JPS6221941Y2 - - 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 the measuring chamber, which is partially 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 about 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, in this invention, in an axial flow impeller water meter, a step part is formed on the inner peripheral wall of the impeller chamber that houses the impeller, and the inner diameter changes from large to small in the direction of passage of tap water. A feature is that a step is formed at the outer end of the blade of the impeller in accordance with the shape of the step.

First, this invention will be specifically explained based on an embodiment of this invention shown in FIG. In the axial flow impeller type water meter shown in FIG. 2, an impeller chamber 14 is formed within the metering chamber 11, and an impeller 15 is housed within the impeller chamber 14. Inner peripheral wall 1 of the impeller chamber 14
1a, that is, the inner circumferential wall 11a of the metering chamber 11 forming the impeller chamber 14 is formed with a downward step portion 11c whose inner diameter changes from a large diameter D ₁ to a small diameter D ₂ in the direction in which tap water passes. On the other hand, the blade 1 of the impeller 15
Also formed at the outer end of 5b is an upward step 15c whose outer diameter changes from a large diameter d ₁ to a small diameter d ₂ in accordance with the shape of the downward step 11c. The blade twist angle α of the large diameter d ₁ portion is made smaller than the blade twist angle β of the small diameter d ₂ portion. Here, the blade twist angles α and β are the twist angles of the blade 15b with respect to the impeller shaft 15a, respectively.

Next, this invention will be explained in more detail based on another embodiment of the invention shown in FIG. In the axial flow impeller type water meter shown in Fig. 3, the metering chamber 21
is placed on the rectifier 22, and the metering chamber 21 and the rectifier 22 form an impeller chamber 24. At this time,
The inner diameter D ₄ of the inner circumferential wall 21a of the metering chamber 21 is the rectifier 2
Since the inner diameter D ₃ of the inner circumferential wall 22 a of the impeller chamber 24 is larger than the inner diameter D 3 of the inner circumferential wall 22 a of the impeller chamber 24 , an upward step portion 22 b is formed on the inner circumferential wall of the impeller chamber 24 by the rectifier 22 . On the other hand, also at the outer end of the blade 25b of the impeller 25 housed in the impeller chamber 24,
A downward step portion 25c is formed whose outer diameter changes from a small diameter d ₃ to a large diameter d ₄ in accordance with the shape of the upward step portion 22b. The blade twist angle γ of the large diameter d ₄ portion is made smaller than the blade twist angle δ of the small diameter d ₃ portion.

As mentioned above, in the axial flow impeller type water meter according to this invention, a stepped portion whose inner diameter changes in the direction of passage of tap water is formed on the inner circumferential wall of the impeller chamber that houses the impeller, and the stepped portion shape is Since a step is formed on the outer end of the impeller blade in accordance with the flow, the flow of tap water is disturbed, increasing the rotational force of the impeller in a small flow area, and creating resistance in a large flow area, reducing the rotational force of the impeller. It will fall.

[Brief explanation of the drawing]

FIG. 1 is a partial longitudinal sectional view of a conventional axial flow impeller type water meter. FIG. 2 shows an embodiment of this invention, and is a partial vertical sectional view of an axial flow impeller type water meter according to this invention. FIG. 3 shows another embodiment of this invention, and is a partial vertical sectional view of an axial impeller type water meter also according to this invention. 15a... impeller shaft, 15.25... impeller,
14, 24... impeller chamber, 11a, 21a, 22
a...Inner peripheral wall, D ₁ , D ₂ , D ₃ , D ₄ ... Inner diameter, 11
c・22b……stepped portion, d ₁・d ₂・d ₃・d ₄ ……blade outer diameter, 15c・25c……stepped portion, α・β・γ・δ…
...Blade twist angle.

Claims (1)

[Scope of utility model registration request] In an axial flow impeller water meter that rotates the impeller with tap water flowing in from a direction parallel to the impeller axis and measures the flow rate of tap water passing through from the rotation of the impeller, an impeller chamber that houses the impeller. A stepped portion whose inner diameter changes discontinuously in the direction of passage of tap water is formed on the inner circumferential wall of the impeller, and a discontinuous stepped portion is formed at the outer end of the blade of the impeller in accordance with the shape of the stepped portion. Axial flow impeller type water meter.