Gas metering device based on a mems sensor

Abstract

This invention relates to the field of gas metering technology, specifically to a gas metering device based on a MEMS sensor. The device includes a metering pipe and a sensor. The sensor is mounted on the metering pipe, and a rotating shaft is rotatably mounted on the pipe. A sphere is connected to the rotating shaft and is slidably sealed to the metering pipe. The sphere has a channel, and openings on both sides of the channel communicate with it. The sensor's axis is coaxial with the rotating shaft, and the sensor extends into the channel. A motor is mounted on the metering pipe, and the motor's output is connected to the rotating shaft. This invention increases the gas flow rate by switching between channels of different sizes connected to the gas pipe, without changing the gas flow direction. This ensures the accuracy of the gas metering device without requiring the sensor to rotate, thus avoiding the introduction of new errors.

Description

Technical Field

[0001] This invention relates to the field of gas metering technology, specifically to a gas metering device based on MEMS sensors. Background Technology

[0002] With the development of the Internet of Things, gas metering devices based on MEMS sensors have advantages such as low cost, small size, and integrability, which have enabled gas metering devices based on MEMS sensors to gradually replace traditional diaphragm gas meters and become an important technological direction in the field of smart gas metering.

[0003] However, when current MEMS gas metering devices measure gas at low gas flow rates, the thermal boundary layer of the MEMS thermal sensor cannot overcome the static gas encapsulation effect at low flow rates, and the heat of the MEMS thermal sensor cannot diffuse with the airflow, resulting in a decrease in the accuracy of gas metering.

[0004] To address this issue, patent application CN202111665334.7 provides a small-range thermal gas mass flow meter. This invention uses U-shaped tubes on both sides of the measuring pipe. When the gas flow rate decreases, the main pipe is closed, allowing the gas to enter through the U-shaped tubes and flow through the sensor. The diameter of the U-shaped tubes is much smaller than that of the main pipe, causing the airflow to accelerate upon entering the U-shaped tubes, thereby increasing the airflow speed and ensuring measurement accuracy. However, during use, the sensor usually needs to be parallel or perpendicular to the airflow. Therefore, the sensor needs to be rotated during use. This rotation causes mechanical wear, leading to loosening of the sensor rotation mechanism and introducing new measurement errors.

[0005] Therefore, in order to improve the accuracy of gas metering devices, a gas metering device based on MEMS sensors is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a gas metering device based on a MEMS sensor. In order to improve the accuracy of the gas metering device and avoid the introduction of new errors, the device connects to the gas pipeline by switching channels of different sizes. After the channel is switched, the gas flow direction does not change. This increases the gas flow rate and ensures the accuracy of the gas metering device without rotating the sensor, thereby avoiding the introduction of new errors.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A gas metering device based on a MEMS sensor includes a metering pipe and a sensor. The sensor is mounted on the metering pipe, and a rotating shaft is rotatably mounted on the metering pipe. A ball is connected to the rotating shaft and is slidably sealed to the metering pipe. A channel is opened on the ball, and openings communicating with the channel are provided on both sides of the channel. The axis of the sensor is coaxial with the rotating shaft, and the sensor extends into the interior of the channel. A motor is mounted on the metering pipe, and the output end of the motor is connected to the rotating shaft.

[0009] The sphere is rotated by a motor, connecting the inlet to the gas pipeline while closing the channel. This allows gas to flow through the inlet, which is smaller than the channel diameter. This increases the gas velocity as the gas flows in, preventing a decrease in the accuracy of the gas metering device due to low gas velocity. The direction of airflow does not change after the sphere rotates, so there is no need to rotate the sensor. This avoids the problem of the sensor becoming loose due to wear after repeated rotations, which could affect the accuracy of the gas metering device.

[0010] Preferably, a closed pipe is slidably installed at the opening, a return spring is connected between the closed pipe and the sphere, a winding cavity communicating with the opening is opened inside the sphere, a winding component is provided on the metering pipe, a pull rope is connected between the winding component and the closed pipe, the winding component is connected to a motor and a rotating shaft respectively, multiple guide rollers are provided inside the winding cavity, and the pull rope passes around the guide rollers and connects to the closed pipe.

[0011] By installing a closed pipe at the inlet and a winding device on the metering pipe, the rotation of the sphere can be achieved by the motor, ensuring the accuracy of the gas metering device. It can also drive the winding device to wind up the pull rope, thereby pulling the two closed pipes to cover the sensor. This allows the gas to flow along the closed pipe after entering the inlet, avoiding the reduction in gas flow velocity and the occurrence of turbulence due to changes in the width of the flow part, which would affect the accuracy of the gas metering device.

[0012] Preferably, the winding component includes a winding wheel, a pusher cylinder, and a power cylinder. The winding wheel is disposed on the motor output end, which extends into the winding cavity. The power cylinder is sleeved on the motor output end and slides along the axial direction of the motor output end. Power block one and power block two are respectively disposed on the power cylinder and the rotating shaft. The pusher cylinder is slidably installed on the metering pipe and is threadedly connected to the motor output end, and the pusher cylinder is rotatably connected to the power cylinder.

[0013] By installing a winding wheel at the motor output end, the rotation of the motor winds up the pull rope, thereby pulling the closed pipe towards the sensor side. This ensures the stability of gas flow and the accuracy of the gas metering device. When the motor reverses, the pull rope is released, and the reset spring pushes the closed pipe back to its original position, thus not interfering with the normal operation of the gas metering device. During motor rotation, when power block one and power block two are misaligned, the motor rotation only releases or winds up the pull rope. Therefore, during use, the closed pipe moves a set distance first, and then the sphere begins to rotate. When the sphere rotates to a set angle, the motor rotation will not drive the sphere to rotate, but it will still... By continuing to retract or release the pull rope, the gas metering device can be repositioned and embedded inside the side wall of the measuring pipe during use, thereby reducing the size of the sphere. This reduces the size of the metering device, helps save materials, and lowers manufacturing costs. After the closed pipe is embedded in the sphere, the motor rotation will drive the closed pipe to move a set distance and then drive the sphere to rotate, thus not interfering with the rotation of the sphere. After the sphere rotates to a set angle and stops rotating, the closed pipe continues to move to cover the sensor, thus preventing the sphere from rotating after the closed pipe contacts the sensor, which could damage the sensor or the seal on the closed pipe and affect the accuracy of the gas metering device.

[0014] Preferably, a sealing plate is hinged to the side wall of the metering pipe, the sealing plate has an arc surface, the arc surface has the same diameter as the inner wall of the sphere, and a pull rope is connected between the sealed pipe and the sealing plate.

[0015] By installing a sealing plate on the side wall of the metering pipe, and connecting the sealed pipe to the sealing plate with a pull rope, the sealed pipe is reset by a return spring, and the sealing plate is pulled by the pull rope to embed it into the through hole. This avoids the problem of turbulence caused by gas flowing through the sphere's inner wall, which can affect the accuracy of the gas metering device. The sealing plate has an arc surface with the same diameter as the inner wall of the sphere, ensuring the flatness of the inner wall of the sphere after the sealing plate blocks the through hole, further preventing turbulence and ensuring the accuracy of the gas metering device.

[0016] Preferably, the sealing plate has a chamfer, a slider is slidably installed on the metering pipe, the sealing plate is hinged to the slider, and there is a gap at the hinge.

[0017] The hinged sealing plate is prone to tilting, which can affect the flatness of the inner wall of the sphere. To address this, the sealing plate is hinged to the slider. The chamfered corner guides the sealing plate to fit with the opening. By setting a movable gap, the angle of the sealing plate can be adjusted when the rope pulls the sealing plate for translation, so that the sealing plate can fit completely with the opening, ensuring the flatness of the inside of the sphere. This avoids turbulence that could affect the accuracy of the gas metering device.

[0018] Preferably, a pre-tightening groove is provided on the rotating shaft, the second power block is slidably installed inside the pre-tightening groove, and pre-tightening springs are installed on both sides of the second power block together with the rotating shaft.

[0019] By sliding the second power block onto the rotating shaft and connecting the second power block to the rotating shaft with a pre-tightening spring, the first power block and the second power block come into contact and drive the rotating shaft to rotate. When the ball rotates to its limit position, the pre-tightening spring can compress the ball to ensure the seal between the ball and the metering pipe. After the ball reaches its limit position, when the first power block and the second power block come into contact, the power cylinder can still rotate with the motor output end. This avoids the motor output end from jamming or the ball from being unable to rotate to its limit position, which would cause the inlet or channel to be out of axis with the gas pipeline. This would make it easy for turbulence to occur when the gas flows into the sensor, thus affecting the accuracy of the gas metering device.

[0020] Preferably, the pull rope includes a winding rope and two pulling ropes, the two pulling ropes are connected to the winding rope, the two pulling ropes are respectively connected to both sides of the closed pipe, the connection part of the winding cavity and the opening is in the same horizontal plane as the connection part of the two pulling ropes and the closed pipe, and the winding rope is connected to the winding wheel.

[0021] By pulling the closed pipe with two ropes, the tension on the closed pipe can be balanced, thus avoiding uneven stress on the closed pipe, which could cause local wear and lead to leakage, affecting the accuracy of the gas metering device.

[0022] Preferably, the opening is conical, and the closed pipe has a conical chamfer with the same slope as the opening.

[0023] By setting the inlet to a conical shape, turbulence caused by abrupt changes in diameter at the inlet can be avoided, which would affect the accuracy of the gas metering device. The maximum diameter of the inlet is equal to the diameter of the channel, so that when the sphere switches the connection between the inlet and the gas pipeline, there will be no abrupt change in diameter at the connection point, thus avoiding turbulence caused by abrupt changes in diameter and ensuring the accuracy of the gas metering device.

[0024] Preferably, the first power block abuts against the rotating shaft, the second power block abuts against the inner wall of the power cylinder, and the first power block is provided with a guide chamfer on its upper side.

[0025] Power block one abuts against the rotating shaft, and power block two abuts against the inner wall of the power cylinder, which can play a supporting role, thereby improving the bending resistance of power block one and power block two, and improving the stability of the rotation of the rotating shaft or power cylinder, reducing the vibration of the gas metering device, and extending the service life of the gas metering device.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The ball is driven to rotate by a motor, connecting the inlet to the gas pipeline. The diameter of the inlet is smaller than the diameter of the channel, which increases the gas flow velocity after the gas flows in through the inlet. This avoids the problem of reduced accuracy of the gas metering device due to low gas velocity. After the ball rotates, the direction of airflow does not change, so there is no need to rotate the sensor. This avoids the problem of the sensor becoming loose due to wear after repeated rotation, which affects the accuracy of the gas metering device.

[0028] 2. By setting up a closed pipe at the inlet and a winding device on the metering pipe, the rotation of the sphere can be achieved by the motor, ensuring the accuracy of the gas metering device. It can also drive the winding device to wind up the pull rope, thereby pulling the two closed pipes to cover the sensor. This allows the gas to flow along the closed pipe after entering the inlet, avoiding the reduction in gas flow speed and the occurrence of turbulence due to changes in the width of the flow section, which would affect the accuracy of the gas metering device.

[0029] 3. By designing the winding mechanism, the gas metering device can be embedded inside the side wall of the measuring pipe after the closed pipe is reset during use, thereby reducing the size of the sphere and thus the volume of the metering device. This helps save materials and reduce the manufacturing cost of the gas metering device. Furthermore, after the sphere rotates to its limit angle and stops rotating, the closed pipe continues to move and cover the sensor, thus preventing the sphere from rotating after the closed pipe contacts the sensor, which could damage the sensor or the seal on the closed pipe, thereby affecting the accuracy of the gas metering device. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 for Figure 1 Partial structural sectional view;

[0032] Figure 3 for Figure 2 A partial structural cross-sectional view of the middle power block one when it moves to contact the power block two;

[0033] Figure 4 for Figure 2 Cross-sectional view of the partially enclosed pipe structure;

[0034] Figure 5 for Figure 1 A schematic diagram of the structure with the measuring pipe removed.

[0035] Figure 6 for Figure 5 Sectional view at point AA;

[0036] Figure 7 for Figure 5 Sectional view at point BB;

[0037] Figure 8 This is a schematic diagram of the structure of the slider and the sealing plate of the present invention.

[0038] In the diagram: 1. Metering pipe; 2. Sensor; 3. Rotating shaft; 4. Sphere; 41. Channel; 42. Port; 43. Rewinding chamber; 5. Motor; 51. Motor output end; 6. Enclosed pipe; 7. Return spring; 8. Rewinding component; 81. Rewinding wheel; 82. Push cylinder; 83. Power cylinder; 84. Power block one; 85. Power block two; 9. Pull rope one; 91. Rewinding rope; 92. Pull rope; 10. Guide roller; 11. Sealing plate; 111. Arc surface; 112. Chamfer; 12. Pull rope two; 13. Slider; 14. Movement gap; 15. Pre-tightening groove; 16. Pre-tightening spring; 17. Conical chamfer; 18. Guide chamfer. Detailed Implementation

[0039] Please see Figures 1 to 8 This invention provides a gas metering device based on a MEMS sensor, the technical solution of which is as follows:

[0040] A gas metering device based on a MEMS sensor includes a metering pipe 1, a sensor 2 threadedly connected to the metering pipe 1 (the sensor 2 is a MEMS smart sensor), a rotating shaft 3 rotatably mounted on the metering pipe 1, and a ball 4 connected to the rotating shaft 3. The ball 4 is slidably sealed to the metering pipe 1. A channel 41 is formed on the ball 4, and openings 42 communicating with the channel 41 are located on both sides of the ball 4. The diameter of the channel 41 is 100mm, and the diameter of the openings 42 is 10mm. The openings 42 communicate with the outside of the ball 4, and the axis of the openings 42 is perpendicular to the axis of the channel 41. The axis of the rotating shaft 3 is perpendicular to both the axis of the openings 42 and the axis of the channel 41. The line is perpendicular, and sensor 2 is coaxially set with rotating shaft 3. Sensor 2 extends into the interior of channel 41. Motor 5 is installed on metering pipe 1, and the motor output end 51 is connected to rotating shaft 3. By setting sphere 4, sensor 2 extends into the interior of sphere 4, and sensor 2 is coaxially set with rotating shaft 3. When motor 5 drives rotating shaft 3 to rotate, rotating shaft 3 drives sphere 4 to rotate, thereby connecting port 42 to gas pipe. The diameter of port 42 is smaller than the diameter of channel 41, which increases the flow velocity of gas flowing into port 42, thus ensuring the metering accuracy of gas metering device. During this process, the flow direction of gas does not change, and therefore no further action is required. Rotate sensor 2 to prevent mechanical wear from causing sensor 2 to loosen and reduce the metering accuracy of the gas metering device; a closed pipe 6 is slidably installed at the port 42, and a return spring 7 is connected between the closed pipe 6 and the ball 4. The ball 4 has a winding cavity 43 that communicates with the port 42. A winding component 8 is provided on the metering pipe 1, and a pull rope 9 is connected between the winding component 8 and the closed pipe 6. Multiple guide rollers 10 are provided inside the winding cavity 43, and the pull rope 9 passes around the guide rollers 10 and connects to the closed pipe 6; since the port 42 is connected to the channel 41, in order to avoid turbulence at the connection point due to the change in diameter, after the port 42 is switched, the flow is... The winding member 8 winds up the pull rope 9, causing the pull rope 9 to pull the closed pipe 6, so that the two closed pipes 6 cover the sensor 2. After the gas enters the inlet 42, the gas flows along the closed pipe 6, avoiding the gas flow velocity reduction and turbulence caused by the change in width, which would affect the accuracy of the gas metering device. When normal gas flow measurement is required, the pull rope 9 is released through the winding member 8. At this time, the pull rope 9 no longer pulls the closed pipe 6, and the closed pipe 6 can be reset under the elastic force of the reset spring 7, so that it will not cross the inside of the channel 41 and affect the airflow inside the channel 41, thus ensuring the accuracy of the gas metering device.The winding component 8 includes a winding wheel 81 mounted on the motor output end 51, which extends into the winding cavity 43. A power cylinder 83 is fitted onto the motor output end 51 and is keyed to the motor output end 51, allowing the power cylinder 83 to move axially. Power blocks 84 and 85 are respectively mounted on the power cylinder 83 and the rotating shaft 3. A pusher 82 is slidably mounted on the metering pipe 1, threadedly connected to the motor output end 51 and rotatably connected to the power cylinder 83. During operation, the motor 5 rotates. At this time, power block 84 is not in contact with power block 85, and the motor 5 only drives the winding wheel 81 to rotate, thereby pulling the closed pipe 6 towards the sensor 2. When motor 5 rotates, the motor output end 51 drives the push cylinder 82 to slide along the axial direction of the rotating shaft 3, thereby pushing the power cylinder 83 to move towards the rotating shaft 3. This causes power block 84 to contact power block 85, thus driving the rotating shaft 3 to rotate and achieving the switching of the port 42. After the port 42 is switched, motor 5 continues to rotate. At this time, power block 84 and power block 85 separate. Then, motor 5 continues to rotate and rewinds the pull rope 9, so that the two closed pipes 6 fit together and cover the sensor 2. This prevents the ball 4 from rotating after the closed pipe 6 contacts the sensor 2, which could damage the sensor 2 or the seal on the closed pipe 6, thus affecting the accuracy of the gas metering device. In the initial stage of motor 5 rotation, power block 84... 4. When the power block 85 is not in contact, the rotating shaft 3 does not rotate, and the winding wheel 81 rotates. At this time, the winding wheel 81 first winds up the pull rope 9, so that the closed pipe 6 moves a certain distance on the ball 4 before driving the rotating shaft 3 to rotate. Therefore, the closed pipe 6 can be embedded inside the measuring pipe, and will not interfere with the rotation of the ball 4 when switching the port 42, thereby reducing the size of the ball 4 and thus reducing the size of the metering device, which helps to save materials and reduce the manufacturing cost of the gas metering device. The rotating shaft 3 is provided with a pre-tightening groove 15, and the power block 85 is slidably installed in the pre-tightening groove 15. Both sides of the power block 85 are equipped with pre-tightening springs 16 together with the rotating shaft 3. When the power block 84 pushes the rotating shaft 3 to rotate, when the ball 4 rotates to the limit position When the power block 84 is in place, it presses against the power block 85, causing the power block 85 to slide along the pre-tightening groove 15. When the ball 4 rotates to its limit position, the pre-tightening spring 16 can press against the ball 4 to ensure the sealing between the ball 4 and the metering pipe 1. After the ball 4 reaches its limit position, the power cylinder 83 can still rotate with the motor output end 51 to avoid the motor output end 51 from jamming or the ball 4 from not being able to rotate to its limit position, which would cause the port 42 or channel 41 to be out of axis with the gas pipe. This would cause turbulence when the gas flows into the sensor 2, which would affect the accuracy of the gas metering device. The power block 84 abuts against the rotating shaft 3, and the power block 85 abuts against the inner wall of the power cylinder 83. A guide chamfer 18 is provided above the power block 84.Power block 1 84 abuts against the rotating shaft 3, and power block 2 85 abuts against the inner wall of the power cylinder 83, providing support and thus improving the bending resistance of power block 1 84 and power block 2 85. This also improves the stability of the rotation of the rotating shaft 3 or the power cylinder 83, reduces vibration of the gas metering device, and extends its service life. Pull rope 1 9 includes one winding rope 91 and two pulling ropes 92. The two pulling ropes 92 are connected to the winding rope 91, which is connected to the winding wheel 81. The two pulling ropes 92 are respectively connected to both sides of the closed pipe 6. The connection point between the winding cavity 43 and the opening 42 is on the same horizontal plane as the connection point between the two pulling ropes 92 and the closed pipe 6. By making the connection point between the winding cavity 43 and the opening 42 on the same horizontal plane as the connection point between the two pulling ropes 92 and the closed pipe 6, the two pulling ropes 92... The tension in the closed pipe 6 is parallel to the axis of the closed pipe 6, thereby reducing the friction between the closed pipe 6 and the inner wall of the opening 42. This slows down the wear of the closed pipe 6 and prevents localized wear due to uneven stress, thus effectively improving the service life of the metering device. The opening 42 is conical, and the closed pipe 6 has a conical chamfer 17 with the same slope as the opening 42. The maximum diameter of the opening 42 is equal to the diameter of the channel 41. By making the opening 42 conical, turbulence caused by a sudden change in diameter at the opening 42 can be avoided, which would affect the accuracy of the gas metering device. The fact that the maximum diameter of the opening 42 is equal to the diameter of the channel 41 ensures that when the ball 4 switches between the opening 42 and the gas pipeline, there will be no sudden change in diameter at the connection point, thus avoiding turbulence caused by a sudden change in diameter and ensuring the accuracy of the gas metering device.

[0041] A slider 13 is slidably mounted on the metering pipe 1. The sealing plate 11 is hinged to the slider 13. A pull rope 12 connects the closed pipe 6 and the sealing plate 11. When the closed pipe 6 moves towards the sensor 2, the pull rope 12 is released. At this time, the pull rope 12 will not pull the sealing plate 11. The movement of the closed pipe 6 compresses the sealing plate 11, causing the slider 13 to move. When the sealing plate 11 moves out of the opening 42, the sealing plate 11 rotates. At this time, the sealing plate 11 will not interfere with the movement of the closed pipe 6. When the closed pipe 6 is reset by the spring force of the return spring 7, the closed pipe 6 pulls the sealing plate 11 to rotate, and then pulls the sealing plate 11 to slide, so that the arc surface 111 completely matches the inside of the sphere 4. This ensures the flatness of the inner wall of the sphere 4, preventing depressions that could cause turbulence and affect the accuracy of the gas metering device. The sealing plate 11 has a chamfer 112, and the hinged joint between the slider 13 and the sealing plate 11 has a movable gap 14. The chamfer 112 guides the sealing plate 11 to engage with the opening 42. The movable gap 14 allows adjustment of the sealing plate 11's angle when pulled by the rope, ensuring complete engagement with the opening 42 and maintaining the flatness of the sphere 4's interior. This prevents turbulence from affecting the accuracy of the gas metering device.

[0042] Working principle: When the gas flow rate is low, motor 5 rotates forward. At this time, the motor output end 51 drives the winding wheel 81 to rotate, and drives the pusher 82 to move towards the sphere 4. At this time, the winding wheel 81 winds up the pull rope 9, causing the pull rope 92 to pull the closed pipe 6 towards the sensor 2. When the closed pipe 6 moves, the pull rope 12 is released, and the closed pipe 6 squeezes the sealing plate 11, causing the sealing plate 11 to slide and then rotate, so that the sealing plate 11 will not interfere with the movement of the closed pipe 6. When pushing and moving, the pusher 82 pushes the power cylinder 83 to move. When the power block 84 moves to fit with the power block 85, the power block 84 squeezes the power block 85, thereby pushing the rotating shaft 3 to rotate, causing the sphere 4 to rotate. When the inlet 42 is connected to the gas pipeline, the rotation of the ball 4 is restricted when the ball 4 rotates 90°. At this time, the first power block 84 squeezes the second power block 85, causing the second power block 85 to slide along the pre-tightening groove 15 and compress the pre-tightening spring 16. At this time, the power cylinder 83 can still rotate. As the push cylinder 82 moves, the first power block 84 moves above the second power block 85. At this time, the first power block 84 no longer squeezes the second power block 85, so it will not interfere with the rotation of the motor output end 51. At this time, the winding wheel 81 continues to rotate and continuously winds up the first rope 9, so that the two closed pipes 6 fit together and cover the sensor 2. At this time, the airflow enters the closed pipe 6 along the inlet 42, thereby increasing the airflow velocity and ensuring the measurement accuracy of the metering device.

[0043] When the gas flow rate increases again, motor 5 reverses, and pull rope 9 is released. At this time, pull rope 9 no longer pulls the closed pipe 6, and the closed pipe 6 is reset under the elastic force of the return spring 7. The motor output end 51 drives the push cylinder 82 to move towards motor 5. At this time, power block 84 moves downward. When power block 84 and power block 85 are in contact, power block 84 squeezes power block 85, thereby pushing the rotating shaft 3 to rotate. The rotation drives the ball 4 to rotate, thereby connecting the channel 41 with the gas pipeline. When the ball 4 rotates 90°, the rotation of the ball 4 is restricted. At this time, power block 84 squeezes power block 85, causing power block 85 to slide along the pre-tightening groove 15 and compress the pre-tightening spring 16. At this time, the power cylinder 83 can still rotate. With the movement of push cylinder 82... Power block 1 84 moves below power block 2 85. At this time, power block 1 84 no longer squeezes power block 2 85, thus not interfering with the rotation of motor output end 51. At this time, take-up wheel 81 continues to rotate and continuously releases pull rope 1 9, so that the two closed pipes 6 are embedded into the measuring pipe. At this time, the airflow enters the gas pipe along channel 41, thus ensuring the gas supply. During the movement of closed pipe 6, closed pipe 6 pulls the sealing plate 11 through pull rope 2 12, causing the sealing plate 11 to rotate first, and then pull the sealing plate 11 to slide, so that the arc surface 111 is completely matched with the inside of the ball 4, thus ensuring the flatness of the inner wall of the ball 4, thereby avoiding the appearance of depressions in the inner wall of the ball 4, thus avoiding the problem that the gas flow through the depression is prone to turbulence and affects the measurement accuracy of the gas metering device.

[0044] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A gas metering device based on a MEMS sensor, characterized in that, The device includes a metering pipe (1) and a sensor (2). The sensor (2) is installed on the metering pipe (1). A rotating shaft (3) is rotatably installed on the metering pipe (1). A ball (4) is connected to the rotating shaft (3). The ball (4) is slidably sealed to the metering pipe (1). A channel (41) is opened on the ball (4). The ball (4) has openings (42) on both sides of the channel (41) that communicate with the channel (41). The axis of the sensor (2) is coaxial with the rotating shaft (3). The sensor (2) extends into the inside of the channel (41). A motor (5) is installed on the metering pipe (1). The output end (51) of the motor is connected to the rotating shaft (3). A closed pipe (6) is slidably installed at the opening (42). A return spring (7) is connected between the closed pipe (6) and the ball (4). A winding cavity (43) communicating with the opening (42) is opened inside the ball (4). A winding component (8) is provided on the metering pipe (1). A pull rope (9) is connected between the winding component (8) and the closed pipe (6). The winding component (8) is connected to the motor (5) and the rotating shaft (3) respectively. Multiple guide rollers (10) are provided inside the winding cavity (43). The pull rope (9) passes around the guide rollers (10) and connects to the closed pipe (6). A sealing plate (11) is hinged to the side wall of the metering pipe (1). The sealing plate (11) has an arc surface (111) on it. The arc surface (111) is equal to the diameter of the inner wall of the sphere (4). A pull rope (12) is connected between the closed pipe (6) and the sealing plate (11). The winding component (8) includes a winding wheel (81), a pusher (82), and a power cylinder (83). The winding wheel (81) is mounted on the motor output end (51), which extends into the winding cavity (43). The power cylinder (83) is sleeved on the motor output end (51) and slides along the axial direction of the motor output end (51). The power cylinder (83) and the rotating shaft (3) are respectively provided with a power block one (84) and a power block two (85). The pusher (82) is slidably mounted on the metering pipe (1). The pusher (82) is threadedly connected to the motor output end (51), and the pusher (82) is rotatably connected to the power cylinder (83).

2. The gas metering device based on a MEMS sensor according to claim 1, characterized in that, The sealing plate (11) is provided with a straight chamfer (112), and a slider (13) is slidably installed on the metering pipe (1). The sealing plate (11) and the slider (13) are hinged together, and there is a movable gap (14) at the hinged part.

3. A gas metering device based on a MEMS sensor according to claim 1, characterized in that, The rotating shaft (3) is provided with a pre-tightening groove (15), and the second power block (85) is slidably installed inside the pre-tightening groove (15). Both sides of the second power block (85) are equipped with pre-tightening springs (16) together with the rotating shaft (3).

4. A gas metering device based on a MEMS sensor according to claim 1, characterized in that, The pull rope (9) includes a winding rope (91) and two pull ropes (92). The two pull ropes (92) are connected to the winding rope (91). The two pull ropes (92) are respectively connected to both sides of the closed pipe (6). The connection part of the winding cavity (43) and the opening (42) is in the same horizontal plane as the connection part of the two pull ropes (92) and the closed pipe (6). The winding rope (91) is connected to the winding wheel (81).

5. A gas metering device based on a MEMS sensor according to claim 1, characterized in that, The opening (42) is conical in shape, and the closed pipe (6) is provided with a conical chamfer (17) with the same slope as the opening (42). The maximum diameter of the opening (42) is equal to the diameter of the channel (41).

6. A gas metering device based on a MEMS sensor according to claim 1, characterized in that, The first power block (84) abuts against the rotating shaft (3), the second power block (85) abuts against the inner wall of the power cylinder (83), and a guide chamfer (18) is provided above the first power block (84).

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