Gas flow rate related gas pressure sensor

Abstract

The invention discloses a gas flow rate related gas pressure sensor, which comprises a first shell, a second shell and a substrate sheet arranged between the first shell and the second shell, the substrate sheet is made of an elastic material, a first gas cavity is formed between the first shell and the substrate sheet, and a second gas cavity is formed between the second shell and the substrate sheet. Resistance strain gauges are distributed on the two sides of the substrate sheet; the first air cavity is communicated with the second wall body through an air guide channel; the first shell is provided with an input interface, and the second shell is provided with an output interface; when the flow rate of gas is detected, the detected gas is introduced from the input interface and is discharged from the output interface; when the pressure intensity change rate generated by gas impact in the elastic closed gas chambers is detected, the input interface is connected with a first elastic closed gas chamber, and the output interface is connected with a second elastic closed gas chamber; and external collision impact is received through the first elastic closed air chamber. The requirements on the gas type and the environment temperature are greatly reduced, and the applicability is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to a gas flow rate-related air pressure sensor. Background Art

[0002] With the rapid development of modern industry, energy, aerospace, environmental monitoring and other fields, the demand for accurate measurement of gas flow rate is getting higher and higher. Some existing gas flow rate (flow) sensors usually measure gas flow rate (flow) based on the working principle of piezoresistive effect, piezoelectric effect, capacitance effect, etc. These traditional gas flow rate (flow) sensors have the following problems: 1. Insufficient sensitivity and stability, especially the response is not accurate enough in high dynamic change and high flow rate environments; 2. Affected by environmental factors, existing gas flow rate (flow) sensors have high requirements for ambient temperature, gas type, etc., and have strict installation requirements; 3. In some specific scenarios, such as collision and impact detection of robotic arms, the collision and impact detection is to measure the pressure change rate of the gas in the elastic closed air chamber when it is impacted and squeezed, so as to judge the magnitude of the impact force. In this usage scenario, there is usually a need to detect the gas flow rate and the gas pressure change rate; while traditional gas flow rate (flow) sensors have a single function and can usually only detect the gas flow rate, but cannot detect the gas pressure change rate caused by impact or squeezing, and therefore cannot meet the detection requirements of the above usage scenarios. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies in the prior art and provide a gas flow rate related air pressure sensor.

[0004] The objective of the present invention is achieved through the following technical solution: a gas flow rate-related air pressure sensor, comprising a first shell, a second shell, and a substrate sheet arranged between the first shell and the second shell, wherein the substrate sheet is made of an elastic material, a first air cavity is formed between the first shell and the substrate sheet, a second air cavity is formed between the second shell and the substrate sheet, and resistance strain gauges are arranged on both sides of the substrate sheet; the first air cavity is connected to the second wall through an air guide channel; an input interface is arranged on the first shell, and an output interface is arranged on the second shell; When detecting the gas flow rate, the gas to be measured is introduced from the input interface and discharged from the output interface; When detecting the pressure change rate of the gas in the elastic closed air chamber caused by the impact, the first elastic closed air chamber is connected to the input interface, and the second elastic closed air chamber is connected to the output interface; the external collision impact is received through the first elastic closed air chamber.

[0005] Preferably, the aperture of the input interface is larger than the aperture of the output interface, and the aperture of the output interface is larger than the aperture of the air guide channel.

[0006] Preferably, the base sheet is made of silicone material.

[0007] Preferably, the base sheet is sandwiched between the first shell and the second shell, the first shell and the second shell are connected by bolts, and a sealing ring groove is provided on one side of the second shell close to the base sheet, and a sealing ring is embedded in the sealing ring groove.

[0008] Preferably, the air guide channel includes a first channel section arranged on the first shell and a second channel section arranged on the second shell, the first channel section is connected to the second air cavity, the second channel section is connected to the second air cavity, and the first channel section is connected to the second channel section.

[0009] Preferably, the base sheet is provided with a through hole corresponding to the air guide channel, and an O-ring is provided between the base sheet and the first shell, and the O-ring is located at the periphery of the through hole.

[0010] As a preference, when detecting the gas flow rate, the measured gas flow rate The calculation formula is as follows: ; In the formula, is the lateral dimension of the base sheet; is the maximum deformation at the center of the substrate; the maximum deformation at the center of the substrate is obtained by measuring the resistance value of the resistance strain gauge; E is the elastic modulus of the substrate; h is the thickness of the substrate; D2 is the equivalent diameter of the actual ventilation area of ​​the first air cavity; L is the length of the first air cavity; is the density of the gas; f is the friction factor.

[0011] Preferably, when detecting the pressure change rate of the gas in the elastic closed air chamber caused by the impact, ; is the rate of change of the center deformation of the substrate, which is obtained by measuring the resistance value of the resistance strain gauge; E is the elastic modulus of the substrate; h is the thickness of the substrate; is the lateral dimension of the substrate.

[0012] The beneficial effects of the present invention are: 1. The sensor involved in the present invention can be applied to different types of other measurement requirements, has low requirements on gas types, and has no other electronic components except the resistance strain gauge inside the sensor, and there are no semiconductor devices with high temperature requirements inside. Therefore, the present invention greatly reduces the requirements for ambient temperature during measurement, and can work in a wider temperature range, greatly improving its applicability.

[0013] 2. The present invention has high measurement sensitivity and is particularly suitable for gas measurement needs in highly dynamic and high flow rate environments.

[0014] 3. The present invention is sturdy and durable, has low installation requirements, and can maintain normal operation in harsh environments.

[0015] 4. The present invention can not only measure the gas flow rate (flow), but also measure the pressure change rate caused by the impact of the gas in the elastic closed gas chamber, which solves the problem of single function of traditional gas flow rate (flow) meters and meets the use requirements in some special scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention.

[0017] Figure 2 It is a cross-sectional view of the present invention.

[0018] Figure 3 It is a schematic structural diagram of the substrate of the present invention.

[0019] Figure 4 A side view of the substrate.

[0020] Figure 5 It is a schematic diagram of the present invention when detecting gas flow rate.

[0021] Figure 6 It is a schematic diagram of the present invention when detecting the pressure change rate caused by the impact of gas in the elastic closed air chamber.

[0022] In the figure: 1. first shell, 2. second shell, 3. input interface, 4. output interface, 5. base plate, 6. first air cavity, 7. second air cavity, 8. resistance strain gauge, 9. first channel section, 10. second channel section, 12. O-ring, 13. through hole, 14. first elastic closed air chamber, 15. second elastic closed air chamber. DETAILED DESCRIPTION

[0023] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0024] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0025] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0026] like Figures 1 to 5 As shown, a gas flow rate-related air pressure sensor comprises a first shell 1, a second shell 2, and a substrate 5 arranged between the first shell 1 and the second shell 2, wherein the substrate 5 is made of an elastic material, a first air cavity 6 is formed between the first shell 1 and the substrate 5, a second air cavity 7 is formed between the second shell 2 and the substrate 5, and resistance strain gauges 8 are arranged on both sides of the substrate 5; the first air cavity 6 is connected to the second wall through an air guide channel; an input interface 3 is arranged on the first shell 1, and an output interface 4 is arranged on the second shell 2; When detecting the gas flow rate, the gas to be measured is introduced from the input interface 3 and discharged from the output interface 4; When detecting the pressure change rate of the gas in the elastic closed air chamber caused by the impact, the first elastic closed air chamber 14 is connected to the input interface 3, and the second elastic closed air chamber 15 is connected to the output interface 4; the first elastic closed air chamber 14 receives the external collision impact.

[0027] The aperture of the input interface 3 is larger than the aperture of the output interface 4 , and the aperture of the output interface 4 is larger than the aperture of the air guide channel.

[0028] The resistance strain gauge 8 is connected to a signal acquisition card, and the resistance of the resistance strain gauge 8 is acquired in real time by the signal acquisition card.

[0029] When detecting the gas flow rate, the measured gas enters the first air cavity 6 through the output interface 4 at a fixed flow rate, then enters the second air cavity 7 through the air guide channel, and is finally discharged through the output interface 4; according to the Bernoulli principle, after entering the first air cavity 6, the actual gas passing area between the first air cavity 6 and the air guide channel shrinks, and under the action of gas viscosity, the pressure in the first air cavity 6 will be greater than the pressure in the second air cavity 7, and because the flow rate of the measured gas is fixed, the pressure difference on both sides of the substrate sheet 5 is kept constant. At this time, the substrate sheet 5 will deform and bulge toward the direction of the second air cavity 7 and form a stable deformation state. The deformation bulge of the sheet 5 will drive the resistance strain gauges 8 on both sides to produce a stable deformation; so that the resistance strain gauge 8 reaches a stable resistance value; because the pressure difference on both sides of the substrate sheet 5 determines the maximum deformation of the center of the substrate sheet 5, thereby determining the deformation degree of the resistance strain gauge 8, and then determining the resistance value of the resistance strain gauge 8, therefore, the resistance value of the resistance strain gauge 8 corresponds to the maximum deformation of the center of the substrate sheet 5, and the resistance value of the resistance strain gauge 8 corresponds to the pressure difference value on both sides of the substrate sheet 5; that is, as long as the resistance value of the resistance strain gauge 8 is obtained, the maximum deformation of the center of the substrate sheet 5 can be obtained. The corresponding relationship between the maximum deformation of the center of the substrate sheet 5 and the resistance value of the resistance strain gauge 8 can be measured in advance, so that in the actual detection process, the resistance value of the resistance strain gauge 8 can be collected in real time by the signal acquisition card, and the maximum deformation of the center of the substrate sheet 5 can be obtained, and then the pressure difference on both sides of the substrate sheet 5 can also be obtained; the flow rate of the gas can be calculated with the help of Bernoulli's principle.

[0030] The present invention detects the gas flow rate by using the difference in the aperture sizes of the output interface 4 and the input interface 3 and the principles of air viscosity and fluid mechanics.

[0031] Specifically, when detecting the gas flow rate, the measured gas flow rate The calculation formula is as follows: ; In the formula, is the lateral dimension of the base sheet, in meters; is the maximum deformation at the center of the substrate, in meters; the maximum deformation at the center of the substrate is obtained by measuring the resistance of the strain gauge; E is the elastic modulus of the substrate, in Pascals (Pa); h is the thickness of the substrate in meters; D2 is the equivalent diameter of the actual ventilation area of ​​the first air cavity, in meters; L is the length of the first air cavity, in meters; is the density of the gas; is the friction factor, a dimensionless value determined by the Reynolds number and the surface roughness of the internal channel of the sensor).

[0032] The calculation formula of friction factor is as follows: ; In the formula, is the friction factor; ϵ is the surface roughness of the internal channel of the sensor; is the equivalent diameter of the actual ventilation area of ​​the first air cavity; is the Reynolds number.

[0033] It is worth mentioning that since the aperture of the input interface 3 is known, after measuring the flow rate of the gas, the volume of gas passing through the input interface 3 per unit time (ie, the gas flow rate) can be calculated according to the aperture of the input interface 3 .

[0034] When detecting the pressure change rate of the gas in the elastic closed air chamber caused by the impact, the input interface 3 and the output interface 4 are respectively connected to an elastic closed air chamber. Since the first elastic closed air chamber 14 and the second elastic closed air chamber 15 are connected through the first air cavity 6, the air guide channel and the second air cavity 7, the gas pressure inside the first elastic closed air chamber 14 and the second elastic closed air chamber 15 is the same in a static state; when the first elastic closed air chamber 14 is impacted, the gas inside the first elastic closed air chamber 14 enters the sensor through the input interface 3, and the gas will pass through the first air cavity 6, the air guide channel and the second air cavity 7 in turn, and then flow out through the output interface 4 and enter the second elastic closed air chamber 15. Since the gas has viscosity, the pressure of the first air cavity 6 will increase, thereby generating a pressure difference on both sides of the substrate 5. After the impact stops, the pressure on both sides of the substrate 5 gradually returns to an equal state. In the process from the occurrence of impact to the stop, the base sheet 5 will drive the strain gauge to produce a deformation from strong to weak. At this time, the change in the resistance value of the resistance strain gauge 8 is read by the signal acquisition card. Since the resistance value at each moment corresponds one-to-one to the pressure difference on both sides of the base sheet 5, and also corresponds one-to-one to the deformation amount at the center of the base sheet 5, the resistance value of the resistance strain gauge 8 is measured, and the rate of change of the air pressure in the first elastic closed air chamber 14 during the impact process can be calculated. The present invention distinguishes the diameters of large-diameter vents and small-diameter vents, and utilizes the principles of air viscosity and fluid mechanics to detect the rate of change of air pressure.

[0035] Specifically, when detecting the pressure change rate caused by the impact of gas in the elastic closed air chamber, ; is the rate of change of the center deformation of the substrate, which is obtained by measuring the resistance value of the resistance strain gauge; E is the elastic modulus of the substrate, Pa; h is the thickness of the substrate in meters; is the lateral dimension of the substrate in meters.

[0036] In this embodiment, the base sheet 5 is made of silicone material. The resistance strain gauges 8 on both sides of the base sheet 5 are symmetrically attached to both sides of the base sheet 5 by silicone coating technology. The base sheet 5 is rectangular in shape.

[0037] For the base sheet 5 made of silicone material, the range of the sensor can be adjusted by adjusting the hardness of the silicone base sheet 5 .

[0038] The present invention provides resistance strain gauges 8 on both sides of the substrate 5, and adopts a dual strain gauge mode to realize data compensation and verification. When measuring the resistance value, the average value of the resistance values ​​of the two resistance strain gauges 8 is used as the final output result, which makes up for the measurement error problem caused by the different deformation amounts on the upper and lower sides of the substrate 5, improves the measurement accuracy, and realizes high-precision output and data compensation.

[0039] The base sheet 5 is sandwiched between the first shell 1 and the second shell 2. The first shell 1 and the second shell 2 are connected by bolts. A sealing ring groove is provided on the side of the second shell 2 close to the base sheet 5. A sealing ring is embedded in the sealing ring groove. The base sheet 5 is in tight contact with the sealing ring.

[0040] Furthermore, the air guide channel includes a first channel section 9 arranged on the first shell 1 and a second channel section 10 arranged on the second shell 2, the first channel section 9 is connected to the second air cavity 7, the second channel section 10 is connected to the second air cavity 7, and the first channel section 9 is connected to the second channel section 10.

[0041] A through hole 13 corresponding to the air guide channel is provided on the base sheet 5 , and an O-ring 12 is provided between the base sheet 5 and the first housing 1 . The O-ring 12 is located at the periphery of the through hole 13 .

[0042] The present invention has the following advantages: 1. The sensor involved in the present invention can be applied to different types of other measurement requirements, has low requirements on gas types, and has no other electronic components except the resistance strain gauge 8 inside the sensor, and there are no semiconductor devices with high temperature requirements inside. Therefore, the present invention greatly reduces the requirements for ambient temperature during measurement, and can work in a wider temperature range, which greatly improves its applicability.

[0043] 2. The present invention has high measurement sensitivity and is particularly suitable for gas measurement needs in highly dynamic and high flow rate environments.

[0044] 3. The present invention is sturdy and durable, has low installation requirements, and can maintain normal operation in harsh environments.

[0045] 4. The present invention can not only measure the gas flow rate (flow), but also measure the pressure change rate caused by the impact of the gas in the elastic closed gas chamber, which solves the problem of single function of traditional gas flow rate (flow) meters and meets the usage requirements in some special scenarios.

[0046] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A gas flow rate-related pressure sensor, characterized in that: A first shell, a second shell, and a substrate sheet arranged between the first shell and the second shell, the substrate sheet is made of elastic material, a first air cavity is formed between the first shell and the substrate sheet, a second air cavity is formed between the second shell and the substrate sheet, and resistance strain gauges are arranged on both sides of the substrate sheet; the first air cavity is connected to the second wall through an air guide channel; an input interface is arranged on the first shell, and an output interface is arranged on the second shell; When detecting the gas flow rate, the gas to be measured is introduced from the input interface and discharged from the output interface; When detecting the pressure change rate of the gas in the elastic closed air chamber caused by the impact, the first elastic closed air chamber is connected to the input interface, and the second elastic closed air chamber is connected to the output interface; the external collision impact is received through the first elastic closed air chamber.

2. A gas flow rate-related pressure sensor according to claim 1, characterized in that: The aperture of the input interface is larger than the aperture of the output interface, and the aperture of the output interface is larger than the aperture of the air guide channel.

3. A gas flow rate-related pressure sensor according to claim 1, characterized in that: The base sheet is made of silicone material.

4. A gas flow rate-related pressure sensor according to claim 1, characterized in that: The base sheet is sandwiched between the first shell and the second shell. The first shell and the second shell are connected by bolts. A sealing ring groove is provided on one side of the second shell close to the base sheet. A sealing ring is embedded in the sealing ring groove.

5. A gas flow rate-related pressure sensor according to claim 1, characterized in that: The air guide channel includes a first channel section arranged on the first shell and a second channel section arranged on the second shell, the first channel section is connected to the second air cavity, the second channel section is connected to the second air cavity, and the first channel section is connected to the second channel section.

6. A gas flow rate-related pressure sensor according to claim, characterized in that: The base sheet is provided with a through hole corresponding to the air guide channel, an O-ring is provided between the base sheet and the first shell, and the O-ring is located at the periphery of the through hole.

7. A gas flow rate-related pressure sensor according to claim 1, characterized in that: When detecting gas flow rate, the measured gas flow rate The calculation formula is as follows: ； In the formula, is the lateral dimension of the base sheet; is the maximum deformation at the center of the substrate; the maximum deformation at the center of the substrate is obtained by measuring the resistance value of the resistance strain gauge; E is the elastic modulus of the substrate; h is the thickness of the substrate; D2 is the equivalent diameter of the actual ventilation area of ​​the first air cavity; L is the length of the first air cavity; is the density of the gas; f is the friction factor.

8. A gas flow rate-related pressure sensor according to claim 1, characterized in that: When detecting the pressure change rate of the gas in the elastic closed air chamber caused by the impact, ； is the rate of change of the center deformation of the substrate, which is obtained by measuring the resistance value of the strain gauge; E is the elastic modulus of the substrate; h is the thickness of the substrate; is the lateral dimension of the substrate.

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