Thermal type gas flow sensor with acceleration compensation

Abstract

The invention relates to the technical field of sensors, in particular to a thermal gas flow sensor with an acceleration compensation function. The embodiment of the invention provides an acceleration compensation thermal gas flow sensor, which comprises a gas inlet channel, a main body and a gas outlet channel, the main body internally comprises a flow channel structure and a closed cavity structure, two ends of the flow channel structure are respectively communicated with the gas inlet channel and the gas outlet channel to form an open channel, and the closed cavity structure is communicated with the gas inlet channel and the gas outlet channel. The closed cavity structure is a closed cavity in the main body, the part, used for testing, of the flow channel structure is connected with a flow channel testing unit used for measuring temperature data in the flow channel structure in the thickness direction, and the closed cavity structure is connected with a closed testing unit used for measuring temperature data in the closed cavity structure in the thickness direction. The embodiment of the invention provides a thermal gas flow sensor with acceleration compensation, and can provide a flow sensor which has built-in compensation capability, is quick in response and is easy to implement.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to an acceleration-compensated thermal gas flow sensor. Background Technology

[0002] Thermal gas flow sensors have wide applications in micro-flow measurement fields such as biopharmaceuticals, medical equipment, industrial process control, and aerospace. To ensure measurement accuracy, the sensor must possess high sensitivity and good stability. However, traditional thermal gas flow sensors are susceptible to interference from natural convection and external acceleration fields in practical use. The temperature distribution shifts along the acceleration direction, leading to a significant increase in measurement error under micro-flow conditions. The acceleration effect also introduces additional thermal convection noise, severely limiting the sensor's accuracy and reliability.

[0003] Existing sensors mostly employ a single flow channel structure, lacking an effective compensation mechanism for acceleration effects, or relying solely on external calibration and algorithms for post-correction. This results in problems such as complex structure, compensation lag, and limited applicability. To achieve high-precision measurement of micro-flow gases under complex acceleration environments, it is necessary to start from the sensor structure design level and propose a flow sensor with built-in compensation capabilities, fast response, and ease of implementation. Summary of the Invention

[0004] This invention provides an acceleration-compensated thermal gas flow sensor, which can provide a flow sensor with built-in compensation capability, fast response and easy implementation.

[0005] In a first aspect, embodiments of the present invention provide an acceleration-compensated thermal gas flow sensor, including an inlet channel, a main body, and an outlet channel. The main body includes a flow channel structure and a closed cavity structure. The two ends of the flow channel structure are respectively connected to the inlet channel and the outlet channel to form an open channel. The closed cavity structure is a closed cavity inside the main body. The portion of the flow channel structure used for testing is connected in the thickness direction to a flow channel testing unit for measuring temperature data within the flow channel structure. The closed cavity structure is connected in the thickness direction to a closed testing unit for measuring temperature data within the closed cavity structure.

[0006] In one possible design, the flow channel structure includes a transition region flow channel and a main flow channel, the main flow channel being used as a test section.

[0007] In one possible design, the flow channel test unit includes a flow channel test PCB and a flow channel flow test chip connected thereto.

[0008] In one possible design, the enclosed test unit includes an enclosed test PCB and an enclosed cavity flow test chip connected thereto.

[0009] In one possible design, the main body comprises, along the thickness direction, a flow channel groove layer, a sensor support layer, and a closed groove layer in sequence; The flow channel groove layer is provided with grooves, and the closed groove layer is also provided with grooves. The sensor support layer is used to set the flow channel test unit and the closed test unit. The upper and lower parts of the sensor support layer are respectively connected to the flow channel groove layer and the closed groove layer, so as to cooperate with the grooves of the flow channel groove layer and the grooves of the closed groove layer to form the flow channel structure and the closed cavity structure.

[0010] In one possible design, the flow channel groove layer, the sensor support layer, and the closed groove layer are fastened by screws and threaded holes.

[0011] In one possible design, a sealing rubber ring is provided at the junction of the flow channel groove layer, the sensor support layer, and the closed groove layer.

[0012] In one possible design, both the flow channel flow test chip and the enclosed cavity flow test chip are MEMS thermal flow sensor chips.

[0013] In one possible design, the flow channel test unit and the closure test unit are precisely fixed to the corresponding positions of the sensor support layer by a support pin structure.

[0014] Secondly, embodiments of the present invention also provide a flow testing method for an acceleration-compensated thermal gas flow sensor, based on any of the flow sensors described above, the method comprising: The data from the closed test unit is used to compensate for the data from the flow channel test unit.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: (1) By using a dual-channel structure consisting of a gas channel and a sealed cavity, the temperature field distribution of traditional MEMS thermal flow sensors is easily affected by acceleration fields such as gravity. This effectively eliminates the interference of natural convection on the sensing signal during gas flow measurement and proposes an acceleration field interference compensation scheme based on differential compensation.

[0016] (2) By adopting a dual-channel, dual-chip structure, differential compensation method is applied to acceleration field compensation, realizing high-precision measurement of small flow gas in complex environment.

[0017] (3) In view of the problem that micro-flow gas high-precision measurement is easily affected by acceleration field interference, a technical solution with compact structure, convenient installation and significant compensation effect is proposed. It can work stably and reliably in practical applications and has good practicality and engineering promotion value. Attached Figure Description

[0018] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of an acceleration-compensated thermal gas flow sensor provided by the present invention; Figure 2 An exploded structural diagram of an acceleration-compensated thermal gas flow sensor provided by the present invention; Figure 3 This is a schematic diagram of the general structure of a MEMS thermal flow meter; Figure 4 This is a schematic diagram illustrating the effect of gravity on temperature distribution.

[0020] In the picture: 1-Intake channel; 2-Flow channel groove layer; 3-Sensor support layer; 4-Flow channel test PCB; 5-Closed cavity test PCB; 6-Flow channel flow test chip; 7-Closed cavity flow chip; 8-Closed cavity groove; 9-Support pin structure. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] In the description of the embodiments of the present invention, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or stated, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0023] In this specification, it should be understood that the directional terms such as "upper" and "lower" used in the description of the embodiments of the present invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. Furthermore, in the context, it should also be understood that when it is mentioned that one element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0024] Please refer to Figure 1 and Figure 2 This invention provides an acceleration-compensated thermal gas flow sensor, including an inlet channel 1, a main body, and an outlet channel. The main body includes a flow channel structure and a closed cavity structure. The two ends of the flow channel structure are connected to the inlet channel 1 and the outlet channel, respectively, to form an open channel. The closed cavity structure is a closed cavity inside the main body. The part of the flow channel structure used for testing is connected to a flow channel testing unit in the thickness direction for measuring the temperature data inside the flow channel structure. The closed cavity structure is connected to a closed testing unit in the thickness direction for measuring the temperature data inside the closed cavity structure.

[0025] This invention proposes a flow channel design scheme for an acceleration-compensated thermal gas flow sensor. Through a dual-flow channel and differential compensation structure, it effectively suppresses interference from natural convection and acceleration fields, achieving stable and accurate measurement of small-flow-rate gases. This scheme boasts advantages such as compact structure, direct compensation, and ease of integration and adjustment. While improving the sensor's environmental adaptability and measurement accuracy, it also enhances the product's competitiveness in the field of high-performance flow measurement.

[0026] In this embodiment, flow channel data and closure data are obtained through the flow channel test unit and the closure test unit, respectively. By processing the flow channel data and closure data, accurate flow data that eliminates the influence of the acceleration field can be obtained.

[0027] In some embodiments of the present invention, the flow channel structure includes a transition region flow channel and a main flow channel, the main flow channel being used as a test section.

[0028] In this embodiment, the gas is guided to flow smoothly through the transition zone flow channel and the main flow channel to test stable gas, thereby improving the accuracy of the test.

[0029] In some embodiments of the present invention, the flow channel test unit includes a flow channel test PCB4 and a flow channel flow test chip 6 connected thereto.

[0030] In some embodiments of the present invention, the closed test unit includes a closed test PCB and a closed cavity flow test chip 7 connected thereto.

[0031] In this embodiment, the flow channel test PCB4 and the flow channel flow test chip 6 together form the main flow channel measurement unit for actual flow measurement; the closed cavity test PCB5 and the closed cavity flow test chip 7 together form the closed cavity reference unit for reference comparison. These two units are precisely fixed at designated positions on the sensor support layer 3 by the support pin structure 9, so that the flow channel flow test chip 6 is suspended in the main flow channel to sense airflow, while the closed cavity flow test chip 7 is placed in a sealed cavity to monitor environmental changes, together realizing flow measurement with acceleration compensation.

[0032] In some embodiments of the present invention, the main body includes, in sequence along the thickness direction, a flow channel groove layer 2, a sensor support layer 3, and a closed groove layer; The flow channel groove layer 2 is provided with grooves, and the closed groove layer is also provided with grooves. The sensor support layer 3 is used to set the flow channel test unit and the closed test unit. The upper and lower parts of the sensor support layer 3 are respectively connected to the flow channel groove layer 2 and the closed groove layer, so as to cooperate with the grooves of the flow channel groove layer 2 and the grooves of the closed groove layer to form the flow channel structure and the closed cavity structure.

[0033] In some embodiments of the present invention, the flow channel groove layer 2, the sensor support layer 3, and the closed groove layer are fastened by screws and threaded holes.

[0034] In some embodiments of the present invention, a sealing rubber ring is provided at the junction of the flow channel groove layer 2, the sensor support layer 3 and the closed groove layer.

[0035] The functional layers are positioned and fastened together by mechanical means such as screws, forming a complete and working sensor system.

[0036] In this embodiment, the flow channel groove layer 2 mainly includes a support portion and a flow channel portion. The support portion is provided with mounting holes, which, together with screws and nuts, enable assembly with adjacent structural layers; the flow channel portion is designed with a transition area flow channel and a main flow channel to guide the smooth flow of gas. To achieve a seal, a rubber sealing ring is provided at the mating surface in this embodiment, and the flow channel groove layer 2 and the sensor support layer 3 are pressed together by screws to form a reliably sealed flow channel space.

[0037] The sensor support layer 3, as the core load-bearing structure, serves multiple functions in this embodiment, including support, flow channel forming, and cavity enclosure. Its support portion is used to achieve mechanical connection of the multi-layer structure; its flow channel portion, combined with the flow channel groove layer 2, forms a complete main flow channel; and its cavity enclosure portion, in conjunction with the cavity enclosure groove layer 8, forms a sealed chamber isolated from the main flow channel, providing a stable reference environment for acceleration compensation.

[0038] Please refer to Figure 3 and Figure 4In some embodiments of the present invention, the flow channel flow test chip 6 and the closed cavity flow test chip 7 are both MEMS thermal flow sensor chips.

[0039] The core sensing element of the flow measurement chip is a thermal flow meter structure chip based on MEMS technology, which typically includes a heating resistor and two temperature sensing resistors symmetrically arranged upstream and downstream of the gas flow. During operation, the heating resistor heats the gas, and the gas flow creates a temperature gradient upstream and downstream. By detecting the temperature difference between the two temperature sensing resistors, the gas flow velocity can be calculated, thus reflecting the gas flow rate.

[0040] In some embodiments of the present invention, the flow channel test unit and the sealing test unit are precisely fixed to the corresponding positions of the sensor support layer 3 by the support pin structure 9.

[0041] The support pin structure 9 is precisely fixed to the corresponding position of the sensor support layer 3, so that the flow channel flow test chip 6 is located in the main flow channel, and the closed cavity flow test chip 7 is placed inside the sealed cavity, thereby realizing the sensing and measurement of gas flow and acceleration compensation. This invention also provides a flow rate testing method for an acceleration-compensated thermal gas flow sensor, based on any of the flow sensors described above, the method comprising: The data from the closed test unit is used to compensate for the data from the flow channel test unit.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An acceleration-compensated thermal gas flow sensor, characterized in that, The device includes an air intake channel, a main body, and an air outlet channel. The main body includes a flow channel structure and a closed cavity structure. The two ends of the flow channel structure are respectively connected to the air intake channel and the air outlet channel to form an open channel. The closed cavity structure is a closed cavity inside the main body. The part of the flow channel structure used for testing is connected to a flow channel testing unit in the thickness direction for measuring the temperature data inside the flow channel structure. The closed cavity structure is connected to a closed testing unit in the thickness direction for measuring the temperature data inside the closed cavity structure.

2. The flow sensor according to claim 1, characterized in that, The flow channel structure includes a transition region flow channel and a main flow channel, the main flow channel being used as a test section.

3. The flow sensor according to claim 1, characterized in that, The flow channel testing unit includes a flow channel testing PCB and a flow channel flow test chip connected thereto.

4. The flow sensor according to claim 1, characterized in that, The closed test unit includes a closed test PCB and a closed cavity flow test chip connected thereto.

5. The flow sensor according to claim 1, characterized in that, The main body comprises, in sequence along the thickness direction, a flow channel groove layer, a sensor support layer, and a closed groove layer; The flow channel groove layer is provided with grooves, and the closed groove layer is also provided with grooves. The sensor support layer is used to set the flow channel test unit and the closed test unit. The upper and lower parts of the sensor support layer are respectively connected to the flow channel groove layer and the closed groove layer, so as to cooperate with the grooves of the flow channel groove layer and the grooves of the closed groove layer to form the flow channel structure and the closed cavity structure.

6. The flow sensor according to claim 5, characterized in that, The flow channel groove layer, the sensor support layer, and the closed groove layer are fastened by screws and threaded holes.

7. The flow sensor according to claim 5 or 6, characterized in that, A sealing rubber ring is provided at the junction of the flow channel groove layer, the sensor support layer and the closed groove layer.

8. The flow sensor according to claim 1, characterized in that, Both the flow channel flow test chip and the closed cavity flow test chip are MEMS thermal flow sensor chips.

9. The flow sensor according to claim 1, characterized in that, The flow channel test unit and the sealing test unit are precisely fixed to the corresponding positions of the sensor support layer by a support pin structure.

10. A flow rate testing method for an acceleration-compensated thermal gas flow sensor, characterized in that, Based on any one of the flow sensors described in claims 1-9, the method includes: The data from the closed test unit is used to compensate for the data from the flow channel test unit.

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