JPH051782Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to an axial flow impeller water meter equipped with a rectifier.

(Prior Art) The basic structure of a conventional axial flow impeller water meter is as shown in FIG. 5, for example. That is, in the figure, 1 is a main body, and the main body 1 is provided with an inlet body 2 at one end and an outlet body 3 at the other end. A partition wall 4 that partitions an inflow side and an outflow side is integrally provided in the main body 1, and a communication port 5 is bored in this partition wall 4. A rectifier 7 integrated with the impeller case 6 is provided in the communication port 5. That is, a flange portion 9 is provided on the vessel body 8 of the rectifier 7, and the flange portion 9 is engaged and fixed to the rim of the communication port 5. Further, a rectifier boss 10 is provided concentrically with the axis of the vessel body 8 below, that is, upstream, from approximately the middle part in the vertical direction of the rectifier 7, and a plurality of rectifiers are arranged radially around the outer periphery of the rectifier boss 10. Ribs 11... are integrally provided. Furthermore, a pivot shaft 13 projects perpendicularly from the axis of the rectifying boss 10 with a bush 12 interposed therebetween. And this pivot axis 13
An impeller shaft 14 is rotatably supported on the impeller shaft 14, and an impeller 15 having a plurality of inclined blades is integrally fitted onto the impeller shaft 14. The impeller 15 is adapted to rotate within the impeller case 6. Furthermore, a casing 16 is fitted around the outer periphery of the impeller case 6, and this casing 16 is provided with a plurality of outflow ports 17. Further, a gear case 18 is integrally provided in the upper part of the casing 16, and an integration instruction mechanism 1 that interlocks with the impeller shaft 14 is contained in the gear case 18.
9 is stored. In addition, this integration instruction mechanism 1
9 is a transparent glass 20 provided on the upper part of the main body 1;
It is covered by a cover 21.

Further, a vessel body 8 of the rectifier 7 and a rectifier boss 10
The flow device 22 between the flow chambers 22 is formed to gradually become narrower from the inflow side to the outflow side, and
is formed so that its outer peripheral surface is smooth, and the rectifying rib 11
It is also formed smoothly on both sides.

Therefore, the fluid flowing in from the inlet body 2 enters the impeller case 6 through each flow passage 22 of the rectifier 7, and the impeller 15 is rotated by the fluid pressure. Then, the rotation of the impeller 15 is transmitted to the integration instruction mechanism 19 via the impeller shaft 14,
The fluid flow rate will be integrated and instructed. Further, the fluid that has exited the impeller case 6 flows out from the outlet 17 of the casing 16 toward the outlet body 3 .

(Problems to be Solved by the Invention) However, in the conventional axial impeller type water meter, the rectifying boss 10 and the rectifying rib 11 facing the flow device 22 of the rectifier 7 are formed to be smooth. Therefore, the fluid flowing through the flow path 22 becomes a uniform flow and flows toward the impeller 15. When the fluid flowing through the flow path 22 becomes a uniform flow, the flow velocity and the rotational angular velocity of the impeller 15 are in a proportional relationship when the flow is large, and accurate measurement is possible, but when the flow becomes minute, the impeller 15 cannot follow the flow velocity. , the measurement will be negative than the actual flow rate and cannot be measured accurately. According to experiments by the creator of this device, as shown by curve A in the instrumental error characteristic diagram in Figure 4, the instrumental error becomes -4% at 50 l/h, and as the flow rate becomes even smaller, the minus instrumental error decreases. To increase.

This invention was made with attention to the above-mentioned circumstances, and its purpose is to allow the fluid to act effectively on the impeller even at a minute flow rate, and to maintain a proportional relationship between the flow velocity and the rotational angular velocity of the impeller as much as possible. The present invention aims to provide an axial flow impeller type water meter that can maintain even a minute flow rate and improve instrumental error performance.

[Structure of the idea]

(Means and effects for solving the problem) This invention provides a plurality of diagonal flow generating parts on the inner circumferential wall of the rectifier provided on the inflow side of the impeller case, and the fluid flowing inside the impeller case is connected to the impeller. This is due to the fact that it is configured to work effectively against.

(Embodiment) An embodiment of this invention will be explained below based on FIGS. 1 to 3. Parts that are the same as those of the conventional axial flow impeller type water meter shown in FIG. will be added and the explanation will be omitted.

First, the rectifier 7 will be explained. As shown in FIGS. 1 and 2, there are, for example, seven rectifier ribs 1 between the body 8 of the rectifier 7 and the rectifier boss 10.
1... are provided, and a diagonal flow generating portion 31... is provided in each flow path 22... between these rectifying ribs 11.... Since these mixed flow generating portions 31 have the same structure, one of them will be described as a concave portion 32 formed in the inner circumferential wall of the vessel body 8, the cross section of which is, for example, a groove having an arcuate shape. This concave portion 32 extends in the axial direction of the rectifier 7, and its lower end 33 communicates with the lower end opening 7a of the rectifier 7.
A rectifier 7 is installed at the upper end of the vessel body 8 at approximately the middle in the vertical direction.
A water impingement wall 34 is provided substantially perpendicular to the axis of the water impingement wall 34 . A portion of the tap water flowing through the flow passages 22 from the inflow side to the outflow side flows inside the concave portion 32 and collides with the water collision wall 34 to generate a diagonal flow. . In other words,
The tap water rising along the concave portion 32 hits the water collision wall 3
The flow becomes a diagonal flow near point 4, and progresses toward the inside of the flow path 22 while being obliquely accelerated.

The influence of this phenomenon is particularly noticeable when the flow rate is minute, that is, when the flow velocity in the flow passages 22 is slow and the rotation of the impeller 15 is not proportional to the flow velocity due to mechanical loss or the like. That is, as the tap water accelerated by the diagonal flow acts on the impeller 15, the rotational angular velocity of the impeller 15 approaches the flow velocity even if the fluid flow rate is minute.

In the above-described embodiment, the recess 32 having a circular cross section is provided on the inner circumferential wall of the vessel body 8, but the shape of the recess 32 is not limited to the circular arc groove, but may be a rectangular recess. It has the same effect. moreover,
Even if the concave portion has an enlarged diameter on the entire inner periphery from the lower end opening 7a of the rectifier 7 to approximately the middle portion in the vertical direction of the vessel body 8, the instrumental error performance can be improved compared to the conventional water meter.

Here, to describe the experimental results of this inventor, first, from the lower end opening 7a of the rectifier 7 to the vessel body 8.
When a diagonal flow generating section is provided with an enlarged diameter on the entire inner periphery up to approximately the midpoint in the vertical direction, the instrumental error becomes -4% at 42 l/h as shown by curve B in FIG.

Next, the concave portion 32 consisting of the arcuate groove of the rectifier 7
If a diagonal flow generating section 31 with a cross section is provided, a curve C in the same figure will be obtained. That is, the instrument error is -4% at 32 l/h, and the instrument error performance can be greatly improved compared to the conventional axial flow vane type water meter which does not take any measures to generate mixed flow.

[Effect of idea]

As explained above, according to this invention, even if the flow rate of the fluid flowing through the flow path is minute, it can be made to act effectively on the impeller with a simple configuration in which the rectifier is provided with a mixed flow generating section. As a result,
The proportional relationship between the flow velocity and the rotational angular velocity of the impeller can be maintained down to the minute flow rate range, and the instrumental error performance can be greatly improved as shown by curve C in FIG. 4.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of this invention, with Figure 1 being a longitudinal sectional front view of an axial flow impeller type water meter, Figure 2 being a bottom view of the rectifier, and Figure 3 being a diagonal flow meter. FIG. 4 is an instrumental characteristic characteristic diagram, and FIG. 5 is a vertical front view of a conventional axial flow impeller type water meter. 1... Main body, 4... Partition wall, 5... Communication port, 6...
... Impeller case, 7 ... Rectifier, 31 ... Diagonal flow generation part, 32 ... Concave part, 34 ... Water collision wall.

Claims (1)

[Scope of utility model registration request] A communication port is provided in the partition wall that separates the inflow side and the outflow side of the water meter main body, and a rectifier that rectifies the fluid that flows into the communication port and rotates in response to the fluid pressure of the fluid rectified by the rectifier. In an axial flow impeller type water meter having an impeller case equipped with an impeller, the inner circumferential wall of the rectifier has a lower end communicating with the lower end opening of the rectifier, and an upper end having a substantially perpendicular axis to the axis of the rectifier. An axial flow impeller type water meter, characterized in that a plurality of mixed flow generation parts each consisting of a recessed part having a water impingement wall are provided.