KR20130053370A - Inner case for impeller type water meter, measurement device for impeller type water meter and impeller type water meter - Google Patents

Abstract

PURPOSE: An inner case for an impeller type water gauge, a measuring device for the impeller type water gauge, and the impeller type water gauge are provided to improve the accuracy of measuring in a small flow rate region and a large flow rate region. CONSTITUTION: An inner case for an impeller type water gauge comprises a body unit(10), a measuring chamber(100), an inflow passage(11), an outflow passage(12), a through-hole(18), and an opening/closing valve(3). The body unit is cylindrical shape with the bottom. The measuring chamber is an internal space of the body unit. The inflow passage is opened in the outer surface of the lower peripheral wall and penetrated through the measuring chamber. The outflow passage is opened in the outer surface of the upper peripheral wall and penetrated through the measuring chamber. The through-hole is stretched in an axial direction from the inner surface of the outflow passage. The opening/closing valve is mounted in the inner surface of the outflow passage and covers an edge portion of an opening of the through-hole to be opened/closed.

Description

Inner case for impeller type water meter, metering device for impeller type water meter and impeller type water meter {INNER CASE FOR IMPELLER TYPE WATER METER, MEASUREMENT DEVICE FOR IMPELLER TYPE WATER METER AND IMPELLER TYPE WATER METER}

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

About this kind of water meter, for example, Unexamined-Japanese-Patent No. 2010-243442 is known. The water meter described in JP 2010-243442A is a so-called tangential tangential flow impeller type water meter, and the tap water introduced into the main body case is connected to the inflow path under the inner case. After passing through the metering chamber and turning up the impeller while rotating the impeller, it is discharged through the outflow path above the inner case. The rotation speed of the impeller is transmitted to the display mechanism by magnetic coupling between the magnet mounted on the main shaft of the impeller and the magnet gear in the register box facing the impeller.

By the way, about a water meter, a meter error test is performed based on the specific meter test inspection rule (JIS: B8570-2) of the metering method, and it is passed that a meter error exists in a test tolerance in a predetermined flow range. In addition, in recent years, a high-precision water meter that not only is within the tolerance of the inspection but also suppresses the instrument error as small as possible is required.

Conventionally, this type of water meter is designed so that the inflow path penetrates substantially in the tangential direction to the outer periphery of the impeller, and improves the rotational efficiency of the impeller, such as high accuracy of weighing accuracy in a small flow rate region. I often try to paint. On the other hand, in order to reduce the instrument error seen in the predetermined flow rate range, in addition to the high precision of the weighing accuracy in the low flow rate region, the high precision of the weighing accuracy in the large flow rate region must be realized. In particular, the influence of various external actions added to the impeller during rotation, such as frictional force and rotational energy, becomes large in proportion to the increase in flow rate. In short, the impeller tends to rotate beyond the actual flow rate under the influence of the external action in the large flow rate region, and as a result, there arises a problem that the meter error is enlarged.

In the invention described in JP 2010-243442A, the above problem cannot be solved. For example, the water meter described in JP 2010-243442 A provides an embankment in the inflow path and guides a part of the tap water to the lower side of the metering chamber, thereby eliminating the adverse influence applied to the impeller with the increase in the flow rate. I would like to.

However, in the invention described in Japanese Unexamined Patent Publication No. 2010-243442, after all, tap water is allowed to flow into the metering chamber, the adverse effect on the impeller caused by the tap water introduced cannot be completely eliminated, and therefore, The instrument error cannot be suppressed small.

An object of the present invention is to provide an inner case for an impeller-type water meter, a metering device for an impeller-type water meter, and an impeller-type water meter capable of reducing the instrument error.

Another object of the present invention is an impeller-type water meter inner case and an impeller-type water meter capable of achieving both high precision of weighing accuracy in a low flow rate region and high precision of weighing accuracy in a large flow rate region. An apparatus and an impeller-type water meter are provided.

MEANS TO SOLVE THE PROBLEM In order to solve the above-mentioned subject, the inner case which concerns on this invention is used for an impeller water meter, and includes a gas part, a metering chamber, an inflow path, and an outflow path. The base part has a bottomed cylindrical shape, and has a stepped surface in the middle portion of the outer wall of the circumferential wall seen in the axial direction, and the outer circumferential wall of the upper side projects from the stepped surface in the outer diameter direction than the outer circumferential wall of the lower side. The measurement chamber is a cylindrical internal space with a bottom of the gas unit. The inflow path opens on the outer peripheral wall of the lower side and penetrates through the metering chamber. The outflow path opens on the outer peripheral wall of the upper side and penetrates into the metering chamber.

The present invention is characterized in that it includes a through hole and an opening / closing valve in addition to the basic configuration of the inner case for the impeller water meter. That is, the through hole constituting the inner case according to the present invention extends along the axial direction from the inner surface of the outflow passage and is open to the step surface. According to this configuration, when the inner case is stored in the main body case of the water meter, a part of the tap water introduced into the main body case can be sent directly through the through hole to the outflow passage. In other words, the through hole functions as a bypass, so that a part of the tap water introduced into the main body case can be sent to the outflow path without passing through the metering chamber of the inner case.

The opening / closing valve is attached to the inner surface of the outflow path, and covers the open end edge of the through hole so as to be openable and closed. According to this structure, it becomes possible to open and close a through hole with the increase of flow volume. Specifically, when a large amount of tap water flows into the main body case, the moment of tap water, the pressure (for example, water pressure), etc., are passed through the through hole to the end of the on-off valve blocking the opening end of the through hole. The through hole is opened by pushing the end portion in accordance with the force or pressing pressure of the tap water. As a result, by the bypass function of the through-hole described above, part of the tap water introduced into the main body case is sent to the outflow passage without passing through the metering chamber of the inner case.

On the other hand, when a small amount of tap water flows into the main body case, the opening / closing valve is not opened and the opening end of the through hole is closed, so that the tap water introduced into the main body case passes the metering chamber of the inner case. It will be sent to the spillway.

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 an internal space, a partition, and a penetration part. The partition partitions the internal space into the upper side and the lower side in the height direction. The penetrating portion penetrates through the partition wall in the height direction and connects the upper side and the lower side of the internal space in a water flow manner.

An impeller is accommodated in the measurement chamber of the said inner case, and comprises the measuring apparatus of a water meter. The inner case blocks the water flow between the upper side and the lower side of the inner space by pressing the stepped surface against the edge of the opening end of the penetrating portion.

The inner case constituting the impeller-type water meter according to the present invention has one of the features in that, in addition to the basic configuration of the inner case of this kind, a through hole and an opening / closing valve are included as described above. According to this configuration, when a large amount of tap water flows into the main body case, the on / off valve is opened so that a part of the tap water introduced into the main body case does not pass through the metering chamber of the inner case by the bypass function of the through hole. It will be sent to the spillway. That is, since the inflow into the metering chamber in the large flow rate region is reduced, as a result, the adverse effect on the impeller accompanying the increase in the flow rate is eliminated, so that high precision of the weighing accuracy in the large flow rate region can be realized. .

By setting the opening / closing valve in a low flow rate region below the large flow rate region, for example, when a small amount of tap water flows into the main body case, the opening / closing valve is not opened and one end of the through hole is closed. It is in a state. As a result, the tap water flowing into the main body case rotates the impeller according to the flow rate in the original route (passage path) which is sent to the outflow path after passing through the metering chamber of the inner case.

As described above, according to the present invention, it is possible to open and close the through hole as the flow rate increases or decreases, so that the accuracy of the measurement accuracy in the low flow rate region and the accuracy of the measurement accuracy in the large flow rate region are increased. It is possible to provide an inner case for an impeller-type water meter, a metering device for an impeller-type water meter, and an impeller-type water meter which are compatible with each other.

As described above, according to the present invention, the following effects can be obtained.

(1) An inner case for an impeller-type water meter, a metering device for an impeller-type water meter, and an impeller-type water meter can be provided that can reduce the instrument error small.

(2) Inner case for impeller-type water meter, metering apparatus for impeller-type water meter which can attain both high precision of weighing accuracy in low flow rate area and high precision of weighing precision in large flow rate area, and impeller Drinking water meters can be provided.

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

1 is a partial sectional view of an inner case for an impeller water meter according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1.
3 is a cross-sectional view taken along line 3-3 of FIG. 1.
4 is a partially enlarged view of a portion of the inner case of FIG. 1 omitted.
FIG. 5 is a perspective view showing the open / close valve of FIG. 4 taken out. FIG.
6 is a perspective view of a metering device according to an embodiment of the present invention.
FIG. 7 is a perspective view showing an exploded structure of the metering apparatus of FIG. 6. FIG.
8 is a partial cross-sectional view of an impeller water meter according to the embodiment of the present invention.
9 is an enlarged front view showing a part of the use state of the impeller water meter according to the present invention with a part omitted.
10 is an enlarged front view showing a part of the use state of the impeller water meter according to the present invention with a part omitted.

In FIG. 1-10, the same code | symbol shall represent the same or corresponding part. In addition, in description of FIGS. 1-10, since the axial direction of an inner case and the height direction of the main body case 6 correspond, respectively, they represent all by the code | symbol h.

The inner case of FIG. 1 is used for a so-called tangential tangential flow impeller type water meter, and includes a gas unit 10, a metering chamber 100, an inflow passage 11, an outflow passage 12, and a pivot. It includes the axis (2).

The base part 10 is a cylindrical body with a bottom bottom molded using a synthetic resin material, and has a circumferential wall 13, a bottom part 14, and an opening 15. The opening part 15 is open to the opposite side to the bottom part 14 in the axial direction h.

The base part 10 has a change part which an outer dimension increases (or decreases) in the middle of the outer surface of the circumferential wall 13 seen in the axial direction h, and the step surface according to the dimensional difference g1 in the same change part. 16 is formed. In other words, the circumferential wall 13 has the upper circumferential wall outer surface 130 protruding from the step surface 16 in the radial direction d than the lower circumferential wall outer surface 131.

The stepped surface 16 has one end (outer end) of the outer wall 130 of the circumferential wall as viewed in the radial direction d, and the other end of the upper end of the outer wall 131 of the circumferential wall (131). Iii)) and is parallel to the outer surface of the opening 15 or the bottom 14. The circumferential wall outer surface 130 and the circumferential wall outer surface 131 of FIG. 1 are coaxial, and the step surface 16 is a ring along the circumferential wall outer surface 131 as viewed from the bottom portion 14. It is shown in shape.

The metering chamber 100 is simply the internal space of the base part 10, is partitioned by the circumferential wall 13 and the bottom part 14, and is opened to the outside through the opening 15.

The inflow path 11 opens in the outer peripheral wall 131 and penetrates through the metering chamber 100. As shown in FIG. 2, in the inner case, the inflow path 11 is formed in the circumferential wall outer surface 131 in each of the several position which was 8 times as many as in the circumferential direction (c). Since the inflow path 11 penetrates the circumferential wall 13 in the direction (approximately tangential direction) which obliquely crosses the radial direction d, the inflow path 11 is put in through the inflow path 11 outside the metering chamber 100. Fluid f, such as tap water, or the like, rotates in one direction (for example, counterclockwise) from the lower side of the metering chamber 100 along the penetration direction of the inflow passage 11.

The outflow path 12 opens in the outer peripheral wall 130 and penetrates through the metering chamber 100. As shown in FIG. 3, in the inner case, an outflow path 12 is formed in each of a plurality of positions quadrupled in the circumferential direction c in the circumferential wall outer surface 130. The outflow path 12 penetrates the circumferential wall 13 in the substantially tangential direction similarly to the inflow path 11. With this configuration, the fluid f passed through the inflow passage 11 into the measurement chamber 100 rises in the axial direction h while turning the inside of the measurement chamber 100 counterclockwise, and then flows out ( It is discharged out of the metering chamber 100 through 12).

This will be described 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. At the center of the embossed portion 17, a metal pivot shaft 2 is attached.

In addition to the basic structure of the inner case for the impeller water meter mentioned above, the inner case of FIGS. 1-3 has the through-hole 18 (refer FIG. 3, FIG. 4), and the opening-closing valve 3 (FIG. 4, FIG. There is one feature in that it has more).

The through hole 18 extends along the axial direction h from the inner surface of the outflow path 12 and is open to the step surface 16. More specifically, the outflow path 12 has two inner surfaces 191 and 192 facing in the circumferential direction c, an upper surface 193 facing the axial direction h, and a lower surface 194. (See Figure 4). The lower surface 194 has a surface area s on the outside viewed from the radial direction d (see FIG. 3). The surface area s is a surface area overlapping the step surface 16 when viewed in the axial direction h. The dashed-dotted line of FIG. 3 has shown the outline of the circumferential wall outer surface 131. As shown in FIG.

The through hole 18 has one opening end edge open in the surface region s, penetrates the upper portion of the circumferential wall 13 from the surface region s in the axial direction h, and has a stepped surface ( It is opening in surface of 16). A gap g2 is formed between the edge of the opening end of the through hole 18 in the stepped surface 16 and the lower edge of the outer wall 130 of the circumferential wall. In other words, in the step surface 16, the surface area corresponding to the gap g2 is secured in the outer part of the radial direction d from the edge of the opening end of the through hole 18. As shown in FIG. The gap g2 serves as a mounting table (mounting space) when the inner case is attached to the main body case of the water meter.

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

The opening / closing valve 3 of FIG. 4 and FIG. 5 is attached to the inner surface of the outflow path 12, and covers the opening edge of the through hole 18 so that opening and closing is possible. The open / close valve 3 is a plate body having elasticity and is constructed using a metal material such as aluminum from the viewpoint of corrosion resistance, elasticity, material cost and the like. The open / close valve 3 is curved in curvature along the outer wall 130 on the circumferential wall in the axial direction h.

In addition, the open / close valve 3 has a bent portion 31 at one end in the longitudinal direction, and is fixed by the bent portion 31 entering the groove 195. The bent part 31 of FIG. 4 functions as a male fitting part with respect to the groove | channel 195, is formed in accordance with the internal dimension of the groove | channel 195 seen in the axial direction h, 195).

6 is a perspective view of a metering device according to an embodiment of the present invention, and FIG. 7 is a perspective view showing an exploded structure of the metering device of FIG. 6. The metering apparatus of FIG. 6 and FIG. 7 is a part which becomes a mechanism which measures the flow volume of the fluid f, such as tap water, in an impeller water meter, and the inner case 1 demonstrated with reference to FIGS. And an impeller 4.

The impeller 4 is accommodated in the measurement chamber 100 of the inner case 1. Since the impeller 4 is a well-known component in this kind of impeller water meter, it is demonstrated briefly 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 driving side magnet 42, and passes through the opening 15 to the metering chamber 100. ) Is rotated in response to the fluid pressure of the fluid (f) flowing through the metering chamber (100).

The main shaft 40 is a cylindrical shape extending in the axial direction h and having an opening in the lower end portion, and a cavity 43 of the lower end opening is formed in the shim portion of the main shaft 40. The cavity 43 is set to the length which the bottom surface of the impeller 4 floats from the inner surface of the bottom part of the inner case 1 in the state which the pin tip of the pivot shaft 2 collided inside. In the state where the impeller 4 is supported by the pivot axis | shaft 2, rotation is accommodated freely in the upper part of the center part of the measurement chamber 100. As shown in FIG.

The plurality of blades 41 protrude from the outer circumferential surface of the main shaft 40 that extends in the axial direction h. The plurality of blades 41 form a flat stone piece shape and extend straight from the position in which the main shaft 40 is seven times larger in the circumferential direction c toward the radial direction d.

The drive side magnet 42 is attached to the upper end of the main shaft 40, and forms the magnetic coupling with the driven side magnet in the register box 8 mentioned later.

8 is a partial cross-sectional view of an impeller water meter according to an embodiment of the present invention. 9 and 10 are enlarged front views showing a part of the use state of the impeller water meter according to the present invention.

The water meter of FIG. 8 is a so-called double tangential flow impeller type water meter, and includes a metering device 5 and a main body case 6. Since the main body case 6 is a well-known component in this kind of impeller type water meter, it demonstrates briefly below.

The main body case 6 has a partition 61, a through part 62, an inflow pipe part 63, an outflow pipe part 64, and a strainer 7. The partition 61 partitions the internal space of the main body case 6 into the upper side and the lower side in the height direction h. The penetrating part 62 opens in the surface of the partition 61, and penetrates the partition 61 in the height direction h.

The main body case 6 of FIG. 8 has the structure which assembled the casting upper case 66 to the upper end surface of the casting lower case 65. As shown in FIG. In the casting lower case 65, the inflow pipe part 63 and the outflow pipe part 64 extend in the opposite direction in the outer peripheral surface of the cylindrical part of an upper end opening. According to this structure, when the water main pipe (single-dotted line notation) is connected to each of the inflow pipe part 63 and the outflow pipe part 64, the fluid f, such as tap water, flows from the inflow pipe part 63 to the main body case 6. Passing through the internal space of the flow is consistently flowing water (flow water) to the outlet pipe (64).

The casting lower case 65 has an inner space whose lower space 601 extends downwardly from the inflow pipe portion 63 by the partition wall 61 and an upper chamber 602 located above the lower chamber 601. Divided by). 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 through water.

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

On the other hand, the cast upper case 66 has an opening 67 and a lid 68. The opening port 67 opens to the upper end of the cast upper case 66 and passes through the upper chamber 602. Lid 68 covers opening opening 67 so that opening and closing is possible.

The metering apparatus 5 is guided to the main body case 6 from the opening opening 67. The inner case 1 constituting the metering device 5 is guided from the opening 67 to the penetrating portion 62, and the stepped surface 16 strikes the edge of the opening end of the penetrating portion 62. The flow of water between the lower chamber 601 and the upper chamber 602 is blocked. An impeller 4 is accommodated in the inner case 1, and the impeller 4 rotates in response to the pressure of the fluid f flowing in the inner case 1 through the inflow passage 11.

The metering apparatus 5 of FIG. 8 adds to the assembly of the inner case 1 described with reference to FIG. 7 and the impeller 4, and further includes a register box 8. Since the register box 8 is a well-known component in this kind of impeller water meter, it is demonstrated briefly below.

The register box 8 is assembled with the inner case 1 overlapping with the impeller 4. The inside of the register box 8 is a watertight chamber, in which a driven magnet, a gear mechanism, an integration indicator, and the like are housed (not shown). The driven magnet is provided at a position opposed to the drive magnet 42 and constitutes a magnetic coupling, whereby the rotation of the impeller 4 is detected and counter displayed on the integration indicator mechanism via the gear mechanism. And the display of the integration display unit can be seen through the glass window of the lid 68.

About the flow volume measurement process using the impeller type water meter shown in FIG. 8, the water main pipe (single-dotted line notation) is connected to the inflow pipe part 63, and the water supply pipe (single-dotted line notation) is connected to the outflow pipe part 64 of the downstream side. When the tap water is connected to the faucet or the like through the tap, the tap water is discharged from the tap by tapping the tap water. Inflow. At this time, the fluid f introduced into the metering chamber 100 rises while swirling inside the metering chamber 100, flows out from the outflow passage 12 to the upper chamber 602, and is discharged through the outflow pipe section 64. . Here, by the pressure of the fluid f, the impeller 4 rotates centering on the pivot shaft 2. The rotation of the impeller 4 is transmitted from the drive side magnet 42 to the driven magnet, and furthermore, the rotation of the driven side magnet is transmitted to the integration indicator mechanism via the gear mechanism.

By the way, although already demonstrated, the meter error test is performed on the water meter based on the specific meter test inspection rule (JIS: B8570-2) of the metering method, and it exists that a meter error exists in a test tolerance in the predetermined flow range. In addition, in recent years, a high-precision water meter is required that not only lies within the calibration tolerance but also suppresses the instrument error as small as possible.

Usually, in this kind of water meter, the flow direction of the water in consideration of the rotational efficiency of the impeller 4 is designed such that the penetration direction of the inflow path 11 is substantially tangential to the outer peripheral end of the impeller 4. It is often hard to make high precision in low water volume area. On the other hand, in order to reduce the instrument error seen in the predetermined flow rate range, in addition to the high precision of the weighing accuracy in the low flow rate region, the high precision of the weighing accuracy in the large flow rate region must be realized. In particular, the influence of various external actions applied to the impeller 4 during rotation, such as frictional force and rotational energy, becomes large in proportion to the increase in the flow rate. In short, the impeller 4 tends to rotate beyond the actual flow rate under the influence of the external action in the large flow rate region, resulting in a problem that the instrument error is enlarged.

As a conventional technique for solving the above-mentioned problems, for example, the bad influence on the impeller 4 is eliminated by having a weir in the inflow path and guiding a part of the fluid f to the lower side of the metering chamber 100 by the weir. There is something to do. In that case, however, eventually, the flow of fluid f into the metering chamber 100 is allowed, and the adverse effects on the impeller 4 generated by the flow fluid f cannot be completely eliminated, and thus the meter The error cannot be suppressed small.

On the other hand, the inner case of FIGS. 1-5, the metering apparatus of FIG. 6-7, and the water meter of FIG. 8 using these penetrate in addition to the basic structure of the inner case 1 for impeller water meters. By including the hole 18 and the opening / closing valve 3, the above-mentioned problem can be solved.

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 12 along the axial direction h, and opens to the step surface 16. . According to this structure, when the inner case 1 is accommodated in the main body case 6, a part of the fluid f which flowed in the main body case 6 passes through the through-hole 18 directly, and the outflow path 12 It becomes possible to send. In other words, the through hole 18 functions as a bypass, so that a part of the fluid f introduced into the main body case 6 can be sent to the outflow passage 12 without passing through the metering chamber 100. Done. Therefore, the inflow amount into the metering chamber 100 is reduced, and as a result, since the adverse effect to the impeller 4 accompanying the increase of the flow volume is eliminated, high precision of the metering precision in a large flow area can be implement | achieved.

In addition, the inner case 1 has an opening / closing valve 3, and the opening / closing valve 3 is mounted on the inner surface of the outflow passage 12, and the open end edge of the through hole 18 is mounted in a mounted state. I cover it so that I can open and close it. According to this structure, it becomes possible to open and close the through hole 18 with the increase of flow volume. Specifically, when a large flow rate fluid f flows into the main body case 6, as shown in FIG. 9, an end of the on-off valve 3 blocking the open end of the through hole 18 is penetrated. Passing through the hole 18, the force of the fluid f, the pressing pressure (for example, hydraulic pressure), etc. are transmitted, and the said end part is pushed up according to the moment of the fluid f, or the pressing pressure, and the through hole 18 is carried out. ) Is opened. As a result, the above-described bypass function of the through hole 18 realizes high precision of the measurement accuracy in the large flow rate region.

On the other hand, when the fluid f introduced into the main body case 6 is a low flow rate region less than the large flow rate region, as shown in FIG. 10, the opening / closing valve 3 is not opened, Since the open end is blocked, the fluid f introduced into the main body case 6 is sent to the outflow path 12 through the metering chamber 100. As a result, the fluid f flowed into the main body case 6 passes through the metering chamber 100 from the inflow passage 11 to the outflow passage 12 in the original route (water passage). As a result, the impeller 4 is rotated. Thus, the weighing accuracy in the low flow rate region is secured.

As described above, the inner case 1 constituting the impeller-type water meter can open and close the through hole 18 in accordance with a large flow rate and a low flow rate, so that the precision of weighing accuracy in the small flow rate region is increased. In addition, it is possible to attain both high precision of weighing accuracy in a large flow rate region and to suppress instrument errors in both flow rate regions.

As mentioned above, although the content of this invention was demonstrated concretely with reference to the preferable embodiment, it is clear that those skilled in the art can take various modified forms based on the basic technical idea and teaching of this invention. For example, in the description of FIGS. 1 to 10, the opening and closing valve 3 covering the through hole 18 and the open end edge of the through hole 18 so as to be openable and closed may be provided in a plurality of outflow passages 12. You can also arrange.

In addition, the opening / closing valve 3 can be appropriately set so as not to operate in the low flow rate region below the large flow rate region by adjusting the elasticity in accordance with material selection, or adjusting the distance to the groove 195 or the like.

1: inner case
10: gas part
100: measuring room
11: inflow path
12: outflow
130: outer peripheral wall of the upper side
131: outer peripheral wall of the lower side
16: step surface
18: through hole
195: home
3: on-off valve
31:
4: impeller
5: metering device
6: body case
601: lower chamber
602: upper room
61: bulkhead
62: through part
h: Axial direction of the inner case and height direction of the main body case
d: radial direction

Claims (4)

As an inner case for an impeller water meter including a gas part, a metering chamber, an inflow path, an outflow path, a through hole, and an opening / closing valve,
The base has a bottomed tubular shape and has a stepped surface at an intermediate portion of the outer wall of the peripheral wall seen in the axial direction, and an outer peripheral wall of the upper side protrudes from the stepped surface in a radial direction than the outer peripheral wall of the lower side,
The measurement chamber is a cylindrical internal space having a bottom of the gas unit,
The inflow passage is opened in the outer peripheral wall of the lower side and penetrates the measurement chamber,
The outflow passage is opened on the outer peripheral wall of the upper side and penetrates the metering chamber.
The through hole extends along the axial direction from the inner surface of the outflow passage and is open to the step surface.
The opening / closing valve is mounted on the inner surface of the outflow passage, and covers the open end edge of the through hole so as to be openable and closed,
Furthermore, the outflow passage has a groove on the inner side,
The said opening / closing valve is an inner case which is an elastic plate body, and has a bent part at the end of a longitudinal direction, and is fixed by the said bent part entering a said groove. As the inner case according to claim 1,
The said step surface is an inner case parallel to at least one of the opening part of a base part, or a bottom part. As a metering device for an impeller water meter including an inner case and an impeller,
The inner case is made of the one of claim 1 or 2,
The said impeller is a measurement apparatus accommodated in the said measurement chamber. As an impeller type water meter including a 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 in a height direction.
The through part penetrates the partition wall in a height direction,
The metering device is composed of the one described in claim 3,
The inner case is guided to the penetrating portion, wherein the stepped surface impinges on the edge of the opening end of the penetrating portion.

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