JP7649701B2 - Gas meter - Google Patents

Description

This disclosure relates to a gas meter having a shutoff valve that cuts off the supply of gas into the meter case in the event of an abnormality.

A known example of this type of gas meter is one in which the valve seat components of the shutoff valve and the rectifier are assembled into a meter case (see, for example, Patent Document 1).

JP 2010-008116 A (paragraphs [0027], [0028] and FIG. 2)

Compared to conventional gas meters, there is a demand to reduce the number of parts assembled into the meter case.

The invention of claim 1, which has been made to achieve the above object, is a gas meter that includes a meter case having an inflow chamber adjacent to a measurement chamber for measuring the flow rate of gas, in which gas flowing into the inflow chamber from a second direction perpendicular to a first direction in which the measurement chamber and the inflow chamber are aligned flows into the measurement chamber through a through hole penetrating a partition wall between the inflow chamber and the measurement chamber, a rectifier that rectifies the gas flowing into the measurement chamber from the inflow chamber, and a shutoff valve having a valve body that closes the through hole from the inflow chamber side in the event of an abnormality, the rectifier is a gas meter that includes a ring portion that is fitted and fixed into the through hole, and a valve seat that is formed in the ring portion and abuts against the valve body in the event of an abnormality.

The invention of claim 2 is a gas meter according to claim 1, in which the flow straightener is provided with a partial blocking wall that blocks a part of the inside of the ring portion and a partial opening on the inside of the ring portion that is not blocked by the partial blocking wall, the measurement chamber contains a measurement tube that has a tubular structure, through which all of the gas passing through the measurement chamber passes and whose end opening faces the partial blocking wall, and the flow rate of gas is measured based on the flow velocity of the gas passing through the measurement tube.

The invention of claim 3 is the gas meter according to claim 2, in which the partial blocking wall is disposed at the end of the ring portion on the side of the measurement room, and the side surface of the partition wall facing the measurement room and the main plane of the partial blocking wall facing the measurement room are disposed flush with each other.

In the invention of claim 4, an edge portion of the partial closing wall on the partial opening side extends linearly,
4. The gas meter according to claim 2, wherein the end opening of the measuring pipe is rectangular, and one side of the rectangle is arranged parallel to an edge of the partial closing wall on the partial opening side.

The invention of claim 5 is a gas meter according to any one of claims 2 to 4, in which the partial blocking wall is disposed on the upstream side of the inlet chamber in the through hole.

The invention of claim 6 is a gas meter according to any one of claims 1 to 5, in which the axial length of the rectifier is smaller than the wall thickness of the partition wall.

The invention of claim 7 is a gas meter according to any one of claims 1 to 6, in which the valve body has a disk-shaped packing overlaid on the surface facing the through hole, and the valve seat is annular, protruding from the ring portion toward the inlet chamber, and is structured to bite into the packing.

In the gas meter of the present disclosure, an inflow chamber and a measurement chamber adjacent to each other in a first direction are provided in a meter case, and gas flowing into the inflow chamber from a second direction perpendicular to the first direction flows into the measurement chamber through a through hole provided in a partition wall between the inflow chamber and the measurement chamber, and in the event of an abnormality, the valve body of the shutoff valve closes the through hole from the inflow chamber side to block the flow of gas into the measurement chamber. A rectifier for rectifying the gas flowing from the inflow chamber into the measurement chamber is provided in a ring portion that is fitted and fixed into the through hole. Furthermore, the ring portion is also provided with a valve seat against which the valve body of the shutoff valve abuts in the event of an abnormality. In other words, in the gas meter of the present disclosure, the rectifier and the valve seat are integrally formed, so that the number of parts to be assembled to the meter case can be reduced.

In the gas meter of claim 2, the rectifier has a partial blocking wall that blocks the inside of the ring portion and a partial opening that is not blocked. The measurement chamber contains a measurement tube through which all of the gas passing through the measurement chamber passes, and the partial blocking wall faces the end opening of the measurement tube. As a result, even if the gas that has passed through the partial opening of the rectifier is in a turbulent state, it can be rectified so that the gas flowing into the measurement tube is in a laminar flow state by flowing in the second direction along the surface of the partial blocking wall and then changing direction toward the end opening side (first direction) of the measurement tube.

In addition, if the partial blocking wall is disposed on the upstream side of the inflow chamber in the through hole (invention of claim 5), most of the gas flowing into the inflow chamber from the second direction is received by the partial blocking wall. As a result, the gas first flows in the second direction along the surface of the partial blocking wall, then changes direction and passes through the partial opening, and then flows in the second direction along the surface of the partial blocking wall before changing direction toward the end opening of the measurement pipe, so that the gas flowing into the measurement pipe can be further straightened.

Furthermore, by arranging the partial blocking wall at the end of the ring section on the measurement room side and arranging the main plane of the partial blocking wall on the measurement room side flush with the inner surface of the partition wall on the measurement room side (invention of claim 3), it is possible to suppress an increase in pressure loss in front of the end opening of the measurement tube. Also, if the end opening of the measurement tube is rectangular, by arranging one side of the rectangle parallel to the edge of the partial opening side of the partial blocking wall (invention of claim 4), it is possible to make the gas that flows along the surface of the partial blocking wall flow uniformly into the measurement tube.

Moreover, as in the gas meter of claim 6, if the axial length of the rectifier is configured to be smaller than the thickness of the partition wall, the gas flowing into the measurement chamber can be rectified with a compact structure that fits inside the through hole.

Also, as in the gas meter of claim 7, the valve seat may be configured to protrude from the ring portion in an annular shape toward the inlet chamber, and to bite into a disk-shaped packing provided on the surface of the valve body of the shutoff valve facing the through hole, thereby blocking the through hole.

FIG. 1 is a perspective view of a gas meter according to an embodiment of the present invention; Exploded perspective view of a gas meter Front cross-sectional view of a gas meter A perspective view of the gas meter with the front cover and front lid removed (A) A perspective view of the flow rectifier as seen from the measurement room, and (B) a perspective view as seen from the inlet room. 1 is a perspective view of a valve body of a shutoff valve; Enlarged cross-sectional view of a gas meter 1A is a perspective view of a flow rectifier according to another embodiment, and FIG. 1B is a perspective view of the flow rectifier according to another embodiment, as seen from a measurement chamber. FIG. 13 is an enlarged front cross-sectional view of a gas meter according to another embodiment. FIG. 13 is an enlarged front cross-sectional view of a gas meter according to another embodiment.

The gas meter 10A of this embodiment will be described below with reference to Figures 1 to 7. The gas meter 10A of this embodiment is a so-called ultrasonic flowmeter that uses ultrasonic waves to measure the flow rate of fuel gas, and is equipped with a meter case 11 connected midway through a gas pipe 99, which houses a shutoff valve 20 (see Figure 2), a measuring pipe 50 (see Figure 3), a rectifier 70 (see Figure 3), etc.

The meter case 11 is, for example, an aluminum die-cast product, and has a duct portion 12 that is a substantially rectangular parallelepiped extending in the horizontal direction. Hereinafter, the first horizontal direction in which the duct portion 12 extends is referred to as the "first direction H1," and the second horizontal direction perpendicular to it is referred to as the "front-rear direction H2." In addition, the side of the front-rear direction H2 that has the front flange 16 described below is referred to as the "front side," etc., and the opposite side is referred to as the "rear side," etc. The up-down direction corresponds to the "second direction" in the claims.

As shown in FIG. 2, the hood section 13 is provided with a left side opening 10K on the left side of the duct section 12 when viewed from the front (hereinafter, simply referred to as the "left side" and the opposite side simply referred to as the "right side"). The hood section 13 has a chamfered inclined wall 35 at each of its four corners. Furthermore, a rectangular frame-shaped protruding wall 36 protrudes from the edge of the left side opening 10K. An annular O-ring groove 36A is formed in the end face of the frame-shaped protruding wall 36, and screw holes are formed in the four corners outside the O-ring groove 36A. Then, with an O-ring (not shown) housed in the O-ring groove 36A, the left side cover 15 is fitted to the frame-shaped protruding wall 36 and screwed in place. This seals the left side opening 10K of the hood section 13.

The space between the hood section 13 and the duct section 12 is partitioned by the valve mounting wall 14. As shown in FIG. 3, the inside of the duct section 12 is partitioned into an inflow chamber 30, a measurement chamber 31, an intermediate chamber 32, and an outflow chamber 33 by first to third partition walls 25, 26, and 27, which are arranged in order from the valve mounting wall 14 side in the first direction H1. The first partition wall 25 corresponds to the "partition wall" in the claims.

As shown in FIG. 3, the duct section 12 is provided on the right side as viewed from the front with a right side opening 33K through which the outflow chamber 33 is opened, and a rectangular frame-shaped protruding wall 37 protrudes from the opening edge of the right side opening 33K. Then, with an O-ring (not shown) housed in the annular O-ring groove 37A formed in the frame-shaped protruding wall 37, the right side cover 19 is fitted to the frame-shaped protruding wall 37 and screwed in place, sealing the right side opening 33K (see FIG. 4).

A pair of connecting pipes 23, 24 protrude from both the left and right ends of the upper surface of the duct section 12 and communicate with the inlet chamber 30 and the outlet chamber 33. A gas pipe 99 (see FIG. 2) on the fuel gas supply side is connected to one connecting pipe 23 that communicates with the inlet chamber 30, while a gas pipe 99 on the fuel gas user side is connected to the other connecting pipe 24 that communicates with the outlet chamber 33.

As shown in FIG. 3, a circular side through-hole 14A is formed in the valve mounting wall 14, and a circular through-hole 28 is formed in the first partition wall 25 at a position opposite the side through-hole 14A in the first direction H1 and concentric with the side through-hole 14A. A rectifier 70, which will be described later, is fitted into the through-hole 28. As shown in FIG. 2, the fixing flange 20F of the shutoff valve 20 is screwed to the opening edge of the side through-hole 14A on the hood section 13 side with a packing (not shown) sandwiched therebetween, and the valve body 21 of the shutoff valve 20 is accommodated in the inflow chamber 30, and the inside of the hood section 13 forms a valve accommodation chamber 13K in which the drive source 22 of the shutoff valve 20 and the fixing flange 20F are accommodated. The fitting structure between the through-hole 28 and the rectifier 70 will be described in detail later.

As shown in FIG. 4, the front of the meter case 11 is provided with a front flange 16. The outer edge of the front flange 16 forms a horizontally long rectangle, and the front flange 16 extends vertically from the duct section 12, with the left end in the first direction H1 being integrated with the hood section 13. The entire front of the front flange 16, except for the outer edge, is recessed in a stepped shape to form a recessed section 16A, and a front opening 17 is formed within the recessed section 16A, which opens the front of the measurement chamber 31, the intermediate chamber 32, and the outflow chamber 33.

The aforementioned measuring pipe 50 has a square tube shape, and a pair of frame-shaped seal members 60 are fitted to both ends of the pipe (see FIG. 4). Correspondingly, the second and third partition walls 26 and 27 are formed with rectangular cutouts 29 that open on the front opening 17 side. The pair of frame-shaped seal members 60 are fitted into the rectangular cutouts 29, and the measuring pipe 50 extends in the first direction H1 to connect the measuring chamber 31 and the outflow chamber 33. At this time, the end opening 50A, which is the inlet of the measuring pipe 50, faces the through hole 28 of the first partition wall 25 in the first direction H1 (see FIG. 3). Specifically, the end opening 50A is arranged to face the upper half of the opening of the through hole 28. In addition, the measuring pipe 50 contains a pair of ultrasonic elements (not shown), and a control circuit on the circuit board 98 (see FIG. 1) calculates the amount of gas used based on the propagation time it takes for an ultrasonic wave sent from one ultrasonic element to propagate through the fuel gas and be received by the other ultrasonic element.

As shown in FIG. 2, the front opening 17 is closed by a front cover 18, which is a rectangular plate that is slightly larger than the front opening 17, and has its outer periphery screwed to the meter case 11. At this time, a packing (not shown) is laid on the inner surface of the front cover 18, and the space between the measurement chamber 31 and the intermediate chamber 32, and the space between the intermediate chamber 32 and the outflow chamber 33 are partitioned in an airtight state.

A cable insertion hole 18A is formed in the portion of the front cover 18 facing the intermediate chamber 32, and a cable (not shown) of the ultrasonic element of the measuring pipe 50 is pulled out to the front side of the front cover 18 through the cable insertion hole 18A. Also, as shown in FIG. 4, a cable insertion hole 16B that communicates with the valve accommodation chamber 13K is provided at the upper left side of the recessed portion 16A, and a cable (not shown) of the shutoff valve 20 is pulled out to the front side of the recessed portion 16A through the cable insertion hole 16B. Also, a sensor mounting hole 16C that communicates with the inlet chamber 30 is formed in the recessed portion 16A below the cable insertion hole 16B, and a pressure sensor (not shown) is attached to cover the sensor mounting hole 16C.

A circuit board 98 is attached to the front side of the front cover 18 in a stacked manner in the recess 16A. A front cover 81 is then attached to cover the circuit board 98 (see FIG. 1). An ultrasonic element, a shutoff valve 20, and a pressure sensor are connected to the circuit board 98, and a battery (not shown) housed in the front cover 81 is connected to the circuit board 98 as a power source. Then, the flow rate of the fuel gas is measured by the control circuit implemented on the circuit board 98 using the ultrasonic element as described above.

Furthermore, power is supplied to the shutoff valve 20 via a switch on the circuit board 98, and the valve body 21 is normally separated from the through hole 28 (the state shown in FIG. 3). When the pressure sensor detects an abnormality in the gas pressure, power to the shutoff valve 20 is cut off, and the valve body 21 closes the through hole 28. A vibration detector is also mounted on the circuit board 98, and when the vibration detector detects vibrations above a reference value, power to the shutoff valve 20 is also cut off, and the through hole 28 is closed.

As described above, in this embodiment, the rectifier 70 is fitted into the through hole 28 that connects the inflow chamber 30 and the measurement chamber 31, and the flow of fuel gas flowing from the inflow chamber 30 to the measurement chamber 31 is made uniform (see FIG. 3). Specifically, the rectifier 70 is an aluminum or brass molded product, and as shown in FIGS. 5(A) and (B), has a structure including a ring portion 71, partial blocking walls 74 that are disposed at both axial ends of the ring portion 71, and an annular protrusion 75.

As shown in FIG. 7, the ring portion 71 is fitted and fixed to the inner surface of the through hole 28. Specifically, the ring portion 71 has a peripheral surface that is concentric with the through hole 28 and parallel to the first direction H1, and a first step surface 71D that expands in diameter in a stepped manner on the inflow chamber 30 side is formed in the axially middle part of the outer peripheral surface, and the inflow chamber 30 side of the first step surface 71D is a large outer diameter portion 72, and the measurement chamber 31 side of the first step surface 71D is a small outer diameter portion 73.

The partial blocking wall 74 is provided on the end surface of the ring portion 71 on the side of the small outer diameter portion 73. As shown in FIG. 5(A), the partial blocking wall 74 is substantially semicircular and blocks the upper half of the inner opening of the ring portion 71, and the lower half of the inner opening of the ring portion 71 is a partial opening 74K that is not blocked by the partial blocking wall 74. As shown in FIG. 7, the partial blocking wall 74 faces the entire end opening 50A of the measuring pipe 50 in the first direction H1, and the straight part of the lower edge of the partial blocking wall 74 is disposed below the end opening 50A of the measuring pipe 50. Also, the straight part of the lower edge of the partial blocking wall 74 is disposed parallel to the lower side of the end opening 50A of the measuring pipe 50. The thickness of the partial blocking wall 74 is substantially the same as the radial thickness of the small outer diameter portion 73 of the ring portion 71.

The annular protrusion 75 protrudes in the first direction H1 from the end face of the ring portion 71 on the side of the large outer diameter portion 72. As shown in FIG. 7, the annular protrusion 75 has a tapered surface 75T on the tip side of its outer circumferential surface that narrows toward the tip, and the tip surface is an arcuate surface 75C that is chamfered in an arc shape. The inner circumferential surface of the annular protrusion 75 is flush with the inner circumferential surface of the ring portion 71. The radial thickness of the annular protrusion 75 is slightly larger than the radial thickness of the small outer diameter portion 73 of the ring portion 71.

The annular protrusion 75 serves as a valve seat against which the valve body 21 abuts when the current to the shutoff valve 20 is cut off. Specifically, the valve body 21 is disk-shaped and concentric with the through hole 28, and as shown in FIG. 6, a protrusion 21T that is triangular in plan view is provided in the center of the side surface 21A that faces the through hole 28. A packing (not shown) made of rubber or the like is attached to the protrusion 21T, and the surface of the valve body 21 that faces the through hole 28 has a flat shape. The arc surface 75C of the annular protrusion 75 bites into the packing, sealing the gap between the valve body 21 and the annular protrusion 75 and closing the through hole 28.

Here, as shown in FIG. 7, the inner surface of the through hole 28 into which the ring portion 71 of the rectifier 70 is fitted is formed with a second step surface 28D that expands in diameter in a stepped manner on the inflow chamber 30 side, and the first inner surface 28A is formed on the inflow chamber 30 side from the second step surface 28D, and the second inner surface 28B is formed on the measurement chamber 31 side from the second step surface 25D, which has a smaller diameter than the first inner surface 28A. The second inner surface 28B has a circumferential surface parallel to the first direction H1 and is approximately the same diameter as the outer diameter of the small outer diameter portion 73 of the ring portion 71, while the first inner surface 28A is a tapered surface that gradually expands in diameter as it moves away from the measurement chamber 31. The inner diameter of the end of the first inner surface 28A that is away from the measurement chamber 31 is approximately the same diameter as the outer diameter of the large outer diameter portion 72 of the ring portion 71. The outer diameter of the valve body 21 is smaller than the inner diameter of the first inner surface 28A of the through hole 28.

In this embodiment, as shown in FIG. 7, the inner surface of the inflow chamber 30 is formed in a cylindrical shape that opens at both ends of the side through hole 14A and the through hole 28. In other words, the inner surface of the inflow chamber 30 is flush with the first inner surface 28A of the through hole 28 and the inner surface of the side through hole 14A. As described above, the first inner surface 28A of the through hole 28 is a tapered surface that expands in diameter toward the side through hole 14A, and the inner surface of the side through hole 14A is a tapered surface that continues with the first inner surface 28A of the through hole 28. In addition, an inner surface opening 23A that communicates with one of the connecting pipes 23 is formed on the inner surface of the inflow chamber 30.

The rectifier 70 is assembled to the meter case 11 before the shutoff valve 20 and fitted into the through hole 28. Specifically, the rectifier 70 is inserted in the first direction H1 from the side through hole 14A of the valve mounting wall 14. Then, when it is inserted to the back of the through hole 28, the first step surface 71D of the ring portion 71 abuts against the second step surface 28D of the through hole 28, the small outer diameter portion 73 of the ring portion 71 fits into the second inner surface 28B of the through hole 28, and the large outer diameter portion 72 of the ring portion 71 is pressed against the first inner surface 28A of the through hole 28. Then, the rectifier 70 is fixed to the inner surface of the through hole 28 by the sealant applied in advance to the outer surface of the ring portion 71. At this time, the main plane 74A of the partial blocking wall 74 facing the measurement room 31 is positioned so as to be flush with the side surface 25A of the first partition wall 25 facing the measurement room 31. On the other hand, the tip of the annular protrusion 75 is positioned so as not to protrude from the through hole 28 in the first direction H1.

The configuration of the gas meter 10A of this embodiment has been described above. Next, the action and effect of this gas meter 10A will be described. In the gas meter 10A of this embodiment, as shown in FIG. 3, the fuel gas from the gas supply source pipe 99 flows downward through one of the connecting pipes 23 into the meter case 11. In the meter case 11, the fuel gas flows through the inflow chamber 30, the measurement chamber 31, the measurement pipe 50, and the outflow chamber 33, which are arranged in the first direction H1, in that order, and then flows upward through the other connecting pipe 24 and out into the pipe 99 on the fuel gas user side. The flow rate is measured using a pair of ultrasonic elements attached to the measurement pipe 50. Here, in the event of an abnormality, the through hole 28 provided in the first partition wall 25 separating the inflow chamber 30 and the measurement chamber 31 is blocked from the inflow chamber 30 side by the valve body 21 of the shutoff valve 20, and the inflow of fuel gas into the measurement chamber 31 is blocked. In this embodiment, a ring portion 71 is provided that fits into the inner surface of the through hole 28, and the ring portion 71 is provided with an annular protrusion 75 as a valve seat against which the valve body 21 of the shutoff valve 20 abuts in the event of an abnormality, and a partial blocking wall 74 for rectifying the fuel gas flowing into the measurement pipe 50. In this way, in the gas meter 10A of this embodiment, the valve seat and the structure for rectifying the flow are integrally formed, so that the number of parts to be assembled to the meter case 11 can be reduced.

The partial blocking wall 74 faces the entire end opening 50A of the measuring pipe 50 inside the ring portion 71 in the first direction H1. Therefore, even if the fuel gas flowing into the inlet chamber 30 is in a turbulent state when it passes through a partial opening 74K inside the ring portion 71 that is not provided with a partial blocking wall 74, the fuel gas can be rectified so that it flows into the measuring pipe 50 in a laminar state by flowing upward along the surface of the partial blocking wall 74 and then changing direction toward the end opening 50A side of the measuring pipe 50 (first direction H1).

The partial blocking wall 74 covers the upper half of the inside of the ring portion 71, and since the fuel gas flows from one of the connecting pipes 23 from above to below into the inflow chamber 30, the partial blocking wall 74 covers the inflow chamber 30 from the upstream side. Therefore, most of the fuel gas flowing into the inflow chamber 30 from one of the connecting pipes 23 is received by the partial blocking wall 74. As a result, the fuel gas first flows downward along the surface of the partial blocking wall 74, then changes direction and passes through the partial opening 74K, and then flows upward along the surface of the partial blocking wall 74 and changes direction toward the end opening 50A of the measuring pipe 50 (see FIG. 7), so that the fuel gas flowing into the measuring pipe 50 can be further straightened.

Furthermore, in this embodiment, the main plane 74A of the partial blocking wall 74 is arranged flush with the side surface 25A of the first partition wall 25, so that an increase in pressure loss in front of the end opening 50A of the measuring pipe 50 can be suppressed. In addition, the straight portion of the lower edge of the partial blocking wall 74 is arranged parallel to the lower side of the end opening 50A of the measuring pipe 50, so that the fuel gas that flows along the surface of the partial blocking wall 74 can be made to flow uniformly into the measuring pipe 50.

Moreover, in the gas meter 10A of this embodiment, the axial length of the rectifier 70 is smaller than the wall thickness of the first partition wall 25, so that the fuel gas flowing into the measurement pipe can be rectified with a compact structure that fits inside the through hole 28.

The rectifier 70 can be easily assembled by inserting it into the inflow chamber 30 from the side through-hole 14A of the meter case 11 and abutting the first step surface 71D of the ring portion 71 against the second step surface 28D of the through-hole 28. Moreover, the inner surface of the inflow chamber 30 is a cylindrical inner surface that opens at the side through-hole 14A and the through-hole 28 and expands in diameter toward the side through-hole 14, and has a shape with a second step surface 28D that expands in diameter on the side through-hole 14A side, so no complicated processing is required.

[Other embodiments]
(1) As shown in Fig. 8(A) and (B), a plurality of ventilation holes 74T may be formed through the partial blocking wall 74. According to this configuration, the flow of the fuel gas flowing into the inflow chamber 30 is made uniform by passing through the plurality of ventilation holes 74T. Note that each ventilation hole 74T may be configured to have a regular hexagon with a pair of opposite sides extending in the up-down direction, for example, and arranged on a plurality of imaginary circles concentric with the partial blocking wall 74.

Alternatively, the partial blocking wall 74 may block the entire inside of the ring portion 71, and multiple ventilation holes 74T may be formed throughout the entire partial blocking wall 74.

(2) In the above embodiment, the rectifier 70 of the gas meter 10A is configured such that the main plane 74A of the partial blocking wall 74 is flush with the side surface 25A of the first partition wall 25. However, as in the gas meter 10B shown in FIG. 9, the main plane 74A of the partial blocking wall 74 may protrude toward the measurement pipe 50 beyond the side surface 25A of the first partition wall 25.

(3) In the gas meters 10A and 10B of the above embodiment, the partial blocking wall 74 is disposed at the end of the ring portion 71 on the side of the measurement room 31, but it may be disposed in the middle part of the ring portion 71 in the axial direction.

(4) In the gas meters 10A and 10B of the above embodiment, the tip of the annular protrusion 75 is positioned so as not to protrude from the through hole 28 in the first direction H1, but it may protrude from the through hole 28 in the first direction H1.

(5) In the gas meters 10A and 10B of the above embodiment, the rectifier 70 is a molded product made of aluminum or brass, but it may also be a molded product made of resin.

(6) In the gas meters 10A and 10B of the above embodiment, the ring portion 71 is configured to include an annular protrusion 75 and a partial blocking wall 74. However, for example, as in the gas meter 10C shown in FIG. 10, the annular protrusion 75 that serves as the valve seat may be removed from the rectifier 70C, and instead, an annular protrusion 21B may be provided on the valve body 21 of the shutoff valve 20, and a tapered surface 28T may be provided with which the protrusion 21B abuts against the opening edge of the through hole 28 on the inlet chamber 30 side.

(7) In the gas meters 10A, 10B, and 10C of the above-described embodiments, the duct portion 12 extends horizontally and the pair of connecting pipes 23, 24 protrude upward. However, the present invention may be applied to a gas meter in which the pair of connecting pipes 23, 24 protrude downward, or one of the connecting pipes 23, 24 protrudes above and one below the duct portion 12, or further, a gas meter in which the duct portion 12 extends vertically and the pair of connecting pipes 23, 24 protrude horizontally.

(8) The gas meters 10A, 10B, and 10C in the above embodiments are configured to measure the flow rate of fuel gas using ultrasonic elements, but the principle of measuring the flow rate may be any.

Note that although specific examples of the technology included in the scope of the claims are disclosed in this specification and drawings, the technology described in the claims is not limited to these specific examples, but includes various modifications and variations of the specific examples, as well as parts of the specific examples taken separately.

10A, 10B, 10C Gas meter 11 Meter case 20 Shutoff valve 21 Valve body 25 First partition wall (partition wall)
28 Through hole 30 Inflow chamber 31 Measurement chamber 50 Measurement pipe 50A End opening 70 Flow straightener 71 Ring portion 74 Partial blocking wall 74K Partial opening 75 Annular protrusion (valve seat)
H1 First direction

Claims (7)

a meter case having an inflow chamber adjacent to a measurement chamber for measuring a flow rate of a gas, in which gas flowing into the inflow chamber from a second direction perpendicular to a first direction in which the measurement chamber and the inflow chamber are aligned flows into the measurement chamber through a through hole penetrating a partition wall between the inflow chamber and the measurement chamber;
a rectifier that rectifies the gas flowing from the inlet chamber to the measurement chamber;
a shutoff valve having a valve body that closes the through hole from the inflow chamber side in the event of an abnormality,
The gas meter includes a ring portion, the rectifier being fitted and fixed in the through hole, and a valve seat formed on the ring portion and coming into contact with the valve body in the event of the abnormality. the flow straightener includes a partial blocking wall that blocks a part of an inner side of the ring portion, and a partial opening that is not blocked by the partial blocking wall within the inner side of the ring portion,
The measuring chamber contains a measuring pipe having a tubular structure, through which all the gas passing through the measuring chamber passes, and an end opening of the measuring pipe faces the partial closing wall;
2. The gas meter according to claim 1, wherein the flow rate of the gas is measured based on a flow velocity of the gas passing through the measuring pipe. the partial blocking wall is disposed at an end of the ring portion on the measurement room side,
3. The gas meter according to claim 2, wherein a side surface of the partition wall facing the measurement room and a main plane of the partial blocking wall facing the measurement room are disposed flush with each other. An edge portion of the partial closing wall on the partial opening side extends linearly,
4. The gas meter according to claim 2, wherein the end opening of the measuring pipe is rectangular, and one side of the rectangle is arranged parallel to an edge of the partial closing wall on the partial opening side. A gas meter according to any one of claims 2 to 4, wherein the partial blocking wall is disposed on the upstream side of the inlet chamber in the through hole. A gas meter according to any one of claims 1 to 5, wherein the axial length of the rectifier is smaller than the wall thickness of the partition wall. The valve body includes a disk-shaped packing overlapped on a surface facing the through hole,
7. The gas meter according to claim 1, wherein the valve seat is annular, protrudes from the ring portion toward the inflow chamber, and is structured to bite into the packing.

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