Gas flow metering device based on gas ultrasonic metering

Abstract

This invention discloses a gas flow metering device based on ultrasonic gas metering, comprising a pressure reducing valve and an ultrasonic flow meter connected to the rear end of the pressure reducing valve via a delivery pipeline. The delivery pipeline has a first vertical pipe section, a connecting pipe section, and a second vertical pipe section connected in sequence, forming a V-shaped bend in the delivery pipeline. In the fluid flow direction within the delivery pipeline, the second vertical pipe section is located downstream of the first vertical pipe section, and the connection point of the second vertical pipe section on the connecting pipe section is located between the two ends of the connecting pipe section. A sludge collection device is also connected to the rear end of the connecting pipe section. The sludge collection device includes a sludge tank, with an inlet pipe at the upper end of the sludge tank connected to the rear end of the connecting pipe section, and a drain valve connected to the lower end of the sludge tank via an outlet pipe. The structural design provided by this solution can effectively improve the reliability of the ultrasonic flow meter's measurement results.

Description

Technical Field

[0001] This invention relates to the field of pipeline metering device technology, and in particular to a gas flow metering device based on ultrasonic gas metering. Background Technology

[0002] Flow meters are essential metering devices in natural gas pipeline systems. For a long time, the most common types of flow meters used in natural gas pipeline systems have been turbine flow meters and orifice plate flow meters. Mechanical metering devices have complex structures and are prone to blockage and corrosion of components due to water vapor, particulate matter, and other impurities carried in natural gas. This not only reduces the lifespan of the flow meter but also severely hinders accurate metering. Ultrasonic gas flow meters, on the other hand, utilize the relationship between the propagation speed of ultrasonic pulses in the airflow and the airflow velocity to determine the gas flow rate. Specifically, the ultrasonic pulse propagates faster with the flow direction than against the flow direction, and the greater the time difference between these two propagation speeds, the greater the flow rate. In recent years, with the development of ultrasonic metering technology, ultrasonic flow meters have not only significantly reduced costs but also, because their core structure consists of a circuit module and a transducer, ensure that their performance and lifespan are not excessively affected by the fluid medium. This results in ideal metering accuracy under various operating conditions, and they have now become internationally recognized natural gas metering devices.

[0003] When designing applications for ultrasonic flow meters, measurement accuracy is a key concern. Based on the characteristics of ultrasonic flow meters used in natural gas pipelines, their measurement accuracy is affected by the following factors: calibration status, flow velocity profile, temperature distribution, fluid pulsation, acoustic and electromagnetic noise, and contaminant deposition. To ensure flow measurement accuracy, relevant solutions are needed for each of these aspects.

[0004] Furthermore, the acoustic noise generally comes from rectifier components and throttling components, and the relevant pipe fittings are commonly rectifier mechanisms and pressure reducing valves on the pipeline; the contaminant is generally referred to as "black powder", which is a general term for abrasive substances that can be collected from natural gas pipelines and can exhibit a tar-like appearance.

[0005] Ultrasonic flow meters have become an important tool for natural gas metering, and improving the metering accuracy of ultrasonic flow meters will promote their further application. Summary of the Invention

[0006] To address the aforementioned goal of improving the metering accuracy of ultrasonic flow meters, this invention provides a gas flow metering device based on ultrasonic gas metering, taking into account the characteristics of ultrasonic flow meters used in natural gas pipelines. The structural design provided in this solution effectively improves the reliability of the ultrasonic flow meter's metering results.

[0007] To address the above problems, the gas flow metering device based on ultrasonic gas metering provided by the present invention solves the problems through the following technical points: The gas flow metering device based on ultrasonic gas metering includes a pressure reducing valve and an ultrasonic flow meter connected to the rear end of the pressure reducing valve through a delivery pipeline. The delivery pipeline has a first vertical pipe section, a connecting pipe section, and a second vertical pipe section connected in sequence. The first vertical pipe section, the connecting pipe section, and the second vertical pipe section form a Z-shaped bend on the delivery pipeline.

[0008] In the direction of fluid flow in the conveying pipeline, the second vertical pipe section is located downstream of the first vertical pipe section, the connection point of the second vertical pipe section on the connecting pipe section is located between the two ends of the connecting pipe section, and the rear end of the connecting pipe section is also connected to a sludge collection device.

[0009] The sludge collection device includes a sludge collection tank, the upper end of which is provided with an inlet pipe connected to the rear end of the connecting pipe section, and the lower end of which is connected to a drain valve through an outlet pipe.

[0010] The specific application of this scheme is as follows: it is connected in series with a natural gas pipeline to measure the flow rate of natural gas after pressure reduction. The fluid flow pattern of natural gas in this scheme is as follows: it enters the pressure reducing valve through the inlet of the pressure reducing valve, and after pressure reduction, it enters the delivery pipeline. The flow pattern in the delivery pipeline is that it passes through the first vertical pipe section, the connecting pipe section, and the second vertical pipe section in sequence, and then enters the ultrasonic flow meter.

[0011] The structural features of this scheme include:

[0012] 1. By placing the ultrasonic flow meter at the rear end of the pressure reducing valve, the pressure of the natural gas flowing through the ultrasonic flow meter is relatively stable, which is beneficial to the metering accuracy of the ultrasonic flow meter.

[0013] 2. By setting the delivery pipe to a Z-shaped bend, and the connection position of the second vertical pipe section on the connecting pipe section being located between the two ends of the connecting pipe section, the overall configuration of the delivery pipe is a "λ" configuration. When facing the ultrasonic waves generated by the pressure reducing valve, the delivery pipe can effectively isolate the ultrasonic waves from the pressure reducing valve, thereby achieving the purpose of ensuring the metering accuracy of the ultrasonic flow meter by improving the signal pickup quality of the sensor components on the ultrasonic flow meter.

[0014] 3. Based on the overall configuration of the pipeline as "λ", the system also includes the aforementioned sludge collection device. When liquid contaminants (including water) and solid contaminants (mainly black particles) flowing with natural gas pass through the connecting pipe section, these contaminants move further to the sludge collection tank under the action of inertia. This serves to: purify the natural gas flow; reduce the content of contaminants carried by the natural gas entering the ultrasonic flow meter; reduce the residue of contaminants on the sensor components and the inner wall of the flow channel, thereby ensuring the metering accuracy of the ultrasonic flow meter during its service life; and for the purpose of contaminant removal, compared to the separation of contaminants by the fluid passing through a filter device, this solution utilizes the pipeline configuration to allow these contaminants to actively separate from the gas flow under inertia. This reduces the pressure loss caused by contaminant separation, thus facilitating the transportation of natural gas through the pipeline.

[0015] Further explanation of the above scheme is as follows: After the pollutants carried by the natural gas gas flow in the connecting pipe section enter the sludge collection device through the inlet pipe, the sludge collection tank serves as a storage container for the pollutants. The drain valve is connected to the sludge collection tank through the outlet pipe and is used to continuously or intermittently discharge the pollutants in the sludge collection tank. In specific applications, considering safety, the drain valve is set to discharge intermittently. The intermittent discharge can be triggered by the control signal output by the timer or the control signal output by the pollutant detection device. However, when selecting the pollutant detection device, since the pollutants may have a large viscosity, it is not advisable to use a lever-type float valve as the pollutant detection device.

[0016] Furthermore, the connecting pipe section can be a straight pipe section or a curved pipe section, and the second vertical pipe section can also be connected at any circumferential position of the connecting pipe section. However, preferably, in order to improve the pollutant removal rate, the connecting pipe section is an arc-shaped pipe section of equal diameter, and the connection position of the second vertical pipe section in the circumferential direction of the connecting pipe section is located on the top side, front side or rear side (not the bottom side) of the connecting pipe section.

[0017] As a further technical solution for the gas flow metering device based on ultrasonic gas metering:

[0018] Both ends of the pressure reducing valve are provided with straight pipe sections coaxial with the pressure reducing valve, and both ends of the ultrasonic flow meter are provided with straight pipe sections coaxial with the ultrasonic flow meter.

[0019] The front end of the first vertical pipe section is connected to the straight pipe section at the rear end of the pressure reducing valve via an elbow, and the rear end of the first vertical pipe section is connected to the front end of the connecting pipe section via an elbow.

[0020] The second vertical pipe section connects to the connecting pipe section at its rear end, and the rear end of the second vertical pipe section connects to the straight pipe section at the front end of the ultrasonic flow meter via an elbow. In this scheme, the straight pipe sections at both ends of the ultrasonic flow meter and the pressure reducing valve are used to optimize the flow field and ensure the performance of the ultrasonic flow meter and the pressure reducing valve during use. This scheme proposes a specific form of pipeline connection, namely, connecting the corresponding pipe sections through elbows. In implementation, the elbows are preferably 90° long-diameter elbows.

[0021] The sludge collection device also includes an outer casing, with the sludge collection tank located within the outer casing. The outer casing is equipped with an insulation layer and / or an electric heating device. Specifically, this solution is applied as follows: throughout the entire working cycle, the substance inside the sludge collection tank is most likely a solid-liquid mixture. When this solution is applied to areas with low temperatures, the insulation layer utilizes the ground temperature to heat the fluid in the pipes and further transfer heat to the mixture, maintaining a relatively high temperature for the solid-liquid mixture while minimizing heat loss. The heat generated by the electric heating device further maintains a relatively high temperature for the solid-liquid mixture. Thus, given the increased fluidity of the solid-liquid mixture, the internal pressure of the sludge collection tank during use allows it to be smoothly discharged from the tank through a drain valve. Those skilled in the art should make a reasonable selection based on the climatic conditions of the area of ​​use and the installation method of the device (e.g., outdoor installation, concealed installation) when determining whether to choose an insulation or heating solution.

[0022] The above scheme proposes a technical solution to improve the reliability of ultrasonic flow meter measurement results from the perspective of pipeline configuration. The following scheme proposes a technical solution to improve the reliability of ultrasonic flow meter measurement results from the perspective of ultrasonic flow meter structural design.

[0023] Specifically:

[0024] The ultrasonic flow meter includes a flow channel and an ultrasonic transducer installed on the flow channel.

[0025] The ultrasonic transducer is adjustable in the radial direction of the flow channel. The ultrasonic transducer includes a sensor assembly. The adjustable position satisfies the following conditions: the center of the sensor assembly near the flow channel axis has a first state and a second state. The first state is that the center is located within the flow channel, and the second state is that the center is located on the inner wall boundary line of the flow channel. In the prior art, the center of the sensor assembly near the flow channel axis on an ultrasonic transducer is generally considered the probe center of the ultrasonic transducer. The installation position of the probe center relative to the flow channel sidewall is related to the channel length of the ultrasonic flow meter. When the probe center is located outside the inner wall boundary line of the flow channel (the state obtained by further moving the ultrasonic transducer outward in the first state), there is a non-fluid flow path in the channel. When calculating fluid flow rate by ultrasonic transmission time, this installation method has the problem of sound velocity changes affecting the measurement results. It also has the problem of easy contamination forming on the probe center, which also affects the ultrasonic transmission time. Therefore, the applicant believes that the first state, from the perspective of the influence of sound velocity changes on measurement, the contamination angle, and the front end of the sensor assembly (the end near the flow channel axis), is problematic. Both of these conditions are beneficial to the long-term accuracy of the ultrasonic flow meter, therefore the first state is the preferred installation method for the ultrasonic transducer. However, in practical applications, the first state also has the problem of contamination accumulation at the center of the probe. Therefore, this solution sets the position of the ultrasonic transducer in the radial direction of the flow channel to be adjustable and also has a second state. Specifically, during normal measurement, the ultrasonic transducer is in the first state, and after a certain period of use, it is adjusted to the second state. As those skilled in the art know, under the same flow rate, the fluid velocity at the center of the probe in the second state is greater than that in the first state, especially when the natural gas flow rate in the flow channel is low. In this way, the effect of the fluid in the second state on the contamination accumulated at the center of the probe can be used to remove the contamination, thereby ensuring the anti-contamination capability of the ultrasonic transducer. However, as those skilled in the art know, the ultrasonic flow meter should not be used in the second state for a long time during actual use: in the second state, the ultrasonic transducer extends more into the flow channel, which is detrimental to the stability and uniformity of the flow field in the flow channel, resulting in relatively poor measurement accuracy of the ultrasonic flow meter.

[0026] A connecting seat is provided on the flow channel;

[0027] The ultrasonic transducer includes a transducer housing, and the sensor assembly is mounted on the transducer housing;

[0028] The connecting seat is provided with an internal threaded hole, and the transducer housing is a columnar structure with external threads on the outside. The transducer housing is threadedly connected to the connecting seat: the transducer housing is threadedly connected to the internal threaded hole through its external threads.

[0029] The system also includes an end plug threaded into the internal threaded hole. The end plug is located outside the ultrasonic transducer within the internal threaded hole. The position of the ultrasonic transducer within the internal threaded hole is locked by the positive pressure exerted by the inner end face of the end plug on the outer end face of the transducer housing. This solution proposes a specific ultrasonic transducer installation method, specifically installing the ultrasonic transducer into the internal threaded hole of the connector via an external thread located on the outside of the transducer housing. Specifically, by rotating the transducer housing, the embedding depth of the ultrasonic transducer within the connector can be adjusted, thereby achieving the adjustable position. Furthermore, by including an end plug threaded into the internal threaded hole, after rotating the ultrasonic transducer to the desired connector depth, rotating the end plug utilizes the positive pressure provided by the inner end face of the end plug on the outer end face of the transducer housing to lock the ultrasonic transducer to a specific depth position within the connector. In practical applications, it is preferable that, since the sensor assembly is the front end of the ultrasonic transducer, its rear end needs to be equipped with lead wires. The transducer housing and the end plug can be respectively set as tubular and perforated plate shapes, with the channels on each serving as the wire holes for the lead wires. At the same time, the channels at the rear end of the transducer housing are set as internal hexagonal channels, and the channels on the end plug are also set as internal hexagonal channels. Furthermore, the internal hexagonal wrench used to operate the transducer housing can pass through the end plug and rotate without being affected by the end plug. In this way, the end plug and transducer housing can be rotated very conveniently.

[0030] The internally threaded hole has a stepped surface facing outwards. The transducer housing has a boss, and an elastic support is held between the inner end face of the boss and the stepped surface. During the process of the transducer housing penetrating the internally threaded hole and compressing the elastic support, the elastic support undergoes compressive elastic deformation. In both the first and second states, the elastic support is in a state of compressive elastic deformation. The design purpose of this solution is to increase the resistance to the rotation of the transducer housing by utilizing the force exerted by the elastic support on the transducer housing during the relevant state adjustment process, and to reduce the possibility of the transducer housing rotating with the end plug during the rotation of the end plug, thereby improving the accuracy of channel length control. As those skilled in the art, in the first and second states, the elastic support has different elastic compression amounts along the axis of the connecting seat. In practical applications, anti-rotation shims, thrust bearings, or lubricating coatings can be installed between the end plug and the transducer housing to prevent the end plug from driving the transducer housing to rotate. To ensure the angle / coaxiality of the ultrasonic transducer with the designed sound channel, the elastic support can be a discontinuous structure providing multi-point support, i.e., multiple elastic supports are evenly arranged around the circumference of the ultrasonic transducer. However, a preferred application is to use an annular sealing ring as the elastic support, which also provides axial sealing between the ultrasonic transducer and the connecting seat, or assists in ensuring reliable axial connection. For sealing: A preferred application is to install additional annular sealing rings between the outer side of the transducer housing and the inner sidewall of the connecting seat. These additional annular sealing rings provide radial constraint to the outer side of the transducer housing to maintain the angle / coaxiality. They also provide axial sealing to the gap between the ultrasonic transducer and the connecting seat during state adjustment, ensuring that state adjustments do not affect the ventilation status of the device. This allows for real-time state adjustment during gas delivery. The following scheme, which uses a clamping flange to provide end constraint for the transducer housing, can also utilize this scheme with annular sealing rings and other annular sealing rings. For those skilled in the art, the terms "annular sealing ring" and "other annular sealing rings" are merely a naming convention to distinguish annular sealing rings installed in different locations.

[0031] In specific pipeline applications, although the delivery pipeline can be used to isolate the ultrasonic waves from the pressure reducing valve, complete isolation cannot be guaranteed from the perspective of ultrasonic signal interference. The above provides an ultrasonic transducer installation scheme that can achieve relevant state adjustment. This scheme has the characteristics of simple structure and state adjustment scheme, but the corresponding threaded connection also results in a large noise propagation cross-section between the pipeline and the sensor assembly. Therefore, from the perspective of noise protection, this scheme is not the optimal solution. Based on this, the following parallel technical solutions for ultrasonic transducer installation are provided.

[0032] A connecting seat is provided on the flow channel;

[0033] The ultrasonic transducer includes a transducer housing, and the sensor assembly is mounted on the transducer housing;

[0034] The connecting seat is provided with a central hole, the central hole has a stepped surface facing outward from the central hole, the transducer housing has a boss, the transducer housing is embedded in the central hole, and an elastic support is held between the inner end face of the boss and the stepped surface.

[0035] It also includes a clamping flange and a first gasket, as well as clamping screws for connecting the clamping flange to the connecting seat screws;

[0036] The clamping flange fixes the ultrasonic transducer in the radial direction of the flow channel by exerting force on the outer end face of the transducer housing through its inner end face. The first pad is used as follows: when the first pad is clamped between the end face of the clamping flange and the connecting seat, the second state is obtained; after removing the first pad between the clamping flange and the connecting seat and tightening the clamping screw, the first state is obtained.

[0037] During the process of the transducer housing penetrating the central hole and compressing the elastic support, the elastic support undergoes compressive elastic deformation; in the first and second states, the elastic support is in a state of compressive elastic deformation. Unlike the above solutions, this solution utilizes a clamping flange. With the assistance of clamping screws, the inner end face of the clamping flange provides force to the outer end face of the transducer housing to constrain the position of the ultrasonic transducer in the central hole of the connecting seat. Under this design, there is no threaded pair between the transducer housing and the connecting seat, and it provides a structural basis for setting a second gasket between the clamping flange and the transducer housing. This makes this solution a technically advantageous solution for improving the metering accuracy of ultrasonic flowmeters from the perspective of noise blocking. Specifically: Regarding the relevant state adjustments, when the first pad is installed between the clamping flange and the end face of the connecting seat, the support provided by the first pad to the clamping flange allows the sensor assembly to be in the first state. When the first pad is removed, the clamping flange moves a certain distance towards the flow channel axis. At this time, the inner end face of the clamping flange moves further towards the connecting seat on the axis of the central hole, which can achieve the purpose of pushing the transducer housing further towards the flow channel to obtain the second state. Furthermore, the elastic support between the boss and the stepped surface not only provides support for the transducer housing towards the side where the clamping flange is located, but also continuously provides a thrust away from the flow channel to the clamping screw through compression elastic deformation, thus achieving the purpose of preventing loosening of the clamping flange. This purpose is beneficial to the accuracy of the channel length. As those skilled in the art, the first pad is used to control the relative position of the clamping flange and the connecting seat after the connection is completed. In specific applications, whether in the first state or the second state, the tightness of the clamping screw must be sufficient to lock the clamping flange onto the connecting seat. In both of the above schemes, the elastic support components must meet the compressive elastic deformation required for state adjustment.

[0038] The transducer housing is spaced apart from the wall of the central hole;

[0039] A second gasket, made of polymer material, is also provided between the clamping flange and the transducer housing. In this design, the phase gap is a non-contact fit to achieve noise blocking. Other annular sealing rings mentioned above can be used as a means to achieve this. To optimize the noise blocking effect, both the annular sealing ring and other annular sealing rings are O-rings. The second gasket is a specific application of the aforementioned structural basis, used to optimize the impact of noise on measurement accuracy.

[0040] The second gasket is made of Teflon. In this solution, Teflon is a high-performance sound-blocking material, and its material properties are used to block the propagation of surface noise. The non-stick properties, thermal stability, wear resistance, corrosion resistance, and sliding properties of Teflon are used to ensure the positional accuracy of the ultrasonic transducer and reduce the degree or possibility of deviation of the ultrasonic transducer axis due to friction during the assembly of the clamping flange.

[0041] The phase spacing is achieved by an axial sealing ring disposed between the wall of the central hole and the outer wall of the transducer housing. Those skilled in the art will recognize that the axial sealing ring in this solution is the other annular sealing ring described above.

[0042] The present invention has the following beneficial effects:

[0043] 1. By placing the ultrasonic flow meter at the rear end of the pressure reducing valve, the pressure of the natural gas flowing through the ultrasonic flow meter is relatively stable, which is beneficial to the metering accuracy of the ultrasonic flow meter.

[0044] 2. By setting the delivery pipe to a Z-shaped bend, and the connection position of the second vertical pipe section on the connecting pipe section being located between the two ends of the connecting pipe section, the overall configuration of the delivery pipe is a "λ" configuration. When facing the ultrasonic waves generated by the pressure reducing valve, the delivery pipe can effectively isolate the ultrasonic waves from the pressure reducing valve, thereby achieving the purpose of ensuring the metering accuracy of the ultrasonic flow meter by improving the signal pickup quality of the sensor components on the ultrasonic flow meter.

[0045] 3. Based on the overall "λ" configuration of the pipeline, a sludge collection device is also included. When liquid contaminants (including water) and solid contaminants (mainly black particles) flowing with natural gas pass through the connecting pipe section, these contaminants move further to the sludge collection tank under the action of inertia. This serves to: purify the natural gas flow; reduce the content of contaminants carried by the natural gas entering the ultrasonic flow meter; reduce the residue of contaminants on the sensor components and the inner wall of the flow channel, thereby ensuring the metering accuracy of the ultrasonic flow meter during its service life; regarding the purpose of contaminant removal, compared to the separation of contaminants by the fluid passing through a filter device, this solution utilizes the pipeline configuration to allow these contaminants to actively separate from the gas flow under inertia. This reduces the pressure loss caused by contaminant separation, thus facilitating the transportation of natural gas through the pipeline. (See attached diagram for details.)

[0046] Figure 1 This is a front view of a specific embodiment of the gas flow metering device based on ultrasonic gas metering described in this solution;

[0047] Figure 2This is a cross-sectional view of a specific embodiment of the gas flow metering device based on ultrasonic gas metering described in this solution, and a cross-sectional view of the dirt accumulation device. This cross-sectional view only shows the outer casing.

[0048] Figure 3 This is a partial structural cross-sectional view of a specific embodiment of the ultrasonic flow meter described in this solution, which can mitigate the impact of pollutants on measurement accuracy; a cross-sectional view of the connection seat location.

[0049] Figure 4 In order to be in Figure 3 Based on this, the installation state of the ultrasonic transducer was adjusted from the first state to the second state;

[0050] Figure 5 This is a partial structural cross-sectional view of a specific embodiment of the ultrasonic flowmeter described in this solution, which can mitigate the impact of pollutants on measurement accuracy. The corresponding structure in this cross-sectional view adopts a different approach than... Figure 3 and Figure 4 The structure used.

[0051] The reference numerals in the attached drawings are as follows: 1. Conveying pipe; 2. Pressure reducing valve; 3. First vertical pipe section; 4. Second vertical pipe section; 5. Connecting pipe section; 6. Drain valve; 7. Sludge collection device; 71. Outer casing; 72. Sludge collection tank; 73. Inlet pipe; 74. Electric heating device; 75. Outlet pipe; 8. Ultrasonic flow meter; 81. Flow channel; 82. Connecting seat; 83. First gasket; 84. Compression flange; 85. Transducer housing; 86. Sensor assembly; 87. Inner wall boundary line; 88. End plug; 89. Second gasket. Detailed Implementation

[0052] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments:

[0053] Example 1:

[0054] like Figures 1 to 5 As shown, the gas flow metering device based on ultrasonic gas metering includes a pressure reducing valve 2 and an ultrasonic flow meter 8 connected to the rear end of the pressure reducing valve 2 via a delivery pipe 1. The delivery pipe 1 has a first vertical pipe section 3, a connecting pipe section 5, and a second vertical pipe section 4 connected in sequence. The first vertical pipe section 3, the connecting pipe section 5, and the second vertical pipe section 4 form a Z-shaped bend on the delivery pipe 1.

[0055] In the direction of fluid flow in the conveying pipe 1, the second vertical pipe section 4 is located downstream of the first vertical pipe section 3, the connection point of the second vertical pipe section 4 on the connecting pipe section 5 is located between the two ends of the connecting pipe section 5, and the rear end of the connecting pipe section 5 is also connected to a sludge collection device 7.

[0056] The sludge accumulation device 7 includes a sludge accumulation tank 72. The upper end of the sludge accumulation tank 72 is provided with an inlet pipe 73 connected to the rear end of the connecting pipe section 5. The lower end of the sludge accumulation tank 72 is connected to a drain valve 6 through an outlet pipe 75.

[0057] The specific application of this scheme is as follows: it is connected in series with a natural gas pipeline to measure the flow rate of natural gas after pressure reduction. The fluid flow pattern of natural gas in this scheme is as follows: it enters the pressure reducing valve 2 through the inlet of the pressure reducing valve 2, and after pressure reduction, it enters the delivery pipeline 1. The flow pattern in the delivery pipeline 1 is that it passes through the first vertical pipe section 3, the connecting pipe section 5, and the second vertical pipe section 4 in sequence, and then enters the ultrasonic flow meter 8.

[0058] The structural features of this scheme include:

[0059] 1. By placing the ultrasonic flow meter 8 at the rear end of the pressure reducing valve 2, the pressure of the natural gas flowing through the ultrasonic flow meter 8 is relatively stable, which is beneficial to the metering accuracy of the ultrasonic flow meter 8.

[0060] 2. By setting the conveying pipe 1 into a Z-shaped bend, and the connection position of the second vertical pipe section 4 on the connecting pipe section 5 being located between the two ends of the connecting pipe section 5, the overall configuration of the conveying pipe 1 is a "λ" configuration. When facing the ultrasonic waves generated by the working pressure reducing valve 2, the conveying pipe 1 can effectively isolate the ultrasonic waves from the pressure reducing valve 2, thereby achieving the purpose of ensuring the metering accuracy of the ultrasonic flow meter 8 by improving the signal pickup quality of the sensor component 86 on the ultrasonic flow meter 8.

[0061] 3. Based on the overall configuration of the conveying pipeline 1 as a "λ" configuration, the system also includes the aforementioned sludge collection device 7. When liquid contaminants (including water) and solid contaminants (mainly black particles) flowing with natural gas pass through the connecting pipe section 5, these contaminants move further to the sludge collection tank 72 under the action of inertia. This serves to: purify the natural gas flow; reduce the content of contaminants carried by the natural gas entering the ultrasonic flow meter 8; reduce the residue of contaminants on the sensor assembly 86 and the inner wall of the flow channel 81; and ensure the metering accuracy of the ultrasonic flow meter 8 during its service life. Regarding the purpose of contaminant removal, compared to the method of separating contaminants by the fluid passing through a filter device, this solution utilizes the pipeline configuration to allow these contaminants to actively separate from the gas flow under inertia. This reduces the pressure loss caused by contaminant separation, thereby facilitating the transportation of natural gas through the pipeline.

[0062] Further explanation of the above scheme is as follows: After the pollutants carried by the natural gas gas flow in the connecting pipe section 5 enter the sludge collection device 7 through the inlet pipe 73, the sludge collection tank 72 serves as a storage container for the pollutants. The drain valve 6 is connected to the sludge collection tank 72 through the outlet pipe 75 and is used to continuously or intermittently discharge the pollutants in the sludge collection tank 72. In specific applications, considering safety, the drain valve 6 is set to discharge pollutants intermittently. The intermittent discharge can be triggered by the control signal output by the timer or the control signal output by the pollutant detection device. However, when selecting the pollutant detection device, since the pollutants may have a large viscosity, it is not advisable to use a lever-type float valve as the pollutant detection device.

[0063] Furthermore, the connecting pipe section 5 can be a straight pipe section or a curved pipe section, and the second vertical pipe section 4 can also be connected at any circumferential position of the connecting pipe section 5. However, preferably, in order to improve the pollutant removal rate, the connecting pipe section 5 is an arc-shaped pipe section of equal diameter, and the connection position of the second vertical pipe section 4 in the circumferential direction of the connecting pipe section 5 is located on the top side, front side or rear side (not the bottom side) of the connecting pipe section 5.

[0064] Example 2:

[0065] This embodiment is a further refinement of embodiment 1:

[0066] Both ends of the pressure reducing valve 2 are provided with straight pipe sections coaxial with the pressure reducing valve 2, and both ends of the ultrasonic flow meter 8 are provided with straight pipe sections coaxial with the ultrasonic flow meter 8.

[0067] The front end of the first vertical pipe section 3 is connected to the straight pipe section at the rear end of the pressure reducing valve 2 via an elbow, and the rear end of the first vertical pipe section 3 is connected to the front end of the connecting pipe section 5 via an elbow.

[0068] The second vertical pipe section 4 is connected to the connecting pipe section 5 at its rear end. The rear end of the second vertical pipe section 4 is connected to the straight pipe section at the front end of the ultrasonic flow meter 8 via an elbow. In this scheme, the straight pipe sections at both ends of the ultrasonic flow meter 8 and the pressure reducing valve 2 are used to optimize the flow field and ensure the performance of the ultrasonic flow meter 8 and the pressure reducing valve 2 during use. This scheme proposes a specific form of connection for the conveying pipe 1 on the pipeline, namely, the connection of the corresponding pipe sections is achieved through elbows. In implementation, the elbows are preferably 90° long-diameter elbows.

[0069] Example 3:

[0070] This embodiment is a further refinement of embodiment 1:

[0071] The sludge collection device also includes an outer casing 71, with the sludge collection tank 72 located inside the outer casing 71. The outer casing 71 is equipped with an insulation layer and / or an electric heating device 74. Specifically, during the entire working cycle, the substance inside the sludge collection tank 72 is more likely to be a solid-liquid mixture. When this solution is applied to areas with low temperatures, the insulation layer utilizes the ground temperature to heat the fluid in the pipes and further transfer heat to the mixture, maintaining a relatively high temperature for the solid-liquid mixture while minimizing heat loss. The heat generated by the electric heating device 74 further maintains a relatively high temperature for the solid-liquid mixture. Thus, with higher fluidity, the internal pressure of the sludge collection tank 72 during use allows the mixture to be smoothly discharged from the tank 72 through the drain valve 6. Those skilled in the art should make a reasonable selection based on the climate conditions of the area of ​​use and the installation method of the device (e.g., outdoor installation, concealed installation) when determining whether to choose an insulation or heating solution.

[0072] In the above embodiments, a technical solution for improving the reliability of the measurement results of the ultrasonic flow meter 8 from the perspective of pipeline configuration is proposed. In the following embodiments, a technical solution for improving the reliability of the measurement results of the ultrasonic flow meter 8 from the perspective of the structural design of the ultrasonic flow meter 8 is proposed.

[0073] Example 4:

[0074] This embodiment is a further refinement of embodiment 1:

[0075] The ultrasonic flow meter 8 includes a flow channel 81 and an ultrasonic transducer installed on the flow channel 81.

[0076] The position of the ultrasonic transducer in the radial direction of the flow channel 81 is adjustable. The ultrasonic transducer includes a sensor assembly 86. The position is adjustable to satisfy the following: the center of the end of the sensor assembly 86 near the axis of the flow channel 81 has a first state and a second state. The first state is that the center is located in the flow channel 81, and the second state is that the center is located on the inner wall boundary line 87 of the flow channel 81. In the prior art, the center of the sensor assembly 86 on the ultrasonic transducer, near the axis of the flow channel 81, is generally considered to be the probe center of the ultrasonic transducer. The installation position of the probe center relative to the sidewall of the flow channel 81 is related to the channel length of the ultrasonic flow meter 8. When the probe center is located outside the inner wall boundary line 87 of the flow channel 81 (the state obtained when the ultrasonic transducer moves further outward towards the flow channel 81 in the first state), there is a non-fluid flow path in the channel. When calculating the fluid flow rate by the ultrasonic transmission time, this installation method has the problem that changes in sound velocity affect the measurement result. At the same time, there is a problem that dirt can easily accumulate on the probe center, which can also affect the ultrasonic transmission time. Therefore, the applicant believes that: from the perspective of the influence of sound velocity change on measurement, the dirt accumulation angle, and the front end of the sensor assembly 86 (near the axis of the flow channel 81) in the first state... Both the first and second states are beneficial to the long-term accuracy of the ultrasonic flow meter 8, making the first state a preferred installation method for the ultrasonic transducer. However, in practical applications, the first state also suffers from the problem of contamination at the probe center. Therefore, this solution sets the position of the ultrasonic transducer in the radial direction of the flow channel 81 to be adjustable and also includes the second state. Specifically, the ultrasonic transducer is in the first state during normal metering, and is adjusted to the second state after a certain period of use. As those skilled in the art know, under the same flow rate, the fluid velocity at the probe center in the second state is greater than that in the first state, especially under low natural gas flow rates in the flow channel 81. Thus, the fluid in the second state can remove the contamination at the probe center, thereby ensuring the ultrasonic transducer's anti-contamination capability. However, as those skilled in the art know, the ultrasonic flow meter 8 should not be used in the second state for extended periods during actual use: in the second state, the ultrasonic transducer extends more into the flow channel 81, which is detrimental to the stability and uniformity of the flow field within the flow channel 81, resulting in relatively poor metering accuracy of the ultrasonic flow meter 8.

[0077] Example 5:

[0078] This embodiment is a further refinement of embodiment 4:

[0079] A connecting seat 82 is provided on the flow channel 81;

[0080] The ultrasonic transducer includes a transducer housing 85, and the sensor assembly 86 is mounted on the transducer housing 85;

[0081] The connecting seat 82 is provided with an internal threaded hole, and the transducer housing 85 is a columnar structure with external threads on the outside. The transducer housing 85 is threadedly connected to the connecting seat 82: the transducer housing 85 is threadedly connected to the internal threaded hole through its external threads.

[0082] The system also includes an end plug 88 threaded into the internal threaded hole. The end plug 88 is located outside the ultrasonic transducer in the internal threaded hole. The position of the ultrasonic transducer in the internal threaded hole is locked by the positive pressure exerted by the inner end face of the end plug 88 on the outer end face of the transducer housing 85. This solution proposes a specific ultrasonic transducer installation method, specifically, the ultrasonic transducer is installed in the internal threaded hole of the connecting seat 82 through an external thread located on the outside of the transducer housing 85. Specifically, by rotating the transducer housing 85, the embedding depth of the ultrasonic transducer in the connecting seat 82 can be adjusted, thereby achieving the adjustable position. Furthermore, by including the end plug 88 threaded into the internal threaded hole, after rotating the ultrasonic transducer to the desired depth in the connecting seat 82, rotating the end plug 88 utilizes the positive pressure provided by the inner end face of the end plug 88 on the outer end face of the transducer housing 85 to lock the ultrasonic transducer to a specific depth position in the connecting seat 82. In practical applications, it is preferable that, since the sensor assembly 86 serves as the front end of the ultrasonic transducer, its rear end needs to be equipped with lead wires. The transducer housing 85 and the end plug 88 can be respectively configured as tubular and perforated plate, with the channels on each serving as the wire holes for the lead wires. At the same time, the channels at the rear end of the transducer housing 85 and the channels on the end plug 88 are configured as internal hexagonal channels. Furthermore, the internal hexagonal wrench used to operate the transducer housing 85 can pass through the end plug 88 and rotate without being affected by the end plug 88. In this way, the end plug 88 and the transducer housing 85 can be rotated very conveniently.

[0083] Example 6:

[0084] This embodiment is a further refinement of embodiment 5:

[0085] The internally threaded hole has a stepped surface facing outwards from the internally threaded hole. The transducer housing 85 has a boss, and an elastic support is held between the inner end face of the boss and the stepped surface. During the process of the transducer housing 85 penetrating the internally threaded hole and pressing the elastic support, the elastic support undergoes compressive elastic deformation. In the first and second states, the elastic support is in a state of compressive elastic deformation. The design purpose of this solution is to increase the resistance to the rotation of the transducer housing 85 by utilizing the force exerted by the elastic support on the transducer housing 85 during the relevant state adjustment process, and to reduce the possibility that the transducer housing 85 rotates with the end plug 88 during the rotation of the end plug 88 and its action on the transducer housing 85, thereby improving the accuracy of the channel length control. As those skilled in the art, in the first and second states, the elastic support has different elastic compression amounts on the axis of the connecting seat 82. In practical applications, anti-rotation shims, thrust bearings, or lubricating coatings can be provided between the end plug 88 and the transducer housing 85 to prevent the end plug 88 from driving the transducer housing 85 to rotate. In practical applications, to ensure the angle / coaxiality of the ultrasonic transducer with the designed sound channel, the elastic support can be a discontinuous structure providing multi-point support, i.e., multiple elastic supports are evenly arranged around the circumference of the ultrasonic transducer. However, a preferred application is to use an annular sealing ring as the elastic support, so that it also provides axial sealing of the gap between the ultrasonic transducer and the connecting seat 82 or assists in achieving reliable axial sealing. Sealing: A preferred application is to provide additional annular sealing rings between the outer side of the transducer housing 85 and the inner sidewall of the connecting seat 82. These additional annular sealing rings provide radial constraint to the outer side of the transducer housing 85 to maintain the angle / coaxiality. They also provide axial sealing to the gap between the ultrasonic transducer and the connecting seat 82 during state adjustment, ensuring that state adjustments do not affect the ventilation status of the device, allowing for real-time state adjustment during gas delivery. The scheme using a clamping flange 84 to provide end constraint for the transducer housing 85 can also utilize this scheme with annular sealing rings and other annular sealing rings. For those skilled in the art, the terms "annular sealing ring" and "other annular sealing rings" are merely a naming convention to distinguish annular sealing rings installed in different positions.

[0086] Example 7:

[0087] This embodiment is a further refinement of embodiment 4:

[0088] As those skilled in the art, in specific pipeline applications, although the delivery pipeline 1 can be used to isolate the ultrasonic waves from the pressure reducing valve 2, from the perspective of ultrasonic signal interference, complete isolation cannot be guaranteed. The above provides an ultrasonic transducer installation scheme that can achieve relevant state adjustment. This scheme has the characteristics of simple structure and state adjustment scheme, but the corresponding threaded connection also results in a large noise propagation cross-sectional area between the pipeline and the sensor assembly 86. Therefore, from the perspective of noise protection, this scheme is not the optimal one. Based on this, the following parallel technical solutions for ultrasonic transducer installation are provided.

[0089] In this embodiment, a connecting seat 82 is provided on the flow channel 81;

[0090] The ultrasonic transducer includes a transducer housing 85, and the sensor assembly 86 is mounted on the transducer housing 85;

[0091] The connecting seat 82 is provided with a central hole, the central hole has a stepped surface facing outward from the central hole, the transducer housing 85 has a boss, the transducer housing 85 is embedded in the central hole, and an elastic support member is held between the inner end face of the boss and the stepped surface.

[0092] It also includes a clamping flange 84 and a first gasket 83, and a clamping screw for screwing the clamping flange 84 and the connecting seat 82.

[0093] The clamping flange 84 fixes the ultrasonic transducer in the radial direction of the flow channel 81 by exerting force on the outer end face of the transducer housing 85 through its inner end face. The first pad 83 is used as follows: when the first pad 83 is clamped between the end faces of the clamping flange 84 and the connecting seat 82, the second state is obtained; after removing the first pad 83 between the clamping flange 84 and the connecting seat 82 and tightening the clamping screw, the first state is obtained.

[0094] During the process of the transducer housing 85 penetrating the central hole and pressing the elastic support, the elastic support undergoes compressive elastic deformation; in the first and second states, the elastic support is in a state of compressive elastic deformation. Unlike the above solutions, this solution utilizes a clamping flange 84. With the assistance of clamping screws, the inner end face of the clamping flange 84 provides force to the outer end face of the transducer housing 85 to constrain the position of the ultrasonic transducer in the central hole of the connecting seat 82. Under this design, there is no threaded pair between the transducer housing 85 and the connecting seat 82, and it provides a structural basis for setting a second pad 89 between the clamping flange 84 and the transducer housing 85. This makes this solution a technically advantageous solution for improving the metering accuracy of the ultrasonic flow meter 8 from the perspective of noise blocking. Specifically: Regarding the relevant state adjustments, when the first pad 83 is installed between the end face of the clamping flange 84 and the connecting seat 82, the support provided by the first pad 83 to the clamping flange 84 keeps the sensor assembly in the first state. When the first pad 83 is removed, the clamping flange 84 moves a certain distance towards the axis of the flow channel 81. At this time, the inner end face of the clamping flange 84 moves further towards the connecting seat 82 on the axis of the central hole, which can push the transducer housing 85 further towards the flow channel 81 to achieve the purpose of obtaining the second state. Furthermore, the elastic support between the boss and the stepped surface not only provides support for the transducer housing 85 towards the side where the clamping flange 84 is located, but also continuously provides a thrust away from the flow channel 81 to the clamping screw through compression elastic deformation, thus achieving the purpose of preventing the clamping flange 84 from loosening. This purpose is beneficial to the accuracy of the channel length. As those skilled in the art know, the first pad 83 is used to control the relative position of the clamping flange 84 and the connecting seat 82 after the connection is completed. In specific applications, whether in the first state or the second state, the tightness of the clamping screws must be sufficient to lock the clamping flange 84 onto the connecting seat 82. At the same time, in both of the above schemes, the elastic support must meet the compressive elastic deformation required for state adjustment.

[0095] Example 8:

[0096] This embodiment is a further refinement of embodiment 7:

[0097] The transducer housing 85 is spaced apart from the wall of the central hole;

[0098] A second gasket 89, made of polymer material, is also provided between the clamping flange 84 and the transducer housing 85. In this design, the phase gap is a non-contact fit to achieve noise blocking. Other annular sealing rings mentioned above can be used as a means to optimize the noise blocking effect. O-rings are used for both the annular sealing ring and other annular sealing rings. The second gasket 89 is a specific application of the aforementioned structural basis, used to optimize the impact of noise on measurement accuracy.

[0099] Example 9:

[0100] This embodiment is a further refinement of embodiment 8:

[0101] The second pad 89 is made of Teflon. In this solution, Teflon is a high-performance sound-blocking material, and its material properties are used to block the propagation of surface noise. The non-stick properties, thermal stability, wear resistance, corrosion resistance, and sliding properties of Teflon are used to ensure the positional accuracy of the ultrasonic transducer and reduce the degree or possibility of deviation of the ultrasonic transducer axis due to friction during the assembly of the clamping flange 84.

[0102] Example 10:

[0103] This embodiment is a further refinement of embodiment 8:

[0104] The phase spacing is achieved by an axial sealing ring disposed between the wall of the central hole and the outer wall of the transducer housing 85. Those skilled in the art will recognize that the axial sealing ring in this solution is the other annular sealing ring described above.

[0105] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, other embodiments derived without departing from the technical solution of the present invention should be included within the scope of protection of the present invention.

Claims

1. A gas flow metering device based on ultrasonic gas metering, comprising a pressure reducing valve (2) and an ultrasonic flow meter (8) connected to the rear end of the pressure reducing valve (2) via a delivery pipe (1), characterized in that, The conveying pipeline (1) has a first vertical pipe section (3), a connecting pipe section (5) and a second vertical pipe section (4) connected in sequence, and the first vertical pipe section (3), the connecting pipe section (5) and the second vertical pipe section (4) form a Z-shaped bend on the conveying pipeline (1); In the direction of fluid flow in the conveying pipe (1), the second vertical pipe section (4) is located downstream of the first vertical pipe section (3), the connection point of the second vertical pipe section (4) on the connecting pipe section (5) is located between the two ends of the connecting pipe section (5), and the rear end of the connecting pipe section (5) is also connected to a sludge collection device (7). The sludge collection device (7) includes a sludge collection tank (72), the upper end of which is provided with an inlet pipe (73) connected to the rear end of the connecting pipe section (5), and the lower end of the sludge collection tank (72) is connected to a drain valve (6) through an outlet pipe (75). Both ends of the pressure reducing valve (2) are provided with straight pipe sections coaxial with the pressure reducing valve (2), and both ends of the ultrasonic flow meter (8) are provided with straight pipe sections coaxial with the ultrasonic flow meter (8). The front end of the first vertical pipe section (3) is connected to the straight pipe section at the rear end of the pressure reducing valve (2) through an elbow, and the rear end of the first vertical pipe section (3) is connected to the front end of the connecting pipe section (5) through an elbow. The connection position of the second vertical pipe section (4) on the connecting pipe section (5) is located at the rear end of the connecting pipe section (5), and the rear end of the second vertical pipe section (4) is connected to the straight pipe section at the front end of the ultrasonic flow meter (8) through an elbow; The sludge collection device (7) also includes an outer shell (71), the sludge collection tank (72) is located inside the outer shell (71), and the outer shell (71) is provided with a heat insulation layer and / or an electric heating device (74). The ultrasonic flow meter (8) includes a flow channel (81) and an ultrasonic transducer mounted on the flow channel (81); The position of the ultrasonic transducer in the radial direction of the flow channel (81) is adjustable. The ultrasonic transducer includes a sensor assembly (86). The position is adjustable to satisfy the following: the center of the end of the sensor assembly (86) near the axis of the flow channel (81) has a first state and a second state. The first state is that the center is located in the flow channel (81), and the second state is that the center is located on the inner wall boundary line (87) of the flow channel (81).

2. The gas flow metering device based on ultrasonic gas metering according to claim 1, characterized in that, A connecting seat (82) is provided on the flow channel (81); The ultrasonic transducer includes a transducer housing (85) and the sensor assembly (86) is mounted on the transducer housing (85). The connecting seat (82) is provided with an internal threaded hole, and the transducer housing (85) is a columnar structure with external threads on the outside. The transducer housing (85) is threadedly connected to the connecting seat (82): the transducer housing (85) is threadedly connected to the internal threaded hole through its external threads. It also includes an end plug (88) threaded into the internal threaded hole, in which the end plug (88) is located outside the ultrasonic transducer. The position of the ultrasonic transducer in the internal threaded hole is locked by the positive pressure exerted by the inner end face of the end plug (88) on the outer end face of the transducer housing (85).

3. The gas flow metering device based on ultrasonic gas metering according to claim 2, characterized in that, The internal threaded hole has a stepped surface facing outward from the internal threaded hole. The transducer housing (85) has a boss. An elastic support is held between the inner end face of the boss and the stepped surface. During the process of the transducer housing (85) penetrating the internal threaded hole and squeezing the elastic support, the elastic support undergoes compressive elastic deformation. In the first state and the second state, the elastic support is in a compressive elastic deformation state.

4. The gas flow metering device based on ultrasonic gas metering according to claim 1, characterized in that, A connecting seat (82) is provided on the flow channel (81); The ultrasonic transducer includes a transducer housing (85) and the sensor assembly (86) is mounted on the transducer housing (85). The connecting seat (82) is provided with a central hole, the central hole has a stepped surface facing outward from the central hole, the transducer housing (85) has a boss, the transducer housing (85) is embedded in the central hole, and an elastic support is held between the inner end face of the boss and the stepped surface. It also includes a clamping flange (84) and a first gasket (83), and a clamping screw for screwing the clamping flange (84) and the connecting seat (82); The clamping flange (84) fixes the ultrasonic transducer in the radial direction of the flow channel (81) by exerting force on the outer end face of the transducer housing (85) through its inner end face. The first pad (83) is used as follows: when the first pad (83) is clamped between the end face of the clamping flange (84) and the connecting seat (82), the second state is obtained; after removing the first pad (83) between the clamping flange (84) and the connecting seat (82) and tightening the clamping screw, the first state is obtained. During the process of the transducer housing (85) penetrating the central hole and pressing the elastic support, the elastic support undergoes compressive elastic deformation; in the first state and the second state, the elastic support is in a state of compressive elastic deformation.

5. The gas flow metering device based on ultrasonic gas metering according to claim 4, characterized in that, The transducer housing (85) is spaced apart from the hole wall of the central hole; A second gasket (89) is provided between the clamping flange (84) and the transducer housing (85), and the second gasket (89) is a gasket made of polymer material.

6. The gas flow metering device based on ultrasonic gas metering according to claim 5, characterized in that, The material of the second pad (89) is Teflon.

7. The gas flow metering device based on ultrasonic gas metering according to claim 5, characterized in that, The phase spacing is achieved by an axial sealing ring disposed between the wall of the central hole and the outer wall of the transducer housing (85).

Images