JP5022511B1 - Inner case for impeller-type water meter, measuring device for impeller-type water meter, and impeller-type water meter - Google Patents

Abstract

An inner case for an impeller-type water meter, an impeller-type water meter metering device, and an impeller-type that can achieve high accuracy in a small flow rate range and a large flow rate range, and can keep instrumental errors small. Provide a water meter.
A base portion 10 of an inner case has a bottomed cylindrical shape, and has a step surface 16 at an intermediate portion of an outer surface of a peripheral wall viewed in an axial direction h, and a peripheral wall outer surface 130 above the step surface 16 is located on a lower side. It protrudes in the radial direction from the peripheral wall outer surface 131. The measuring chamber 100 is a bottomed cylindrical internal space of the base unit 10. The inflow channel 11 opens to the outer peripheral wall 131 and penetrates the measuring chamber 100. The outflow passage 12 opens to the outer peripheral wall 130 and penetrates the measuring chamber 100. The through hole 18 extends from the inner surface of the outflow passage 12 along the axial direction h and opens to the step surface 16. The on-off valve 3 is attached to the inner surface of the outflow passage 12 and covers the 18 opening end edge of the through-hole so that it can be opened and closed.
[Selection] Figure 1

Description

  The present invention relates to an inner case for an impeller-type water meter, a measuring device for an impeller-type water meter, and an impeller-type water meter.

  For example, Patent Document 1 is known for this type of water meter. The water meter described in Patent Document 1 is a so-called double box type tangential flow impeller water meter, and the tap water flowing into the main body case flows into the measuring chamber through the inflow path below the inner case, and the impeller After rotating up and turning in the measuring chamber while rotating, is discharged through the outflow passage on the upper side of the inner case. The rotational speed of the impeller is transmitted to the display mechanism by magnetic coupling between a magnet mounted on the main shaft of the impeller and a magnet gear in a register box facing the magnet.

  By the way, for water meters, the instrumental difference test is performed based on the specific measuring instrument verification inspection rule (JIS: B8570-2) of the Measurement Law, and the instrumental error may be within the verification tolerance in the predetermined flow rate range. In recent years, there has been a demand for a high-precision water meter that is not only within the test tolerance, but also minimizes instrumental error as much as possible.

  Conventionally, this type of water meter has been designed so that the penetration direction of the inflow channel is substantially tangential to the outer peripheral tip of the impeller, improving the rotational efficiency of the impeller, etc. Often endeavors to make it easier. On the other hand, in order to reduce the instrumental difference in the predetermined flow rate range, it is necessary to realize high accuracy of measurement in a large flow rate region in addition to high accuracy of measurement in a small flow rate region. In particular, the influence of various external effects applied to the rotating impeller, such as frictional force and rotational energy, increases in proportion to the increase in flow rate. In short, the impeller tends to rotate more than the actual flow rate under the influence of the external action in a large flow rate region, and as a result, there arises a problem that the instrumental error increases.

  About the problem mentioned above, in the invention described in patent document 1, this cannot be eliminated. For example, the water meter described in Patent Document 1 is provided with a weir in the inflow channel, and guides a part of the tap water to the lower side of the measuring chamber, thereby eliminating the adverse effect applied to the impeller as the flow rate increases. It is something to try.

  However, in the invention described in Patent Document 1, since the inflow of tap water into the measuring chamber is eventually allowed, the adverse effect on the impeller caused by the inflowing tap water cannot be completely eliminated. The instrumental error cannot be kept small.

JP 2010-243442 A

  The subject of this invention is providing the inner case for impeller-type water meters which can suppress an instrument difference small, the measuring apparatus for impeller-type water meters, and an impeller-type water meter.

  Another object of the present invention is to provide an inner case for an impeller-type water meter and an impeller-type water meter that can achieve both high accuracy of measurement in a small flow rate range and high accuracy of measurement in a large flow rate range. A metering device for use and an impeller-type water meter.

  In order to solve the above-described problem, an inner case according to the present invention is used for an impeller-type water meter, and includes a base portion, a measuring chamber, an inflow channel, and an outflow channel. The base portion has a bottomed cylindrical shape, has a step surface at an intermediate portion of the outer surface of the peripheral wall viewed in the axial direction, and the outer surface of the peripheral wall above the step surface protrudes in the outer diameter direction from the outer surface of the lower peripheral wall. . The measurement chamber is a bottomed cylindrical internal space of the base portion. The inflow channel opens to the outer surface of the lower peripheral wall and penetrates the measuring chamber, and the outflow channel opens to the outer surface of the upper peripheral wall and penetrates the measuring chamber.

  The present invention is characterized in that it includes a through hole and an on-off valve in addition to the basic configuration of the inner case for the impeller-type water meter described above. That is, the through hole constituting the inner case according to the present invention extends from the inner surface of the outflow passage along the axial direction and opens to the step surface. According to this configuration, when the inner case is housed in the main body case of the water meter, a part of the tap water flowing into the main body case can be directly sent to the outflow path through the through hole. In other words, when the through hole functions as a bypass, a part of tap water flowing into the main body case can be sent to the outflow path without passing through the measuring chamber of the inner case.

  The on-off valve is attached to the inner surface of the outflow passage, and covers the open end edge of the through-hole so that it can be opened and closed. According to this configuration, the through hole can be opened and closed as the flow rate increases. Specifically, when a large amount of tap water flows into the main body case, the end of the on-off valve that closes the open end of the through hole is passed through the through hole, and the momentum or pushing pressure of the tap water (for example, water pressure) Is transmitted, and the end is pushed up according to the momentum and pressing force of tap water, thereby opening the through hole. As a result, part of the tap water that has flowed into the main body case is sent to the outflow path without passing through the measuring chamber of the inner case by the through-hole bypass function already described.

  On the other hand, when a small amount of tap water flows into the main body case, the on-off valve is not opened and the open end of the through hole remains closed. It will be sent to the outflow passage after passing through the weighing chamber of the case.

  The inner case according to the present invention is combined with a main body case, an impeller, and the like to constitute an impeller-type water meter (water meter). The main body case which comprises the water meter which concerns on this invention has internal space, a partition, and a penetration part. The partition partitions the internal space into an upper side and a lower side when viewed in the height direction. The penetrating portion penetrates the partition wall in the height direction, and connects the upper side and the lower side of the internal space in a water-permeable manner.

  The impeller is housed in the measurement chamber of the inner case and constitutes a metering device for a water meter. The inner case blocks the water flow between the upper side and the lower side of the internal space by pressing the step surface against the opening edge of the penetrating part.

  As already described, the inner case constituting the impeller-type water meter according to the present invention is characterized in that it includes a through hole and an on-off valve in addition to the basic configuration of this type of inner case. . According to this configuration, when a large amount of tap water flows into the main body case, a part of the tap water that flows into the main body case by the bypass function of the through-hole is opened by opening the on-off valve. It will be sent to the outflow channel without passing through the weighing chamber. That is, the amount of inflow into the measurement chamber in the large flow rate region is reduced, and as a result, the adverse effect on the impeller accompanying the increase in the flow rate is eliminated. Therefore, the measurement accuracy in the large flow rate region can be improved. it can.

  The on-off valve has a structure that does not open in a small flow area less than the large flow area. For example, when a small amount of tap water flows into the main body case, the open / close valve is not opened and one end of the through hole is blocked It will be in the state that has been done. As a result, the tap water that has flowed into the main body case rotates the impeller according to the flow rate in the original route (water passage route) that is sent to the outflow passage after passing through the measuring chamber of the inner case. .

  As described above, according to the present invention, it is possible to open and close the through-hole according to the flow rate. Therefore, the measurement accuracy in the small flow rate range is improved, and the measurement accuracy in the large flow rate range is high. It is possible to provide an inner case for an impeller-type water meter, a measuring device for an impeller-type water meter, and an impeller-type water meter in which the instrumental error is kept small in both flow ranges.

As described above, according to the present invention, the following effects can be obtained.
(1) It is possible to provide an inner case for an impeller-type water meter, an impeller-type water meter metering device, and an impeller-type water meter that can suppress instrumental errors.
(2) Impeller-type water meter inner case, impeller-type water meter metering device capable of achieving both high measurement accuracy in a small flow rate range and high measurement accuracy in a large flow rate range, and An impeller-type water meter can be provided.

  Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. The accompanying drawings are merely examples.

It is a fragmentary sectional view of the inner case for impeller-type water meters concerning the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. It is the elements on larger scale which abbreviate | omitted and show a part about the inner case of FIG. It is a perspective view which takes out and shows the on-off valve of FIG. 1 is a perspective view of a weighing device according to an embodiment of the present invention. It is a perspective view which shows the decomposition | disassembly structure of the weighing | measuring apparatus of FIG. It is a fragmentary sectional view of an impeller type water meter concerning an embodiment of the present invention. It is an enlarged front view which omits and shows a part about the use condition of the impeller-type water meter which concerns on this invention. It is an enlarged front view which omits and shows a part about the use condition of the impeller-type water meter which concerns on this invention.

  1 to 10, the same reference numerals denote the same or corresponding parts. In the description of FIGS. 1 to 10, the axial direction of the inner case and the height direction of the main body case 6 are all coincident with each other, and are therefore all indicated by the symbol h.

  The inner case shown in FIG. 1 is used for a so-called double box type tangential flow impeller water meter, and includes a base portion 10, a measuring chamber 100, an inflow passage 11, an outflow passage 12, and a pivot shaft 2. Including.

  The base portion 10 is a cylindrical body having a bottom end and molded using a synthetic resin material, and includes a peripheral wall 13, a bottom portion 14, and an opening 15. The opening 15 opens on the side opposite to the bottom 14 when viewed in the axial direction h.

  The base portion 10 has a changing portion in which the outer dimension increases (or decreases) in the middle of the outer surface of the peripheral wall 13 viewed in the axial direction h, and a step surface 16 corresponding to the dimensional difference g1 is formed in the changing portion. Yes. In other words, in the peripheral wall 13, the outer peripheral wall surface 130 above the step surface 16 protrudes in the radial direction d from the lower peripheral wall outer surface 131.

  The step surface 16 is a surface having the lower end edge of the outer peripheral wall surface 130 as one end (outer end) and the upper end edge of the outer peripheral wall surface 131 as the other end (inner end) when viewed in the radial direction d. It is parallel to the outer surface. The peripheral wall outer surface 130 and the peripheral wall outer surface 131 of FIG. 1 are coaxial, and the step surface 16 appears in a ring shape along the peripheral wall outer surface 131 when viewed from the bottom surface 14.

  In short, the measuring chamber 100 is an internal space of the base portion 10, is partitioned by the peripheral wall 13 and the bottom portion 14, and opens to the outside through the opening 15.

  The inflow channel 11 opens to the outer peripheral wall 131 and penetrates the measuring chamber 100. As shown in FIG. 2, in the inner case, inflow paths 11 are formed at each of a plurality of positions equally arranged in the circumferential direction c on the outer peripheral surface 131. Since the inflow path 11 penetrates the peripheral wall 13 in a direction (substantially tangential direction) obliquely intersecting the radial direction d, a fluid f such as tap water taken into the measurement chamber 100 from the outside through the inflow path 11. Rotates in one direction (for example, counterclockwise direction) below the measuring chamber 100 according to the penetration direction of the inflow passage 11.

  The outflow passage 12 opens to the outer peripheral wall 130 and penetrates the measuring chamber 100. As shown in FIG. 3, in the inner case, outflow passages 12 are formed at each of a plurality of positions that are equally arranged in the circumferential direction c on the outer circumferential surface 130. The outflow path 12 penetrates the peripheral wall 13 in the substantially tangential direction, like the inflow path 11. With this configuration, the fluid f taken into the measuring chamber 100 through the inflow passage 11 rises in the axial direction (h) while turning counterclockwise in the measuring chamber 100, and then passes through the outflow passage 12. It is discharged out of the measuring chamber 100.

  A description will be given with reference to FIG. 1 again. The bottom portion 14 is provided with an embossed portion 17 at the center of the inner surface, and a plurality of ribs (not shown) extend radially from the embossed portion 17. A metal pivot shaft 2 is attached to the center of the embossed portion 17.

  The inner case shown in FIGS. 1 to 3 has a through hole 18 (see FIGS. 3 and 4) and an on-off valve 3 (see FIGS. 4 and 5) in addition to the basic configuration of the inner case for the impeller-type water meter described above. One of the features is that the

  The through hole 18 extends from the inner surface of the outflow passage 12 along the axial direction h and opens to the step surface 16. More specifically, the outflow passage 12 has two inner side surfaces 191 and 192 that face in the circumferential direction c, an upper surface 193 that faces in the axial direction h, and a lower surface 194 (see FIG. 4). The lower surface 194 has a surface region s on the outer side in the radial direction d (see FIG. 3). The surface region s is a surface region that overlaps the step surface 16 when viewed in the axial direction h. A one-dot chain line in FIG. 3 indicates a contour line of the peripheral wall outer surface 131.

  One opening edge of the through hole 18 opens into the surface region s, and further penetrates the upper portion of the peripheral wall 13 from the surface region s in the axial direction h, and opens into the surface of the step surface 16. A gap g <b> 2 is formed between the opening edge of the through hole 18 in the step surface 16 and the lower edge of the outer peripheral wall surface 130. In other words, on the stepped surface 16, a surface region corresponding to the gap g <b> 2 is secured in a portion outside the opening edge of the through hole 18 in the radial direction d. The gap g2 becomes a mounting allowance (mounting space) when the inner case is attached to the main body case of the water meter.

  The outflow passage 12 has a groove 195 that is continuous with the lower surface 194 on the inner surface 191. The groove 195 functions as a female fitting portion of the on-off valve 3, opens to the inner surface 191, and extends along the circumferential direction c.

  The on-off valve 3 in FIGS. 4 and 5 is attached to the inner surface of the outflow passage 12 and covers the open end edge of the through hole 18 so as to be openable and closable in the attached state. The on-off valve 3 is a plate having elasticity, and is configured using a metal material such as aluminum from the viewpoint of corrosion resistance, elasticity, material cost, and the like. The on-off valve 3 is curved with a curvature along the outer peripheral wall 130 as viewed from the axial direction h.

  Further, the on-off valve 3 has a bent portion 31 at one end in the longitudinal direction, and is fixed by inserting the bent portion 31 into the groove 195. The bent portion 31 of FIG. 4 functions as a male fitting portion with respect to the groove 195, is formed according to the inner dimension of the groove 195 viewed in the axial direction h, and is press-fitted into the groove 195.

  6 is a perspective view of a weighing device according to an embodiment of the present invention, and FIG. 7 is a perspective view showing an exploded structure of the weighing device of FIG. 6 and 7 is a portion that serves as a mechanism for measuring the flow rate of a fluid (f) such as tap water in an impeller-type water meter, and the inner device described with reference to FIGS. A case 1 and an impeller 4 are included.

  The impeller 4 is accommodated in the measuring chamber 100 of the inner case 1. Since the impeller 4 is a well-known component in this kind of impeller water meter, it will be briefly described below.

  The impeller 4 of FIGS. 6 and 7 is made of synthetic resin, has a main shaft 40, a plurality of blades 41, and a drive side magnet 42, and is disposed in the measuring chamber 100 through the opening (15). Under the fluid pressure of the fluid (f) flowing through the measuring chamber 100, it rotates.

  The main shaft 40 has a cylindrical shape extending in the axial direction h and having an opening at a lower end portion, and a hollow 43 having an open lower end is formed in a core portion of the main shaft 40. The cavity 43 is set to such a length that the bottom surface of the impeller 4 floats from the bottom inner surface of the inner case 1 in a state where the pin tip of the pivot shaft 2 is in contact with the inner part. The impeller 4 is rotatably supported in the upper part of the central portion of the measuring chamber 100 while being supported by the pivot shaft 2.

  The plurality of blades 41 are formed to project from the outer peripheral surface of the main shaft 40 extending in the axial direction h. The plurality of blades 41 have a flat protruding piece shape, and extend straight from the position where the main shaft 40 is equally arranged in the circumferential direction c toward the radial direction d.

  The drive side magnet 42 is attached to the upper end portion of the main shaft 40 and constitutes a magnetic coupling with a driven side magnet in a register box (8) described later.

  FIG. 8 is a partial cross-sectional view of an impeller-type water meter according to an embodiment of the present invention. Moreover, FIG.9 and FIG.10 is a front view which expands and shows a part about the use condition of the impeller-type water meter which concerns on this invention.

  The water meter of FIG. 8 is a so-called double box type tangential flow impeller type water meter, and includes a metering device 5 and a main body case 6. The main body case 6 is a well-known component in this type of impeller-type water meter, and will be briefly described below.

  The main body case 6 includes a partition wall 61, a penetrating part 62, an inflow pipe part 63, an outflow pipe part 64, and a strainer 7. The partition wall 61 divides the internal space of the main body case 6 into an upper side and a lower side when viewed in the height direction h. The penetrating portion 62 opens in the plane of the partition wall 61 and penetrates the partition wall 61 in the height direction h.

  The main body case 6 in FIG. 8 has a structure in which an upper casting case 66 is assembled to the upper end surface of the lower casting case 65. The casting lower case 65 has an inflow pipe portion 63 and an outflow pipe portion 64 extending in opposite directions on the outer peripheral surface of the cylindrical portion with the upper end open. According to this structure, when a water main pipe (indicated by a one-dot chain line) is connected to each of the inflow pipe portion 63 and the outflow pipe portion 64, the fluid f such as tap water passes through the internal space of the main body case 6 from the inflow pipe portion 63. Thus, the water will flow to the outflow pipe portion 64 consistently.

  The inner space of the casting lower case 65 is divided by a partition wall 61 into a lower chamber 601 extending downward from the inflow pipe portion 63 and an upper chamber 602 positioned above the lower chamber 601. The penetrating portion 62 penetrates the partition wall 61 in the height direction h and connects the upper chamber 602 and the lower chamber 601 in a water-permeable manner.

  The inflow pipe portion 63 is formed on the outer surface on the upstream side of the main body case 6 and is continuous with the lower chamber 601. The strainer 7 is installed on the inner surface of the inflow pipe portion 63. The outflow pipe portion 64 extends in a direction opposite to the inflow pipe portion 63 on the outer surface on the downstream side of the main body case 6, and is connected to the upper chamber 602.

  On the other hand, the casting upper case 66 has an opening 67 and a lid 68. The opening 67 opens at the upper end of the upper casting case 66 and communicates with the upper chamber 602. The lid 68 covers the opening 67 so that it can be opened and closed.

  The weighing device 5 is guided from the opening 67 to the main body case 6. The inner case 1 constituting the weighing device 5 is guided from the opening 67 to the penetrating part 62, and the step surface 16 abuts against the opening edge of the penetrating part 62, so that the lower chamber 601 and the upper chamber 602 are separated. The water flow between them is blocked. The impeller (4) is accommodated inside the inner case 1, and the impeller (4) rotates by receiving the pressure of the fluid f flowing in the inner case 1 through the inflow passage 11.

  The weighing device 5 of FIG. 8 includes a register box 8 in addition to the assembly of the inner case 1 and the impeller (4) described with reference to FIG. Since the register box 8 is a well-known component in this kind of impeller-type water meter, it will be briefly described below.

  The register box 8 is assembled over the inner case 1 above the impeller (4). The inside of the register box 8 is a waterproof room, in which a driven magnet, a gear mechanism, an integration instruction mechanism, and the like are accommodated (not shown). The driven magnet is provided at a position facing the driving magnet (42) to form a magnetic coupling, whereby the rotation of the impeller (4) is detected, and the counter indication is displayed on the integration instruction mechanism via the gear mechanism. Is done. Then, the display of the integration display unit can be seen through the glass window of the lid 68.

  For the flow rate measurement process using the impeller-type water meter shown in FIG. 8, a water main (indicated by a one-dot chain line) is connected to the inflow pipe portion 63, and a water pipe (indicated by a one-dot chain line) at the downstream outflow pipe portion 64 When the tap is opened and tap water flows out of the tap, the tap water from which foreign matter has been removed by the strainer 7 is passed from the inflow pipe portion 63 via the lower chamber 601. It flows into the measurement chamber (100). At this time, the fluid f flowing into the measuring chamber (100) rises while swirling inside the measuring chamber (100), flows out from the outflow passage 12 to the upper chamber 602, and is discharged through the outflow pipe portion 64. Here, the impeller (4) rotates around the pivot shaft (2) by the pressure of the fluid f. The rotation of the impeller 4 is transmitted from the drive-side magnet 42 to the driven-side magnet, and the rotation of the driven-side magnet is further transmitted to the integration instruction mechanism via the gear mechanism.

  By the way, as already explained, a water meter has been subjected to a meter difference test based on the specific measuring device certification inspection rules (JIS: B8570-2) of the metering law, and the device difference is within a predetermined flow range. In recent years, there is a need for a high-accuracy water meter that is not only within the test tolerance, but also keeps the instrument error as small as possible. .

  Normally, in this type of water meter, the flow direction of the inflow passage 11 is designed to be substantially tangential to the outer peripheral tip of the impeller 4 so that the rotation efficiency of the impeller 4 is taken into consideration and the flow of water is small. Often endeavors to improve accuracy in a small flow rate range. On the other hand, in order to reduce the instrumental difference in the predetermined flow rate range, it is necessary to realize high accuracy of measurement in a large flow rate region in addition to high accuracy of measurement in a small flow rate region. In particular, the influence of various external effects applied to the rotating impeller 4 such as frictional force and rotational energy increases in proportion to the increase in the flow rate. In short, the impeller 4 tends to rotate more than the actual flow rate due to the influence of the external action in a large flow rate region, and as a result, there arises a problem that the instrumental error increases.

  As a conventional technique for solving the above-described problem, for example, a dam is provided in the inflow passage, and a part of the fluid f is guided to the lower side of the measuring chamber 100 by the dam to thereby eliminate the adverse effect on the impeller 4. There is something to do. However, in that case, in the end, the fluid f is allowed to flow into the measuring chamber 100, and the adverse effect on the impeller 4 caused by the fluid f that has flown in cannot be completely eliminated. It cannot be kept small.

  On the other hand, the inner case of FIGS. 1 to 5, the metering device of FIGS. 6 to 7, and the water meter of FIG. 8 using these are the basic configuration of the inner case 1 for an impeller-type water meter. In addition, the above-described problem can be solved by including the through hole 18 and the on-off valve 3.

  First, in the inner case 1 constituting the impeller-type water meter, the through hole 18 extends from the inner surface of the outflow passage 11 along the axial direction h and opens to the step surface 16. According to this configuration, when the inner case 1 is stored in the main body case 6, a part of the fluid f that has flowed into the main body case 6 can be sent directly to the outflow passage 11 through the through hole 18. In other words, when the through hole 18 functions as a bypass, a part of the fluid f flowing into the main body case 6 can be sent to the outflow path 11 without passing through the measuring chamber 100. . Accordingly, the amount of inflow into the measuring chamber 100 is reduced, and as a result, the adverse effect on the impeller 4 due to the increase in the flow rate is eliminated. Therefore, the measurement accuracy in the large flow rate region can be increased. .

  Further, the inner case 1 has an opening / closing valve 3, and the opening / closing valve 3 is attached to the inner surface of the outflow passage 11, and covers the opening edge of the through hole 18 so as to be opened and closed. According to this configuration, the through hole 18 can be opened and closed as the flow rate increases. Specifically, when a large flow rate of fluid f flows into the main body case 6, as shown in FIG. 9, the end of the on-off valve 3 that closes the opening end of the through hole 18 is passed through the through hole 18. The momentum and pushing pressure (for example, water pressure) of the fluid f are transmitted, and the end portion is pushed up according to the momentum and pushing pressure of the fluid f, thereby opening the through hole 18. As a result, the accuracy of measurement in the large flow rate region is realized by the bypass function of the through hole 18 already described.

  On the other hand, when the fluid f flowing into the main body case 6 is in a small flow rate region less than the large flow rate region, the opening / closing valve 3 is not opened and the open end of the through hole 18 is blocked as shown in FIG. The fluid f that has flowed into the main body case 6 is sent to the outflow passage 11 through the measuring chamber 100 because it remains in the state. As a result, the fluid f that has flowed into the main body case 6 rotates the impeller 4 according to the flow rate in the original route (water passage) that is sent from the outflow passage 11 through the measuring chamber 100 to the outflow passage 11. Will be allowed to. Therefore, measurement accuracy in a small flow rate range is ensured.

  As described above, the inner case 1 constituting the impeller-type water meter can open and close the through hole 18 in accordance with the flow rate, so that the measurement accuracy in a small flow rate region can be increased, It is possible to achieve both high measurement accuracy in the flow rate range and to keep instrumental errors small in both flow rate ranges.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is. For example, in the description of FIGS. 1 to 10, the through-hole 18 and the on-off valve 3 that covers the opening edge of the through-hole 18 so as to be openable / closable can be provided in a plurality of outflow passages 12.

  Further, the on-off valve 3 can be appropriately set so as not to operate in a small flow rate region less than the large flow rate region by adjusting the elasticity by selecting a material or adjusting the insertion distance into the groove 195 or the like.

DESCRIPTION OF SYMBOLS 1 Inner case 10 Base | substrate part 100 Measuring chamber 11 Inflow path 12 Outflow path 130 Upper peripheral wall outer surface 131 Lower peripheral wall outer surface 16 Step surface 18 Through-hole 195 Groove 3 On-off valve 31 Bending part 4 Impeller 5 Measuring device 6 Main body case 601 Lower chamber 602 Upper chamber 61 Bulkhead 62 Penetrating portion h Axial direction of inner case and height direction of main body case d Radial direction

Claims (4)

An impeller-type water meter inner case including a base portion, a metering chamber, an inflow channel, an outflow channel, a through hole, and an on-off valve,
The base portion has a cylindrical shape with a bottom, and has a step surface at an intermediate portion of the outer surface of the peripheral wall viewed in the axial direction, and the outer surface of the peripheral wall above the step surface protrudes in the radial direction from the outer surface of the lower peripheral wall. And
The weighing chamber is a bottomed cylindrical internal space of the base portion,
The inflow path opens to the outer surface of the lower peripheral wall and penetrates the measuring chamber;
The outflow channel opens to the outer surface of the upper peripheral wall and penetrates the measuring chamber.
The through hole extends from the inner surface of the outflow passage along the axial direction, and opens to the step surface.
The on-off valve is attached to the inner surface of the outflow passage, and in an attached state, covers the opening edge of the through-hole so as to be opened and closed,
Furthermore, the outflow path has a groove on the inner surface,
The on-off valve is an elastic plate, has a bent portion at one end in the longitudinal direction, and is fixed by inserting the bent portion into the groove.
Inner case. An inner case according to claim 1,
The step surface is parallel to at least one of the opening or the bottom of the base portion.
Inner case. An impeller-type water meter weighing device including an inner case and an impeller,
The inner case is the one described in claim 1 or 2 ,
The impeller is housed in the weighing chamber,
Weighing device. An impeller-type water meter including a main body case and a metering device,
The main body case has an internal space, a partition wall, and a penetrating portion,
The partition wall divides the internal space into an upper side and a lower side when viewed in the height direction,
The penetrating portion penetrates the partition wall in the height direction,
The weighing device is as described in claim 3 ,
The inner case is guided by the penetrating part, and the stepped surface abuts on an opening edge of the penetrating part.
Water meter.

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