JPH08105771A - Water meter - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a highly sensitive water meter that suppresses the occurrence of peak instrumental difference and at the same time improves the rotation efficiency of the impeller in the minute flow rate range to reduce the minute instrumental difference. . [Constitution] Outer case 3 having outlets 1 and 2 at both ends
Inside, an upper inner case accommodating an indicating mechanism and a lower inner case 7'having a measuring chamber formed by rotatably supporting an impeller are stored, and water flowing into the outer case 3 is stored in the lower inner case 7 '. In the lower inner case 7'of the lower inner wall of the lower inner case 7 ', in which the rotation of the impeller of the measuring chamber is rotated to transmit the rotation of the impeller to the indicator mechanism to measure and measure the flow rate. Four water inlet passages 12 ′ having an aspect ratio of the rectangular opening on the inner peripheral surface of about 1: 0.6 are provided at positions equidistantly distributed on the circumference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water meter, and more particularly, to a structure of a lower inner case incorporated in a multi-box water meter.

[0002]

2. Description of the Related Art For example, a multi-box water meter generally has a structure as shown in FIGS. As shown in the figure, an upper case 5 having an indicator mechanism 4 and an impeller 6 are rotatably rotatably supported in an outer case 3 (lower case) having an inlet 1 and an outlet 2 at both ends. Then, the lower inner case 7 forming the measuring chamber is stored. The lower inner case 7 is mounted in such a state that it is fitted so as to close the opening hole of the partition wall portion 8 that divides the inflow side and the outflow side of the outer case case 3, and the upper inner case 5 is placed above the lower inner case 7. The inner case 7 is mounted in a fitted state so as to close the upper opening. In the figure, 9 is an outer case [upper case], and 10 is a lid mounted on the upper case to be openable and closable.

A pivot 11 is planted in the center of the bottom of the lower inner case 7, and an impeller 6 made of synthetic resin such as plastic is rotatably supported by the pivot 11 to form a measuring chamber. Normally, eight water inlet passages 12 are formed in the lower circumferential wall of the lower inner case 7 at equal circumferential positions so that water can flow from the inflow side of the outer case 3 into the weighing chamber of the lower inner case 7 [Fig. 8]. Also, the lower inner case 7
In order to let water flow out from the measuring chamber to the outflow side of the outer case 3, the water inlet passages 1 are evenly distributed around the upper peripheral wall of the outer case.
Three or four water discharge passages 13 less than two are formed.

Further, a magnet 14 is mounted on an upper portion of a central shaft pivotally supported by the pivot 11 of the impeller 6, and the magnet 14 drives the indicating mechanism 4 housed in the upper inner case 5 in a non-contact manner. The rotation of the impeller 6 is transmitted to the instruction mechanism 4. Incidentally, the upper inner case 5 and the indicating mechanism 4
A magnetic shield ring 15 is provided between the above and the above.

In this water meter, the water from the inflow port 1 flows in from the water inlet passage 12 in the lower peripheral wall of the lower inner case 7, and the impeller 6 in the metering chamber is rotated according to the inflow amount, It flows out from the water outlet passage 13 in the peripheral wall portion and reaches the outlet 2. The rotation of the impeller 6 is transmitted to the indicator mechanism 4 in the upper inner case 5 connected in a non-contact manner via the magnet 14, and the indicator mechanism 4 indicates the flow rate according to the rotation of the impeller 6. .

[0006]

By the way, for the purpose of dealing with high sensitivity in the water meter, in order to efficiently jet the running water to the outer peripheral tip of the impeller 6, as shown in FIG. The cross-sectional shape of 12 is designed to be a pyramid shape so as to be substantially tangential to the outer peripheral tip of the impeller 6. By appropriately designing the pyramidal shape of the water inlet passage 12, it is possible to suppress the peak instrumental difference generated in the change region on the way from the turbulent flow region to the laminar flow region,
We are trying to realize a highly sensitive water meter.

However, as a requirement for realizing a highly sensitive water meter, it is necessary to consider the rotational efficiency of the impeller 6 in the minute flow rate region in addition to the peak instrument difference, and this point is improved. As a means for achieving this, the applicant has focused on the number of water inlet passages 12 of the lower inner case 7. Regarding the number of the water inlet passages 12, a design of 8 from the past to the present has been adopted in the world and has become a common technical knowledge, but this is due to the conventional practice and is not always appropriate. The current situation is that it is not necessarily a thing.

According to the present invention, it is possible to suppress the occurrence of the peak instrument difference, improve the rotational efficiency of the impeller in the minute flow rate range, reduce the minute instrument difference, and provide a highly sensitive water meter. To aim.

[0009]

As a technical means for achieving the above object, the present invention rotates an upper inner case and an impeller having an indicating mechanism housed in an outer case having an outflow inlet at both ends. The lower inner case, which is freely pivotally supported to form a measuring chamber, is stored, the water flowing into the outer case is caused to flow into the lower inner case, and the impeller in the measuring chamber is rotated to rotate the impeller. In the water meter for transmitting the flow rate to the indicating mechanism to measure and measure the flow rate, 3 to 5 water inlet passages are provided at positions equidistantly distributed on the circumference of the lower peripheral wall portion of the lower inner case.

In the present invention, the four water inlet passages having the aspect ratio of the rectangular openings on the inner peripheral surface of about 1: 0.6 at the circumferentially equidistant positions of the lower peripheral wall of the lower inner case. It is desirable to provide an annular protrusion on the peripheral wall of the intermediate portion of the lower inner case along the circumferential direction thereof, and the outer diameter of the impeller can be made slightly smaller than the inner diameter of the annular protrusion. Is.

[0011]

In the water meter according to the present invention, 3 to 5 water inlet passages are provided at the circumferentially equidistant positions of the lower peripheral wall of the lower inner case,
In particular, if four water inlet passages with an aspect ratio of the rectangular opening on the inner peripheral surface of about 1: 0.6 are provided, the peak device difference that occurs in the change region during the transition from the turbulent flow region to the laminar flow region is suppressed. At the same time, the rotation efficiency of the impeller in the minute flow rate region is improved to reduce the difference in the minute flow unit.

Further, when an annular protrusion is formed on the peripheral wall of the intermediate portion of the lower inner case along the circumferential direction and the outer diameter of the impeller is made slightly smaller than the inner diameter of the annular protrusion, the annular protrusion is While maintaining good sensitivity by exhibiting a damming action and a guiding and guiding action toward the center of the measuring chamber, by reducing the outer diameter of the impeller, the gap between the inner peripheral wall surface of the lower inner case and the impeller is reduced. Since the value is increased, the metering sensitivity in the change region on the way from the turbulent flow region to the laminar flow region is slightly dampened to suppress the occurrence of peak instrumental difference.

[0013]

EXAMPLE An example of a water meter according to the present invention will be described with reference to FIGS. The same or corresponding portions as those in FIGS. 6 to 8 are designated by the same reference numerals, and duplicate description will be omitted.

The feature of the present invention resides in the number of the water inlet passages 12 'provided at the circumferentially equidistant positions of the lower peripheral wall portion of the lower inner case 7'. That is, 3 to 5 water inlet passages 12 ′, which are almost the same number as the 3 or 4 water outlet passages 13 provided on the upper peripheral wall portion of the lower inner case 7 ′, particularly the inner peripheral surface of the lower inner case 7 ′. The four water inlet passages 12 ′ having the aspect ratio of the rectangular opening of about 1: 0.6 are provided. 1 shows four water inlet passages 12 ', FIG. 2 (a) shows a lower inner case 7''provided with three water inlet passages 12'', and FIG. 2 (b) shows five water inlet passages 12''. The lower inner case 7'with 'is shown. In the following embodiments, the four water inlet passages 1 shown in FIG.
The case where 2'is formed will be described.

If the cross-sectional area of the water inlet passage is left unchanged and the number thereof is simply reduced from that of the conventional product [eight water inlet passages 12], the rotation speed of the impeller 6 is significantly increased, and There is a possibility that the maximum flow rate (Qmax) used will be greatly reduced. Therefore, the maximum use flow rate (Qmax) is set equal to or higher than that of the conventional product, and the cross-sectional area thereof is set to be almost double that of the conventional product so that the capacity of the water inlet passage becomes a predetermined value.

In this case, since the instrumental error varies depending on the aspect ratio of the rectangular opening of the water inlet passage 12 ', it is preferable to set the aspect ratio a to b to about 1 to 0.6 as described above (FIG. 3). reference〕. If the length of the opening of the water inlet passage 12 'is 1 and the width thereof is smaller than 0.6, a peak instrument difference is likely to occur in the vicinity of the change region in the transition from the turbulent flow region to the laminar flow region. On the contrary, if the length of the opening is 1 and the width is larger than 0.6, the flatness of the instrumental error tends to be impaired, and both are unsuitable.

Further, in the present invention, as shown in FIG. 4, in the lower inner case 7 ', an intermediate portion located between the lower peripheral wall portion provided with the water inlet passage 12' and the upper peripheral wall portion provided with the water outlet passage 13. An annular protrusion 16 is formed on the peripheral wall portion along the circumferential direction thereof, and the outer diameter of the impeller 6 is made slightly smaller than the inner diameter of the annular protrusion 16.

As a result, when the water flowing from the water inlet passage 12 'of the lower inner case 7'moves to the water outlet passage 13,
The annular projection 16 has a damming function and a guiding and guiding function toward the center of the measuring chamber to maintain good sensitivity, and the outer diameter of the impeller 6 is made small, so that the lower inner case 7 ' Since the gap between the peripheral wall surface and the impeller 6 is made larger than that of the conventional product, the metering sensitivity in the change region on the way from the turbulent flow region to the laminar flow region is slightly dulled to suppress the occurrence of peak instrumental difference.

As shown in FIG. 5, the product a of the present invention has a high sensitivity for the instrumental difference required as a water meter, and at the same time, the flatness of the instrumental error in a large basin is sufficiently ensured. Further, since the water inlet passage 12 'is opened larger than that of the conventional product, even if the outer diameter of the impeller 6 is slightly reduced, the rotational force of the flowing water can sufficiently act on the tip of the impeller 6, so that the disturbance is disturbed. The results showed that the occurrence of peak instrumental difference could be suppressed in the transitional region on the way from the basin to the laminar basin. Further, since the gap between the inner peripheral wall surface of the lower inner case 7'and the impeller 6 is set to be large, the deterioration of the instrumental error due to the laminar flow resistance of the flowing water in the gap is reduced in the fine flow region, which is appropriate. Holds instrumental error.

By the way, the international standard (ISO) is classified into three measuring classes of Class A, B and C according to the flow rate values indicated by Qmin, Qt and Qmax according to the diameter, and from Qmin to Qt. Range is ± 5%, Qt to Q
The range of max is ± 2%, and the maximum allowable error (device error range) is determined so that it becomes a horizontal T-shape. Class C standard products have the smallest Qmin and Qt values and high accuracy and high sensitivity. It corresponds to a water meter. On the other hand, the water meter of the above-mentioned embodiment is a speculative type (impeller type) compound box type water meter equipped with a dry type indicator mechanism using a magnetic coupling, and the type most commonly used with a diameter of 15 mm. In the case of, it was difficult for the conventional product a to clear the ISO class C standard, but with the product a of the present invention, the actual measured value of the instrumental error is sufficient in the instrumental error range of ± 5% required for the flow rate Qmin. It became clear that the standard was cleared.

In this water meter, the lower inner case 7 '
The four inner water passages 12 ′ having an aspect ratio a: b of the rectangular opening of the inner peripheral surface of about 1 to 0.6 are provided at positions equidistantly distributed on the lower peripheral wall of the lower inner wall. A turbulent flow region is formed by a synergistic effect of forming an annular protrusion 16 along the circumferential direction on the peripheral wall of the middle part of the case 7 ′ and making the outer diameter of the impeller 6 slightly smaller than the inner diameter of the annular protrusion 16. It is possible to suppress the peak instrumental difference generated in the change region on the way from the to the laminar flow region, and at the same time, improve the rotation efficiency of the impeller 6 in the fine flow amount region to reduce the microfluidic device difference.

[0022]

According to the present invention, the aspect ratio of 3 to 5 water inlet passages, particularly the rectangular opening portion on the inner peripheral surface, is approximately 1 to 0 at the circumferentially equidistant positions of the lower peripheral wall portion of the lower inner case. 4 with .6
By providing the individual water inlet passages, it is possible to suppress the peak instrumental difference in the change region on the way to the transition from the turbulent flow region to the laminar flow region, and also to reduce the fine water flow instrument difference in the minute flow amount region, which is highly sensitive A water meter can be easily realized. Further, since the mold structure is simpler than that of the conventional product, the accuracy can be improved and the cost can be reduced. Furthermore, by forming an annular protrusion along the circumferential direction on the peripheral wall of the middle portion of the lower inner case and making the outer diameter of the impeller slightly smaller than the inner diameter of the annular protrusion, the sensitivity of the water meter is further improved. It can be further promoted.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a lower inner case for explaining an embodiment of a water meter according to the present invention.

2A is a sectional view showing a lower inner case having three water inlet passages, and FIG. 2B is a sectional view showing a lower inner case having five water inlet passages.

FIG. 3 is a perspective view showing the lower inner case of FIG.

FIG. 4 is a front view including a partial cross-section showing a lower inner case and an upper inner case in which an annular protrusion is formed on an intermediate peripheral wall portion.

FIG. 5 is a device difference characteristic diagram comparing the present invention product and the conventional product

FIG. 6 is a front view including a partial cross-section showing a specific structural example of a multi-box water meter.

FIG. 7 is an exploded perspective view showing components including an upper inner case, a lower inner case, an impeller, and an indicating mechanism.

FIG. 8 is a sectional view showing a lower inner case used in a conventional water meter.

[Explanation of symbols]

 1 Inlet 2 Outlet 3 Outer case 4 Indication mechanism 5 Upper inner case 6 Impeller 7'Lower inner case 12 'Water inlet passage 16 Annular protrusion

Claims (3)

[Claims] 1. An outer box containing an indicator mechanism and an inner case having a metering chamber formed by rotatably supporting an impeller in an outer box case having outlets and outlets at both ends. In the water meter that causes the water that has flowed into the case to flow into the lower inner case and rotates the impeller of the measuring chamber to transmit the rotation of the impeller to the indicator mechanism to measure and measure the flow rate. A water meter, characterized in that three to five water inlet passages are provided at evenly distributed positions on the lower peripheral wall of the inner case. 2. Four water inlet passages having an aspect ratio of a rectangular opening on the inner peripheral surface of about 1: 0.6 are provided at equal circumferential positions of a lower peripheral wall portion of the lower inner case. The water meter according to claim 1, wherein 3. An annular protrusion is formed on the peripheral wall of the intermediate portion of the lower inner case along the circumferential direction thereof, and the outer diameter of the impeller is made slightly smaller than the inner diameter of the annular protrusion. Item 1. A water meter according to item 1 or 2.