JP4363622B2 - Rectifier and impeller flow meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impeller-type flow meter and an impeller-type flow meter for measuring a flow rate based on rotation of the impeller by arranging a rectifier adjacent to the lower surface of the impeller to flow a fluid from the rectifier to the impeller side. It relates to the rectifier provided.
[0002]
[Prior art]
Figure 11 is a conventional impeller flowmeter shown, a rectifier 2 is shown enlarged in FIG. 12 having its impeller flowmeter. As shown in FIG. 11 , in this impeller flow meter, the support pin 7 stands up from the upper surface of the central rectifier 3 provided in the rectifier 2, and the impeller 1 rotates around the support pin 7. . Here, the impeller 1 receives fluid from below and rotates. At this time, the impeller 1 slides upward, and the upper end portion of the impeller 1 is pressed against the upper surface wall 6 to slide. For this reason, in the conventional impeller-type flow meter, as shown in FIG. 12 , the auxiliary rectifying plate 4 is laid on the upper surface of the central rectifying body 3 in the rectifier 2, and the outer rim of the auxiliary rectifying plate 4 is the central rectifying body 3. The fluid pressure to the side of the impeller 1 was reduced (for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-9-145427 (paragraphs [0023] to [0028], FIG. 3)
[0004]
[Problems to be solved by the invention]
By the way, it is considered that the upward slide of the impeller 1 affects the measurement performance. However, the conventional impeller-type flow meter described above cannot satisfy high measurement performance corresponding to the OIML (International Legal Metrology Organization) standard.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an impeller-type flow meter and a rectifier capable of improving measurement accuracy as compared with the related art.
[0006]
[Means for Solving the Problems]
The rectifier according to the invention of claim 1 made to achieve the above object measures the flow rate based on the rotation of an impeller provided with twelve twisted blades radially projecting from the outer peripheral surface of a cylindrical rotating body. A rectifier arranged adjacent to the lower surface of the impeller of the impeller-type flow meter, and a cylinder that guides fluid to the impeller and a central portion of the cylinder that is arranged near the impeller and facing downward. A central rectifying body having a rounded and tapered dome shape and having a support pin for pivotally supporting the impeller on the upper surface, and a cylindrical body protruding radially from the central rectifying body to the side 6 rectifying walls that are sandwiched between them and have a lower edge inclined obliquely downward from the central rectifying body , and two rectifying walls that are 180 degrees apart from each other among the 6 rectifying walls Formed on the four rectifying walls except for the direction of rotation of the impeller Projecting from the lower side located inside the inclined surface and the central flow regulator and the rectifier wall of the inner surface of the cylindrical body baffle wall is to be inclined so as to be thinner toward the end of the impeller side surface facing the And the area of the part through which the fluid passes inside the weir part is A, and the area of the part through which the fluid passes through the opening on the impeller side of the cylinder Is characterized in that the ratio R obtained by R = A / B is 115 to 140% .
[0008]
The invention according to claim 2 is characterized in that, in the rectifier according to claim 1 , the weir portion is a flat ring fitted inside the cylindrical body.
[0010]
According to a third aspect of the present invention, in the rectifier according to the first or second aspect, of the six rectifying walls, the two rectifying walls excluding the four rectifying walls formed with inclined surfaces are arranged on the impeller side. A movable wing is provided at the end, and the movable wing is characterized in that it can be tilted back and forth in the rotational direction of the impeller.
[0011]
An impeller type flow meter according to the invention of claim 4 is characterized in that the rectifier according to any one of claims 1 to 3 is provided.
[Action and effect of the invention]
If the impeller-type flow meter or rectifier of the present invention is used, the fluid pressure to the impeller is moderately suppressed by the weir part, and the measurement accuracy can be improved as compared with the conventional impeller-type flow meter. Specifically, when the area of the portion through which the fluid passes inside the weir is A and the area of the portion through which the fluid passes through the opening on the impeller side is B, R = A The ratio R calculated by / B is preferably 115 to 140% . Further, of the six rectifying walls provided in the rectifier, the four rectifying walls excluding the two rectifying walls at positions 180 degrees apart from each other face the direction opposite to the rotation direction of the impeller on the impeller side. The measurement accuracy can be further improved by forming an inclined surface that is inclined so that the rectifying wall becomes thinner toward the end of the film. Further, by configuring the weir portion with a flat ring fitted inside the cylinder, the problem can be solved by an easy design change of fitting the ring to a conventional rectifier. Invention of 2 ). Furthermore, of the six rectifying walls, two rectifying walls except for four rectifying walls with inclined surfaces are provided with movable blades at the end on the impeller side, thereby improving measurement accuracy. The adjustment to be performed becomes possible (the invention of claim 3) .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
The impeller-type flow meter 10 of the present invention (hereinafter simply referred to as “flow meter 10”) is obtained by assembling the flow meter body 12 shown in FIG. 2 to an outer case 11 (see FIG. 1) attached in the middle of a water pipe. Become.
[0013]
In the outer case 11, an inflow port 11A opened on the left side in FIG. 1 and an outflow port 11B opened on the right side are formed, and a lower chamber 13 extending downward from the inflow port 11A, and a lower chamber 13 An upper room 14 located above is provided. Further, the upper room 14 and the lower room 13 communicate with each other in the vertical direction via the communication port 16. The flow meter body 12 is inserted and assembled into an upper surface opening 15 formed on the upper surface of the upper chamber 14, and the lower end portion of the flow meter body 12 is joined to the edge of the communication port 16.
[0014]
2 in the flow meter main body 12 is a cylindrical housing, and is formed by connecting a pair of cylindrical portions 50A and 50B arranged vertically with a plurality of ribs 52. The lower cylindrical portion 50B is opened up and down, and the blades 43 of the impeller 40 are accommodated in the lower cylindrical portion 50B, and the rectifier 20 is joined to the lower surface of the lower cylindrical portion 50B. ing. As indicated by the thick arrows in FIG. 1, the water flowing in the order from the lower chamber 13 of the outer case 11 to the rectifier 20 and the lower cylindrical portion 50B passes between the ribs 52 and 52 from the upper surface of the lower cylindrical portion 50B. Pass through to the upper room 14 of the outer case 11 and head toward the outlet 11B.
[0015]
As shown in FIG. 2, a shaft accommodating portion 53 hangs down on the lower surface of the upper cylindrical portion 50A so as to taper toward the center of the lower cylindrical portion 50B. A shaft 41 extending from the impeller 40 is accommodated.
[0016]
On the other hand, a meter unit 60 is attached to the upper surface of the upper cylindrical portion 50A, and the meter unit 60 counts and displays the integrated flow rate of water that has passed through the flow meter 10 in conjunction with the rotation of the impeller 40. In addition, when the upper cover 61 provided on the upper part of the meter unit 60 is opened, the flow rate display unit can be seen through the glass window 62.
[0017]
In FIG. 3, only the impeller 40 is shown. As shown in the figure, the impeller 40 includes, for example, twelve blades 43 projecting radially from the outer peripheral surface of the cylindrical body 42. Each blade 43 has a lower edge 43B (upstream edge) counterclockwise with respect to an upper edge 43A (downstream edge) of each blade 43 when viewed from the upper side in FIG. Prior to the turning direction, the entire blade 43 is twisted. Thereby, when water pressure is applied to the blades 43 from the upstream, the impeller 40 rotates so that the lower end edge 43B of the blades 43 precedes. That is, the impeller 40 rotates counterclockwise as viewed from above.
[0018]
The shaft 41 rises vertically upward from the center of the bottom surface of the cylindrical body 42, and the space between the shaft 41 and the inner surface of the cylindrical body 42 is reinforced by ribs 46.
[0019]
As shown in FIG. 4, a hollow having a lower end is formed in the core portion of the shaft 41, and a bearing 47 is assembled at a position near the lower end in the cavity. A support pin 21 provided in the rectifier 20 described later is inserted into the cavity from the lower end of the shaft 41, and the tip of the support pin 21 is abutted against the bearing 47.
[0020]
One end of the magnet coupling 44 is provided at the upper end portion of the shaft 41, and is disposed opposite to the other magnet coupling 44 fixed to the gear 64 constituting the meter unit 60 as shown in FIG. 2. Thereby, the rotation of the impeller 40 is transmitted as the rotation of the gear 64 of the meter unit 60.
[0021]
Further, a convex portion 48 is provided at the center of the upper end surface of the shaft 41, and a bearing member 49 is provided at a position facing the convex portion 48 in the meter unit 60 (FIG. 2). See).
[0022]
Now, as shown in FIG. 5, the rectifier 20 includes a central rectifier 22 according to the present invention at the inner center of a cylindrical cylindrical body 27, and, for example, six sheets from the central rectifier 22 toward the cylindrical body 27. The rectifying wall 70 has a structure extending radially.
[0023]
The cylindrical body 27 is opened up and down, and a slide ring 32 is assembled to an upper end edge thereof. Specifically, the slide ring 32 is formed with long holes 35 and 35 at two positions separated by 180 °, and a screw inserted into the long holes 35 and 35 is screwed into the upper end portion of the cylindrical body 27. . Then, the slide ring 32 can be rotated on the cylinder 27 by loosening the screw, and the slide ring 32 can be fixed to the cylinder 27 by tightening the screw at a desired position. In addition, lateral grooves 33, 33 that open toward the inside are formed at positions that are approximately 90 ° apart from the long holes 35, 35.
[0024]
The central rectifier 22 is disposed at a position closer to the upper end (downstream end) of the cylindrical body 27. The center rectifier 22 has a dome shape that is open at the top and is rounded downward and tapered. Further, the apex of the dome, that is, the lower end portion 22U of the central rectifying body 22 reaches a substantially intermediate position in the axial direction of the cylindrical body 27, and an axial core portion 22A is provided in the dome. A support pin 21 is erected upward from the upper end of the shaft core portion 22A, and the support pin 21 is inserted into the cavity of the shaft 41 as described above to rotatably support the impeller 40. For example, six ribs 26 extend radially from the shaft core portion 22 </ b> A, and a rectifying wall 70 is formed on an extension line of the ribs 26.
[0025]
Each of the plurality of rectifying walls 70 is parallel to the axial direction of the cylindrical body 27 in the vertical direction. The lower end edge of the rectifying wall 70 is inclined so as to gradually go downward as it goes from the central rectifying body 22 toward the cylindrical body 27, and the lower end edge 70 U of the rectifying wall 70 on the cylindrical body 27 side is the central rectifying body 22. Is located below the lower end 22U (see FIG. 4). As shown in FIG. 5, among the plurality (six) of rectifying walls 70, two rectifying walls 70B that are 180 degrees apart from each other are provided with movable blades 29, and the remaining (four) rectifying walls 70A. An inclined surface 28 is formed.
[0026]
The rectifying wall 70 </ b> B provided with the movable blade 29 has a recess 71 opened toward the impeller 40 in a portion near the cylindrical body 27. The movable blade 29 has a substantially rectangular flat plate shape corresponding to the recess 71 and is assembled in the recess 71. Specifically, the pin 34 inserted from the outer surface of the cylindrical body 27 is inserted into the lower end portion of the movable blade 29, and the movable blade 29 can tilt around the pin 34. An emboss 30 is projected and engaged with the upper end portion of the movable blade 29 toward the inside of the lateral grooves 33 and 33 of the slide ring 32. Thereby, with the rotation of the slide ring 32, both movable wings 29, 29 are tilted symmetrically.
[0027]
The inclined surface 28 is formed on a surface of the rectifying wall 70 </ b> A facing the direction opposite to the rotation direction of the impeller 40 (counterclockwise direction when viewed from above in FIG. 5). In the present embodiment, the inclined surface 28 is formed only on the impeller 40 side of the rectifying wall 70A, and the portion other than the inclined surface 28 in the rectifying wall 70A is flat. The portion of the rectifying wall 70 </ b> A on the impeller 40 side is configured such that the thickness of the rectifying wall 70 </ b> A gradually decreases as the thickness of the rectifying wall 70 </ b> A approaches the end near the impeller 40.
[0028]
Now, as shown in FIG. 4, the rectifier 20 is provided with a dam portion 80 that protrudes inward from a position below the center rectifier 22 in the inner surface of the cylindrical body 27. Specifically, the dam portion 80 is formed by fitting a flat ring to the cylindrical body 27 and fixing the ring against the lower end edge 70 </ b> U of the rectifying wall 70. Thereby, the dam part 80 is arrange | positioned in the position of the upstream rather than the lower end part 22U of the center rectification body 22. FIG. The opening area of the cylindrical body 27 is narrowed by the dam portion 80.
[0029]
Next, the operation of this embodiment configured as described above will be described.
As shown by the thick line arrows in FIG. 1, the water that flows into the lower chamber 13 from the inlet 11 </ b> A of the outer case 11 flows along the rectifying walls 70 (70 </ b> A, 70 </ b> B) of the rectifier 20, and to the impeller 40. Head. The impeller 40 rotates by receiving the water guided by the rectifying walls 70 (70A, 70B) by the blades 43. The water that has passed through the impeller 40 flows out between the ribs 52, 52 of the cylindrical housing 50 to the side of the flow meter main body 12, and travels to the outlet 11B through the upper chamber 14 of the outer case 11. The rotation of the impeller 40 is transmitted to the meter unit 60 through the magnet couplings 44 and 44, and the flow rate of water is measured and displayed.
[0030]
<Experiment 1>
The following experiment was conducted to examine the effect of the “weir portion 80” according to the present invention. The experimental procedure is as follows.
(1) The flowmeter 10 of the present invention having the rectifier 20 having the dam portion 80 and the conventional flowmeter having the rectifier not having the dam portion 80 are passed through at a predetermined flow rate, The thrust load applied to the impeller of each flow meter at the set flow rate value was obtained.
(2) The experimental results were graphed as shown in FIG.
[0031]
Each flow meter is provided with a movable blade 29. In this experiment, each movable blade 29 is set substantially vertically.
[0032]
Comparing the flow meter 10 of the present invention with the conventional flow meter based on the graph of FIG. 6, the thrust load of the flow meter 10 of the present invention is the thrust load of the conventional flow meter at any set flow value. It is a smaller value. From this, it was found that the thrust load applied to the impeller 40 is reduced by forming the weir 80 in the rectifier 20.
[0033]
<Experiment 2>
Next, the thrust by the ratio A / B of the flow area A (see FIG. 10 ) in the portion surrounded by the weir 80 with respect to the fluid passage area (flow area) B in the opening on the impeller 40 side of the cylindrical body 27 The following experiment was conducted to investigate the difference in load reduction effect. The procedure of the experiment is the same as that of the experiment 1 except that the ratio A / B is set to 115%, 125%, and 140%. Therefore, the description is omitted.
[0034]
As shown in the graph of FIG. 7, the thrust load value decreases as the ratio A / B decreases at any set flow rate value. From this, it can be seen that the thrust load reduction effect increases as the amount of protrusion of the dam 80 to the inside of the cylinder 27 increases and the flow area A of the portion surrounded by the dam 80 decreases.
[0035]
<Experiment 3>
Next, an experiment was conducted to examine the adaptability of the flowmeter of the present invention to the OIML standard. The experimental procedure is as follows.
(1) The flowmeter 10 of the present invention provided with the rectifier 20 having the dam portion 80 and the flowmeter provided with the conventional rectifier not having the dam portion 80 are passed through at a preset flow rate, The measured value of each flow meter at the set flow rate value was obtained.
(2) The instrumental difference of each flowmeter was calculated for each set flow rate and graphed (instrumental difference curve).
[0036]
Here, the “instrument difference” is obtained by the following equation, where X is the measured value and Y is the true value.
Instrumental difference (%) = ((X−Y) / Y) · 100
[0037]
The experimental results are shown in FIG. 8, in which the instrumental difference curve of the flowmeter 10 of the present invention is represented by a broken line, and the instrumental difference curve of the conventional flowmeter is represented by a solid line.
[0038]
As shown in FIG. 8, the instrumental difference peak of the flowmeter 10 of the present invention is smaller than the instrumental peak of the conventional flowmeter over almost the entire set flow value (Q1 to Q4 in FIG. 8). . From this, it was found that the flowmeter of the present invention is more accurate than the conventional flowmeter.
[0039]
Further, an instrumental difference allowable range based on the OIML standard surrounded by a thick line in FIG. 8 (the instrumental difference between the set flow rate values Q2 to Q3 is within ± 5%, and the instrumental difference between Q3 and Q4 is ± 2 When the flowmeter 10 of the present invention is out of this allowable range in the small flow rate range, the flow meter 10 of the present invention has this allowable range in the entire range from the small flow rate range to the large flow rate range. It is in the range. From this, it has been found that the flowmeter 10 of the present invention is adapted to the OIML standard and can be measured with high accuracy from a small flow rate range to a large flow rate range.
[0040]
<Other embodiments>
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.
[0042]
(1) In the above embodiment, in accordance with but an inner circumferential surface of the dam portion 80 was parallel to the axial direction of the cylindrical body 27, as weir portion 120 shown in FIG. 9, directed from the upstream side to the downstream side, The taper may be formed so that the inner diameter becomes small.
[Brief description of the drawings]
1 is a cross-sectional view of a flow meter according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a flow meter body. FIG. 3 is a perspective view of an impeller. FIG. 4 is a cross-sectional view of a rectifier and an impeller. ] Perspective view of rectifier [Fig. 6] Graph showing the result of Experiment 1 [Fig. 7] Graph showing the result of Experiment 2 [Fig. 8] Graph showing the result of Experiment 3 [Fig. 9] Other Embodiments ( FIG . 10 is a conceptual diagram showing a flow area of a portion surrounded by a weir and a flow area at an opening on the impeller side of a cylindrical body. FIG. 11 is a cross section of a conventional flow meter. Figure 12 is a cross-sectional view of a conventional rectifier eXPLANATION oF REFERENCE nUMERALS
DESCRIPTION OF SYMBOLS 10 ... Impeller-type flow meter 20 ... Rectifier 22 ... Central rectifier 27 ... Cylindrical body 40 ... Impeller 8 0, 1 20 ... Weir part

Claims (4)

A rectifier arranged adjacent to the lower surface of the impeller among the impeller flowmeters that measure the flow rate based on the rotation of the impeller provided with 12 twisted blades radially projecting from the outer peripheral surface of the cylindrical rotating body. There,
A cylindrical body that guides fluid to the impeller, and a tapered dome that is disposed near the impeller and is rounded downward in a central portion of the cylindrical body, and the blade on the upper surface A central rectifier having a support pin for pivotally supporting a vehicle, and a radial bulge extending laterally from the central rectifier and passing between the cylindrical bodies, and a lower edge portion from the central rectifier 6 rectifying walls inclined diagonally downward ,
Of the six rectifying walls, formed on the four rectifying walls excluding the two rectifying walls located 180 degrees apart from each other, the surface facing the direction opposite to the rotation direction of the impeller An inclined surface formed by inclining the rectifying wall so as to be thinned toward the end on the impeller side;
A weir portion that protrudes inward from a position below the central rectifier and the rectifying wall of the inner surface of the cylindrical body and reduces the inner diameter of the cylindrical body ,
When the area of the part through which the fluid passes inside the weir part is A, and the area of the part through which the fluid passes through the opening on the impeller side of the cylindrical body is B,
R = A / B
The ratio R calculated | required by (1) was 115-140%, The rectifier characterized by the above-mentioned. 2. The rectifier according to claim 1, wherein the dam portion is a flat ring that is fitted inside the cylindrical body . Of the six rectifying walls, the two rectifying walls except for the four rectifying walls formed with the inclined surface are provided with movable vanes at the end on the impeller side, The rectifier according to claim 1, wherein the rectifier is configured to be tiltable forward and backward in a rotation direction of the impeller . An impeller-type flow meter comprising the rectifier according to any one of claims 1 to 3.

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