Piston type gravity self-discharging coffee machine pipeline device and method

Abstract

The invention discloses a piston type gravity self-discharging coffee machine pipeline device and method. The piston type gravity self-discharging coffee machine pipeline device comprises a frame, a brewing cylinder movably arranged in the frame, an upper piston fixedly arranged on the frame and a driving mechanism for driving the brewing cylinder to reciprocate. A lower piston in sliding sealing fit with the inner wall of the brewing cylinder is arranged in the brewing cylinder, the bottom of the lower piston is connected with a liquid outlet plug extending downwards, a liquid outlet is formed in the side wall of the liquid outlet plug, and the outer wall of the liquid outlet plug is sleeved with a sealing ring; the device further comprises a fixedly-arranged liquid outlet connector, and the liquid outlet connector is provided with an inner cavity allowing the liquid outlet plug to be axially inserted. Accurate switching of the liquid outlet connector between the sealed extraction position and the gravity self-discharging position is achieved through cooperation of the driving mechanism and the guide limiting mechanism, the extraction sealing performance can be guaranteed so that the coffee quality can be improved, a pipeline can be thoroughly emptied without additional power, meanwhile, the structure is simplified, the cost is reduced, and the reliability and comprehensive performance of equipment are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coffee machines, in particular to a piston type gravity self-draining coffee machine pipeline device and method. BACKGROUND

[0002] With the continuous improvement of people's pursuit of life quality, full-automatic and semi-automatic coffee machines have been widely used in families, offices and commercial places due to their convenience and the ability to make high-quality coffee. Among them, the coffee machine using the piston type pressure extraction principle can simulate the pressure extraction process of professional Italian coffee machines through the cooperation of the upper and lower pistons and the brewing cylinder, so as to obtain concentrated coffee with rich oil and rich flavor, which is favored by the market.

[0003] In the existing design of coffee machines, especially in low-end products, in order to control the cost, an effective pipeline liquid accumulation removal mechanism is usually lacking. After the coffee making is finished, part of the coffee liquid will inevitably remain in the internal pipeline. These accumulated liquids are difficult to completely drain and will mix with the newly prepared coffee when making the next cup of coffee. Not only can it produce odor due to long-term retention, destroy the original taste and concentration balance of coffee, but also directly affect the stability of coffee quality and the best presentation of coffee bean flavor. Although some high-end models add a drain pump to solve this problem, they significantly increase the production cost and structural complexity, making it difficult to popularize and apply.

[0004] Therefore, a piston type gravity self-draining coffee machine pipeline device and method are proposed to solve the problems mentioned above. SUMMARY

[0005] The purpose of the present application is to provide a piston type gravity self-draining coffee machine pipeline device and method to solve the problem of lack of cost-effective pipeline liquid accumulation removal mechanism in the existing design of coffee machines, which affects the quality and flavor stability of the residual coffee liquid.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a piston type gravity self-draining coffee machine pipeline device and method, comprising a frame, a brewing cylinder movably arranged inside the frame, an upper piston fixedly arranged on the frame, and a driving mechanism for driving the brewing cylinder to reciprocate, The brewing cylinder is provided with a lower piston in sliding sealing cooperation with the inner wall thereof. The bottom of the lower piston is connected with a downwardly extending liquid outlet plug. The side wall of the liquid outlet plug is provided with a liquid outlet. The outer wall of the liquid outlet plug is provided with a sealing ring; The device further comprises a fixedly arranged liquid outlet connector. The liquid outlet connector is provided with an inner cavity for axial insertion of the liquid outlet plug; The liquid outlet plug can move axially relative to the liquid outlet connector and has a first position and a second position: In the first position, the liquid outlet plug is inserted into the inner cavity of the liquid outlet connector to a preset depth, the sealing ring is sealed and fitted against the inner cavity wall of the liquid outlet connector, and at the same time the liquid outlet is located in the inner cavity and communicates with the drain port of the liquid outlet connector to form a sealed drain channel. In the second position, the liquid outlet plug is axially withdrawn relative to the liquid outlet connector, causing the sealing ring to disengage from the sealing fit with the inner wall of the liquid outlet connector, and the liquid outlet moves outside the inner opening end of the liquid outlet connector, thereby allowing the inner cavity of the liquid outlet connector to directly communicate with the external environment through its opening end.

[0007] Preferably, the liquid outlet plug has a drainage cavity that communicates with the inside of the brewing tank, and the liquid outlet is connected to the drainage cavity; a one-way valve structure is provided in the drainage cavity above the liquid outlet to guide the coffee liquid from the brewing tank into the drainage cavity.

[0008] Preferably, the one-way valve structure includes a valve core, a return spring, and a flow guide; a stepped surface is formed in the drainage cavity; the valve core is slidably disposed in the drainage cavity; one end of the return spring abuts against the stepped surface, and the other end acts on the valve core, causing it to tend to move towards the bottom of the drainage cavity; the flow guide is fixed to the upper port of the liquid outlet plug and fits against the end of the valve core, together sealing the top of the drainage cavity under normal conditions.

[0009] Preferably, a partition is fixedly connected to one side of the center of the frame, and the driving mechanism is disposed on one side of the partition. The driving mechanism includes a driving screw and a threaded sleeve. The driving screw is rotatably connected to the side wall of the frame through a bearing. The threaded sleeve is threadedly connected to the driving screw.

[0010] Preferably, a driven slider is fixedly connected to the outer side of the threaded sleeve, and guide sliders are fixedly connected to both ends of the driven slider. A slider guide groove is provided on the inner side wall of the frame to slide with the guide slider. A protective sleeve is fixedly connected to one side of the driven slider through the partition, and the inner cavity of the protective sleeve is fixedly connected to the brewing cylinder.

[0011] Preferably, the bottom end of the lower piston is connected to a piston connecting rod, and a longitudinal guide groove is provided on the frame. The piston connecting rod slides in conjunction with the longitudinal guide groove to limit the rotation of the lower piston and constrain its vertical movement stroke.

[0012] Preferably, the liquid outlet connector is fixed to the bottom of the protective sleeve by bolts, and a coffee tube is snapped into the drain port of the liquid outlet connector.

[0013] Preferably, the upper piston is fixed to the frame and located directly above the movement trajectory of the brewing cylinder. When the brewing cylinder moves upward to a predetermined position, the bottom of the upper piston extends into the top opening of the brewing cylinder and forms a sliding seal with its inner wall.

[0014] Preferably, the outer side of the protective sleeve is provided with an axial guide rib, which cooperates with the feed hopper rotatably disposed on the frame. When the protective sleeve drives the brewing cylinder to rise to a set height, the axial guide rib pushes the feed hopper to rotate to the open state.

[0015] The present invention also provides a method for gravity self-draining of coffee machine tubing using the aforementioned piston-type gravity self-draining coffee machine tubing device, comprising the following steps: S1. Coffee powder loading step: Coffee powder is loaded into the cavity formed by the brewing tank and the lower piston located at the bottom of it; S2. Brewing and extraction steps: Drive the brewing cylinder to rise, so that its top opening connects with the upper piston to form a sealed brewing chamber; inject hot water into the brewing chamber to extract coffee, and the extracted coffee liquid is discharged sequentially through the liquid outlet of the liquid outlet plug and the liquid drain of the liquid outlet connector. S3. Gravity self-discharge step: After extraction, the brewing cylinder is driven downward to separate it from the upper piston; during the descent, the lower piston first descends with the brewing cylinder until it is blocked by the limiting structure on the frame and stops moving; the brewing cylinder continues to descend, causing the liquid outlet plug to move upward relative to the liquid outlet connector, so that the liquid outlet plug switches from the first position to the second position, and the sealing ring disengages from the inner wall of the liquid outlet connector; at this time, the inner cavity of the liquid outlet connector is directly connected to the external environment through its open end, and the residual coffee liquid in the pipeline is automatically discharged under the action of gravity.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This piston-type gravity self-draining coffee machine pipeline device and method, through the coordinated action of a drive and guide limiting mechanism, achieves precise switching of the liquid outlet connector between the sealed extraction and gravity self-draining positions. This ensures extraction sealing to improve coffee quality, while completely emptying the pipeline without additional power. Simultaneously, it simplifies the structure, reduces costs, and improves equipment reliability and overall performance. The specific details are as follows: Firstly, through the coordinated action of the drive mechanism and the guide limiting mechanism, the liquid outlet plug and connector can be precisely switched between the sealed drainage position (first position) and the gravity self-draining position (second position). During the extraction stage, a sealed flow channel is formed to ensure that the concentration and taste of the coffee liquid are not affected. After extraction, the sealing ring detaches from the inner wall of the liquid outlet connector to form an open passage. With the help of gravity, the residual coffee liquid in the pipeline can be completely emptied, thus avoiding the problems of liquid accumulation causing off-flavors and damaging the original taste and concentration balance of the coffee. This ensures that every cup of coffee accurately presents the best flavor of the coffee beans, greatly improving the consistency of coffee quality. At the same time, this gravity self-draining structure does not require additional power components such as an emptying pump. Compared with the liquid removal solution of high-end models, it greatly simplifies the complexity of the equipment structure, effectively controls production costs, and facilitates its widespread application in mid-to-low-end models, taking into account both quality improvement and market promotion value.

[0017] Secondly, an outlet is opened on the side wall of the liquid outlet plug and a sealing ring is fitted on its outer wall. In the first position, a tight sealed drainage channel can be formed to prevent coffee liquid leakage and ensure the sealing of the extraction process and the efficiency of coffee liquid output. The drainage cavity is equipped with a one-way valve structure consisting of a valve core pre-tightened by a return spring and a flow guide. Under normal conditions, it fits against the flow guide and seals the top of the drainage cavity, further enhancing the sealing effect and avoiding leakage or pressure loss during extraction. At the same time, it guides the coffee liquid to flow into the drainage cavity in one direction. Furthermore, the device utilizes a drive mechanism consisting of a drive screw, threaded sleeve, driven slider, and guide slider with guide groove, as well as a guide limiting mechanism consisting of a piston connecting rod and longitudinal guide groove. This enables orderly movement control of the brewing cylinder and the lower piston, with precise and controllable stroke and smooth component cooperation, effectively extending the equipment's service life. Additionally, the structure can be linked with the feed hopper via axial guide ribs on the outer side of the protective sleeve. When the brewing cylinder rises to a set height, the feed hopper is rotated to the open position, improving the overall coordination of the equipment's operation. Compared to traditional structures, it offers superior comprehensive performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the frame in this invention; Figure 3 This is a schematic diagram of the brewing tank in its initial position in this invention. Figure 4 For the present invention Figure 1 A schematic diagram of the bottom structure viewed from below; Figure 5 This is a schematic cross-sectional view of the overall structure of the present invention; Figure 6 For the present invention Figure 5 A schematic diagram of the brewing chamber structure formed when the middle brewing cylinder rises and forms a brewing chamber between it and the upper piston; Figure 7 For the present invention Figure 5 A schematic diagram of the brewing tank in its lowest position; Figure 8 For the present invention Figure 6 Enlarged structural diagram at point A in the middle; Figure 9 This is a schematic diagram of the liquid outlet plug and liquid outlet connector in the installation state of the present invention.

[0019] In the diagram: 1. Frame; 101. Slider guide groove; 102. Longitudinal guide groove; 2. Partition plate; 3. Drive screw; 4. Threaded sleeve; 5. Driven slider; 501. Guide slider; 6. Protective sleeve; 601. Axial guide rib; 7. Brewing cylinder; 8. Upper piston; 9. Feed hopper; 10. Lower piston; 11. Piston connecting rod; 12. Discharge plug; 1201. Drain cavity; 1202. Discharge port; 1203. Sealing ring; 1204. Return spring; 1205. Valve core; 1206. Flow guide; 13. Discharge connector; 14. Coffee conduit. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0021] like Figures 1-9 As shown, the present invention provides a piston-type gravity self-draining coffee machine pipeline device. This device includes a frame 1, a brewing cylinder 7, an upper piston 8, a drive mechanism, a lower piston 10, a liquid outlet plug 12, a liquid outlet connector 3, and matching connecting parts. These components work together to achieve coffee extraction and gravity self-draining of residual liquid in the pipeline. The specific structure is as follows: like Figures 1-2 As shown, frame 1 serves as the installation reference for the entire device, providing support and installation space for the internal components. A partition 2 is fixedly connected to one side of the center inside frame 1. This partition 2 divides the interior of frame 1 into two independent areas. One area is used to arrange the drive mechanism, and the other area is used to install the brewing tank 7 and its matching draining components. This achieves the partitioned arrangement of the drive components and the operating components, improving the operational stability of the device and facilitating maintenance.

[0022] like Figure 3As shown, the drive mechanism is used to drive the brewing cylinder 7 to reciprocate in the vertical direction. Specifically, it includes a drive screw 3 and a threaded sleeve 4. The drive screw 3 is rotatably connected to the corresponding side wall of the frame 1 via bearings. The bearings ensure that the drive screw 3 can rotate flexibly while maintaining a fixed axial position. The threaded sleeve 4 forms a threaded transmission engagement with the drive screw 3. The forward and reverse rotation of the drive screw 3 drives the threaded sleeve 4 to move axially along the drive screw 3. To prevent the threaded sleeve 4 from rotating synchronously with the drive screw 3, a driven slider 5 is fixedly connected to the outside of the threaded sleeve 4. Guide sliders 501 are integrally formed or fixedly connected to both ends of the driven slider 5. Correspondingly, a slider guide groove 101 is provided on the inner side wall of the frame 1. The guide slider 501 is embedded in the slider guide groove 101 and forms a sliding engagement. Through the limiting effect of the slider guide groove 101 on the guide slider 501, the threaded sleeve 4 is constrained to only reciprocate linearly along the axial direction of the drive screw 3, eliminating rotational interference.

[0023] A protective sleeve 6 is fixedly connected to one side of the driven slider 5 through a through hole in the partition 2. The protective sleeve 6 is made of corrosion-resistant, high-strength metal or engineering plastic, and its inner cavity is fixedly connected to the outer wall of the brewing tank 7 to ensure that the protective sleeve 6 moves synchronously with the brewing tank 7. The protective sleeve 6 not only serves as a fixed connection but also protects the brewing tank 7 from collisions and wear with other components during movement. At the same time, it can conceal the internal connection structure, improving the overall aesthetics of the device.

[0024] like Figure 2 The upper piston 8 is fixed to the frame 1 by a bracket or bolts and is located directly above the movement trajectory of the brewing cylinder 7. The outer diameter of the upper piston 8 is adapted to the inner diameter of the brewing cylinder 7. When the drive mechanism moves the brewing cylinder 7 upward to the predetermined position, the bottom of the upper piston 8 can accurately extend into the top opening of the brewing cylinder 7, and the outer wall of the upper piston 8 forms a sliding seal with the inner wall of the brewing cylinder 7, thereby forming a sealed brewing chamber inside the brewing cylinder 7, providing a sealed environment for coffee extraction.

[0025] like Figures 5-8As shown, a lower piston 10 is movably mounted inside the brewing tank 7. The outer diameter of the lower piston 10 is adapted to the inner wall of the brewing tank 7, and the two are slidably sealed together. A piston rod 11 is engaged with the bottom end of the lower piston 10. Correspondingly, a longitudinal guide groove 102 is provided on the frame 1. The lower end of the piston rod 11 passes through the longitudinal guide groove 102 and forms a sliding fit with the guide groove. This structure can restrict the lower piston 10 from rotating around its own axis and also constrain the lower piston 10 to move only in the vertical direction. At the same time, the length of the longitudinal guide groove 102 limits the vertical stroke of the lower piston 10, preventing excessive movement that could damage the components. When the piston rod 11 is at the bottom of the frame 1, it is in a locked and fixed state. This locking and fixing structure can be achieved by a snap-fit ​​and slot matching method, ensuring that the lower piston 10 and the liquid outlet plug 12 remain stable in their respective positions.

[0026] A downward-extending outlet plug 12 is fixedly connected to the center of the bottom of the lower piston 10. The outlet plug 12 and the lower piston 10 can be integrally molded to improve structural strength and sealing. An outlet cavity 1201 is provided inside the outlet plug 12. This outlet cavity 1201 extends axially along the outlet plug 12 and communicates with the interior of the brewing tank 7 (the brewing chamber above the lower piston 10) to guide the brewed coffee liquid downwards. An outlet 1202 is provided on the side wall of the outlet plug 12, communicating with the outlet cavity 1201. A sealing ring 1203 is fitted on the outer wall of the outlet plug 12. The sealing ring 1203 is made of food-grade silicone or fluororubber, possessing good sealing performance, temperature resistance, and corrosion resistance, and is used to achieve a sealed fit between the outlet plug 12 and the outlet connector 13. The number of sealing rings 1203 is preferably two, which are respectively set on the upper and lower sides of the liquid outlet 1202 on the outer wall of the liquid outlet plug 12 to ensure the sealing performance in the sealed state and prevent coffee liquid leakage.

[0027] To achieve directional discharge of coffee liquid and subsequent gravity self-drainage, the device also includes a fixedly installed dispensing connector 13. The dispensing connector 13 is fixed to the bottom of the protective sleeve 6 by bolts, and its position corresponds to the axis of the dispensing plug 12. The dispensing connector 13 has an inner cavity, the inner diameter of which is adapted to the outer diameter of the dispensing plug 12, allowing the dispensing plug 12 to be inserted axially. A drain port is provided on one side of the dispensing connector 13, and a coffee conduit 14 is snapped into the drain port. The coffee conduit 14 is made of food-grade soft tubing or rigid tubing and is used to guide the extracted coffee liquid to the receiving cup position. The snap-fit ​​connection facilitates the disassembly and cleaning of the coffee conduit 14.

[0028] To prevent coffee liquid from flowing back, a one-way valve structure is installed in the drain cavity 1201 above the outlet 1202. This one-way valve structure only allows coffee liquid to enter the drain cavity 1201 from the brewing tank 7, while preventing coffee liquid from flowing back into the brewing chamber, thus ensuring the stability of the extraction process. Specifically, the one-way valve structure includes a valve core 1205, a return spring 1204, and a flow guide 1206; a stepped surface is formed in the drainage cavity 1201, which serves as the mounting reference for the return spring 1204; the valve core 1205 is slidably disposed in the drainage cavity 1201, and the top end of the valve core 1205 is a sealing end, which cooperates with the flow guide 1206 to achieve a seal; the return spring 1204 is sleeved on the outside of the valve core 1205, one end of which abuts against the stepped surface in the drainage cavity 1201, and the other end acts on the shoulder of the valve core 1205, providing an elastic force for the valve core 1205 to move toward the bottom of the drainage cavity 1201; the flow guide 1206... The 206 is snap-fitted or interference-fitted to the upper port of the liquid outlet plug 12. The bottom of the flow guide 1206 is attached to the end of the valve core 1205. Under normal conditions (when there is no extraction pressure), the return spring 1204 pushes the valve core 1205 to press the flow guide 1206, which together seals the top of the drain cavity 1201 and prevents external air or liquid from entering. When extraction pressure is generated in the brewing chamber, the coffee liquid pushes the valve core 1205 to overcome the elastic force of the return spring 1204 and move downward, causing the valve core 1205 to separate from the flow guide 1206, forming a gap. The coffee liquid enters the drain cavity 1201 through this gap and is then discharged through the liquid outlet 1202.

[0029] In addition, an axial guide rib 601 is provided on the outer side of the protective sleeve 6. The axial guide rib 601 can be integrally formed with the protective sleeve 6, and its extension direction is consistent with the axial direction of the protective sleeve 6. The axial guide rib 601 cooperates with the feed hopper 9 rotatably mounted on the frame 1 to realize the automatic opening and closing of the feed hopper 9. When the protective sleeve 6 drives the brewing cylinder 7 to rise to the set height, the axial guide rib 601 contacts the linkage structure of the feed hopper 9 and pushes the feed hopper 9 to rotate to the open state, which facilitates the loading of coffee powder into the brewing cylinder 7; when the protective sleeve 6 drives the brewing cylinder 7 to descend, the axial guide rib 601 disengages from the feed hopper 9, and the feed hopper 9 rotates to the closed state under its own weight or the action of the reset structure, preventing foreign objects from entering the brewing chamber during the extraction process.

[0030] like Figures 6-7 As shown, the liquid outlet plug 12 can move axially relative to the liquid outlet connector 13, and the function of liquid discharge and self-drainage can be switched by switching the position. Specifically, it has a first position (liquid discharge position) and a second position (self-drainage position). The structural states and functions of the two positions are as follows: In the first position, the brewing cylinder 7 is in the rising state, and the upper piston 8 docks with the brewing cylinder 7 to form a sealed brewing chamber. At this time, the dispensing plug 12 is inserted into the inner cavity of the dispensing connector 13 to a preset depth. In this state, the sealing ring 1203 on the outer wall of the dispensing plug 12 is tightly sealed to the inner wall of the dispensing connector 13, forming a circumferential seal to prevent coffee leakage. At the same time, the dispensing port 1202 on the side wall of the dispensing plug 12 is completely located in the inner cavity of the dispensing connector 13 and is in communication with the drain port of the dispensing connector 13, thereby forming a sealed drainage channel from the brewing chamber—drainage cavity 1201—drain port 1202—inner cavity of the dispensing connector 13—drain port—coffee conduit 14, ensuring that the extracted coffee can be discharged directionally along this channel without leakage or overflow.

[0031] In the second position, the extraction process ends, and the drive mechanism moves the brewing cylinder 7 downward, separating it from the upper piston 8. During the descent of the brewing cylinder 7, the lower piston 10 first descends synchronously with the brewing cylinder 7 under its own weight and the constraint of the piston connecting rod (11), until the piston connecting rod 11 is blocked by the limiting structure on the frame 1 (such as the limiting block at the top of the longitudinal guide groove 102, the support block at the bottom of the frame 1, etc.) and stops moving. At this time, the brewing cylinder 7 continues to descend under the drive of the drive mechanism. Since the lower piston 10 has stopped moving, the brewing cylinder 7 moves the liquid outlet plug 12 upward relative to the liquid outlet connector 13, so that the liquid outlet plug 12 gradually switches from the first position to the second position. In this state, the sealing ring 1203 on the outer wall of the dispensing plug 12 completely disengages from the sealing fit with the inner wall of the dispensing connector 13, and the sealing state is released. At the same time, the dispensing port 1202 on the side wall of the dispensing plug 12 moves upward with the dispensing plug 12 and eventually ends outside the inner opening of the dispensing connector 13, allowing the inner cavity of the dispensing connector 13 to be directly connected to the external environment through its upper opening. At this time, the coffee liquid remaining in the coffee conduit 14, the inner cavity of the dispensing connector 13, and related pipelines flows downward along the pipeline under its own gravity and is finally discharged through the opening of the dispensing connector 13 to an external collection structure (such as a waste liquid tray), realizing the gravity self-drainage of the residual liquid in the pipeline without the need for additional power drive, which is simple in structure and energy-efficient.

[0032] When the liquid outlet connector 13 and the liquid outlet plug 12 need to be reconnected after separation, the drive mechanism moves the brewing cylinder 7 upward, which in turn moves the liquid outlet connector 13, which is fixed to the bottom of the protective sleeve 6, upward simultaneously. At this time, because the piston connecting rod 11 is in the locked state at the bottom of the frame 1, the liquid outlet plug 12 remains fixed. After the liquid outlet plug 12 and the liquid outlet connector 13 are fully aligned and sealed, the brewing cylinder 7 returns to its initial position. Then, the piston connecting rod 11 is released from the locked state and moves upward with the brewing cylinder 7, entering the preparation stage for the next round of extraction.

[0033] Based on the above-mentioned piston-type gravity self-draining coffee machine tubing device, the present invention also discloses a corresponding gravity self-draining method for coffee machine tubing, which specifically includes the following steps: S1. Coffee Powder Loading Step: First, the brewing cylinder 7 is driven downwards to its initial position by the drive mechanism. At this time, the upper piston 8 is completely separated from the brewing cylinder 7, and the feed hopper 9 is in the open state. A preset amount of coffee powder is loaded into the cavity formed by the brewing cylinder 7 and the lower piston 10 located at its bottom. After loading, the brewing cylinder 7 is driven to rise slightly, and the axial guide rib 601 drives the feed hopper 9 to rotate to the closed state to prevent coffee powder leakage or foreign objects from entering during the extraction process.

[0034] S2. Brewing and extraction steps: Start the drive mechanism, drive the screw 3 to rotate forward, drive the threaded sleeve 4, driven slider 5 and protective sleeve 6 to move upward synchronously through the thread transmission, and then drive the brewing cylinder 7 to move upward. When the brewing cylinder 7 rises to the predetermined position, the bottom of the upper piston 8 extends into the top opening of the brewing cylinder 7 and forms a sliding seal with its inner wall, forming a closed brewing chamber. Then, hot water at a preset temperature and pressure is injected into the closed brewing chamber, and the hot water fully contacts the coffee powder and carries out the extraction reaction. Under the action of the extraction pressure, the extracted coffee liquid pushes the valve core 1205 of the one-way valve structure to move downward, overcomes the elasticity of the return spring 1204 and separates the valve core 1205 from the guide cover 1206. The coffee liquid enters the drain cavity 1201, then flows into the inner cavity of the outlet connector 13 through the outlet 1202, and finally is discharged into the cup receiving device through the outlet of the outlet connector 13 and the coffee conduit (14), completing the coffee extraction and drainage.

[0035] S3. Gravity Self-Draining Step: After coffee extraction is complete, the drive mechanism is activated, driving screw 3 to reverse, causing threaded sleeve 4, driven slider 5, protective sleeve 6, and brewing cylinder 7 to descend synchronously, separating brewing cylinder 7 from upper piston 8 and releasing the sealed state of the brewing chamber. In the initial stage of brewing cylinder 7's descent, lower piston 10 descends synchronously with brewing cylinder 7 under its own gravity and the constraint of piston connecting rod 11, until piston connecting rod 11 contacts and is blocked by the limiting structure on frame 1, at which point lower piston 10 stops moving. Brewing cylinder 7 continues to descend under the continuous drive of the drive mechanism. Since lower piston 10 remains stationary, brewing cylinder 7 causes dispensing plug 12 to move upward relative to dispensing connector 13, switching dispensing plug 12 from the first position (draining position) to the second position (self-draining position). At this point, the sealing ring 1203 on the outlet plug 12 disengages from the inner wall of the outlet connector 13, and the outlet 1202 moves outside the opening end of the inner cavity of the outlet connector 13. The inner cavity of the outlet connector 13 communicates with the external environment through its opening end. The coffee liquid remaining in the coffee conduit 14, the inner cavity of the outlet connector 13, and the drain channel automatically flows downward under its own gravity and is discharged through the opening end of the outlet connector 13 to the external waste liquid collection structure, achieving thorough removal of residual liquid in the pipeline. After self-draining is completed, the drive mechanism drives the brewing tank 7 back to the initial position, preparing for the next extraction operation.

[0036] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A piston-type gravity-fed self-draining coffee machine piping device, comprising a frame (1), a brewing cylinder (7) movably disposed inside the frame (1), an upper piston (8) fixedly disposed on the frame (1), and a drive mechanism for driving the brewing cylinder (7) to reciprocate, characterized in that: The brewing tank (7) is provided with a lower piston (10) that slides and seals with its inner wall. The bottom of the lower piston (10) is connected to a downwardly extending liquid outlet plug (12). The side wall of the liquid outlet plug (12) is provided with a liquid outlet (1202), and its outer wall is fitted with a sealing ring (1203). The device also includes a fixedly installed liquid outlet connector (13), which has an inner cavity for the liquid outlet plug (12) to be inserted axially. The liquid outlet plug (12) is axially movable relative to the liquid outlet connector (13) and has a first position and a second position: In the first position, the liquid outlet plug (12) is inserted into the inner cavity of the liquid outlet connector (13) to a preset depth, the sealing ring (1203) is sealed and fitted with the inner cavity wall of the liquid outlet connector (13), and at the same time the liquid outlet (1202) is located in the inner cavity and communicates with the drain port of the liquid outlet connector (13) to form a sealed drain channel; In the second position, the liquid outlet plug (12) is axially withdrawn relative to the liquid outlet connector (13), causing the sealing ring (1203) to disengage from the sealing fit with the inner wall of the liquid outlet connector (13), and the liquid outlet (1202) moves to outside the inner opening end of the liquid outlet connector (13), thereby allowing the inner cavity of the liquid outlet connector (13) to be directly connected to the external environment through its opening end.

2. The piston-type gravity self-draining coffee machine piping device according to claim 1, characterized in that: The liquid outlet plug (12) has a drain cavity (1201) that communicates with the inside of the brewing tank (7), and the liquid outlet (1202) communicates with the drain cavity (1201). A one-way valve structure is provided in the drain cavity (1201) above the liquid outlet (1202) to guide the coffee liquid from the brewing tank (7) into the drain cavity (1201).

3. The piston-type gravity self-draining coffee machine piping device according to claim 2, characterized in that: The one-way valve structure includes a valve core (1205), a return spring (1204), and a flow guide (1206); a stepped surface is formed in the drain cavity (1201); the valve core (1205) is slidably disposed in the drain cavity (1201); one end of the return spring (1204) abuts against the stepped surface, and the other end acts on the valve core (1205), causing it to tend to move toward the bottom of the drain cavity (1201); the flow guide (1206) is fixed to the upper port of the liquid outlet plug (12) and fits against the end of the valve core (1205), together sealing the top of the drain cavity (1201) under normal conditions.

4. The piston-type gravity self-draining coffee machine piping device according to claim 1, characterized in that: A partition (2) is fixedly connected to one side of the center of the frame (1). The driving mechanism is located on one side of the partition (2). The driving mechanism includes a driving screw (3) and a threaded sleeve (4). The driving screw (3) is rotatably connected to the side wall of the frame (1) through a bearing. The threaded sleeve (4) is threadedly connected to the driving screw (3).

5. A piston-type gravity self-draining coffee machine piping device according to claim 4, characterized in that: The outer side of the threaded sleeve (4) is fixedly connected to a driven slider (5), and the two ends of the driven slider (5) are fixedly connected to guide sliders (501). The inner side wall of the frame (1) is provided with a slider guide groove (101) that slides with the guide slider (501). One side of the driven slider (5) passes through the partition (2) and is fixedly connected to a protective sleeve (6). The inner cavity of the protective sleeve (6) is fixedly connected to the brewing tank (7).

6. The piston-type gravity self-draining coffee machine piping device according to claim 1, characterized in that: The bottom end of the lower piston (10) is connected to a piston rod (11), and a longitudinal guide groove (102) is provided on the frame (1). The piston rod (11) slides in cooperation with the longitudinal guide groove (102) to limit the rotation of the lower piston (10) and constrain its vertical movement stroke.

7. A piston-type gravity-fed self-draining coffee machine piping device according to claim 1, characterized in that: The liquid outlet connector (13) is fixed to the bottom of the protective sleeve (6) by bolts, and a coffee tube (14) is snapped into the outlet of the liquid outlet connector (13).

8. The piston-type gravity self-draining coffee machine piping device according to claim 1, characterized in that: The upper piston (8) is fixed on the frame (1) and located directly above the movement trajectory of the brewing cylinder (7). When the brewing cylinder (7) moves upward to the predetermined position, the bottom of the upper piston (8) extends into the top opening of the brewing cylinder (7) and forms a sliding seal with its inner wall.

9. A piston-type gravity-fed self-draining coffee machine piping device according to claim 7, characterized in that: The outer side of the protective sleeve (6) is provided with an axial guide rib (601). The axial guide rib (601) cooperates with the feed hopper (9) which is rotatably provided on the frame (1). When the protective sleeve (6) drives the brewing cylinder (7) to rise to a set height, the axial guide rib (601) pushes the feed hopper (9) to rotate to the open state.

10. A method for gravity-driven self-discharge of coffee machine tubing using a piston-type gravity-driven self-discharge device as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Filling step: Fill the cavity formed by the brewing tank (7) and the lower piston (10) located at the bottom of it with coffee powder; S2. Brewing and extraction steps: drive the brewing cylinder (7) to rise, so that its top opening connects with the upper piston (8) to form a closed brewing chamber; inject hot water into the brewing chamber to extract coffee, and the extracted coffee liquid is discharged through the outlet (1202) of the outlet plug (12) and the drain port of the outlet connector (13) in sequence. S3. Gravity self-discharge step: After extraction, the brewing cylinder (7) is driven to descend, separating it from the upper piston (8); during the descent, the lower piston (10) descends with the brewing cylinder (7) until it is blocked by the limiting structure on the frame (1) and stops moving; the brewing cylinder (7) continues to descend, driving the liquid outlet plug (12) to move upward relative to the liquid outlet connector (13), so that the liquid outlet plug (12) switches from the first position to the second position, and the sealing ring (1203) disengages from the inner wall of the liquid outlet connector (13); at this time, the inner cavity of the liquid outlet connector (13) is directly connected to the external environment through its open end, and the residual coffee liquid in the pipeline is automatically discharged under the action of gravity.

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