Ultrasonic gas meter

Abstract

The present invention relates to an ultrasonic gas meter. It is characterized in that a flow metering module is arranged in the meter body, and the flow metering module is composed of a square flow channel and ultrasonic sensors symmetrically installed in two main and standby paths, wherein the main path metering unit is mainly used to accurately measure the flow of gas medium, and the standby path metering unit is used to diagnose the main path metering state, and the main and standby path metering units can also participate in the gas medium metering at the same time to improve repeatability and measurement accuracy, and also reduce the influence of gas medium disturbance on its metering performance; steps that rise step by step along the gas flow direction are arranged on the upper and lower sides of the rectifier, and the guide grooves on the upper wall and the bottom plate are arranged along the gas flow direction to be step-by-step descending step grooves that match the step-by-step ascending steps of the rectifier, and the number of sections and step heights of the step grooves on the upper wall and the bottom plate are the same and symmetrical, so that each section of the step is tightly clamped together after insertion.

Description

Technical Field

[0001] The invention relates to an ultrasonic gas meter. Background Art

[0002] As a clean, efficient and high-quality energy, natural gas has become the first choice for domestic energy structure. With the widespread use of natural gas, it is particularly important to achieve fair measurement for gas meters used in trade measurement for urban natural gas users. With the construction and popularization of gas transmission pipelines, gas meters have sprung up like mushrooms after rain. From mechanical to electronic, from traditional diaphragm meters to fully electronic ultrasonic gas meters, new concepts and technologies continue to emerge, and the accuracy and scope of use of various flow meters are also constantly improving. Ultrasonic meters are gradually moving from the industrial field to the household field due to their advanced technology and easy intelligence. In particular, in recent years, ultrasonic gas meters have been emerging in the gas meter market with a strong momentum. However, ultrasonic gas meters are fully electronic instruments. Generally, commercial gas meters with small and medium flow rates generally only use a pair of ultrasonic sensors, which leads to extremely high requirements for the stability of the flow field, which will affect the performance of ultrasonic gas meters. At the same time, when any ultrasonic sensor fails, it cannot be measured normally, nor can it accurately determine the fault and notify the user for maintenance, increasing the risk of trade disputes, which will bring losses to gas companies!

[0003] Currently, the flow channel structure design for household and commercial ultrasonic gas meters mostly adopts rectangular thin-sheet rectifiers, which divide the square flow channel into multiple layers of flat flow paths. In order to facilitate installation and positioning, the shape of the rectifier generally adopts protrusions protruding upwards on both ends and multiple protrusions protruding downwards on the lower end, and inserts the grooves of the flow channel bottom plate into which the protrusions on the upper side of the two sides of the rectifier are inserted. Since this installation method requires high dimensional accuracy, it is not easy to install and position, the process consistency is poor, and the production efficiency is low. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a technical solution for an ultrasonic gas meter.

[0005] The ultrasonic gas meter comprises a meter body, an air inlet and an air outlet, and is characterized in that a flow metering module is arranged in the meter body, the air inlet is connected to a control valve, the air outlet is connected to a bend, one end of the bend is connected to the air outlet, and the other end of the bend is connected to the tail of the flow metering module; the flow metering module consists of a square flow channel and two symmetrically installed main and standby ultrasonic sensors, two pairs of ultrasonic sensors are arranged at the upper and lower symmetrical center line positions of the upper wall and the bottom plate of the square flow channel, each pair of ultrasonic sensors are respectively arranged on the upper wall and the bottom plate and are radiated at a certain angle to each other, the center point of the coaxial central axis line connecting the two pairs of ultrasonic sensors intersects at the center point in the square flow channel, and the diagonal angles formed are equal.

[0006] The ultrasonic gas meter is characterized in that a plurality of symmetrically arranged guide grooves are provided on the upper wall and the bottom plate of the square flow channel along the gas flow direction, and a plurality of rectifying plates are inserted into the square flow channel from the tail of the square flow channel along the corresponding guide grooves on the upper wall and the bottom plate, thereby dividing the square flow channel into a plurality of flow paths of the same size.

[0007] The ultrasonic gas meter is characterized in that steps that gradually rise along the gas flow direction are arranged on the upper and lower sides of the rectifier, and the guide grooves on the upper wall and the bottom plate are arranged along the gas flow direction as step grooves that gradually decrease and match the step grooves that gradually rise on the rectifier.

[0008] The ultrasonic gas meter is characterized in that the inlet end of the guide groove is a step structure indented from the outside to the inside, the opening of the guide groove at the first step at the tail of the square flow channel is larger than the opening of the guide groove at the first step on the inside, and the cross-section of the opening of the last-stage guide groove near the head of the square flow channel is a bell-shaped, and the minimum spacing of the bell-shaped mouth matches the thickness of the rectifier.

[0009] The ultrasonic gas meter is characterized in that the upper and lower corners of the rectifier head are both set as arc chamfers.

[0010] The ultrasonic gas meter is characterized in that a metering circuit board is horizontally arranged at the bottom of the square flow channel, which is used to measure the flight time between multiple pairs of ultrasonic sensors and calculate the flow rate of the gas medium flowing in the square flow channel based on the measured flight time.

[0011] The ultrasonic gas meter is characterized in that the ultrasonic sensors symmetrically installed in the main and backup paths cooperate with the metering circuit board to form two independent metering units, wherein the main path metering unit is mainly used for accurately measuring the flow of the gas medium, and the backup path metering unit is used for diagnosing the main path metering status, and the main path metering unit and the backup path metering unit can also participate in the gas medium metering at the same time to improve the measurement accuracy.

[0012] The ultrasonic gas meter is characterized in that a first sealing ring and a buckle are provided between the control valve and the air inlet, and the control valve is installed at the air inlet through the buckle; the bent pipe is provided with a mounting portion, the mounting portion of the bent pipe is inserted into the tail of the flow metering module to connect them as one, and a second sealing ring is provided between the mounting portion of the bent pipe and the tail of the flow metering module, and the other end of the bent pipe is sealed and connected to the air outlet through a third sealing ring.

[0013] The ultrasonic gas meter is characterized in that fixing brackets are respectively provided on both sides of the flow metering module, and mounting holes are provided on the fixing brackets, so that the flow metering module can be fixed on the meter body by fixing screws.

[0014] The ultrasonic gas meter is characterized in that the plane formed by the connection lines of the two pairs of ultrasonic sensors is arranged horizontally; the cross-section of the square flow channel is rectangular, and the distance between the upper wall and the bottom plate of the square flow channel is greater than the distance between the two side walls of the square flow channel.

[0015] The advantages and disadvantages of the present invention compared with the existing structure are as follows:

[0016] 1. Traditional ultrasonic gas meters use a monophonic structure. The airflow disturbance of the gas medium will affect the performance of the ultrasonic gas meter. At the same time, when the ultrasonic sensor fails, it cannot measure normally, nor can it accurately determine the fault and notify the user for maintenance, increasing the risk of trade disputes, which will cause losses to the gas company;

[0017] The present invention adopts a plurality of pairs of ultrasonic sensor structures, which form a main path and a backup path ultrasonic sensor, and respectively form two independent metering units with a metering circuit board, wherein the main path metering unit is mainly used for accurately measuring the flow of the gas medium, and the backup path metering unit is used for diagnosing the metering state of the main path. The main and backup path metering units can also participate in the gas medium metering at the same time to improve repeatability and measurement accuracy, and also reduce the influence of the disturbance of the gas medium on its metering performance;

[0018] 2. In traditional ultrasonic gas meters, the flow channel structure design mostly adopts rectangular thin-sheet rectifiers, which divide the square flow channel into multiple layers of flat flow paths. In order to facilitate installation and positioning, the shape of the rectifiers generally adopts protrusions protruding upwards at both ends and multiple protrusions protruding downwards at the lower end, and the grooves on the bottom plate of the flow channel are inserted into the protrusions on the upper sides of the two sides of the rectifier. Since this installation method requires high dimensional accuracy, it is not easy to install and position, the process consistency is poor, the production efficiency is low, and the verticality of the rectifier insertion cannot be guaranteed, which will reflect the sound waves of the ultrasonic sensor, not only greatly attenuating the amplitude of the received signal, but also causing the measurement stability to deteriorate.

[0019] The square flow channel in the measurement area of ​​the present invention adopts an integral design, and steps that gradually rise along the gas flow direction are arranged on the upper and lower sides of the rectifier, and the guide grooves on the upper wall and the bottom plate are arranged along the gas flow direction as step-by-step descending step grooves that match the step-by-step ascending steps of the rectifier. The number of sections and the step heights of the step grooves on the upper wall and the bottom plate are the same and symmetrical, so that the steps are tightly clamped together after insertion, which is not only convenient for installation and positioning, but also the multi-layer thin-sheet rectifier is installed with high verticality and no looseness, which achieves the best rectification effect while greatly reducing the attenuation of the received signal amplitude, providing measurement stability;

[0020] 3. Traditional ultrasonic gas meters mostly use V-shaped reflection type, which is easy to be polluted and accumulated at the bottom, affecting the gas reflection;

[0021] The present invention adopts the method of opposite beam, even if the bottom is polluted and accumulated, it will not affect the measurement effect;

[0022] 4. Traditional ultrasonic gas meters usually place the metering circuit board horizontally on top of the metering module, which will cause pollutants in the natural gas to accumulate on the surface of the circuit board, causing corrosion of the circuit board and electrical performance failure. In particular, the pressure sensor is usually installed on the surface of the metering circuit board. This installation method makes the pressure sensor face upward, which makes it easy for natural gas dust, particles and water to enter the pressure sensor, forming pollutants on the surface, causing deviations in pressure testing;

[0023] The present invention places the metering circuit board and the pressure sensor downward, so that no pollution accumulation will occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of the ultrasonic gas meter of the present invention;

[0025] Figure 2 This is a schematic diagram of the flow metering module of the present invention;

[0026] Figure 3 It is a side view of the flow metering module of the present invention;

[0027] Figure 4 is a cross-sectional view of the flow metering module of the present invention;

[0028] Figure 5 for Figure 4 Enlarged view of part A in the middle;

[0029] Figure 6 It is a cross-sectional view of a square flow channel;

[0030] Figure 7 Schematic diagram of the rectifier;

[0031] Figure 8 This is an enlarged schematic diagram of the guide groove. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings:

[0033] The ultrasonic gas meter of the present invention comprises a meter body 21, on which an air inlet 22 of the ultrasonic gas meter, an air outlet 23 of the ultrasonic gas meter, a control valve 24, and a flow metering module 30 are arranged. The flow metering module 30 is connected to a bend 25, and the bend 25 is provided with a mounting portion 25a. The mounting portion 25a of the bend 25 is inserted into the tail of the flow metering module 30 to make the structure connected as one. A control valve 24 is arranged inside the ultrasonic gas meter 21. When the user uses gas normally, the valve is in an open valve state, and the gas flows into the ultrasonic gas meter through the control valve 24; when abnormal conditions such as gas leakage and arrears occur, the control valve 24 will be closed immediately, thereby blocking the gas from entering the ultrasonic gas meter housing. A first sealing ring 26c and a buckle mounting structure are arranged at the inlet of the control valve 24, which are connected to the air inlet 22 of the ultrasonic gas meter and are structurally integrated. The main purpose of the sealing ring 26c is to ensure that all the gas flowing through the air inlet 22 of the ultrasonic gas meter flows out into the cavity 27 of the ultrasonic gas meter through the control valve 24.

[0034] The external turbulent airflow entering the gas meter inlet enters the flow metering module 30 after being buffered by the inner cavity of the gas meter, and then undergoes multi-stage rectification by the honeycomb rectifier network 11, the Venturi rectifier 12 and the square front straight pipe 13 at the inlet end of the flow metering module 30, and then enters the test area of ​​the ultrasonic sensor group (34a-34d) after the airflow is adjusted to a laminar state by a plurality of rectifiers 38. A metering circuit board is horizontally arranged at the bottom of the square flow channel, and when the gas medium 28 flows in the pipeline, the metering circuit board in the circuit board sealing box 32 calculates the gas medium flow rate in the pipeline by using the measured propagation time difference △T between the main ultrasonic sensor group (34a, 34b) and the backup ultrasonic sensor group (34c, 34d), which is proportional to the gas medium flow rate in the pipeline. The tail portion 37 of the flow metering module is connected and sealed to the air outlet elbow 25 via a second sealing ring 26a, and the other end of the air outlet elbow 25 is connected and sealed to the ultrasonic gas meter air outlet 23 via a third sealing ring 26b. The purpose is to ensure the sealing between the outlet portion of the flow metering module 30 and the air outlet 23 of the ultrasonic gas meter, that is, to allow the gas medium flowing into the flow metering module 30 to pass through the air outlet elbow 25 and then flow out from the ultrasonic gas meter air outlet 23.

[0035] The flow metering module 30 is provided with a fixing bracket 33 on both sides, and the fixing bracket 33 is provided with two mounting holes, and the flow metering module 30 can be fixed on the meter body by two fixing screws. The purpose is to fix the flow metering module 30 and the ultrasonic gas meter body 21 into a whole, and prevent the flow metering module 30 from shaking in the shell and affecting the metering performance.

[0036] The flow metering module 30 of the present invention is mainly composed of a rectifier at the inlet end, a square flow channel, an ultrasonic sensor and a metering circuit board. The square flow channel is composed of side walls (36a, 36b) along the flow direction of the measured gas, an upper wall 36c and a corresponding bottom plate 36d. The multi-layer rectifier 38 is inserted into the square flow channel from the tail 37 of the flow metering module to divide the flow channel into a plurality of identical flat small flow channels. On the upper wall 36c of the square flow channel and the corresponding bottom plate 36d, four ultrasonic sensors 34a, 34b, 34c, 34d are respectively arranged at the central symmetrical positions of the two side walls of the square flow channel, and are respectively installed and fixed in the mounting holes 31a, 31b, 31c, 31d through mounting pressure caps 35a, 35b, 35c, 35d with locking buckle functions.

[0037] Through the installation holes with pre-set angles in the flow channel structure, the ultrasonic sensors 34a and 34b are respectively fixedly installed with the upper wall 36c and the bottom plate 36d in a coaxial opposite manner at the same angle to form an independent ultrasonic sensor group that transmits and receives each other. This opposite installation method allows the ultrasonic transceiver sensor 34a to send ultrasonic waves directly through the multi-layer rectifier 38 horizontally, and then reach the opposite ultrasonic sensor 34b to receive the ultrasonic signal, avoiding the problem of signal attenuation caused by the uneven reflection surface in the traditional reflection installation method, thereby obtaining the optimal receiving sensitivity and ensuring the stability of the metering performance. The installation surface of the ultrasonic sensor and the installation hole 31 is provided with a corrosion-resistant rubber gasket, which has two functions: 1. It can play a sealing role to prevent the gas medium flowing through the flow metering module 30 from leaking from the installation hole 31 and affecting the measurement accuracy; 2. It can serve as an effective shock-absorbing carrier, that is, it can make the ultrasonic sensor vibrate quickly after transmitting the signal to avoid affecting the signal reception, and can quickly and stably reduce the noise of the ultrasonic sensor that receives the ultrasonic signal to improve the signal-to-noise ratio, ensure the accuracy of the ultrasonic signal flight time △T, and thus improve the metering stability. The ultrasonic sensors 34c and 34d are installed in the same way, forming another pair of independent ultrasonic sensor groups that transmit and receive each other, and the plane formed by the connection of the two pairs of ultrasonic sensors is arranged horizontally. The symmetry of the two pairs of transducers is fully considered in the structural design. When the gas medium flows through the metering module, the flow measured by the two pairs of ultrasonic sensors (transducers) is the same. According to this feature, the two pairs of transducers can form the main and backup transducers, which respectively form two independent metering units with the metering circuit board. The main metering unit is mainly used for accurate metering of the gas medium flow, and the backup metering unit is used for diagnosis of the main metering status. If the main metering unit fails, the backup metering unit can be switched to continue the measurement. The main and backup metering units can also participate in the gas medium metering at the same time to improve repeatability and measurement accuracy, and also reduce the impact of gas medium disturbance on its metering performance.

[0038] A square front straight pipe is arranged at the front end of the square flow channel, a Venturi rectifier is arranged at the front end of the square front straight pipe, and a honeycomb rectifier 11 is arranged at the front end of the Venturi rectifier. The gas medium enters the square flow channel through the honeycomb rectifier 11, the Venturi rectifier 12 and the square front straight pipe 13. The turbulent gas medium 28 at the inlet end can enter the measuring area of ​​the ultrasonic sensor after being rectified at the front stage, so that the airflow in the measuring area is stable, the stability of small flow rate and the overall metering quarter are improved, and due to the large flow cross-sectional area of ​​the honeycomb rectifier, the pressure loss generated by the gas medium is extremely small.

[0039] The following is a description of the insertion of the rectifying piece 38 into the guide groove 39 in the square flow channel:

[0040] A plurality of guide grooves 39 are evenly distributed on the bottom plate 36d of the square flow channel, and the groove direction is from the tail 37 of the flow metering module to the head. A step groove 39a that descends step by step is provided at the same position of each guide groove 39, and a corresponding step 38a that ascends step by step is provided on the corresponding rectifier piece 38. After the rectifier pieces are inserted into the guide grooves, they abut against each other to fix and limit.

[0041] The entrance end of the guide groove 39 is indented from the outside to the inside, that is, the circumference of the entrance end surrounded by the first outer edge 39h, the second outer edge 39i, and the third outer edge 39j is greater than the circumference surrounded by the first inner edge 39d, the second inner edge 39e, the third inner edge 39f, and the fourth inner edge 39g, and is not in the same plane. The purpose of this design is to facilitate the easy insertion of the rectifier. Since the guide groove extends from the tail 37 of the metering module to the entrance, the stroke is very long. In order to facilitate the demolding during injection molding and avoid excessive burrs at the bottom of the guide groove that affect the insertion of the rectifier, the first inner edge 39d and the second inner edge 39e of the upper half of the guide groove are two inclined angle openings, that is, the upper part 39k of the guide groove is larger than the bottom 39c and the width of the rectifier 38. The purpose of this design is to facilitate the easy insertion of the rectifier. The lower part of the guide groove is composed of two vertical guide grooves, the third inner edge 39f and the fourth inner edge 39g and the bottom 39c, and its width is equal to the width of the rectifying piece 38. When the rectifying piece 38 is gradually inserted, it fits tightly with the inner wall of the lower part of the guide groove to fix it well, preventing the rectifying piece 38 from shaking when the gas flow is too large, resulting in unstable metering.

[0042] Since the guide groove extends from the metering module tail 37 to the entrance for a long distance, the friction force of the rectifier 38 gradually inserted into the guide groove 39 of the ultrasonic metering module tail 37 is constantly increasing, which makes it very difficult to insert during installation and reduces production efficiency. At the same time, excessive force can easily cause the rectifier 38 to bend and affect the gas flow field rectification effect. In order to solve this problem, the present invention connects the rectifier 38 and the guide groove 39

[0043] Multiple tiny steps are used to reduce insertion friction.

[0044] The rectifier 38 forms multiple symmetrical steps 38a that rise step by step along the gas flow direction. The guide groove bottom 39c in the upper wall 36c of the ultrasonic metering module and the corresponding bottom plate 36d has a step groove 39a that is gradually lowered along the gas flow direction for the above-mentioned rectifier to be inserted. The number of steps and the step height on the upper wall and the bottom plate are the same and symmetrical, so that each step is tightly clamped together after insertion. In this embodiment, three steps are selected, resulting in a 3-fold reduction in the contact area between the rectifier 38 and the guide groove bottom 39c, and the friction force during insertion is also reduced by 3 times accordingly. The entrance angle of the rectifier 38 is the narrowest end of the multi-segment rectifier 38, and the head adopts a chamfered design, the purpose of which is to avoid encountering the step blocking in the guide groove bottom 39c during insertion to facilitate insertion.

[0045] The entrance of the guide groove 39 has an inclined surface that gradually decreases from the outside to the inside for the rectifier 38 to be inserted. At the same time, the upper part 39k of the guide groove is larger than the bottom 39c and has a first inner edge 39d and a second inner edge 39e that are wider at the top and narrower at the bottom. When the rectifier 38 is first inserted from the tail part 37 of the flow channel structure, the rectifier 38 can be easily pushed into the guide groove 39 due to the gradually decreasing inclined surface at the entrance of the guide groove 39. As the rectifier 38 is gradually pushed forward, due to the action of the first inner edge 39d and the second inner edge 39e of the inner wall of the guide groove, the rectifier 38 can be easily inserted into the bottom 39c of the guide groove. When the rectifier 38 is continuously pushed toward the guide groove 39, since the front end of the rectifier is provided with a circular chamfer 38c, the width d1 of the first-stage rectifier is equal to the width L3 of the first guide groove, and is smaller than the width L2 of the first second guide groove and the width L2 of the second guide groove, the contact friction between the rectifier 38 and the guide groove 39 is greatly reduced, so that the rectifier 38 is easily inserted into the flow channel structure to reach the set position, that is, the multiple sections of small downward steps in the guide groove and the rectifier 38 are inserted into multiple sections of small downward steps along the gas flow direction, and are tightly clamped together. When the rectifier is inserted to the bottom, the step 38a of the rectifier 38 that rises step by step and the step groove 39a of the guide groove that decreases step by step are engaged with each other in sequence. Since the width of the rear step is greater than the width of the front step, the rectifier 38 cannot be pushed forward after reaching the predetermined position, that is, the tail of the rectifier 38 is on the same plane as the first outer edge 39h, the second outer edge 39i, and the third outer edge 39j of the guide groove 39. Finally, the elbow 25 is inserted into the outlet of the flow metering module 30 to make its structure integrated, and its mounting portion 25a is fitted with the tail of the rectifier 38 to prevent the rectifier 38 from withdrawing.

[0046] The flow channel structure design of the present invention is not only applicable to ultrasonic gas metering instruments, but also applicable to MEMS thermal gas flow meters.

Claims

1. An ultrasonic gas meter, comprising a meter body, an air inlet and an air outlet, characterized in that The flow metering module is arranged in the meter body, the air inlet is connected to the control valve, the air outlet is connected to the elbow, one end of the elbow is connected to the air outlet, and the other end of the elbow is connected to the tail of the flow metering module; the flow metering module is composed of a square flow channel and two symmetrically installed ultrasonic sensors, two pairs of ultrasonic sensors are arranged on the upper wall and the bottom plate of the square flow channel at the upper and lower symmetrical center line positions, each pair of ultrasonic sensors is arranged on the upper wall and the bottom plate respectively and shoots at each other at a certain angle, and the center point of the coaxial central axis line connecting the two pairs of ultrasonic sensors intersects at the center point in the square flow channel, The diagonal angles formed are equal; a plurality of symmetrically arranged guide grooves are provided on the upper wall and the bottom plate of the square flow channel along the gas flow direction, and a plurality of rectifiers are inserted into the square flow channel from the tail of the square flow channel along the corresponding guide grooves on the upper wall and the bottom plate, so as to divide the square flow channel into a plurality of flow paths of the same size; steps which gradually rise along the gas flow direction are provided on the upper and lower sides of the rectifier, and the guide grooves on the upper wall and the bottom plate are arranged along the gas flow direction as step-by-step descending step grooves which match the step-by-step ascending steps of the rectifier; the inlet end of the guide groove is a step structure which is indented from the outside to the inside, the opening of the guide groove at the first step at the tail of the square flow channel is larger than the opening of the guide groove at the first step on the inside, and the opening cross-section of the last-stage guide groove near the head of the square flow channel is a bell-shaped, and the minimum spacing of the bell-shaped matches the thickness of the rectifier.

2. An ultrasonic gas meter according to claim 1, characterized in that The upper and lower corners of the rectifier head are both set as arc chamfers.

3. An ultrasonic gas meter according to claim 1, characterized in that A metering circuit board is horizontally arranged at the bottom of the square flow channel for measuring the flight time between multiple pairs of ultrasonic sensors and calculating the flow rate of the gas medium flowing in the square flow channel according to the measured flight time.

4. An ultrasonic gas meter according to claim 3, characterized in that The symmetrically installed ultrasonic sensors on the main and backup routes cooperate with the metering circuit board to form two independent metering units, wherein the main route metering unit is used to accurately measure the flow of the gas medium, and the backup route metering unit is used to diagnose the main route metering status. The main route metering unit and the backup route metering unit can also participate in the gas medium metering at the same time to improve the measurement accuracy.

5. An ultrasonic gas meter according to claim 1, characterized in that A first sealing ring and a buckle are provided between the control valve and the air inlet, and the control valve is installed at the air inlet through the buckle; a mounting portion is provided on the bent pipe, and the mounting portion of the bent pipe is inserted into the tail of the flow metering module to connect them as one, and a second sealing ring is provided between the mounting portion of the bent pipe and the tail of the flow metering module, and the other end of the bent pipe is sealed and connected to the air outlet through a third sealing ring.

6. An ultrasonic gas meter according to claim 1, characterized in that The flow metering module is provided with fixing brackets on both sides respectively, and the fixing brackets are provided with mounting holes, and the flow metering module can be fixed on the meter body by fixing screws.

7. An ultrasonic gas meter according to claim 1, characterized in that The plane formed by the connection lines of the two pairs of ultrasonic sensors is arranged horizontally; the cross section of the square flow channel is rectangular, and the distance between the upper wall and the bottom plate of the square flow channel is greater than the distance between the two side walls of the square flow channel.

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