A split flow wide range flow sensor

Abstract

The utility model discloses a shunt type wide range flow sensor, include: flow channel shell, PCB board and detection chip, the flow channel shell includes casing and pipe station, the bottom of casing is provided with sample introduction flow channel, the bottom middle area of casing is provided with boss and the sample introduction flow channel of ring in the boss outside, the PCB board covers and sets in the outside of sample introduction flow channel and forms flow channel cavity, the pipe station is provided with the through groove, the detection chip is embedded on the PCB board. The utility model discloses through the PCB board cover and set in the outside of sample introduction flow channel and form flow channel cavity, and the detection chip is arranged in the flow channel cavity, thereby realizes the detection of the flow parameter of medium in flow channel cavity, and the outside of support station is ringed and is connected with the groove, thereby adds two flow channels on the both sides of support station, thereby through the guidance fluid shunt, reduces the actual detection flow of chip, reaches the effect of extension range.

Description

Technical Field

[0001] This utility model relates to the field of flow sensor technology, and in particular to a shunt wide-range flow sensor. Background Technology

[0002] MEMS, or Micro-Electro-Mechanical Systems, is a technology that combines micro-machining and microelectronics. Compared to traditional flow sensors, MEMS flow sensors offer significant advantages such as miniaturization, high precision, fast response, low power consumption, high integration, and high reliability. Based on their working principle, MEMS flow sensors can be broadly categorized into three types: piezoelectric, piezoresistive, and thermal transfer. Thermal transfer flow sensors utilize temperature changes to determine flow rate, requiring no mechanically moving miniature components for measurement; therefore, they exhibit higher stability and longer lifespan.

[0003] The working principle of a heat transfer flow sensor is to obtain the fluid flow rate by measuring the temperature change of the temperature-sensing resistors on both sides of a heater. When there is no flow, the resistors on both sides have the same temperature and therefore equal resistance. However, when fluid flows, the temperature distribution on both sides becomes asymmetrical, resulting in a difference in resistance, which is then used to obtain the voltage change value through a Wheatstone bridge. Different flow rates lead to different temperature distributions, thus producing different output voltages, ultimately establishing a correspondence between flow rate and output voltage.

[0004] The encapsulation channel of a MEMS flow sensor is the core interface connecting the external fluid and the sensor chip. It undertakes crucial functions such as stable flow guidance, thermal isolation, mechanical protection, and environmental shielding. Its design directly affects the sensor's measurement accuracy, long-term stability, and environmental adaptability. Fluid flow rate refers to the amount of fluid flowing through the effective cross-section of a closed pipe or open channel per unit time, also known as instantaneous flow rate. When flow rate is expressed in volume, it is called volumetric flow rate; when flow rate is expressed in mass, it is called mass flow rate. The volume of fluid flowing through a certain section of pipe per unit time is called the volumetric flow rate of that cross-section. The flow rate of a certain cross-sectional area is defined as the volume or mass of fluid flowing through the pipe channel per unit time, and is divided into volumetric flow rate and mass flow rate.

[0005] For high-flow / high-pressure scenarios, the conventional approach for existing MEMS thermal mass flow sensors is to increase the flow range by increasing the size of the sensor. However, this approach is difficult to apply in compact applications with limited space due to its large overall size. Therefore, there is an urgent need for a new flow sensor that can expand the flow range without increasing the overall structure. Utility Model Content

[0006] In view of the above problems, this utility model is proposed to provide a shunt wide-range flow sensor that overcomes or at least partially solves the above problems.

[0007] This invention provides a shunt-type wide-range flow sensor, comprising: a flow channel housing, a PCB board, and a detection chip; the flow channel housing includes a shell and two identical tube platforms, the shell having a rectangular cross-section; a sample inlet channel is provided at the bottom of the shell, a boss and a sample inlet channel surrounding the boss are provided in the middle area of ​​the bottom of the shell; the PCB board is covered on the outside of the sample inlet channel to form a flow channel cavity, the tube platforms are provided with a through slot, the outlet at the bottom of the slot communicating with the flow channel cavity; the detection chip is embedded on the PCB board, the detection chip being located within the flow channel cavity.

[0008] Optionally, the flow channel shell is integrally molded.

[0009] Optionally, a stepped groove is provided at the bottom edge of the housing, the PCB board is fitted into the stepped groove, and the connection between the PCB board and the stepped groove is sealed with sealant.

[0010] Optionally, the outlets of the two through slots are symmetrically distributed at both ends of the sample inlet channel, wherein the sample inlet channel is provided with a channel port near the outlet.

[0011] Optionally, the boss is provided with smooth inclined surfaces on both sides, and the inclined surfaces are inclined in the direction that the boss is inclined toward the flow channel ports on both sides.

[0012] Optionally, the PCB board is provided with flow guide grooves corresponding to the positions of the two tube platforms, and the PCB board is provided with a support platform corresponding to the position of the boss. The outer side of the support platform is provided with an annular connecting groove, which is connected to the two flow guide grooves respectively. The flow guide grooves and the annular connecting grooves are connected to the sample inlet channel to form the flow channel cavity.

[0013] Optionally, the detection chip is bonded to the support platform of the PCB board by die bond adhesive and electrically connected to the PCB board by wire bonding; the support platform is also provided with a receiving groove, the detection chip is placed in the receiving groove, and the top of the detection chip is flush with the surface of the support platform.

[0014] Optionally, the guide channel is horizontally provided with a stepped contour positioning groove at the outlet position at the bottom of the channel, and a filter section is provided in the contour positioning groove.

[0015] Optionally, the filtration section includes a filter screen and a support plate surrounding the outside of the filter screen. The filter screen is a perforated circular mesh structure, and the support plate is disposed in the contour positioning groove.

[0016] Optionally, the shape of the filter section matches the shape of the contour positioning groove.

[0017] The technical solution provided in this embodiment of the utility model has at least the following technical effects or advantages: The shunt-type wide-range flow sensor described in this embodiment of the invention forms a flow channel cavity by covering the outside of the sample inlet channel with a PCB board, and placing the detection chip inside the flow channel cavity to detect the flow parameters of the medium inside the flow channel cavity. Furthermore, a ring-connecting groove is provided around the outside of the support platform, which, by circling the periphery of the support platform, adds two flow channels on both sides of the support platform, enhancing the shunt effect. By guiding the fluid to flow separately, in high-flow / high-pressure scenarios, it reduces the actual flow rate detected by the chip without increasing the overall structural space, thereby achieving the effect of widening the measurement range. A stepped contoured positioning groove is horizontally provided at the outlet position of the bottom of the guide groove, opposite to the channel bottom. A filter section is provided inside the contoured positioning groove, which can filter impurities in the medium, avoiding interference from impurities and thus preventing them from affecting the accuracy of flow monitoring.

[0018] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an exploded view of the shunt wide-range flow sensor of this utility model. Figure 2 This is a schematic diagram of the PCB board structure described in this utility model; Figure 3 This is a top view of the housing described in this utility model; Figure 4 for Figure 3 A cross-sectional view along the AA direction; Figure 5 for Figure 3 Cross-sectional view along the BB direction; Figure 6 This is an isometric view of the housing described in this utility model; Figure 7 This is a schematic diagram of the filter section.

[0021] Explanation of reference numerals in the attached figures: 1. Housing; 2. PCB board; 3. Detection chip; 4. Filter section; 11. Tube platform; 12. Through groove; 13. Sample inlet channel; 14. Outlet; 15. Connecting ear; 16. Step groove; 20. Guide groove; 21. Contouring positioning groove; 22. Needle row; 23. Support platform; 24. Circular connecting groove; 41. Support plate; 42. Filter screen; 131. Channel port; 132. Boss; 133. Inclined surface. Detailed Implementation

[0022] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The accompanying drawings show preferred embodiments of the present invention. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0024] Unless otherwise specified, all raw materials, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0025] Figure 1 This is an exploded view of the shunt wide-range flow sensor described in this utility model. Figure 2 This is a schematic diagram of the PCB board described in this utility model. Figure 3 This is a top view of the housing described in this utility model. Figure 4 for Figure 3 Cross-sectional view along the AA direction. Figure 5 for Figure 3 Cross-sectional view along the BB direction. Figure 6 This is an isometric view of the housing described in this utility model. (See reference...) Figure 1-6As shown, the shunt wide-range flow sensor includes a flow channel housing, a PCB board 2, and a detection chip 3. The flow channel housing includes a shell 1 and two identical tube platforms 11. The shell 1 has a rectangular cross-section. A boss 132 and a sample inlet channel 13 surrounding the boss are provided in the middle area of ​​the bottom of the shell 1. The PCB board 2 covers the outside of the sample inlet channel 13 to form a flow channel cavity. The tube platform 11 is provided with a through groove 12, and the outlet 14 at the bottom of the through groove 12 communicates with the flow channel cavity. The detection chip 3 is embedded on the PCB board 2 and is located inside the flow channel cavity. The two tubes 11 serve as the medium injection port and the medium discharge port 14, respectively (that is, when one tube 11 serves as the medium injection port, the other tube 11 serves as the medium discharge port 14, and the functions of the two can be switched according to actual application requirements). The medium is introduced into the flow channel cavity through one of the tubes 11, and the detection chip 3 detects and collects the flow rate data of the medium in the flow channel cavity in real time. The medium finally flows out through the other tube 11.

[0026] In this embodiment of the utility model, the flow channel shell is integrally molded. The material of the flow channel shell is plastic, ceramic or polymer material, etc. Different manufacturing processes can be adopted according to different materials. The integral molding manufacturing process is, for example, injection molding, injection molding or compression molding.

[0027] Combination Figure 6 As shown, a stepped groove 16 is provided at the bottom edge of the housing 1, the PCB board 2 is attached to the stepped groove 16, and the connection between the PCB board 2 and the stepped groove 16 is sealed with a sealant, such as epoxy resin.

[0028] The sample inlet channel 13 is arranged around the periphery of the boss 132, thereby adding two flow channels on both sides of the boss 132 and enhancing the flow diversion effect; the outlets 14 of the two through slots 12 are symmetrically distributed at both ends of the sample inlet channel 13, wherein the sample inlet channel 13 is provided with the channel port 131 near the outlet 14, and the boss 132 is provided with smooth inclined surfaces 133 on both sides, the inclined direction of the inclined surfaces 133 being that the boss 132 is inclined towards the channel ports 131 on both sides.

[0029] The detection chip 3 is positioned directly opposite the protrusion 132, so that the medium enters the sample inlet channel 13 from the flow port 131 corresponding to the tube platform 11 (the injection port of the medium) and reaches the top of the protrusion 132 along the inclined surface 133, which allows the detection chip 3 to obtain more stable flow data.

[0030] Combination Figure 2 As shown in this embodiment of the present invention, the PCB board 2 is provided with flow guide grooves 20 corresponding to the positions of the two tube platforms 11, and the PCB board 2 is provided with a support platform 23 corresponding to the position of the boss 132. The outer side of the support platform 23 is provided with an annular connecting groove 24, which is connected to the two flow guide grooves 20 respectively. The flow guide grooves 20 and the annular connecting grooves 24 are connected to the sample inlet channel 13 to form the flow channel cavity. The medium is introduced into the flow guide groove 20 through one of the tube platforms 11, then input into the flow channel cavity through the annular connecting groove 24, and output from the other tube platform 11.

[0031] In this embodiment of the present invention, the detection chip 3 is bonded to the support platform 23 of the PCB board 2 by die-bonding adhesive and electrically connected to the PCB board 2 by wire bonding. In other embodiments of the present invention, the support platform 23 may also be provided with a receiving groove (not shown), the detection chip 3 is disposed in the receiving groove, and the top of the detection chip 3 is flush with the surface of the support platform 23. When the medium is at a high flow rate, it will generate a high Reynolds number and Nusselt number, which will lead to flow separation. The separated flow will reduce the performance of the sensor. By making the top of the detection chip 3 flush with the surface of the support platform 23, the influence of the detection chip 3 on the medium in the flow channel cavity can be avoided.

[0032] To avoid interference from impurities in the medium, the guide channel 20 is horizontally provided with a stepped contour positioning groove 21 at the outlet 14 at the bottom of the channel 12. The contour positioning groove 21 is provided with a filter section 4, which is used to filter the medium input to the outlet 14 at the bottom of the channel 12.

[0033] Figure 7 See the schematic diagram of the filter section 4. Figure 7 As shown, in this embodiment of the present invention, the filter part 4 includes a filter screen 42 and a support plate 41 surrounding the outside of the filter screen 42. The filter screen 42 is a circular mesh structure with holes. The support plate 41 is disposed in the contour positioning groove 21 to provide physical support. The shape of the filter part 4 matches the shape of the contour positioning groove 21. For example, when the shape of the filter part 4 is circular, the shape of the contour positioning groove 21 is also circular. In other embodiments, it can also be adjusted to other shapes according to actual application requirements. This embodiment of the present invention does not limit this.

[0034] The thickness of the support plate 41 matches the depth of the contour positioning groove 21. The thickness of the support plate 41 is 0.2 mm, the diameter of the support plate 41 is 3 mm, and the diameter of the filter screen 42 is 2 mm.

[0035] In this embodiment of the present invention, a pin header 22 is also provided on the side of the PCB board 2. The pin header 22 forms a connection port for electrical connection with external active devices to transmit data.

[0036] In this embodiment of the invention, the side of the flow channel shell may also be provided with a plurality of connecting ears 15, which are used to connect with the external support structure to provide physical support.

[0037] Compared with the prior art, the shunt-type wide-range flow sensor described in this embodiment of the invention has the following advantages: 1. The PCB board 2 is covered on the outside of the sample inlet channel 13 to form a flow channel cavity, and the detection chip 3 is placed in the flow channel cavity to realize the detection of the flow parameters of the medium in the flow channel cavity. The support platform 23 is provided with an annular connecting groove 24 on the outside. The annular connecting groove 24 is arranged around the periphery of the support platform 232, thereby adding two flow channels on both sides of the support platform 23, which enhances the flow diversion effect. By guiding the fluid diversion, in the case of high flow / high pressure, the actual detection flow of the chip is reduced without increasing the overall structural space, so as to achieve the effect of widening the measurement range. 2. The flow channel shell is integrally molded, which greatly simplifies the production difficulty, improves the efficiency and product consistency during mass production, and the integral flow channel shell reduces the installation process of parts during assembly, thus reducing the installation difficulty. 3. A raised boss 132 is provided in the middle area of ​​the sample inlet channel 13, and a smooth inclined surface 133 is provided between the boss 132 and the channel port 131. The sample inlet channel 13 is arranged around the boss 132, thereby adding two flow channels on both sides of the boss 132. In conjunction with the annular connecting groove 24 arranged around the outside of the support platform 23, the flow splitting effect is further significantly improved. 4. The top of the detection chip 3 is flush with the surface of the support platform 23. When the medium is at a high flow rate, it will generate a high Reynolds number and Nusselt number, which will lead to flow separation. The separated flow will reduce the performance of the sensor. By making the top of the detection chip 3 flush with the surface of the support platform 23, the influence of the detection chip 3 on the medium in the flow channel cavity can be avoided. 5. The guide channel 20 is horizontally provided with a stepped contour positioning groove 21 at the outlet 14 position at the bottom of the through channel 12. The contour positioning groove 21 is provided with a filter section 4. The filter section 4 can filter impurities (such as dust particles) in the medium, avoiding interference from impurities and thus affecting the accuracy of flow monitoring.

[0038] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0039] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and it should be noted that the above embodiments are illustrative of the invention and not restrictive, and that alternative embodiments can be devised by those skilled in the art without departing from its scope.

Claims

1. A shunt-type wide-range flow sensor, characterized in that, The shunt-type wide-range flow sensor includes: a flow channel housing, a PCB board, and a detection chip; the flow channel housing includes a shell and two identical tube platforms, the shell having a rectangular cross-section; a sample inlet channel is provided at the bottom of the shell, a boss and a sample inlet channel surrounding the boss are provided in the middle area of ​​the bottom of the shell; the PCB board is covered on the outside of the sample inlet channel to form a flow channel cavity, the tube platform is provided with a through slot, the outlet at the bottom of the slot is connected to the flow channel cavity; the detection chip is embedded on the PCB board, the detection chip being located inside the flow channel cavity.

2. The shunt-type wide-range flow sensor according to claim 1, characterized in that: The outer shell of the flow channel is integrally molded.

3. The shunt-type wide-range flow sensor according to claim 1, characterized in that: A stepped groove is provided at the bottom edge of the housing, the PCB board is fitted into the stepped groove, and the connection between the PCB board and the stepped groove is sealed with sealant.

4. The shunt-type wide-range flow sensor according to claim 1, characterized in that: The outlets of the two channels are symmetrically distributed at both ends of the sample inlet channel, and the sample inlet channel is provided with a channel port near the outlet.

5. The shunt-type wide-range flow sensor according to claim 4, characterized in that: The boss has smooth inclined surfaces on both sides, and the inclined surfaces are inclined in the direction that the boss is inclined toward the flow channel ports on both sides.

6. The shunt-type wide-range flow sensor according to claim 1, characterized in that: The PCB board is provided with flow guide grooves corresponding to the positions of the two tube platforms, and the PCB board is provided with support platforms corresponding to the positions of the bosses. The outer side of the support platform is provided with an annular connecting groove, which is connected to the two flow guide grooves respectively. The flow guide grooves and the annular connecting grooves are connected to the sample inlet channel to form the flow channel cavity.

7. The shunt-type wide-range flow sensor according to claim 6, characterized in that: The detection chip is bonded to the support platform of the PCB board by die bond adhesive and electrically connected to the PCB board by lead bonding; the support platform is also provided with a receiving groove, the detection chip is placed in the receiving groove, and the top of the detection chip is flush with the surface of the support platform.

8. The shunt-type wide-range flow sensor according to claim 6, characterized in that: The guide channel is horizontally positioned with a stepped contour positioning groove at the outlet position at the bottom of the channel, and a filter section is provided inside the contour positioning groove.

9. The shunt-type wide-range flow sensor according to claim 8, characterized in that: The filtration section includes a filter screen and a support plate surrounding the outside of the filter screen. The filter screen is a perforated circular mesh structure, and the support plate is disposed in the contour positioning groove.

10. The shunt-type wide-range flow sensor according to claim 9, characterized in that: The shape of the filter section matches the shape of the contour positioning groove.

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