JPS6146414Y2 - - Google Patents

Description

[Detailed explanation of the invention] In this invention, tap water flowing in from a direction parallel to the impeller axis hits the impeller, causing the impeller to rotate according to the flow rate of the tap water, and from that rotation, the 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. In the figure, the reference numeral 1 indicates an impeller storage case whose upper portion is omitted, and the reference numeral 2 indicates a rectifier. The impeller storage case 1 is mounted on a rectifier 2 and supported within a lower case 3, only a portion of which is shown. The impeller storage case 1 has a cylindrical portion 1a, and an impeller chamber 4 is formed within the cylindrical portion 1a. In the impeller chamber 4, the blade portion 5a of the impeller 5 is housed. The blade portion 5a includes a cylindrical central boss portion b,
It consists of a plurality of blades w extending radially from the boss b at a constant twist angle, and an impeller shaft 5b is inserted through the boss b. The impeller shaft 5b is disposed along the center of the cylindrical portion 1a, and the impeller 5 is rotatably supported around the impeller shaft 5b. The aforementioned central boss portion b of the impeller 5
Recesses p and q for thinning are provided in directions parallel to the impeller shaft 5b from the inflow side and the outflow side, respectively. Tap water flowing in from a direction parallel to the impeller shaft 5b hits the blades w of such an impeller 5,
This causes the impeller 5 to rotate in accordance with the flow rate of tap water passing through it. In other words, the tap water flows through the rectifier 2 through arrow A.
The flow enters from the direction, is rectified by the rectifier 2, hits the impeller 5, gives rotation to the impeller 5, and is then discharged from the outlet passage 1b. At this time, the rotation of the impeller 5 is transmitted upward by the impeller shaft 5b, and the flow rate of tap water passing through is displayed on the upper display section. As shown in FIG. 1, in the conventional axial impeller type water meter, an annular recess is not formed in the central boss b of the impeller 5 for purposes other than thinning, and the impeller storage case 1 is provided with an annular recess. A fixing protrusion that fits into the recess is not formed.

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

Therefore, in the above-mentioned axial flow impeller type water meter, this invention forms an annular recess in the central boss part of the impeller in a direction parallel to the impeller axis from the outlet passage side, and fixes the impeller into the annular recess. A feature is that the convex portion is formed to protrude from the impeller storage case.

This invention will be specifically explained below based on an embodiment of this invention shown in FIG.

The axial flow impeller type water meter based on this invention has the following features:
The impeller 15 includes a blade portion 15a and an impeller shaft 15b. The blade portion 15a has a cylindrical central boss portion passing through the impeller shaft 15b at the center, similar to the conventional axial flow impeller type water meter shown in FIG.
b', and a plurality of blades W' extending radially from the boss b' at a constant twist angle. However, unlike the conventional axial flow impeller type water meter shown in Fig. 1, the boss portion b' is large enough to accommodate not only a recess for thinning but also a fixing protrusion s, which will be described later. An annular recess r is formed. Its annular recess r
is formed parallel to the impeller shaft 15b and opens on the outlet side passage 11b side of the impeller storage case 11.
On the inflow side of the boss b', a hollowing recess p' similar to that shown in FIG. A fixing convex portion s is formed so as to protrude into the impeller chamber 14. The fixed convex portion may be formed continuously in an annular shape, or a plurality of convex portions may be arranged in an annular shape. The fixed protrusion s is configured to fit into the annular recess r of the impeller 15 described above. The rest of the structure of the axial flow impeller type water meter according to this invention shown in FIG. 2 is the same as the structure of the conventional axial flow impeller type water meter shown in FIG.

According to this invention, an annular recess is formed in the central boss portion of the impeller, and a fixed protrusion formed on the impeller storage case is inserted into the annular recess, thereby preventing the generation of vortices around the impeller shaft. It is possible to improve the instrumental difference ability. FIG. 3 shows experimental data, curve A and curve B. Curve A
is a flow rate Q (m ³ /h) vs. instrumental error E% curve of a conventional axial impeller type water meter as shown in FIG. Curve B is the flow rate Q (m ³ /h) of the axial flow impeller type water meter according to this invention as shown in Fig. 2.
This is an instrumental error E% curve. As can be seen from Fig. 3, with the axial flow impeller type water meter of this invention, there is almost no change when the flow rate increases, but the accurate lower limit flow rate is improved in the micro flow range, and the starting flow rate is improved. This has the advantage of improving differential performance.
It also has the effect of improving the reproducibility of instrumental errors in the microflow range.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional view of a conventional axial flow impeller type water meter. FIG. 2 is an embodiment of this invention, and shows a partial vertical sectional view of an axial flow impeller type water meter according to this invention. FIG. 3 is experimental data, showing flow rate instrument difference curves for a conventional axial flow impeller type water meter and an axial flow impeller type water meter according to this invention. 15b...impeller shaft, w'...blade, 15...
Impeller, b'...Central boss portion, 11b...Outlet passage, r...Annular recess, s...Fixing protrusion, 11...
Impeller storage case.

Claims (1)

[Scope of utility model registration request] In an axial flow impeller type water meter in which tap water flowing in a direction parallel to the impeller shaft hits the impeller and rotates the impeller, and the flow rate of tap water passing through the impeller is measured from the rotation, the impeller shaft is inserted through the axial flow impeller type water meter. The impeller is provided with a central boss portion from which the plurality of blades extend radially, and the central boss portion is opened on the exit passage side of the boss portion to form an annular recess in a direction parallel to the impeller axis, and the central boss portion is inserted into the annular recess. An axial flow impeller type water meter with a fixed convex part protruding from the impeller storage case.