Flow detection device for breathing machine and breathing machine

Abstract

The flow detection device comprises a shell, an airflow channel is arranged in the shell, and an air resistance structure is arranged in the airflow channel so that the airflow channel can be divided into an air inlet section located on one side of the air resistance structure and an air outlet section located on the other side of the air resistance structure. The air resistance structure is at least provided with a ventilation grid part in the middle area of the airflow channel, the shell is provided with a detection opening corresponding to the air inlet section and provided with a detection pipe extending into the air outlet section corresponding to the air outlet section, and the tail end of the detection pipe extends to the ventilation grid part to detect airflow passing through the ventilation grid part. The ventilation grating part is separated to form a plurality of airflow passing ports arranged in an array mode, airflow can be divided into a plurality of strands to pass through when passing through, the stability of the flow state of the airflow can be guaranteed, and the airflow can pass through the detection pipe in the air outlet section in a laminar flow state. The detection pipe can cross a viscous area close to the channel wall to directly detect the airflow in the central area of the airflow channel.

Description

Technical Field

[0001] This utility model belongs to the field of medical equipment technology, specifically relating to a flow detection device for a ventilator and a ventilator. Background Technology

[0002] A flow meter is typically installed in the air inlet duct of a ventilator to monitor the airflow rate inside the ventilator in real time. Some ventilators use laminar flow meters for flow measurement. A laminar flow meter is a differential pressure flow meter consisting of a laminar flow sensor and a differential pressure gauge. It measures the flow rate by measuring the differential pressure across the sensor. Its advantages are that the differential pressure ΔP measured by the flow meter is proportional to the volumetric flow rate Qv, and its structure is simple. However, as its name suggests, a laminar flow meter must be used under laminar flow conditions, and the fluid viscosity should remain constant.

[0003] In existing technologies, detection ports are often opened on the inlet duct wall of the flow meter, with one detection port located at the front end of the sensor and the other at the rear end of the sensor. This method results in the detection position being close to the pipe wall. However, during the airflow process, a viscous zone is formed near the pipe wall, which causes the airflow velocity in this area to decrease and the pressure drop to decrease. This results in a lower signal strength and lower signal accuracy detected by the laminar flow meter.

[0004] In addition, laminar flow meters have high requirements for the stability of airflow. When the airflow velocity in the duct is too high, the flow state may change from laminar to turbulent (Reynolds number exceeds the limit), thereby destroying the linear relationship. This will also lead to inaccurate results from the flow meter, resulting in large deviations and affecting the accuracy of the detection. Utility Model Content

[0005] This invention provides a flow detection device and a ventilator for use in ventilators, which solves the problems of low detection accuracy and signal strength caused by poor selection of the detection position of the flow meter, and the inability to control the flow velocity in the channel, which affects the detection accuracy.

[0006] The technical solution adopted in this utility model is as follows:

[0007] A flow detection device for a ventilator includes a housing with an airflow channel inside. An air resistance structure is provided inside the airflow channel to divide the airflow channel into an inlet section located on one side of the air resistance structure and an outlet section located on the other side of the air resistance structure. The air resistance structure has a ventilation grille at least in the middle region of the airflow channel to connect the inlet section and the outlet section. The housing has a detection port corresponding to the inlet section and a detection tube extending into the outlet section corresponding to the outlet section. The end of the detection tube extends to the ventilation grille to detect the airflow passing through the ventilation grille.

[0008] The projection of the end of the detection tube toward the air resistance structure is located inside the ventilation grille or flush with the edge of the ventilation grille.

[0009] The housing has a first housing wall, the detection tube is disposed on the first housing wall, the air resistance structure has a proximal end near the first housing wall and a distal end away from the first housing wall, and the venting grille is located in the central region of the air resistance structure; or, the venting grille extends from the central region of the air resistance structure to the distal end.

[0010] The ventilation grille has multiple first air inlets, and the air resistance structure also includes a flow passage, which has a second air inlet. The flow cross-sectional area of ​​the first air inlets is smaller than that of the second air inlets.

[0011] There are multiple second air passages, and there are partition ribs between the multiple second air passages. In the direction of airflow, the width of the partition ribs gradually increases so that the flow cross-sectional area at the inlet end of the second air passage is greater than the flow cross-sectional area at the outlet end of the second air passage.

[0012] The intake section has an intake end and an outlet end. The flow cross-sectional area of ​​the intake end is larger than that of the outlet end, so as to form a flow guiding transition surface on the inner wall of the intake section.

[0013] The flow guide transition surface includes a flow guide arc surface disposed on the inner wall of at least one side of the intake section.

[0014] The air resistance structure is positioned close to the air outlet of the airflow channel so that the length of the air inlet section is greater than the length of the air outlet section along the airflow direction.

[0015] The detection tube and the air resistance structure are integrally molded.

[0016] The cross-section of the airflow channel at the air resistance structure is rectangular, and the aspect ratio of the rectangle is not less than 2.

[0017] This utility model also discloses a ventilator, including a main unit, an installation cavity inside the main unit, a fan assembly and an air inlet duct inside the installation cavity, the air inlet duct being connected to the inlet of the fan assembly, and the aforementioned ventilator flow detection device being disposed inside the air inlet duct.

[0018] Due to the adoption of the above technical solution, the beneficial effects achieved by this utility model are as follows:

[0019] 1. The flow detection device of this utility model detects the flow rate of air by detecting the air pressure difference between the inlet section and the outlet section of the airflow channel. The air resistance structure located between the inlet section and the outlet section has a ventilation grille in the middle of the airflow channel. The ventilation grille is divided into multiple arrayed airflow passages. When the airflow passes through, it will be divided into multiple streams, which can reduce the flow velocity of the airflow. Moreover, the reduction of the flow area also makes the ventilation grille a laminar flow element, which can ensure the stability of the airflow state and make the airflow pass through the detection tube in the outlet section in a laminar flow state, thus ensuring the detection accuracy.

[0020] In addition, the detection tube located in the air outlet section extends into the airflow channel so that its end is located at the ventilation grille section. Since the ventilation grille section is located in the middle area of ​​the airflow channel, the detection tube can not only bypass the viscous area near the channel wall to directly detect the airflow in the central area of ​​the airflow channel, but also this part of the airflow has been subdivided and sorted by the ventilation grille section, which makes the detection signal stronger and further improves the detection accuracy.

[0021] 2. In a preferred embodiment of this utility model, the projection of the end of the detection tube toward the air resistance structure is located inside the ventilation grille or flush with the edge of the ventilation grille. The end of the detection tube extending to the edge of the ventilation grille or located inside the ventilation grille allows it to pass over the airflow located on the inner wall of the airflow channel, preventing the airflow in that area from affecting the detection results. Furthermore, it enables timely detection of the airflow that has been subdivided and combed by the ventilation grille, improving detection timeliness and accuracy, and reducing the impact of non-laminar airflow on the detection.

[0022] 3. In a preferred embodiment of this utility model, the ventilation grille has multiple first air passages, and the air resistance structure also includes a flow passage with a second air passage. The flow cross-sectional area of ​​the first air passage is smaller than that of the second air passage. The small-diameter first air passages on the ventilation grille can subdivide the airflow in the intake section into multiple streams, improving detection accuracy. However, if the intake and exhaust sections are only connected through the first air passages on the ventilation grille, the airflow will encounter significant resistance when passing through the air resistance structure, resulting in a large pressure drop and severe pressure loss, leading to low intake efficiency of the ventilator. Simultaneously, due to the significant resistance encountered by the airflow at the air resistance structure, a large amount of airflow converges in the intake section, increasing the air pressure and generating significant noise, affecting the user experience. In this invention, the air resistance structure is further provided with a flow passage, which has a second air passage with a flow cross-sectional area larger than that of the first air passage. This allows part of the airflow in the intake section to pass through the first air passage and be detected by the detection tube, while part of the airflow passes through the second air passage and enters the exhaust section. The airflow experiences less resistance when passing through the second air passage, thus reducing the air pressure in the intake section. This helps to reduce noise and pressure loss, ensuring detection accuracy while allowing the airflow to pass through the air resistance structure more efficiently, thereby ensuring the overall intake efficiency of the machine.

[0023] 4. In a preferred embodiment of this utility model, there are multiple second air passages, and there are separating ribs between the multiple second air passages. In the direction of airflow, the width of the separating ribs gradually increases, so that the flow cross-sectional area of ​​the inlet end of the second air passage is larger than the flow cross-sectional area of ​​the outlet end of the second air passage. The second air passage has a structure with a large inlet and a small outlet. The large inlet end makes it easier for the airflow in the intake section to pass through, and can reduce the air resistance of the intake, allowing the airflow to quickly and smoothly pass through the air resistance structure into the outlet section, improving the overall airflow efficiency and the overall intake efficiency of the machine, and also helping to reduce the noise generated when the airflow is obstructed, thus improving the noise reduction effect. The small outlet end can also subdivide and sort the airflow passing through the flow section, so that the airflow is subdivided into multiple streams after passing through the second air passage, thereby reducing the probability of turbulence or viscous regions in the outlet section, and making the airflow in the airflow channel flow as laminarly as possible.

[0024] 5. In a preferred embodiment of this utility model, the air inlet section has an inlet end and an outlet end. The flow cross-sectional area of ​​the inlet end is larger than that of the outlet end, forming a flow guiding transition surface on the inner wall of the air inlet section. The inlet end has a flared structure, which increases the flow cross-sectional area, allowing for the collection of airflow over a wider range. This ensures that the airflow in the ventilator duct passes through the flow detection device as much as possible, improving detection accuracy. The outlet end has a smaller flow cross-sectional area, which allows the airflow in the air inlet section to converge, making it pass more concentratedly through the air resistance structure and be detected on both sides of the air resistance structure. This increases the strength of the detection signal and improves detection accuracy. The flow guiding transition surface makes the process of the airflow in the air inlet section from being relatively dispersed to gradually converging smoother, ensuring airflow efficiency, reducing pressure loss, and preventing the airflow from drastically changing direction and generating noise. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0026] Figure 1 This is a schematic diagram of the flow detection device according to one embodiment of the present invention;

[0027] Figure 2 for Figure 1 Cross-sectional view of the medium flow detection device;

[0028] Figure 3 This is a front view of a flow detection device according to one embodiment of the present invention;

[0029] Figure 4 This is a rear view of a flow detection device according to one embodiment of the present invention;

[0030] Figure 5 This is a rear view of the flow detection device according to another embodiment of the present invention;

[0031] Figure 6 This is a rear view of the flow detection device according to another embodiment of the present invention;

[0032] Figure 7 This is a cross-sectional view of a flow detection device according to one embodiment of the present invention;

[0033] Figure 8 This is a cross-sectional view of a ventilator according to one embodiment of the present invention.

[0034] in:

[0035] 1. Shell; 11. Airflow channel; 111. Inlet section; 1111. Inlet end; 1112. Outlet end; 112. Outlet section; 12. Air resistance structure; 121. Ventilation grille; 1211. First air passage; 1212. Isolation rib; 122. Flow passage; 1221. Separation rib; 1222. Second air passage; 1223. Inlet end; 1224. Outlet end; 123. Proximal end; 124. Distal end; 13. Detection port; 14. Detection tube; 15. Guide transition surface; 16. First shell wall;

[0036] 2. Ventilator; 21. Air inlet duct; 22. Fan assembly. Detailed Implementation

[0037] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0039] Furthermore, it should be understood in the description of this utility model that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0040] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0041] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "implementation," "example," "aspect," or "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] like Figure 1 , Figure 2 As shown, a flow detection device for a ventilator 2 includes a housing 1. The housing 1 has an airflow channel 11 inside. An air resistance structure 12 is provided inside the airflow channel 11 to divide the airflow channel 11 into an inlet section 111 located on one side of the air resistance structure 12 and an outlet section 112 located on the other side of the air resistance structure 12. The air resistance structure 12 has a ventilation grille section 121 at least in the middle region of the airflow channel 11 to connect the inlet section 111 and the outlet section 112. The housing 1 has a detection port 13 corresponding to the inlet section 111 and a detection tube 14 extending into the outlet section 112 corresponding to the outlet section 112. The end of the detection tube 14 extends to the ventilation grille section 121 to detect the airflow passing through the ventilation grille section 121.

[0043] The flow detection device of this utility model detects the flow rate of the air by detecting the air pressure difference between the inlet section 111 and the outlet section 112 of the airflow channel 11. The air resistance structure 12 located between the inlet section 111 and the outlet section 112 has a ventilation grille section 121 in the middle of the airflow channel 11. The ventilation grille section 121 is divided into multiple arrayed airflow passages. When the airflow passes through, it will be divided into multiple streams, which can reduce the flow velocity of the airflow. Moreover, the reduction of the flow area also makes the ventilation grille section 121 a laminar flow element, which can ensure the stability of the airflow state and make the airflow pass through the detection tube 14 in the outlet section 112 in a laminar flow state, thus ensuring the detection accuracy.

[0044] Furthermore, the detection tube 14 located in the air outlet section 112 extends into the airflow channel 11 so that its end is located at the ventilation grille section 121. Since the ventilation grille section 121 is located in the middle region of the airflow channel 11, the detection tube 14 can not only bypass the viscous area near the channel wall to directly detect the airflow in the central region of the airflow channel 11, but also this part of the airflow has been subdivided and sorted by the ventilation grille section 121, thereby making the detection signal stronger and further improving the detection accuracy.

[0045] Preferably, such as Figure 3 As shown, from a perspective of looking directly at the air resistance structure 12, the ventilation grille portion 121 expands from the center of the air resistance structure 12 (which is also the airflow channel 11) to at least one of the following sides: upward, downward, left, and right.

[0046] It should be noted that, in one embodiment, a pipe extending into the airflow channel 11 can also be provided at the detection port 13 of the air intake section 111, so that the pipe also extends to the ventilation grille section 121, thereby enabling the flow detection device to detect the airflow before and after passing through the ventilation grille section 121, so as to further improve the detection accuracy.

[0047] Preferably, the detection port 13 and the detection tube 14 are both located close to the air resistance structure 12 in the extension direction of the airflow channel 11, so that the airflow passing through the ventilation grille section 121 can be detected in a timely manner through the detection tube 14.

[0048] It should be noted that the present invention does not limit the ventilation structure of the air resistance structure 12. In one embodiment, other areas of the air resistance structure 12 are closed, and only the ventilation grille 121 connects the air inlet section 111 and the air outlet section 112. Therefore, the airflow in the air inlet section 111 can only flow to the air outlet section 112 through the ventilation grille 121.

[0049] As a preferred implementation method, such as Figure 3 As shown, the ventilation grille section 121 has a plurality of first air passages 1211, and the air resistance structure 12 further includes a flow passage 122, which has a second air passage 1222. The flow cross-sectional area of ​​the first air passage 1211 is smaller than the flow cross-sectional area of ​​the second air passage 1222.

[0050] The small-diameter first air passage on the ventilation grille 121 can subdivide the airflow in the intake section 111 into multiple streams, improving detection accuracy. However, if the intake section 111 and the outlet section 112 are connected only through the first air passage 1211 on the ventilation grille 121, the airflow will encounter significant resistance when passing through the air resistance structure 12, resulting in a large pressure drop and severe pressure loss, thus reducing the intake efficiency of the ventilator 2. At the same time, due to the significant resistance encountered by the airflow at the air resistance structure 12, a large amount of airflow converges in the intake section 111, increasing the air pressure and generating significant noise, affecting the user experience. In this invention, the air resistance structure 12 is also provided with an overflow section 122, which has a second air outlet 1222. The cross-sectional area of ​​the second air outlet 1222 is larger than that of the first air outlet 1211. This allows part of the airflow in the intake section 111 to pass through the first air outlet 1211 and be detected by the detection tube 14, while part of the airflow passes through the second air outlet 1222 and enters the outlet section 112. The airflow experiences less resistance when passing through the second air outlet 1222, thus reducing the air pressure in the intake section 111. This helps to reduce noise and pressure loss, ensuring detection accuracy while allowing the airflow to pass through the air resistance structure 12 more efficiently, thereby ensuring the overall intake efficiency of the machine.

[0051] This utility model does not limit the arrangement of the first air vent 1211. In a preferred embodiment, such as... Figures 3 to 6 As shown, the ventilation grille section 121 is provided with multiple horizontally and vertically extending isolation ribs 1212, which intersect to form first air passages 1211. The first air passages 1211 are square and distributed in a rectangular array. Of course, the shape of the first air passages 1211 can also be circular, triangular, honeycomb, or other shapes, and the arrangement of the first air passages 1211 can also be a ring array or other methods, which are not limited here.

[0052] The flow passage 122 can have a large-area second air passage 1222 to improve airflow efficiency. Of course, if... Figure 3 As shown, in a preferred embodiment, there are multiple second air passages 1222, and the multiple second air passages 1222 are separated by partition ribs 1221. By using partition ribs 1221 to form multiple second air passages 1222 in the flow passage 122, while ensuring airflow efficiency and effectively controlling the air pressure in the inlet section 111, the flow passage 122 can also play a certain role in subdividing and sorting the airflow, thereby further reducing the probability of turbulence in the outlet section 112, especially near the channel wall.

[0053] In this embodiment, the shape and arrangement of the second vent 1222 are not limited, as long as its flow cross-sectional area is larger than that of the first vent 1211. The partition ribs 1221 are also arranged in a crisscross pattern to form the second vent 1222.

[0054] Furthermore, such as Figure 7 As shown, in the direction of airflow, the width of the partition rib 1221 gradually increases so that the flow cross-sectional area of ​​the inlet end 1223 of the second air outlet 1222 is greater than the flow cross-sectional area of ​​the outlet end 1224 of the second air outlet 1222.

[0055] The second air outlet 1222 has a structure with a large inlet and a small outlet. The large inlet end 1223 allows the airflow in the intake section 111 to pass through more easily and reduces the air resistance of the intake. This allows the airflow to pass quickly and smoothly through the air resistance structure 12 into the outlet section 112, improving the overall airflow efficiency and the overall intake efficiency of the machine. It also helps to reduce the noise generated when the airflow is obstructed, thus improving the noise reduction effect. The small outlet end 1224 can also subdivide and sort the airflow passing through the flow section, so that the airflow is divided into multiple streams through the second air outlet 1222, thereby reducing the probability of turbulence or viscosity in the outlet section 112 and ensuring that the airflow in the airflow channel 11 flows in a laminar state as much as possible.

[0056] Preferably, such as Figures 4 to 6 As shown, the projection of the end of the detection tube 14 toward the air resistance structure 12 is located inside the ventilation grille section 121 or flush with the edge of the ventilation grille section 121.

[0057] The end of the detection tube 14 extends to the edge of the ventilation grille section 121 or is located inside the ventilation grille section 121. On the one hand, it can pass over the airflow located on the inner wall of the airflow channel 11, avoiding the airflow in that area from affecting the detection results. On the other hand, it can detect the airflow that has passed through the ventilation grille section 121 in a timely manner, improving the timeliness and accuracy of detection and reducing the impact of non-laminar airflow on the detection.

[0058] This utility model does not limit the position of the ventilation grille 121 on the air resistance structure 12. In a preferred embodiment, such as Figure 4 , Figure 5 As shown, the housing 1 has a first housing wall 16, the detection tube 14 is disposed on the first housing wall 16, the air resistance structure 12 has a proximal end 123 close to the first housing wall 16 and a distal end 124 away from the first housing wall 16, and the ventilation grille 121 is located in the central region of the air resistance structure 12.

[0059] The central region of the air resistance structure 12 corresponds to the central region of the airflow channel 11. During the airflow process, this region is not prone to airflow stagnation or other phenomena. Therefore, the ventilation grille 121 is set here to further subdivide and sort the airflow flowing in the central region using the grille structure, further avoiding turbulence in the high-speed airflow, and keeping the airflow in a laminar state in the outlet section 112 to further improve the strength and accuracy of the detection signal.

[0060] In this embodiment, the ventilation grille 121 is located in the central region, and the flow passage 122 is located on the upper and lower sides of the ventilation grille 121.

[0061] In another preferred embodiment, such as Figure 6 As shown, the housing 1 has a first housing wall 16, the detection tube 14 is disposed on the first housing wall 16, the air resistance structure 12 has a proximal end 123 near the first housing wall 16 and a distal end 124 away from the first housing wall 16, and the ventilation grille portion 121 extends from the central region of the air resistance structure 12 to the distal end 124.

[0062] The ventilation grille section 121 extends from the central region to the distal end 124. On the one hand, this increases the area of ​​the ventilation grille section 121, allowing more airflow in the inlet section 111 to reach the outlet section 112, effectively increasing the pressure drop and further improving detection accuracy. On the other hand, it also reduces the manufacturing difficulty of the air resistance structure 12, ensuring that the overall pressure drop of the ventilator 2 is not excessive, avoiding significant pressure loss and affecting intake efficiency. If the entire air resistance structure 12 were set as the ventilation grille section 121, i.e., the ventilation grille section 121 extends from the proximal end 123 to the distal end 124, although the pressure drop effect in the airflow channel 11 would be good and the detection accuracy would be higher, the pressure drop in the overall intake airway of the ventilator 2 would still be too large, resulting in significant pressure loss during intake and affecting intake efficiency and the air supply efficiency of the ventilator 2.

[0063] In this embodiment, the proximal end 123 is provided with an overflow section 122.

[0064] In a preferred embodiment, such as Figure 2 As shown, the intake section 111 has an intake end 1111 and an outlet end 1112. The flow cross-sectional area of ​​the intake end 1111 is larger than the flow cross-sectional area of ​​the outlet end 1112, so as to form a flow guiding transition surface 15 on the inner wall of the intake section 111.

[0065] The inlet end 1111 has a flared structure, which increases the flow cross-sectional area, allowing it to collect airflow over a wider range. This ensures that the airflow in the ventilator 2's duct passes through the flow detection device as much as possible, improving detection accuracy. The outlet end 1112 has a smaller flow cross-sectional area, which allows the airflow in the inlet section 111 to converge, making it pass more concentratedly through the air resistance structure 12 and be detected on both sides of the air resistance structure 12. This increases the strength of the detection signal and improves detection accuracy. The guide transition surface 15 makes the process of the airflow in the inlet section 111 from being relatively dispersed to gradually converging smoother, ensuring airflow efficiency, reducing pressure loss, and preventing abrupt airflow changes that could generate noise.

[0066] The flow-guiding transition surface 15 can be an inclined surface or an irregular curved surface, and preferably, such as... Figure 7 As shown, the flow guiding transition surface 15 includes a flow guiding arc surface disposed on at least one inner wall of the air intake section 111. The arc surface structure of the flow guiding surface makes the airflow guidance smoother and more gentle, allowing the airflow to gradually change direction without sharp turns, thereby avoiding turbulence and reducing noise generated by airflow turning. Furthermore, normally, the air intake duct 21 inside the ventilator 2 is an annular duct extending circumferentially along the fan assembly 22; therefore, the flow guiding arc surface more closely follows the extension direction of the air intake duct 21, allowing the airflow within the air intake duct 21 to enter the flow detection device more smoothly.

[0067] Specifically, the flow guiding transition surface 15 is disposed on the shell wall of the housing 1 on the side near the fan assembly 22. Of course, it can also be disposed on other walls of the housing 1.

[0068] Preferably, such as Figure 1 , Figure 7 As shown, the air resistance structure 12 is positioned close to the air outlet of the airflow channel 11 so that the length of the air inlet section 111 is greater than the length of the air outlet section 112 along the airflow direction.

[0069] Before passing through the ventilation grille section 121, the airflow needs to fully develop into a stable laminar flow state. A longer inlet section 111 provides sufficient space and time for the fluid to stabilize, helping to eliminate inlet effects, reduce the influence of turbulence or eddies, and improve measurement accuracy. Furthermore, stabilizing the flow through the longer inlet section 111 reduces the design and manufacturing requirements of the ventilation grille section 121 itself, lowering manufacturing difficulty. Since the airflow has already formed a stable flow state after passing through the ventilation grille section 121, the shorter outlet section 112 will not significantly affect the measurement results, while also reducing pressure drop and energy loss. In addition, the shorter outlet section 112 reduces dependence on outlet conditions, making it easier to integrate the flow detection device into the air inlet duct 21 of the ventilator 2.

[0070] Preferably, the detection tube 14 and the air resistance structure 12 are integrally formed. For example, the housing 1, the detection tube 14, and the air resistance structure 12 are all plastic structures, integrally formed by injection molding. This integral forming method fixes the relative positions of the detection tube 14 and the air resistance structure 12, thereby ensuring accurate detection results and avoiding deviations in the relative positions caused by assembly errors. Alternatively, the detection tube 14 and the air resistance structure 12 can be separate components, each assembled and fixed to the housing 1.

[0071] This invention does not limit the cross-sectional shape of the airflow channel 11. Preferably, such as... Figures 3 to 6 As shown, the cross-section of the airflow channel 11 at the air resistance structure 12 is rectangular, and the aspect ratio of the rectangle is not less than 2.

[0072] The rectangular cross-section airflow channel 11 is easier to manufacture using microfabrication techniques (such as etching and precision stamping) compared to circular and other shapes, especially in small and micro flow detection devices. Furthermore, the rectangular airflow channel 11 acts as a guide, helping to create a more stable laminar flow state internally. An airflow channel 11 with an aspect ratio of not less than 2 can better suppress turbulence generation because the airflow is more likely to form a stable laminar flow in a narrower direction. This design reduces lateral airflow within the airflow channel 11. Moreover, this design allows for better control of the airflow velocity distribution, making the velocity more uniform in the central region of the air resistance structure 12 (which is also the central region of the airflow channel 11), thereby improving flow detection accuracy. Furthermore, for the same cross-sectional area, the smaller hydraulic diameter of the airflow channel 11 effectively reduces fluid pressure drop and energy loss, which is particularly important for applications requiring low pressure loss, such as medical equipment.

[0073] Of course, the cross-section of the airflow channel 11 can also be circular or other shapes, which is not limited here. Alternatively, the cross-sectional shape of the airflow channel 11 may vary along its length. For example, the cross-section of the airflow channel 11 may be circular near the air inlet and outlet, while it may be rectangular at the air resistance structure 12.

[0074] like Figure 8 As shown, this utility model also discloses a ventilator 2, including a main unit, an installation cavity inside the main unit, a fan assembly 22 and an air inlet duct 21 inside the installation cavity, the air inlet duct 21 being connected to the inlet of the fan assembly 22, and also including the aforementioned flow detection device for the ventilator 2, the flow detection device being disposed inside the air inlet duct 21.

[0075] The flow detection device is located upstream of the fan assembly 22. After passing through the flow detection device, the airflow exits from its outlet and then enters the inlet of the fan assembly 22. This allows the flow detection device to not only detect the incoming airflow but also to utilize its internal air resistance structure 12 to regulate the airflow, ensuring a more orderly entry into the fan assembly 22. This improves intake efficiency and reduces noise generated when the airflow enters the fan assembly 22.

[0076] For any parts not mentioned in this utility model, existing technologies can be used or referenced.

[0077] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0078] The above description is merely an embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A flow detection device for a ventilator, comprising a housing, wherein the housing has an airflow channel inside, characterized in that, The airflow channel is provided with an air resistance structure to divide the airflow channel into an air inlet section located on one side of the air resistance structure and an air outlet section located on the other side of the air resistance structure. The air resistance structure is provided with a ventilation grille section in at least the middle region of the airflow channel to connect the air inlet section and the air outlet section. The housing is provided with a detection port corresponding to the air inlet section and a detection tube extending into the air outlet section corresponding to the air outlet section. The end of the detection tube extends to the ventilation grille section to detect the airflow passing through the ventilation grille section.

2. The flow detection device for a ventilator according to claim 1, characterized in that, The projection of the end of the detection tube toward the air resistance structure is located inside the ventilation grille or flush with the edge of the ventilation grille.

3. The flow detection device for a ventilator according to claim 1, characterized in that, The housing has a first shell wall, the detection tube is disposed on the first shell wall, the air resistance structure has a proximal end near the first shell wall and a distal end away from the first shell wall, and the vent grille is located in the central region of the air resistance structure; or, The ventilation grille extends from the central region of the air resistance structure to the distal end.

4. The flow detection device for a ventilator according to claim 1, characterized in that, The ventilation grille has multiple first air inlets, and the air resistance structure further includes a flow passage, which has a second air inlet. The flow cross-sectional area of ​​the first air inlets is smaller than that of the second air inlets.

5. The flow detection device for a ventilator according to claim 4, characterized in that, There are multiple second air passages, and there are partition ribs between the multiple second air passages. In the direction of airflow, the width of the partition ribs gradually increases so that the flow cross-sectional area of ​​the inlet end of the second air passage is greater than the flow cross-sectional area of ​​the outlet end of the second air passage.

6. The flow detection device for a ventilator according to claim 1, characterized in that, The air intake section has an air intake end and an air outlet end. The flow cross-sectional area of ​​the air intake end is larger than that of the air outlet end, so as to form a flow guiding transition surface on the inner wall of the air intake section.

7. The flow detection device for a ventilator according to claim 6, characterized in that, The flow guiding transition surface includes a flow guiding arc surface disposed on the inner wall of at least one side of the air intake section.

8. The flow detection device for a ventilator according to claim 1, characterized in that, The air resistance structure is positioned close to the air outlet of the airflow channel so that the length of the air inlet section is greater than the length of the air outlet section along the airflow direction.

9. The flow detection device for a ventilator according to claim 1, characterized in that, The detection tube and the air resistance structure are integrally formed.

10. The flow detection device for a ventilator according to claim 1, characterized in that, The cross-section of the airflow channel at the air resistance structure is rectangular, and the aspect ratio of the rectangle is not less than 2.

11. A ventilator, comprising a main unit, wherein the main unit has an internal mounting cavity, the mounting cavity has a fan assembly and an air inlet duct, the air inlet duct being connected to the inlet of the fan assembly, characterized in that, It also includes the flow detection device for a ventilator as described in any one of claims 1-10, wherein the flow detection device is disposed within the air inlet duct.

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