Flowmeter Structure and Installation and Adjustment Method for Reducing the Calibration Workload of Straight Tube Density Meters

Abstract

This application relates to the technical field of straight-tube densitometer calibration, and specifically discloses a flowmeter structure and installation and adjustment method for reducing the calibration workload of straight-tube densitometers. The flowmeter structure includes a flow tube, a magnet fixing seat, a sleeve, an adjusting screw, and a gasket. The magnet fixing seat is fixedly surrounded outside the flow tube. The magnet fixing seat has an internal threaded hole. The sleeve is sleeved outside the magnet fixing seat and a section of the flow tube. Both ends of the sleeve are fixed to the flow tube. The outer wall of the sleeve has a mounting surface and a mounting hole. The gasket is fitted to the mounting surface. The adjusting screw passes through the gasket and the mounting hole and is inserted into the internal threaded hole. By changing the depth of the adjusting screw screwed into the magnet fixing seat, the fundamental frequency of the flow tube is adjusted. When producing the same batch of straight-tube densitometers, each flowmeter is adjusted to have the same fundamental frequency, and only one flowmeter is measured for multiple fluid media to obtain multiple correction factors, and the obtained multiple correction factors are input into other flowmeters, significantly reducing the calibration workload.

Description

Technical Field

[0001] The present application relates to the technical field of rectifiers, and in particular to a flow meter structure and an adjustment method for reducing the calibration workload of a straight tube density meter. Background Art

[0002] When the fluid flows in a stable and stimulated pipe, it will generate a Coriolis force proportional to the mass flow rate. Compared with ultrasonic and thermal methods, it realizes the direct measurement of fluid mass flow rate, density and other parameters with high precision in the true sense. When the flow tube and the fluid move relative to each other, that is, the fluid flows in the flow tube, the response of the flow tube structure will be different. The vibration phase at the input end will lag behind the drive phase, while the vibration phase at the output end will lead the drive phase. The difference between the sinusoidal signals on the input and output sides is proportional to the mass flow rate and density. In order to obtain a stable phase difference and to reduce energy input loss, the flow tubes all work at their own natural frequency. In order to adapt to different fluid media, the flow meter is accompanied by calibration of various media during the assembly process, such as empty pipe calibration, water medium calibration, alcohol medium calibration, etc., to obtain correction coefficients to guide the flow meter measurement correction.

[0003] The calibration process occupies most of the workload of flow meter installation and adjustment, especially when batch-installing the same type of flow meters, it is necessary to repeatedly calibrate the correction coefficient of each flow meter under each medium, which is a lot of work. Therefore, reducing the calibration workload of flow meters in the same batch is of great significance to improving the market competitiveness of products.

[0004] For a precision device such as a straight tube density meter, the flow tube is usually a relatively sensitive component, which is affected by a series of factors such as its own tube size distribution, material property discreteness, molding process, and additional mass of the measurement circuit. Therefore, its natural frequency has a certain degree of discreteness. The existence of individual fundamental frequency differences not only reduces the consistency of mass flow meter batches, but also reduces the reliability of the product.

[0005] Traditionally, there are corresponding control measures in material selection, design, and manufacturing, such as consistency control of raw materials for pipes, measurement circuit layout and optimization, and the molding process relying on special tooling. However, the above measures increase costs while improving the frequency consistency of the same batch of flow meters, which in turn reduces the market competitiveness of the products. Summary of the invention

[0006] Based on the problem that the existence of individual fundamental frequency differences of the same type of mass flow meter reduces the consistency of mass flow meter batches and also reduces the reliability of the product, this application proposes the following solution.

[0007] In a first aspect, the present application proposes a flow meter structure that reduces the calibration workload of a straight tube density meter, and adopts the following technical solution.

[0008] A flowmeter structure for reducing the calibration workload of a straight-tube densitometer, comprising a flow tube, a magnet fixing seat, a sleeve, an adjusting screw and a gasket.

[0009] The magnet fixing seat is fixedly surrounded outside the flow tube. The magnet fixing seat has a radial internal threaded hole. The sleeve is sleeved outside the magnet fixing seat and a section of the flow tube. Both ends of the sleeve are fixed to the outer wall of the flow tube.

[0010] The outer wall of the sleeve has a mounting surface, and the sleeve also has a mounting hole penetrating from the mounting surface to the inner wall of the sleeve. The gasket has an adjusting hole. The gasket fits the mounting surface, enabling the adjusting hole and the mounting hole to be concentrically aligned. The adjusting screw passes through the adjusting hole and the mounting hole, and is inserted into the internal threaded hole and threadedly connected thereto in an adapted manner, so that the gasket, the sleeve and the flow tube are fixed to each other.

[0011] By adopting the above technical solution, the adjusting screw connects the gasket, the sleeve and the magnet fixing seat in series, and the magnet fixing seat is fixed to the flow tube. Thus, the fundamental frequency of the flow tube can be adjusted by changing the depth of the adjusting screw screwed into the magnet fixing seat. When producing the same batch of straight-tube densitometers, components of the same specification are used. By moderately adjusting the depth of the adjusting screw screwed into the magnet fixing seat, each flowmeter can be adjusted to have the same fundamental frequency. For flowmeters with the same fundamental frequency, multiple correction factors can be obtained by measuring one flowmeter for multiple fluid media, and the obtained multiple correction factors can be input into other flowmeters for use, without the need to test other flowmeters for multiple fluid media to obtain multiple correction factors, significantly reducing the calibration workload, and improving both the consistency of the straight-tube densitometer batch and the reliability of the straight-tube densitometer.

[0012] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight-tube densitometer is that both the adjusting hole and the mounting hole are circular holes. The aperture of the adjusting hole is 2 - 4 mm larger than the rod diameter of the adjusting screw. The aperture of the mounting hole is 2 - 4 mm larger than the rod diameter of the adjusting screw.

[0013] By adopting the above technical solution, the gaps between the adjusting screw and the adjusting hole and the mounting hole facilitate the fine adjustment of the adjusting screw in the front, back, left and right directions, reducing the requirement for the initial position accuracy of the screw fixing seat.

[0014] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight-tube densitometer is that the mounting surface is a flat surface. The surface of the adjusting screw in contact with the gasket is a flat surface. The adjusting screw and the gasket are in flat contact. The gasket and the mounting surface are in flat contact.

[0015] By adopting the above technical solution, the connection structure of the adjusting screw, gasket and sleeve is stable, avoiding the unstable defect of the contact between the adjusting screw and the arc surface of the sleeve.

[0016] A preferred embodiment of the flowmeter structure for reducing the calibration workload of the straight tube densitometer is that the gasket further has a plurality of external threaded holes. The sleeve further has a plurality of middle threaded holes penetrating from the mounting surface to the inner wall of the sleeve. The flowmeter structure further includes a plurality of connecting screws. Each of the connecting screws passes through one of the external threaded holes and one of the middle threaded holes to fix the gasket to the sleeve.

[0017] By adopting the above technical solution, this setting strengthens the connection stability between the gasket and the sleeve.

[0018] A preferred embodiment of the flowmeter structure for reducing the calibration workload of the straight tube densitometer is that the outer wall surface of the magnet fixing seat has two inner fixing planes that are symmetric and parallel, and inner magnet fixing holes penetrating from the inner fixing planes to the inner wall surface of the magnet fixing seat; the sleeve has two symmetric middle magnet fixing holes; when the inner threaded holes are aligned with the mounting holes, the two inner magnet fixing holes are aligned with the two middle magnet fixing holes.

[0019] By adopting the above technical solution, the magnet fixing seat and the sleeve can be used to fix the magnet of the sensor for measuring the fundamental frequency of the flow tube.

[0020] A preferred embodiment of the flowmeter structure for reducing the calibration workload of the straight tube densitometer is that the outer wall of the sleeve has two symmetric and parallel mounting surfaces, and each mounting surface is provided with the mounting hole; the outer wall of the sleeve further has two middle fixing planes, and each middle fixing plane is provided with one of the middle magnet fixing holes; the two mounting surfaces are perpendicular to the two middle fixing planes.

[0021] By adopting the above technical solution, there are many optional orientations for the mutual alignment of the magnet fixing seat and the sleeve, which is convenient for the rotational alignment of the magnet fixing seat in the sleeve.

[0022] A preferred embodiment of the flowmeter structure for reducing the calibration workload of the straight tube densitometer is that the inside of the sleeve has a cylindrical main cavity and two cylindrical enlarged cavities. The two enlarged cavities communicate with both ends of the main cavity, and the diameter of the enlarged cavity is larger than that of the main cavity, so that a stepped annular surface is formed at the connection of each end of the main cavity and the enlarged cavity.

[0023] The flowmeter structure further includes two outer ring blocks and two inner ring blocks. One of the outer ring blocks is installed in each of the expansion cavities, and one of the inner ring blocks is installed in each of the outer ring blocks. The outer peripheral surface of the outer ring block is fixedly attached to the inner peripheral surface of the expansion cavity, and the inner end surface of the outer ring block is attached to the stepped ring surface. The inner peripheral surface of each outer ring block is frustum-shaped, with the smaller end facing inward and the larger end facing outward. The outer peripheral surface of the inner ring block is frustum-shaped, with the smaller end facing inward and the larger end facing outward. The outer peripheral surface of the inner ring block is attached to the inner peripheral surface of the outer ring block. The inner peripheral surface of the inner ring block is cylindrical and is fixedly attached to the flow tube.

[0024] By adopting the above technical solution, the mechanism facilitates the rotation of the flow tube and does not lose its position during rotation, facilitating the alignment of the internal threaded hole of the magnet fixed seat and the installation hole of the sleeve, and enabling welding fixation after alignment.

[0025] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight tube densitometer is that the inclination angle of the outer peripheral surface of the inner ring block is 10° - 15°.

[0026] By adopting the above technical solution, during assembly, the outer peripheral surface of the inner ring block with this inclination angle presses against the outer ring block to achieve positioning and pre-tightening. This method increases the connection boundary stiffness and better ensures the consistency of the fundamental frequency of the flowmeter structure in mass production.

[0027] In a second aspect, the present application proposes an installation and adjustment method for a flowmeter structure for reducing the calibration workload of the straight tube densitometer, and adopts the following technical solutions.

[0028] An installation and adjustment method for a flowmeter structure for reducing the calibration workload of the straight tube densitometer as described above, the installation and adjustment method includes:

[0029] S1, sleeving the magnet fixed seat outside the flow tube and fixing them to each other.

[0030] S2, inserting the mutually fixed flow tube and magnet fixed seat into the sleeve.

[0031] S3, installing the outer ring blocks at both ends of the sleeve respectively, and then installing the inner ring blocks in each of the outer ring blocks.

[0032] S4, applying an inward thrust to each of the inner ring blocks, so that the inner ring blocks push against the outer ring blocks, causing the inner end surface of the outer ring blocks to abut against the stepped ring surface, and the outer wall surface of the outer ring blocks to closely fit the inner wall surface of the sleeve.

[0033] S5, rotating the flow tube so that the internal threaded hole aligns with the installation hole.

[0034] S6, while maintaining the inward thrust applied to each of the inner ring blocks, weld and fix the contact gaps between the outer ring block and the casing and between the inner ring block and the flow tube, and then release the inward thrust applied to the inner ring blocks.

[0035] S7, Place the gasket on the mounting surface so that the adjustment hole aligns with the mounting hole.

[0036] S8, Insert the adjustment screw through the adjustment hole, the mounting hole and screw it into the internal thread hole. Adjust the fundamental frequency of the flow tube by rotating the adjustment screw, and at the same time detect the fundamental frequency of the flow tube during the screwing process so that the fundamental frequency of the flow tube reaches the set value, obtaining one structure of the flowmeter.

[0037] S9, Calibrate the measurement performance of the flowmeter structure obtained in S8 under various media to obtain the correction coefficients for each medium.

[0038] S10, When assembling and adjusting the flowmeter structures of the same batch, repeat steps S1 - S8 to obtain several flowmeter structures with equal fundamental frequencies. For each obtained flowmeter structure, input the correction coefficients for each medium obtained in step S9 into each flowmeter structure, and repeat to complete the batch assembly and adjustment of the flowmeter structures of the same batch.

[0039] By adopting the above technical solution, the batch - manufactured flowmeters have consistent fundamental frequencies and reduce the calibration workload of the flowmeters.

[0040] A preferred solution for the assembly and adjustment method of the flowmeter structure for reducing the calibration workload of the straight - tube densitometer is that in step S8, after the fundamental frequency of the flow tube reaches the set value, continue to tighten the adjustment screw by three turns.

[0041] By adopting the above technical solution, this method applies a pre - tightening force to enhance the reliability of the connection.

[0042] In summary, the flowmeter structure and the assembly and adjustment method for reducing the calibration workload of the straight - tube densitometer of the present application have the following beneficial effects: By designing the connection form of the adjustment screw between the casing and the magnetic steel fixing seat, the fundamental frequency of the flowmeter can be finely adjusted by adjusting the depth of the adjustment screw. When manufacturing the same batch of flowmeters, the fundamental frequency of each flowmeter can be adjusted to the same target value. On this basis, by measuring the measurement performance of one flowmeter under multiple media, calibration is carried out to obtain the correction coefficients for each medium, and input these correction coefficients for each medium into other flowmeters manufactured in the same batch. Other flowmeters manufactured in the same batch are exempt from testing the measurement performance calibration under various media, reducing the calibration workload, lowering the cost, and enhancing the market competitiveness. Description of the Drawings

[0043] Figure 1 It is a sectional internal structure diagram of a flowmeter structure for reducing the calibration workload of a straight-tube densitometer.

[0044] Figure 2 It is a schematic diagram of the flow tube.

[0045] Figure 3 It is a structure diagram of the magnet fixing seat.

[0046] Figure 4 It is a sectional internal structure diagram of the casing.

[0047] Figure 5 It is an external structure diagram of the casing.

[0048] Figure 6 It is a structure diagram of the gasket.

[0049] Figure 7 It is a schematic diagram of the pre-tightening connection of the outer ring block and the inner ring block.

[0050] Reference numerals: 1, flow tube; 4, magnet fixing seat; 3, casing; 5, adjusting screw; 6, gasket; 2, outer ring block; 7, inner ring block; 401, inner fixing plane; 402, inner magnet fixing hole; 403, inner threaded hole; 302, mounting surface; 305, middle fixing plane; 304, mounting hole; 303, middle threaded hole; 306, middle magnet fixing hole; 602, adjusting hole; 601, outer threaded hole; 603, circular plane; 301, stepped ring surface; 307, main cavity; 308, enlarged cavity; 201, first contact gap; 701, second contact gap. Detailed implementation manners

[0051] Next, the technical solutions in the embodiments will be described clearly and completely with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the following embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0052] Reference Figure 1 , a flowmeter structure for reducing the calibration workload of a straight-tube densitometer, includes a flow tube 1, a magnet fixing seat 4, a casing 3, an adjusting screw 5, a gasket 6, four connecting screws (not shown in the figure), two outer ring blocks 2 and two inner ring blocks 7.

[0053] As Figure 2 , the flow tube 1 is a thin round tube.

[0054] As Figure 3, the magnet fixing base 4 is an annular column, which is tightly sleeved outside the flow tube 1 and can be fixed by welding. There are two symmetrical inner fixing planes 401 on both sides of the outer circumference of the magnet fixing base 4, and the two inner fixing planes 401 are parallel to each other. The magnet fixing base 4 also has two radial inner magnet fixing holes 402 and one radial inner threaded hole 403. Each inner magnet fixing hole 402 penetrates from one inner fixing plane 401 to the inner ring surface of the magnet fixing base 4, which is convenient for installing the magnet and abutting against the flow tube 1 to test the fundamental frequency of the flow tube 1. The inner threaded hole 403 also penetrates from the outer circumference of the magnet fixing base 4 to the inner ring surface of the magnet fixing base 4, and it is perpendicular to the connection line of the two inner magnet fixing holes 402.

[0055] The sleeve 3 is sleeved outside the magnet fixing base 4 and the flow tube 1. An outer ring block 2 and an inner ring block 7 are installed at each end of the sleeve 3 and fixed to the flow tube 1 by welding, but both ends of the flow tube 1 extend outside the inner ring block 7. Before welding, the alignment of the inner threaded hole 403 and the sleeve 3 is also required.

[0056] As Figure 4 , the outer wall of the sleeve 3 has two symmetrical and parallel mounting surfaces 302 and two symmetrical and parallel middle fixing planes 305. The mounting surface 302 is also a plane, and the mounting surface 302 and the fixing surface are perpendicular to each other and are both recessed within the outer circular wall of the sleeve 3. An installation hole 304 is opened on each mounting surface 302, and the installation hole 304 penetrates through the pipe wall of the sleeve 3. Only one installation hole 304 is aligned with the inner threaded hole 403.

[0057] As Figure 5 , four middle threaded holes 303 are also opened on the mounting surface 302, and they are distributed on the periphery of the installation hole 304. A middle magnet fixing hole 306 is opened on each middle fixing plane 305, which is aligned with the two inner magnet fixing holes 402 and is used for the magnet to pass through and be fixed, so as to use the magnet to test the fundamental frequency of the flow tube 1. The magnet is not shown in the drawings. The magnet in the sensor for testing the fundamental frequency of the flow tube 1 passes through the middle magnet fixing hole 306 and the inner magnet fixing hole 402 and abuts against the flow tube 1, so that the sensor can measure the fundamental frequency of the flow tube 1.

[0058] As Figure 6 , the gasket 6 is a flat cylindrical shape, with an end face being a circular plane 603, and there are five holes on it, namely the central adjustment hole 602 and four outer threaded holes 601. The four outer threaded holes 601 are located on the periphery of the adjustment hole 602. The adjustment hole 602 is aligned with the installation hole 304 and the inner threaded hole 403. The four outer threaded holes 601 are aligned with the four middle threaded holes 303 one by one, and four connecting screws (not shown in the drawings) are used for connection to fix the gasket 6 to the sleeve 3. It should be noted that: Figure 6The four external threaded holes 601 are shown as a random arrangement structure, which can be arranged in a circumferentially equidistant structure, so that the four external threaded holes 601 and Figure 5 the four middle threaded holes 303 are in one-to-one alignment; the positions of the four external threaded holes 601 and the four middle threaded holes 303 can be randomly arranged as long as they can achieve one-to-one alignment, but preferably as in Figure 5 the circumferentially equidistant arrangement.

[0059] The mounting surface 302 is a plane, but its outer periphery can be circular and matches the outer periphery of the gasket 6. Then the gasket 6 fits on the mounting surface 302, and the gasket 6 can be restricted by the sleeve 3 within the mounting surface 302. No matter how the gasket 6 is rotated, the adjustment hole 602 at the center of the gasket 6 is accurately aligned with the mounting hole 304 on the sleeve 3.

[0060] The adjusting screw 5 is used to pass through the adjusting hole 602 and the mounting hole 304 and insert into the internal threaded hole 403 for threaded connection. The adjusting hole 602 and the mounting hole 304 can be round holes. To facilitate the alignment of the internal threaded hole 403 with the adjusting hole 602 and the mounting hole 304, in this solution, the diameter of the adjusting hole 602 is 2 - 4 mm larger than the rod diameter of the adjusting screw 5, and the diameter of the mounting hole 304 is 2 - 4 mm larger than the rod diameter of the adjusting screw 5, reducing the requirement for the rotational alignment accuracy of the rotating flow tube 1 together with the magnet mounting seat. The cap of the adjusting screw 5 is also preferably flat-shaped, and it forms a planar contact connection with the gasket 6 to strengthen the structural firmness.

[0061] For each end of the sleeve 3 described above, an outer ring block 2 and an inner ring block 7 are installed and fixed to the flow tube 1 by welding. Specifically, it can be the following structure. As Figure 4 , the inside of the sleeve 3 has a long cylindrical main cavity 307 and two identical short cylindrical enlarged cavities 308. The two enlarged cavities 308 communicate with both ends of the main cavity 307. Each enlarged cavity 308 is coaxial with the main cavity 307, and the diameter of the enlarged cavity 308 is larger than that of the main cavity 307, so that a stepped annular surface 301 is formed at the connection of each end of the main cavity 307 and the enlarged cavity 308. As Figure 7 , the outer periphery of the outer ring block 2 is a cylindrical surface, and the inner peripheral surface of the outer ring block 2 is frustum-shaped. First, an outer ring block 2 is installed in each enlarged cavity 308. The smaller end of the inner opening of the outer ring block 2 faces inward, and the larger end of the inner opening faces outward. The inner end surface of the outer ring block 2 fits the stepped annular surface 301, and the outer peripheral surface of the outer ring block 2 fits the inner peripheral surface of the enlarged cavity 308. The above-mentioned inward means towards the inside of the sleeve 3, and outward means towards the outside of the sleeve 3. An inner ring block 7 is installed in each outer ring block 2. Among them, the outer peripheral surface of the inner ring block 7 is frustum-shaped, with the smaller end facing inward and the larger end facing outward. The outer peripheral surface of the inner ring block 7 fits the inner peripheral surface of the outer ring block 2. The inner peripheral surface of the inner ring block 7 is cylindrical and fits the outer wall of the flow tube 1. As Figure 7, the outer peripheral surface inclination angle α of the inner ring block 7 is 10° to 15°, and this inclination angle is the included angle between the intersection line of the plane passing through the central axis of the inner ring block 7 and the outer peripheral surface of the inner ring block 7 and the central axis. It should be noted that Figure 1 The inner peripheral surface of the outer ring block 2 of Figure 1 is a frustum shape shown schematically, Figure 7 which does not affect the Figure 1 shape expression; Figure 1 The outer peripheral surface of the inner ring block 7 of Figure 7 is a frustum shape shown schematically, Figure 1 which does not affect the Figure 7 shape expression.

[0062] The installation and adjustment method of the flowmeter structure for reducing the calibration workload of the straight tube densitometer as described above includes the following steps S1 to S10, and this installation and adjustment method includes an assembly step and a debugging step.

[0063] S1, sleeving the magnet fixing seat 4 outside the flow tube 1 and welding it in place.

[0064] S2, inserting the mutually fixed flow tube 1 and magnet fixing seat 4 into the sleeve 3. Specifically, the magnet fixing seat 4 is located at the middle pipe section of the sleeve 3, and both ends of the flow tube 1 extend outside the sleeve 3.

[0065] S3, respectively stuffing the outer ring blocks 2 at both ends of the sleeve 3, and then stuffing the inner ring blocks 7 into each outer ring block 2.

[0066] S4, applying an inward thrust F to each inner ring block 7. This thrust is generally 50 N, so that the inner ring block 7 pushes against the outer ring block 2, causing the inner end face of the outer ring block 2 to abut against the stepped ring surface 301, the outer wall surface of the outer ring block 2 to fit tightly with the inner wall surface of the sleeve 3, and the inner ring block 7 and the outer ring block 2 to fit tightly.

[0067] S5, rotating the flow tube 1 so that the internal thread hole 403 aligns with one mounting hole 304, and at the same time making the two internal magnet fixing holes 402 align with the two middle magnet fixing holes 306.

[0068] S6, as Figure 7 , on the basis of maintaining the inward thrust F applied to each inner ring block 7, welding and fixing the first contact gap 201 between the outer ring block 2 and the sleeve 3 and the second contact gap 701 between the inner ring block 7 and the flow tube 1, and then releasing the inward thrust F applied to the inner ring block 7. Then, the outer ring block 2, the inner ring block 7, the sleeve 3, and the flow tube 1 are reliably connected by the pre-tightening force.

[0069] Pass the magnet of the sensor through the middle magnet fixing hole 306 and the inner magnet fixing hole 402 and abut against the flow tube 1, fix the magnet, and turn on the power of the sensor.

[0070] S7, adaptably place the gasket 6 on an installation surface 302 where the internal thread hole 403 has been aligned. After placement, ensure that the adjustment hole 602 in the center of the gasket 6 is aligned with the installation hole 304 in the center of the installation surface 302, and rotate the gasket 6 so that the four external thread holes 601 are aligned with the four middle thread holes 303.

[0071] S8, insert the adjustment screw 5 through the adjustment hole 602, the installation hole 304 and screw it into the internal thread hole 403. Adjust the fundamental frequency of the flow tube 1 by controlling the depth of the adjustment screw 5 in the internal thread hole 403. At the same time, during the screwing process, the fundamental frequency of the flow tube 1 is detected in real time so that the fundamental frequency of the flow tube 1 reaches a set value, for example, 1020 Hz, to obtain a flowmeter structure.

[0072] S9, calibrate the measurement performance of the flowmeter structure obtained in S8 under various media, obtain the correction coefficients for various media, and record them for backup.

[0073] S10, when assembling and adjusting the flowmeter structures of the same batch, repeat steps S1 - S8 to obtain several flowmeter structures with equal fundamental frequencies. For each obtained flowmeter structure, input the correction coefficients for various media obtained in step S9 into each flowmeter structure, and repeat to complete the batch assembly and adjustment of the flowmeter structures of the same batch.

[0074] In some preferred assembly and adjustment methods, for step S8 above: after the fundamental frequency of the flow tube 1 reaches the set value, continue to tighten the adjustment screw 5 by three turns to apply a pre-tightening force to enhance the reliability of the connection. This action basically does not cause a change in the fundamental frequency; four connecting screws can also be screwed into the four external thread holes 601 to align with the four middle thread holes 303 to reinforce the connection structure between the gasket 6 and the sleeve 3. Screwing in the four connecting screws basically does not affect the fundamental frequency of the flow tube 1. The above preferred actions are equally applied to each flow tube 1 structure, with the same influence, and the fundamental frequencies of the obtained flowmeters are equal.

[0075] In the past, when batch-assembling flowmeter structures, although the same parts were used for each flowmeter structure, due to the slight differences in the parts and the differences in the assembly process, there were still some differences in the fundamental frequencies of the assembled flow tubes 1. Therefore, it was necessary to calibrate the correction coefficients of each flowmeter under each medium, resulting in a large workload.

[0076] For the structure of a straight-tube densitometer, the natural frequency (fundamental frequency) is a direct manifestation of the dynamic properties of the structure itself. Therefore, if the fundamental frequencies of straight-tube densitometers of the same model are the same, they can be considered equivalent in terms of dynamic performance. Thus, when the medium is flowing, the dynamic responses shown are consistent. In this application, a magnetic steel fixing seat 4 is fixed outside the flow tube 1, and a sleeve 3 is put on outside the flow tube 1 and the magnetic steel fixing seat 4. Both ends of the sleeve 3 are welded and fixed with an outer ring block 2 and an inner ring block 7. A gasket 6 is pasted outside the sleeve 3, and an adjusting screw 5 passes through the gasket 6 and the sleeve 3 and is screwed into the magnetic steel fixing seat 4. By adjusting the depth of the adjusting screw 5 screwed into the magnetic steel fixing seat 4, the fundamental frequencies of each flowmeter structure in the same batch can be adjusted to be equal. After this design, only the measurement performance of one straight-tube densitometer structure in various media needs to be calibrated to obtain the correction coefficients for various media, and then the correction coefficients for various media are input into other assembled flowmeters, thus completing the assembly and performance debugging of the flowmeters in the same batch, without the need to calibrate each flowmeter for multiple media. This design significantly reduces the calibration workload of the straight-tube densitometer and lowers the cost.

[0077] The above are only some embodiments of this application. The protection scope of this application is not limited to the above embodiments. For those of ordinary skill in the art of this technology, several improvements and refinements made without departing from the creative design of this application should also fall within the protection scope of this application.

Claims

1. A flow meter structure for reducing the calibration workload of a straight tube density meter, characterized in that: It comprises a flow tube (1), a magnetic steel fixing seat (4), a sleeve (3), an adjusting screw (5) and a gasket (6); The magnetic steel fixing seat (4) is fixed around the outside of the flow tube (1); the magnetic steel fixing seat (4) has a radial internal threaded hole (403); the sleeve (3) is sleeved on the magnetic steel fixing seat (4) and a section of the flow tube (1); the two ends of the sleeve (3) are fixed to the outer wall of the flow tube (1); The outer wall of the sleeve (3) has a mounting surface (302), and the sleeve (3) also has a mounting hole (304) penetrating from the mounting surface (302) to the inner wall of the sleeve (3); the gasket (6) has an adjustment hole (602); the gasket (6) fits the mounting surface (302) so that the adjustment hole (602) and the mounting hole (304) are concentrically aligned; the adjustment screw (5) passes through the adjustment hole (602) and the mounting hole (304), and is inserted into the internal threaded hole (403) and threadedly connected with the internal threaded hole (403) to fit each other, so that the gasket (6), the sleeve (3) and the flow tube (1) are fixed to each other.

2. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 1, characterized in that: The adjustment hole (602) and the mounting hole (304) are both round holes; the diameter of the adjustment hole (602) is 2 to 4 mm larger than the rod diameter of the adjustment screw (5); and the diameter of the mounting hole (304) is 2 to 4 mm larger than the rod diameter of the adjustment screw (5).

3. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 1, characterized in that: The mounting surface (302) is a plane; the side of the adjusting screw (5) in contact with the gasket (6) is a plane; the adjusting screw (5) and the gasket (6) are in plane contact; the gasket (6) and the mounting surface (302) are in plane contact.

4. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 1, characterized in that: The gasket (6) also has a plurality of external threaded holes (601); the sleeve (3) also has a plurality of middle threaded holes (303) penetrating from the mounting surface (302) to the inner wall of the sleeve (3); the flow meter structure also includes a plurality of connecting screws; each of the connecting screws passes through one of the external threaded holes (601) and one of the middle threaded holes (303) to fix the gasket (6) to the sleeve (3).

5. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 1, characterized in that: The outer wall surface of the magnetic steel fixing seat (4) has two symmetrical and parallel inner fixing planes (401), and an inner magnetic steel fixing hole (402) penetrating from the inner fixing plane (401) to the inner wall surface of the magnetic steel fixing seat (4); the sleeve (3) has two symmetrical middle magnetic steel fixing holes (306); when the inner threaded hole (403) is aligned with the mounting hole (304), the two inner magnetic steel fixing holes (402) are aligned with the two middle magnetic steel fixing holes (306).

6. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 5, characterized in that: The outer wall of the sleeve (3) has two symmetrical and parallel mounting surfaces (302), each mounting surface (302) being provided with the mounting hole (304); the outer wall of the sleeve (3) also has two middle fixing planes (305), each middle fixing plane (305) being provided with a middle magnetic steel fixing hole (306); the two mounting surfaces (302) are perpendicular to the two middle fixing planes (305).

7. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 1, characterized in that: The sleeve (3) has a cylindrical main cavity (307) and two cylindrical expansion cavities (308) inside; the two expansion cavities (308) are connected to the two ends of the main cavity (307); the diameter of the expansion cavity (308) is larger than that of the main cavity (307), so that a step annular surface (301) is formed at the connection between each end of the main cavity (307) and the expansion cavity (308); The flow meter structure also includes two outer ring blocks (2) and two inner ring blocks (7); one outer ring block (2) is installed in each of the expansion chambers (308), and one inner ring block (7) is installed in each of the outer ring blocks (2); the outer circumferential surface of the outer ring block (2) is fitted and fixed to the inner circumferential surface of the expansion chamber (308), and the inner end surface of the outer ring block (2) is fitted to the step ring surface (301); the inner circumferential surface of each of the outer ring blocks (2) is in the shape of a truncated cone, with the small end facing inward and the large end facing outward; the outer circumferential surface of the inner ring block (7) is in the shape of a truncated cone, with the small end facing inward and the large end facing outward; the outer circumferential surface of the inner ring block (7) is fitted to the inner circumferential surface of the outer ring block (2); the inner circumferential surface of the inner ring block (7) is in the shape of a cylinder, and is fitted and fixed to the flow tube (1).

8. The flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 7, characterized in that: The outer peripheral surface inclination angle of the inner ring block (7) is 10° to 15°.

9. A method for assembling and adjusting a flow meter structure for reducing the calibration workload of a straight tube density meter as claimed in claim 7 or 8, characterized in that: The adjustment method comprises: S1, sleeve the magnetic steel fixing seat (4) outside the flow tube (1) and fix them together; S2, inserting the flow tube (1) and the magnetic steel fixing seat (4) fixed to each other into the sleeve (3); S3, installing the outer ring blocks (2) at both ends of the sleeve (3), and then installing the inner ring block (7) in each of the outer ring blocks (2); S4, applying an inward thrust to each of the inner ring blocks (7), so that the inner ring block (7) pushes the outer ring block (2), so that the inner end surface of the outer ring block (2) abuts against the step annular surface (301), and the outer wall surface of the outer ring block (2) and the inner wall surface of the sleeve (3) are in close contact; S5, rotating the flow tube (1) so that the internal threaded hole (403) is aligned with the mounting hole (304); S6, while maintaining the inward thrust applied to each of the inner ring blocks (7), welding and fixing the contact gap between the outer ring block (2) and the sleeve (3) and the contact gap between the inner ring block (7) and the flow tube (1), and then releasing the inward thrust applied to the inner ring block (7); S7, placing the gasket (6) on the mounting surface (302) so that the adjustment hole (602) is aligned with the mounting hole (304); S8, inserting the adjusting screw (5) into the adjusting hole (602), the mounting hole (304) and screwing it into the internal threaded hole (403), adjusting the fundamental frequency of the flow tube (1) by rotating the adjusting screw (5), and detecting the fundamental frequency of the flow tube (1) during the screwing process, so that the fundamental frequency of the flow tube (1) reaches a set value, thereby obtaining a flow meter structure; S9, calibrating the measurement performance of the flow meter structure obtained in S8 under various media to obtain correction coefficients for various media; S10, when assembling and adjusting the flow meter structures of the same batch, repeat steps S1 to S8 to obtain a plurality of flow meter structures with the same fundamental frequency; for each flow meter structure obtained, input the medium correction coefficients obtained in step S9 into each flow meter structure, and repeat the batch adjustment of the flow meter structures of the same batch.

10. The method for assembling and adjusting a flow meter structure for reducing the calibration workload of a straight tube density meter according to claim 9, characterized in that: In step S8, when the fundamental frequency of the flow tube (1) reaches the set value, the adjusting screw (5) is further tightened three turns.

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