Coriolis flowmeter

Abstract

To provide technology with which it is possible to suppress overlapping of weld sections of a manifold and each of a pair of sensor tubes.SOLUTION: A vibration-type measurement device 1 pertaining to one embodiment comprises: a manifold 50; sensor tubes 52, 53 joined to the manifold 50 by welding, and in which fluid to be measured flows through; a vibration exciter 54 for causing the sensor tubes 52, 53 to vibrate in a direction to come closer and a direction to separate; vibration pickups 55, 56 which are disposed upstream and downstream of the location in the sensor tubes 52, 53 that is vibrated by the vibration exciter 54, and which output a signal corresponding to the relative displacements of the sensor tubes 52, 53. The manifold 50 includes a hole 504 into which the sensor tube 52 is inserted, and a hole 505 into which the sensor tube 53 is inserted, and the surface 508a where the hole 504 is provided and the surface 508b where the hole 505 is provided are separated by a groove 509 between the hole 504 and the hole 505.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to Coriolis flow meters. [Background technology]

[0002] Conventionally, a Coriolis flowmeter is known in which a pair of sensor tubes are vibrated relative to one another, the relative displacement between the pair of sensor tubes is detected by a vibration sensor, and the mass flow rate of a fluid flowing through the pair of sensor tubes is measured from the relative displacement (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-186081 A Summary of the Invention [Problem to be solved by the invention]

[0004] In some cases, the pair of sensor tubes are inserted into holes in a manifold where an inlet and outlet for fluid are provided, and connected to the manifold by welding. In such cases, the welded parts of the pair of sensor tubes may overlap. Therefore, for example, when the mass flow rate of a high-pressure gas is to be measured, the overlapping part of the welded parts may become the starting point of a crack.

[0005] In view of the above problem, an object of the present invention is to provide a technique capable of suppressing overlapping of the welded portions between the manifold and each of a pair of sensor tubes. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, a manifold provided with at least one of an inlet and an outlet for a fluid to be measured; a pair of sensor tubes joined to the manifold by welding and through which the fluid to be measured flows; an excitation unit that vibrates the pair of sensor tubes in directions toward and away from each other; a vibration sensor provided on each of the pair of sensor tubes on the upstream side and the downstream side of a portion where the vibration is applied by the excitation unit, the vibration sensor outputting a signal corresponding to a relative displacement of the pair of sensor tubes; the manifold has a first hole into which one of the pair of sensor tubes is inserted and a second hole into which the other is inserted, and a first surface portion on which the first hole is provided and a second surface portion on which the second hole is provided are spaced apart between the first hole and the second hole. A Coriolis flow meter is provided. Effect of the Invention

[0007] According to the above-described embodiment, it is possible to prevent overlapping of the welded portions between the manifold and each of the pair of sensor tubes. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of a vibration type measuring device. [Diagram 2] FIG. 1 is a diagram illustrating an example of a vibration type measuring device. [Diagram 3] FIG. 2 is a perspective view illustrating an example of a manifold. [Figure 4] FIG. 2 is a top view illustrating an example of a manifold. [Diagram 5] FIG. 2 is a cross-sectional view showing an example of a manifold. [Figure 6] 13A and 13B are diagrams showing experimental results of welding a manifold and a sensor tube according to a comparative example. [Figure 7] 13A and 13B are diagrams showing experimental results of welding a manifold and a sensor tube according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings.

[0010] [Configuration of vibration measuring device] A vibration type measuring device 1 according to this embodiment will be described with reference to FIGS.

[0011] Fig. 1 is a diagram showing an example of a vibration-type measuring device 1. Specifically, Fig. 1 is a front view showing the example of the vibration-type measuring device 1, and Fig. 2 is a side view showing the example of the vibration-type measuring device 1.

[0012] Hereinafter, in this embodiment, the directions shown in FIG. 1 and FIG. 2 (front-back, left-right, top-bottom directions) may be used for convenience in the description.

[0013] The vibration type measurement device 1 is used as a vibration type densitometer that measures the density of a fluid to be measured, or a Coriolis type mass flowmeter that measures the mass flow rate of the fluid to be measured by using the density of the measurement result. Since the vibration type densitometer and the Coriolis type mass flowmeter have the same configuration, this example will explain the case where the device is used as a Coriolis type mass flowmeter.

[0014] The vibration type measuring device 1 (Coriolis type mass flowmeter) is built into a gas supply device installed in a gas supply station or the like that supplies a specific gas to a fuel tank of an automobile, and measures the mass flow rate of the gas supplied from the gas supply device to the fuel tank of the automobile. The specific gas as the measured fluid is, for example, compressed natural gas (CNG) obtained by compressing city gas to a specific pressure, high-pressure hydrogen gas, etc.

[0015] As shown in FIGS. 1 and 2, the vibration type measuring device 1 includes manifolds 50 and 51, a pair of sensor tubes 52 and 53, a vibrator 54, vibration pickups 55 and 56, a temperature sensor 57, and a control circuit 60.

[0016] The manifold 50 is made of metal and is provided with an inlet 50a for the fluid to be measured. Similarly, the manifold 51 is made of metal and is provided with an outlet 51a for the fluid to be measured.

[0017] The sensor tubes 52 and 53 are made of metal and are connected to the upper surfaces of the manifolds 50 and 51 .

[0018] Sensor tube 52 has an inverted U-shape including a pipe line portion 52a extending upward from manifold 50, a pipe line portion 52b extending upward from manifold 51, and a pipe line portion 52c connected to the ends of pipe lines 52a and 52b and having a curved shape (arc shape).

[0019] Similarly, sensor tube 53 has an inverted U-shape including a pipe line portion 53a extending upward from manifold 50, a pipe line portion 53b extending upward from manifold 51, and a pipe line portion 53c connected to the ends of pipe lines 53a and 53b and having a curved shape (arc shape).

[0020] The base ends of the pipe sections 52a, 53a of the sensor tubes 52, 53 are connected to the inlet section 50a of the manifold 50, and the pipe sections 52b, 53b of the sensor tubes 52, 53 are connected to the outlet section 51a of the manifold 51. As a result, the fluid to be measured flowing in from the inlet section 50a passes through the sensor tubes 52, 53 and flows out from the outlet section 51a to the outside.

[0021] Vibrator 54 is attached between arc-shaped pipe sections 52c, 53c of sensor tubes 52, 53. It includes an excitation coil 54a attached to the tip of sensor tube 52, and a magnet 54b attached to the tip of sensor tube 53. Under the control of control circuit 60, vibrator 54 vibrates sensor tubes 52, 53 in directions toward and away from each other.

[0022] Specifically, in the vibrator 54, a positive and negative alternating voltage (AC signal) is applied to the excitation coil 54a, and the magnet 54b attracts or repels the magnetic field generated by the excitation coil 54a, thereby vibrating the pipe section 52c of the sensor tube 52 in the horizontal direction (specifically, the front-to-rear direction). On the other hand, a force of the same magnitude acts on the sensor tube 53 as a reaction force, and the sensor tube 53 vibrates in the opposite direction.

[0023] The vibration pickup 55 is provided upstream (inflow side) of the fluid to be measured from the point on the sensor tubes 52, 53 that is vibrated by the vibrator 54, and measures (detects) the relative vibration state of the sensor tubes 52, 53 on the inflow side of the fluid to be measured. The vibration pickup 55 corresponds to, for example, a displacement detector, and detects the relative displacement on the inflow side of the sensor tubes 52, 53 as a detection signal. The vibration pickup 55 includes a sensor coil 55a attached to the sensor tube 52 and a magnet 55b attached to the sensor tube 53. The detection signal detected by the vibration pickup 55 (sensor coil 55a) is input to the control circuit 60.

[0024] The sensor coil 55a and magnet 55b of the vibration pickup 55 approach and move away together with the vibration of the inflow-side sensor tubes 52 and 53. Therefore, the sensor coil 55a outputs an electromotive force generated according to the displacement amount (displacement speed) of the sensor coil 55a and magnet 55b on the inflow side of the fluid to be measured as a detection signal.

[0025] The vibration pickup 56 is provided downstream (outflow side) of the fluid to be measured from a point on the sensor tubes 52, 53 that is vibrated by the vibrator 54, and measures (detects) the vibration state of the sensor tubes 52, 53 on the outflow side of the fluid to be measured. The vibration pickup 56 corresponds to, for example, a displacement detector, and detects the relative displacement on the outflow side of the sensor tubes 52, 53. The vibration pickup 56 includes a sensor coil 56a attached to the sensor tube 52 and a magnet 56b attached to the sensor tube 53. A detection signal detected by the vibration pickup 56 (sensor coil 56a) is input to the control circuit 60.

[0026] Like the vibration pickup 55, the sensor coil 56a and magnet 56b of the vibration pickup 56 approach and move away together with the vibration of the sensor tubes 52, 53 on the outflow side of the measured fluid. Therefore, the sensor coil 56a outputs an electromotive force generated according to the displacement amount (displacement speed) of the sensor coil 56a and magnet 56b on the outflow side of the measured fluid as a detection signal.

[0027] 1, the vibrator 54, the vibration pickup 55, and the vibration pickup 56 are arranged symmetrically with respect to a vertical line that crosses the middle positions of the sensor tubes 52 and 53 when viewed from the front (front). Moreover, the vibration pickup 55 and the vibration pickup 56 are arranged symmetrically with respect to the vibrator 54.

[0028] The temperature sensor 57 measures the temperature in the inlet pipe sections 52 a , 53 a of the sensor tubes 52 , 53 or in the vicinity of the inlet section 50 a of the manifold 50 .

[0029] The temperature sensor 57 may be omitted.

[0030] The control circuit 60 controls the vibration type measuring device 1. The functions of the control circuit 60 may be realized by any hardware or any combination of hardware and software. For example, the control circuit 60 is mainly configured with a computer including a CPU (Central Processing Unit), a memory device, an auxiliary storage device, and an interface device for input / output with the outside.

[0031] For example, the control circuit 60 applies an AC signal to the vibrator 54 and performs control to cause the vibrator 54 to vibrate.

[0032] Furthermore, the control circuit 60 may measure (calculate) the density and mass flow rate of the fluid to be measured flowing through the sensor tubes 52, 53 based on the detection signals captured by the vibration pickups 55, 56.

[0033] [Manifold configuration] Next, the configuration of the manifolds 50, 51 of the vibration type measuring instrument 1 according to this embodiment will be described with reference to FIGS.

[0034] Fig. 3 is a perspective view showing an example of the manifold 50. Fig. 4 is a top view showing an example of the manifold 50. Fig. 5 is a cross-sectional view showing an example of the manifold 50. Specifically, Fig. 5 is a cross-sectional view taken along line AA in Fig. 4.

[0035] In the present embodiment, since the manifolds 50 and 51 have the same configuration, the following description will focus on the configuration of the manifold 50, and some description of the configuration of the manifold 51 may be omitted.

[0036] As shown in FIGS. 3 to 5, the manifold 50 includes a main body portion 501 and a flange portion 502.

[0037] A fluid to be measured flows from the outside into the main body 501. The main body 501 has, for example, a cylindrical shape. The main body 501 may also have a cylindrical shape as a base, with the outer diameter of a part of the main body 501 in the axial direction being reduced.

[0038] The component corresponding to the main body 501 in the manifold 51 causes the fluid to flow out to the outside.

[0039] Flange portion 502 is provided at the upper end of main body portion 501, and pipe portions 52a, 53a of sensor tubes 52, 53 are inserted and connected (fixed) by welding. Flange portion 502 has, for example, a disk shape. Furthermore, flange portion 502 may have a shape in which a part of the disk shape is cut out by two parallel chords when viewed from above.

[0040] In addition, the pipe sections 52b, 53b of the sensor tubes 52, 53 are inserted into the component section corresponding to the flange section 502 of the manifold 51 and are connected (fixed) thereto by welding.

[0041] Manifold 50 includes holes 503 to 505, a connection portion 506, a groove portion 507, a surface portion 508, and a groove portion 509.

[0042] Hole 503 is provided so as to extend upward from the lower end surface of main body 501. A conduit (not shown) is connected to hole 503, and a fluid to be measured flows in from the outside.

[0043] Hole 504 is provided to extend downward from the upper surface of flange 502. A base end of conduit 52a of sensor tube 52 is inserted into hole 504 from above.

[0044] Similar to hole 504, hole 505 is provided to extend downward from the upper surface of flange 502. A base end of conduit 53a of sensor tube 53 is inserted into hole 505 from above.

[0045] The holes 504, 505 are provided adjacent to each other in the front-rear direction on the upper surface of the flange portion 502. For example, the holes 504, 505 are adjacent to each other in the front-rear direction so as to be symmetrical with respect to the center of the arc of the outer periphery of the flange portion 502 in a top view.

[0046] The connecting portion 506 is disposed adjacent to the upper end of the hole portion 503 and the lower ends of the holes 504 and 505 vertically, and is a space for connecting the hole portion 503 and the holes 504 and 505 as a flow path. The connecting portion 506 is, for example, a cylindrical space.

[0047] The holes 503 to 505 and the connection portion 506 form the inlet portion 50a.

[0048] In the manifold 51, the components corresponding to the holes 503 to 505 and the connection portion 506 form an outflow portion 51a.

[0049] Groove portion 507 is formed on the upper surface of flange portion 502 so as to surround the entire periphery of holes 504 and 505. For example, groove portion 507 is configured by a combination of an arc-shaped groove portion centered on hole 504 and an arc-shaped groove portion centered on hole 505 when viewed from above.

[0050] Surface portion 508 is a portion of the upper surface of flange portion 502 where holes 504 and 505 are provided, and corresponds to a portion of the upper surface of flange portion 502 that is located more inward than groove portion 507 .

[0051] Groove portion 509 is provided on the upper surface of flange portion 502 so as to cross between hole portion 504 and hole portion 505. For example, groove portion 509 is formed so as to connect two connection portions, an arc-shaped groove portion in groove portion 507 centered on hole portion 504 and an arc-shaped groove portion centered on hole portion 505, to the left and right in a top view.

[0052] The depth of the groove 509 may be the same as that of the groove 507, or may be different.

[0053] The groove 509 separates the surface portion 508 into a surface portion 508a in which the hole 504 is provided and a surface portion 508b in which the hole 505 is provided.

[0054] [Welded part between manifold and sensor tube] Next, with reference to FIGS. 6 and 7 in addition to FIGS. 3 to 5, welds WD1 and WD2 formed by welding manifold 50 to sensor tubes 52 and 53 will be described.

[0055] Fig. 6 is a diagram showing experimental results of welding a manifold and a sensor tube according to a comparative example. Specifically, it is a diagram showing experimental results of welding a manifold and a sensor tube according to a comparative example in which groove portion 509 is omitted from manifold 50. Fig. 7 is a diagram showing experimental results of welding manifold 50 and sensor tubes 52, 53 according to the embodiment.

[0056] As described above, the manifolds 50, 51 have the same configuration, and therefore a description of the welded portions between the manifold 50 and the sensor tubes 52, 53 will be omitted.

[0057] 5, a weld WD1 joining the manifold 50 and the pipe line 52a is formed on the entire periphery of the surface portion 508a around the pipe line 52a of the sensor tube 52. Similarly, a weld WD2 joining the manifold 50 and the pipe line 53a is formed on the entire periphery of the surface portion 508b around the pipe line 53a of the sensor tube 53.

[0058] For example, groove 507 is set so that the distance between groove 507 and hole 504 on the upper surface of flange 502 is greater than the expected leg length of welded portion WD1. Similarly, groove 507 may be set so that the distance between groove 507 and hole 505 on the upper surface of flange 502 is greater than the expected leg length of welded portion WD2.

[0059] For example, as shown in Fig. 6, if groove 509 is not provided, overlap may occur between weld WD1 on the hole 504 side and weld WD2 on the hole 505 side in surface 508 between hole 504 and hole 505 (see the dotted circle in the figure). In this case, the overlap between welds WD1 and WD2 may become the starting point of a crack. In particular, when the fluid to be measured is the above-mentioned high-pressure gas, this possibility becomes very high, and as a result, there is a possibility that the device may not be able to handle the high-pressure gas.

[0060] Also, by ensuring a wide distance between the sensor tubes 52, 53, it is possible to suppress overlap between the welded part WD1 on the hole 504 side and the welded part WD2 on the hole 505 side. However, in this case, the vibrator 54 and the vibration pickups 55, 56 installed by being attached to both the sensor tubes 52, 53 may become larger, resulting in an increase in mass. Therefore, the additional mass added to the sensor tubes 52, 53 may cause the vibration of the sensor tubes 52, 53 by the vibrator 54 to become unstable, and as a result, the accuracy of the measurement results of the density and mass flow rate of the measured fluid may decrease.

[0061] In contrast, when groove portion 509 is provided as shown in FIG. 7, the distance between holes 504 and 505 is not increased, and weld portion WD1 on the hole 504 side is contained within surface portion 508a, and weld portion WD2 on the hole 505 side is contained within surface portion 508b.

[0062] In this manner, in this example, surface portion 508a and surface portion 508b are spaced apart from each other. This makes it possible to prevent overlap between welded portion WD1 on the hole 504 side and welded portion WD2 on the hole 505 side without increasing the distance between sensor tubes 52 and 53.

[0063] In this embodiment, grooves 509 are also provided. This allows the heat capacity of manifold 50 to be reduced. This reduces the amount of heat input required when welding sensor tubes 52, 53 and manifold 50. This makes it possible to prevent, for example, metal from melting into sensor tubes 52, 53 during welding.

[0064] [Other embodiments] Next, a vibration type measuring device 1 according to another embodiment will be described.

[0065] The vibration type measuring device 1 according to the above embodiment may be modified or changed as appropriate.

[0066] For example, in the above-described embodiment, the manifolds 50 and 51 may be integrated. In other words, instead of the manifolds 50 and 51, a manifold having both the inlet portion 50a and the outlet portion 51a for the fluid to be measured may be provided.

[0067] In the above-described embodiment and examples of modifications and variations thereof, the surface portion 508a where the hole portion 504 is provided and the surface portion 508b where the hole portion 505 is provided may be separated from each other by a method other than the method in which the groove portion 509 is provided so as to cross between the hole portion 504 and the hole portion 505. For example, the surface portion 508a and the surface portion 508b are formed so as to protrude from the basic surface of the upper end of the flange portion 502, thereby realizing an island-like structure in which the surface portions 508a and 508b are separated from each other. Also, instead of the groove portion 509, the surface portion 508a and the surface portion 508b may be separated from each other by providing a wall portion protruding upward at a similar position between the surface portion 508a and the surface portion 508b.

[0068] In the above-described embodiment and its modified and altered examples, surface portion 508a in which hole 504 is provided and surface portion 508b in which hole 505 is provided may be connected at other portions as long as hole 504, 505 are separated from each other. For example, in a direction perpendicular to the direction in which hole 504, 505 faces each other, groove 509 may be provided only in the range in which hole 504, 505 exists, and surface portions 508a, 508b may be connected in other ranges.

[0069] [Effect] Next, the operation of the Coriolis flowmeter according to this embodiment will be described.

[0070] In this embodiment, the Coriolis flowmeter includes a manifold, a pair of sensor tubes, an excitation unit, and a vibration sensor. The Coriolis flowmeter is, for example, the vibration type measuring device 1 described above. The manifold is, for example, the manifold 50, 51 described above. The pair of sensor tubes is, for example, the sensor tubes 52, 53 described above. The excitation unit is, for example, the vibrator 54 described above. The vibration sensor is, for example, the vibration pickup 55, 56 described above. Specifically, the manifold is provided with at least one of an inlet and an outlet for the fluid to be measured. The fluid to be measured is, for example, a high-pressure gas such as the above-mentioned CNG or hydrogen gas. The inlet and outlet are, for example, the above-mentioned inlet 50a and outlet 51a. The pair of sensor tubes are joined to the manifold by welding, and the fluid to be measured flows through them. The excitation unit vibrates the pair of sensor tubes in a direction to approach each other and in a direction to move away from each other. The vibration sensors are provided on the pair of sensor tubes on the upstream and downstream sides of the location where the excitation unit vibrates, and output a signal according to the relative displacement of the pair of sensor tubes. The manifold has a first hole into which one of the pair of sensor tubes is inserted and a second hole into which the other is inserted, and the first surface portion in which the first hole portion is provided and the second surface portion in which the second hole portion is provided are separated between the first hole portion and the second hole portion. The first hole portion and the second hole portion are, for example, the above-mentioned holes 504 and 505. The first surface portion and the second surface portion are, for example, the above-mentioned surfaces 508a and 508b.

[0071] This makes it difficult for a welded portion formed on the first surface portion between one sensor tube and the manifold to overlap with a welded portion formed on the second surface portion between the other sensor tube and the manifold, thereby making it possible to prevent overlapping between the welded portions between the manifold and each of the pair of sensor tubes.

[0072] In this embodiment, a first groove may be formed so as to cross between the first hole and the second hole. The first groove is, for example, groove 509.

[0073] This makes it possible to separate the first surface portion and the second surface portion by the first groove portion.

[0074] In this embodiment, a second groove may be formed so as to surround the first surface and the second surface. The second groove is, for example, the groove 507 described above.

[0075] This reduces the thermal capacity of the manifold, which in turn reduces the amount of heat input required to weld the pair of sensor tubes and the manifold together, thereby preventing, for example, metal from melting into the sensor tubes during welding.

[0076] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0077] 1. Vibration measuring device 50 Manifold 50a Inlet 51 Manifold 51a Outlet 52 Sensor tube 52a, 52b, 52c Pipe section 53 Sensor Tube 53a,53b,53c Pipe section 54 Vibrator 54b Magnet 55,56 Vibration pickup 501 Main body 502 Flange 503 Hole 504 Hole 507 Groove 508 Surface part 508a,508b Surface part 509 Groove WD1,WD2 welded section

Claims

1. a manifold provided with at least one of an inlet and an outlet for a fluid to be measured; a pair of sensor tubes joined to the manifold by welding and through which the fluid to be measured flows; an excitation unit that vibrates the pair of sensor tubes in directions toward and away from each other; a vibration sensor provided on each of the pair of sensor tubes on the upstream side and the downstream side of a portion where the vibration is applied by the excitation unit, the vibration sensor outputting a signal corresponding to a relative displacement of the pair of sensor tubes; the manifold has a first hole into which one of the pair of sensor tubes is inserted and a second hole into which the other is inserted, and a first surface portion on which the first hole is provided and a second surface portion on which the second hole is provided are spaced apart between the first hole and the second hole. Coriolis flowmeter.

2. A first groove is formed so as to cross between the first hole and the second hole.

2. The Coriolis flowmeter according to claim 1.

3. A second groove portion is formed so as to surround the first surface portion and the second surface portion.

3. The Coriolis flowmeter according to claim 2.

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