JPS6221944Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention applies tap water flowing in from a direction parallel to the impeller axis to the impeller, causes the impeller to rotate according to the flow rate of the tap water, and from that rotation, tap water flows into the impeller. This invention relates to an axial flow impeller type water meter that measures passing flow rate.

Conventionally, this type of axial flow impeller type water meter has had a configuration as shown in FIG. 1, for example. The symbol 1 in the figure is a measuring chamber with a part omitted.
What is indicated by 2 is a rectifier. The metering chamber 1 rests on a rectifier 2 and is supported in a lower case 3, only a portion of which is shown. Inside the metering chamber 1, an impeller chamber 4 is formed by providing a circumferential inner wall 1a. and,
An impeller 5 is housed in the impeller chamber 4 and is supported rotatably around an impeller shaft 5a.
The blades 5b of the impeller 5 are marked with an arrow A to the rectifier 2.
Tap water enters from the direction parallel to the impeller shaft 5a and is rectified by the rectifier 2, and hits the metering chamber 1 from a direction parallel to the impeller shaft 5a, causing the impeller 5 to rotate in accordance with the flow rate of the tap water. Then, it exits from the exit passage 1b of the measuring chamber 1. At this time, the rotation of the impeller 5 is transmitted upward by the impeller shaft 5a, and the flow rate of the tap water passing through is displayed on the upper display section.

The purpose of this invention is to improve the instrumental error performance in the above-mentioned axial flow impeller type water meter.

Therefore, the present invention provides an axial flow impeller type water meter with an auxiliary adjustment plate that rotates around an axis perpendicular to the impeller axis downstream of the impeller to adjust the distance from the impeller as appropriate. It is characterized by

The features of the invention will become clearer from the following description of the illustrated embodiment.

FIG. 2 is a partial longitudinal sectional view showing the axial impeller type water meter according to the present invention. In this water meter, an impeller chamber 11 is formed within a metering chamber 10, and an impeller 12 is housed within the impeller chamber 11. Below the impeller chamber 11, there is a rectifier chamber 1 in the rectifier 13.
4 is formed, and a rectifying blade 15 is installed in the rectifying chamber 14. Further, an adjustment plate 16 having approximately the same shape as the rectifying blade is housed in the rectifying chamber 14,
It is rotatably attached to the inner circumferential wall 13a of the rectifier 13 with screws 17. The adjustment plate 16 is used as a variable rectifying blade to increase or decrease the number of rotations of the impeller 12 by changing the angle of the blade (indicated by reference numeral A in the figure) with respect to the flow of tap water and changing the direction of the speed vector.

Further, the inner circumferential wall of the impeller chamber 11, that is, the inner circumferential wall 10 of the metering chamber 10 forming the impeller chamber 11.
An auxiliary adjustment plate 18 is attached to a.
The auxiliary adjustment plate is movably mounted above the impeller 12 near the tap water passage outlet 19 with a mounting screw 20, that is, for example, as shown in FIG. The impeller 12 is moved up and down (indicated by arrows in the figure) along the
The distances l and l' from the upper end surface 12a can be changed as appropriate. As shown in Figure 3B, the auxiliary adjustment plate 18 can be rotated angularly (indicated by the arrow in the figure).
It can also be attached to the inner circumferential wall 10a of the measuring chamber 10.

As described above, in the axial impeller type water meter according to the present invention, in addition to the adjusting plate 16 as a variable rectifying blade in the rectifying chamber 14, there is also a separate inner circumferential wall of the impeller chamber 11 that houses the impeller 12. Auxiliary adjustment plate 1 on 10a
8, the adjustment plate 16 in the rectifier chamber 14 is installed at a different angle with respect to the flow of tap water to make a large instrumental difference adjustment, and then the auxiliary adjustment plate 18 is installed.
This allows fine adjustment of instrumental errors. That is, in a small flow range, the tap water flowing into the impeller chamber 11 hits the auxiliary adjustment plate 18 near the passage outlet 19 and further hits the impeller 12, increasing its rotational force; The adjusting plate 18 actually acts as a resistance, and the rotational force of the impeller 12 decreases. Then, the auxiliary adjustment plate 18 is movably attached to the inner peripheral wall 10a of the impeller chamber 11, and the distances l and l' between the upper end surface 12a of the impeller 12 and the auxiliary adjustment plate 18 are changed as appropriate to adjust the flow of tap water. By making appropriate fine adjustments accordingly, the instrumental error performance can be further improved.

Therefore, FIG. 4 shows experimental data for comparison with the conventional method, and shows curves A, (indicated by broken lines), curve B, and curve C. Curve A is the flow rate Q (m ³ /h) of the conventional axial impeller type water meter mentioned above - instrumental error E
(%) curve. Curve B shows the flow rate of the axial impeller type water meter according to the present invention, in which an auxiliary adjustment plate is provided on the inner peripheral wall of the impeller chamber, and the distance l between the auxiliary adjustment plate and the upper end surface of the impeller is 5 mm. It is a Q (m ³ /h)-instrumental error E (%) curve. Curve C is a curve similar to curve B of the water meter of the present invention in which the distance l between the auxiliary adjustment plate and the upper end surface of the impeller is 3 mm. As is clear from FIG. 4, in the axial flow impeller type water meter according to the present invention, first, the peak values p and p' based on the instrumental error in the large flow of the test are compared to the conventional peak values.
p″ can be lowered from 11% to 8%. Furthermore, the instrumental error between the large test flow and the upper limit of the reference flow rate range, or between the large test flow and the small test flow, can be reduced from the conventional 1.5% to 0.5% or less. This has the advantage that a remarkable flatness of the instrumental difference curve can be obtained.

Furthermore, FIG. 5 shows experimental data for another embodiment of the present invention, which is an axial flow impeller type water meter in which the auxiliary adjustment plate is provided on the inner peripheral wall of the impeller chamber so as to be angularly rotatable as described above. This is due to
Curve A is the median value when the auxiliary adjustment plate is positioned parallel to the impeller blades, that is, the flow rate Q (m ³ /h) - instrumental error E
(%) curves (indicated by broken lines in the figure), and curves B and C represent the flow rate Q when positioned at maximum on the (+) side and (-) side, respectively, centering on the median value.
(m ³ /h) - instrumental error (%) curve is shown. As is clear from FIG. 5, fine adjustment of the instrumental error of 1% is possible, and, like the embodiment shown in FIG. 4, this has the great advantage of significantly increasing the flatness of the entire instrumental error curve.

[Brief explanation of the drawing]

Figure 1 is a partial vertical sectional view of a conventional axial flow impeller type water meter, Figure 2 is a partial vertical sectional view showing the axial flow impeller type water meter according to the present invention, and Figure 3 A and B are auxiliary, respectively. A schematic explanatory diagram showing the state of movement of the mounting position of the adjustment plate, and Fig. 4 are experimental data showing the flow rate-instrument difference between the conventional axial flow impeller type water meter and the axial flow impeller type water meter according to the present invention. Diagram showing the curve, No. 5
The figure is a diagram showing a flow rate-instrumental error curve in another embodiment of the present invention. 10a... Inner peripheral wall of the impeller chamber, 11... Impeller chamber, 12... Impeller, 14... Rectification chamber, 16...
Adjustment plate, 18... Auxiliary adjustment plate.

Claims (1)

[Scope of utility model registration request] In an axial flow impeller water meter that rotates the impeller with tap water flowing in the impeller axial direction and measures the flow rate of tap water passing through from the rotation of the impeller,
An axial flow impeller type water meter comprising an auxiliary adjustment plate that rotates around an axis perpendicular to the impeller axis downstream of the impeller to adjust the distance to the impeller as appropriate.