JPH0323849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an axial impeller type flowmeter used, for example, in water meters, and its purpose is to prevent reverse flow without impairing the instrument error during forward flow. It is possible to improve the condition of the instrument error during backflow, and it is also possible to optimally adjust the instrument error during backflow according to the model, and furthermore, it can be easily applied to small axial flow impeller type flowmeters. An object of the present invention is to provide an axial flow impeller type flowmeter.

To achieve the above object, the axial impeller type flowmeter of the present invention has a plurality of ribs provided at predetermined intervals on the circumference between the upper surface of the impeller housing case and the lower surface of the flow rate display mechanism housing case. The impeller housing case and the flow rate display mechanism housing case are configured separately, one of these housing cases is provided with the rib, and the other housing case is detachably attached to the outer surface of the rib. A plate-like piece is attached to the rib to collide with the backflow liquid and direct the backflow liquid to the inside of the impeller housing case. A step portion is provided to direct the liquid directed by the shaped piece in a direction opposite to the flow direction of the backflow liquid and collide with the backflow liquid entering between the ribs.

The present invention will be described below based on an embodiment shown in FIGS. 1 to 5.

FIG. 1 shows a vertical axial impeller type flowmeter, which has a central part divided into two upper and lower chambers by a partition wall 7c, and a flowmeter connected to the lower chamber at both ends. It comprises a lower case 7 provided with an inlet 7a and an outlet 7b continuous from the upper chamber, a rectifier 1 disposed within the lower case 7, and an impeller 3 disposed within an impeller housing case 2. .

The rectifier 1 includes a boss body having a cylindrical frame-shaped case 1b engaged and fixed in an opening protruding from a partition wall 7c of the lower case 7, and a pivot shaft 12 projecting upward at the center of the case 1b. 1c, and a plurality of guide blades 1a are arranged between the case 1b and the boss body 1c.
... (six in this embodiment) are arranged radially around the pivot shaft 12.

A predetermined distance is ensured between the lower surface portion of the rectifier 1 and the lower case bottom wall portion 7d directly below it,
Liquid A introduced into the lower case 7 from the inlet 7a
is guided below the rectifier 1 and then passed through guide vanes 1a and raised.

An impeller 3 is rotatably provided directly above the rectifier 1, and as shown in FIG. It is housed in a storage case 2 with its lower part rotatably supported by the pivot shaft 12. Therefore, the liquid A introduced below the rectifier 1 and passed through the guide vanes 1a continues to pass through the impeller 3 and flows out to the outlet 7b of the lower case 7. The impeller 3 is made to rotate.

Further, above the impeller housing case 2, a flow rate display mechanism housing case 14 is provided separately from the impeller housing case 2, and the upper part of the impeller 3 is rotatably supported within this housing case 14. At the same time, a flow rate display mechanism is provided that converts the flow rate of liquid A into rotation of the impeller 3 and displays the result. This flow rate display mechanism has the same structure as a known one, so the details are omitted, but the rotation of the impeller 3 is transmitted to the pointer 5 via the gear group 4, and the amount of rotation of the pointer 5 is measured by the scale plate 6. It is constructed so that the flow rate of liquid A can be displayed by reading it at. The scale plate 6
is located facing a window hole opened in the upper surface of the central part of the lower case 7, and is covered by the glass plate 9 of the upper case 10 attached to the opening of the lower case 7. Note that an openable and closable upper lid 11 is attached to the upper case 10, and covers the scale plate 6 and the glass plate 9.

Further, in this embodiment, the guide vane 1
As shown in Fig. 1, a suitable number (three in this example) of a... are divided into upper and lower halves, and the upper body blade portion 1a' is cut in the same manner as the other guide blades 1a. It is fixed to the case 1b and the boss body 1c, and the lower feather portions 1a'' are supported by the case 1b and the boss body 1c so as to be rotatable by a predetermined amount around the pivot shaft 12. That is, each rotating blade is Part 1
a'' is rotated from a position where it overlaps with the upper body blade part 1a' (position in Figure 2) to a position shifted in the circumferential direction with respect to the body blade part 1a' (for example, position in Figure 3). The movable blade portions 1a''...
As shown in the figure, by shifting the guide vanes 1a to a position where they do not overlap, the direction of the liquid flow toward the impeller 3 can be changed by the guide vanes 1a. Therefore, the torque (rotation speed) of the impeller 3 can be changed, and instrumental error adjustment can be performed.

Therefore, the liquid A introduced from the inlet 7a of the lower case 7 to the bottom of the rectifier 1 via the strainer 13
The flow is rectified by rising along the guide vanes 1a of the rectifier 1, hits the impeller 3 in the impeller housing case 2 as a jet, and has a rotation amount corresponding to the flow rate of the liquid A. Rotate the impeller 3 so that The rotation of the impeller 3 rotates the pointer 5 via the gear group 4, and the flow rate of the liquid A is measured by reading the position of the pointer 5 on the scale plate 6.

By the way, in such a flowmeter, the upper circumferential portion of the impeller housing case 2 is provided as shown in FIGS. 4 and 5.
As shown in the figure, a plurality of ribs 15 are integrally provided at predetermined intervals. These ribs 15... have one side inclined at an acute angle from the inner tip to form an inclined surface 15a that improves instrumental error during normal flow, and the other side is also inclined at an even more acute angle to form an inclined surface 15b.
is formed. On the other hand, as shown in the figure, the ribs 15 are made to protrude outward from the outer surface of the lower surface of the flow rate display mechanism storage case 14, collide with the backflow liquid A', and store the backflow liquid A' in the impeller. Case 2
A triangular plate-shaped piece (embodiment) or a rectangular, semicircular plate-shaped piece 17 (not shown) directed toward the inside of the...
are provided in an integrated manner. The inner surface of this plate-shaped piece 17 is as shown in FIG.
By press-fitting into the outer surface of the ribs 15, the ribs 15 are provided in a removable manner. In addition, the plate-like piece 17
... is attached to the outer surface of the rib 15...,
The liquid directed by the plate-like pieces 17 is directed to the base side of the plate-like pieces 17 in a direction opposite to the flow direction of the backflow liquid A', and the backflow liquid enters from between the ribs 15, 15.
A step portion 16 that collides with A' is provided.

With this configuration, when the liquid A is currently in a normal flow state from the inlet 7a of the lower case 7 to the outlet 7b of the lower case 7, the liquid A that has passed through the impeller 3
As shown in FIG. 5, the water flows toward the outlet 7b of the lower case 7 while being rectified in one direction along the inclined surfaces 15a formed on one side of each rib 15. Therefore, due to the rectification effect of the inclined surfaces 15a, it is possible to flatten the instrumental error in the normal flow state, and it is possible to effectively improve the measurement error.

On the other hand, by improving the instrumental error during normal flow, when the flow is reversed from the outflow port 7b of the lower case 7 to the inflow port 7a of the lower case 7, the backflow liquid A' is on the contrary affected by the inclined surface 15a. If too much turning force is applied in the direction along the flow direction, the impeller 3 will be rotated more than necessary, which will worsen the condition of instrumental error during backflow. However, in this case, since the plate-shaped piece 17 and the stepped portion 16... are provided, the backflow liquid A' at the upper part of the figure collides with the plate-shaped piece 17... and then moves to the arrow C by the stepped portion 16... The flow in the direction of the arrow C and the flow in the direction of the arrow B collide with each other to form a vortex state, and the flow of the backflow liquid A' that exerts too much swirling force can be suppressed. On the other hand,
The backflow liquid A' at the bottom of the figure is a flow in the direction of arrow B' whose direction is changed by plate-like pieces 17, and a flow in the direction of arrow B'.
The flow in the B″ direction collides with each other, creating a vortex state.
This can also suppress the swirling flow of the backflow liquid A'. Therefore, no more rotational force than necessary is applied to the impeller 3, and the state of instrumental error during backflow can be effectively improved.

It should be noted that the vertical impeller type flowmeter having the configuration of the above embodiment and the inclined rib 10 shown in FIG.
Comparison experiment with a vertical impeller type flowmeter with 0,
In other words, when we conducted a comparison experiment of instrumental difference characteristics, we found that
The results shown in the graph shown in FIG. 7 were obtained. According to this, with the conventional system, as the flow rate increased, the instrumental error during reverse flow moved toward the positive side, and there was a large gap between the instrumental error during forward flow, but with the system to which the present invention is applied, It was confirmed that even when the flow rate increased, there was no large gap between the reverse flow and the forward flow, and good instrumental error characteristics were obtained both during the reverse flow and the forward flow.

As described above, although the present invention has a very simple configuration, its effects are outstanding, and it can fully meet the international standards for instrumental errors in forward and reverse flows that have recently been required.

Moreover, with the configuration of the present invention, the plate-like piece is removable from the outer surface of the rib, so by appropriately setting the attachment position of the plate-like piece with respect to the outer surface of the rib, the state of instrumental error during backflow can be reduced. It is very convenient because it can be set to the optimal instrument error condition for different models, and it can also be easily applied to small vertical axial flow impeller type flowmeters that have space constraints. .

It should be noted that the present invention is not limited to the configuration of the above embodiment, but for example, as shown in FIG. It can also be applied to things that don't have one. Even with such ribs, if there are structural changes in the structure of the impeller housing case, the structure of the lower case, or other parts, there may be cases where too much rotational force is applied to the impeller during backflow. It is. Also,
In the embodiment described above, the ribs were integrally provided in the impeller housing case, and the plate pieces were integrally provided in the flow rate display mechanism housing case, but of course, the ribs and plate pieces could be integrally provided in the opposite situation. good. In any case,
The present invention is applicable to all axial flow impeller type flowmeters having ribs.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a longitudinal sectional view of a vertical axial impeller flowmeter, Figure 2 being a bottom view of the rectifier, and Figure 3 being the same. FIG. 4 is a front view showing the impeller storage case and the flow rate display mechanism storage case, and FIG. 5 is a cross-sectional view of the main parts taken along the - line in FIG. 1. , Fig. 6 is a sectional view of the main part corresponding to Fig. 5 showing a conventional rib, and Fig. 7 shows the results of a comparative test between the rib to which the present invention is applied and the conventional rib, using measured values and a diagram. , FIG. 8 is a sectional view of a main part corresponding to FIG. 5, showing another embodiment of the present invention. 2... Impeller housing case, 14... Flow rate display mechanism housing case, 15... Rib, 16... Step portion, 17... Plate piece, A'... Backflow liquid.

Claims (1)

[Claims] 1. In an axial impeller flowmeter in which a plurality of ribs are provided at predetermined intervals on the circumference between the upper surface of the impeller storage case and the lower surface of the flow rate display mechanism storage case, the impeller storage case and the flow rate display are provided. The mechanism housing case is configured separately, and one of these housing cases is provided with the rib, and the other side is removably attached to the outer surface of the rib to collide with the backflow liquid, and the backflow liquid is removed by a blade. A plate-like piece is provided to direct the liquid toward the inside of the vehicle storage case, and the liquid directed by the plate-like piece is directed to the base side of the plate when the plate-like piece is attached to the outer surface of the rib. An axial impeller type flowmeter characterized in that it is provided with a stepped portion that is oriented in a direction opposite to the flow direction of the ribs and collides with the backflow liquid that enters from between the ribs.