A clamp-on ultrasonic gas flow meter

Abstract

The present application relates to a clamp-on ultrasonic gas flowmeter, which belongs to the technical field of gas flowmeters. The ultrasonic flowmeter comprises an ultrasonic absorber and a pair of ultrasonic generators, each mounted on a gas delivery pipeline. A support frame is mounted on the ultrasonic absorber, a limiter is mounted on the support frame, the ultrasonic generator is mounted within the limiter, and a data processor is mounted on the support frame, with the data processor and the ultrasonic generator being electrically connected. The ultrasonic generator is used to transmit and receive ultrasonic waves. The ultrasonic generator comprises a sonic wedge, an ultrasonic transducer is clamped onto the sonic wedge, a pressure plate is mounted on the sonic wedge, the pressure plate is used to lock the ultrasonic transducer to the sonic wedge, and an isolation layer is provided between the pressure plate and the ultrasonic transducer. A housing is mounted on the outer side of the pressure plate, and the space between the housing, the pressure plate, and the ultrasonic transducer is filled with silicone. The sonic wedge abuts the gas delivery pipeline. The present application has the effect of improving the sensitivity of the ultrasonic gas flowmeter.

Description

Technical Field

[0001] The present application relates to the technical field of gas flow meters, and in particular to an external clamp-on ultrasonic gas flow meter. Background Art

[0002] Gas flow meters are commonly used measuring instruments in the gas transportation process and are often used in scenarios such as natural gas transportation, industrial gas monitoring, and corrosive gas detection. By installing a pair of ultrasonic gas flow meters on the transportation pipeline, the gas flow velocity is determined by emitting and receiving ultrasonic waves, and the gas flow rate is calculated based on the flow velocity. The patent with publication (announcement) number: CN105408726A discloses "Ultrasonic flow meters and ultrasonic absorbers for ultrasonic flow meters". By adding absorbers to the pipeline, the excess sound waves of the sound wave transceiver module are absorbed by the vibration of the ultrasonic frequency band, reducing the attenuation during the ultrasonic transmission process; thereby suppressing the long-term deformation of the ultrasonic absorber (shock-absorbing material) covering the piping, so the reduction in the shock-absorbing performance of the ultrasonic absorber relative to the piping transmission wave is suppressed. Since the ultrasonic absorber covering the piping is less deformed, the SN ratio of the ultrasonic flowmeter is prevented from decreasing over time, thereby improving the detection accuracy of the flowmeter. However, when the ultrasonic transceiver generates ultrasonic waves, the ultrasonic waves will be emitted in multiple directions. The waves in other directions cannot be weakened or eliminated, and they return to the transmission pipeline after reflection and refraction, generating a large amount of interference waves, which affects the sensitivity of the detection. Summary of the Invention

[0003] The purpose of this application is to provide an external clamp-on ultrasonic gas flowmeter to solve the technical problem that "the reduction of the SN ratio during the generation of ultrasonic waves cannot be prevented".

[0004] The present application provides an external clamp-on ultrasonic gas flow meter that adopts the following technical solution: an external clamp-on ultrasonic gas flow meter includes an ultrasonic absorber and a pair of ultrasonic generators that are sleeved on a gas delivery pipeline, a support frame is installed on the ultrasonic absorber, a limit piece is installed on the support frame, the ultrasonic generator is installed in the limit piece, a data processor is installed on the support frame, and the data processor is electrically connected to the ultrasonic generator; the ultrasonic generator is used to transmit and receive ultrasonic waves; the ultrasonic generator includes an acoustic wedge An ultrasonic transducer is clamped on the sonic wedge, and a pressing plate is installed on the sonic wedge. The pressing plate is used to lock the ultrasonic transducer on the sonic wedge, and an isolation layer is provided between the pressing plate and the ultrasonic transducer; a shell is provided on the outer side of the pressing plate, and silicone is filled between the shell, the pressing plate and the ultrasonic transducer; the sonic wedge is in contact with the gas delivery pipe; the ultrasonic wave generated by the ultrasonic generator passes through the gas delivery pipe at an angle, and the ultrasonic wave is reflected after contacting the inner wall of the gas delivery pipe and then passes through the gas delivery pipe again to be received by another ultrasonic generator.

[0005] Optionally, the ultrasonic generator is located on the same side of the gas delivery pipeline, and the ultrasonic waves emitted by the ultrasonic generator are reflected by the module in the delivery pipeline.

[0006] Optionally, the acoustic wedge includes a base plate, a wedge-shaped body is fixed on the upper side of the base plate, and an ultrasonic transmission protrusion is fixed on the lower side of the base plate, the ultrasonic transmission protrusion is pressed on the ultrasonic absorber, and the ultrasonic transmission protrusion is a wedge-shaped structure with a larger upper part and a smaller lower part; the acoustic wedge is an integral structure; the wedge-shaped body includes an inclined surface a and an inclined surface b, and limiting protrusions for limiting the pressing plate and the ultrasonic transducer are fixed on both sides of the inclined surface a, and a limiting strip for limiting the pressing plate is provided at one end of the base plate close to the inclined surface a, and a limiting hole is provided on the limiting strip; a locking platform is fixed on the inclined surface b, and the pressing plate is locked on the locking platform by screws; a snap-in groove is provided on the locking platform, and a spherical groove is provided on the inclined surface b, and the spherical groove is used to eliminate ultrasonic diffuse reflection; a triangular structure is formed between the inclined surface a, the inclined surface b and the base plate; the angle between the inclined surface b and the base plate is 49°-53°.

[0007] Optionally, the material of the sonic wedge is polyarylsulfone (PASF) material, and the sonic wedge is cut by a CNC machine tool.

[0008] Optionally, the clamping plate is a Z-shaped structure, and a limiting column is fixed at the end where the clamping plate is connected to the limiting bar, and the limiting column is clamped in the limiting hole. A connecting plate is fixed at the end where the clamping plate is connected to the locking platform, and a plug-in protrusion is fixed on the lower side of the connecting plate, and the plug-in protrusion is inserted into the clamping groove; clamping limiting plates are fixed on both sides of the clamping plate; and the clamping limiting plates are clamped on both sides of the limiting protrusion.

[0009] Optionally, the shell includes an ultrasonic vibration chamber and an ultrasonic divergence chamber, and a clamping groove is provided on the lower side of the shell; the bottom plate is embedded in the clamping groove, and a wire lead-out groove is provided on the side of the ultrasonic vibration chamber close to the ultrasonic divergence chamber, and the bottom of the ultrasonic divergence chamber is an arc-shaped structure; a pressing platform is provided on the lower side of the shell; the clamping groove is provided on the lower side of the pressing platform.

[0010] Optionally, a pair of clamps are installed on the support frame, a center groove is provided on the support frame, the limit member is locked in the center groove, a threaded hole is provided on the support frame, and the limit member is threadedly connected to the threaded hole by a bolt and locked on the support frame.

[0011] Optionally, the limit member includes a pressing member, a locking plate is installed on the lower side of the pressing member, and a sealing plate is installed on the upper side of the pressing member; a pair of mounting grooves are provided on the pressing member, a clamping groove is provided on the lower side of the mounting groove, the clamping platform is clamped in the clamping groove, and the locking plate is locked to the bottom of the pressing member by multiple screws; locking holes are provided on both sides of the pressing member; the bolts pass through the locking holes to lock the limit member to the support frame; a plurality of isolation grooves are provided on the pressing member, and the isolation grooves are arranged around the mounting grooves, and the isolation grooves are used to reduce mutual interference between ultrasonic waves.

[0012] Optionally, the ultrasonic transducer includes multiple piezoelectric ceramic sheets; the piezoelectric ceramic sheets form a matrix structure, the piezoelectric ceramic sheets include a piezoelectric ceramic layer, and electrode sheets are arranged on the upper and lower sides of the piezoelectric ceramic layer; the electrode sheets are connected by conductive sheets, and the thickness of the conductive sheets is less than the thickness of the electrode sheets.

[0013] Optionally, the data processor includes a switching module, a sending circuit module, a receiving circuit module, a data processing module, a data storage module, a timing module, a pressure monitoring module, an input and output module and a temperature monitoring module; the switching module is electrically connected to the ultrasonic generator, the switching module is electrically connected to the sending circuit module, the switching module is electrically connected to the receiving circuit module, the sending circuit module and the receiving circuit module are electrically connected to the data processing module, the data storage module, the timing module, the pressure monitoring module and the input and output module are electrically connected to the data processing module; the input and output module is connected to the display screen; and the temperature monitoring module is connected to the data processing module.

[0014] In summary, this application includes at least one of the following beneficial technical effects:

[0015] 1. During the operation of the ultrasonic flowmeter, the ultrasonic absorber is put on the gas transmission pipe, and a pair of ultrasonic generators are symmetrically fixed on the gas transmission pipe. The ultrasonic generator passes through the ultrasonic absorber and fits against the outer wall of the gas transmission pipe. The ultrasonic wave generated by the ultrasonic generator passes through the gas transmission pipe and enters the gas transmission pipe. The ultrasonic wave contacts the inner wall of the gas transmission pipe and is reflected. The ultrasonic wave passes through the gas transmission pipe again and is received by another ultrasonic generator. The waves generated by the two ultrasonic generators are superimposed. When the gas flows in the gas transmission pipe, the sound wave produces a phase difference due to the flow of the medium. The gas flow rate can be judged by the size of the phase difference, and the gas flow rate can be calculated based on the gas density, the cross-sectional area of ​​the transmission pipe and the flow time. By reflecting the ultrasonic wave in the gas transmission pipe, the propagation distance of the ultrasonic wave in the gas transmission pipe is increased, and the distance the ultrasonic wave passes through the gas medium is increased, so that more gas can be monitored, thereby improving the sensitivity of gas monitoring, so that the gas flow can be monitored under normal pressure.

[0016] 2. The compression plate locks the ultrasonic transducer on the sonic wedge, so that the ultrasonic wave generated by the ultrasonic transducer is applied to the sonic wedge, and the sonic wedge and the gas delivery pipeline are abutted against each other, and the ultrasonic wave is input into the gas delivery pipeline. An isolation layer is provided between the compression plate and the ultrasonic transducer to absorb the reverse wave, which can reduce the generation of clutter, thereby reducing the interference caused by clutter, thereby improving the sensitivity and accuracy of monitoring.

[0017] 3. Silicone is filled between the shell, the pressing plate and the ultrasonic transducer. The silicone absorbs ultrasonic waves in other directions and weakens them, thereby further reducing the interference of clutter.

[0018] 4. The ultrasonic absorber can absorb the noise in the environment and the reflected ultrasonic waves, reduce the interference of clutter, and improve the sensitivity and accuracy of gas flow monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the structure of the ultrasonic generator according to an embodiment of the present application;

[0021] Figure 3 Schematic diagram of the acoustic wedge structure according to an embodiment of the present application;

[0022] Figure 4 This is a schematic diagram of the compression plate structure of an embodiment of the present application;

[0023] Figure 5 This is a schematic diagram of the upper structure of the housing according to an embodiment of the present application;

[0024] Figure 6 This is a schematic diagram of the lower structure of the housing according to an embodiment of the present application;

[0025] Figure 7 This is a schematic diagram of the support structure of an embodiment of the present application;

[0026] Figure 8 This is a schematic diagram of the overall structure of the limiter in the embodiment of the present application

[0027] Figure 9 Schematic diagram of the structure of the pressing member and the sound wedge according to an embodiment of the present application;

[0028] Figure 10 This is a schematic diagram of the upper structure of the lower pressing member according to an embodiment of the present application;

[0029] Figure 11 This is a schematic diagram of the lower structure of the lower pressing member according to an embodiment of the present application;

[0030] Figure 12 This is a schematic diagram of the structure of an ultrasonic transducer according to an embodiment of the present application;

[0031] Figure 13 This is an oscilloscope waveform diagram of the embodiment of the present application at a pressure of 100KPA;

[0032] Figure 14 It is a schematic diagram of the principle structure of the data processor according to an embodiment of the present application.

[0033] In the figure, 1, ultrasonic absorber; 2, ultrasonic generator; 21, sonic wedge; 211, bottom plate; 212, wedge-shaped body; 213, ultrasonic transmission protrusion; 214, limiting protrusion; 215, limiting strip; 216, limiting hole; 217, locking platform; 218, snap-fit ​​groove; 219, spherical groove; 22, ultrasonic transducer; 221, piezoelectric ceramic sheet; 222, piezoelectric ceramic layer; 223, electrode sheet; 224, conductive sheet; 23, pressing plate; 231, limiting column; 232, connecting plate; 233, plug-in protrusion; 234, pressing limiting plate; 24, isolation layer; 25, shell; 251, ultrasonic vibration chamber; 25 2. Ultrasonic divergence cavity; 253. Clamping groove; 254. Wire lead-out groove; 255. Pressing platform; 3. Limiting piece; 31. Pressing piece; 32. Locking plate; 321. Positioning groove; 33. Sealing plate; 34. Mounting groove; 35. Locking hole; 36. Isolation groove; 4. Data processor; 41. Switching module; 42. Transmitting circuit module; 43. Receiving circuit module; 44. Data processing module; 45. Data storage module; 46. Timing module; 47. Pressure monitoring module; 48. Input / output module; 49. Temperature monitoring module; 5. Support frame; 51. Clamp; 52. Center groove; 53. Threaded hole; 54. Bolt. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1 -Attached Figure 14 , further details of this application are given.

[0035] Reference Figure 1 、 Figure 2 、 Figure 3 An external clamp-on ultrasonic gas flowmeter comprises an ultrasonic absorber 1 and a pair of ultrasonic generators 2, which are sleeved on a gas delivery pipe. A support frame 5 is mounted on the ultrasonic absorber 1, a limiter 3 is mounted on the support frame 5, the ultrasonic generator 2 is mounted in the limiter 3, a data processor 4 is mounted on the support frame 5, and the data processor 4 is electrically connected to the ultrasonic generator 2; the ultrasonic generator 2 is used to transmit and receive ultrasonic waves; the ultrasonic generator 2 comprises a sonic wedge 21, an ultrasonic transducer 22 is clamped on the sonic wedge 21, and the sonic wedge 21 is electrically connected to the ultrasonic generator 2. A compression plate 23 is mounted on the top, which is used to lock the ultrasonic transducer 22 onto the sonic wedge 21. An isolation layer 24 is provided between the compression plate 23 and the ultrasonic transducer 22. A housing 25 is provided on the outside of the compression plate 23, and silicone is filled between the housing 25, the compression plate 23, and the ultrasonic transducer 22. The sonic wedge 21 abuts against the gas delivery pipe. The ultrasonic wave generated by the ultrasonic generator 2 passes through the gas delivery pipe at an angle. After contacting the inner wall of the gas delivery pipe, the ultrasonic wave is reflected and passes through the gas delivery pipe again before being received by the other ultrasonic generator 2.

[0036] During the installation of the external clamp-on ultrasonic gas flowmeter, the ultrasonic absorber 1 is first sleeved on the outside of the gas delivery pipe, and then the support frame 5 is fixed to the outside of the ultrasonic absorber. A pair of assembled ultrasonic generators 2 are installed on the limiter 3. Two openings are opened on the ultrasonic absorber 1 according to the position of the ultrasonic generator 2, and the limiter 3 is locked on the support frame 5. The limiter 3 generates a pressing force on the ultrasonic generator 2 so that the lower side of the sonic wedge 21 of the ultrasonic generator 2 abuts against the gas delivery pipe, so that the ultrasonic wave generated by the ultrasonic transducer 22 can better pass through the gas delivery pipe and propagate inside the gas delivery pipe; according to the refractive index of the gas delivery pipe material and the ultrasonic The wavelength of the wave is used to calculate the angle at which the ultrasonic wave approaches total reflection, and the ultrasonic wave is input at a certain tilt angle so that the ultrasonic wave is reflected in the gas delivery pipe. The two sets of ultrasonic waves interfere with each other in the gas delivery pipe. When the gas flows, a phase difference is generated between the two sets of ultrasonic waves. The speed of the gas flow is determined based on the size of the phase difference, and the corresponding gas flow rate can be determined based on the gas density, gas pressure, and cross-sectional area of ​​the gas delivery pipe. When the ultrasonic wave passes through the gas delivery pipe again and is received by the ultrasonic generator 2, the transmission distance of the ultrasonic wave in the gas delivery pipe is increased, the length of the ultrasonic wave passing through the gas is increased, more gas is monitored, and the sensitivity of the gas flow meter is improved.

[0037] The ultrasonic generator 2 converts the electrical signal into an ultrasonic signal after the ultrasonic transducer 22 is energized. The pressing plate 23 presses the ultrasonic transducer 22 onto the sonic wedge 21, so that the ultrasonic transducer 22 and the sonic wedge 21 are tightly fitted together, thereby improving the coupling effect between the ultrasonic transducer 22 and the sonic wedge 21. The ultrasonic wave generated by the ultrasonic transducer 22 is applied to the sonic wedge 21, and the sonic wedge 21 is in close contact with the gas delivery pipe, so that the ultrasonic wave passes through the gas delivery pipe and propagates in the gas delivery pipe. When the ultrasonic wave is reflected and passes through the gas delivery pipe again and contacts the sonic wedge 21, the wave signal is converted into an electrical signal by the ultrasonic transducer 22, thereby obtaining a waveform diagram and a phase difference caused by the gas flow, thereby knowing the gas flow rate.

[0038] An isolation layer 24 is provided between the pressing plate 23 and the ultrasonic transducer 22. The isolation layer 24 can absorb the ultrasonic waves between the ultrasonic transducer 22 and the pressing plate 23, thereby reducing the intensity of the ultrasonic waves transmitted in the reverse direction and thus reducing the interference of clutter.

[0039] Silicone is filled between the shell 25, the pressing plate 23 and the ultrasonic transducer 22. Filling with silicone can increase the stability of the connection between the shell 25, the pressing plate 23 and the ultrasonic transducer 22, and absorb ultrasonic waves transmitted in other directions, thereby further reducing the interference of clutter.

[0040] In order to further improve the sensitivity of ultrasonic gas flowmeter detection, the material of the sonic wedge 21 is polyarylsulfone (PASF), which is cut by CNC machine tools. Polyarylsulfone (PASF) has good tensile strength, bending strength and hardness, and can still maintain good mechanical properties at high temperatures. The ultrasonic transducer 22 is pressed against the sonic wedge 21, and then the sonic wedge 21 is pressed against the gas transmission pipeline (metal pipeline, natural gas transmission mainly uses metal pipelines), so that the ultrasonic wave can be better coupled between the ultrasonic transducer 22, the sonic wedge 21 and the gas transmission pipeline, thereby reducing the energy loss during wave propagation and improving the stability of wave propagation, thereby improving the sensitivity of ultrasonic gas flowmeter detection and enabling ultrasonic gas flow to monitor gas flow under normal pressure;

[0041] Reference Figure 1 、 Figure 2 、 Figure 3 The ultrasonic generator 2 is located on the same side of the gas delivery pipeline. The ultrasonic wave emitted by the ultrasonic generator 2 is reflected inside the delivery pipeline. The ultrasonic wave generated by the ultrasonic generator 2 passes through the gas delivery pipeline at an angle and contacts the gas delivery pipeline, and is reflected and received by another ultrasonic generator 2. As a result, the two groups of ultrasonic waves interfere with each other. When the gas flows in the gas delivery pipeline, a phase difference is generated between the two groups of ultrasonic waves, and the gas flow rate is judged according to the size of the phase difference.

[0042] Reference Figure 2 、 Figure 3 The acoustic wedge 21 includes a bottom plate 211, a wedge-shaped body 212 is fixed on the upper side of the bottom plate 211, and an ultrasonic transmission protrusion 213 is fixed on the lower side of the bottom plate 211. The ultrasonic transmission protrusion 213 is pressed against the ultrasonic absorber 1, and the ultrasonic transmission protrusion 213 is a wedge-shaped structure with a larger upper portion and a smaller lower portion; the acoustic wedge 21 is an integral structure; the wedge-shaped body 212 includes an inclined surface a and an inclined surface b, and limiting protrusions 214 for limiting the clamping and pressing plate 23 and the ultrasonic transducer 22 are fixed on both sides of the inclined surface a, and the bottom plate 211 is close to the inclined surface A limiting strip 215 for limiting the clamping of the clamping plate 23 is provided at one end of a, and a limiting hole 216 is provided on the limiting strip 215; a locking platform 217 is fixed on the inclined surface b, and the clamping plate 23 is locked on the locking platform 217 by screws; a clamping groove 218 is provided on the locking platform 217, and a triangular structure is formed between the inclined surface a, the inclined surface b and the bottom plate 211; the angle between the inclined surface b and the bottom plate 211 is 49°-53°. Different specifications of wedge-shaped bodies 212 are selected according to gas delivery pipelines of different diameters.

[0043] The ultrasonic transducer 22 is clamped between the limiting protrusions 214, and the isolation layer 24 is attached to the side of the ultrasonic transducer 22 away from the inclined surface a. The pressing plate 23 is locked to the acoustic wedge 21. The ultrasonic wave generated by the ultrasonic transducer 22 is input through the inclined surface a and output through the inclined surface b and the ultrasonic transmission protrusion 213 on the bottom plate 211. The ultrasonic transmission protrusion 213 is in contact with the gas transmission pipeline, and the ultrasonic wave outputted by the ultrasonic transmission protrusion 213 can be concentrated on the ultrasonic transmission protrusion 213, thereby concentrating multiple groups of ultrasonic waves together and improving the ultrasonic penetration ability.

[0044] Spherical grooves 219 are provided on the inclined surface b to eliminate diffuse reflection of ultrasonic waves. When ultrasonic waves pass through the inclined surface b, they pass from a medium with high density into a medium with low density. Refracted by the spherical grooves 219, the ultrasonic waves release their energy in multiple directions, thereby reducing interference from clutter on the monitoring wave and improving monitoring sensitivity and accuracy.

[0045] The ultrasonic transmission protrusion 213 is a wedge-shaped structure that is larger at the top and smaller at the bottom. When the ultrasonic wave generated by the ultrasonic transducer 22 is output from the ultrasonic transmission protrusion 213, the ultrasonic energy is concentrated at the lower end of the ultrasonic transmission protrusion 213, thereby improving the ultrasonic penetration ability and allowing the ultrasonic wave to better pass through the gas transmission pipeline.

[0046] A triangular structure is formed between the inclined surface a, the inclined surface b and the bottom plate 211, which reduces the direction of ultrasonic transmission, thereby reducing the generation of interference waves and improving the monitoring sensitivity of the ultrasonic gas flow meter.

[0047] Reference Figure 2 、 Figure 4 The clamping plate 23 is a Z-shaped structure. A limiting column 231 is fixed at the end where the clamping plate 23 is connected to the limiting bar 215. The limiting column 231 is clamped in the limiting hole 216. A connecting plate 232 is fixed at the end where the clamping plate 23 is connected to the locking platform 217. A plug-in protrusion 233 is fixed on the lower side of the connecting plate 232, and the plug-in protrusion 233 is inserted into the clamping groove 218; clamping limiting plates 234 are fixed on both sides of the clamping clamping plate 23; the clamping limiting plates 234 are clamped on both sides of the limiting protrusion 214.

[0048] When the pressing plate 23 is pressing the ultrasonic transducer 22, the limiting post 231 is connected to the limiting hole 216, the connecting plate 232 is connected to the locking platform 217, and the plug-in protrusion 233 is inserted into the clamping groove 218. The pressing limiting plate 234 is clamped on both sides of the limiting protrusion 214. Finally, two screws are passed through the connecting plate 232 to connect to the locking platform 217, and the pressing plate 23 is locked to the sonic wedge 21. At this time, the ultrasonic transducer 22 is locked on the sonic wedge 21.

[0049] The engagement of the insertion protrusion 233 with the engaging groove 218 and the engagement of the pressing limit plate 234 with the limiting protrusion 214 limits the horizontal displacement of the pressing plate 23. The engagement of the limiting post 231 with the limiting hole 216 and the connection of the two screws through the connecting plate 232 with the locking platform 217 limits the vertical displacement of the pressing plate 23, thereby stably fixing the ultrasonic transducer 22 on the acoustic wedge 21.

[0050] By plugging the limiting column 231 into the limiting hole 216 and the clamping plate 23 into a Z-shaped structure, and finally connecting it to the locking platform 217 through two screws through the connecting plate 232, the installation of the clamping plate 23 is more convenient and quick.

[0051] Reference Figure 2 、 Figure 3 、 Figure 5 、 Figure 6 The housing 25 includes an ultrasonic vibration chamber 251 and an ultrasonic divergence chamber 252. A clamping groove 253 is provided on the lower side of the housing 25. The bottom plate 211 is embedded in the clamping groove 253. A wire lead-out groove 254 is provided on the side of the ultrasonic vibration chamber 251 close to the ultrasonic divergence chamber 252. The bottom of the ultrasonic divergence chamber 252 is an arc-shaped structure. A pressing platform 255 is provided on the lower side of the housing 25. The clamping groove 253 is provided on the lower side of the pressing platform 255. Silicone is filled between the housing 25, the pressing plate 23 and the ultrasonic transducer 22.

[0052] After the ultrasonic transducer 22 is locked onto the sonic wedge 21 via the clamping plate 23, the ultrasonic transducer 22 and the clamping plate 23 are installed in the ultrasonic vibration cavity 251. The wire connected to the ultrasonic transducer 22 is placed in the wire lead-out groove 254. At this time, silicone is injected into the ultrasonic vibration cavity 251, and the bottom plate 211 of the sonic wedge 21 is embedded in the clamping groove 253, thereby installing the sonic wedge 21 in the housing 25. A spherical groove 219 is provided on the inclined surface b to align with the ultrasonic divergence cavity 252. The silicone filled in the housing 25 can absorb the ultrasonic waves generated by the inclined surfaces a and b of the sonic wedge 21, reducing the generation of clutter and thus reducing the impact of interference waves on the monitoring accuracy of the ultrasonic gas flowmeter.

[0053] The bottom of the ultrasonic divergence cavity 252 is an arc-shaped structure, and the spherical groove 219 is aligned with the ultrasonic divergence cavity 252. The ultrasonic waves emitted by the inclined surface b are then absorbed by the silica gel after being diverged, and then diverged again through the ultrasonic divergence cavity 252, thereby further weakening the ultrasonic waves emitted by the inclined surface b and reducing the generation of interference waves.

[0054] A clamping groove 253 is provided on the lower side of the shell 25; the bottom plate 211 is embedded in the clamping groove 253. When pressure is applied to the shell 25, the connection strength between the ultrasonic transmission protrusion 213 and the gas delivery pipe can be increased, so that the ultrasonic wave generated by the ultrasonic transmission protrusion 213 can better pass through the gas delivery pipe and be reflected inside the gas delivery pipe; when the reflected ultrasonic wave is better received by the ultrasonic transmission protrusion 213, a clearer interference wave can be obtained.

[0055] Reference Figure 1 、 Figure 7 、 Figure 8 A pair of clamps 51 are installed on the support frame 5, and a center groove 52 is opened on the support frame 5. The limit piece 3 is locked in the center groove 52, and a threaded hole 53 is opened on the support frame 5. The limit piece 3 is threadedly connected to the threaded hole 53 by a bolt 54 and locked on the support frame 5; a pair of ultrasonic generators 2 are installed on the lower side of the limit piece 3, and the limit piece 3 is threadedly connected to the threaded hole 53 by a bolt 54 and locked on the support frame 5. The limit piece 3 can be controlled to move up and down in the center groove 52 by the bolt 54 and the threaded hole 53, and the pressure between the ultrasonic transmission protrusion 213 and the gas delivery pipe can be controlled, and the tightness of the connection between the ultrasonic transmission protrusion 213 and the gas delivery pipe can be controlled, thereby reducing the energy loss of the ultrasonic wave when passing through the gas delivery pipe, so that the ultrasonic wave passing through the gas delivery pipe can be more stably transmitted and reflected inside the gas delivery pipe; at the same time, the reflected ultrasonic wave can be better received by the ultrasonic transmission protrusion 213, thereby obtaining a clearer interference wave.

[0056] Reference Figure 7 、 Figure 8 、 Figure 9、 Figure 10 、 Figure 11 、 Figure 13 The limiting member 3 includes a pressing member 31, a locking plate 32 is installed on the lower side of the pressing member 31, and a blocking plate 33 is installed on the upper side of the pressing member 31; a pair of mounting grooves 34 are opened on the pressing member 31, and a pressing groove 341 is opened on the lower side of the mounting groove 34. The pressing platform 255 is clamped in the pressing groove 341, and the locking plate 32 is locked to the bottom of the pressing member 31 by a plurality of screws; locking holes 35 are opened on both sides of the pressing member 31; bolts 54 pass through the locking holes 35 to lock the limiting member 3 on the support frame 5;

[0057] During the installation of the ultrasonic generator 2, the pressing platform 255 is clamped in the pressing groove 341, the ultrasonic transmission protrusion 213 passes through the positioning groove 321 provided on the locking plate 32, and then the locking plate 32 is fixed to the lower side of the lower pressing member 31 by multiple screws; thereby fixing the ultrasonic generator 2 to the lower pressing member 31. At this time, the bolt 54 passes through the locking hole 35 to lock the limiter 3 to the support frame 5. The limiter 3 is controlled to move downward by the bolt 54, so that the ultrasonic transmission protrusion 213 is tightly abutted against the gas transmission pipeline, thereby improving the coupling effect between the sonic wedge 21 and the gas transmission pipeline, reducing impedance, and making it easier for ultrasonic waves to pass through the gas transmission pipeline.

[0058] A plurality of isolation grooves 36 are formed on the lower pressing member 31. The isolation grooves 36 are arranged around the mounting groove 34. The ultrasonic waves are refracted during the lateral transmission process from the solid to the gas and then from the gas to the solid. Thus, the isolation grooves 36 can be used to reduce mutual interference between ultrasonic waves.

[0059] By reducing the generation of interference waves from the ultrasonic generator 2 and improving the structure of the sonic wedge 21, the tightness of the connection between the ultrasonic transmission protrusion 213 and the gas delivery pipeline is strengthened, the penetration of ultrasonic waves into the gas delivery pipeline is improved, and the contact between ultrasonic waves and gas in the gas delivery pipeline is increased through the principle of ultrasonic reflection, the sensitivity of the ultrasonic gas flowmeter in monitoring gas flow is improved, so that ultrasonic waves can obtain gas flow conditions at (100KPA under standard atmospheric pressure).

[0060] Reference Figure 12The ultrasonic transducer 22 includes a plurality of piezoelectric ceramic sheets 221. The piezoelectric ceramic sheets 221 form a matrix structure. The piezoelectric ceramic sheets 221 include piezoelectric ceramic layers 222. Electrode sheets 223 are provided on the upper and lower sides of the piezoelectric ceramic layers 222. The electrode sheets 223 are connected by conductive sheets 224. The thickness of the conductive sheets 224 is less than that of the electrode sheets 223. When a high-frequency current is input into the piezoelectric ceramic sheets, displacement occurs between the positive and negative conductive sheets of the piezoelectric ceramic sheets, thereby generating ultra-high frequency vibrations. The piezoelectric ceramic sheets 221 in the array structure can generate multiple ultrasonic beams (8 in the horizontal direction and 11 in the vertical direction, a total of 88 ultrasonic beams). By absorbing 88 ultrasonic waves into the gas delivery pipeline, the ultrasonic waves are reflected and then pass through the gas delivery pipeline to contact the sonic wedge 21, and then transmitted to the piezoelectric ceramic sheets, thereby generating wave interference. Under the action of the 88 ultrasonic waves, the constant cross-sectional area of ​​the ultrasonic waves passing through the gas is increased, thereby improving the sensitivity of the gas flow meter monitoring, so that even weak gas flows under normal pressure can be monitored.

[0061] The piezoelectric ceramic sheets 221 are bonded together by resin. The resin absorbs vibrations, thereby reducing the impact of vibrations between the piezoelectric ceramic sheets 221 and effectively improving the clarity of the generated ultrasonic waves.

[0062] The electrode sheets 223 are connected by the conductive sheet 224 so that current is transmitted to each electrode sheet 223 . The thickness of the conductive sheet 224 is smaller than that of the electrode sheet 223 , which can reduce the impact of vibration between the electrode sheets 223 and make the generated ultrasonic waves clearer.

[0063] The frequency of the piezoelectric ceramic piece 221 is 200KHZ-500KHZ. The higher the ultrasonic frequency, the stronger the penetrating ability and the shorter the propagation distance. The lower the ultrasonic frequency, the lower the penetrating ability and the longer the propagation distance. According to the characteristics of ultrasonic waves, the appropriate frequency of ultrasonic waves is selected according to the diameter of the gas transmission pipeline.

[0064] Reference Figure 14The data processor 4 includes a switching module 41, a sending circuit module 42, a receiving circuit module 43, a data processing module 44, a data storage module 45, a timing module 46, a pressure monitoring module 47, an input and output module 48 and a temperature monitoring module 49; the switching module 41 is electrically connected to the ultrasonic generator 2, the switching module 41 is electrically connected to the sending circuit module 42, the switching module 41 is electrically connected to the receiving circuit module 43, the sending circuit module 42 and the receiving circuit module 43 are electrically connected to the data processing module 44, the data storage module 45, the timing module 46, the pressure monitoring module 47 and the input and output module 48 are electrically connected to the data processing module 44; the input and output module 48 is connected to the display screen; the temperature monitoring module 49 is connected to the data processing module 44; (the gas flow calculation method is the existing technology, for the specific algorithm, please refer to paragraphs 49-59 of the specification in application number CN201480040147.1).

[0065] The switching module 41 is a component for switching between the transmission and reception of ultrasonic waves. The switching module 41 is connected to the two ultrasonic generators 2 and can include, for example, a selector switch. The switching module 41 switches the selector switch based on a control signal input from the data processing module 44. The transmission circuit module 42 is a component for transmitting ultrasonic waves to the ultrasonic generators 2. The transmission circuit module 42 can include, for example, an oscillator circuit that generates a rectangular wave of a predetermined frequency and a drive circuit for the ultrasonic generators 2. Based on the control signal input from the data processing module 44, the drive circuit in the transmission circuit module 42 outputs the rectangular wave generated by the oscillator circuit as a drive signal to the ultrasonic transducer 22 of the ultrasonic generator 2. This drives the ultrasonic transducer 22 in the ultrasonic generator 2, causing it to transmit ultrasonic waves.

[0066] The receiving circuit module 43 is a component for detecting ultrasonic waves received by the ultrasonic generator 2. For example, the receiving circuit module 43 may include an amplifier circuit for amplifying the signal at a predetermined gain, a filter circuit for extracting an electrical signal of a predetermined frequency, and the like. Based on a control signal input from the data processing module 44, the receiving circuit module 43 amplifies the electrical signal output from the ultrasonic generator 2, filters it, and converts it into a received signal. The receiving circuit module 43 outputs the converted received signal to the data processing module 44.

[0067] The timing module 46 is a component for measuring time within a predetermined period. The timing module 46 can be composed of, for example, an oscillator circuit. Furthermore, the oscillator circuit can be shared with the transmission circuit module 42. Based on the start and stop signals input from the data processing module 44, the timing module 46 counts the number of reference waves in the oscillator circuit and measures time. The timing module 46 outputs the measured time to the data processing module 44.

[0068] The data processing module 44 is a component for calculating the flow rate of gas flowing within the gas transmission pipeline through calculations. The data processing module 44 can be, for example, a CPU. The data processing module 44 controls the switching module 41, the transmission circuit module 42, the reception circuit module 43, the timing module 46, and the input / output module 48.

[0069] The input / output module 48 is a component used by the user to input information and output information to the user. The input / output module 48 can be composed of, for example, input means such as operation buttons and output means such as a display. By operating the operation buttons, the user inputs various information, such as settings, into the data processing module 44 via the input / output module 48. The data processing module 44 displays and outputs the gas flow rate, gas velocity, and accumulated flow rate information over a predetermined period calculated by the data processing module 44 on the display.

[0070] The pressure monitoring module 47 is usually connected to the pressure monitoring element, and transmits the electrical signal of the pressure monitoring element to the data processing module 44, which processes the electrical signal in digital form. The data storage module 45 stores the processed information, such as the gas pressure information in the pipeline, the real-time flow rate information of the gas in the pipeline, and the gas flow information in the pipeline; so as to facilitate the review of previous data; the temperature monitoring module 49 is used to monitor the gas temperature and ambient temperature.

[0071] The examples in this specific embodiment are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Identical components are denoted by the same reference numerals. Therefore, any equivalent changes made to the structure, shape, and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. An external clamp-on ultrasonic gas flowmeter, comprising an ultrasonic absorber (1) and a pair of ultrasonic generators (2) sleeved on a gas delivery pipe, characterized in that: A support frame (5) is installed on the ultrasonic absorber (1), a limiter (3) is installed on the support frame (5), the ultrasonic generator (2) is installed in the limiter (3), a data processor (4) is installed on the support frame (5), and the data processor (4) is electrically connected to the ultrasonic generator (2); the ultrasonic generator (2) is used to transmit and receive ultrasonic waves; the ultrasonic generator (2) includes a sonic wedge (21), an ultrasonic transducer (22) is clamped on the sonic wedge (21), a pressing plate (23) is installed on the sonic wedge (21), and the pressing plate (23) is electrically connected to the ultrasonic generator (21). 3) Used to lock the ultrasonic transducer (22) on the acoustic wedge (21), an isolation layer (24) is provided between the pressing plate (23) and the ultrasonic transducer (22); a housing (25) is provided on the outside of the pressing plate (23), and silica gel is filled between the housing (25), the pressing plate (23) and the ultrasonic transducer (22); the acoustic wedge (21) abuts against the gas delivery pipe; the ultrasonic wave generated by the ultrasonic generator (2) obliquely passes through the gas delivery pipe, and the ultrasonic wave contacts the inner wall of the gas delivery pipe, generates reflection, and then passes through the gas delivery pipe again and is received by another ultrasonic generator (2); The acoustic wedge (21) includes a base plate (211), a wedge-shaped body (212) is fixed on the upper side of the base plate (211), and an ultrasonic transmission protrusion (213) is fixed on the lower side of the base plate (211), the ultrasonic transmission protrusion (213) is pressed on the ultrasonic absorber (1), and the ultrasonic transmission protrusion (213) is a wedge-shaped structure with a larger upper part and a smaller lower part; the acoustic wedge (21) is an integral structure; the wedge-shaped body (212) includes an inclined surface a and an inclined surface b, and limiting protrusions (214) for limiting the pressing plate (23) and the ultrasonic transducer (22) are fixed on both sides of the inclined surface a, and the base plate (211) is close to the inclined surface. One end of surface a is provided with a limit strip (215) for limiting the pressing plate (23), and a limit hole (216) is provided on the limit strip (215); a locking platform (217) is fixed on the inclined surface b, and the pressing plate (23) is locked on the locking platform (217) by screws; a snap-fit ​​groove (218) is provided on the locking platform (217), and a spherical groove (219) is provided on the inclined surface b, and the spherical groove (219) is used to eliminate ultrasonic diffuse reflection; a triangular structure is formed between the inclined surface a, the inclined surface b and the bottom plate (211); and the angle between the inclined surface b and the bottom plate (211) is 49°-53°.

2. The clamp-on ultrasonic gas flowmeter according to claim 1, characterized in that: The ultrasonic generator (2) is located on the same side of the gas delivery pipeline, and the ultrasonic waves emitted by the ultrasonic generator (2) are reflected by the module in the delivery pipeline.

3. The clamp-on ultrasonic gas flowmeter according to claim 1, characterized in that: The material of the sonic wedge (21) is polyarylsulfone (PASF) material, and the sonic wedge (21) is cut by a numerically controlled machine tool.

4. The clamp-on ultrasonic gas flowmeter according to claim 1, characterized in that: The clamping plate (23) is a Z-shaped structure. A limiting column (231) is fixed at one end of the clamping plate (23) connected to the limiting bar (215), and the limiting column (231) is clamped in the limiting hole (216). A connecting plate (232) is fixed at one end of the clamping plate (23) connected to the locking platform (217), and a plug-in protrusion (233) is fixed on the lower side of the connecting plate (232), and the plug-in protrusion (233) is inserted into the clamping groove (218); clamping limiting plates (234) are fixed on both sides of the clamping plate (23), and the clamping limiting plates (234) are clamped on both sides of the limiting protrusion (214).

5. The clamp-on ultrasonic gas flowmeter according to claim 4, characterized in that: The housing (25) includes an ultrasonic vibration chamber (251) and an ultrasonic divergence chamber (252); a clamping groove (253) is provided on the lower side of the housing (25); the bottom plate (211) is embedded in the clamping groove (253); a wire lead-out groove (254) is provided on the side of the ultrasonic vibration chamber (251) close to the ultrasonic divergence chamber (252); the bottom of the ultrasonic divergence chamber (252) is an arc-shaped structure; a pressing platform (255) is provided on the lower side of the housing (25); the clamping groove (253) is provided on the lower side of the pressing platform (255).

6. The clamp-on ultrasonic gas flowmeter according to claim 5, characterized in that: A pair of hoops (51) are installed on the support frame (5), a central groove (52) is provided on the support frame (5), the limiting member (3) is locked in the central groove (52), a threaded hole (53) is provided on the support frame (5), and the limiting member (3) is threadedly connected to the threaded hole (53) by a bolt (54) and locked on the support frame (5).

7. The clamp-on ultrasonic gas flowmeter according to claim 6, characterized in that: The limiting member (3) includes a pressing member (31), a locking plate (32) is installed on the lower side of the pressing member (31), and a blocking plate (33) is installed on the upper side of the pressing member (31); a pair of mounting grooves (34) are provided on the pressing member (31), a pressing groove (341) is provided on the lower side of the mounting groove (34), the pressing platform (255) is clamped in the pressing groove (341), a positioning groove (321) is provided on the locking plate (32), and the ultrasonic transmission protrusion (213) The locking plate (32) is locked to the bottom of the pressing member (31) by a plurality of screws; locking holes (35) are provided on both sides of the pressing member (31); the bolts (54) pass through the locking holes (35) to lock the limiting member (3) to the support frame (5); a plurality of isolation grooves (36) are provided on the pressing member (31), the isolation grooves (36) are arranged around the mounting grooves (34), and the isolation grooves (36) are used to reduce mutual interference between ultrasonic waves.

8. The clamp-on ultrasonic gas flowmeter according to claim 1, characterized in that: The ultrasonic transducer (22) comprises a plurality of piezoelectric ceramic sheets (221); the piezoelectric ceramic sheets (221) form a matrix structure, the piezoelectric ceramic sheets (221) comprise a piezoelectric ceramic layer (222), and electrode sheets (223) are provided on the upper and lower sides of the piezoelectric ceramic layer (222); the electrode sheets (223) are connected to each other via a conductive sheet (224), and the thickness of the conductive sheet (224) is smaller than the thickness of the electrode sheet (223).

9. The clamp-on ultrasonic gas flowmeter according to claim 1, characterized in that: The data processor (4) includes a switching module (41), a sending circuit module (42), a receiving circuit module (43), a data processing module (44), a data storage module (45), a timing module (46), a pressure monitoring module (47), an input / output module (48) and a temperature monitoring module (49); the switching module (41) is electrically connected to the ultrasonic generator (2); the switching module (41) is electrically connected to the sending circuit module (42); the switching module (41) is electrically connected to the receiving circuit module (43); the sending circuit module (42) and the receiving circuit module (43) are electrically connected to the data processing module (44); the data storage module (45), the timing module (46), the pressure monitoring module (47) and the input / output module (48) are electrically connected to the data processing module (44); the input / output module (48) is connected to the display screen; and the temperature monitoring module (49) is connected to the data processing module (44).

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