inner bottom surface for the water outlet connector 22 of the water inlet 2 to be inserted into. The connecting seat 111 is cylindrical and extends along the length of the brewing plug 11. The brewing water inlet 101 extends along the axis of the connecting seat 111, and the water outlet connector 22 and the brewing water inlet 101 are spaced vertically along the length of the brewing plug 11. This facilitates the insertion of the water inlet 2 into the brewing plug 11 and also facilitates fluid communication between the water outlet connector 22 and the brewing water inlet 101. Furthermore, the vertical distance between the water outlet connector 22 and the brewing water inlet 101 allows micro-nano bubble water to flow relatively smoothly into the brewing chamber 10.

[0040] The term "fluid connectivity" as used in this utility model refers to the spatial relationship between two components or parts (hereinafter referred to as the first part and the second part, respectively), that is, a fluid (gas, liquid, or a mixture of both) can flow from the first part along a flow path and / or be transported to the second part. This can be a direct connection between the first part and the second part, or an indirect connection between the first part and the second part through at least one third party. The third party can be a fluid channel such as a pipe, channel, conduit, guide, hole, or groove, or a chamber or combination thereof that allows fluid to flow through.

Claims

1. A coffee machine comprising a brewing unit (1) having a brewing chamber (10) for extracting coffee powder, characterized in that, It also includes a bubble water generating device (3) for generating micro-nano bubble water. The outlet of the bubble water generating device (3) is in fluid communication with the brewing inlet (101) of the brewing chamber (10). In the brewing state, the micro-nano bubble water flows from top to bottom into the brewing chamber (10) through the brewing inlet (101).

2. The coffee machine as described in claim 1, characterized in that, The brewing chamber (10) extends at an angle relative to the vertical direction. During the brewing process, micro-nano bubble water flows from top to bottom into the lower end of the brewing chamber (10) through the brewing inlet (101).

3. The coffee machine as described in claim 1, characterized in that, The bubble water generator (3) includes a gas tank (5) and a vertically extending Venturi tube (4). The upper opening of the Venturi tube (4) is an upper inlet (41) for ordinary water to flow in, and the lower opening is a lower outlet (42) for micro-nano bubble water to flow out. The lower outlet (42) is in fluid communication with the above-mentioned brewing inlet (101), and an air inlet (43) is provided on the side wall of the Venturi tube (4) in fluid communication with the air outlet of the gas tank (5).

4. The coffee machine as described in claim 3, characterized in that, The Venturi tube (4) has a flow channel (40) extending along its length. The flow channel (40) includes, from top to bottom, a guide section (401), a contraction section (402), a throat section (403), and a diffuser section (404), and the four sections are connected sequentially. The upper port of the guide section (401) is connected to the upper inlet (41), and the lower port of the diffuser section (404) is connected to the lower outlet (42). Furthermore, the radius of the guide section (401) remains constant from top to bottom and is equal to the diameter of the upper port of the contraction section (402). The radius of the contraction section (402) decreases from top to bottom, while the radius of the diffuser section (404) increases from top to bottom. The radius of the throat section (403) is equal to the diameter of the lower port of the contraction section (402) and less than or equal to the diameter of the upper port of the diffuser section (404), and the radius of the throat section (403) remains constant from top to bottom. The venturi tube (4) is also provided with an air inlet (405) and a mixing chamber (406). The air inlet (43) is opened on the air inlet (405), and the air inlet (405) is surrounded outside the contraction section (402) and the throat section (403). The lower port of the throat section (403) is connected to the air inlet (405). The mixing chamber (406) is surrounded outside the diffusion section (404). The lower end of the diffusion section (404) is provided with guide ports (454) that are connected to the mixing chamber (406) at intervals along the circumference.

5. The coffee machine as described in claim 4, characterized in that, The venturi tube (4) has an upper tube (44) and a lower tube (45) coaxially fitted from top to bottom in its inner cavity. The upper tube (44) is shaped like an inverted cone and is hollow inside to form the aforementioned contraction section (402). The bottom of the upper tube (44) extends downward along the axial direction from the lower end of the contraction section (402) to form the aforementioned throat section (403). The lower tube (45) is divided into upper and lower parts. The diameter of the upper part (45a) is larger than that of the lower part (45b) and is used to accommodate the upper tube (44). Windows (451) are spaced apart circumferentially on the wall of the upper part (45a). The inner cavity of the lower part (45b) forms the aforementioned diffusion section (404). The lower end of the lower tube (45) has concave notches spaced apart circumferentially to form the aforementioned guide ports (454). Furthermore, a horizontally extending middle wall (452) is provided between the upper part (45a) and the lower part (45b). A through hole (4520) is opened in the center of the middle wall (452) along the axial direction. The through hole (4520) constitutes the upper port of the diffuser section (404). The upper surface of the middle wall (452) is inclined in the circumferential direction from the outside to the inside towards the through hole (4520). A gap is left between the lower end of the upper tube (44) and the upper surface of the middle wall (452).

6. The coffee machine as described in any one of claims 3 to 5, characterized in that, The bubble water generating device (3) also includes a water pump (6) and a heater (7) for heating water. The heating inlet of the heater (7) is in fluid communication with the water outlet of the water pump (6), and the heating outlet is in fluid communication with the upper inlet (41).

7. The coffee machine according to any one of claims 3 to 5, characterized in that, The brewing unit (1) includes a brewing cup (12) and a brewing plug (11) that is directly opposite the brewing cup (12). The brewing cup (12) is inclined relative to the vertical direction and has a push plate (13) inside. The push plate (13) is arranged along the cross-sectional direction of the brewing cup (12). In the brewing state, the push plate (13), the corresponding part of the side wall of the brewing cup (12) and the end of the brewing plug (11) together form the brewing chamber (10). The brewing water inlet (101) is opened on the end face of the brewing plug (11).

8. The coffee machine as described in claim 7, characterized in that, The brewing plug (11) is equipped with a water inlet (2), the water inlet connector (21) of which is connected to the lower water outlet (42) via the water inlet pipe (8), and the water outlet connector (22) is in fluid communication with the brewing water inlet (101).

9. The coffee machine as described in claim 8, characterized in that, The water inlet component (2) includes a water inlet block (20) with a bent shape. The water inlet connector (21) is located at one end of the water inlet block (20) and the water outlet connector (22) is located at the other end of the water inlet block (20). The water inlet block (20) is inserted into the cavity (110) inside the brewing plug (11) along the length direction of the brewing plug (11). The water inlet block (20) has a water inlet channel along its own length direction for connecting the water inlet connector (21) and the water outlet connector (22). The part of the water inlet channel where the water outlet connector (22) is located extends along the length direction of the brewing plug (11), and the water outlet connector (22) is arranged vertically opposite to the brewing water inlet (101).

10. The coffee machine as described in claim 9, characterized in that, The upper part of the water inlet block (20) is provided with a first mounting block (23) for fixing to the corresponding part of the brewing plug (11). The first mounting block (23) extends along the length direction of the brewing plug (11). The lower part of the water inlet block (20) is provided with a second mounting block (24) for fixing to the other corresponding part of the brewing plug (11). The extension direction of the second mounting block (24) is perpendicular to the first mounting block (23).

11. The coffee machine as described in claim 9, characterized in that, The brewing plug (11) is hollow inside to form the cavity (110), and a connecting seat (111) is provided on the inner bottom surface for the water outlet connector (22) of the water inlet (2) to be inserted. The connecting seat (111) is cylindrical in shape and extends along the length direction of the brewing plug (11), while the brewing water inlet (101) extends along the axial direction of the connecting seat (111), and the water outlet connector (22) and the brewing water inlet (101) are spaced vertically along the length direction of the brewing plug (11).

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