Small-diameter ultrasonic water meter pipe section structure and ultrasonic water meter

Abstract

This application discloses a pipe section structure for a small-diameter ultrasonic water meter and the ultrasonic water meter itself. The pipe section structure of the small-diameter ultrasonic water meter includes a pipe section body, a temperature sensor, and two ultrasonic sensors. Both ultrasonic sensors are installed on the same side of the pipe section body and are inclined along the side wall of the pipe section body. The temperature sensor is installed on the other side of the pipe section body and includes a housing, a resistance temperature detector (RTD) element, and a lead wire. The pipe section body has a mounting hole at the intersection of the extended acoustic axes of the two ultrasonic sensors. The housing is threaded into the mounting hole and has a reflective surface flush with the inner side wall of the pipe section body. The RTD element is encapsulated within the housing. One end of the lead wire is connected to the RTD element, and the other end is led out through a pre-set opening in the housing. The ultrasonic water meter includes this pipe section structure for the small-diameter ultrasonic water meter. This application embodiment has the advantages of reasonable structure, simplicity and practicality, convenient installation, reliable positioning, no reflector, few components, low pressure loss, and high measurement accuracy.

Description

Technical Field

[0001] This application relates to the field of ultrasonic water meter technology, and in particular to a small-diameter ultrasonic water meter pipe section structure and an ultrasonic water meter. Background Technology

[0002] Ultrasonic water meters, with their features of having no moving parts, ultra-low starting flow, low pressure loss, and low power consumption, are widely used in liquid metering and have gradually become the preferred instrument for measuring liquid media in pipelines. They represent a revolution in homogeneous liquid metering and are the development trend of the water meter industry.

[0003] In related technologies, the pipe section structure of a small-diameter ultrasonic water meter includes a pipe section body, two ultrasonic transducers, a temperature sensor, and a reflector. The two ultrasonic transducers are installed on the same side of the pipe section body, both inclined along the sidewall. The temperature sensor is installed between the two ultrasonic transducers on the same side of the pipe section body. The reflector can be in the form of a sheet or column, and is either inserted into or fixed within the pipe section body through a round hole, or fixed using inserts such as plastic bushings. The ultrasonic signal emitted by one ultrasonic transducer is reflected by the reflector and received by the other ultrasonic transducer. By analyzing the time difference caused by the change in velocity of the ultrasonic beam as it propagates upstream and downstream in the water flow, the flow velocity is obtained, and the flow rate is calculated.

[0004] However, the above-mentioned technical solutions have drawbacks such as numerous sensor components, complex structure, high precision requirements for assembling the reflector and pipe section, and large pressure loss. Therefore, there is an urgent need for a small-diameter ultrasonic water meter pipe section structure that is simple and practical in structure, easy and reliable in assembly, has low pressure loss, and high measurement accuracy. Summary of the Invention

[0005] To address at least one of the problems mentioned in the background art, embodiments of this application provide a pipe section structure for a small-diameter ultrasonic water meter and an ultrasonic water meter, which has the advantages of reasonable structure, simplicity and practicality, convenient installation, reliable positioning, no reflector, few components, low pressure loss, and high measurement accuracy.

[0006] To achieve the above objectives, the first aspect of this application provides a pipe section structure for a small-diameter ultrasonic water meter, including a pipe section body, a temperature sensor, and two ultrasonic sensors. Both ultrasonic sensors are installed on the same side of the pipe section and are arranged obliquely along the side wall of the pipe section; the extended lines of the acoustic axes of the two ultrasonic sensors intersect at the same point on the inner side wall of the pipe section. The temperature sensor is installed on the other side of the pipe section and includes a housing, a resistance temperature detector (RTD) element, and a lead wire. The pipe section has a mounting hole at the intersection of the extended acoustic axes of the two ultrasonic sensors, and the mounting hole penetrates at least through the side wall of the pipe section. The housing is threaded into the mounting hole and has a reflective surface flush with the inner side wall of the pipe section. The RTD element is encapsulated in the housing. One end of the lead wire is connected to the RTD element, and the other end is led out through a pre-set opening in the housing.

[0007] In one feasible implementation, a mounting protrusion is provided on the outer side wall of the pipe segment corresponding to the position of the mounting hole, and the mounting hole penetrates the mounting protrusion and the side wall of the pipe segment.

[0008] In one feasible implementation, the housing includes an insert section, a threaded section, a sealing ring, and a tightening section connected in sequence; Along the direction from near the central axis of the pipe segment to away from the central axis of the pipe segment, the mounting hole includes a plug hole and a threaded hole connected in sequence, and a sealing ring groove communicating with the threaded hole is opened at the port of the mounting hole away from the central axis of the pipe segment. The diameters of the plug hole, the threaded hole and the sealing ring groove increase in sequence. The insert section is inserted into the insert hole, the threaded section is threaded into the threaded hole, the sealing ring corresponds to the sealing ring groove, and a sealing ring is fitted around the outer circumference of the sealing ring. The sealing ring is embedded in the sealing ring groove, and the tightening section is pressed against the port of the mounting hole away from the central axis of the pipe section.

[0009] In one feasible implementation, the resistance temperature detector (RTD) element extends into the inner cavity of the housing through a pre-set opening in the tightening section, and sealant is injected between the RTD element and the housing. The end of the lead wire away from the RTD element is led out through the opening in the tightening section.

[0010] In one possible implementation, the housing is made of stainless steel, and the reflective surface is processed by a polishing process.

[0011] In one feasible implementation, the pipe section body is provided with an ultrasonic protrusion at the position where the ultrasonic sensor is installed, and the ultrasonic protrusion has an inclined ultrasonic mounting hole, the ultrasonic mounting hole including a stepped hole corresponding to the ultrasonic sensor. The ultrasonic sensor is installed in the stepped hole of the ultrasonic mounting hole, and the side wall of the ultrasonic sensor has an annular groove, and an O-ring is installed between the annular groove and the ultrasonic mounting hole. The ultrasonic mounting hole has an annular groove on the side of the ultrasonic sensor away from the central axis of the pipe section, and an elastic retaining ring for axial positioning of the ultrasonic sensor is embedded in the annular groove. The output line of the ultrasonic sensor is led out through a pre-set wire hole on the side wall of the ultrasonic protrusion; The annular groove is filled with sealant on the side of the ultrasonic sensor away from the central axis of the pipe section.

[0012] In one feasible implementation, a clamping cap is fitted onto the port of the ultrasonic mounting hole away from the central axis of the pipe section, and the sealant is located between the clamping cap and the ultrasonic sensor; The port of the ultrasonic mounting hole away from the central axis of the pipe section is provided with a retaining ring extending toward the center line of the ultrasonic mounting hole, and the inner diameter of the retaining ring is larger than the maximum diameter of the ultrasonic sensor. The clamping cap includes an end cap and hooks. The end cap has at least two circumferentially arranged hooks on the side facing the ultrasonic sensor. The hooks are engaged with the end face of the retaining ring near the ultrasonic sensor, and the end cap is pressed against the end face of the retaining ring away from the ultrasonic sensor.

[0013] In one feasible implementation, the angle between the extended acoustic axis of the ultrasonic sensor and the central axis of the pipe segment ranges from 30° to 60°.

[0014] A second aspect of this application provides an ultrasonic water meter, including the pipe section structure of the small-diameter ultrasonic water meter described above.

[0015] This application provides a pipe section structure for a small-diameter ultrasonic water meter and the ultrasonic water meter itself. The pipe section structure includes a pipe section body, a temperature sensor, and two ultrasonic sensors. Two ultrasonic sensors are installed on one side of the pipe section body, and a temperature sensor is installed on the other side at the intersection of the extended acoustic axes of the corresponding two ultrasonic sensors. The temperature sensor, while sensing temperature, also has a reflective surface on its outer shell. The ultrasonic signal from the ultrasonic sensor is reflected by the reflective surface and received by the other ultrasonic sensor, thereby calculating the water flow rate. This design eliminates the need for reflective elements and plastic bushings in the inner hole of the pipe section body, resulting in low water pressure loss. It also reduces the processing difficulty of key components and improves overall assembly accuracy, increasing production efficiency. This effectively improves the measurement accuracy of the small-diameter water meter while ensuring assembly accuracy. This application embodiment has the advantages of a reasonable overall structure, simple use, low cost, convenient assembly, and suitability for mass production. The ultrasonic water meter includes the aforementioned pipe section structure for a small-diameter ultrasonic water meter and has the same beneficial effects. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view of the pipe section structure of a small-diameter ultrasonic water meter provided in an embodiment of this application; Figure 2 for Figure 1 AA view; Figure 3 for Figure 1 Top view; Figure 4 An exploded view of the pipe section structure of a small-diameter ultrasonic water meter provided in this application embodiment; Figure 5 This is a schematic diagram of the structure of a temperature sensor provided in an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 100-pipe segment structure; 110 - Pipe section body; 111 - Mounting protrusion; 112 - Mounting hole; 113 - Ultrasonic protrusion; 114 - Wire hole; 115 - Ultrasonic mounting hole; 116 - Compression cap; 1161 - End cap; 1162 - Hook; 120 - Ultrasonic sensor; 121 - Output line; 130 - Temperature sensor; 131 - Housing; 1311 - Insert section; 1312 - Threaded section; 1313 - Sealing ring; 1314 - Tightening section; 1315 - Reflective surface; 132 - Resistance temperature detector (RTD) element; 133 - Lead wire; 140 - Sealant; 141 - Sealing ring; 142 - O-ring seal; 143 - Flexible retaining ring for holes. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. It is worth noting that the embodiments described in the accompanying drawings are only some embodiments of this application, and not all embodiments. That is, the embodiments described with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0020] The following will combine Figures 1-5 The pipe section structure 100 of the small-diameter ultrasonic water meter provided in the embodiments of this application will be described.

[0021] This application provides a pipe section structure 100 for a small-diameter ultrasonic water meter, referring to... Figures 1-4 As shown, it includes a pipe section 110, a temperature sensor 130, and two ultrasonic sensors 120.

[0022] Both ultrasonic sensors 120 are mounted on the same side of the pipe section 110 and are arranged obliquely along the side wall of the pipe section 110. The extended lines of the acoustic axes of the two ultrasonic sensors 120 intersect at a set point on the inner side wall of the pipe section 110.

[0023] Temperature sensor 130 is mounted on the other side of pipe section 110 and includes a housing 131, a resistance temperature detector (RTD) element 132, and a lead wire 133. A mounting hole 112 is provided on pipe section 110 at the intersection of the extended acoustic axes of the two ultrasonic sensors 120, and the mounting hole 112 penetrates at least through the sidewall of pipe section 110. Housing 131 is threaded into mounting hole 112 and has a reflective surface 1315 flush with the inner sidewall of pipe section 110. The RTD element 132 is encapsulated within housing 131. One end of lead wire 133 is connected to RTD element 132, and the other end is led out through a pre-designed opening in housing 131.

[0024] The ultrasonic sensor 120 includes an ultrasonic transducer. The extension line of the acoustic axis of the ultrasonic sensor 120 is the extension line of the central axis of the main acoustic beam of its ultrasonic wave, which is the same as the conventional meaning in the art. The output line 121 of the ultrasonic sensor 120 is electrically connected to the main board of the ultrasonic water meter to realize the transmission of ultrasonic signals between them.

[0025] The end of the temperature sensor 130 near the inner hole of the pipe section 110 is closed, and a reflective surface 1315 is machined on the side near the ultrasonic sensor 120. The reflective surface 1315 is flush with the inner wall of the inner hole of the pipe section 110. This flush arrangement is intended to allow the reflective surface 1315 to reflect and transmit signals between the two ultrasonic sensors 120. Theoretically, the reflective surface 1315 could be an arc-shaped structure that smoothly transitions to the inner wall. However, since the area of ​​the reflective surface 1315 of the temperature sensor 130 relative to the inner wall of the pipe section 110 is very small, the reflective surface 1315 can be a planar structure, with its center point corresponding to the intersection of the extended acoustic axes of the two ultrasonic sensors 120, and extending along the arc-shaped tangent of the inner wall at that intersection. The end of the temperature sensor 130 away from the inner hole of the pipe section 110 can be open. The lead wire 133 is led out through the open hole and used to electrically connect to the main board of the ultrasonic water meter, realizing the transmission of temperature signals between them.

[0026] In the two ultrasonic sensors 120, the ultrasonic signal of one ultrasonic sensor 120 is reflected by the reflective surface 1315 and received by the other ultrasonic sensor. By analyzing the time difference caused by the change in speed when the ultrasonic beam propagates in the water flow upstream and downstream, the flow velocity of the water flow is obtained, and then the flow rate of the water is calculated.

[0027] With this configuration, water flow can be measured without the need for a reflector inside the pipe section 110; the number of reflectors and plastic bushings is reduced, resulting in less water pressure loss; the processing difficulty of key components and the overall assembly precision are reduced, thus improving production efficiency.

[0028] The embodiments of this application can effectively improve the measurement accuracy of small-diameter water meters and effectively ensure assembly accuracy. They have the advantages of reasonable overall structure, simple use, low cost, convenient assembly, and suitability for mass production.

[0029] In one feasible implementation, refer to Figures 2-4 As shown, a mounting protrusion 111 is provided on the outer side wall of the pipe section 110 at the position corresponding to the mounting hole 112, and the mounting hole 112 penetrates the mounting protrusion 111 and the side wall of the pipe section 110.

[0030] In this way, the mounting hole 112 can be a hole that directly penetrates the side wall of the pipe section 110, or the depth of the mounting hole 112 can be increased by setting the mounting protrusion 111, so that the entire temperature sensor 130 can have a longer threaded connection with the pipe section 110, and the overall installation is more stable.

[0031] In one feasible implementation, refer to Figure 2 and Figure 5 As shown, the housing 131 includes an insert section 1311, a threaded section 1312, a sealing ring 1313, and a tightening section 1314 connected in sequence.

[0032] Along the direction from near the central axis of the pipe section 110 to away from the central axis of the pipe section 110, the mounting hole 112 includes a plug hole and a threaded hole connected in sequence, and a sealing ring groove communicating with the threaded hole is opened at the port of the mounting hole 112 away from the central axis of the pipe section 110. The diameters of the plug hole, the threaded hole and the sealing ring groove increase in sequence.

[0033] The insert section 1311 is inserted into the insert hole, the threaded section 1312 is threaded into the threaded hole, the sealing ring 1313 corresponds to the sealing ring groove, and the sealing ring 141 is sleeved on the outer circumference of the sealing ring 1313. The sealing ring 141 is embedded in the sealing ring groove, and the tightening section 1314 is pressed against the port of the mounting hole 112 away from the central axis of the pipe section body 110.

[0034] This design facilitates the insertion, threaded connection, and press-fitting of the housing 131, ensuring a good connection and seal between the temperature sensor 130 and the pipe section 110.

[0035] In one feasible implementation, refer to Figure 5 As shown, the thermal resistance element 132 extends into the inner cavity of the housing 131 through the pre-set opening of the tightening section 1314, and the thermal resistance element 132 and the housing 131 are filled with sealant 140, and the end of the lead wire 133 away from the thermal resistance element 132 is led out through the opening of the tightening section 1314.

[0036] The sealant 140 can be selected from silicone, epoxy resin, acrylic adhesive, etc., to achieve bonding and sealing between the thermal resistance element 132 and the housing 131. First, the thermal resistance element 132 is installed in the housing 131 of the temperature sensor 130, and the lead wire 133 is led out. Then, the sealant 140 is applied for potting. The end of the lead wire 133 away from the thermal resistance element 132 is electrically connected to the main board of the ultrasonic water meter.

[0037] In one possible implementation, the housing 131 is made of stainless steel, and the reflective surface 1315 is processed by a polishing process.

[0038] The outer shell 131 can be made of 316L stainless steel (06Cr17Ni12Mo2). The reflective surface 1315 is machined using a polishing machine, and its surface roughness must reach Ra≤0.08μm to meet the ultrasonic signal reflection requirements. To achieve a mirror finish on the reflective surface, the process begins with rough polishing: 80#-240# abrasive belts or fiber wheels are used to remove machining marks at a linear speed of 20~30m / s. Next, intermediate polishing is performed: 400#-800# sandpaper or nylon wheels are used for transition, with a pressure of 0.1~0.2MPa. Finally, fine polishing is performed: a wool wheel with chromium oxide paste (or 0.5μm diamond paste) is used at a speed of 2000~3000rpm. This achieves the final mirror finish. Cleaning is required after each process to avoid cross-contamination of abrasive materials.

[0039] In this way, by processing the outer shell 131, the temperature sensor 130 and the reflective surface 1315 are integrated, avoiding the use of a reflector inside the pipe section 110. This can still meet the requirements for flow measurement, reduce water pressure loss, and achieve higher measurement accuracy.

[0040] In one feasible implementation, refer to Figures 2-4 As shown, an ultrasonic protrusion 113 is provided on the pipe section 110 at the position where the ultrasonic sensor 120 is installed. The ultrasonic protrusion 113 has an inclined ultrasonic mounting hole 115. The ultrasonic mounting hole 115 is connected to the inner hole of the pipe section 110. The ultrasonic mounting hole 115 includes a stepped hole corresponding to the ultrasonic sensor 120.

[0041] The ultrasonic sensor 120 is installed in the stepped hole of the ultrasonic mounting hole 115, and the side wall of the ultrasonic sensor 120 has an annular groove. An O-ring 142 is installed between the annular groove and the ultrasonic mounting hole 115.

[0042] An annular groove is formed on the side of the ultrasonic sensor 120 away from the central axis of the pipe section 110 corresponding to the ultrasonic mounting hole 115. An elastic retaining ring 143 for axial positioning of the ultrasonic sensor 120 is embedded in the annular groove.

[0043] The output line 121 of the ultrasonic sensor 120 is led out through the wire hole 114 pre-set on the side wall of the ultrasonic protrusion 113.

[0044] Sealant 140 is injected into the side of the annular groove corresponding to the ultrasonic sensor 120 away from the central axis of the pipe section 110.

[0045] Similarly, the ultrasonic protrusion 113 increases the depth of the ultrasonic mounting hole 115, facilitating the stable installation of the ultrasonic sensor 120. The ultrasonic sensor 120 has a stepped columnar structure that is smaller at the bottom and larger at the top, and is installed in the middle of the ultrasonic mounting hole 115. A certain distance is maintained between the inner end of the ultrasonic sensor 120 and the inner wall of the pipe section 110. An annular groove is provided on the inner wall of the ultrasonic mounting hole 115 at the outer end of the ultrasonic sensor 120. The hole installed in the annular groove is limited by an elastic retaining ring 143 to restrict the axial movement of the ultrasonic sensor 120. The outer end of the annular groove has space for injecting sealant 140 and installing the clamping cap 116 described below.

[0046] In one feasible implementation, refer to Figure 2 and Figure 4 As shown, the ultrasonic mounting hole 115 is fitted with a clamping cap 116 at the port away from the central axis of the pipe section 110, and the sealant 140 is located between the clamping cap 116 and the ultrasonic sensor 120.

[0047] A retaining ring is provided at the port of the ultrasonic mounting hole 115 away from the central axis of the pipe section 110, extending towards the center line of the ultrasonic mounting hole 115. The inner diameter of the retaining ring is larger than the maximum diameter of the ultrasonic sensor 120.

[0048] The clamping cover 116 includes an end cover 1161 and hooks 1162. At least two hooks 1162 arranged circumferentially are provided on the side of the end cover 1161 facing the ultrasonic sensor 120. The hooks 1162 are engaged with the end face of the retaining ring near the ultrasonic sensor 120. The end cover 1161 is pressed against the end face of the retaining ring away from the ultrasonic sensor 120.

[0049] The retaining ring folds back towards the center of the ultrasonic mounting hole 115. The ultrasonic sensor 120 passes through the retaining ring and is installed at the step of the ultrasonic mounting hole 115. After the sealant 140 is injected, the clamping cover 116 is installed by the retaining ring secured by the hook 1162. The clamping cover 116 can be made of a plastic material with a certain degree of elasticity. The clamping cover 116 further fixes and tightens the ultrasonic sensor 120, improving its installation stability.

[0050] During installation, firstly, an O-ring 142 is fitted onto the ultrasonic sensor 120 and clamped tightly into the stepped hole of the ultrasonic mounting hole 115. Then, an elastic retaining ring 143 is embedded in the annular groove to prevent axial movement of the ultrasonic sensor 120. Next, the output wire 121 is led out from the wire hole 114, and sealant 140 is injected into the ultrasonic mounting hole 115. Finally, after the sealant 140 has cured, the clamping cap 116 is installed, pressing the sealant 140 firmly against it.

[0051] In one feasible implementation, the angle between the extended acoustic axis of the ultrasonic sensor 120 and the central axis of the pipe section 110 is in the range of 30°-60°.

[0052] In this way, the ultrasonic sensors 120 can be installed symmetrically, and the installation angle of the ultrasonic sensors 120 can be selected according to actual needs.

[0053] The ultrasonic water meter provided in the embodiments of this application will be described below.

[0054] This application provides an ultrasonic water meter, including the pipe section structure 100 of the small-diameter ultrasonic water meter described above.

[0055] This ultrasonic water meter is especially suitable for household metering applications. It can effectively improve the measurement accuracy of small-diameter water meters and ensure assembly accuracy. It has the advantages of reasonable overall structure, simple use, low cost, convenient assembly, and suitability for mass production.

[0056] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" in the description of this application should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0057] The terms “upper,” “lower,” “front,” “back,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0058] The term "multiple" means two or more, unless otherwise specified precisely.

[0059] The terms “first,” “second,” “third,” “fourth,” etc., (if applicable) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can include implementations in sequences other than those illustrated or described herein.

[0060] The terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A pipe section structure of a small-bore ultrasonic water meter, characterized by, Includes the pipe section, temperature sensor, and two ultrasonic sensors; Both ultrasonic sensors are installed on the same side of the pipe section and are arranged obliquely along the side wall of the pipe section; the extended lines of the acoustic axes of the two ultrasonic sensors intersect at the same point on the inner side wall of the pipe section. The temperature sensor is installed on the other side of the pipe section and includes a housing, a thermal resistance element, and leads; the pipe section has a mounting hole at the intersection of the extended acoustic axes of the two ultrasonic sensors, and the mounting hole penetrates at least through the side wall of the pipe section; the housing is threaded into the mounting hole, and the housing has a reflective surface flush with the inner side wall of the pipe section; The resistance temperature detector (RTD) element is encapsulated within a housing; one end of the lead wire is connected to the RTD element, and the other end is led out through a pre-set opening in the housing.

2. The pipe section structure of a small-bore ultrasonic water meter according to claim 1, characterized in that, The outer side wall of the pipe segment is provided with a mounting protrusion corresponding to the position of the mounting hole, and the mounting hole penetrates the mounting protrusion and the side wall of the pipe segment.

3. The pipe section structure of a small-bore ultrasonic water meter according to claim 1, characterized in that, The housing includes an insert section, a threaded section, a sealing ring, and a tightening section connected in sequence; Along the direction from near the central axis of the pipe segment to away from the central axis of the pipe segment, the mounting hole includes a plug hole and a threaded hole connected in sequence, and a sealing ring groove communicating with the threaded hole is opened at the port of the mounting hole away from the central axis of the pipe segment. The diameters of the plug hole, the threaded hole and the sealing ring groove increase in sequence. The insert section is inserted into the insert hole, the threaded section is threaded into the threaded hole, the sealing ring corresponds to the sealing ring groove, and a sealing ring is fitted around the outer circumference of the sealing ring. The sealing ring is embedded in the sealing ring groove, and the tightening section is pressed against the port of the mounting hole away from the central axis of the pipe section.

4. The pipe section structure of a small-bore ultrasonic water meter according to claim 3, characterized in that, The resistance temperature detector (RTD) element extends into the inner cavity of the housing through a pre-set opening in the tightening section, and sealant is injected between the RTD element and the housing. The end of the lead wire away from the RTD element is led out through the opening in the tightening section.

5. The pipe section structure of a small-bore ultrasonic water meter according to any one of claims 1 to 4, characterized in that, The outer casing is made of stainless steel, and the reflective surface is processed by a polishing process.

6. The pipe section structure of the small-diameter ultrasonic water meter according to any one of claims 1-4, characterized in that, The pipe section is provided with an ultrasonic protrusion at the position where the ultrasonic sensor is installed. The ultrasonic protrusion has an inclined ultrasonic mounting hole, which includes a stepped hole corresponding to the ultrasonic sensor. The ultrasonic sensor is installed in the stepped hole of the ultrasonic mounting hole, and the side wall of the ultrasonic sensor has an annular groove, and an O-ring is installed between the annular groove and the ultrasonic mounting hole. The ultrasonic mounting hole has an annular groove on the side of the ultrasonic sensor away from the central axis of the pipe section, and an elastic retaining ring for axial positioning of the ultrasonic sensor is embedded in the annular groove. The output line of the ultrasonic sensor is led out through a pre-set wire hole on the side wall of the ultrasonic protrusion; The annular groove is filled with sealant on the side of the ultrasonic sensor away from the central axis of the pipe section.

7. The pipe section structure of a small-bore ultrasonic water meter according to claim 6, characterized in that, The ultrasonic mounting hole is fitted with a clamping cap at the port furthest from the central axis of the pipe section, and the sealant is located between the clamping cap and the ultrasonic sensor. The port of the ultrasonic mounting hole away from the central axis of the pipe section is provided with a retaining ring extending toward the center line of the ultrasonic mounting hole, and the inner diameter of the retaining ring is larger than the maximum diameter of the ultrasonic sensor. The clamping cap includes an end cap and hooks. The end cap has at least two circumferentially arranged hooks on the side facing the ultrasonic sensor. The hooks are engaged with the end face of the retaining ring near the ultrasonic sensor, and the end cap is pressed against the end face of the retaining ring away from the ultrasonic sensor.

8. The pipe section structure of a small-bore ultrasonic water meter according to any one of claims 1 to 4, characterized in that, The angle between the extended acoustic axis of the ultrasonic sensor and the central axis of the pipe section ranges from 30° to 60°.

9. An ultrasonic water meter characterized by, The pipe section structure includes that of a small-diameter ultrasonic water meter as described in any one of claims 1-8.

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