JPS6237134Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rectifying device in a water meter.

Conventionally, in this type of water meter, as shown in FIG. 1, the state of water flowing through the water passage section 9 formed by the inner wall surface 4a of the rectifier and the outer circumferential surface 4b of the bearing boss is such that when the amount of water is below a certain level, The flow becomes laminar, and above a certain level, the flow becomes turbulent. In the case of turbulent flow, the flow velocity at each part is averaged to show the actual flow rate. However, in the laminar flow state, the flow velocity is slow in the inner wall surface 4a of the rectifier, the outer circumferential surface 4b of the bearing boss, and in the portions close to the water flow surface of the rectifying plate 10 provided radially in the water flow portion 9, and in the portion farther from the surface. It becomes rapid. The metering impeller 5 is therefore rotated by the fastest water in the rapid section, and the meter pointer displays a measured value greater than the actual flow rate. If this is shown in terms of instrumental error performance, it will be in the state shown by performance curve A in Figure 5. At flow rates above a certain level, the flow becomes turbulent and the instrumental error is small, and at flow rates below a certain level, the flow rate becomes higher than the actual flow rate. Produces instrumental error peaks.

Conventionally, as a method of reducing this peak, there is a method in which the flow area is changed in the measuring chamber 2a, but in this case, the performance curve is in the state shown in B in Fig. 5, and there is one problem. In addition to being unsatisfactory, if this area change is too large, it may cause damage due to lack of accuracy when using a small flow.

In view of the above, it is an object of the present invention to propose a device that can further reduce the peak of instrumental error as described above and can accurately measure even in the case of a small flow.
a, the outer peripheral surface 4b of the bearing boss, and the wall surface of the rectifier plate 10. A ring-shaped rod passing through the radial center of the water passage portion is attached to the upper end surface of the rectifier plate 10. It is characterized by being constructed.

Next, an embodiment shown in the drawings in which the present invention is applied to a vertical axial flow impeller water meter will be described.

1 is a meter case, 2 is an inlet, 3 is a strainer, 4 is a rectifier, 5 is a metering impeller, 6 is a metering chamber, 7a is an inlet side chamber, 7b is an outlet side chamber, 8 is a shaft 5a of the metering impeller. A supporting hole 9 is a water passage portion formed by the inner wall surface 4a of the rectifier 4 and an outer peripheral surface 4b of the bearing boss, and 10 is a water passage portion 9 formed radially around the support hole 8 in the water passage portion 9. These are the same as the conventional structure. 11a is a ring-shaped rod that obstructs the flow of water to be measured, and as shown in FIG. 2, the rod is centered on the impeller shaft 5a and has a radius at the center between the inner wall surface 4a of the rectifier and the outer peripheral surface 4b of the bearing boss. The current plate 1 is located along the circumference line, that is, at the center of the water passage section 9 in the radial direction.
It is located at the upper end of 0.

As described above, when the water to be measured flows from the inlet 2 through the strainer 3 into the inflow side chamber 7a, the water to be measured passes through the water passage part 9 in the rectifier 4 and passes through the metering impeller 5. It is rotated and flows out into the outflow side chamber 7b. This causes the metering impeller 5 to rotate,
As is well known, the flow rate is displayed by rotating the metering indicator. At this time, the water to be measured passing through the water passage section 9 is
The flow is rectified by the rectifying plate 10, but when the flow rate exceeds a certain value, the flow becomes turbulent, and the velocity distribution inside the water passage section 9 is close to the average flow velocity except near the wall surface.
When the flow rate is below a certain value, the flow becomes laminar, and the flow velocity near the center of the water passage section 9 is faster than in other parts. However, as in the present invention, by providing the ring-shaped rods 11a and 11b that pass through the center of the water flow section 9 in the radial direction, the flow of the water to be measured passing through the center is obstructed, and the flow rate is lower than that of other water. Even in a laminar region, the velocity distribution approaches that of turbulent flow. As a result of experiments using the water meter of the present invention equipped with this ring-shaped rod material, its performance curve showed the value C in Figure 5, and the peaks observed in the performance curves A and B of the conventional structure were extremely high. It became smaller and the instrumental error decreased. In addition, in this invention,
Since there is no need for a structure that changes the flow area in the metering chamber 2a as in the prior art, there is no lack of accuracy when the flow is small as described above.

As described above, the present invention can significantly reduce the peak of instrumental error seen in conventional structures, and also enables accurate measurement in the case of microflows.Moreover, its structure is simple, making it easy to manufacture. It is easy and inexpensive and is practically effective.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view of the present invention applied to a vertical shaft impeller water meter, Figs. 2 and 3 show two embodiments of the ring-shaped rod, A is a plan view, and B is a plan view. is a sectional view taken along line X-X', and FIG. 4 is a diagram showing an instrumental error performance curve. 4... Rectifier, 4a... Inner wall surface, 4b... Outer peripheral surface of bearing boss, 9... Water passage section, 10... Current plate,
11a, 11b...ring-shaped rods.

Claims (1)

[Scope of utility model registration request] A ring-shaped rod passing through the center of the water passage section in the radial direction is attached to the water passage section 9 formed by the inner wall surface 4a of the flow straightener 4, the outer peripheral surface 4b of the bearing boss, and the wall surface of the flow straightening plate 10. 1. A rectifying device in a water meter, characterized in that it is installed on the upper end surface of a water meter.