Circuit box structure and correlation type ultrasonic flowmeter

Abstract

The invention belongs to the technical field of flow metering equipment, particularly relates to a circuit box structure and a correlation type ultrasonic flowmeter, and aims to solve the problem that an existing circuit box structure cannot meet the five proposed requirements at the same time. According to the invention, a double-layer structure that a circular housing is sleeved on the outer side of a circular circuit box is adopted, a mode that a glass surface window is buckled on the surface of the circuit box instead of screws is adopted, and the circuit box independently bears arrangement and sealing of metering circuit devices; the circular shell can be directly clamped and fixed with the outer side of the circuit box through a buckle, and the circuit box is connected and fixed with an internal thread of a fixed seat in the middle of the metal flow tube only through a bolt; the appearance and the interior of the whole flowmeter are not fixed through screws, the flowmeter is convenient to maintain and not prone to being disassembled at will, the circuit box structure matched with the small-caliber correlation type ultrasonic flowmeter is formed, and the expected target is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of flow metering equipment, and specifically relates to a circuit box structure and a through-beam ultrasonic flow meter. Background Technology

[0002] In the era of the Internet of Things, big data, artificial intelligence, and industrial automation, fully electronic instruments are widely used in the fields of metering and measurement of industrial and public water, heat, and gas supply. The industry's requirements for the safe and reasonable circuit box structure of instruments and the improvement of their protection level have become important improvement issues.

[0003] In practical applications, to meet actual needs, the metrology industry provides the following five constraints on the circuit box performance of all-electronic small-diameter ultrasonic flow meters as a reference:

[0004] (I) Circuit box adaptation to the large range ratio requirement of ultrasonic flow meters: For the housing used in small-diameter ultrasonic flow meters, the flow meter should meet the requirement of a large range ratio. For example, for through-beam ultrasonic flow meters, the distance between the two transducers in the pipe should be maximized to achieve the maximum sound path, thereby maximizing the flow meter's range ratio. This is because the sound path of an ultrasonic flow meter is directly proportional to its range ratio, and the practical application of a large range ratio is very widespread. For example, in water metering, the large range ratio is a crucial indicator for trade settlement. To achieve a large range ratio in an ultrasonic flow meter, the two transducers of the ultrasonic water meter should be installed in a through-beam configuration, and the projected distance of the line connecting their distances in the direction of water flow in the main pipe should be maximized to obtain a large range ratio.

[0005] (II) The circuit box has a high protection level: Since the circuit box contains measuring or metering electronic components, heat insulation and waterproofing are crucial. Typically, circuit boxes are sealed with sealing rings. To overcome sealing failure caused by shell deformation, a circular shell is preferable, as this effectively mitigates sealing failure due to shell deformation. Furthermore, the method of fixing the shell, whether or not screws are used, should prevent the instrument box from loosening during use, which could reduce the protection level of the seals.

[0006] (iii) The circuit box should be impact-resistant and anti-aging: The circuit box should preferably be protected by an outer shell to be weather-resistant and adaptable to outdoor and environmental changes. The visible surface of the instrument should be anti-aging and preferably be made of glass.

[0007] (iv) The circuit box is not easy to disassemble at will: The accuracy of the measuring or metering instruments has been calibrated. Except for the lead seal that is allowed to be removed, other parts of the instrument box, such as the connection between the flow meter tube and the instrument, need to be well positioned and sealed, so they cannot be disassembled at will.

[0008] (v) The circuit box should facilitate the maintenance of electronic components: especially in complex industrial and mining sites, it should be easy to open the circuit box for maintenance and battery replacement after the lead seal is removed.

[0009] The installation methods and structural features of several existing instrument circuit boxes:

[0010] For example, patent announcement number CN 204788578 U provides a small-diameter through-beam conduit installation and its circuit box structure, as per its patent. Figure 1 As shown, in order to make the circuit box smaller, the two through-beam transducers are installed close to the middle of the pipeline. Although this reduces the size of the circuit box and facilitates sealing, thus meeting requirement (II), the distance between the two transducers is too close, which contradicts requirement (I), and the flowmeter has a relatively low range.

[0011] To improve the range ratio, the distance between transducers must be increased, as per authorization notice numbers CN 303646571 S and CN.

[0012] Applications such as 307158049S and CN 115900856 A provide small-diameter ultrasonic water meter housings. In order to meet the effect of requirement (I), the distance between the two transducers is increased, and the output end of the signal line is completely wrapped and protected by the housing. Therefore, the circuit box is large and has a rectangular structure, which increases the volume of the circuit box and makes sealing difficult, which is contrary to requirement (II).

[0013] Authorization announcement number CN 216309097 U is for an ultrasonic through-beam water meter with a DN15 signal line centrally led out, patent appendix Figure 1 The display shows that its pair of transducers, placed inside the pipe and installed in a through-beam configuration, meet the requirements of requirement (i), but from the patent appendix... Figure 6 It can be seen that the circuit box is square and easily deformed. In addition, the fixing and sealing methods of the upper shell of the circuit box are not marked, so it does not meet the requirements (II).

[0014] In summary, analysis of the existing circuit box structures of some small-diameter ultrasonic flowmeters reveals that, for structures where the transducer signal line is led out from the middle of the flowmeter tube, current technology cannot simultaneously meet requirements (i) to (v). Furthermore, almost all instruments using plastic circuit boxes rarely employ a glass surface as the visible surface; even when other transparent surfaces are used, they are mostly fixed with screws, posing durability issues. Therefore, current technology needs improvement and enhancement. Summary of the Invention

[0015] To address the aforementioned problems, this invention proposes a circuit box structure for use in through-beam ultrasonic flow meters. Specifically, for a structure where the transducer signal line is led out from the middle of the flow meter tube, it simultaneously meets requirements (i) to (v). The technical solution is as follows: A double-layer structure is adopted, with a circular outer shell surrounding a circular circuit box. Instead of screws, a glass window is used to snap the circuit box onto its surface, allowing the circuit box to independently house and seal the metering circuit components. A snap-fit ​​structure is provided between the circular outer shell and the circular circuit box, allowing the circular outer shell to be directly snapped and fixed by the circular circuit box. The circuit box is connected and fixed to the internal thread of the fixing seat in the middle of the metal flow tube using only one bolt. The entire flow meter, both externally and internally, is not fixed with screws and is not easily disassembled, thus forming a circuit box structure for a small-diameter through-beam ultrasonic flow meter. This structure simultaneously meets the five requirements proposed by the metering industry, achieving the expected goals.

[0016] This invention relates to a circuit box structure and a through-beam ultrasonic flow meter, comprising a metal outer tube, a fixing base, bolts, a bracket, an inner liner, a first conduit, a first insert, a transducer, an upper outer shell, a lower outer shell, a circuit box, a third protrusion, and a glass surface; the transducer is installed in a second hole of the bracket; the bracket is fitted into the inner liner; the first conduit is inserted into the third hole of the bracket; the upper outer shell is fitted onto the outside of the circuit box and fixed by a first protrusion that is caught under a second protrusion on the outside of the circuit box; the circuit box is composed of a rotating... The external thread of the bolt is connected and fixed to the internal thread of the fixing seat. At the same time, the bolt also penetrates into the positioning hole in the middle of the inner liner tube to fix the inner liner tube. A waterproof seal is installed on the glass surface at the opening of the circuit box. The second buckle under the outer shell is fastened to the first buckle on the outer shell. At the same time, the first blind hole post under the outer shell is tightly connected to the third protrusion post. The transducer signal line passes through the first conduit and extends out from the positioning hole to be electrically connected to the circuit board inside the circuit box, thereby constituting a circuit box and a through-beam ultrasonic flow meter that meet the above five requirements.

[0017] The transducer is tightly fitted into hole two on the bracket. Furthermore, the protrusion of the transducer is tightly fitted with curved surface one, and positioning surface six is ​​in contact with positioning surface three.

[0018] The bracket is fitted into the inner liner tube, and sealing rings two and three are respectively installed in two symmetrical grooves two and three in the middle of the outer side of the inner liner tube; furthermore, inserts two and three are respectively embedded in positioning grooves two and one; at the same time, the conduit one is tightly fitted into the hole three of the bracket, and is positioned by positioning surface four contacting positioning surface one.

[0019] The insert one is fitted tightly into the hole one on the bracket, and further, the positioning surface five contacts and positions itself with the positioning surface two.

[0020] The aforementioned protruding pillars are located on the outer side of the bottom surface of the circuit box, divided into two rows, spanning both sides of the metal outer tube. At the same time, the hollow pillar of the circuit box is fitted onto the outer side of the fixing seat, and the space between them is sealed by a sealing ring. The hollow pillar of the circuit box and the positioning hole of the inner liner tube at its lower end are fixed together by screwing bolts into the central hole of the fixing seat.

[0021] The glass surface is placed at the opening of the circuit box and is fastened by the convex edge three, positioned by the positioning surface seven, and sealed by the sealing ring four in the compression groove three; furthermore, the groove two divides the convex edge three into multiple segments, thereby giving the convex edge three the elasticity to expand outward.

[0022] The outer shell is fitted onto the outside of the circuit box, and is directly snapped onto the lower part of the circuit box by a first protrusion on the outer shell; furthermore, the first and second protrusions appear in pairs, and there can be multiple pairs.

[0023] The second buckle under the outer shell engages with the first buckle on the outer shell. At the same time, the first blind hole post under the outer shell extends into the middle hole of the third protrusion post and is tightly connected to it. Furthermore, the head of the blind hole post has a cross-shaped dividing groove to facilitate tight engagement with the third protrusion post.

[0024] The curved surface 2 at the middle of the outer side of the bottom surface of the circuit box contacts the outer side of the metal outer tube, and the contact surface is an arc-shaped fit with the same diameter as the metal outer tube.

[0025] In summary, compared with the prior art, the present invention has outstanding substantial improvements and significant progress, specifically manifested in the following ways:

[0026] First, it satisfies (i) the principle of maximizing sound path and the principle of through-beam installation: Since the technical solution adopted in this invention is to fix the transducer in the bracket and install it in the through-beam manner at both ends of the inner liner tube and place it in the metal outer tube, a wire passage is set through the docking of the bracket and the inner liner tube, so that the transducer signal line can be led out from the middle of the metal outer tube; therefore, for an ultrasonic flow meter given according to the standard length requirements, its pair of transducers can be embedded and placed at both ends of the pipe as much as possible without considering other installation factors. Therefore, the sound path can be maximized between a pair of transducers, that is, the maximum range ratio can be obtained.

[0027] Second, satisfying (ii) and (iii), the circuit box has a high level of protection and anti-aging properties: Since the circuit box used in this invention is placed inside the outer shell, the outer shell provides good protection and temperature isolation for it; In addition, the circuit box has a circular structure, and its lower end is sleeved with the outer side of the mounting seat in the middle of the metal outer tube, which is sealed by a sealing ring; the hollow column of the circuit box and the positioning hole of the inner liner tube at its lower end are fixed together by screwing the bolt into the middle hole of the fixing seat; at the upper end of the circular circuit box, the glass surface is pressed and sealed by a sealing ring four. The glass surface has good anti-aging properties, and the compression of the sealing ring four below it can be ensured by the extrusion of the convex edge three and the positioning of the positioning surface seven on the glass surface, so the sealing effect will not fail due to the deformation of the shell.

[0028] Third, it meets (iv) that the circuit box is not easy to disassemble at will: Since the outer shell is fixed by the internal circuit box, the bolts that fix the circuit box are inside the circuit box, and the upper and lower shells are connected by a snap-fit, plus the blind hole post under the shell goes into the three holes of the protrusion post in the circuit box and is tightly connected to it, and the upper and lower shells are sealed with lead, there are no screws or other places that can be disassembled from the appearance of the entire flow meter. Therefore, the instrument box cannot be disassembled at will.

[0029] Fourth, it meets (v), and the circuit components are easy to maintain: When the lead seal is removed, use a flathead screwdriver to pry open the bottom of the outer casing from the lead seal, and use an expander to expand from the bottom of the outer casing to remove the outer casing; then, use the expander to expand the upper convex edge of the circuit box to remove the glass surface, which makes it convenient to repair and replace the components inside the circuit box.

[0030] In summary, by implementing the technical solution of this invention, five principles can be satisfied simultaneously, ensuring performance, simple structure, convenient assembly, and low cost. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a circuit box structure and the appearance of a through-beam ultrasonic flow meter.

[0032] Figure 2 This is a cross-sectional view of a circuit box structure and a through-beam ultrasonic flow meter.

[0033] Figure 3 This is a schematic diagram of a circuit box structure and the housing of a through-beam ultrasonic flow meter.

[0034] Figure 4 This is a schematic diagram of a circuit box structure and a through-beam ultrasonic flow meter circuit box.

[0035] Figure 5 This is a schematic diagram of a circuit box structure and a transducer bracket insert for a through-beam ultrasonic flowmeter.

[0036] Figure 6A schematic diagram of a circuit box structure and a transducer support structure for a through-beam ultrasonic flowmeter. Figure 1 ;

[0037] Figure 7 A schematic diagram of a circuit box structure and a transducer support structure for a through-beam ultrasonic flowmeter. Figure 2 ;

[0038] Figure 8 It is an exploded view of the transducer bracket and its bracket inserts, and the transducer installation;

[0039] Figure 9 This is an exploded view of the transducer support assembly and inner liner tube installation.

[0040] Figure 10 It is a cross-sectional view of the transducer support assembly, inner liner tube, and outer metal tube during installation.

[0041] Figure 11 It is a partial sectional view of the metal outer tube, circuit box, and the upper and lower parts of the outer casing.

[0042] Figure 12 It is an exploded view of the installation on the outer casing, circuit box, metal outer tube, bolts, and under the outer casing.

[0043] In the picture:

[0044] 11. Metal outer tube; 112. External thread A; 113. External thread B; 13. Fixing base; 131. Sealing ring one; 132. Bolt; 133. Washer; 21. Bracket; 211. Fairing; 212. Insert two; 213. Insert three; 214. Positioning surface one; 215. Positioning surface two; 216. Hole one; 217. Hole two; 218. Positioning surface three; 219. Curved surface one; 22. Inner liner tube; 220. Hole three; 221. Hole four; 222. Positioning hole; 223. Sealing ring two; 224. Sealing ring three; 225. Positioning surface four; 226. Positioning groove one; 227. Positioning groove two; 228. Cable guide tube one; 229. Groove one; 230. Groove two; 24. Insert one; 241. Fixing Surface 5; 33. Transducer; 331. Protrusion; 332. Positioning Surface 6; 333. Lead wire; 41. Upper casing; 411. Protruding edge 1; 412. Protective edge; 413. Lead seal ring 1; 415. Buckle 1; 42. Lower casing; 421. Blind hole post 1; 4211. Blind hole post head; 422. Lead seal ring 2; 423. Buckle 2; 51. Circuit box; 511. Protruding edge 2; 512. Protruding post 1; 5121. Protruding post 2; 513. Protruding post 3; 5131. Groove 1; 514. Groove 3; 515. Protruding edge 3; 516. Groove 2; 517. Curved surface 2; 518. Hollow post; 519. Positioning Surface 7; 61. Glass surface; 62. Sealing ring 4; 63. Display screen; 64. Circuit board; 65. Battery. Detailed Implementation

[0045] The following detailed description, in conjunction with the accompanying drawings and examples, provides a further explanation of the circuit box structure and the implementation of the through-beam ultrasonic flow meter of the present invention.

[0046] Example 1:

[0047] As attached Figure 1 , 2 As shown, this embodiment is a circuit box structure and a DN15 through-beam ultrasonic water meter, including a metal outer tube 11, a fixing seat 13, a bolt 132, a bracket 21, an inner liner 22, a cable guide tube 228, an insert 24, a transducer 33, an upper outer shell 41, a lower outer shell 42, a circuit box 51, a protruding post 513, and a glass surface 61. The transducer 33 is installed in the second hole 217 of the bracket; the bracket 21 is fitted into the inner liner 22; the cable guide tube 228 is inserted into the third hole 220 of the bracket; the upper outer shell 41 is fitted onto the outside of the circuit box 51 and fixed by a protruding edge 411 that is secured below the protruding edge 511 on the outside of the circuit box; the circuit box 51 is fixed by the external thread of the bolt 132 being screwed into the internal thread of the fixing seat 13, and simultaneously, the bolt 132 also penetrates into the positioning hole 222 in the middle of the inner liner tube to secure the inner liner. The liner 22 is fixed; the glass surface 61 is pressed and installed at the opening of the circuit box 51 for waterproof sealing; the second buckle 423 of the lower shell 42 is fastened to the first buckle 415 of the upper shell 41, and at the same time, the blind hole post 421 of the lower shell 42 is inserted into the protruding post 513 for tight connection; the signal line 333 of the transducer 33 passes through the conduit 228, extends out from the positioning hole 222 and is electrically connected to the circuit board 64 inside the circuit box 51, thereby constituting a circuit box and a DN15 through-beam ultrasonic water meter that meet the above five requirements.

[0048] As attached Figure 7 , 8 As shown, the transducer 33 is embedded in the hole 217 on the bracket 21 and is tightly fitted, with epoxy resin applied between them for bonding. Furthermore, the protrusion 331 of the transducer is tightly fitted with the curved surface 219, and the positioning surface 332 is in contact with the positioning surface 218.

[0049] As attached Figure 7 , 9 As shown, the bracket 21 is fitted into the inner liner tube 22, and the two are bonded together with epoxy resin. The sealing ring 223 and the sealing ring 224 are respectively installed in the two symmetrical grooves 229 and 230 in the middle of the outer side of the inner liner tube 22. Furthermore, the inserts 212 and 213 are respectively embedded in the positioning grooves 227 and 226. At the same time, the conduit 228 is tightly fitted into the hole 220 of the bracket, and the two are bonded together with epoxy resin. The positioning surface 225 contacts and positions the conduit 214.

[0050] As attached Figure 5 , 6 As shown, the insert 24 is tightly fitted into the hole 216 on the bracket, and epoxy resin is applied between them for bonding. Furthermore, the positioning surface 241 contacts and positions the positioning surface 215.

[0051] As attached Figure 2 , 4 As shown in Figures 9 and 11, there are four convex pillars 513 on the outer side of the bottom surface of the circuit box 51, arranged in two rows, spanning both sides of the metal outer tube 11. At the same time, the hollow pillar 518 of the circuit box 51 is fitted onto the outer side of the fixing seat 13, and the space between them is sealed by a sealing ring 131. The hollow pillar 518 of the circuit box 51 and the positioning hole 222 of the inner liner tube 22 at its lower end are fixed together by screwing the bolt 132 into the central hole of the fixing seat 13.

[0052] As attached Figure 2 , 4 As shown, the glass surface 61 is placed at the opening of the circuit box 51, and is tightly fastened by the convex edge 3 515, positioned by the positioning surface 7 519, and sealed by the sealing ring 4 62 in the compression groove 3 514; furthermore, the groove 2 516 divides the convex edge 3 515 into multiple segments, thereby giving the convex edge 3 515 an outward expansion elasticity.

[0053] As attached Figure 2 , 3 As shown, the outer shell 41 is fitted onto the outside of the circuit box 51, and is directly snapped onto the lower part of the circuit box by the first protrusion 411 of the outer shell 41; furthermore, the first protrusion and the second protrusion appear in pairs, and there can be multiple pairs.

[0054] As attached Figure 11 , 12 As shown, the second buckle 423 of the lower shell 42 is engaged with the first buckle 415 of the upper shell 41. At the same time, the first blind hole post 421 of the lower shell is inserted into the middle hole of the third protrusion post 513 and is tightly connected to it. Furthermore, the blind hole post head 4211 has a cross-shaped dividing groove to facilitate tight fitting with the third protrusion post 513.

[0055] As attached Figure 4 As shown, the curved surface 517 at the middle of the outer side of the bottom surface of the circuit box 51 contacts the outer side of the metal outer tube 11, and the contact surface is an arc-shaped fit with the same diameter as the metal outer tube.

[0056] The assembly process of a DN15 through-beam ultrasonic water meter adapted to an equal-diameter transducer is as follows:

[0057] (1) As attached Figure 8 As shown, the transducer 33 is embedded into the hole 217 on the bracket 21 for tight fitting, and epoxy resin is applied between them for bonding. (2) As shown in the attached figure Figure 6 , 7As shown, the signal line 333 of the transducer 33 is passed through hole 221 and hole 216 of the bracket 21.

[0058] (3) As attached Figure 9 As shown, the bracket 21 is embedded with the rectifier tube 22, and epoxy resin is applied between them for bonding; sealing rings 223 and 224 are placed in two symmetrical grooves 229 and 230 in the middle of the outer side of the rectifier tube 22, respectively, and then the whole is put into the metal outer tube 11.

[0059] (4) As attached Figure 9 As shown, the signal line 333 of the transducer 33 passes through the second conduit 220 and the first conduit 221 and exits through the hole in the fixing base 13.

[0060] (5) As attached Figure 8 As shown, insert 24 is inserted into hole 216 on bracket 21 and tightly fitted, with epoxy resin applied between them for bonding.

[0061] (6) As attached Figure 12 As shown, the hollow column 518 in the center of the circuit box 51 is fitted on the outside of the fixing base 13 and sealed by a sealing ring. The hollow column 518 of the circuit box and the positioning hole 222 of the inner liner tube are fixed by screwing the bolt 132 into the central hole of the fixing base 13.

[0062] (7) As attached Figure 2 , 4 As shown, the circuit board 64 is fixed on the second protrusion 5121 of the circuit box and electrically connected to the signal line;

[0063] Place the battery 65 into the circuit box and connect it to the circuit board.

[0064] (8) As attached Figure 2 , 4 As shown, the sealing ring 62 is placed in the groove 514, and the glass surface 61 is pressed onto the opening of the circuit box.

[0065] (9) As attached Figure 2 , 4 As shown, the outer shell 41 is fitted onto the outside of the circuit box 51, and is fixed by directly snapping the outer shell 41 with the first protrusion 411 below the second protrusion 511 of the circuit box.

[0066] (10) As attached Figure 11 As shown, the second snap 423 of the lower shell 42 is engaged with the first snap 415 of the upper shell 41. At the same time, the first blind hole post 421 of the lower shell is inserted into the middle hole of the third protrusion post 513 and tightly connected with it.

[0067] (11) Snap the second buckle 423 of the lower shell 42 to the first buckle 414 of the upper shell. At the same time, the blind hole post 421 of the lower shell passes through the hole 123 of the fixing plate 12 and is tightly connected to it to complete the assembly.

[0068] It should be noted that, for ease of maintenance, an extender can be used to expand from the bottom of the outer casing to remove the outer casing; then, the extender can be used to expand the upper flange of the circuit box to remove the glass surface, which makes it easy to repair and replace the components inside the circuit box. After the flow meter is installed, the glass surface of the circuit box is protected by the outer casing flange and cannot be opened.

[0069] The above embodiments illustrate the application of the circuit box structure and through-beam ultrasonic flow meter of the present invention, as well as the application of the circuit box structure and DN15 through-beam ultrasonic water meter. However, the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the content of the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A circuit box structure and a through-beam ultrasonic flow meter, characterized in that: The device includes a metal outer tube (11), a fixing seat (13), bolts (132), a bracket (21), an inner liner (22), a first conduit (228), an insert (24), a transducer (33), an upper outer shell (41), a lower outer shell (42), a circuit box (51), a third protrusion (513), and a glass surface (61). The transducer (33) is installed in the second hole (217) of the bracket. The bracket (21) is connected to the inner liner (22). The first conduit (228) is inserted into the third hole (220) of the bracket. The upper outer shell (41) is fitted onto the outside of the circuit box (51) and fixed by the first protrusion (411) on the lower side of the second protrusion (511) on the outside of the circuit box. The circuit box (51) is secured by bolts (132) screwed into it. The external thread of 32) is connected and fixed to the internal thread of the fixing seat (13). At the same time, the bolt (132) is also inserted into the positioning hole (222) in the middle of the inner liner tube to fix the inner liner tube (22). The glass surface (61) can be snapped on at the opening of the circuit box (51) for waterproof sealing. The buckle 2 (423) of the lower shell (42) is snapped to the buckle 1 (415) of the upper shell (41). At the same time, the blind hole post 1 (421) of the lower shell (42) is inserted into the protrusion post 3 (513) for tight connection. The signal line (333) of the transducer (33) passes through the conduit 1 (228) and extends out from the positioning hole (222) to be electrically connected to the circuit board (64) in the circuit box (51), thereby constituting a circuit box and a through-beam ultrasonic flow meter that meet the above five requirements.

2. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The transducer (33) is embedded in the hole two (217) on the bracket (21) and fits tightly. Furthermore, the protrusion (331) of the transducer fits tightly with the curved surface one (219), and the positioning surface six (332) contacts and fits with the positioning surface three (218).

3. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The bracket (21) is fitted into the inner liner tube (22), and the sealing rings 2 (223) and 3 (224) are respectively installed in the two symmetrical grooves 2 (229) and 3 (230) in the middle of the outer side of the inner liner tube (22); further, the inserts 2 (212) and 3 (213) are respectively embedded in the positioning grooves 2 (227) and 1 (226); at the same time, the cable tube 1 (228) is tightly fitted into the hole 3 (220) of the bracket, and is positioned by the contact between the positioning surface 4 (225) and the positioning surface 1 (214).

4. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The insert (24) is fitted into the hole (216) on the bracket, and the positioning surface (241) contacts the positioning surface (215) for positioning.

5. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The aforementioned protruding column three (513) is located on the outer side of the bottom surface of the circuit box (51), divided into two rows, respectively spanning the two sides of the metal outer tube (11). At the same time, the hollow column (518) of the circuit box (51) is fitted on the outer side of the fixing seat (13), and the space between them is sealed by the sealing ring one (131). The hollow column (518) of the circuit box (51) and the positioning hole (222) of the lower end inner liner tube (22) are fixed together by screwing the bolt (132) into the middle hole of the fixing seat (13).

6. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The glass surface (61) is placed at the opening of the circuit box (51), and is fastened by the convex edge three (515), positioned by the positioning surface seven (519), and sealed by the sealing ring four (62) in the compression groove three (514); furthermore, the groove two (516) divides the convex edge three (515) into multiple segments.

7. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The outer shell (41) is fitted onto the outside of the circuit box (51), and is directly snapped onto the lower side of the second protrusion (511) of the circuit box by the first protrusion (411) of the outer shell (41); furthermore, the first protrusion and the second protrusion appear in pairs, and there can be multiple pairs.

8. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The buckle 2 (423) on the lower (42) of the outer shell is engaged with the buckle 1 (415) on the upper (41) of the outer shell. At the same time, the blind hole post 1 (421) on the lower (42) of the outer shell is inserted into the hole of the protruding post 3 (513) for tight connection. Furthermore, the blind hole post head (4211) has a cross-shaped dividing groove, which facilitates tight connection with the protruding post 3 (513).

9. The circuit box structure and through-beam ultrasonic flow meter according to claim 1, characterized in that: The curved surface 2 (517) in the middle of the outer side of the bottom surface of the circuit box (51) contacts the outer side of the metal outer tube (11), and the contact surface is an arc-shaped fit with the same diameter as the metal outer tube.

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