Flowmeter structure and installation method to reduce the calibration workload of straight tube density meter

Abstract

The present application relates to the technical field of calibration of straight tube density meters, and specifically discloses a flow meter structure and an adjustment method for reducing the calibration workload of straight tube density meters. The flow meter structure includes a flow tube, a magnetic steel fixing seat, a sleeve, an adjusting screw and a gasket. The magnetic steel fixing seat is fixed around the outside of the flow tube. The magnetic steel fixing seat has an internal threaded hole. The sleeve is sleeved on the outside of the magnetic steel 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 fits the mounting surface. The adjusting screw passes through the gasket and the mounting hole, and is inserted into the internal threaded hole. The base frequency of the flow tube is adjusted by changing the depth of the adjusting screw screwed into the magnetic steel fixing seat. When producing the same batch of straight tube density meters, each flow meter is adjusted to the same base frequency, and only one flow meter is measured for multiple fluid media to obtain multiple correction coefficients. The obtained multiple correction coefficients are input into other flow meters, which significantly reduces 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 installation and 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 flow meter structure for reducing the calibration workload of a straight tube density meter comprises a flow tube, a magnetic steel fixing seat, a sleeve, an adjusting screw and a gasket.

[0009] The magnetic steel fixing seat is fixed around the outside of the flow tube. The magnetic steel fixing seat has a radial internal threaded hole. The sleeve is sleeved outside the magnetic steel 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 adjustment hole. The gasket fits the mounting surface so that the adjustment hole and the mounting hole are concentrically aligned. The adjustment screw passes through the adjustment hole and the mounting hole, and is inserted into the internal threaded hole and the internal threaded hole for adaptive threaded connection, so that the gasket, the sleeve and the flow tube are fixed to each other.

[0011] By adopting the above technical scheme, the adjusting screw is connected in series with the gasket, the sleeve and the magnetic steel fixing seat, and the magnetic steel fixing seat is fixed to the flow tube, so that the fundamental frequency of the flow tube can be adjusted by changing the depth of the adjusting screw screwed into the magnetic steel fixing seat. When producing the same batch of straight tube density meters, the same specification of components are used. By appropriately adjusting the depth of the adjusting screw screwed into the magnetic steel fixing seat, each flow meter can be adjusted to the same fundamental frequency. For flow meters with the same fundamental frequency, multiple correction coefficients can be obtained by measuring one flow meter for multiple fluid media. The obtained multiple correction coefficients can be input into other flow meters for use without the need to test other flow meters for multiple fluid media to obtain multiple correction coefficients. This significantly reduces the calibration workload, which can not only improve the consistency of batches of straight tube density meters, but also improve the reliability of straight tube density meters.

[0012] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight tube density meter is that the adjustment hole and the mounting hole are both round holes. The diameter of the adjustment hole is 2 to 4 mm larger than the rod diameter of the adjustment screw. The diameter of the mounting hole is 2 to 4 mm larger than the rod diameter of the adjustment screw.

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

[0014] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight tube density meter is that the mounting surface is a plane, the side where the adjusting screw and the gasket contact is a plane, the adjusting screw and the gasket are in plane contact, and the gasket and the mounting surface are in plane contact.

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

[0016] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight tube density meter is that the gasket also has a plurality of external threaded holes. The sleeve also has a plurality of middle threaded holes penetrating from the mounting surface to the inner wall of the sleeve. The flowmeter structure also 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, the setting strengthens the connection stability between the gasket and the sleeve.

[0018] A preferred solution for the flowmeter structure that reduces the calibration workload of the straight tube density meter is that the outer wall surface of the magnetic steel fixing seat has two symmetrical and parallel internal fixing planes, and an internal magnetic steel fixing hole penetrating from the internal fixing planes to the inner wall surface of the magnetic steel fixing seat; the sleeve has two symmetrical middle magnetic steel fixing holes; when the internal threaded hole is aligned with the mounting hole, the two internal magnetic steel fixing holes are aligned with the two middle magnetic steel fixing holes.

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

[0020] A preferred solution for the flowmeter structure that reduces the calibration workload of the straight tube density meter is that the outer wall of the sleeve has two symmetrical and parallel mounting surfaces, and the mounting hole is arranged in each mounting surface; the outer wall of the sleeve also has two middle fixing planes, and a middle magnetic steel fixing hole is arranged in each middle fixing plane; 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 magnetic steel fixing seat and the sleeve, which facilitates the rotational alignment of the magnetic steel fixing seat in the sleeve.

[0022] A preferred solution of the flowmeter structure for reducing the calibration workload of the straight tube density meter is that the sleeve has a cylindrical main cavity and two cylindrical expansion cavities inside. The two expansion cavities are connected to the two ends of the main cavity, and the diameter of the expansion cavity is larger than that of the main cavity, so that a step annular surface is formed at the connection between each end of the main cavity and the expansion cavity.

[0023] The flow meter structure also includes two outer ring blocks and two inner ring blocks. One outer ring block is installed in each of the expansion chambers, and one inner ring block is installed in each of the outer ring blocks. The outer circumferential surface of the outer ring block fits and fixes the inner circumferential surface of the expansion chamber, and the inner end surface of the outer ring block fits and fixes the step ring surface. The inner circumferential surface of each outer ring block is truncated cone-shaped, with the small end facing inward and the large end facing outward. The outer circumferential surface of the inner ring block is truncated cone-shaped, with the small end facing inward and the large end facing outward. The outer circumferential surface of the inner ring block fits and fixes the inner circumferential surface of the outer ring block. The inner circumferential surface of the inner ring block is cylindrical, fitting and fixing the flow tube.

[0024] By adopting the above technical solution, the mechanism facilitates the rotation of the flow tube without losing position during rotation, facilitates the alignment of the internal threaded hole of the magnetic steel fixing seat and the mounting hole of the sleeve, and can be welded and fixed after alignment.

[0025] A preferred solution for the flowmeter structure that reduces the calibration workload of the straight tube density meter 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 ring block is squeezed by the outer peripheral surface of the inner ring block at the inclined angle to achieve positioning and pre-tightening. This method increases the connection boundary stiffness and better ensures the consistency of the fundamental frequency of the mass-produced flow meter structure.

[0027] In a second aspect, the present application proposes a method for assembling and adjusting a flow meter structure to reduce the calibration workload of a straight tube density meter, and adopts the following technical solution.

[0028] A flow meter structure adjustment method for reducing the calibration workload of a straight tube density meter as described above, the adjustment method comprising: S1, the magnetic steel fixing seat is sleeved outside the flow tube and fixed to each other.

[0029] S2, inserting the flow tube and the magnetic steel fixing seat fixed to each other into the sleeve.

[0030] S3, installing the outer ring blocks at both ends of the sleeve respectively, and then installing the inner ring block in each of the outer ring blocks.

[0031] S4, applying an inward thrust to each of the inner ring blocks, so that the inner ring block pushes the outer ring block, so that the inner end surface of the outer ring block abuts against the step annular surface, and the outer wall surface of the outer ring block and the inner wall surface of the sleeve are tightly fitted.

[0032] S5, rotating the flow tube so that the internal threaded hole is aligned with the mounting hole.

[0033] S6, on the basis of maintaining the inward thrust applied to each of the inner ring blocks, the contact gap between the outer ring block and the sleeve, and the contact gap between the inner ring block and the flow tube are welded and fixed, and then the inward thrust applied to the inner ring block is released.

[0034] S7, placing the gasket on the mounting surface so that the adjustment hole is aligned with the mounting hole.

[0035] S8, insert the adjusting screw into the adjusting hole, the mounting hole and screw it into the internal threaded hole, adjust the fundamental frequency of the flow tube by rotating the adjusting screw, and 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, thereby obtaining the flow meter structure.

[0036] S9, calibrating the measurement performance of the flow meter structure obtained in S8 under various media to obtain correction coefficients for various media.

[0037] S10, when adjusting the flowmeter structures of the same batch, repeat steps S1 to S8 to obtain a plurality of flowmeter structures with the same fundamental frequency. For each obtained flowmeter structure, input the medium correction coefficients obtained in step S9 into each flowmeter structure, and repeat the batch adjustment of the flowmeter structures of the same batch.

[0038] By adopting the above technical solution, the flow meters manufactured in batches have fundamental frequency consistency and the workload of flow meter calibration is reduced.

[0039] A preferred solution of the above flowmeter structure adjustment method for reducing the straight tube density meter calibration workload is that in step S8, when the fundamental frequency of the flow tube reaches the set value, the adjusting screw is further tightened for three turns.

[0040] By adopting the above technical solution, the pre-tightening force is applied in this way to enhance the reliability of the connection.

[0041] In summary, the flowmeter structure and installation method of the present application for reducing the calibration workload of a straight tube density meter have the following beneficial effects: by designing the adjustment screw connection form of the casing and the magnetic steel fixing seat and adjusting the depth of the adjustment screw, the fundamental frequency of the flowmeter can be fine-tuned. When manufacturing the same batch of flowmeters, the fundamental frequency of each flowmeter can be adjusted to a consistent target value. On this basis, by measuring the measurement performance of a flowmeter under multiple media, calibration is performed to obtain the correction coefficient of each medium, and the correction coefficient of each medium is input into other flowmeters manufactured in the same batch. Other flowmeters manufactured in the same batch are exempted from testing the measurement performance calibration under each medium, thereby reducing the calibration workload, reducing costs, and improving market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The cross-sectional internal structure diagram of a flow meter structure that reduces the calibration workload of a straight tube density meter.

[0043] Figure 2 Schematic diagram of the flow tube.

[0044] Figure 3 This is a structural diagram of the magnetic steel fixing seat.

[0045] Figure 4 The cross-sectional internal structure diagram of the casing.

[0046] Figure 5 This is the external structure diagram of the casing.

[0047] Figure 6 This is a structural diagram of the gasket.

[0048] Figure 7 Schematic diagram of the pre-tightening connection between the outer ring block and the inner ring block.

[0049] Figure numerals: 1, flow tube; 4, magnetic steel fixing seat; 3, sleeve; 5, adjustment screw; 6, gasket; 2, outer ring block; 7, inner ring block; 401, inner fixing plane; 402, inner magnetic steel fixing hole; 403, internal threaded hole; 302, mounting surface; 305, middle fixing plane; 304, mounting hole; 303, middle threaded hole; 306, middle magnetic steel fixing hole; 602, adjustment hole; 601, external threaded hole; 603, circular plane; 301, step annular surface; 307, main cavity; 308, expansion cavity; 201, first contact gap; 701, second contact gap. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the following embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] refer to Figure 1 A flowmeter structure for reducing the calibration workload of a straight tube density meter includes a flow tube 1, a magnetic steel fixing seat 4, a sleeve 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.

[0052] like Figure 2 , flow tube 1 is a thin round tube.

[0053] like Figure 3The magnetic steel fixing seat 4 is an annular column, which is tightly sleeved on the outside of the flow tube 1 and can be welded and fixed to each other. There are two symmetrical internal fixed planes 401 on both sides of the outer periphery of the magnetic steel fixing seat 4, and the two internal fixed planes 401 are parallel to each other. The magnetic steel fixing seat 4 also has two radial internal magnetic steel fixing holes 402 and a radial internal threaded hole 403. Each internal magnetic steel fixing hole 402 penetrates from an internal fixed plane 401 to the inner annular surface of the magnetic steel fixing seat 4, which is convenient for installing the magnet and abutting the flow tube 1 to test the fundamental frequency of the flow tube 1. The internal threaded hole 403 also penetrates from the outer periphery of the magnetic steel fixing seat 4 to the inner annular surface of the magnetic steel fixing seat 4, which is perpendicular to the connecting line of the two internal magnetic steel fixing holes 402.

[0054] The sleeve 3 is sleeved outside the magnetic steel fixing seat 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 the sleeve 3 is fixed to the flow tube 1 by welding, but the two ends of the flow tube 1 extend outside the inner ring block 7. Before welding, the internal threaded hole 403 and the sleeve 3 need to be aligned.

[0055] like Figure 4 The outer wall of the sleeve 3 has two symmetrically parallel mounting surfaces 302 and two symmetrically parallel middle fixing planes 305. The mounting surface 302 is also a plane. The mounting surface 302 and the fixing surface are perpendicular to each other and are both sunken in the outer circular wall of the sleeve 3. Each mounting surface 302 is provided with a mounting hole 304, which penetrates the tube wall of the sleeve 3, and only one mounting hole 304 is used for alignment with the internal threaded hole 403.

[0056] like Figure 5 , four middle threaded holes 303 are also provided on the mounting surface 302, which are distributed around the mounting hole 304. A middle magnetic steel fixing hole 306 is provided on each middle fixing plane 305, which is opposite to the two inner magnetic steel fixing holes 402, and is used for the magnetic steel to pass through and fix, so as to use the magnetic steel to test the fundamental frequency of the flow tube 1. The magnetic steel is not shown in the drawings, and the magnetic steel in the sensor for testing the fundamental frequency of the flow tube 1 passes through the middle magnetic steel fixing hole 306 and the inner magnetic steel fixing hole 402 and abuts against the flow tube 1, so that the sensor can measure the fundamental frequency of the flow tube 1.

[0057] like Figure 6 The gasket 6 is an oblate cylindrical shape, with a circular plane 603 on the end face, and five holes, namely, a central adjustment hole 602 and four external threaded holes 601. The four external threaded holes 601 are located on the circumference of the adjustment hole 602. The adjustment hole 602 is aligned with the mounting hole 304 and the internal threaded hole 403. The four external threaded holes 601 and the four internal threaded holes 303 are aligned one by one, and connected with four connecting screws (not shown in the drawings), so as to fix the gasket 6 to the sleeve 3. It should be noted that: Figure 6The four external threaded holes 601 are schematically arranged in 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 positions of the four external threaded holes 601 and the four threaded holes 303 can be randomly arranged as long as they can be aligned one by one, but preferably as follows Figure 5 Circumferentially equidistantly arranged.

[0058] The mounting surface 302 is a plane, but its outer circumference can be circular and match the outer circumference of the gasket 6, so that the gasket 6 fits the mounting surface 302, and the gasket 6 can be restricted in the mounting surface 302 by the sleeve 3. No matter how the gasket 6 is rotated, the adjustment hole 602 in the center of the gasket 6 is precisely aligned with the mounting hole 304 on the sleeve 3.

[0059] The adjusting screw 5 is used to pass through the adjusting hole 602 and the mounting hole 304, and is inserted into the internal threaded hole 403 and the internal threaded hole 403 for threaded connection. The adjusting hole 602 and the mounting hole 304 can be round holes. In order to facilitate the alignment of the internal threaded hole 403, the adjusting hole 602 and the mounting hole 304, the present solution sets the aperture of the adjusting hole 602 to be 2 to 4 mm larger than the rod diameter of the adjusting screw 5, and the aperture of the mounting hole 304 to be 2 to 4 mm larger than the rod diameter of the adjusting screw 5, thereby reducing the rotational alignment accuracy requirements of the rotating flow tube 1 together with the magnetic steel mounting seat. The nail cap of the adjusting screw 5 is also preferably in the shape of a flat plate, which forms a planar contact connection with the gasket 6 to enhance the structural firmness.

[0060] An outer ring block 2 and an inner ring block 7 are installed at each end of the sleeve 3 described above, and fixed to the flow tube 1 by welding. Specifically, the structure may be as follows. Figure 4 The sleeve 3 has a main cavity 307 in the shape of a long cylinder and two expansion cavities 308 in the shape of short cylinders. The two expansion cavities 308 are connected to the two ends of the main cavity 307. Each expansion cavity 308 is coaxial with 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. Figure 7 , the outer circumference of the outer ring block 2 is a cylindrical surface, and the inner circumference of the outer ring block 2 is a truncated cone. An outer ring block 2 is first installed in each expansion cavity 308, with the end of the outer ring block 2 with a small inner opening facing inward, and the end with a large inner opening facing outward. The inner end face of the outer ring block 2 fits the step ring surface 301, and the outer circumference of the outer ring block 2 fits the inner circumference of the expansion cavity 308. The above-mentioned inward facing means facing the inside of the casing 3, and outward facing means facing the outside of the casing 3. An inner ring block 7 is installed in each outer ring block 2. Among them, the outer circumference of the inner ring block 7 is a truncated cone, with the small end facing inward and the large end facing outward. The outer circumference of the inner ring block 7 fits the inner circumference of the outer ring block 2. The inner circumference of the inner ring block 7 is cylindrical and fits the outer wall of the flow tube 1. As Figure 7The outer peripheral surface inclination angle α of the inner ring block 7 is 10°~15°, which is the 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 outer ring block 2 is not shown, and the inner circumference is a truncated cone. Figure 1 This is a schematic structure and does not affect Figure 7 Shape expression; Figure 1 The outer peripheral surface of the inner ring block 7 is not shown as a truncated cone. Figure 1 This is a schematic structure and does not affect Figure 7 shape expression. Figure 1 It can be an implementation method. Figure 7 This is another more preferred embodiment.

[0061] The above flowmeter structure adjustment method for reducing the straight tube density meter calibration workload includes the following steps S1 to S10, and the adjustment method includes an assembly step and a debugging step.

[0062] S1, put the magnetic steel fixing seat 4 outside the flow tube 1 and weld it to fix it.

[0063] S2, inserting the mutually fixed flow tube 1 and magnetic steel fixing seat 4 into the casing 3, specifically, the magnetic steel fixing seat 4 is located at the middle pipe section in the casing 3, and the two ends of the flow tube 1 extend out of the casing 3.

[0064] S3, insert the outer ring blocks 2 into the two ends of the sleeve 3 respectively, and then insert the inner ring block 7 into each outer ring block 2.

[0065] S4, apply an inward thrust F to each inner ring block 7, which is generally 50N, so that the inner ring block 7 pushes the outer ring block 2, so that the inner end face of the outer ring block 2 abuts against the step ring surface 301, the outer wall surface of the outer ring block 2 and the inner wall surface of the sleeve 3 fit tightly, and the inner ring block 7 and the outer ring block 2 fit tightly.

[0066] S5, rotating the flow tube 1 so that the internal threaded hole 403 is aligned with a mounting hole 304, and simultaneously the two inner magnetic steel fixing holes 402 are aligned with the two middle magnetic steel fixing holes 306.

[0067] S6, such as Figure 7 On the basis of maintaining the inward thrust F applied to each inner ring block 7, 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 are welded and fixed, and then the inward thrust F applied to the inner ring block 7 is released. 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.

[0068] The magnet of the sensor is passed through the middle magnet fixing hole 306 and the inner magnet fixing hole 402 and abuts against the flow tube 1, the magnet is fixed, and the power of the sensor is turned on.

[0069] S7, fit the gasket 6 on a mounting surface 302 where the internal threaded hole 403 has been aligned, so that the adjustment hole 602 in the center of the gasket 6 is aligned with the mounting hole 304 in the center of the mounting surface 302, and rotate the gasket 6 so that the four external threaded holes 601 are aligned with the four middle threaded holes 303.

[0070] S8, insert the adjusting screw 5 into the adjusting hole 602, the mounting hole 304 and screw it into the internal threaded hole 403, and adjust the fundamental frequency of the flow tube 1 by controlling the depth of the adjusting screw 5 in the internal threaded hole 403. At the same time, the fundamental frequency of the flow tube 1 is detected in real time during the screwing-in process, so that the fundamental frequency of the flow tube 1 reaches the set value, for example, 1020 Hz, to obtain a flow meter structure.

[0071] S9, calibrating the measurement performance of the flow meter structure obtained in S8 under various media, obtaining the correction coefficient of each medium, and recording it for future use.

[0072] S10, when adjusting the flowmeter structures of the same batch, repeat steps S1 to S8 to obtain a plurality of flowmeter structures with the same fundamental frequency. For each flowmeter structure obtained, input the medium correction coefficients obtained in step S9 into each flowmeter structure, and repeat the batch adjustment of the flowmeter structures of the same batch.

[0073] In some preferred installation and adjustment methods, for the above step S8: when the fundamental frequency of the flow tube 1 reaches the set value, the adjusting screw 5 is further tightened for three turns to apply pre-tightening force to enhance the reliability of the connection, and this action basically does not cause the change of the fundamental frequency; the four connecting screws can also be screwed into the four external threaded holes 601 to align with the four middle threaded holes 303 to reinforce the connection structure of the gasket 6 and the sleeve 3, and screwing in the four connecting screws basically does not affect the fundamental frequency of the flow tube 1. The above preferred actions are applied equally to each flow tube 1 structure, and the influence is the same, and the fundamental frequency of the obtained flow meter is equal.

[0074] In the past, when flow meter structures were assembled in batches, although each flow meter structure used the same parts, due to slight differences in the parts and differences in the assembly process, there were still some differences in the fundamental frequency of the assembled flow tube 1. Therefore, it was necessary to calibrate the correction coefficient of each flow meter under each medium, which was a lot of work.

[0075] For the straight tube density meter structure, the natural frequency (fundamental frequency) is a direct reflection of the structure's own dynamic properties. Therefore, if the fundamental frequencies of straight tube density meters of the same style are the same, they can be equivalent to the same dynamic performance. Therefore, when the medium flows, the dynamic response reflected is consistent. The present application fixes a magnetic steel fixing seat 4 on the outside of the flow tube 1, and sleeves 3 are sleeved on the outside of 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 attached to the outside of the sleeve 3, and an adjusting screw 5 is passed through the gasket 6 and the sleeve 3 and 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, each flow meter structure of the same batch can be adjusted to have the same fundamental frequency. After this design, it is only necessary to measure the measurement performance of a straight tube density meter structure under various media for calibration, and obtain the correction coefficient of each medium. After that, the correction coefficient of each medium is input into other assembled flow meters, and the assembly and performance debugging of the same batch of flow meters are completed without the need to calibrate each flow meter with multiple media. This design significantly reduces the calibration workload of the straight tube density meter and reduces the cost.

[0076] The above are only some embodiments of the present application, and the protection scope of the present application is not limited to the above embodiments. For ordinary technicians in this technical field, some improvements and modifications without departing from the creative design of the present application should also fall within the protection scope of the present 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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