JP5069141B2 - Gas meter manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a gas meter.

Conventionally, various gas meters such as a membrane gas meter have been used for gas flow rate measurement. In recent years, an ultrasonic gas meter capable of measuring a flow rate with higher accuracy has been proposed.
For example, in the related art described in Patent Document 1 shown in FIGS. 9 and 10, when the flow rate of the fluid (gas) to be measured flowing from the inlet 11 to the outlet 12 is measured, the measured target flowing through the conduction path 125 is measured. An ultrasonic wave is propagated through the fluid, and the flow rate of the ultrasonic wave is measured by changing the propagation time or propagation speed of the ultrasonic wave according to the flow velocity of the measured fluid.
In this measuring method, generally, when the flow state of the fluid to be measured in the conduction path changes significantly, the measurement error tends to increase. For this reason, in Patent Document 1, the conduction path 125 is divided into a plurality of layers so that the thickness (height in the stacking direction of the plurality of layers) is equalized by the rectifying plate 126 to make the flow velocity distribution uniform or stable. The measurement accuracy is improved.
The gas meter 101 obtains a flow value by integrating the gas flow rate using the correction coefficient (flow coefficient) obtained for each gas meter with respect to the flow rate thus measured, and any gas meter 101 has an accurate flow value. To be able to ask.
JP 2006-64626 A

In order to satisfy the measurement accuracy required for each gas meter with each gas meter, for example, in the inspection process in the manufacture of the gas meter, the above correction coefficient uses fluids (gases) of various flow rates as a reference. A correction coefficient is obtained, and a correction coefficient unique to the gas meter is stored.
In addition, the conduction path 125 (see FIG. 10) for measuring the flow rate is manufactured by assembling a rectifying plate 126 formed of a metal plate to a measurement tube 122 of a resin molded product. In order to improve the measurement accuracy of the flow rate, it is necessary to improve the dimensional accuracy of the measuring tube 122. However, when a plurality of dies are produced, the dimensional variation of each die and the heat during molding of the resin molded product are required. It is difficult to ensure stable dimensional accuracy due to variations in shrinkage and the like. If this variation is within an allowable range that can be corrected by the above correction coefficient, there is no particular problem. However, if the allowable range for correcting the flow rate measurement value is deviated, the measurement tube 122 is discarded and the measurement falls within the allowable range. The tube 122 is exchanged or the mold itself is remade, which requires a lot of labor and cost.
The present invention was devised in view of such a point, and provides a method for manufacturing a gas meter that can be reused without discarding a measuring tube that is out of an allowable range for correcting a flow rate measurement value. The issue is to provide.

As means for solving the above-mentioned problems, the first invention of the present invention is a gas meter manufacturing method as described in claim 1.
The method of manufacturing a gas meter according to claim 1 is provided inside the gas meter and has a cylindrical shape in which a gas flow path is formed in a hollow portion having a rectangular cross section, and the flow path has a predetermined interval. Is divided into a plurality of layers by a plurality of thin plate-like rectifying plates arranged in the above, and a measurement configured to measure the flow rate of the gas flowing through the flow path based on a detection result by a predetermined detection means The present invention relates to a method for manufacturing a gas meter having a tube.
First, the measuring tube to which the plurality of rectifying plates are assembled is disassembled, the rectifying plates are rearranged, and the structure can be reassembled.
Further, as for the plurality of rectifying plates arranged at a predetermined interval, the concave shape of the warping shape of the nth rectifying plate is a warped shape in which the rectifying plate is not flat but slightly bent with respect to the gas flow direction. In arranging the warped concave shape and the convex shape so that the warped convex shape of the mth current plate faces the direction of the first current plate, and the convex shape of the mth current plate faces the direction of the first current plate. A first arrangement of the rectifying plates, in which a measured value of the gas flow rate tends to decrease or a correction coefficient for correcting the measured value of the gas flow rate tends to increase from among a plurality of arrangement methods; Among the arrangement methods, there are at least two kinds of the second arrangement method of the rectifying plates in which the measurement value of the gas flow rate tends to increase or the correction coefficient for correcting the measurement value of the gas flow rate tends to decrease. Select the arrangement method in advance To keep.
First, as an arbitrary arrangement, a gas pipe is assembled using a measurement pipe assembled with the rectifying plate, and a reference flow rate gas is used to measure a value measured with respect to the reference flow rate in each gas meter, or the correction with respect to the reference flow rate. If the measured value is out of the allowable range and deviates in a small direction, or the calculated correction coefficient is out of the allowable range and deviates in a large direction, disassemble the measuring tube in the gas meter. In this case, the rectifying plates are rearranged in the second arrangement and the measuring tube is assembled again, and the obtained measurement value deviates from the allowable range and deviates in the large direction, or the obtained correction coefficient deviates from the allowable range and is small. If the measurement tube is not aligned, the measurement tube in the gas meter is disassembled, the rectifying plates are rearranged in the first arrangement, and the measurement tube is assembled again. Kicking, it is a method of manufacturing a gas meter.

A second invention of the present invention is a gas meter manufacturing method as set forth in claim 2.
The method for manufacturing a gas meter according to claim 2 is the method for manufacturing a gas meter according to claim 1, and the measured value of the gas flow rate tends to be near the center from among a plurality of arrangement methods, or A third arrangement of the rectifying plates in which the correction coefficient for correcting the measured value of the gas flow rate tends to be near the center is selected in advance.
First, as an arbitrary arrangement, a gas pipe is assembled using a measurement pipe assembled with the rectifying plate, and a reference flow rate gas is used to measure a value measured with respect to the reference flow rate in each gas meter, or the correction with respect to the reference flow rate. Instead of obtaining a coefficient, first, as a third arrangement, a gas meter is assembled using a measurement pipe assembled with the rectifying plate, and a measured value with respect to the reference flow rate in each gas meter using a reference flow rate gas. Or a method of manufacturing a gas meter, wherein the correction coefficient for the reference flow rate is obtained.

A third invention of the present invention is a gas meter manufacturing method as set forth in claim 3.
A gas meter manufacturing method according to claim 3 is the gas meter manufacturing method according to claim 1 or 2, wherein five rectifying plates are arranged at predetermined intervals in the measurement pipe, and the first In this arrangement, the second rectifying plate is arranged so that the concave shape faces the direction of the first rectifying plate, and the fourth rectifying plate is arranged so that the convex shape faces the direction of the first rectifying plate. It is a manufacturing method.

A fourth invention of the present invention is a gas meter manufacturing method as set forth in claim 4.
A gas meter manufacturing method according to claim 4 is the gas meter manufacturing method according to claim 1 or 2, wherein five rectifying plates are arranged at predetermined intervals in the measurement pipe, and the second In this arrangement, the second rectifying plate is arranged so that the convex shape faces the direction of the first rectifying plate, and the fourth rectifying plate is arranged so that the concave shape faces the direction of the first rectifying plate. It is a manufacturing method.

A fifth aspect of the present invention is a gas meter manufacturing method as set forth in the fifth aspect.
The gas meter manufacturing method according to claim 5 is the gas meter manufacturing method according to claim 2, wherein five rectifying plates are arranged at predetermined intervals in the measurement tube, and the third arrangement method is performed. Then, the second and fourth rectifying plates are arranged so that the concave shape faces the direction of the first rectifying plate and the third rectifying plate is arranged so that the convex shape faces the direction of the first rectifying plate, or The second and fourth rectifying plates are arranged so that the convex shape faces the direction of the first rectifying plate, and the third rectifying plate is arranged so that the concave shape faces the direction of the first rectifying plate. It is a manufacturing method.

In the gas meter manufacturing method according to the first aspect, first, the configuration of the measurement tube is disassembled, the rectifying plates are rearranged, and the assembly can be reassembled. Further, in arranging the current plates, a method of arranging the tendency of the measured value to be small (correction coefficient is large) and a method of arranging the tendency of the measurement value to be large (the correction coefficient is small) are selected in advance.
In this way, first, a gas meter is assembled using a measuring tube with an arbitrary arrangement of rectifying plates and inspected at a reference flow rate. If the measured value is small (correction coefficient is large), the measuring tube is temporarily discarded without being discarded. What is necessary is just to assemble again and re-inspect as a way of arranging the tendency that the measurement value becomes large by decomposing and the correction coefficient becomes small. If the measurement value is large (the correction coefficient is small), the measurement tube may be once disassembled without discarding the measurement tube, and the measurement value may be reduced (increase the correction coefficient).
In this way, it becomes possible to reuse a measuring tube that is out of the permissible range for correcting the flow rate measurement value without discarding it, and there is no waste. In addition, the inspection procedure will be clear and the inspection time can be shortened.

Further, in the gas meter manufacturing method according to claim 2, in the initial assembly of the gas meter, the arrangement of the rectifying plates is not an arbitrary arrangement, so that the probability that the measured value is near the center is increased. The third way of arrangement.
As a result of the inspection of the assembled gas meter, it can be expected that the case where the measurement value is small (the correction coefficient is large) or the measurement value is large (the correction coefficient is small) can be reduced, and the correction (disassembly and reassembly) and Reduction of re-inspection can be expected.

  In the gas meter manufacturing method according to claim 3, the orientation of the second and fourth rectifying plates is set to the orientation shown in FIG. 6A in the direction of the warped shape of the five rectifying plates. Thus, it is possible to arrange the tendency in which the measured values are small (the correction coefficient is large).

  Further, in the gas meter manufacturing method according to claim 4, in the direction of the warped shape of the five rectifying plates, the direction of the second and fourth rectifying plates is set to the direction shown in FIG. 6 (B). Thus, it is possible to arrange the measured values to increase (correction coefficient decreases).

  Further, in the gas meter manufacturing method according to claim 5, the orientation of the second, third, and fourth rectifying plates in the direction of the warped shape of the five rectifying plates is changed to that shown in FIG. By setting the orientation shown in D), it is possible to arrange the measured values so that they tend to be near the center (the correction coefficient is near the center).

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 (A) and 1 (B) show schematic external views of an embodiment of a gas meter 1 manufactured using the method for manufacturing a gas meter of the present invention.

● [Appearance of gas meter 1 (FIGS. 1A and 1B)]
The external appearance of the gas meter 1 of this Embodiment is demonstrated using FIG. 1 (A) and (B). FIG. 1A shows a front view, and FIG. 1B shows a top view. In addition, the X-axis, Y-axis, and Z-axis in each figure are axes in which the X-axis and Y-axis indicate the horizontal direction, and the Z-axis is an axis that indicates the vertical direction.
On the front face of the gas meter 1, there are provided display means 41 (LCD or the like) for displaying an integrated value of the measured gas flow rate, a return button 42 for returning from a state where the gas is shut off by the shut-off valve 34 due to abnormality detection, and the like. It has been.
The gas meter 1 described in the present embodiment has a substantially rectangular box shape, and has a cylindrical substantially U-shaped flow path in which an inflow port 11 and an outflow port 12 are arranged in the same direction. The member 10 is formed as an integrally molded product, and the flow path member 10 constitutes an upper surface, a right side surface, and a left side surface in the appearance of the gas meter 1.
In addition, although the flow path through which the inflowed gas flows in the gas meter 1 is formed in a substantially U shape (see FIG. 3A), in order to integrally form a cylindrical substantially U shape, U It is difficult to insert and remove the mold inside the cylinder at the bottom of the letter shape. Therefore, the bottom side is integrally formed in an open shape, the measuring tube 22 is assembled from the opening, and the bottom panel member 21 is assembled so as to cover the opening (see FIGS. 2 and 3A). Thereby, it becomes easy to integrally form a cylindrical substantially U-shaped flow path.
In the gas meter 1 of the present embodiment, the material of the flow path member 10 is aluminum die casting that uses aluminum that is suitable for integral molding and has a relatively low coefficient of thermal expansion. However, the present invention is not limited to this. Absent.

● [Structure of gas meter 1 (FIGS. 2 to 4)]
Next, the structure of the gas meter 1 will be described with reference to FIGS.
FIG. 2 shows an example of the schematic shape and assembly direction of parts to be assembled to the gas meter 1. 3A shows an example of a cross-sectional view taken along line AA in FIG. 1B (power supply pack 32 and the like are omitted), and FIG. 3B is a cross-sectional view taken along line BB in FIG. The example of a figure is shown, and FIG. 4 has shown the example of CC sectional drawing in FIG. 3 (A). As shown in FIG. 3A, the gas flow path from the inflow port 11 to the outflow port 12 is formed in a substantially U-shaped cylindrical shape.

In the conventional gas meter 101 shown in FIGS. 9 and 10, a substantially U-shaped cylindrical flow path is connected to a back cover 150 having an inlet 11 and an outlet 12, and a first inlet 11 connected to the inlet 11 portion. A measurement pipe case 152 that houses the flow path member 151, the second flow path member 154 connected to the outflow port 12, the measurement pipe 122 and connects the first flow path member 151 and the second flow path member 154; 153. For this reason, since the number of parts to be assembled is large and the structure is complicated and each has a different error, the work of assembling in a sealed state so as not to cause gas leakage takes much labor.
On the other hand, in the gas meter 1 described in the present embodiment, the measurement tube 22 is assembled from the opening provided in the bottom side of the flow path member 10 formed as an integrally molded product, and the bottom is configured to cover the opening. Since only a panel member 21 is assembled, a substantially U-shaped cylindrical flow path from the inlet 11 to the outlet 12 can be formed, so that the assembly is very easy and the workability is good (FIG. 2). FIG. 3A).

Next, with reference to FIG. 2, the schematic shape of the parts to be assembled in the gas meter 1 and the assembly procedure will be described.
First, when the inflow port 11 and the outflow port 12 are arranged in the same direction, the integrally formed flow path member 10 is provided on the bottom surface of the flow path member 10 when the inflow port 11 and the outflow port 12 are on the upper surface. From the opened opening, the measuring tube 22 is assembled so that the measuring tube 22 is disposed in the flow path. And the bottom panel member 21 is assembled | attached to an opening part, and an opening part is sealed (covered). In addition, a pair of ultrasonic propagation means 23A and 23B (ultrasonic transmission / reception sensors) are assembled in the attachment holes of the ultrasonic propagation means provided in the flow path member 10.
The measurement tube 22 has a conduction path 25 that is disposed in the flow path and has a substantially rectangular cross section through which the gas flowing in the flow path passes. The pair of ultrasonic wave propagation means 23A and 23B are arranged at predetermined locations on the upstream side and the downstream side in the conduction path 25, and between these two points, an ultrasonic wave is transmitted from the upstream side and received on the downstream side. The propagation time is measured and the ultrasonic wave is transmitted from the downstream side and received at the upstream side to measure the propagation time. The ultrasonic propagation means 23A, 23B (ultrasonic transmission / reception sensors) are assembled so as to face each other with a predetermined angle “θ” with respect to the fluid flow direction. Here, when the sound velocity is “C”, the gas flow velocity is “U”, the distance (distance) between the ultrasonic wave propagation means 23A and 23B is “L”, and the ultrasonic wave propagation time is “T1”, “T2”, From upstream to downstream (propagation time “T1”), the relationship “T1 = L / (C + Ucos θ)” is established, and from downstream to upstream (propagation time “T2”), “T2 = L / (C−Ucos θ)”. The relationship is established. When the flow velocity “U” is calculated from both equations, “U = (L / 2 cos θ) ((1 / T1) − (1 / T2))” is obtained. Then, the flow rate is calculated by integrating the calculated flow velocity U with the cross section S of the conduction path 25 and the flow coefficient. Here, the flow rate coefficient is a coefficient for correcting the flow rate of the fluid, which will be described later. A plurality of rectifying plates 24 are provided in the conduction path 25 to divide the conduction path 25 into multiple layers to regulate the gas flow.

Next, the shut-off valve 34 is assembled from the back side of the flow path member 10 to the shut-off valve mounting hole provided on the back side of a part of the substantially U-shaped flow path of the flow path member 10. An attachment hole for assembling the shut-off valve 34 is provided in advance at a predetermined location of the flow path on the back side of the flow path member 10 and is integrally formed. The shutoff valve 34 closes (shuts down) the flow path when an abnormality is detected, and prevents gas from flowing into the outlet 12.
Next, the power pack 32 is assembled from the front side of the flow path member 10 into the space K provided in the vicinity of the center of the flow path member 10. And the pressure sensor 31 is assembled | attached to the attachment hole for pressure sensors provided in the one part front side of the substantially U-shaped flow path of the flow path member 10. FIG. A mounting hole for assembling the pressure sensor 31 is provided in advance at a predetermined location of the flow path on the front side of the flow path member 10 and is integrally formed. The pressure sensor 31 detects the pressure of the gas used under conditions for detecting various abnormalities.
Next, the control board 33 (corresponding to the control means) is assembled from the front side of the flow path member 10. The control board 33 includes a CPU and the like, and controls the ultrasonic propagation means 23A and 23B to calculate the flow rate of the gas flowing in the conduction path 25 based on the detection signals from the ultrasonic propagation means 23A and 23B.
Then, the back panel member 50 is assembled from the back side of the flow path member 10, and the front panel member 40 is assembled from the front side of the flow path member 10. Note that the CPU of the control board 33 calculates the pressure from the detection signal of the pressure sensor 31, performs various abnormality determinations, and when an abnormality is determined, outputs a drive signal to the shutoff valve 34 to block the flow path.
With the above assembly, the upper surface portion and the left and right side surface portions are configured by the flow path member 10, the bottom surface portion is configured by the bottom panel member 21, the back surface portion is configured by the back panel member 50, and the front surface portion is the front panel member 40. The substantially box-shaped gas meter 1 configured is completed.

● [Structure of measuring tube 22 (FIG. 5)]
Next, the internal structure of the measurement tube 22 will be described with reference to FIG. The measurement tube 22 is a cylindrical shape having a hollow portion having a rectangular cross section S by two measurement tube upper members 22a and measurement tube lower members 22b whose cross sections perpendicular to the fluid flow direction are “L” -shaped. It is configured to be joined. In this connection, five rectifying plates 24 are accommodated inside. Grooves 22z for sandwiching the respective rectifying plates 24 are respectively provided in contact portions of the inner walls of the measuring tube upper member 22a and the measuring tube lower member 22b with the respective rectifying plates 24, and rectification is performed in the grooves 22z. A plate 24 is positioned and supported.
Further, in the measurement tube upper member 22a and the measurement tube lower member 22b, a protruding portion 22x or a recessed portion 22y is provided at each contact portion when the measuring tube upper member 22a and the measured tube lower member 22b are joined to each other. At 22y, the measurement tube upper member 22a and the measurement tube lower member 22b are positioned.

Here, when the measurement tube upper member 22a and the measurement tube lower member 22b are formed in a “U” shape, a draft is essential, and therefore, a cross section S (cavity) by a plane perpendicular to the direction of fluid flow in the measurement tube 22. Each corner of the partial cross section) is not a right angle, and the accuracy of the cross section S may vary. Further, when the rectifying plate 24 is insert-molded into the measuring tube 22, since a draft is necessary, a problem may occur in the accuracy of the cross section S (the required accuracy cannot be satisfied).
However, in the present embodiment, since the measurement tube upper member 22a and the measurement tube lower member 22b are formed in an “L” shape, no draft is necessary. For this reason, it is possible to make each angle of the cross section S a right angle. For example, even if the measurement tube upper member 22a and the measurement tube lower member 22b are formed using resin, the area accuracy can be sufficiently secured. .
In addition, a turbulent flow suppressing member is provided in the opening 22c (corresponding to the attachment position of the ultrasonic wave propagation means) so as to form substantially the same surface as the inner wall on the inner wall side.

In the gas meter 1 described in the present embodiment, in order to keep the measurement value of the gas flow rate with the required accuracy, the measurement result is inspected using the gas of the reference flow rate with each gas meter so as to satisfy the required accuracy. The correction coefficient is obtained, and the obtained correction coefficient is stored in a storage means provided on the control board 33.
Each gas meter takes in the individual error of the measurement tube 22, the individual error of the ultrasonic wave propagation means 23A and 23B, and the detection signal of the ultrasonic wave propagation means 23A and 23B, and calculates the measurement value. Due to an error or the like, the measured value is deviated in the direction of increasing or decreasing with respect to the ideal state. Therefore, conventionally, the deviation is absorbed by obtaining and storing a correction coefficient unique to each gas meter.
However, in some cases, a gas meter is generated that falls outside the allowable correction range that can be corrected by the correction coefficient. Conventionally, if the correction coefficient cannot be adjusted, the measuring tube 22 of the gas meter is discarded and replaced with a new measuring tube 22.

  In the gas meter manufacturing method described in the present embodiment, as will be described below, even if the gas meter is out of the correction allowable range, the measurement tube 22 is not discarded, and the measurement is performed within the correction allowable range. This is a method of reassembling the tube 22.

● [Direction of warping shape of rectifying plate 24 in measurement tube 22 and tendency of measured value (correction coefficient) (FIGS. 6 and 7)]
First, as shown in FIG. 5 (A), the measuring tube 22 can be placed in the state shown in FIG. 5 (B) by arranging and assembling each rectifying plate 24 (using a jig). From the assembled state shown in FIG. 5 (B), the structure can be disassembled as shown in FIG. 5 (A), the rectifying plates 24 can be rearranged and assembled again into the state shown in FIG. 5 (B). And
In the present embodiment, the measurement tube 22 is a resin molded product, the rectifying plate 24 is a metal plate such as stainless steel, and has a fitting type structure, so that it can be disassembled and reassembled.
In addition, the rectifying plate 24 is not flat with respect to the gas flow direction but is slightly warped (for example, warped by about 0.1 mm to 0.2 mm). The arrangement of the warp-shaped irregularities is such that the n-th rectifying plate is oriented so that the convex shape faces the first rectifying plate, and the m-th rectifying plate is oriented so that the concave shape faces the first rectifying plate. Line up. In this arrangement of the rectifying plates, the measurement value is controlled to be large (or small) by using the arrangement method in which the measurement value is increased and the arrangement method in which the measurement value is decreased.

Therefore, a first arrangement in which the measured values tend to be smaller (that is, the correction coefficient tends to be larger) and a tendency that the measured values are larger (that is, the correction coefficient is smaller) from among a plurality of warped shape arrangement methods. (Tendency) is selected in advance, and the third arrangement is selected in advance so that the measured value tends to be near the center (that is, the correction coefficient tends to be near the center).
The inventor selected combinations shown in FIGS. 6 (A) to 6 (D) as a result of experiments in various arrangements on a large number of gas meters. 6A to 6D are schematic diagrams for clarifying the direction of the uneven shape when the number of the current plates 24 is five as an example. It is highlighted and emphasized.

  In the arrangement shown in FIG. 6A (hereinafter referred to as “arrangement A”), which is the first arrangement, in the five rectifying plates 24, the second rectifying plate 24 (2) has the concave shape as the first. The fourth rectifying plate 24 (4) is arranged so as to face the direction of the rectifying plate 24 (1) and the convex shape thereof is directed to the direction of the first rectifying plate 24 (1). In this case, the orientation of the first rectifying plate 24 (1), the third rectifying plate 24 (3), and the fifth rectifying plate 24 (5) may be any direction.

  In the second arrangement method shown in FIG. 6B (hereinafter, referred to as “arrangement method B”), in the five rectifying plates 24, the second rectifying plate 24 (2) has the first convex shape. The fourth rectifying plate 24 (4) is arranged so as to face the direction of the rectifying plate 24 (1) and the concave shape thereof is directed to the direction of the first rectifying plate 24 (1). In this case, the orientation of the first rectifying plate 24 (1), the third rectifying plate 24 (3), and the fifth rectifying plate 24 (5) may be any direction.

  The third arrangement method corresponds to the arrangement method shown in FIGS. 6C and 6D (hereinafter referred to as “arrangement method C” and “arrangement method D”). In the “arrangement method C”, in the five rectifying plates 24, the second rectifying plate 24 (2) and the fourth rectifying plate 24 (4) are directed in the direction of the first rectifying plate 24 (1). Then, the third rectifying plate 24 (3) is arranged so that the convex shape faces the direction of the first rectifying plate 24 (1). In “Arrangement D”, in the five rectifying plates 24, the second rectifying plate 24 (2) and the fourth rectifying plate 24 (4) are directed in the direction of the first rectifying plate 24 (1). In addition, the third current plate 24 (3) is arranged so that the concave shape faces the direction of the first current plate 24 (1). In this case, the direction of the first rectifying plate 24 (1) and the fifth rectifying plate 24 (5) may be any direction.

  FIG. 7 and FIG. 8 show, as an example, five gas meters taken as samples, and the results of calculating the correction coefficient in each of the above “arrangement methods A” to “arrangement method D” are shown. Any gas meter tends to have a large correction coefficient (that is, the measurement value tends to be small) in “Arrangement A”, and tends to have a small correction coefficient (that is, the measurement value tends to be large) in “Arrangement B”. It can be seen that the “arrangement method C” and “arrangement method D” tend to have a correction coefficient in the vicinity of the center (that is, the measurement value tends to be in the vicinity of the center).

● [Gas meter manufacturing method]
When assembling the gas meter 1 in the production line, first, the gas meter 1 is assembled by using the measuring tube 22 assembled in the third arrangement method “arrangement method C” or “arrangement method D” with the concavo-convex shape of the current plate.
Then, in the inspection process for obtaining and storing the correction coefficient, the correction coefficient for the reference flow rate is obtained. If the obtained correction coefficient is within the correction allowable range, the correction coefficient may be stored in the gas meter.
When the obtained correction coefficient deviates from the correction allowable range and deviates in a large direction, the correction coefficient only needs to be reduced. Therefore, the measurement tube 22 is once disassembled and rectified so as to become “arrangement B”. The plates 24 are rearranged, the measuring tube 22 is assembled again, and reinspected.
Further, when the obtained correction coefficient deviates from the correction allowable range and deviates in a small direction, the correction coefficient only needs to be increased. Therefore, the measurement tube 22 is disassembled once so that the “arrangement A” is obtained. The current plates 24 are rearranged, the measuring tube 22 is assembled again, and reinspected.
In this way, the measuring tube 22 outside the allowable range for correcting the flow rate measurement value can be reused without being discarded, and there is no waste. In addition, the inspection procedure (repairing procedure) becomes clear, and shortening of the inspection and reworking time can be expected.

In the gas meter manufacturing method described above, a first arrangement method to a third arrangement method are selected from a plurality of arrangement methods in advance, and in assembling the gas meter, first, a measurement tube in which rectifying plates are arranged in the third arrangement method. 22 was used. When the gas meter is first assembled with the expectation that the obtained correction coefficient is likely to be near the center, the third arrangement is used.
However, without selecting the third arrangement method, the first arrangement method and the second arrangement method may be selected, and first, the gas meter may be assembled using the measuring tube 22 in which the rectifying plates are arranged in an arbitrary arrangement method. . Of course, if the calculated correction coefficient is within the correction allowable range, it may be stored in the gas meter as it is. If the calculated correction coefficient is outside the correction allowable range and deviated in a large direction, the measuring tube 22 is once disassembled. Then, the rectifying plates 24 may be rearranged so that the “arrangement method B” is obtained, the measuring tube 22 is assembled again, and the inspection is performed again. If the obtained correction coefficient deviates from the correction allowable range and deviates in a small direction, the measuring tube 22 is once disassembled, the rectifying plates 24 are rearranged so as to be “arrangement A”, and the measuring tube is again formed. 22 may be assembled and re-inspected.

  It should be noted that the error that the correction coefficient is not in the vicinity of the center but in a larger or smaller direction is not only due to the error of the measuring tube 22, but is also due to an error due to the characteristic deviation of the ultrasonic wave propagation means (ultrasonic wave transmitting / receiving sensor) or the ultrasonic wave propagation. This is an error of the entire measurement system, including an error due to a characteristic shift of an electronic circuit on the control board that takes in a detection signal from the means, and is an error inherent to the gas meter. The error in the entire measurement system is a very effective method in that the gas meter manufacturing method of the present invention can reduce the error by rearranging the rectifying plates 24 of the measurement tube 22. The reduced error can be corrected with a correction coefficient.

The manufacturing method of the gas meter of the present invention is not limited to the method and procedure described in the present embodiment, and various modifications, additions and deletions can be made without changing the gist of the present invention. For example, the number of rectifying plates 24 is not limited to five, and the arrangement order of the uneven directions in the first to third arrangement methods is not limited to that described in the present embodiment.
Further, the characteristics such as the graph used in the description of the present embodiment are examples, and the present invention is not limited to these characteristics.
In the description of the present embodiment, the gas meter 1 having the substantially U-shaped flow path with the inflow port 11 and the outflow port 12 facing upward has been described, but the inflow port 11 and the outflow port 12 are directed downward. An inverted U-shaped gas meter can also be configured.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.

1 is a schematic external view of a gas meter 1 of the present invention. It is a figure which shows the example of the schematic shape and assembly direction of the components assembled | attached to the gas meter. It is a figure explaining the example of an AA sectional view in Drawing 1 (B) (Drawing 3 (A)), and an example of a BB sectional view in Drawing 3 (A). It is a figure explaining the example of CC sectional drawing in FIG. 3 (A). It is a figure explaining the example of the structure of the measurement pipe | tube 22 which can be decomposed | disassembled and reassembled. It is a figure explaining the example of the 1st arrangement method-the 3rd arrangement method which shows how to arrange the uneven | corrugated shape of a baffle plate. It is a figure (graph) which shows the measurement result of the relation between the flow rate and the correction coefficient in each case where the measurement pipes 22 are “arrangement method A” to “arrangement method D” for the gas meter extracted as a sample. It is a figure (graph) which shows the measurement result of the relation between the flow rate and the correction coefficient in each case where the measurement pipes 22 are “arrangement method A” to “arrangement method D” for the gas meter extracted as a sample. It is a figure explaining the example of the external appearance of the conventional gas meter 101. FIG. It is a figure explaining the internal structure (especially component which forms a flow path) of the conventional gas meter 101. FIG.

1 Gas meter 10 Channel member (integral molded product)
DESCRIPTION OF SYMBOLS 11 Inflow port 12 Outlet port 21 Bottom panel member 22 Measuring pipe 23A, 23B Ultrasonic propagation means 24 Current plate 25 Conduction path 31 Pressure sensor 32 Power supply pack 33 Control board (control means)
34 Shutoff valve 40 Front panel member 41 Display means 42 Return button 50 Back panel member K Space part

Claims (5)

Provided inside the gas meter,
It has a cylindrical shape in which a gas flow path is formed in a hollow portion having a rectangular cross section,
The flow path is divided into a plurality of layers by a plurality of thin plate-like rectifying plates arranged at a predetermined interval,
In the method of manufacturing a gas meter having a measuring tube configured to measure the flow rate of the gas flowing through the flow path based on a detection result by a predetermined detection unit,
As a structure that can disassemble the measuring tube to which the plurality of rectifying plates are assembled, rearrange the rectifying plates, and re-assemble,
As the warping shape that the current plate is slightly flat rather than flat with respect to the gas flow direction,
About the several baffle plate arrange | positioned by predetermined spacing, the said convex shape of the said warp shape of an nth baffle plate faces the direction of the 1st baffle plate, and the said convex shape of the said warp shape of an mth baffle plate In the arrangement of the warped concave shape and the convex shape so that is directed toward the first current plate,
A first arrangement of the rectifying plates in which a measured value of the gas flow rate tends to decrease or a correction coefficient for correcting the measured value of the gas flow rate tends to increase from among a plurality of arrangement methods;
Among the plurality of arrangement methods, at least two of the second arrangement methods of the rectifying plates in which the measurement value of the gas flow rate tends to increase or the correction coefficient for correcting the measurement value of the gas flow rate tends to decrease. Select how to arrange the streets in advance,
First, as an arbitrary arrangement, a gas meter is assembled using a measurement pipe with the rectifying plate assembled, and a reference flow rate gas is used, and the measured value for the reference flow rate or the correction coefficient for the reference flow rate is calculated for each gas meter. Seeking
When the obtained measurement value deviates from the allowable range and deviates in the small direction, or when the obtained correction coefficient deviates from the allowable range and deviates in the large direction, the measurement tube in the gas meter is disassembled and the second Rearrange the rectifying plate in the way of arrangement, and reassemble the measuring tube,
When the obtained measurement value deviates from the permissible range and deviates in the large direction, or when the obtained correction coefficient deviates from the permissible range and deviates in the small direction, the measurement tube in the gas meter is disassembled and the first Rearrange the rectifying plates in the way of arranging and assemble the measuring tube again,
Gas meter manufacturing method. A method for manufacturing a gas meter according to claim 1,
Furthermore, among the plurality of arrangement methods, there is a tendency that the measured value of the gas flow rate tends to be near the center, or the correction coefficient for correcting the measured value of the gas flow rate tends to be near the center. Select the arrangement method in advance,
First, as an arbitrary arrangement, a gas meter is assembled using a measurement pipe with the rectifying plate assembled, and a reference flow rate gas is used, and the measured value for the reference flow rate or the correction coefficient for the reference flow rate is calculated for each gas meter. Instead of obtaining , first, as a third arrangement, a gas meter is assembled using a measurement pipe assembled with the rectifying plate, and a reference flow rate gas is used to measure a value for the reference flow rate in each gas meter, or Obtaining the correction coefficient for the reference flow rate;
Gas meter manufacturing method. It is a manufacturing method of the gas meter according to claim 1 or 2,
In the measuring tube, five rectifying plates are arranged at a predetermined interval,
In the first arrangement, the second rectifying plate is arranged so that the concave shape faces the direction of the first rectifying plate, and the fourth rectifying plate is arranged so that the convex shape faces the direction of the first rectifying plate. ,
Gas meter manufacturing method. It is a manufacturing method of the gas meter according to claim 1 or 2,
In the measuring tube, five rectifying plates are arranged at a predetermined interval,
In the second arrangement, the second rectifying plate is arranged so that the convex shape faces the direction of the first rectifying plate, and the fourth rectifying plate is arranged so that the concave shape faces the direction of the first rectifying plate. ,
Gas meter manufacturing method. It is a manufacturing method of the gas meter according to claim 2,
In the measuring tube, five rectifying plates are arranged at a predetermined interval,
In the third arrangement,
The second and fourth rectifying plates are arranged so that the concave shape faces the direction of the first rectifying plate, and the third rectifying plate is arranged so that the convex shape faces the direction of the first rectifying plate,
Alternatively, the second and fourth rectifying plates are arranged so that the convex shape faces the direction of the first rectifying plate, and the third rectifying plate is arranged so that the concave shape faces the direction of the first rectifying plate.
Gas meter manufacturing method.

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