Pipe system for a coffee machine and coffee machine thereof

Abstract

The present application relates to the technical field of coffee equipment, and particularly relates to a pipeline system for a coffee machine and the coffee machine thereof, which comprises a heating assembly, a flow detection assembly and a pressure detection assembly. The heating assembly is internally provided with a heating pipe and a water outlet. The flow detection assembly is arranged downstream of the water outlet. The pressure detection assembly is connected to the pipeline between the downstream of the flow detection assembly and an extraction cavity through a tee structure. The first port of the pressure detection assembly is connected to the downstream pipeline of the flow detection assembly. The second port of the pressure detection assembly is connected to the inlet of the extraction cavity. The third port of the pressure detection assembly is connected to the pressure detection assembly. A blocking structure is arranged between the water outlet and the bubble generation area of the heating pipe. The blocking structure is located on the path of the bubbles moving from the bubble generation area to the water outlet. The present application can solve the technical problem that there is a large deviation between the measured flow value and pressure value and the actual situation of the extraction cavity in the variable pressure extraction system.

Description

Technical Field

[0001] This invention relates to the field of coffee equipment technology, and more particularly to a piping system for a coffee machine and the coffee machine thereof. Background Technology

[0002] A coffee machine is a device that uses pressure to extract coffee grounds from heated water at a suitable temperature to make coffee beverages. In recent years, pressure swing extraction (PSI) technology has gradually become an important development direction in the coffee machine industry. It dynamically changes the extraction pressure during the coffee extraction process through methods such as adjusting the water pump speed or controlling the valve body to adapt to the extraction characteristics of different coffee beans, thereby obtaining a richer coffee flavor. In a PSI system, the operating status of the water pump (such as speed and frequency) continuously changes during the extraction process, and the heating process is also dynamically adjusted accordingly to achieve coordinated control of extraction temperature and pressure.

[0003] In pressure swing extraction (PSA) systems, the accurate measurement of water volume and extraction pressure directly impacts the precision and consistency of coffee output. However, commercially available products have been found to have significant and unstable flow rate readings that deviate considerably from the actual flow rate, leading to substantial discrepancies between the actual extracted water volume and the user's settings. Furthermore, the measured pressure values ​​also show a marked difference from the actual pressure within the extraction chamber. These factors collectively result in relatively inconsistent coffee output from PSA systems. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention proposes a piping system for a coffee machine and a coffee machine thereof, which can solve the technical problem that there is a large deviation between the measured flow and pressure values ​​in the pressure swing extraction system and the actual situation of the extraction chamber.

[0005] To achieve this objective, the present invention adopts the following technical solution: This invention provides a piping system for a coffee machine, including a heating assembly with a heating tube and a water inlet. The water inlet is used to draw water heated by the heating tube. A flow detection assembly is located downstream of the water inlet and is used to detect the amount of water flowing through the water path. A pressure detection assembly is connected to the pipeline downstream of the flow detection assembly and the extraction chamber via a T-junction. The first port of the T-junction is connected to the downstream pipeline of the flow detection assembly, the second port is connected to the inlet of the extraction chamber, and the third port is connected to the pressure detection assembly. A barrier structure is provided between the water inlet and the bubble-generating area of ​​the heating tube. The barrier structure is located on the path of the bubbles moving from the bubble-generating area to the water inlet. It should be noted that the term "barrier structure" broadly refers to a structural arrangement between the water inlet and the bubble-generating area of ​​the heating tube that deviates the water inlet from the bubble's movement path. This includes, but is not limited to, a spatially offset arrangement where the water inlet and the end of the heating tube are spatially opposite, a physical barrier arrangement with a baffle between the water inlet and the heating tube, and other structural forms that can deviate the water inlet from the bubble's movement path. In other words, "barrier structure" encompasses both implementation methods that achieve bubble isolation by adding independent components and implementation methods that achieve bubble avoidance by utilizing the spatial layout of the components themselves.

[0006] A preferred embodiment of the present invention is that the heating assembly further includes a water intake section, the water intake section is provided with a water inlet, the heating tube is located on one side of the water intake section, and the water inlet is located on the opposite side away from the heating tube.

[0007] The preferred technical solution of the present invention is that the minimum distance d2 between the water intake part and the heating pipe is 15mm≥d2≥4mm.

[0008] A preferred embodiment of the present invention is that a control valve is further provided in the downstream pipeline of the flow detection component. The control valve is located between the flow detection component and the three-way structure, and the inner diameter of the pipeline from the outlet of the control valve to the extraction chamber is smaller than the inner diameter of the pipeline before the inlet of the control valve.

[0009] A preferred embodiment of the present invention is that the flow detection component is arranged adjacent to the control valve, and the pipe length between the outlet of the flow detection component and the inlet of the control valve is ≤5cm.

[0010] A preferred embodiment of the present invention is that the pipeline between the outlet of the control valve and the inlet of the extraction chamber has a gradient change in diameter, with the end diameter being smaller than the front diameter.

[0011] A preferred embodiment of the present invention is that the flow detection component is provided with a quick-release connection structure.

[0012] A preferred embodiment of the present invention is that the flow detection component is a high-temperature resistant flow meter.

[0013] A preferred embodiment of the present invention is that the heating tube extends upward in a stepped structure.

[0014] The present invention provides a coffee machine, including the piping system for a coffee machine described above.

[0015] The beneficial effects of this invention are: This invention addresses the technical problem of inaccurate flow and pressure detection in the extraction chamber of a pressure swing extraction (PSA) pipeline system by systematically reconstructing the water circuit's physical structure. The solution comprises three core structures: a barrier structure is installed between the water inlet and the bubble-generating area of ​​the heating element, causing the water inlet to deviate from the bubble's movement path, making it difficult for bubbles to enter the inlet; the flow detection component is located after the heating element, with the water flow direction in its section essentially consistent with the actual flow direction towards the extraction chamber, effectively eliminating the situation where a reverse pressure difference forms on both sides of the flow detection component, driving water to flow backward through it; and the pressure detection component is connected to a position adjacent to the extraction chamber via a three-way bypass, ensuring that the detected value accurately reflects the actual pressure at the extraction chamber inlet. These three core structures control the deviation between the detected flow rate and the actual flow rate, as well as the deviation between the detected pressure value and the actual pressure in the extraction chamber, within predetermined ranges. This provides a reliable detection basis for the precise control of the PSA system, ultimately ensuring the consistency of coffee liquid output accuracy and extraction quality. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a three-dimensional diagram of the piping system for a coffee machine according to Embodiment 1 of the present invention. Figure 1 ; Figure 2 This is a three-dimensional diagram of the piping system for a coffee machine according to Embodiment 1 of the present invention. Figure 2 ; Figure 3 This is a partial exploded view of the piping system for a coffee machine according to Embodiment 1 of the present invention; Figure 4 This is a partial three-dimensional view of the piping system for a coffee machine according to Embodiment 1 of the present invention. Figure 1 ; Figure 5 A partial spatial arrangement diagram of the piping system for a coffee machine according to Embodiment 1 of the present invention; Figure 6 This is a partial three-dimensional view of the piping system for a coffee machine according to Embodiment 1 of the present invention. Figure 2 ; Figure 7 This is a perspective view of the three-way structure of Embodiment 1 of the present invention; Figure 8 This is a perspective view of the heating tube according to Embodiment 1 of the present invention.

[0018] In the picture: 1-Heating component; 11-Heating tube; 12-Water inlet; 13-Water intake section; 14-Opening; 2-Flow detection component; 21-First inlet; 22-First outlet; 3-Pressure detection component; 4-T-way structure; 41-First port; 42-Second port; 43-Third port; 44-Reverse extension section; 5-Control valve; 51-Second inlet; 52-Second outlet; 6-Extraction chamber; 7-Fixing component; 71-Snap-fit ​​part. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 This embodiment provides a coffee machine, such as Figure 1-8 As shown. For ease of explanation, only the key structural components of the technical solution of this invention are shown in the coffee machine illustration, while the pipe and electrical wiring structures are omitted. The coffee machine of this embodiment includes a piping system for the coffee machine. Specifically, the pipeline system includes a heating component 1, which has a heating tube 11 and a water inlet 12 inside. The water inlet 12 is located at the end of the heating tube 11 and is used to draw out the water heated by the heating tube 11. A flow detection component 2 is located downstream of the water inlet 12 and is used to detect the amount of water flowing through the water path. A pressure detection component 3 is connected to the pipeline between the downstream of the flow detection component 2 and the extraction chamber 6 through a three-way structure 4. The first port 41 of the three-way structure 4 is connected to the downstream pipeline of the flow detection component 2, the second port 42 of the three-way structure 4 is connected to the inlet of the extraction chamber 6, and the third port 43 of the three-way structure 4 is connected to the pressure detection component 3. A barrier structure is provided between the water inlet 12 and the bubble generation area of ​​the heating tube 11. The barrier structure is located on the path of the bubble moving from the bubble generation area to the water inlet 12 so that the water inlet 12 avoids the passage path of the bubble in the heating tube 11. In the variable pressure extraction coffee machine of this embodiment, the water pump is a DC rotary vane pump. As is the conventional setup on the market, the water pump is located upstream of the heating component 1, and the flow rate of the pumped water can be adjusted by adjusting the vane speed.

[0021] Existing products exhibit significant and unstable discrepancies between the detected flow rate and the actual flow rate, and there is also a noticeable deviation between the detected pressure value and the actual pressure in the extraction chamber. This embodiment addresses the sources of these discrepancies by focusing on both flow rate and pressure detection.

[0022] During the extraction process, the flow rate and pressure of the water pump fluctuate. This flow rate fluctuation manifests as periodic fluctuations in the water flow. If the flow detection component is located in the water path between the pump and the heating element (as in commercially available products), the following problems arise: Flow detection components (such as Hall effect impeller flow meters) operate based on Bernoulli's principle, and their internal structure dictates that they lack directional recognition capabilities—regardless of whether the water flows forward or backward, the flow detection component accumulates the forward flow rate. Specifically, the flow detection component is prone to the following situations affecting the measurement of the water output from the extraction chamber: 1. Reverse measurement; 2. Due to the pressure difference in the pipeline, even if water flows into the extraction chamber, measurement stops because the pressure on both sides of the flow detection component is the same; 3. Forward measurement, but the water passing through the flow meter is not equal to the water flowing into the extraction chamber. The pressure swing extraction system is subject to various pressure variations, such as continuous changes in the pump's operating status and significant increases in water temperature within the heating channel. These factors cause dynamic pressure changes in multiple areas of the pipeline system, resulting in pressure signals on both sides of the flow meter that are independent of the amount of water flowing into the extraction chamber. These signals accumulate to form a significant systematic deviation, making it difficult for the flow rate detection value to accurately reflect the instantaneous inflow rate into the extraction chamber, and also difficult to eliminate using algorithms. Simultaneously, when the heating tube dynamically heats the water, dissolved gases in the water precipitate and accumulate into bubbles due to the increased temperature. These bubbles rise along the inner wall of the heating tube, accumulate at local high points at the water inlet, and enter the downstream water path, further increasing the deviation between the detected value and the actual water volume. The heat generated by the heating tube also causes fluctuations in the pressure of nearby pipelines. To address this, the technical solution of this embodiment constructs a three-level isolation structure in the water path to solve the aforementioned fluctuation deviation problem.

[0023] The first-level isolation structure acts on the bubble interference source. Bubbles inside the heating tube rise vertically driven by buoyancy. An obstruction structure is installed along their path from the bubble-generating area to the water intake, physically altering the bubble's movement boundary. It should be noted that the "obstruction structure" does not refer to a specific fixed component, but rather to a general arrangement of structures placed between the water intake and the bubble-generating area of ​​the heating tube, capable of blocking or guiding bubbles away from the water intake direction. This can be achieved through various means, including but not limited to staggered arrangements of the water intake and the bubble-generating area, the water intake being located away from the heating tube, and baffles added along the bubble's rising path. Through this obstruction structure, bubbles are confined to the vicinity of the inner wall of the heating tube or to local high points, while water, due to its higher density and continuous flow within the heating tube, enters the downstream pipeline through the water intake. Consequently, the bubble content in the water entering the downstream pipeline is significantly reduced, the medium in the water section where the flow detection component is located tends to be a single-phase liquid, and the random fluctuations in the detection signal caused by the gas-liquid two-phase flow are eliminated.

[0024] The second-stage isolation structure targets pressure fluctuations in the piping system. The flow detection component is positioned downstream of the water intake, after the heating element, rather than in the water path between the pump and the heating element. The water flow direction in the section containing the flow detection component is essentially the same as the actual flow direction into the extraction chamber, avoiding the factors that could affect the flow detection component's readings. Furthermore, being downstream of the heating element and closer to the extraction chamber, the flow detection component has a more direct correlation with the actual amount of water entering the extraction chamber, unaffected by complex pressure changes within the piping system. This structure effectively reduces the deviation between the detected flow rate and the actual amount of water entering the extraction chamber.

[0025] The third-level isolation structure ensures the accuracy of feedback from the pressure detection end. The pressure detection component is not connected in series in the main water path; instead, it is connected via a T-junction as a bypass to the pipeline downstream of the flow detection component and the extraction chamber, with the bypass closer to the extraction chamber. The first port of this T-junction connects to the downstream pipeline of the flow detection component to introduce water flow, the second port directs the water flow to the inlet of the extraction chamber, and the third port connects to the pressure detection component to sense the water pressure at that point. Because the third port of the T-junction is a bypass connection to the main water path, there is no continuous water flow through the branch where the pressure detection component is located. Therefore, the pressure value it detects is not affected by friction loss during flow and can reflect the actual water pressure at the extraction chamber inlet. This actual water pressure value is input as a feedback signal to the control unit of the variable pressure system. The control unit then adjusts the operating parameters of the water pump accordingly, making the water pressure at the extraction chamber inlet approach the target extraction pressure, thereby establishing a definite correspondence between the change in the pump's output flow rate and the actual amount of water entering the extraction chamber.

[0026] This embodiment eliminates the corresponding sources of deviation from both flow rate and pressure detection perspectives. The barrier structure eliminates the interference of air bubbles on flow rate detection; the downstream placement of the flow rate detection component reduces the impact of pressure fluctuations on the detected value; and the bypass connection of the pressure detection component eliminates the impact of frictional resistance on pressure detection. These three features work together to control the deviations between the detected flow rate and the actual flow rate, as well as the deviations between the detected pressure and the actual pressure, within predetermined ranges, thus providing a reliable detection basis for the precise control of the pressure swing extraction system.

[0027] Specifically, the heating assembly 1 includes a water intake section 13, with a water inlet 12 disposed on the water intake section 13 and offset towards the bottom side of the water intake section 13. The obstruction structure is that the water inlet 12 and the bubble-generating area of ​​the heating tube 11 are spatially misaligned, with the heating tube 11 located on one side of the water intake section 13 and the water inlet 12 located on the opposite side away from the heating tube 11. In the end region of the heating tube, bubbles are driven by buoyancy to climb up the inner wall of the heating tube towards the top of the tube cavity, and their movement trajectory is mainly concentrated in the area above the periphery of the heating tube. If the water inlet is located on the same side as the heating tube, the movement trajectory of the water inlet and the bubbles are in the same spatial domain. Even if there is a height difference between the water inlet and the bubble-generating area of ​​the heating tube in terms of vertical height, some bubbles may still enter the water inlet due to the lateral migration caused by the drag force of the water flow during the rising process. By positioning the water inlet on the opposite side from the heating pipe, the space between the inlet and the heating pipe is separated by the water intake unit. Air bubbles rising near the inner wall of the heating pipe must cross the structural wall of the water intake unit to reach the inlet. Since the water inlet faces the heating pipe, the wall of the water intake unit physically acts as a barrier to the lateral migration of the air bubbles as the water flows from the heating pipe to the inlet. Through this spatial arrangement, the separation of air bubbles and water along their spatial paths is achieved using the structural wall of the water intake unit itself, without the need for additional components. This simplifies the implementation of the barrier structure and reduces manufacturing costs and assembly complexity.

[0028] like Figure 5As shown, preferably, the horizontal height of the water intake section 13 is higher than the horizontal height of the heating pipe 11, but not exceeding 15mm. In this embodiment, d1 = 14mm. Here, the horizontal height of the water intake section 13 is the horizontal height of the lowest point of the water intake section, and the horizontal height of the heating pipe 11 is the horizontal height of the highest point of the heating pipe. The relative position of the water intake section and the heating pipe in the vertical direction is an important spatial dimension affecting the blocking structure's effect on bubble interception. At this vertical height, the bubbles have undergone a long upward journey driven by buoyancy after being generated by the heating pipe, during which most of the bubbles have gradually aggregated and broken during the ascent, and the bubble content is significantly lower than in the area near the heating pipe. Through experiments, limiting the height difference between the water intake and the heating pipe to no more than 15mm is based on considerations of the liquid surface position in the heating chamber. The water intake needs to be higher than the heating pipe to avoid the bubble-rich area near the heating pipe; however, if the height difference between the water intake and the heating pipe is too large, the water intake will be too close to the liquid surface in the heating chamber. The liquid surface is the area where bubbles ultimately accumulate, forming a bubble aggregation layer that persists near the surface until the bubbles completely burst. When the water inlet is too close to the liquid surface, its suction flow field will reach this bubble aggregation layer, causing unbroken bubbles to be directly drawn into the inlet. Limiting the height difference to no more than 15mm ensures that the water inlet is positioned above the heating pipe to avoid the bubble-rich area near it, while maintaining sufficient distance from the liquid surface to prevent the suction from interfering with the bubble aggregation layer at the liquid surface, thus ensuring that no bubbles are mixed into the water flowing out of the inlet. Within this height difference range, the liquid layer area where the inlet is located maintains sufficient vertical separation from the end of the bubble's rising path, further enhancing the vertical spatial separation effect of the barrier structure.

[0029] like Figure 5As shown, preferably, the minimum distance d2 between the water intake section 13 and the heating tube 11 satisfies 15mm ≥ d2 ≥ 4mm. In this embodiment, d2 = 4.2mm. Through testing, it was found that if the minimum distance between the water intake section and the heating tube is less than 4mm, the gap between the wall of the water intake section and the outer wall of the heating tube is too narrow. The suction effect of the water intake will create a non-negligible negative pressure gradient within this gap. When the bubbles rise to the height of the water intake section, they are easily laterally shifted due to this negative pressure gradient, thus crossing the boundary of the water intake section wall and entering the water intake side. On the other hand, if the minimum distance is greater than 15mm, the horizontal position of the water intake section relative to the heating tube is too far off, resulting in an increase in the overall horizontal size of the heating assembly. This is not conducive to the compact arrangement of other components within the limited space inside the coffee machine. Importantly, an excessively large minimum distance will cause the water temperature drawn from the water intake to be lower than the water temperature in the vicinity of the heating tube. Since the coffee extraction process has specific requirements for water temperature, a drop in water temperature will directly affect the extraction efficiency of flavor substances in the coffee powder, thereby affecting the quality of the final coffee liquid. The minimum distance between the water intake section and the heating tube is limited to 4mm to 15mm. Within this range, the gap between the wall of the water intake section and the heating tube is neither too narrow, which would interfere with the normal rising path of the bubbles due to the suction flow field at the water intake, nor too wide, which would cause unnecessary space occupation and temperature deviation between the water temperature at the water intake and the heating tube. This achieves a balance between the structural layout of the barrier structure and the extraction temperature.

[0030] Preferably, a control valve 5 is also provided in the downstream pipeline of the flow detection component 2. The control valve 5 is located between the flow detection component 2 and the three-way structure 4, and the inner diameter of the pipeline from the outlet of the control valve 5 to the extraction chamber 6 is smaller than the inner diameter of the pipeline before the inlet of the control valve 5. The reason for this preferred solution is as follows: the control valve is located between the flow detection component and the three-way structure to control the on / off state of the downstream water path. After the coffee machine completes a single extraction, the control valve switches to the closed state, at which time residual water remains in the pipeline section between the outlet of the control valve and the extraction chamber. In the pressure swing extraction system, the water pump needs to re-establish the extraction pressure at the start of extraction. If the inner diameter of this pipeline section is the same as the inner diameter of the upstream pipeline, the water pump needs to compress the water in this pipeline section to the target pressure after starting. The time required for this process depends on the ratio of the pipeline volume to the water pump output flow rate. By setting the inner diameter of the pipe from the control valve outlet to the extraction chamber to be smaller than the inner diameter of the pipe before the control valve inlet, the volume per unit length of this pipe section is reduced. Under the same pipe length conditions, the time required for the water pump to compress the water in this pipe section to the target pressure after starting is shortened. At the same time, the pipe diameter contraction increases the flow velocity of the water when passing through the contraction section. According to the fluid continuity equation (under constant flow conditions, the flow velocity is inversely proportional to the square of the pipe diameter), the increased flow velocity after the pipe diameter reduction gives the water greater kinetic energy when flowing out of the extraction chamber inlet, which is beneficial for the water to quickly diffuse into the water distribution area after entering the extraction chamber.

[0031] Preferably, the flow detection component 2 is arranged adjacent to the control valve 5, and the pipe length between the outlet of the flow detection component 2 and the inlet of the control valve 5 is ≤5cm. In the pressure swing extraction system, the opening and closing action of the control valve changes the on / off state of the water circuit through the movement of the valve core. During the movement of the valve core, a pressure transient is generated in the water circuit, which propagates upstream and downstream along the pipe in the form of a water hammer wave. If the pipe length between the outlet of the flow detection component and the inlet of the control valve is long, a large volume of dead water will remain in this section of the pipe. Dead water refers to water with a flow velocity close to zero near the pipe wall when the water circuit is in continuous flow. The existence of the dead water zone means that the flow change detected by the flow detection component cannot truly reflect the flow change trend entering the extraction chamber in the initial stage of the control valve opening, because a portion of the water volume fills the dead water zone before being pushed. When the pipe length between the two is ≤5cm, the spatial interval between the flow detection component and the control valve is minimized. The volume of stagnant water in this section of pipe is confined to the small space enclosed by the connection port of the flow detection component and the control valve. This ensures a high degree of synchronicity between the flow change at the location of the flow detection component and the flow change at the outlet of the control valve after the control valve is opened. Furthermore, the compact connection shortens the transmission time of water flow from the flow detection component to the control valve, making the flow detection signal and the actual water flow status more synchronous on the time axis, thus improving the timeliness of the detection data. In this embodiment, the pipe length between the outlet of the flow detection component 2 and the inlet of the control valve 5 is approximately 46mm.

[0032] like Figure 6As shown, preferably, the control valve 5 is located downstream of the flow detection component 2. Specifically, the water flow sequence is as follows: water inlet 12 → inlet of flow detection component 2 (first inlet 21) → outlet of flow detection component 2 (first outlet 22) → inlet of control valve 5 (second inlet 51) → outlet of control valve 5 (second outlet 52). In this layout, the on / off action of the control valve directly controls whether the water flow downstream of the flow detection component can continue to advance to the extraction chamber. Therefore, the water volume detected by the flow detection component is measured before the water flow passes through the control valve. Since the control valve is located downstream of the flow detection component, there are no other branch structures between the detection point of the flow detection component and the cut-off point of the control valve that can introduce or draw water into or out of the water path. Thus, all the water volume detected by the flow detection component can flow to the extraction chamber through the control valve when the control valve is open. If the control valve is positioned upstream of the flow detection component, its on / off action directly alters the water flow at the inlet of the flow detection component. When the control valve is closed, the water flow at the flow detection component stops. However, water that has passed through the control valve but not yet entered the extraction chamber may still remain in the pipeline downstream of the control valve. This portion of water cannot be recorded by the flow detection component, resulting in the flow detection value not fully reflecting the total amount of water actually entering the extraction chamber. In contrast, by positioning the control valve downstream of the flow detection component, the component can detect the total amount of water about to enter the control valve. This detected value corresponds to the amount of water flowing through the control valve into the extraction chamber when the control valve is open, and to the amount of water stopped by the control valve when it is closed. There is a one-to-one correspondence between the amount of water detected by the flow detection component and the actual amount of water entering the extraction chamber through the control valve. Furthermore, during extraction, coffee grounds are impacted by high-pressure water flow within the extraction chamber. Grounds may detach from the coffee puck surface and remain suspended in the water within the extraction chamber due to the impact of the water flow or pressure fluctuations. During the depressurization phase after the control valve closes or the pre-pressurization phase before the next extraction begins, a pressure difference may exist between the extraction chamber and the upstream pipeline. This pressure difference drives the water in the extraction chamber to flow upstream in a counter-current direction. If the control valve is located upstream of the flow detection component, the water in the extraction chamber flows backward through the control valve and intermediate pipeline before reaching the flow detection component. The powder and sludge carried in the water then enter the flow detection component. These particles deposit or adhere to the surface of the detection element within the flow channel, reducing the cross-sectional area of ​​the flow channel or hindering the movement of the detection element, thus reducing the detection performance of the flow detection component. By placing the control valve downstream of the flow detection component, it is positioned between the flow detection component and the extraction chamber, physically separating them. When the control valve is closed, its internal shut-off element forms a sealed interface that blocks the water flow path. The powder and sludge are blocked by this sealed interface in the counter-current direction and cannot cross the control valve to enter the upstream pipeline section where the flow detection component is located.Based on the above water circuit logic, this technical solution limits the relative positional relationship between the flow detection component and the control valve, ensuring that the detection behavior of the flow detection component occurs before the cut-off action of the control valve. This avoids the situation where undetected water volume enters the extraction chamber through the control valve due to the presence of a detection point upstream of the control valve. Structurally, this ensures the correspondence between the flow detection value and the actual output volume. At the same time, the cut-off function of the control valve blocks the upstream backflow path of the powder and slag, reducing the possibility of powder and slag entering the flow detection component. Structurally, this extends the effective working cycle of the flow detection component.

[0033] Preferably, the flow detection component 2 and the control valve 5 are respectively fixedly connected to the housing of the heating component 1. Both the flow detection component and the control valve are functional components with a certain mass and volume. During water circuit operation, water flows through both, and the pulsation and pressure changes of the water flow will exert a force on the installation stability of the components. By fixing the flow detection component and the control valve to the housing of the heating component, the housing wall of the flow detection component and the housing wall of the control valve each form a direct mechanical connection with the housing of the heating component. This connection can be a detachable fixing method such as bolt connection, snap connection, or screw connection, or a non-detachable fixing method such as welding. Their common feature is that the spatial position of the flow detection component and the control valve relative to the housing of the heating component is fixed. Through this fixed connection method, the flow detection component and the control valve each obtain independent installation support, and their installation processes do not interfere with each other. After installation, their relative positions are maintained by the heating component housing as a common installation reference. When the pipeline between the flow detection component and the control valve expands and contracts due to water flow impact or temperature changes, both are fixed to the same heating component housing. The housing has high rigidity and a coefficient of thermal expansion similar to that of the pipeline material, which limits the relative displacement between the two ends of the pipeline. This keeps the tensile or compressive stress on the pipeline along its length within a small range, reducing the risk of leakage due to stress concentration at pipeline joints. Simultaneously, since both are fixedly connected to the heating component housing, the flow detection component and the control valve can be independently installed and removed from the heating component housing. When one component needs maintenance or replacement, it is not necessary to disassemble the fixed connection structure of the other component. Furthermore, using the heating component housing as a common mounting carrier, the spatial positions of the flow detection component and the control valve are predetermined by the structural layout of the housing. Their installation positions have good repeatability and consistency, eliminating the need to adjust their relative positions individually during mass production, thus simplifying the assembly process. This fixed connection method also provides structural constraints on maintaining the pipe length between the flow detection component and the control valve. When both are fixed to the housing, the pipe endpoint positions are fixed by the housing structure, eliminating the possibility of changes in the endpoint spacing due to pipe suspension or external force pulling. The pipe length remains stable throughout the coffee machine's entire lifespan. In this embodiment, a threaded connection is used for fixing.

[0034] Preferably, the outlet of the flow detection component 2 is connected to the housing of the heating component and then to the inlet of the control valve 5. The outlet of the flow detection component is where water flows out of the flow detection component, and the inlet of the control valve is where water flows into the control valve. By connecting the outlet of the flow detection component to the housing of the heating component and then to the inlet of the control valve, the water flowing out of the flow detection component does not directly enter the control valve from the external pipeline, but instead returns to the housing of the heating component via a connecting path, and then flows out from the housing and into the control valve. In this connection method, at least a portion of the pipeline between the flow detection component and the control valve is located inside the housing of the heating component. The housing of the heating component has a high temperature during the operation of the coffee machine, and this temperature is transferred to the pipeline located inside the housing through the housing wall. When the external connecting pipeline between the flow detection component and the control valve is used under low ambient temperature conditions, the pipe wall temperature may be lower than the temperature of the water flowing through the pipeline, and the water temperature may decrease when flowing through this section of the pipeline due to heat dissipation from the pipe wall. By connecting the outlet of the flow detection component to the housing and then to the inlet of the control valve, a portion of the piping between the flow detection component and the control valve is housed within the housing of the heating element. This section of piping is heated by the heat from the heating element within the housing, and its wall temperature is close to the temperature of the water inside the housing. When water flows out of the flow detection component and into the piping section within the housing, the pipe wall transfers heat to the water, maintaining its temperature level as it flows through this section and preventing a drop in water temperature due to a low external environment. This connection method also provides spatial support and protection for the piping between the flow detection component and the control valve within the heating element housing. The piping inside the housing is enclosed by the housing structure, reducing the risk of deformation or damage to the piping due to external impacts or pulling. Meanwhile, this connection path allows the pipe section between the outlet of the flow detection component and the inlet of the control valve to form at least a portion of a shared thermal environment inside the heating component housing. When water flows in this section, its temperature change is mitigated by the thermal inertia of the heating component, which helps to reduce the potential impact of water density changes caused by temperature fluctuations on subsequent flow detection.

[0035] Preferably, the pipeline between the outlet of control valve 5 and the inlet of extraction chamber 6 exhibits a diameter gradient, with the diameter at the end being smaller than that at the beginning. Within this pipe section, the water flow continuously accelerates along the flow direction, and the accelerating flow field exerts additional inertial force on the air bubbles entrained in the water flow. Since the density of air bubbles is much lower than that of water, during the accelerated flow, the inertial response time of the air bubbles (i.e., the time required for the bubble velocity to follow the change in fluid velocity) is longer than the inertial response time of the surrounding water. Therefore, the air bubbles have a lagging velocity response relative to the water in the accelerating flow field. This lag effect causes the air bubbles to be subjected to a pressure gradient pointing towards the pipe axis in the radial direction, pushing the air bubbles towards the axial region of the pipeline. In the axial region of the pipeline, the water flow velocity is the highest and the turbulence intensity is the strongest. The air bubbles in this region are subjected to continuous shearing and stretching, further promoting the breakup and dissolution of the air bubbles. Meanwhile, due to the reduced end pipe diameter, the pipe wall area corresponding to a unit volume of water flow increases, and the frictional shear force between the water flow and the pipe wall increases. This shear force has a peeling effect on bubbles near the pipe wall, preventing bubbles from forming an air film layer or bubble aggregation zone near the pipe wall, thereby ensuring that the bubbles in the water flow entering the extraction chamber are controlled at a low level. In this embodiment, the pipe between the outlet of control valve 5 and the inlet of extraction chamber 6 has a front end diameter of 3 mm and a rear end diameter of 1.5 mm and a rear end length of 134 mm.

[0036] Preferably, the flow detection component 2 is detachably installed in the water circuit, and the flow detection component 2 is equipped with a quick-release connection structure. The flow detection component is a functional component that is easily affected by the working environment during the use of the coffee machine. In the operating mode of the pressure swing extraction system, the flow detection component is constantly in a dynamic water flow environment, and its internal sensing elements (such as impellers, Hall elements, or ultrasonic transducers) may experience detection deviations under the combined effects of water flow impact and scale deposition. In the overall structure of the coffee machine, the flow detection component is usually arranged in a narrow space between the heating element and the extraction chamber, and is connected to upstream and downstream components on both sides via pipes. In this embodiment, specifically, the flow detection component 2 is provided with a columnar first inlet 21 and a first outlet 22. The housing of the heating component 1 is provided with two corresponding openings 14 for fixing the first inlet 21 and the first outlet 22 and for water circuit connection. After the flow detection component 2 is inserted into the housing of the heating component 1, the fixing member 7 is then inserted. The fixing member 7 is provided with two snap-fit ​​parts 71 that match the first inlet 21 and the first outlet 22. The first inlet 21 and the first outlet 22 are respectively provided with limiting groove structures that match the snap-fit ​​parts 71 to prevent the flow detection component 2 from loosening after the fixing member 7 is snapped in. Finally, the fixing member 7 is fixed to the housing of the heating component 1 with screws to complete the entire installation. This solution reduces the technical threshold and operation time of after-sales maintenance, enabling the flow detection component to achieve quick installation and disassembly.

[0037] Preferably, the first port 41 and the second port 42 are connected in a first L-shaped structure. The tee structure 4 is provided with a reverse extension section 44 in the opposite direction to the second port 42. The second port 42 is connected to the third port 43 in a second L-shaped structure via the reverse extension section 44. The first L-shaped structure here refers to the spatial connection where the axial direction of the first port and the axial direction of the second port form an angle, and the internal channel between them has a bend. The reverse extension section is a pipe segment structure that extends in the opposite direction to the axial direction of the second port. The second L-shaped structure refers to the structure where the water flow at the second port turns after passing through the reverse extension section and connects to the third port. This channel has another bend. Through the setting of this reverse extension section, the water flow enters from the first port, flows partly to the reverse extension section after passing through the bend of the first L-shaped structure, then flows to the bend of the second L-shaped structure, and finally reaches the direction of the third port. Compared to the traditional T-shaped three-way structure, the reverse extension section extends in the opposite direction to the water flow from the first port to the outlet of the second port. This reduces the positive impact of the water flow in the main channel on the end face of the detection end, avoids the direct impact of the water flow on the end face of the detection end, reduces the flow around the detection end and local pressure fluctuations, and makes the pressure value detected by the pressure detection component closer to the state during water extraction.

[0038] Preferably, the length of the reverse extension section 44 is 5-10 mm. With a longer reverse extension section, the positive impact of the water flow in the main channel on the end face of the detection end is reduced, the dynamic pressure component on the end face of the detection end is reduced, the flow around the detection end is weakened, and the degree of local pressure field distortion caused by the flow around the detection end is reduced. This reduces the dynamic pressure interference component in the pressure value detected by the pressure detection component, and the detected value is closer to the water pressure during extraction, thus meeting the requirement for accurate pressure detection during the extraction process. However, a longer reverse extension section is not always more advantageous—as the length of the reverse extension section continues to increase, the third port gradually shifts away from the extraction chamber inlet in space, the pipeline path between the pressure tap and the extraction chamber inlet lengthens accordingly, and the increased friction loss reduces the consistency between the water pressure at the pressure tap and the actual pressure at the extraction chamber inlet. Therefore, the length of the reverse extension section needs to ensure improved stability of the detection end while keeping the deviation between the pressure tap and the extraction chamber inlet within a suitable range. After testing, limiting the length of the reverse extension segment to 5mm to 10mm can meet the above test requirements. Specifically, in this embodiment, the length of the reverse extension segment 44 is selected as 7mm.

[0039] The internal channel diameter of the T-junction determines the cross-sectional area of ​​water flow from the upstream section of the main water path to the extraction chamber. If the diameter is too large, the water velocity within the T-junction decreases, and the pressure transmission response between the water at the pressure tap where the pressure detection component is located and the main channel slows down. If the diameter is too small, the water flow is excessively throttled through the T-junction, resulting in significant local resistance loss. This loss causes the water pressure at the outlet of the T-junction to be lower than the water pressure at the inlet, affecting the actual pressure value at the inlet of the extraction chamber. Preferably, the diameter within the T-junction 4 is 1.5-2.0 mm. As a further preferred embodiment, this solution limits the diameter within the T-junction to 1.5 mm to 2.0 mm. This diameter range provides an appropriate cross-sectional area for water flow in the coffee machine's extraction water path. Within this diameter range, the water velocity is moderate when passing through the T-junction, and the frictional resistance loss caused by the water flow and the inner wall of the T-junction is small. Meanwhile, the 1.5mm to 2.0mm diameter matches the resistance characteristics of the coffee puck at the inlet of the coffee machine's extraction chamber—the water flow within this diameter range is appropriately accelerated before entering the extraction chamber, which facilitates the rapid diffusion of the water flow to the water distribution area after entering the extraction chamber, promoting uniform wetting of the coffee puck. Furthermore, with a diameter of 1.5mm to 2.0mm, the pressure transmission between the water at the tap and the main channel has a shorter response time. When changes in the water pump's operating parameters cause changes in the water pressure, the pressure at the tap can promptly follow the pressure changes in the main channel. In this embodiment, the diameter within the three-way structure 4 is 1.5mm.

[0040] Preferably, the T-junction 4 is disposed within the housing of the heating assembly 1. In the water circuit structure, the T-junction is located on the main body of the water circuit near the inlet of the extraction chamber, and its physical installation position determines the actual path length of the hot water pipeline from the outlet of the control valve to the inlet of the extraction chamber. If the T-junction is installed outside the housing of the heating assembly, the hot water drawn from the water inlet of the heating assembly must first flow through the pipeline to the control valve, then through the pipeline to the T-junction, and finally through the pipeline into the extraction chamber. Under this arrangement, the hot water travels a long pipeline path after exiting the heating assembly, and heat is lost to the surrounding environment along the outer wall of the pipeline, resulting in a drop in water temperature. As a further preferred embodiment of the above solution, this solution disposes of the T-junction within the housing of the heating assembly. The housing of the heating assembly surrounds the heating tube, and the interior of the housing maintains a relatively high ambient temperature during the operation of the coffee machine, which is close to the water temperature after being heated by the heating tube. The T-junction being disposed within the housing means that the T-junction is in the same temperature field as the heating tube, and the hot water flowing through the T-junction is insulated by the high temperature environment inside the housing, reducing its heat loss to the surrounding environment. Meanwhile, by placing the three-way structure inside the heating component housing, the pipeline path from the control valve outlet to the three-way structure is limited to inside the heating component housing. This section of pipeline does not need to pass through the heating component housing and then turn back to pass through, which shortens the actual length of the hot water pipeline, reduces heat loss along the pipeline, and maintains the stability of the water temperature entering the extraction chamber.

[0041] Preferably, the flow detection component 2 is a high-temperature resistant flow meter. The high-temperature resistant flow meter is made of materials that can maintain stable material properties and structural dimensions within the operating temperature range of the coffee machine. Its magnetic components do not experience magnetic flux attenuation at high temperatures, and the impeller and housing do not deform at high temperatures. Thus, it maintains consistent detection performance and structural stability during long-term use, extending the effective service life of the flow detection component.

[0042] Preferably, the heating tube 11 extends in an upward stepped structure. This upward stepped extension of the heating tube 11 is primarily to meet the assembly requirements of the heating tube within the limited internal space of the coffee machine. The heating tube needs to avoid other components through stepped bends, while simultaneously adapting its extension path to the shape of the inner cavity of the pot. Furthermore, the upper end of the heating tube 11 extends along the stepped path to a position near the water inlet 12, allowing the heating section of the heating tube 11 to cover the area near the water inlet, thus fully heating the water in front of the inlet and achieving uniform heating of the water inside the entire pot. Simultaneously, the end of the upper end of the heating tube 11 is spatially close to the water inlet 12, but spatially opposite to it—that is, the water inlet 12 is located on the side of the water inlet section 13 away from the heating tube 11. Although the end of the upper end of the heating tube 11 extends to the vicinity of the water inlet, its extension direction is deviated from the orientation of the water inlet. In this spatial layout, the heating tube 11 fully heats the water in the front area of ​​the water inlet, ensuring the uniformity of the water temperature taken from the inlet. Simultaneously, because the water inlet and the end of the heating tube are spatially opposite, the rising paths of bubbles generated in the end area of ​​the heating tube 11 during heating are spatially offset from the water inlet area, making it difficult for bubbles to enter the inlet. Therefore, the upward stepped extension structure of the heating tube 11 meets the functional requirements of assembly and uniform heating, while also structurally cooperating with the opposite layout of the water inlet, achieving effective separation of bubbles and water flow without adding additional components. Furthermore, the heating tube 11 includes a first heating tube 111 and a second heating tube 112 arranged vertically, with the first heating tube 111 extending upwards in a stepped structure and the second heating tube 112 extending downwards in a stepped structure. By further dividing the heating tube into the vertically arranged first and second heating tubes, a more refined heating tube arrangement scheme is achieved. In this design, the two-tiered heating tubes increase the total heating area, allowing the water to stay in the heating chamber for a longer period, resulting in more thorough heating. In terms of space utilization, the vertical arrangement fully utilizes the vertical space of the heating chamber, reducing horizontal space occupation and facilitating the miniaturization of the heating components.

[0043] Example 2 The difference between this embodiment and Embodiment 1 lies in the specific implementation of the barrier structure. In this embodiment, the barrier structure is a baffle disposed between the water inlet and the bubble-generating area of ​​the heating tube. The baffle is located on the path of the bubbles moving from the bubble-generating area to the water inlet, and is used to prevent the bubbles from rising vertically to the location of the water inlet 12. The baffle is disposed inside the heating assembly, specifically between the end area of ​​the heating tube and the water inlet. The baffle can be made of metal sheet and integrally formed with the heating tube or fixed to the inner wall of the heating assembly by welding, snap-fitting, or other methods. The baffle can extend horizontally or obliquely, guiding the bubbles away from the water inlet, and the width of the baffle can cover the entire lateral range through which the bubbles may pass. As an independent physical barrier component, this baffle, like the spatially opposed layout in Embodiment 1, belongs to the category of "barrier structure." Both use different structural means to achieve the same function—to deviate the water inlet from the movement path of the bubbles, thus making it difficult for the bubbles to enter the water inlet. In actual product design, depending on the internal spatial layout and assembly conditions of the heating component, spatial separation, adding baffles, or a combination of both can be selected to achieve spatial isolation between the air bubble and the water inlet.

[0044] Comparative Example 1 This comparative example provides a piping system for a coffee machine, the structure of which is basically the same as that of Embodiment 1, the only difference being that: no obstruction structure is provided, that is, the water inlet and the end of the heating tube are not spatially misaligned, and no physical obstruction components such as baffles are provided.

[0045] Comparative Example 2 This comparative example provides a piping system for a coffee machine, the structure of which is basically the same as that of Embodiment 1, except that the flow detection component is located in the water line between the water pump and the heating component.

[0046] Comparative Example 3 This comparative example provides a piping system for a coffee machine, the structure of which is basically the same as that of Embodiment 1, except that the pressure detection component is directly connected in series in the main water circuit between the flow detection component and the control valve.

[0047] Test methods (a) Flow detection accuracy test A standard flow meter is installed in series in the downstream pipeline of the flow detection component under test, without any buffer or damping device between them. The coffee machine is started and operates according to the preset pressure curve. The data acquisition system simultaneously records the output signal of the flow detection component under test and the output signal of the standard flow meter. In each extraction cycle, data from a continuous 10-second period during the stable operating phase in the middle of the extraction (the water pump operates at rated speed) is compared and analyzed. The detection deviation for each extraction cycle is calculated using the following formula: Detection deviation = (Detection value of the flow detection component under test - Detection value of the standard flow meter) / Detection value of the standard flow meter × 100% The extraction was run continuously for 10 cycles, and the average absolute value of the detection deviation in each cycle was taken as the final detection deviation for that group.

[0048] (ii) Pressure detection accuracy test Install the standard pressure sensor at the inlet of the extraction chamber. Start the coffee machine and operate according to the preset pressure curve. The data acquisition system simultaneously records the output signal of the pressure detection component under test and the output signal of the standard pressure sensor. In each extraction cycle, data from a continuous 10-second period during the stable operating phase in the middle of the extraction (the water pump operates at rated speed) is compared and analyzed. Calculate the pressure detection deviation for each extraction cycle using the following formula: Pressure detection deviation = (Detection value of the pressure detection component under test - Detection value of the standard pressure sensor) / Detection value of the standard pressure sensor × 100% After running for 10 consecutive extraction cycles, the average absolute value of the pressure detection deviation in each cycle is taken as the final pressure detection deviation for that group.

[0049] Example 1 and Comparative Examples 1-3 were compared under the same test conditions using the test methods described above. The results are as follows:

[0050] The test results above show that: In Comparative Example 1, without any obstruction structure, air bubbles directly enter the water intake and reach the flow detection component, resulting in a flow signal fluctuation of ±15% and a flow deviation of ±12%. In Comparative Example 2, although the obstruction structure eliminated air bubbles, the flow rate detected at the pump output after the flow meter was placed at the front end of the water circuit showed a transmission deviation of approximately ±10% between the flow rate detected and the actual water volume entering the extraction chamber after passing through the heating tube buffer. In Comparative Example 3, although the flow detection indicators were normal, the pressure detection system, connected in series to the main water circuit, caused the frictional resistance to cause the pressure detection value to deviate from the actual value by approximately ±8%.

[0051] In Comparative Examples 1 and 2, the pressure detection deviation was ≤±3%, slightly higher than ≤±2% in Example 1, but lower than ≥±8% in Comparative Example 3. In Example 1 and Comparative Examples 1 and 2, the pressure detection components were all connected via a three-way bypass, with the end of the branch closed and no continuous water flow. The pressure sensor sensed the static pressure of the water at that point. Therefore, the three schemes were identical in their basic pressure detection structure. The difference lay in the water flow state upstream of the pressure detection component. In Example 1, air bubbles were eliminated from the water inlet, and the flow meter was positioned downstream so that the flow rate output had been buffered by the heating tube. The water entering the extraction chamber was in a stable single-phase liquid state, and the water flow at the three-way node was smooth and the pressure field was uniform, so the pressure sensor obtained a stable static pressure signal. In Comparative Examples 1 and 2, although the pressure detection component was still connected via a three-way bypass, the lack of a barrier structure allowed air bubbles to enter the main flow. Therefore, the dynamic disturbance generated when air bubbles continuously passed through the three-way node was transmitted to the pressure-sensing diaphragm through the stagnant water, resulting in a relative decrease in the stability of the pressure detection.

[0052] This invention has been described through preferred embodiments. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. This invention is not limited to the specific embodiments disclosed herein; other embodiments falling within the scope of the claims are also within the protection scope of this invention.

Claims

1. A piping system for a coffee machine, characterized in that, include: The heating assembly (1) has a heating tube (11) and a water outlet (12) inside, and the water outlet (12) is used to draw out the water heated by the heating tube (11); A flow detection component (2) is located downstream of the water intake (12) and is used to detect the amount of water flowing through the waterway; The pressure detection component (3) is connected to the pipeline between the downstream of the flow detection component (2) and the extraction chamber (6) via a three-way structure (4). The first port (41) of the three-way structure (4) is connected to the downstream pipeline of the flow detection component (2), the second port (42) of the three-way structure (4) is connected to the inlet of the extraction chamber (6), and the third port (43) of the three-way structure (4) is connected to the pressure detection component (3). The water inlet (12) and the bubble-generating area of ​​the heating tube (11) are provided with a barrier structure, which is located on the path of the bubble moving from the bubble-generating area to the water inlet (12).

2. The pipeline system according to claim 1, characterized in that: The heating assembly (1) also includes a water intake section (13), on which the water intake section (13) is provided with the water intake port (12). The heating tube (11) is located on one side of the water intake section (13), and the water intake port (12) is located on the opposite side away from the heating tube (11).

3. The piping system according to claim 2, characterized in that: The minimum distance d2 between the water intake part (13) and the heating pipe (11) is 15mm ≥ d2 ≥ 4mm.

4. The piping system according to claim 1, characterized in that: A control valve (5) is also provided in the downstream pipeline of the flow detection component (2). The control valve (5) is located between the flow detection component (2) and the three-way structure (4), and the inner diameter of the pipeline from the outlet of the control valve (5) to the extraction chamber (6) is smaller than the inner diameter of the pipeline before the inlet of the control valve (5).

5. The piping system according to claim 4, characterized in that: The flow detection component (2) is arranged adjacent to the control valve (5), and the pipeline length between the outlet of the flow detection component (2) and the inlet of the control valve (5) is ≤5cm.

6. The piping system according to claim 4, characterized in that: The pipeline between the outlet of the control valve (5) and the inlet of the extraction chamber (6) has a gradient change in diameter, with the end diameter being smaller than the front diameter.

7. The piping system according to claim 1, characterized in that: The flow detection component (2) is equipped with a quick-release connection structure.

8. The piping system according to claim 1, characterized in that: The flow detection component (2) is a high-temperature resistant flow meter.

9. The piping system according to claim 1, characterized in that: The heating tube (11) has an upward stepped structure.

10. A coffee machine, characterized in that: Includes the piping system for a coffee machine as described in any one of claims 1-9.

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