JP3061466B2 - Axial impeller water meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial impeller water meter having an impeller which is installed in the middle of a water pipe and rotates by receiving a fluid pressure of a fluid.

[0002]

2. Description of the Related Art A conventional axial flow impeller water meter has an inlet at one end of a cylindrical case and an outlet at the other end. A flow passage is formed inside the case, and the flow passage is provided with an impeller that rotates by receiving the fluid pressure of the fluid.

[0003] The impeller includes a boss having an impeller shaft,
It consists of a plurality of blades radially arranged at equal intervals to this boss.The blades are inclined with respect to the flow direction of the fluid so as to receive the fluid pressure on their surfaces, and all have the same thickness. Is formed.

In other words, for a 25 mm meter, twelve blades are radially provided around a boss having an impeller shaft, and the thickness of each of these blades is 1.5.
mm.

[0005]

By the way, in water meters, it is required that the instrumental difference is close to ± 0 from a minute flow rate region to a large flow rate region, that is, the flatness and the sensitivity of the instrumental difference performance are good. However, there is a conflicting relationship between the flatness of the instrumental performance and the sensitivity. When the sensitivity is increased, the peak value increases, and the flatness tends to be impaired.

FIG. 5 is an instrumental performance curve diagram, in which twelve blades are provided around a boss having an impeller shaft. This is a case in which the meter is incorporated in a meter and weighed. As shown by a broken line curve, the sensitivity in the minute flow rate region is good, but the peak value increases and the flatness of the instrumental performance is impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to reduce the peak value of an instrumental performance curve and to improve the instrumental performance from a small flow rate range to a large flow rate range. It is an object of the present invention to provide an axial impeller water meter capable of achieving the following.

[0008]

According to the present invention, in order to achieve the above-mentioned object, a first aspect of the present invention is to provide an impeller which rotates by receiving a fluid pressure of a fluid, comprising: a boss having an impeller shaft; A plurality of blades arranged radially at equal intervals and inclined with respect to the flow direction of the fluid, and several of the blades arranged at equal intervals are thicker than other blades. And the downstream end surface of the thick blade is cut. A second aspect of the present invention resides in that the thickness of the thick blade is set to be two to three times that of the other blades.

[0009]

[Function] When, for example, three blades arranged at equal intervals among, for example, 12 blades arranged radially at equal intervals with respect to the boss are made to be 2-3 times thicker than the other blades, the thickness is increased. The distance between the adjacent blade and the adjacent blade, that is, the flow path of the fluid is narrowed, the flow velocity is increased, and the effect is improved in the minute flow rate region. Further, by cutting the downstream end surface of the thick blade, the resistance is reduced, and the rotation speed of the impeller increases accordingly. As a result, the peak value of the instrumental performance curve can be reduced, and the instrumental performance can be improved from a small flow rate range to a large flow rate range.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows a vertical axial impeller water meter, and 1 is a cylindrical case. A base 3 forming an inlet 2 is screwed and fixed to the case 1 at the lower end of the case 1, and an outlet 4 is provided at the upper end of the case 1.

A flow passage 5 is formed inside the case 1,
The flow passage 5 is provided with an impeller 6 described later.
Rectifiers 7 and 8 are fixed to the upstream and downstream sides of the impeller 6 inside the flow passage 5, and a pivot shaft 9 is fixed to a rectifier boss 7 a of the upstream rectifier 7 by a nut 10. The above-mentioned impeller 6 is rotatably supported. Rectifier boss 8a of the downstream rectifier 8
Is provided with a support hole 11 into which the impeller shaft 12 of the impeller 6 is fitted.

A part of the rectifier 7 is provided with a rotating plate 14 which is rotatable about a pivot shaft 13 as a fulcrum.
4 is provided with a pin 15 protruding in the lateral direction on the free end side.

An adjustment shaft 16 rotatable from the outside of the case 1 is provided on a side wall of the case 1 facing the pin 15, and a slit 17 for engaging the pin 15 is provided on the adjustment shaft 16. I have. Then, by turning the adjustment shaft 16, the rotating plate 14 is connected to the pivot shaft 13 via the pin 15.
Can be rotated around the fulcrum, and the flow direction of the fluid toward the impeller 6 can be changed, thereby enabling the instrument difference adjustment.

As shown in FIGS. 1 to 3, the impeller 6 is provided with a boss 18 having an impeller shaft 12 and radially arranged at regular intervals with respect to the boss 18, and is arranged in the direction of fluid flow. And 12 blades 19 inclined.

Of the twelve blades 19, three blades 19a arranged at equal intervals are two times larger than the other nine blades 19.
３3 times thicker. Therefore, the thick blade 1
The distance between the blades 19 and 19 adjacent to the blade 9a is smaller than the distance between the blades 19 and 19 by the thickness increase.
Further, the downstream end surface of the thick blade 19a is cut at an angle of 20 ° to form an inclined surface 20.

Further, the impeller shaft 12 is provided with a fitting hole 21 for fitting to the pivot shaft 9 at the axial center thereof, and a pivot bearing 22 is provided at the bottom of the fitting hole 21. Further, a magnet 23 in which different poles are symmetrically arranged with respect to the axis is embedded at the upper end of the impeller shaft 12.

In the case 1, a protruding portion 24 protruding into the flow passage 5 is provided integrally downstream of the rectifier 8 with the magnetic sensor 25 proximate to the magnet 23. It is buried.

On the other hand, a base 26 is provided on the outside of the case 1, and an indicator case 27 is mounted on the base 26, and a pulse signal from the magnetic sensor 25 is calculated inside the indicator case 27. A control circuit 28 for processing and integrating and displaying is provided, and a battery 29 is provided, and is displayed on the display unit 30.

According to the axial-flow impeller water meter constructed as described above, the fluid flowing from the inlet 2 enters the flow passage 5 and the blades 19 and 19a of the impeller 6 receive the fluid pressure of the fluid. The impeller 6 rotates about the impeller shaft 12 as an axis.

The rotation of the impeller shaft 12 causes the magnet 23 to rotate integrally. Since the magnets 23 are arranged symmetrically with different poles about the rotation axis, the magnetic sensor 25 generates a pulse by the magnetic force. The pulse signal from the magnetic sensor 25 is subjected to arithmetic processing in the control circuit 28 and the display unit 30
Is displayed.

In this case, the impeller 6 has three blades 19a out of the twelve blades 19 radially arranged at regular intervals with respect to the boss 18 and is two to nine more than the other nine blades 19. 3
It is formed twice as thick. Therefore, the thick blade 19a
The distance between the adjacent blades 19 is smaller than the distance between the blades 19 by the thickness increase. Further, the downstream end face of the thick blade 19a is cut at an angle of 20 °.

Therefore, the flow passage between the thick blade 19a and the adjacent blades 19, 19 becomes narrow, the flow velocity increases, and the effect is improved in a minute flow rate region. Furthermore, the thick feather 19
Since the downstream end surface of “a” is cut, the resistance is reduced, and the rotation speed of the impeller 6 increases accordingly. As a result,
As shown by the solid curve in the instrumental performance curve of FIG. 5, the peak value of the instrumental error is reduced by about 4%, and flatness is obtained from a small flow rate range to a large flow rate range. It was possible to improve instrument difference performance.

In the embodiment, three of the twelve blades radially arranged at regular intervals with respect to the boss of the impeller are formed to be two to three times thicker than the other blades. However, it is experimentally confirmed that the same effect can be obtained by arranging four blades at equal intervals, without being limited to 12 blades, and by limiting the number of thick blades to three blades. ing.

[0025]

As described above, according to the present invention, an impeller is composed of a boss having an impeller shaft and a plurality of blades radially arranged at regular intervals with respect to the boss. Some of the blades, which are arranged at equal intervals, are made thicker than the other blades, and the downstream end surface of the thicker blade is cut.

Accordingly, the distance between the thick blade and the adjacent blade, that is, the flow path of the fluid becomes narrow, the flow velocity increases, and the effect is improved in a minute flow rate region. Further, by cutting the downstream end surface of the thick blade, the resistance is reduced, and the rotation speed of the impeller increases accordingly. As a result,
The peak value can be reduced, and the instrumental performance can be improved from a small flow rate range to a large flow rate range.

[Brief description of the drawings]

FIG. 1 is a plan view and a longitudinal sectional side view of an impeller of an axial-flow impeller water meter according to an embodiment of the present invention.

FIG. 2 is a side view of the impeller of the embodiment.

FIG. 3 is a side view showing a thick blade of the impeller of the embodiment.

FIG. 4 is a vertical sectional side view of the axial impeller water meter according to the embodiment.

FIG. 5 is an instrumental performance curve diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 2 ... Inflow port, 4 ... Outflow port, 5 ... Flow path, 6
... impeller, 12 ... impeller axle, 18 ... boss, 19 ... impeller,
19a: Thick blade.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 59-122515 (JP, U) Japanese Utility Model Sho 60-191934 (JP, U) Japanese Utility Model Hei 1-136423 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) G01F 1/10-1/12

Claims (2)

(57) [Claims] An axial flow impeller having a flow passage formed inside a case having an inlet at one end and an outlet at the other end, and an impeller that rotates in response to the fluid pressure of the fluid in the flow passage. In the water meter, the impeller comprises a boss having an impeller shaft, and a plurality of blades radially arranged at equal intervals to the boss and inclined with respect to a fluid flowing direction, An axial-flow impeller-type water meter, characterized in that several of the blades arranged at equal intervals are made thicker than the other blades, and the downstream end surface of the thicker blade is cut. 2. The thickness of the thicker blade is two times that of the other blades.
The axial-flow impeller-type water meter according to claim 1, wherein the water flow rate is up to 3 times.