Centering device and flow meter unit

Abstract

The invention relates to a centering device and a flow meter unit. The centering device and the flow meter unit can restrain the central axis of an outflow and inflow port of a flow meter and the central axis of a flow path of a pipe connected with the flow meter from being staggered and restrain measurement precision from decreasing. The centering device (5) is provided with a plate-shaped plate part (51), the plate part is provided with an opening (52), the opening (52) is formed in a penetrating manner along a first direction which is the thickness direction, a cylindrical part for fluid to pass through is embedded into the inner side of the opening (52), a concave part (53) which is concave towards the center of the opening (52) is formed on the outer edge of the plate part (51), and a convex part (54) is formed on the bottom surface (53a) of the concave part (53).

Description

Technical Field

[0001] This invention relates to centering devices and flow meter units. Background Technology

[0002] There exists a flow meter having: an inlet that allows fluid to flow into its interior; and

[0003] The outlet is where fluid flows out from the inside, and the flow rate of the fluid passing through the inside is measured.

[0004] Piping connects to the inlet and outlet. If the central axis of the inlet is misaligned with the central axis of the flow path of the piping connected thereto, or if the central axis of the outlet is misaligned with the central axis of the flow path of the piping connected thereto, the fluid flow will become turbulent at this connection, causing flow deviation inside the flowmeter, and sometimes reducing measurement accuracy.

[0005] Therefore, Patent Document 1 discloses an example in which, in order to suppress the misalignment of the central axis, a clamp (centering device) is fixed to a beam that serves as a reference by using multiple clamping members that surround and support the piping and flow meter from the outside.

[0006] Patent Document 1: Japanese Utility Model Application Publication No. 5-40825

[0007] However, the allowable error for the dimensional and shape accuracy of piping is relatively large, and there are deviations for each product. Therefore, for piping and flow meters that are supported by clamps from the outside, deviations in the dimensions and shape can sometimes cause the central axes to misalign, resulting in a decrease in measurement accuracy. Summary of the Invention

[0008] The purpose of this invention is to obtain a centering device that can suppress the misalignment of the central axis of the flow meter's inlet and outlet with the central axis of the flow path of the piping connected to the flow meter, thereby suppressing a decrease in measurement accuracy.

[0009] The centering device of the present invention has a plate-shaped plate portion, which has an opening formed through a first direction which is the thickness direction and through which a cylindrical portion is embedded. A recess is formed on the outer edge of the plate portion toward the center of the opening, and a protrusion is formed on the bottom surface of the recess.

[0010] The effects of the invention

[0011] According to the present invention, a centering device is provided that can suppress the misalignment of the central axis of the flow meter's inlet / outlet and the central axis of the flow path of the piping connected to the flow meter, thereby suppressing a decrease in measurement accuracy. Attached Figure Description

[0012] Figure 1 This is a perspective view of the flow meter unit according to Embodiment 1.

[0013] Figure 2 This is observed from the outlet side of the flow meter. Figure 1 The exploded perspective view of the flow meter unit shown.

[0014] Figure 3 This is a perspective view of the centering device according to Embodiment 1.

[0015] Figure 4 This is a diagram showing the recessed portion of the centering device viewed along the first direction, illustrating, for example, a case where the outer diameter of the through bolt is smaller than the specified size due to error.

[0016] Figure 5 This is a diagram showing the recessed portion of the centering device viewed along the first direction, illustrating, for example, a case where the outer diameter of the through bolt is larger than the specified size due to error.

[0017] Figure 6 The diagram shows the first modified example of the convex part, and is a partial enlarged oblique view of the concave part.

[0018] Figure 7 The diagram shows the second variation of the convex portion, and is a magnified oblique view of the concave portion.

[0019] Figure 8 The diagram shows the third variation of the convex portion, and is a magnified oblique view of the concave portion.

[0020] Figure 9 The diagram shows the fourth variation of the convex portion, and is a magnified oblique view of the concave portion.

[0021] Figure 10 The diagram shows the fifth variation of the convex portion, and is a magnified oblique view of the concave portion. Detailed Implementation

[0022] The centering device and flow meter unit according to one embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Furthermore, the present invention is not limited to the embodiments described below.

[0023] [Implementation Method 1]

[0024] Figure 1 This is a perspective view of the flow meter unit according to Embodiment 1. The flow meter unit 1 includes a flow meter 2, a primary side piping unit 3, a secondary side piping unit 4, a centering device 5, and a through bolt 6.

[0025] Figure 2 This is observed from the outlet side of the flow meter. Figure 1The diagram shows an exploded perspective view of the flow meter unit. Flow meter 2 measures the flow rate of fluid passing through its interior. Flow meter 2 is a so-called wafer-type flow meter. Regarding the wafer-type flow meter 2, the flow meter 2 itself does not have a flange for connection to the piping; instead, the piping and flow meter 2 are connected by being clamped together by a flange on the piping side. Flow meter 2 is, for example, an electromagnetic flow meter, but is not limited to this. A cylindrical portion 24 is formed in the housing 21 of the flow meter 2, protruding in opposite directions. The inner side of the cylindrical portion 24 forms a flow path for fluid to flow in and out relative to the interior of the flow meter 2. The end of the flow path at the end face of the cylindrical portion 24 forms an outflow inlet 22 for fluid to flow in and out relative to the interior of the flow meter 2.

[0026] The outflow inlet 22 formed in one of the two cylindrical portions 24 becomes inlet 22a. The outflow inlet 22 formed in the other cylindrical portion 24 becomes outlet 22b. Furthermore, in... Figure 2 The end face of the cylindrical section 24 is not visible, and the inlet 22a is shown by a dashed line.

[0027] The inlet 22a and outlet 22b communicate with the interior of the housing 21. The inlet 22a is an opening for allowing fluid to flow into the interior of the housing 21. The outlet 22b is an opening for allowing fluid to flow out of the interior of the housing 21.

[0028] The cross-sectional shape of the flow path in the cylindrical section 24 is circular, and the shape of the outflow inlet 22 is also circular. The central axes of the flow paths of the two cylindrical sections 24 are aligned with each other. The direction in which this central axis extends is defined as the first direction. Figure 2 This is indicated by arrow X. Furthermore, the central axis of the outer surface of the cylindrical portion 24 coincides with the central axis of the flow path formed in the cylindrical portion 24.

[0029] The primary side piping unit 3 has a primary side piping 31 and a primary side flange 32. The primary side piping 31 is cylindrical in shape, and its inner side forms a flow path 31a through which fluid passes. The primary side piping 31 is a piping connected to the inlet 22a of the flow meter 2. Therefore, fluid flowing in the flow path 31a of the primary side piping 31 flows into the interior of the flow meter 2 through the inlet 22a.

[0030] A primary side flange 32 is provided at one end of the primary side piping 31. The primary side flange 32 is a plate-shaped component. The primary side flange 32 abuts against the end face of the cylindrical portion 24 where the inlet 22a is formed. A plurality of through holes 32a are formed in the primary side flange 32, extending parallel to the first direction when abutting against the end face of the cylindrical portion 24. Through bolts 6 penetrate the through holes 32a. The distance between the central axis of the plurality of through holes 32a formed in the primary side flange 32 and the central axis of the flow path 31a of the primary side piping 31 is equal.

[0031] The secondary piping unit 4 has a secondary piping 41 and a secondary flange 42. The secondary piping 41 is cylindrical, with its inner side forming a flow path 41a through which fluid passes. The secondary piping 41 is connected to the outlet 22b of the flow meter 2. Therefore, the fluid flowing in the flow path 41a of the secondary piping 41 is the fluid that flows out to the outside of the flow meter 2 through the outlet 22b.

[0032] A secondary side flange 42 is provided at one end of the secondary side piping 41. The secondary side flange 42 is a plate-shaped component. The secondary side flange 42 abuts against the end face of the cylindrical portion 24 where the outlet 22b is formed. A plurality of through holes 42a are formed in the secondary side flange 42, extending parallel to the first direction when abutting against the end face of the cylindrical portion 24. Through bolts 6 penetrate the through holes 42a. The distance between the central axis of the plurality of through holes 42a formed in the secondary side flange 42 and the central axis of the flow path 41a of the secondary side piping 41 is equal.

[0033] The through hole 32a formed in the primary side flange 32 and the through hole 42a formed in the secondary side flange 42 are formed in a position such that their central axes are aligned, with the primary side flange 32 and the secondary side flange 42 abutting against the end face of the cylindrical portion 24. This allows a single through bolt 6 to pass through both the through hole 32a and the through hole 42a.

[0034] With the through bolt 6 connecting the through hole 32a and the through hole 42a, screw the nut into the through bolt 6, thereby securing the primary side flange 32 and the secondary side flange 42, so that the primary side flange 32 and the secondary side flange 42 are in close contact with the end face of the cylindrical portion 24 of the flow meter 2.

[0035] Figure 3 This is a perspective view of the centering device. The centering device 5 has a plate portion 51 formed in the shape of a plate. The plate portion 51 is formed of resin, for example, but is not limited thereto. An opening 52 is formed in the plate portion 51. The opening 52 is formed through the thickness direction of the plate portion 51.

[0036] like Figure 1 and Figure 2 As shown, the centering device 5 causes the cylindrical portion 24 of the flow meter 2 to be inserted into the inside of the opening 52. In the following description, the state in which the cylindrical portion 24 of the flow meter 2 is inserted into the inside of the opening 52 is sometimes referred to as the state in which the centering device 5 is assembled with the flow meter 2.

[0037] With the centering device 5 assembled on the flow meter 2, the central axis of the flow path of the cylindrical part 24 coincides with the central axis of the opening 52. For example... Figure 1 and Figure 2As shown, with the centering device 5 assembled with the flow meter 2, the thickness direction of the plate portion 51 is aligned with the first direction indicated by arrow X. In the following description, when the term "first direction" is used to refer to the centering device 5, it indicates the first direction in the state where the centering device 5 is assembled with the flow meter 2.

[0038] On the outer edge of the plate portion 51, a plurality of recesses 53 are formed that are recessed toward the center of the opening 52. When the centering device 5 is assembled with the flow meter 2, the recesses 53 are formed into grooves extending in the first direction.

[0039] The bottom surface 53a of the recess 53 is arc-shaped when viewed along the first direction. Multiple protrusions 54 are formed on the bottom surface 53a of the recess 53. The protrusions 54 extend along the first direction. The multiple protrusions 54 are arranged circumferentially along the arc-shaped bottom surface 53a. Alternatively, it can be described as multiple protrusions 54 being arranged circumferentially along the opening 52. Figure 4 In the example shown, the arrangement forms 3 protrusions 54.

[0040] Centering devices 5 are respectively disposed between the flow meter 2 and the primary side flange 32 and between the flow meter 2 and the secondary side flange 42. When the centering devices 5 are assembled on the flow meter 2 and the primary side flange 32 and the secondary side flange 42 abut against the end face of the cylindrical portion 24 of the flow meter 2, a recess 53 is formed in such a way that the central axis of the bottom surface 53a, which is an arc surface, is aligned with the central axis of the through hole 32a and the through hole 42a.

[0041] The flowmeter unit 1 is assembled as follows: First, the centering device 5 is assembled to the flowmeter 2. Next, with the primary side flange 32 and the secondary side flange 42 abutting against the end faces of the cylindrical portion 24 of the flowmeter 2, the through bolt 6 passes through the through hole 32a, the through hole 42a, and the recess 53. Next, the nuts are screwed into both ends of the through bolt 6, thereby tightening the primary side flange 32 and the secondary side flange 42 to assemble the flowmeter unit 1. As a result, the primary side flange 32 and the secondary side flange 42 are in close contact with the end faces of the cylindrical portion 24 of the flowmeter 2.

[0042] Here, in order to prevent the flow measurement accuracy of flowmeter 2 from decreasing, it is necessary to suppress the flow deviation inside flowmeter 2. Flow deviation is generated by creating a step difference in the flow path at the connection between the primary side piping unit 3 and flowmeter 2, and at the connection between the secondary side piping unit 4 and flowmeter 2.

[0043] The step difference in the flow path occurs when the central axis of the flow path 31a of the primary side piping unit 3 is misaligned with the central axis of the flow path on the flow meter 2 side, which includes the inlet 22a, or the central axis of the flow path 41a of the secondary side piping unit 4 is misaligned with the central axis of the flow path on the flow meter 2 side, which includes the outlet 22b.

[0044] Regarding the outer diameter of the through bolt 6, the inner diameter of the through hole 32a formed in the primary side flange 32, the inner diameter of the through hole 42a formed in the secondary side flange 42, the distance between the central axis of the through hole 32a and the central axis of the flow path 31a, and the distance between the central axis of the through hole 42a and the central axis of the flow path 41a, permissible errors are set for each component according to each standard. Furthermore, in the following description, the permissible errors set for each standard regarding the outer diameter of the through bolt 6, the inner diameter of the through hole 32a formed in the primary side flange 32, the inner diameter of the through hole 42a formed in the secondary side flange 42, the distance between the central axis of the through hole 32a and the central axis of the flow path 31a, and the distance between the central axis of the through hole 42a and the central axis of the flow path 41a are simply referred to as "permissible errors of each component".

[0045] Even if the through bolt 6, primary side flange 32, and secondary side flange 42 are designed / manufactured in a manner that makes each central axis consistent, sometimes the central axis of the flow path 31a of the primary side piping unit 3 is misaligned with the central axis of the flow path on the flow meter 2 side, including the inlet 22a, or the central axis of the flow path 41a of the secondary side piping unit 4 is misaligned with the central axis of the flow path on the flow meter 2 side, including the outlet 22b.

[0046] The centering device 5 prevents the central axis of the flow path 31a of the primary side piping unit 3 from being misaligned with the central axis of the flow meter 2 side, which includes the inlet 22a, or the central axis of the flow path 41a of the secondary side piping unit 4 from being misaligned with the central axis of the flow meter 2 side, which includes the outlet 22b.

[0047] For example, regarding the centering device 5, when the through bolt 6, through hole 32a, and through hole 42a are all formed to specified dimensions, the position for the outer peripheral surface of the through bolt 6 to pass through is designed to be between the bottom surface 53a of the recess 53 and the top surface of the protrusion 54.

[0048] Figure 4 This is a diagram showing the recessed portion of the centering device viewed along the first direction, illustrating an example where the outer diameter of the through bolt is smaller than the specified size due to error. When the outer diameter of the through bolt 6 is smaller than the specified size, the protrusion 54 formed on the bottom surface 53a of the recess 53 of the centering device 5 positions the through bolt 6 at a position separated from the bottom surface 53a.

[0049] Therefore, the position of the central axis of the through bolt 6 with an outer diameter smaller than the specified size can be aligned with the position of the central axis of the through bolt 6 when using a through bolt 6 formed to the specified size.

[0050] Figure 5 This diagram shows the recessed portion of the centering device viewed along the first direction, illustrating an example where the outer diameter of the through bolt is larger than the specified size due to error. When the outer diameter of the through bolt 6 is larger than the specified size, and the through bolt 6 passes through both the through hole 32a and the through hole 42a, and the nut is screwed into the through bolt 6, the protrusion 54 formed on the bottom surface 53a of the recess 53 of the centering device 5 is ground by the outer peripheral surface of the through bolt 6. By grinding the protrusion 54, the through bolt 6 is positioned close to the bottom surface 53a.

[0051] Therefore, the position of the central axis of the through bolt with an outer diameter greater than the specified size can be aligned with the position of the central axis of the through bolt 6 when using the through bolt 6 formed to the specified size.

[0052] As described above, the position of the central axis can be aligned even when using a through bolt 6 that is smaller than the specified size or when using a through bolt 6 that is larger than the specified size. As a result, the primary side flange 32 and the secondary side flange 42 fastened by the through bolt 6 can be positioned more accurately.

[0053] This prevents the central axis of the flow path 31a of the primary side piping unit 3 from being misaligned with the central axis of the flow meter 2 side, including the inlet 22a, or the central axis of the flow path 41a of the secondary side piping unit 4 from being misaligned with the central axis of the flow meter 2 side, including the outlet 22b, thus suppressing the generation of internal flow deviation in the flow meter 2. By suppressing the generation of internal flow deviation in the flow meter 2, the decrease in the measurement accuracy of the flow meter 2 can be suppressed.

[0054] Here, the outer diameter of the through bolt 6 is used as an example for explanation. However, when the inner diameters of the through holes 32a and 42a differ from the specified dimensions, the through bolt 6 is positioned close to the position where the through holes 32a and 42a are formed with the specified dimensions by supporting the through bolt 6 with the protrusion 54 or by grinding the protrusion 54. Furthermore, when the distance between the central axis of the through hole 32a and the central axis of the flow path 31a, and the distance between the central axis of the through hole 42a and the central axis of the flow path 41a differ from the specified dimensions, the through bolt 6 is positioned even closer to the position where the through holes 32a and 42a are formed with the specified dimensions by supporting the through bolt 6 with the protrusion 54 or by grinding the protrusion 54.

[0055] Furthermore, the tolerances of the aforementioned components are typically smaller than the tolerances of the outer diameters of the primary side piping 31 and the secondary side piping 41. Therefore, compared to the case where multiple clamping members that surround and support the primary side piping 31 and the secondary side piping 41 from the outside are fixed to a beam serving as a reference to suppress misalignment of the central axis, the centering device 5 can suppress central axis misalignment with higher precision.

[0056] Furthermore, the maximum conceivable value of the misalignment between the central axis of the flow path 31a of the primary side piping unit 3 and the central axis of the flow meter 2 side including the inlet 22a, and the misalignment between the central axis of the flow path 41a of the secondary side piping unit 4 and the central axis of the flow meter 2 side including the outlet 22b, is calculated based on the cumulative allowable errors of the aforementioned components.

[0057] The tolerance varies depending on the standards followed by each component. For example, the flow meter 2 follows the standards ASME Class 150, ASM Class 300, EN PN 10, EN PN 16, EN PN 40, JIS F12, JIS10K, and JIS20K.

[0058] Based on the allowable error specified in the above standard, the maximum misalignment of the central axis is 1.2 mm to 1.8 mm. Therefore, it is preferable that the height of the protrusion 54 relative to the bottom surface 53a is less than or equal to 1.8 mm.

[0059] Furthermore, the height of the protrusion 54 formed between two of the three protrusions 54 can be lower than the height of the protrusions 54 formed on both sides. In this case, the circumferential through bolts 6 of the bottom surface 53a are positioned by the protrusions 54 formed on both sides, and the protrusion 54 formed in the middle is ground as needed by the radial through bolts 6 of the bottom surface 53a. Furthermore, examples of forming lower-height protrusions 54 are not limited to the above examples. For example, the number of protrusions 54 is not limited to three, but can be greater than or equal to four. Additionally, the number of lower-height protrusions 54 is not limited to one, and the height of multiple protrusions 54 can be reduced. Furthermore, when five or more protrusions 54 are provided, the protrusions 54 closer to the center can be formed with a lower height. That is, it is sufficient to form a protrusion 54 with a lower height than the aforementioned protrusions 54 between at least two protrusions 54. Alternatively, multiple lower-height protrusions 54 can be formed between the two protrusions 54. The lower-height protrusions can have the same height or different heights from each other.

[0060] Figure 6 This is a diagram showing the first variation of the convex portion, and it is a magnified oblique view of the concave portion. (See diagram below.) Figure 6As shown, a protrusion 54 can be formed on the bottom surface 53a of the recess 53.

[0061] Figure 7 This is a diagram showing the second variation of the convex portion, and it is a magnified oblique view of the concave portion. (See diagram below.) Figure 7 As shown, five protrusions 54 can be formed on the bottom surface 53a of the recess 53. Furthermore, the number of protrusions is not limited to five; it can be four, or more than or equal to six.

[0062] Figure 8 This is a diagram showing the third variation of the convex portion, and it is a magnified oblique view of the concave portion. (See diagram below.) Figure 8 As shown, a protrusion 54 can be formed on the bottom surface 53a of the recess 53 in a manner that extends circumferentially along the bottom surface 53a.

[0063] Figure 9 This is a diagram showing the fourth variation of the convex portion, and it is a magnified oblique view of the concave portion. (See diagram below.) Figure 9 As shown, a plurality of protrusions 54 extending circumferentially along the bottom surface 53a can be formed on the bottom surface 53a of the recess 53.

[0064] Figure 10 This is the fifth variation of the convex portion, and it is a magnified oblique view of the concave portion. (See diagram below.) Figure 10 As shown, a plurality of protrusions 54 can be formed on the bottom surface 53a of the recess 53, in the circumferential direction and the first direction of the bottom surface 53a. The shape of the protrusions 54 can be, for example, a cone shape, a cube shape, or a cuboid shape.

[0065] <Summary of Results>

[0066] The centering device 5 has a plate-shaped plate portion 51, which has an opening 52 formed in the inner side of which a cylindrical portion 24 is embedded and is formed through a first direction that is the thickness direction and is for fluid to pass through. A recess 53 is formed on the outer edge of the plate portion 51 and is recessed toward the center of the opening 52. A protrusion 54 is formed on the bottom surface 53a of the recess 53.

[0067] The protrusion 54 is ground based on the errors in the inner diameter of the through holes 32a and 42a formed on the flanges 32 and 42 that abut against the end face of the cylindrical part 24, the error in the outer diameter of the through bolt 6, the error in the distance between the central axis of the through hole 32a and the central axis of the flow path 31a, and the error in the distance between the central axis of the through hole 42a and the central axis of the flow path 41a. This can suppress the misalignment of the central axis of the flow inlet 22 of the flow meter and the central axis of the flow path of the pipe connected to the flow meter 2, thereby suppressing the decrease in the measurement accuracy of the flow meter.

[0068] The protrusion 54 can extend parallel to the first direction. This prevents the protrusion 54 from getting into the groove portion of the thread teeth formed on the outer side of the through bolt 6, and the through bolt 6 is stably supported by the protrusion 54.

[0069] Multiple protrusions 54 can be arranged in a circumferential direction on the bottom surface 53a of the recess 53. By forming multiple protrusions 54, the through bolts 6 supported on the protrusions 54 are less likely to be misaligned in the circumferential direction on the bottom surface 53a. In addition, the ease of grinding of the protrusions 54 can be adjusted according to the number of protrusions 54 formed.

[0070] Three protrusions 54 can be formed, and the height of the protrusion 54 formed between two protrusions 54 can be lower than the height of the protrusions 54 formed on both sides. Thus, the through bolt 6 is positioned in the circumferential direction of the bottom surface 53a by the protrusions 54 formed on both sides, and the protrusion 54 formed in the middle is ground as needed by the radial positioning of the through bolt 6 on the bottom surface 53a.

[0071] The protrusion 54 can extend circumferentially parallel to the bottom surface 53a of the recess 53. Even the protrusion 54 extending circumferentially parallel to the bottom surface 53a can support the through bolt 6 or be ground as needed.

[0072] Multiple protrusions 54 can be arranged in the first direction. The grinding ease of the protrusions 54 can be adjusted according to the number of protrusions 54 formed.

[0073] Multiple protrusions 54 can be formed by arranging them in the first direction and circumferentially around the bottom surface of the recess 53. By arranging multiple protrusions 54 in the first direction and circumferentially around the bottom surface of the recess 53, the range of adjustment for the ease of grinding of the protrusions 54 can be expanded according to the number of protrusions 54 and their formation positions.

[0074] The height of the protrusion 54 relative to the bottom surface 53a of the recess 53 can be less than or equal to 1.8 mm. If the protrusion 54 is too high, the resistance when the through bolt 6 is driven through will increase, sometimes reducing work efficiency or preventing the through bolt 6 from being driven through. Considering the standard to which the flow meter 2 is based, by making the height of the protrusion 54 less than or equal to 1.8 mm, it is possible to prevent the resistance when the through bolt 6 is driven through from becoming too high.

[0075] The flow meter unit 1 includes: a flow meter 2 having a cylindrical portion 24 protruding from the housing 21 in opposite directions, an inlet / outlet 22 formed on the end face of the cylindrical portion 24 for allowing fluid to flow in or out relative to the interior of the housing 21, and for measuring the flow rate of fluid passing through the interior; and a centering device 5 having a plate-shaped plate portion 51 having an opening 52 formed in a first direction that is the thickness direction and into which the cylindrical portion 24 is embedded, a recess 53 formed on the outer edge of the plate portion 51 that is recessed toward the center of the opening 52, and a protrusion 54 formed on the bottom surface 53a of the recess 53. Additionally, it may include: a pair of flanges 32, 42 having through holes 32a, 42a that abut against the end face of the cylindrical portion 24 and extend in the first direction; and a through bolt 6 that passes through the through holes 32a, 42a and the recess 53 to fasten the pair of flanges 32, 42.

[0076] The protrusion 54 is ground according to the error of the inner diameter of the through holes 32a, 42a of the flanges 32, 42 that abut against the end face of the cylindrical part 24 and the outer diameter of the through bolt 6. This can suppress the misalignment of the central axis of the flow inlet 22 of the flow meter and the central axis of the flow path of the pipe connected to the flow meter 2, thereby suppressing the decrease in the measurement accuracy of the flow meter.

[0077] [other]

[0078] The following are some examples of combinations of publicly disclosed technical features.

[0079] (1) A centering device, wherein,

[0080] The centering device has a plate-shaped plate portion with an opening formed inside a cylindrical portion through which fluid passes, forming a first direction that is the thickness direction. A recess is formed on the outer edge of the plate portion toward the center of the opening, and a protrusion is formed on the bottom surface of the recess.

[0081] (2) According to the centering device described in (1) above, wherein,

[0082] The protrusion extends parallel to the first direction.

[0083] (3) According to the centering device described in (2) above, wherein,

[0084] The protrusions are arranged in a plurality of circumferential directions on the bottom surface of the concave portion.

[0085] (4) According to the centering device described in (3) above, wherein,

[0086] The plurality of protrusions includes a protrusion formed at a height lower than that of the adjacent protrusions.

[0087] (5) According to the centering device described in (4) above, wherein,

[0088] The protrusion is formed in three parts, and the height of the protrusion formed between two of the protrusions is lower than the height of the protrusions formed on both sides.

[0089] (6) According to the centering device described in (1) above, wherein,

[0090] The convex portion extends circumferentially parallel to the bottom surface of the concave portion.

[0091] (7) The centering device described in (6) above, wherein,

[0092] The protrusions are arranged in a plurality of forms in the first direction.

[0093] (8) The centering device described in (1) above, wherein,

[0094] The protrusions are arranged in a plurality of circumferential directions in the first direction and on the bottom surface of the recess.

[0095] (9) The centering device described in any one of (1) to (8) above, wherein,

[0096] The height of the convex portion from the bottom surface of the concave portion is less than or equal to 1.8 mm.

[0097] (10) A flow meter unit, wherein,

[0098] The flow meter unit includes: a flow meter having a cylindrical portion protruding from the housing in opposite directions, an inlet / outlet formed on the end face of the cylindrical portion for fluid to flow in or out relative to the interior of the housing, for measuring the flow rate of fluid passing through the interior; and a centering device having a plate-shaped plate portion having an opening formed through the cylindrical portion along a first direction which is the thickness direction and into which the cylindrical portion is embedded, a recess formed on the outer edge of the plate portion toward the center of the opening, and a protrusion formed on the bottom surface of the recess.

[0099] (11) According to the flow meter unit described in (10) above, wherein,

[0100] The flow meter unit further comprises: a pair of flanges that abut against the end face of the cylindrical portion and form a through hole extending along the first direction; and a through bolt that passes through the through hole and the recess to fasten the pair of flanges.

[0101] Explanation of the label

[0102] 1 Flowmeter Unit

[0103] 2 Flowmeter

[0104] 21. Shell

[0105] 22 Outlet and inlet

[0106] 22a Flow Inlet

[0107] 22b outlet

[0108] 24 cylindrical part

[0109] 3 Primary side piping unit

[0110] 31 Primary side piping

[0111] 31a flow path

[0112] 32 Primary side flange

[0113] 32a Through Hole

[0114] 4 Secondary side piping units

[0115] 41 Secondary side piping

[0116] 41a flow path

[0117] 42 secondary side flanges

[0118] 42a Through Hole

[0119] 5. Centering equipment

[0120] 51 Plate section

[0121] 52 Opening

[0122] 53 recess

[0123] 53a bottom

[0124] 54 bulge

[0125] 6 Through bolts

Claims

1. A centering device, wherein, The centering device has a plate-shaped plate portion, which has an opening formed inside a cylindrical portion that extends through along a first direction, which is the thickness direction, and allows fluid to pass through. A recess is formed on the outer edge of the plate portion, which is recessed toward the center of the opening. A protrusion is formed on the bottom surface of the concave portion.

2. The centering device according to claim 1, wherein, The protrusion extends parallel to the first direction.

3. The centering device according to claim 2, wherein, The protrusions are arranged circumferentially on the bottom surface of the concave portion to form multiple protrusions.

4. The centering device according to claim 3, wherein, The plurality of protrusions includes a protrusion formed at a height lower than that of the adjacent protrusions.

5. The centering device according to claim 4, wherein, The protrusion is formed in three parts, and the height of the protrusion formed between two of the protrusions is lower than the height of the protrusions formed on both sides.

6. The centering device according to claim 1, wherein, The convex portion extends circumferentially parallel to the bottom surface of the concave portion.

7. The centering device according to claim 6, wherein, The protrusions are arranged in a plurality of forms in the first direction.

8. The centering device according to claim 1, wherein, The protrusions are arranged in a plurality of circumferential directions in the first direction and on the bottom surface of the recess.

9. The centering device according to any one of claims 1 to 8, wherein, The height of the convex portion from the bottom surface of the concave portion is less than or equal to 1.8 mm.

10. A flow meter unit, wherein, The flow meter unit has: A flow meter having cylindrical portions protruding from a housing in opposite directions, with inlet and outlet portions formed on the end faces of the cylindrical portions to allow fluid to flow in or out of the housing relative to the interior, and measuring the flow rate of fluid passing through the interior. as well as A centering device having a plate-shaped plate portion having an opening formed through a first direction which is the thickness direction and into which the cylindrical portion is embedded, a recessed portion formed at the outer edge of the plate portion toward the center of the opening, and a protrusion formed on the bottom surface of the recessed portion.

11. The flow meter unit according to claim 10, wherein, The flow meter unit also has: A pair of flanges abutting against the end face of the cylindrical portion and forming a through hole extending along the first direction; and A through bolt, which passes through the through hole and the recess to fasten the pair of flanges.

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