Gas meter

Abstract

To provide a gas meter capable of improving measurement accuracy.SOLUTION: A gas meter 100 includes: a measurement unit 14 having a measurement unit side connection surface 65 surrounding the exit of a measurement passage 54 and positioned on a plane intersecting the flow direction DF of a fluid to be measured and for measuring the flow rate of the fluid to be measured flowing into the measurement passage 54; a connection fitting 15 communicating with an outflow port 27 to define a connection passage 81 into which the fluid to be measured flows and having a connection fitting side connection surface 87 facing the measurement unit side connection surface 65 and surrounding the inlet port of the connection passage 81; a planar seal member 16 positioned to be sandwiched by the measurement unit side connection surface 65 and the connection fitting side connection surface 87 and facing a space connecting the measurement passage 54 and the connection passage 81; and a fixture for fixing the measurement unit 14 to the connection fitting 15 to maintain the state of pressing the measurement unit side connection surface 65 and the connection fitting side connection surface 87 by a predetermined surface pressure though the planar seal member 16.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas meter. [Background technology]

[0002] As a gas meter, for example, the gas meter shown in Patent Document 1 is known.

[0003] This gas meter includes a flow rate measurement unit and a connecting member. The connecting member is provided with an attachment portion into which the rectangular outlet of the flow rate measurement unit is inserted. An annular seal member is disposed between the outer periphery of the flow rate measurement unit and the inside of the attachment portion of the connecting member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-156100 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the gas meter described in Patent Document 1, the annular sealing member is pulled locally at the corner of the rectangular outlet of the flow rate measuring unit, which can result in the sealing member not being compressed sufficiently and causing leakage. As a result, the flow rate cannot be measured accurately and measurement accuracy can be reduced. [Means for solving the problem]

[0006] In order to solve the above problems, a gas meter according to one aspect of the present invention includes a meter box having an internal space, a meter inlet section having an inlet through which a fluid to be measured flows into the meter box, a meter outlet section having an outlet through which the fluid to be measured that has flowed into the meter inlet section flows out of the meter box, a flow path forming section that is housed in the meter box and defines a measurement flow path through which the fluid to be measured flows, and a measurement unit side connection surface that surrounds the outlet of the measurement flow path and is located on a plane that intersects with the flow direction of the fluid to be measured, and the flow rate of the fluid to be measured that flows through the measurement flow path is measured. the connection fitting defining a connection flow path that communicates with the outlet and through which the fluid to be measured flows, the connection fitting having a connection joint side connection surface that faces the measurement unit side connection surface and surrounds the inlet of the connection flow path; a flat seal member that is positioned between the measurement unit side connection surface and the connection joint side connection surface and faces the space that connects the measurement flow path and the connection flow path; and a fixture that fixes the measurement unit to the connection fitting and maintains the measurement unit side connection surface and the connection joint side connection surface in a pressed state with a predetermined surface pressure via the flat seal member.

[0007] According to this configuration, the connecting surface on the measurement unit side and the connecting surface on the connection joint side can be maintained in a state of being pressed against each other with a uniform predetermined surface pressure via the flat seal member, thereby suppressing leakage of the fluid to be measured and improving measurement accuracy. [Effects of the Invention]

[0008] The present invention has an effect of improving measurement accuracy. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an example of the configuration of a gas meter according to a first embodiment. [Figure 2] 2 is an exploded perspective view showing an example of the configuration of a measurement unit and a connection joint of the gas meter of FIG. 1. FIG. [Figure 3] FIG. 2 is a perspective view showing an example of the configuration of a main body block of the gas meter of FIG. [Figure 4] 2 is an enlarged cross-sectional view of a main part showing a configuration example of a connection structure between a measurement unit of the gas meter of FIG. 1 and a connection joint, the cross-sectional view being taken along a plane extending along the flow direction and the short-side direction. FIG. [Figure 5] 2 is an enlarged cross-sectional view of a main part showing an example of the configuration of the connection structure between the measurement unit of the gas meter of FIG. 1 and the connection joint, the cross-sectional view being taken on a plane passing through the fixed axis and extending along the longitudinal and lateral directions. FIG. [Figure 6] FIG. 10 is a perspective view showing a configuration example of a measurement unit and a connection joint of a gas meter according to a second embodiment. [Figure 7] FIG. 7 is a perspective view showing an example of the configuration of a connection joint of the gas meter of FIG. 6. [Figure 8] FIG. 7 is a perspective view showing an example of the configuration of a measurement unit of the gas meter of FIG. 6. [Figure 9] FIG. 11 is a perspective view showing a configuration example of a connection joint of a gas meter according to a third embodiment. [Figure 10] 10A to 10C are diagrams showing an example of the configuration of a measurement unit of a gas meter according to a fourth embodiment, and are, from top to bottom, a front view, a rear view, a plan view, and a bottom view. [Figure 11] 11A and 11B are diagrams showing an example of the configuration of the measurement unit of FIG. 10, and are, from top to bottom, a left side view, a right side view, and a perspective view 1. FIG. [Figure 12] 11A and 11B are diagrams showing an example of the configuration of the measurement unit of FIG. 10, and are, from above, a perspective view 2 and a reference perspective view showing a state of use. [Figure 13] 10A to 10C are diagrams showing an example of the configuration of a measurement unit of a gas meter according to a fifth embodiment, and are, from top to bottom, a front view, a rear view, a plan view, and a bottom view. [Figure 14] 14A and 14B are diagrams showing an example of the configuration of the measurement unit of FIG. 13, and are, from top to bottom, a left side view, a right side view, and a perspective view 1. FIG. [Figure 15] 14 is a diagram showing an example of the configuration of the measurement unit of FIG. 13, and is, from the top, a perspective view 2 and a reference perspective view 1 showing the state of use. [Figure 16] FIG. 14 is a diagram showing a configuration example of the measurement unit of FIG. 13, and is a reference perspective view 2 showing the state of use. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments. In addition, the same or corresponding elements will be denoted by the same reference numerals throughout the drawings, and redundant description will be omitted.

[0011] (Embodiment 1) FIG. 1 is a cross-sectional view showing an example of the configuration of a gas meter 100 according to the first embodiment.

[0012] As shown in Fig. 1, the gas meter 100 is a flow measurement device that can measure the flow rate of a fluid to be measured, such as city gas or liquefied petroleum gas. The measured flow rate of the fluid to be measured can be used as the basis for calculating fees. In this embodiment, the gas meter 100 is suitable for industrial use (business use) and is compatible with higher flow rates than those for residential use.

[0013] The gas meter 100 includes a meter box 11 , a meter inlet 12 , a meter outlet 13 , a meter unit 14 , a connection joint 15 , and a shutoff valve 19 .

[0014] The metering box 11 is a container that forms the outer shell of the gas meter 100. The metering box 11 has an internal space 24 that is filled with gas.

[0015] Meter inlet portion 12 is a mouthpiece connected to a gas supply pipe, and is the portion through which the fluid to be measured is introduced into internal space 24 of metering box 11. Meter inlet portion 12 has inlet 26. Inlet 26 is an opening through which the fluid to be measured flows into metering box 11.

[0016] Meter outlet 13 is a nozzle that is connected to the building's piping, and is the part that discharges the fluid to be measured that has been measured by measurement unit 14 to the outside. Meter outlet 13 has outlet 27. Outlet 27 is an opening through which the fluid to be measured that has flowed into meter inlet 12 flows out of meter box 11.

[0017] The measuring unit 14 is a measuring unit that measures the flow rate of the fluid to be measured. The measuring unit 14 is housed in the measuring box 11. In this embodiment, the measuring unit 14 is an ultrasonic measuring unit that transmits and receives ultrasonic waves between two ultrasonic transmitter / receivers 32, measures the propagation time of the ultrasonic waves, measures the flow rate of the fluid to be measured, and outputs the measured flow rate.

[0018] The connection joint 15 is a joint that connects the measurement unit 14 and the meter outlet portion 13 .

[0019] The shutoff valve 19 is attached to the meter inlet portion 12, and shuts off the inflow of the fluid to be measured into the measurement box 11 when the control portion of the gas meter 100 determines that there is an abnormality such as a gas leak.

[0020] Next, a detailed description will be given of the measurement unit 14, the connection joint 15, and the connection structure between the measurement unit 14 and the connection joint 15. FIG.

[0021] <Measurement unit> The measurement unit 14 includes a main body block 31, a circuit board fixing portion 34, a pin 70 for attaching the circuit board fixing portion 34 to the main body block 31, two ultrasonic transmitter / receivers 32, a circuit board 33, two ultrasonic transmitter / receiver fixing devices 35, and a cover 74.

[0022] Fig. 3 is a perspective view showing an example of the configuration of the main body block 31. The main body block 31 is a member integrally formed from a resin material. As shown in Fig. 3, the main body block 31 includes a flow path forming section 41, a plurality of partition plates 47, two ultrasonic transmitter / receiver holding sections 43, two transmission sections 42, and an attachment section 44.

[0023] The flow path forming portion 41 surrounds a measurement flow path 54 through which the fluid to be measured flows, and defines the measurement flow path 54. The flow path forming portion 41 includes a wall portion 55, which is a cylindrical body extending in the flow direction DF of the fluid to be measured, and a funnel portion 45. The wall portion 55 has a substantially rectangular cross section with respect to the flow direction DF, and has a longitudinal direction DL and a lateral direction DS. The longitudinal direction DL is a direction that intersects or is perpendicular to the flow direction DF. The lateral direction DS is a direction that intersects or is perpendicular to the flow direction DF and the longitudinal direction DL. The wall portion 55 includes a first longitudinal wall portion 51, a second longitudinal wall portion 52, and two side wall portions 53. The cross-sectional area of ​​the measurement flow path 54 is, for example, 400 mm 2 As a result, the cross-sectional area is larger than that of a gas meter for home use.

[0024] The first longitudinal wall 51 is a wall extending in the longitudinal direction DL when viewed from the flow direction DF. In this embodiment, the first longitudinal wall 51 is located on a plane extending in the longitudinal direction DL and the flow direction DF. The second longitudinal wall 52 is a wall extending parallel to the first longitudinal wall 51 and facing the first longitudinal wall 51. The two side wall 53 are walls extending in the lateral direction DS when viewed from the flow direction DF. In this embodiment, the two side wall 53 are located on a plane extending in the lateral direction DS and the flow direction DF. One side wall 53 connects one side edge of the two first longitudinal wall 51. The other side wall 53 connects the other side edge of the two first longitudinal wall 51.

[0025] The funnel portion 45 is located at the upstream end of the flow path forming portion 41 in the flow direction DF. The measurement flow path 54 has a shape in which the cross-sectional area decreases from the upstream side to the downstream side in the flow direction DF of the measurement flow path 54, causing the measurement target fluid to contract from the upstream side to the downstream side in the flow direction DF. The funnel portion 45 has the effect of suppressing turbulence in the measurement target fluid and making the flow velocity distribution uniform. As a result, the funnel portion 45 contributes to improving measurement accuracy.

[0026] The partition plates 47 are disposed between the two side wall portions 53 and are each a plate-like body extending in the flow direction DF. The partition plates 47 are arranged in the longitudinal direction DL. By dividing the internal space in the measurement flow path 54, the partition plates 47 have the effect of suppressing turbulence in the fluid to be measured and making the flow velocity distribution uniform. As a result, the partition plates 47 contribute to improving measurement accuracy.

[0027] The two ultrasonic transmitter / receiver holding parts 43 are arranged on the first longitudinal wall part 51. The ultrasonic transmitter / receiver holding parts 43 are formed in a short cylindrical shape protruding from the first longitudinal wall part 51, with a base end connected to the first longitudinal wall part 51 and a tip end forming a holding part 59 that holds the ultrasonic transmitter / receiver 32. The two ultrasonic transmitter / receiver holding parts 43 are aligned in the flow direction DF. One of the two ultrasonic transmitter / receiver holding parts 43 holds the ultrasonic transmitter / receiver 32 so that the wave transmission direction of the ultrasonic transmitter / receiver 32 faces toward the second longitudinal wall part 52 and downstream. The other of the two ultrasonic transmitter / receiver holding parts 43 holds the ultrasonic transmitter / receiver 32 so that the wave transmission direction of the ultrasonic transmitter / receiver 32 faces toward the second longitudinal wall part 52 and upstream. The internal space of the ultrasonic transmitter / receiver holding portion 43 forms an ultrasonic wave propagation portion 61, which is a space through which the ultrasonic waves transmitted from the ultrasonic transmitter / receiver 32 propagate.

[0028] The two transmission sections 42 are openings formed in the first longitudinal wall section 51. The two transmission sections 42 are positioned side by side in the flow direction DF of the fluid to be measured. The two transmission sections 42 are positioned between the ultrasonic propagation section 61 and the measurement flow path 54, and communicate with the ultrasonic propagation section 61 and the measurement flow path 54. The two transmission sections 42 each form a space through which ultrasonic waves transmitted and received from the ultrasonic transmitter / receiver 32 propagate.

[0029] The ultrasonic waves transmitted by the upstream ultrasonic transmitter / receiver 32 pass through the upstream ultrasonic propagation portion 61 and the transmission portion 42, enter the measurement flow path 54, and are reflected at least once by the inner surface of the second longitudinal wall portion 52. The ultrasonic waves reflected by the second longitudinal wall portion 52 then pass through the downstream transmission portion 42 from the measurement flow path 54, enter the downstream ultrasonic propagation portion 61, and are detected by the downstream ultrasonic transmitter / receiver 32. The ultrasonic waves transmitted by the downstream ultrasonic transmitter / receiver 32 also pass through the downstream ultrasonic propagation portion 61 and the transmission portion 42, enter the measurement flow path 54, and are reflected at least once by the second longitudinal wall portion 52. The ultrasonic waves reflected by the second longitudinal wall portion 52 then pass through the upstream transmission portion 42 from the measurement flow path 54, enter the upstream ultrasonic propagation portion 61, and are detected by the upstream ultrasonic transmitter / receiver 32.

[0030] The mounting portion 44 is a portion to which the circuit board fixing portion 34 is attached and which holds the circuit board fixing portion 34. The mounting portion 44 is located between the two ultrasonic transmitter / receiver holding portions 43. The mounting portion 44 has an engagement shaft 67 that protrudes outward from the outer surface of the first longitudinal wall portion 51. The engagement shaft 67 has a pin insertion hole 68 formed at its tip. The pin insertion hole 68 is a through hole that extends in a direction that intersects or is perpendicular to the engagement shaft 67.

[0031] As shown in FIG. 2 , the circuit board fixing portion 34 is a member that holds the circuit board 33. The circuit board fixing portion 34 is a member that is independent from the main body block 31. The circuit board fixing portion 34 has an engagement hole 69 through which an engagement shaft 67 is inserted. When the circuit board fixing portion 34 is attached to the attachment portion 44, the tip of the engagement shaft 67 of the attachment portion 44 and the pin insertion hole 68 protrude outward from the engagement hole 69 of the circuit board fixing portion 34. A pin 70, which is a snap pin, is removably attached to the pin insertion hole 68. This restricts movement of the circuit board fixing portion 34 and fixes it to the main body block 31.

[0032] The ultrasonic transmitter / receiver 32 includes an ultrasonic transmitting element. When a drive signal is input to the ultrasonic transmitting element, the element transmits ultrasonic waves in a predetermined transmitting direction in response to the drive signal to the outside. When an ultrasonic wave is received from the outside, the ultrasonic oscillation element outputs a detection voltage in response to the received ultrasonic waves. As such an ultrasonic oscillation element, a known ultrasonic oscillation element can be used, such as a known piezoelectric ceramic vibrator.

[0033] The circuit board 33 is connected to the two ultrasonic transmitter / receivers 32 via lead wires. The circuit board 33 drives the two ultrasonic transmitter / receivers 32. The circuit board 33 includes a measurement unit and a calculation unit. The measurement unit measures the propagation time of ultrasonic waves from one ultrasonic transmitter / receiver 32 to the other ultrasonic transmitter / receiver 32. More specifically, the measurement unit measures a first propagation time of ultrasonic waves traveling from the upstream ultrasonic transmitter / receiver 32 to the downstream ultrasonic transmitter / receiver 32, and a second propagation time of ultrasonic waves traveling from the downstream ultrasonic transmitter / receiver 32 to the upstream ultrasonic transmitter / receiver 32. The calculation unit calculates the flow rate of the fluid to be measured flowing through the measurement flow path 54 based on the propagation times measured by the measurement unit. More specifically, the difference between the first propagation time and the second propagation time is proportional to the flow velocity of the fluid to be measured. Therefore, the calculation unit calculates the flow velocity based on the difference between the first propagation time and the second propagation time, and calculates the flow rate by multiplying the calculated flow velocity by the known cross-sectional area of ​​the measurement flow path 54. The circuit board 33 is disposed parallel to the flow direction DF and is positioned so as to straddle the two ultrasonic transmitter / receivers 32. The circuit board 33 is provided with a connector for outputting measurement information to the outside. The connector is a member for electrically connecting the circuit board 33 to an external device of the gas meter 100, and has the function of stably transmitting measurement information signals via multiple contact points. A communication cable extending outside the gas meter 100 is connected to the connector. As a result, the measurement information generated by the circuit board 33 is transmitted to the communication cable via the connector and sent to the external device.

[0034] The two ultrasonic transmitter / receiver fixing devices 35 are members that fix the ultrasonic transmitter / receiver 32 held in the holding portion 59 of the ultrasonic transmitter / receiver holding portion 43, and have the function of restricting movement of the ultrasonic transmitter / receiver 32 relative to the ultrasonic transmitter / receiver holding portion 43. The ultrasonic transmitter / receiver fixing devices 35 sandwich the ultrasonic transmitter / receiver 32 between themselves and the holding portions 59. This allows the ultrasonic transmitter / receiver 32 to be stably fixed against vibrations and external forces. The ultrasonic transmitter / receiver fixing devices 35 are detachably attached to the ultrasonic transmitter / receiver holding portion 43.

[0035] The cover 74 covers the circuit board 33 and the two ultrasonic transmitter / receivers 32, and protects the circuit board 33 and the two ultrasonic transmitter / receivers 32 from moisture, etc. The cover 74 is detachably attached to the main body block 31 or the circuit board fixing portion 34.

[0036] <Connection joint> The connection fitting 15 is a tubular body that defines a connection flow path 81 through which the fluid to be measured flows. The upstream end of the connection flow path 81 is connected to the measurement flow path 54 and forms an inlet for the fluid to be measured. The downstream end of the connection flow path 81 communicates with the outlet 27 and forms an outlet for the fluid to be measured.

[0037] <Connection structure of measurement unit and connection joint> Fig. 4 is an enlarged cross-sectional view of a main part showing an example of the configuration related to the connection structure between the measurement unit 14 and the connection joint 15, and is a cross-sectional view on a plane extending along the flow direction DF and the short side direction DS. Fig. 5 is an enlarged cross-sectional view of a main part showing an example of the configuration related to the connection structure between the measurement unit 14 and the connection joint 15, and is a cross-sectional view on a plane passing through the fixed shaft 17 and extending along the longitudinal direction DL and the short side direction DS.

[0038] As shown in FIG. 3, the flow path forming portion 41 of the measurement unit 14 further has a measurement unit side connection portion 46 as a connection structure. The measurement unit side connection portion 46 is a portion that is connected to the connection joint 15. The measurement unit side connection portion 46 is located at the downstream end of the main body block 31 in the flow direction DF. The measurement unit side connection portion 46 is a frame-shaped portion that protrudes outward from the outer peripheral surface of the downstream end of the main body block 31 in the flow direction DF, and is located so as to surround the outlet of the measurement flow path 54. The measurement unit side connection portion 46 includes a recess 63 and two measurement unit side through holes 62.

[0039] The recess 63 is a portion recessed toward the upstream side from the surface facing the downstream side of the flow direction DF of the measurement unit side connection part 46, and is an annular groove surrounding the outlet of the measurement flow path 54. The bottom surface of the recess 63 forms the measurement unit side connection surface 65. The measurement unit side connection surface 65 is a surface located on a plane intersecting the flow direction DF of the fluid to be measured, i.e., on a plane extending along the longitudinal direction DL and the lateral direction DS. The measurement unit side connection surface 65 faces downstream of the flow direction DF. The recess 63 is a portion into which a flat seal member 16, which will be described later, is fitted.

[0040] The two measurement unit side through holes 62 are through holes through which the fixed shafts 17 are inserted. The measurement unit side through holes 62 are located on the upstream side of the recess 63 in the flow direction DF. The measurement unit side through holes 62 extend, for example, in a direction perpendicular to the flow direction DF. More specifically, the measurement unit side through holes 62 extend in the short direction DS.

[0041] 2, the connection joint 15 further includes, as a connection structure, a connection joint side connecting portion 77 connected to the measurement unit 14. The connection joint side connecting portion 77 includes a receiving wall portion 82 and a peripheral wall portion 83.

[0042] The receiving wall portion 82 has a rectangular cross section relative to the flow direction DF, and includes a connection joint side connecting surface 87. As shown in Fig. 4, the connection joint side connecting surface 87 faces the upstream side of the flow direction DF, is positioned opposite the measurement unit side connecting surface 65, and surrounds the inlet of the connection flow path 81.

[0043] 2 and 4, the peripheral wall portion 83 is a portion that extends from the periphery of the receiving wall portion 82 toward the upstream side of the flow direction DF, and has a rectangular cross section. When the measurement unit side connection portion 46 is fitted into the peripheral wall portion 83, the peripheral wall portion 83 surrounds the measurement unit side connection portion 46. This allows the peripheral wall portion 83 to restrict positional deviation of the measurement unit side connection portion 46 in a direction intersecting with the flow direction DF.

[0044] As shown in FIGS. 2 and 5 , the peripheral wall portion 83 includes two pairs of connection joint side through holes 89 aligned in the longitudinal direction DL. In the longitudinal direction DL, the measurement flow path 54 is located between the two pairs of connection joint side through holes 89. The connection joint side through hole 89 is a through hole through which a fixed shaft 17, which will be described later, is inserted. In this embodiment, each pair of connection joint side through holes 89 is positioned coaxially. Furthermore, when the measurement unit side connection portion 46 is fitted into the peripheral wall portion 83, one of the two measurement unit side through holes 62 is positioned coaxially with one of the two pairs of connection joint side through holes 89, and the other of the two measurement unit side through holes 62 can be positioned coaxially with the other of the two pairs of connection joint side through holes 89. Furthermore, one of the pair of connection joint side through holes 89 has a large diameter portion 90 formed therein. The large diameter portion 90 is located at the outer end of the connection joint side through hole 89.

[0045] 3, the maximum dimension ML1 in the longitudinal direction DL of the end portion on the outlet side of the measurement flow path 54 of the flow path forming portion 41, i.e., the measurement unit side connection portion 46, is the same as the maximum dimension ML2 in the longitudinal direction DL of the end portion on the inlet side of the measurement flow path 54 of the measurement unit 14, i.e., the funnel portion 45. Furthermore, the maximum dimension MS1 ​​in the lateral direction DS of the measurement unit side connection portion 46 is the same as the maximum dimension MS2 in the lateral direction DS of the funnel portion 45. This makes it possible to prevent the funnel portion 45 and the measurement unit side connection portion 46, which extend outward beyond the wall portion 55 when viewed from the flow direction DF, from interfering with the surrounding environment.

[0046] The gas meter 100 further includes, as a connection structure, a flat seal member 16, a fixture including a fixed shaft 17, and two pins 94.

[0047] 4, the flat sealing member 16 is a member that is positioned between the measurement unit side connection surface 65 and the connection joint side connection surface 87 so as to fill the gap between the measurement unit 14 and the connection joint 15. The material of the flat sealing member 16 is an elastic body such as rubber.

[0048] As shown in FIG. 2, the flat seal member 16 has a thin, flat plate shape, with both surfaces being flat. An opening is formed in the center of the flat seal member 16. As shown in FIG. 4, the flat seal member 16 faces the space connecting the measurement flow path 54 and the connection flow path 81. The flat seal member 16 is fitted into and held in a recess 63 of the measurement unit side connection part 46. This prevents the flat seal member 16 from shifting position or falling off. The measurement unit side connection surface 65 functions as a seat surface that supports the flat seal member 16. The depth dimension of the recess 63 is smaller than the thickness dimension of the flat seal member 16. This allows the flat seal member 16 to protrude from the recess 63 (see FIG. 8).

[0049] The fixed shaft 17 is a member that is inserted into the measurement unit side through-hole 62 and the connection joint side through-hole 89 to connect the measurement unit 14 and the connection joint 15 and fix the measurement unit 14 to the connection joint 15. The fixed shaft 17 includes two pin insertion holes 93 and protrusions 95 formed on both ends.

[0050] The two pin insertion holes 93 are located outside the measurement unit side through hole 62 and the connection joint side through hole 89 when the fixed shaft 17 is inserted through the measurement unit side through hole 62 and the connection joint side through hole 89. Pins 94, which are snap pins, are attached to the two pin insertion holes 93. This positions the fixed shaft 17 and holds it so that it does not slip out of the measurement unit side through hole 62 and the connection joint side through hole 89.

[0051] The protrusion 95 is a protrusion that protrudes in the radial direction of the fixed shaft 17. The protrusion 95 is one end of the fixed shaft 17 and is located inside one of the pin insertion holes 93. The protrusion 95 fits into the large diameter hole portion 90.

[0052] The distance between the measurement unit side connection surface 65 and the connection joint side connection surface 87 is set to be smaller than the thickness dimension of the flat seal member 16 when the measurement unit side through hole 62 and the connection joint side through hole 89 are positioned coaxially. Therefore, when the fixed shaft 17 is inserted through the measurement unit side through hole 62 and the connection joint side through hole 89, the flat seal member 16 is compressed and deformed in the flow direction DF. This closes the gap between the measurement unit 14 and the connection joint 15, sealing the space between the measurement flow path 54 and the connection flow path 81 and suppressing leakage of the measured fluid. In particular, the gas meter 100 suitable for industrial applications has a large cross-sectional area of ​​the measurement flow path 54. Therefore, even if the main body block 31 is bent, the space between the measurement flow path 54 and the connection flow path 81 can be effectively sealed, effectively suppressing leakage of the measured fluid. The fixed shaft 17 maintains the state in which the measuring unit side connecting surface 65 and the connecting joint side connecting surface 87 are pressed together with a predetermined surface pressure via the flat seal member 16 .

[0053] The flat seal member 16 is compressed with a predetermined uniform surface pressure in the flow direction DF by two flat surfaces, the measurement unit side connection surface 65 and the connection joint side connection surface 87. This keeps the flat seal member 16 in an appropriately compressed state, suppresses leakage of the fluid to be measured, and improves measurement accuracy.

[0054] Furthermore, in a state in which the fixed shaft 17 is inserted through the measurement unit side through hole 62 and the connection joint side through hole 89, the measurement unit side through hole 62 and the connection joint side through hole 89 extend in a direction perpendicular to the direction of the surface pressure acting on the measurement unit side connecting surface 65 and the connection joint side connecting surface 87, i.e., along a plane including the longitudinal direction DL and the lateral direction DS. The fixed shaft 17 extends in a direction perpendicular to the direction of the surface pressure, and receives a compressive load from the surfaces forming the measurement unit side through hole 62 and the connection joint side through hole 89, and resists the surface pressure. This makes it possible to effectively maintain a state in which the measurement unit side connecting surface 65 and the connection joint side connecting surface 87 are pressed together at a predetermined surface pressure via the flat seal member 16.

[0055] When connecting the measurement unit 14 to the connection joint 15, the flat seal member 16 is fitted into the recess 63 of the measurement unit 14. Then, the measurement unit side connection portion 46 is inserted into the peripheral wall portion 83 of the connection joint side connection portion 77 and pressed against the connection joint side connection surface 87, so that the two pairs of connection joint side through holes 89 and the two measurement unit side through holes 62 are coaxially positioned. Then, two fixed shafts 17 are inserted into the two pairs of connection joint side through holes 89 and the two measurement unit side through holes 62, and the protrusions 95 of the fixed shafts 17 are fitted into the large diameter hole portions 90 of the connection joint 15. This allows stable positioning of the fixed shafts 17. Then, a pin 94 is inserted into the pin insertion hole 93 of the fixed shaft 17 and fastened.

[0056] In this way, the measurement unit 14 and the connection joint 15 can be fixed by inserting the fixing shaft 17 into the measurement unit side through hole 62 and the connection joint side through hole 89, which simplifies the configuration of the fixing structure between the measurement unit 14 and the connection joint 15, which is advantageous for manufacturing and also reduces manufacturing costs.

[0057] (Embodiment 2) The following description of embodiment 2 will focus on the differences from embodiment 1. The basic configuration of embodiment 2 is similar to the configuration of embodiment 1, with differences being the number of measurement units provided in the gas meter, the presence or absence of a connecting structure for connecting the measurement units to each other, and the configuration of the connection joint.

[0058] Fig. 6 is a perspective view showing an example of the configuration of a first measurement unit 214A, a second measurement unit 214B, and a connection joint 215 of a gas meter according to embodiment 2. As shown in Fig. 6, the gas meter according to embodiment 2 includes two measurement units, that is, a first measurement unit 214A and a second measurement unit 214B. The gas meter also includes a connection joint 215 to which the two measurement units are connected.

[0059] FIG. 7 is a perspective view showing a configuration example of a connection joint 215 of a gas meter according to the second embodiment. As shown in FIG. 7, the connection joint 215 includes a connection joint side connecting portion 277 connected to a first measurement unit 214A and a second measurement unit 214B. The connection joint side connecting portion 277 has two openings, a first opening 216A and a second opening 216B, which are separated from each other at the upstream end. The first opening 216A is connected to the measurement flow path 54 of the first measurement unit 214A and forms an inlet for the fluid to be measured flowing out from the first measurement unit 214A. The second opening 216B is connected to the measurement flow path 54 of the second measurement unit 214B and forms an inlet for the fluid to be measured flowing out from the second measurement unit 214B. The connection joint side connecting portion 277 includes a receiving wall portion 282 and a peripheral wall portion 283.

[0060] The receiving wall portion 282 includes a first connection joint side connection surface 287A and a second connection joint side connection surface 287B. The first connection joint side connection surface 287A is located opposite the measurement unit side connection surface 65 (see FIG. 3) of the first measurement unit 214A. The second connection joint side connection surface 287B is located opposite the measurement unit side connection surface 65 of the second measurement unit 214B. In this way, the first connection joint side connection surface 287A and the second connection joint side connection surface 287B are formed corresponding to the measurement unit side connection surface 65 of the first measurement unit 214A and the measurement unit side connection surface 65 of the second measurement unit 214B, respectively. The first connection joint side connection surface 287A and the second connection joint side connection surface 287B are located on the same plane.

[0061] The peripheral wall portion 283 is a portion that extends from the periphery of the receiving wall portion 282 toward the upstream side of the flow direction DF, and has a rectangular cross section. When the measurement unit side connectors 46 of the first measurement unit 214A and the second measurement unit 214B are fitted into the peripheral wall portion 283, the peripheral wall portion 283 surrounds the measurement unit side connectors 46 of the first measurement unit 214A and the second measurement unit 214B, and has the function of restricting positional deviation of the first measurement unit 214A and the second measurement unit 214B in a direction intersecting with the flow direction DF.

[0062] The peripheral wall portion 283 includes two pairs of connection joint side through holes 89. Furthermore, in a state in which the measurement unit side connecting portions 46 of the first measurement unit 214A and the second measurement unit 214B are fitted into the peripheral wall portion 283, one of the two measurement unit side through holes 62 of the first measurement unit 214A, one of the two measurement unit side through holes 62 of the second measurement unit 214B, and one of the two pairs of connection joint side through holes 89 are positioned coaxially, and the other of the two measurement unit side through holes 62 of the first measurement unit 214A, the other of the two measurement unit side through holes 62 of the second measurement unit 214B, and the other of the two pairs of connection joint side through holes 89 are positioned coaxially.

[0063] As shown in FIG. 6, the first measurement unit 214A and the second measurement unit 214B are connected to the connection joint side connection part 277 with their second longitudinal wall parts 52 facing each other and their first longitudinal wall parts 51 facing outward.

[0064] A fixed shaft 217 serving as a fixture for fixing the first measurement unit 214A and the second measurement unit 214B to the connection joint 215 is inserted through the measurement unit-side through-hole 62 of the first measurement unit 214A, the measurement unit-side through-hole 62 of the second measurement unit 214B, and the connection joint-side through-hole 89, which are positioned coaxially. This allows the first measurement unit 214A and the second measurement unit 214B to be positioned so that the relative positional relationship between the first measurement unit 214A and the second measurement unit 214B is accurately maintained. The fixed shaft 217, like the fixed shaft 17, has a pin insertion hole into which a pin is fastened.

[0065] The gas meter according to the second embodiment further includes a connection structure that connects the first measurement unit 214A and the second measurement unit 214B to each other.

[0066] FIG. 8 is a perspective view showing a configuration example of the first measurement unit 214A. As shown in FIGS. 6 and 8, the first measurement unit 214A has two first measurement unit connectors 248A as a connection structure in addition to the configuration described in the first embodiment. The first measurement unit connector 248A is a cylindrical portion extending parallel to the measurement unit side through-hole 62 and has a first measurement unit side through-hole 273A. The first measurement unit connector 248A is provided in an upstream portion of the main body block 31 in the flow direction DF. More specifically, the two first measurement unit connectors 248A are provided on the outer wall surfaces of the two side wall portions 53. The first measurement unit connector 248A has a first engagement notch 274A formed at an end of the first measurement unit connector 248A on the second longitudinal wall portion 52 side. The first engagement notch 274A is a recess formed by partially cutting out and recessing the end face.

[0067] The second measurement unit 214B is configured similarly to the first measurement unit 214A, and has a second measurement unit connecting portion 248B having a second measurement unit side through hole 273B and a second engagement notch 274B. When the first measurement unit 214A and the second measurement unit 214B are connected to the connection joint side connecting portion 277, one first engagement notch 274A of the first measurement unit 214A and one second engagement notch 274B of the second measurement unit 214B are arranged to be aligned in a straight line in the short side direction DS, and the other first engagement notch 274A of the first measurement unit 214A and the other second engagement notch 274B of the second measurement unit 214B are arranged to be aligned in a straight line in the short side direction DS.

[0068] Furthermore, as a connection structure, the gas meter further includes a connection tool including two connection shafts 296 .

[0069] The connecting shaft 296 is inserted through the first measurement unit side through-hole 273A and the second measurement unit side through-hole 273B to connect the first measurement unit 214A and the second measurement unit 214B. The connecting shaft 296 includes an engagement protrusion 297 and two pin insertion holes 298.

[0070] The engagement protrusion 297 is located in the axial center of the connecting shaft 296 and protrudes radially outward from the outer circumferential surface of the connecting shaft 296. The engagement protrusion 297 engages with the first engagement notch 274A and the second engagement notch 274B, thereby preventing the connecting shaft 296 from rotating.

[0071] The two pin insertion holes 298 are located at both ends of the connecting shaft 296. Pins 299, which are snap pins, are attached to the two pin insertion holes 298. This prevents the connecting shaft 296 from coming out of the first measurement unit side through-hole 273A and the second measurement unit side through-hole 273B. This prevents the first measurement unit 214A and the second measurement unit 214B from being disconnected.

[0072] When connecting the first measurement unit 214A and the second measurement unit 214B to the connection joint 215, first, one end of each of the two connecting shafts 296 is inserted into the two first measurement unit side through holes 273A of the first measurement unit 214A, and the other end of each of the two connecting shafts 296 is inserted into the two second measurement unit side through holes 273B of the second measurement unit 214B. Then, pins 299 are inserted into the pin insertion holes 298 provided at both ends of the connecting shafts 296, respectively, and fastened.

[0073] Then, the flat seal members 16 are fitted into the recesses 63 of the first measurement unit 214A and the second measurement unit 214B. Then, the measurement unit side connecting portions 46 of the first measurement unit 214A and the second measurement unit 214B are inserted into the peripheral wall portion 283 of the connection joint side connecting portion 277 and pressed against the first connection joint side connecting surface 287A and the second connection joint side connecting surface 287B, so that the two pairs of connection joint side through holes 89, the two measurement unit side through holes 62 of the first measurement unit 214A, and the two measurement unit side through holes 62 of the second measurement unit 214B are coaxially positioned. Then, the two fixed shafts 217 are inserted into the two measurement unit side through holes 62 of the first measurement unit 214A and the two measurement unit side through holes 62 of the second measurement unit 214B, respectively. Then, pins are inserted into the pin insertion holes of the fixed shafts 217 and fastened.

[0074] As described above, the gas meter of this embodiment includes a plurality of measurement units, and can be made into a gas meter that can handle a higher flow rate.

[0075] Furthermore, the first connection joint side connection surface 287A and the second connection joint side connection surface 287B are formed corresponding to the measurement unit side connection surfaces 65 of the first measurement unit 214A and the second measurement unit 214B, respectively, and are located on the same plane. This makes it possible to make the flow rates of the fluid to be measured flowing into the first measurement unit 214A and the second measurement unit 214B uniform.

[0076] Furthermore, similarly to the above-described first embodiment, the maximum dimension ML1 in the longitudinal direction DL of the measurement unit side connection portion 46 in the second embodiment is the same as the maximum dimension ML2 in the longitudinal direction DL of the funnel portion 45. Furthermore, the maximum dimension MS1 ​​in the lateral direction DS of the measurement unit side connection portion 46 is the same as the maximum dimension MS2 in the lateral direction DS of the funnel portion 45. This makes it possible to prevent the funnel portion 45 and the measurement unit side connection portion 46, which extend outward beyond the wall portion 55 of one measurement unit 214A when viewed from the flow direction DF, from interfering with the other measurement unit 214B, thereby making it possible to make the gas meter compact.

[0077] (Embodiment 3) The following description of embodiment 3 will focus on the differences from embodiment 2. Fig. 9 is a perspective view showing an example of the configuration of a connection joint of a gas meter according to embodiment 3. The basic configuration of embodiment 3 is similar to that of embodiment 2, with differences being in the number of measurement units provided in the gas meter and the configuration of the connection joint.

[0078] In the second embodiment, the gas meter is provided with two measurement units, but in the present embodiment, the gas meter is provided with four measurement units.

[0079] 9, in the present embodiment, the connection joint 315 has four connection joint side connection surfaces 387, and four measurement units are connected to the connection joint. The four connection joint side connection surfaces 387 may be configured such that the first connection joint side connection surfaces 287A and the second connection joint side connection surfaces 287B in the second embodiment are arranged in two rows in the longitudinal direction DL.

[0080] (Fourth embodiment) A measurement unit according to embodiment 4 is shown in Figs. 10 to 12. Fig. 10 shows an example of the configuration of a measurement unit of a gas meter, and is, from top to bottom, a front view, a rear view, a plan view, and a bottom view. Fig. 11 shows, from top to bottom, a left side view, a right side view, and a perspective view 1. Fig. 12 shows, from top to bottom, a perspective view 2 and a reference perspective view showing the state of use.

[0081] (Embodiment 5) A measurement unit according to the fifth embodiment is shown in Figs. 13 to 16. Fig. 13 is a diagram showing an example of the configuration of a measurement unit of a gas meter according to the fifth embodiment, and is, from top to bottom, a front view, a rear view, a plan view, and a bottom view. Fig. 14 is, from top to bottom, a left side view, a right side view, and a perspective view 1. Fig. 15 is, from top to bottom, a perspective view 2 and a reference perspective view 1 showing the state of use. Fig. 16 is a reference perspective view 2 showing the state of use.

[0082] From the above description, many modifications and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present invention.

[0083] (Other embodiments) (Technology 1) The gas meter of Technology 1 comprises a measurement box having an internal space, a meter inlet portion having an inlet through which the fluid to be measured flows into the meter box; a meter outlet portion having an outlet through which the fluid to be measured that has flowed into the meter inlet portion flows out from the meter box; a measuring unit that is housed in the measurement box and has a flow path forming portion that defines a measurement flow path through which the fluid to be measured flows, and a measurement unit side connection surface that surrounds an outlet of the measurement flow path and is located on a plane that intersects with the flow direction of the fluid to be measured, and that measures the flow rate of the fluid to be measured flowing through the measurement flow path; a connection joint that defines a connection flow path that communicates with the outlet and through which the fluid to be measured flows, the connection joint having a connection joint side connection surface that faces the measurement unit side connection surface and surrounds an inlet of the connection flow path; a flat seal member positioned between the measurement unit side connection surface and the connection joint side connection surface and facing a space connecting the measurement flow path and the connection flow path; a fixing device that fixes the measuring unit to the connection joint and maintains the measuring unit side connection surface and the connection joint side connection surface in a pressure-welded state at a predetermined surface pressure via the flat seal member.

[0084] (Technology 2) The gas meter of Technology 2 is the gas meter described in Technology 1, wherein the fixing device includes a fixed shaft, the measurement unit has a measurement unit-side through-hole through which the fixed shaft is inserted, and the connection joint has a connection joint-side through-hole through which the fixed shaft is inserted.

[0085] (Technology 3) A gas meter according to a third aspect of the present invention is the gas meter according to the second aspect, wherein the fixed shaft, the measurement unit side through-hole, and the connection joint side through-hole extend in a direction perpendicular to the direction of the surface pressure.

[0086] (Technology 4) The gas meter of Technology 4 is a gas meter according to any one of Technologies 1 to 3, which includes a plurality of the measurement units, and the connection joint has a plurality of the connection joint side connection surfaces formed corresponding to the measurement unit side connection surfaces of each of the measurement units and positioned on the same plane as each other.

[0087] (Technology 5) The gas meter of Technology 5 is a gas meter described in any one of Technologies 1 to 4, wherein the fixing device is a fixed shaft, the measuring units are a first measuring unit and a second measuring unit, the first measuring unit has a measuring unit side through hole through which the fixed shaft is inserted, and the second measuring unit has a second through hole through which the fixed shaft is inserted and which is coaxial with the measuring unit side through hole.

[0088] (Technology 6) A gas meter of Technology 6 is a gas meter described in any one of Technologies 1 to 5, wherein the maximum longitudinal dimension intersecting the flow direction of the outlet side end of the measurement flow path of the flow path forming part is the same as the maximum longitudinal dimension of the inlet side end of the measurement flow path of the flow path forming part, and the maximum lateral dimension intersecting the flow direction and the longitudinal direction of the outlet side end of the measurement flow path of the flow path forming part is the same as the maximum lateral dimension of the inlet side end of the measurement flow path of the flow path forming part. [Explanation of symbols]

[0089] DF flow direction DL Longitudinal DS Short direction 11 Measurement box 12 Meter inlet 13 Meter outlet 14 Measurement Unit 15 Connection joints 16 Flat seal member 17 Fixed axis 19 Shut-off valve 24 Interior Space 26 Inlet 27 Outlet 32 Ultrasonic Transmitter / Receiver 41 Flow path forming section 46 Measurement unit side connection part 54 Measurement flow path 65 Measurement unit side connection surface 77 Connection joint side connection part 81 Connecting channel 87 Connection joint side connection surface 100 Gas Meter

Claims

1. a measurement box having an internal space; a meter inlet portion having an inlet through which the fluid to be measured flows into the meter box; a meter outlet portion having an outlet through which the fluid to be measured that has flowed into the meter inlet portion flows out from the meter box; a measuring unit that is housed in the measurement box and has a flow path forming portion that defines a measurement flow path through which the fluid to be measured flows, and a measurement unit side connection surface that surrounds an outlet of the measurement flow path and is located on a plane that intersects with the flow direction of the fluid to be measured, and that measures the flow rate of the fluid to be measured flowing through the measurement flow path; a connection joint that defines a connection flow path that communicates with the outlet and through which the fluid to be measured flows, the connection joint having a connection joint side connection surface that faces the measurement unit side connection surface and surrounds an inlet of the connection flow path; a flat seal member positioned between the measurement unit side connection surface and the connection joint side connection surface and facing a space connecting the measurement flow path and the connection flow path; a fixing device that fixes the measuring unit to the connection joint and maintains the measuring unit side connection surface and the connection joint side connection surface in a pressure-welded state at a predetermined surface pressure via the flat seal member.

2. the fixture includes a fixed shaft; the measurement unit has a measurement unit-side through-hole through which the fixed shaft is inserted, The gas meter according to claim 1 , wherein the connection joint has a connection joint-side through-hole through which the fixed shaft is inserted.

3. The gas meter according to claim 2 , wherein the fixed shaft, the measurement unit side through-hole, and the connection joint side through-hole extend in a direction perpendicular to the direction of the surface pressure.

4. A plurality of the measurement units are provided, The gas meter according to claim 1 , wherein the connection joint has a plurality of connection joint-side connection surfaces formed corresponding to the measurement unit-side connection surfaces of the measurement units and positioned on the same plane as one another.

5. the fixture is a fixed shaft, the measurement units are a first measurement unit and a second measurement unit, the first measurement unit has a measurement unit-side through-hole through which the fixed shaft is inserted, The gas meter according to claim 1 , wherein the second measurement unit has a second through-hole through which the fixed shaft is inserted and which is coaxial with the measurement unit side through-hole.

6. a maximum dimension in a longitudinal direction intersecting the flow direction of the outlet side end of the measurement flow path of the flow path forming portion is the same as a maximum dimension in the longitudinal direction of the inlet side end of the measurement flow path of the flow path forming portion, 3. The gas meter according to claim 1, wherein the maximum dimension in a short direction intersecting the flow direction and the longitudinal direction of the outlet side end of the measurement flow path of the flow path forming portion is the same as the maximum dimension in the short direction of the inlet side end of the measurement flow path of the flow path forming portion.

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