JP5454982B2 - Vertical water meter - Google Patents

Description

  The present invention relates to a vertical water meter in which a rectifier is arranged on the lower coaxial side of an impeller, a fluid flows from the rectifier to the impeller side, and a flow rate is measured based on rotation of the impeller.

  As a rectifier provided in a conventional vertical water meter, a cylindrical wall that guides fluid to the impeller, a central rectifier that is disposed at the center of the cylindrical wall and supports the impeller, and a cylinder from the central rectifier to the cylinder There are known ones including a plurality of rectifying walls extending radially toward a wall (see, for example, Patent Document 1).

JP 2006-29795 A ([0029], FIG. 4)

  By the way, for water meters, the instrumental difference test is conducted based on the specific measuring instrument verification inspection rules (cited in JIS B 8570-2: 2005) of the Measurement Law, and the instrumental error is within the specified flow rate range. The standard for success is not exceeding. However, in recent years, there has been a demand for the development of a high-precision vertical water meter that not only exceeds the test tolerance but also reduces the instrumental error.

  This invention is made | formed in view of the said situation, and it aims at provision of the vertical water meter which can improve a measurement precision conventionally.

The vertical water meter according to the invention of claim 1 is provided with a rectifier formed by radially dividing the inside of a cylindrical wall on the lower coaxial side of the impeller, and from a horizontal inlet to a lower surface opening of the rectifier. In a vertical water meter in which the fluid flowing into the introduction path from the inlet passes through the rectifier and the impeller in this order and is discharged from the outlet, the rectifier has a cylindrical wall. Outwardly located on the opposite side of the inlet and projecting horizontally from the lower end of the cylindrical wall toward the center of the cylindrical wall and covering a part of the fluid passage area formed inside the cylindrical wall from below It is characterized in that a restriction wall is provided.

The invention of claim 2 is the vertical water meter according to claim 1, inward regulating wall is toward the both sides along the circumferential direction of the cylindrical wall from the farthest position relative to the inlet of the cylindrical wall It is characterized in that it is formed so that the amount of protrusion to the center of the cylindrical wall becomes gradually smaller.

A third aspect of the present invention, the vertical water meter according to claim 1, inward regulating wall is toward the both sides along the circumferential direction of the cylindrical wall from the farthest position relative to the inlet of the cylindrical wall It is characterized in that it is formed so that the amount of protrusion to the center of the cylindrical wall decreases stepwise.

[Invention of Claim 1 ]
According to the invention of claim 1 , the measurement accuracy can be improved as compared with the conventional one.

[Inventions of Claims 2 and 3 ]
As in the invention of claim 2 , the inward regulating wall has a continuous amount of protrusion toward the center of the cylindrical wall from the position farthest from the inlet of the cylindrical wall toward both sides along the circumferential direction of the cylindrical wall. Then, it is effective to form it so that it gradually becomes smaller. Further, as in the invention of claim 3 , the inward regulating wall extends from the position farthest from the inlet of the cylindrical wall toward both sides along the circumferential direction of the cylindrical wall, and extends to the center of the cylindrical wall. May be formed so as to decrease stepwise.

Side sectional view of a water meter according to the first embodiment of the present invention. Perspective view of impeller Rectifier perspective view (A) Side view of rectifier, (B) Bottom view of rectifier The graph which showed the experimental result with respect to an Example (A) Flow velocity distribution diagram in horizontal section of conventional product, (B) Flow velocity distribution diagram in vertical section of conventional product (A) Flow velocity distribution diagram in horizontal section of the implementation product 3 , (B) Flow velocity distribution diagram in vertical section of the implementation product 3 Bottom view of rectifier according to another embodiment (1)

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The water meter 95 of the present invention is a so-called vertical axial flow impeller type water meter, and is formed by assembling a meter body 12 to a meter case 11 attached in the middle of a water pipe.

  In the meter case 11, an inflow port 11A that opens horizontally to the left side in FIG. 1 and an outflow port 11B that opens horizontally to the right side are formed, and a lower chamber 13 (extending downward from the inflow port 11A) Corresponding to the “introduction channel” of the present invention) and an upper room 14 located above the lower room 13. Further, the upper room 14 and the lower room 13 communicate with each other in the vertical direction via the communication port 16. The meter body 12 is inserted and assembled from above into an upper surface opening 15 formed on the upper surface of the upper chamber 14, and the lower end portion of the meter body 12 is joined to the peripheral edge of the communication port 16. In the present embodiment, the diameters of the inlet 11A and the outlet 11B are, for example, 50 mm.

  Now, in the meter body 12, reference numeral 50 denotes a cylindrical housing, which is formed by connecting a pair of cylindrical portions 50A, 50B arranged one above the other with a plurality of ribs 52. The lower cylindrical portion 50B is opened up and down, and the blade 43 of the impeller 40 is accommodated in the lower cylindrical portion 50B, and the rectifier 20 is joined to the lower portion of the lower cylindrical portion 50B. ing.

  1, the water flowing into the meter case 11 in the substantially horizontal direction from the inlet 11A through a water pipe (not shown) flows in the lower chamber 13 in a substantially vertical direction. It changes upward, flows in the order of the rectifier 20 and the lower cylindrical portion 50B, proceeds from the upper surface of the lower cylindrical portion 50B to the upper chamber 14 through the ribs 52, 52, and moves from the upper chamber 14 to the outlet 11B.

  As shown in FIG. 1, a shaft accommodating portion 53 hangs down on the lower surface of the upper cylindrical portion 50A so as to taper toward the center of the lower cylindrical portion 50B. A shaft 41 extending from the impeller 40 is accommodated.

On the other hand, a meter unit 60 is attached to the upper surface of the upper cylindrical portion 50A, and the meter unit 60 counts and displays the integrated flow rate of water that has passed through the water meter 95 in conjunction with the rotation of the impeller 40. Note that an upper lid (not shown) is provided on the upper portion of the meter unit 60, and when the upper lid is opened, an integration display portion (not shown) provided in the meter unit 60 can be seen through the glass window 62.

  In FIG. 2, only the impeller 40 is shown. As shown in the figure, the impeller 40 includes, for example, twelve blades 43 projecting radially from the outer peripheral surface of the cylindrical body 42. When viewed from the upper side, that is, the downstream side in FIG. 2, each blade 43 is twisted in its entirety with the lower edge 43 </ b> B preceding the upper edge 43 </ b> A of each blade 43 in the counterclockwise direction. It has a shape. Thereby, when water pressure is applied to the blade 43 from below the impeller, the impeller 40 rotates so that the lower end edge 43B of the blade 43 precedes. That is, the impeller 40 rotates counterclockwise when viewed from above.

  The shaft 41 of the impeller 40 rises vertically upward from the center of the bottom surface of the cylindrical body 42, and the space between the shaft 41 and the inner surface of the cylindrical body 42 is reinforced by ribs 46.

  As shown in FIG. 1, a hollow with an open bottom end is formed in the core of the shaft 41, and a support pin 21 provided in a rectifier 20 described later is inserted into the cavity, and the tip of the support pin 21 is hollow. It is abutted against a bearing 47 provided in the inner part.

  The upper end portion of the shaft 41 and a gear (not shown) constituting the meter unit 60 (specifically, an integration display portion) are connected by, for example, a magnet coupling (not shown). Is transmitted as the rotation of the gear of the meter unit 60.

  The rectifier 20 includes a central rectifier 22 at the center of the cylindrical wall 27, and, for example, six rectifying walls 70 extend radially from the central rectifier 22 toward the cylindrical wall 27. The structure is divided into two passage regions R1.

  The cylindrical wall 27 is open in the vertical direction, and the inner diameter of the upper surface opening is slightly larger than the inner diameter of the lower surface opening. The central rectifier 22 is disposed at a position near the upper end of the cylindrical wall 27. The central rectifier 22 has a dome shape that is rounded downward and tapered. A support hole penetrating in the vertical direction is formed at the center of the dome, that is, the center of the central rectifier 22, and the shaft core portion 22 </ b> A is fixed to the support hole. A support pin 21 stands vertically from the upper end of the shaft core portion 22A, and the support pin 21 is inserted into the cavity of the shaft 41 as described above to rotatably support the impeller 40. . For example, six ribs 26 extend radially from the shaft core portion 22 </ b> A, and a rectifying wall 70 is formed on an extension line of the ribs 26.

  The plurality of rectifying walls 70 are equally arranged in the circumferential direction of the cylindrical wall 27, and are parallel to the axial direction of the cylindrical wall 27 in the vertical direction. The upper end surface of the rectifying wall 70 is flush with the upper end surfaces of the cylindrical wall 27 and the central rectifying body 22. In addition, the lower end edge of the rectifying wall 70 is inclined so as to gradually go downward from the central rectifying body 22 toward the cylindrical wall 27, and the lower end edge on the cylindrical wall 27 side is more than the lower end portion of the central rectifying body 22. Located on the lower side. Six passing regions R1 surrounded by the adjacent rectifying walls 70, 70, the cylindrical wall 27 and the central rectifying body 22 are formed side by side in the circumferential direction of the rectifier 20 (cylindrical wall 27). Each fluid can pass through.

Now, as shown in FIG. 4B, an inward regulating wall 81 projects from the edge of the lower surface opening of the cylindrical wall 27 in the rectifier 20 in the horizontal direction inside the cylindrical wall 27. The inward regulating walls 81 are provided so as to be unevenly located on the lower side of the lower end portions of the respective rectifying walls 70 and closer to the outlet 11B, and have a so-called crescent shape. Specifically, the inward regulating wall 81 is formed over approximately half the circumference of the cylindrical wall 27 on the outlet 11B side, and the amount of overhang is the largest in the portion closest to the outlet 11B, and the outlet 11B. From the circumferential direction of the cylindrical wall 27 (closer to the inlet 11A) and gradually decreases. Of the six passage regions R1 formed in the rectifier 20, a part of the three passage regions R1 disposed on the side close to the outlet 11B is covered from below by the inward regulating wall 81.

Next, the operation of this embodiment configured as described above will be described.
As shown by the thick arrows in FIG. 1, the water flowing into the lower chamber 13 from the inlet 11 </ b> A of the meter case 11 changes in the direction of the flow in the lower chamber 13 to be substantially vertically upward, inside the rectifier 20. It goes to the impeller 40 through each formed passing region R1. And the impeller 40 receives the water which passed the rectifier 20 by each blade | wing 43, and rotates. The water that has passed through the impeller 40 flows to the side of the meter body 12 from between the ribs 52, 52 of the cylindrical housing 50, and travels to the outlet 11B through the upper chamber 14 of the meter case 11. The rotation of the impeller 40 is transmitted to the meter unit 60 via a magnet coupling (not shown), and the flow rate of water is measured and displayed.

[Example 1]
The present invention to determine the effect of engaging Ru angle limiting wall 81 the following experiment was performed. The experimental procedure is as follows.
First, only a water meter 95 (hereinafter referred to as “implemented product 3 ” as appropriate) having the same structure as that of the first embodiment and an inward regulating wall 81 on the rectifier 20 are not provided. Manufactured a conventional water meter (hereinafter referred to as “conventional product” as appropriate) different from the product 3 .

Next, for each water meter (practical product 3 , conventional product), the test method (JIS B 8570-2: 2005 “7.2 Instrumental difference” specified in the specific measuring instrument certification inspection rules of the Measurement Law) The instrument difference test was conducted in “Test”. That is, water was passed at a preset flow rate, and the measured value (display value of the water meter) at that time was obtained. In this embodiment, the rated maximum flow rate Q3 is set to 40 m3 / h, the limit flow rate Q4 is set to 50 m3 / h, the rated minimum flow rate Q1 is set to 0.4 m3 / h, and the transition flow rate Q2 is set to 0.64 m3 / h.

The instrumental difference of each water meter (implemented product 3 , conventional product) was calculated for each set flow rate, and a graph (instrumental difference curve) was formed as shown in FIG. In this graph, the test tolerance (allowable value of instrumental error) is indicated by a thick line.

Furthermore, the simulation of the state where water was passed at the same flow rate to each water meter (implemented product 3 , conventional product) using analysis software was performed, and the flow velocity distribution in the meter case 11 was analyzed. In addition, in FIG.6 and FIG.7, the flow velocity distribution in the meter case 11 of each water meter is shown by the shading of the color.

[Experimental result]
Comparing the product 3 and the conventional product based on the graph of FIG. 5, in the conventional product, the instrumental error could be within the verification tolerance over the entire range from the rated minimum flow rate Q1 to the limit flow rate Q4. In the flow rate range of 1-50 m3 / h, the instrumental error varied between + 0.7% and -2%, and the linearity of the instrumental error curve was low. This is because the flow of water is concentrated in the passage region R1 on the side close to the outlet 11B of the rectifier 20, and as a result, the flow velocity in each passage region R1 aligned in the circumferential direction of the rectifier 20 as shown in the flow velocity distribution diagram of FIG. It is presumed that the variation occurred and the rotation of the impeller 40 became unstable.

On the other hand, in the implementation product 3, it turned out that the instrumental difference in the range of 1.5-50 m3 / h of flow volume can be restrained smaller than a conventional product. That is, it was found that the linearity of the instrumental difference curve is improved as compared with the conventional product. This is because, as shown in FIG. 7 (B), by which the inner angle limiting wall 81 is provided, guided to the center (center rectifying body 22) side of the water in the passage region R1 near the outlet 11B side is rectifier 20 As a result, as shown in FIG. 7A, it is presumed that the variation in the flow velocity in each passing region R1 is improved and the rotation of the impeller 40 is stabilized.

Therefore, by providing the angle limiting wall 81 among the above, it was found that it is possible to improve over conventional measurement accuracy of water meters 95. Further, according to the configuration of the present embodiment, since the rotation of the impeller 40 is stabilized, it is possible to prevent uneven wear of the bearing 47 against which the support pin 21 abuts and improve durability, and pressure loss. Can be reduced.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

(1) As shown in FIG. 8 , the inward regulating wall 81 projects from the position closest to the outlet 11 </ b> B in the cylindrical wall 27 toward both sides along the circumferential direction of the cylindrical wall 27. You may comprise so that may become small in steps.

(2) through the angle limiting wall 81 constituted by a separate part from the rectifier 20 may be fittable structure to the lower end of the rectifier 20. Thus, diverted conventional rectifier, by an easy change of fitting the inner direction regulating wall 81 to the rectifier, it is possible to improve the measurement accuracy of the water meter.

95 water meter (vertical water meter)
11 Meter case 11A Inlet 11B Outlet 13 Lower room (introduction path)
20 rectifier 27 the cylindrical wall 40 impeller 81 inward regulating wall

Claims (3)

A rectifier that radially divides the inside of the cylindrical wall is provided on the lower coaxial side of the impeller, and an introduction path that communicates from a horizontal inlet to the lower surface opening of the rectifier is provided. In the vertical water meter in which the fluid flowing into the introduction path from the inlet passes through the rectifier and the impeller in order and is discharged from the outlet,
The rectifier is formed on the inner side of the cylindrical wall, which is unevenly distributed on the opposite side to the inlet of the cylindrical wall and projects horizontally from the lower end of the cylindrical wall toward the center of the cylindrical wall. A vertical water meter comprising an inward regulating wall that covers a part of the fluid passage area formed from below. The inward regulating wall gradually and continuously projects toward the center of the cylindrical wall from the position farthest from the inlet of the cylindrical wall toward both sides along the circumferential direction of the cylindrical wall. The vertical water meter according to claim 1, wherein the vertical water meter is formed to be small. The inward regulating wall gradually decreases in the amount of protrusion toward the center of the cylindrical wall from the position farthest from the inlet of the cylindrical wall toward both sides along the circumferential direction of the cylindrical wall. The vertical water meter according to claim 1, wherein the vertical water meter is formed as described above.