JP6569112B1 - Flow rate detection device and flow rate detection method - Google Patents

Abstract

Provided are a flow rate detection device and a flow rate detection method that have robustness for alignment of light projecting means even when detecting the number of rotations of a rotating body that rotates on a plane according to the flow of fluid. In order to solve the above problems, a flow rate detection device 1 for detecting the number of rotations of a rotating body 11 rotating on a plane according to the flow of a fluid, emits parallel light toward the rotating body 11. The light projecting unit 3, the light receiving unit 4 that detects a change in the optical path of the parallel light reflected by the rotating body 11, and the light projecting unit 3 and the rotating body 11 are disposed between the light projecting unit 3 and the rotating body 11. Provided is a flow rate detection device 1 including an optical path changing unit 5 that refracts the parallel light so as to have a smaller positive angle and receives the reflected parallel light to a light receiving unit 4. [Selection] Figure 1

Description

  The present invention relates to a technique for detecting the flow rate of a fluid such as water flowing through a water pipe or the like.

  When a water meter is shipped, an inspection is performed in which the measured value of the water meter is measured by irradiating a pilot provided in the water meter to detect reflected light and detecting the number of revolutions of the pilot. Has been done. The apparatus and method used in this inspection are disclosed in, for example, Patent Document 1 below.

JP, 2015-010976, A

  In the flow rate detection device 1 disclosed in Patent Document 1, as described in paragraph [0024] of the same document, a light beam having a diameter larger than the diameter is irradiated from directly above the water-passing pilot 92 composed of an octahedron. Therefore, even if the position of the light projecting unit 2 is slightly deviated from directly above the water passing pilot 92 at the time of inspection, the robustness (robustness) that does not affect the detection of the reflected light is realized.

  However, the pilot is not composed of the polyhedron as disclosed above in Patent Document 1 (hereinafter referred to as “polyhedron pilot”), but planar reflection as shown in FIGS. 6 (a) and 6 (b). If the plate 11b is composed of a planar impeller 11a rotating around the central axis 11c (hereinafter referred to as “planar reflection pilot”), the above-described robustness is not easy to realize. is there. In FIG. 6, the impeller 11a is displayed in black (the same applies to FIG. 1).

  That is, in the same way as described above, when a light beam having a diameter larger than the diameter is irradiated from directly above the flat reflection pilot 11, it is reflected by the flat reflection plate 11b unlike the polyhedron pilot. It does not change with the rotation of the car 11a.

  On the other hand, if the diameter of the light beam applied to the plane reflection pilot 11 is reduced, the positioning of the light projecting means with respect to the plane reflection pilot 11 requires accuracy.

The present invention has been made in order to solve the above-described problems. Even when detecting the number of rotations of a rotating body that rotates on a plane according to the flow of fluid, the present invention is robust with respect to alignment of the light projecting means. An object of the present invention is to provide a flow rate detection device and a flow rate detection method having

  In order to solve the above-mentioned problem, the present invention is a flow rate detection device that detects the number of rotations of a rotating body that rotates on a plane according to the flow of fluid, and a light projecting unit that emits parallel light toward the rotating body; A light receiving means for detecting a change in the optical path of the parallel light reflected by the rotating body, and a light receiving means disposed between the light projecting means and the rotating body, and the incident angle with respect to the plane is a positive angle smaller than 90 degrees. A flow rate detecting device is provided that includes an optical path changing unit that refracts the parallel light and receives the reflected parallel light to a light receiving unit.

  In order to solve the above-mentioned problem, the present invention is a flow rate detection method for detecting the number of rotations of a rotating body that rotates on a plane in accordance with the flow of a fluid. A second step of causing the optical path changing means to refract the parallel light so that the incident angle with respect to the plane is a positive angle smaller than 90 degrees and irradiate the rotating body; There is provided a flow rate detection method comprising a third step of causing a means to detect a change in the optical path of parallel light reflected by the rotating body.

  According to the present invention, it is possible to provide a flow rate detection device and a flow rate detection method that have robustness with respect to alignment of the light projecting means even when the number of rotations of a rotating body that rotates on a plane according to the flow of fluid is detected. Can do.

It is a figure which shows the structure of the flow volume detection apparatus 1 which concerns on embodiment of this invention. It is a perspective view which shows the structural example of the optical path change part 5 shown by FIG. It is a figure which shows the image formed in the light-receiving part 4 with the light reflected in the plane reflection pilot 11 shown by FIG. It is a figure for demonstrating operation | movement of the light-receiving part 4 shown by FIG. It is a figure for demonstrating the case where the rotation speed of the polyhedron pilot 12 is detected using the flow volume detection apparatus 1 shown by FIG. FIGS. 6A and 6B are diagrams showing a configuration of the plane reflection pilot 11 shown in FIG. 1, FIG. 6A is a side view showing the configuration when the plane reflection pilot 11 is viewed from the side, and FIG. It is a top view which shows a structure when 11 is seen from upper direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 1 is a diagram showing a configuration of a flow rate detection device 1 according to an embodiment of the present invention. As shown in FIG. 1, the flow rate detection device 1 according to the embodiment of the present invention is provided in a water meter 10 that measures the flow rate of a fluid such as water, and the flat reflector 11b is in accordance with the flow of the fluid. A flow rate detection device 1 for detecting the number of rotations of a plane reflection pilot 11 comprising a planar impeller 11a rotating above, a light projecting unit 3 that emits parallel light toward the plane reflection pilot 11, and a plane reflection plate The light receiving unit 4 that detects a change in the optical path of the parallel light reflected by the light beam 11b, the light projecting unit 3, and the plane reflection pilot 11, and is a positive light whose incident angle with respect to the plane reflection plate 11b is smaller than 90 degrees. An optical path changing unit 5 that refracts the parallel light to have an angle and causes the light receiving unit 4 to receive the parallel light reflected by the planar reflecting plate 11b. The light receiving unit 4 includes light receiving sensors 4a and 4b described later.

  Here, for example, the light projecting unit 3 and the light receiving unit 4 are housed in a common housing to form the flow rate measuring unit 2, and the optical path changing unit 5 is configured separately from the housing, thereby enabling inspection. The optical path changing unit 5 may be detachable from the target water meter 10. The advantages of such a configuration will be described later.

  The optical path changing unit 5 is arranged such that one of the circular convex lenses cut along an arbitrary diameter coincides with the traveling direction of the parallel light emitted toward the plane reflection pilot 11 with the optical axis of the convex lens. A semicircular lens 7 and a gap 6 that directly reflects the parallel light reflected by the planar reflecting plate 11 b onto the light receiving unit 4. In FIG. 1, the semicircular lens 7 is displayed in a horizontal stripe pattern (the same applies to FIG. 2), and the gap 6 is displayed in a mesh pattern.

  Here, as shown in FIG. 2, the gap portion 6 is formed of a hole such as a circle provided on the bottom surface of the lens holder LH, and the semicircular lens 7 is covered with the lens holder LH so as to cover an approximately half region of the hole. Placed on. In FIG. 2, the cross section of the semicircular lens 7 obtained by cutting the convex lens along an arbitrary diameter as described above is displayed in a vertical stripe pattern.

  By having such a configuration, the optical path changing unit 5 collects the parallel light received by the semicircular lens 7 and irradiates the parallel reflection pilot 11 with the parallel light reflected by the flat reflection plate 11b. There is an effect that the light-receiving part 4 is directly detected by passing through the gap part 6 without being condensed again by the lens.

  Here, according to the semicircular lens 7, by condensing the received parallel light, the brightness of the light irradiated to the planar reflection pilot 11 can be increased, and as a result, the brightness of the reflected light can also be increased. It is possible to improve the detection reliability by improving the signal-to-noise ratio (S / N ratio) in detection in the light receiving unit 4.

  Further, according to the gap 6, the parallel light reflected by the plane reflecting plate 11b to be passed becomes divergent light, and the formed image is enlarged in proportion to the distance from the plane reflecting plate 11b. By increasing the distance up to 4, it is possible to obtain an effect that the structural design of the light receiving sensors 4a and 4b can be facilitated.

  Then, as shown in FIG. 3, the parallel light that has passed through the gap 6 is shielded by each blade of the impeller 11a, and the shadow DI is formed between the adjacent blades. An image is formed in which bright portions BI formed by light passing through are alternately arranged on an arc.

  Here, it is preferable that the semicircular lens 7 has a function of condensing the received parallel light so as to cover half of the rotation region on the planar reflection plate 11b of the impeller 11a. If the semicircular lens 7 has such a function, the parallel light reflected by the planar reflecting plate 11b forms the image shown in FIG. The

  Next, the flow rate detection method according to the embodiment of the present invention will be described taking as an example a case where the flow rate detection method is realized by the operation of the flow rate detection device 1 having the above-described configuration. Needless to say, this flow rate detection method is not limited to the case where the flow rate detection device 1 is used.

  In the first step, the light projecting unit 3 projects parallel light toward the plane reflection pilot 11. In the second step, the optical path changing unit 5 refracts the parallel light so that the incident angle with respect to the planar reflecting plate 11b becomes a positive angle smaller than 90 degrees, and irradiates the planar reflecting pilot 11 with it. In the third step, the light receiving unit 4 is caused to detect a change in the optical path in the parallel light reflected by the plane reflection pilot 11.

  Here, as shown in FIG. 4, the bright part BI imaged on the light receiving part 4 rotates, for example, in the direction of the arrow in accordance with the rotation of the impeller 11a. For this reason, detection by the light receiving unit 4 in the third step is performed by simultaneously sensing a change in luminance that occurs when the bright part BI crosses two light receiving sensors 4a and 4b that are separated from each other by the light receiving sensors 4a and 4b. This is realized by obtaining the differential.

  Note that a technique for measuring the number of rotations of the rotating body by obtaining such a differential has already been disclosed in FIG.

  According to such a flow rate detection method, the parallel light is refracted so that the incident angle with respect to the flat reflecting plate 11b becomes a positive angle smaller than 90 degrees and is irradiated to the flat reflecting pilot 11, so that the parallel light is flat. Even when the light is reflected by the reflecting plate 11b, as can be easily seen from FIG. 5 in which the polyhedron pilot 12 is the inspection object, the light received by the reflecting surface having the inclination angle is reflected from the top to the polyhedron pilot 12. An action that is physically equivalent to that when parallel light is applied can be produced.

  For this reason, when irradiating parallel light from the light projecting unit 3 to the polyhedron pilot 12, even if the light projecting unit 3 is slightly deviated from immediately above the polyhedron pilot 12, the influence on the detection result by the light receiving unit 4 can be reduced. Robustness in matching can be realized even when the inspection target is the plane reflection pilot 11.

  At this time, it is preferable that the optical path changing unit 5 collects the received parallel light so as to cover half of the rotation region on the planar reflection plate 11b of the impeller 11a.

  This is because even if the position of the plane reflection pilot 11 is deviated within the condensed range, the detection of the reflected light by the light receiving unit 4 can be prevented from being affected at all.

  In the third step, it is preferable that the light receiving unit 4 directly detect the parallel light reflected by the plane reflection pilot 11. This is because the structure design of the light receiving unit 4 can be facilitated as described above.

  In the above, the plane reflection pilot 11 shown in FIG. 6 may have a structure that reflects light on the surface of the impeller 11a instead of the plane reflection plate 11b. In this case, the shadow part DI and the bright part BI in FIG. 3 are merely interchanged, and the flow rate detection device 1 can operate in the same manner as described above.

  As described above, according to the flow rate detection device 1 and the flow rate detection method according to the embodiment of the present invention, the planar reflection including the impeller 11a that rotates on the planar reflection plate 11b according to the flow of fluid such as water. When detecting the number of revolutions of the pilot 11, even when the light projecting unit 3 is displaced from immediately above the plane reflection pilot 11, the influence on the detection result of the reflected light by the light receiving unit 4 can be reduced. A flow rate detection device 1 and a flow rate detection method having the characteristics can be provided.

  Further, as shown in FIG. 5, when the water meter 10 having the polyhedron pilot 12 is to be inspected, the optical path changing unit 5 is removed from the flow rate detecting device 1 shown in FIG. By using this to detect the number of rotations of the polyhedron pilot 12, even when the light projecting unit 3 is shifted from directly above the polyhedron pilot 12, the influence on the detection result of the reflected light by the light receiving unit 4 can be reduced. Can also be realized.

DESCRIPTION OF SYMBOLS 1 Flow detection apparatus, 2 Flow measurement part, 3 Light projection part, 4 Light reception part, 5 Optical path change part, 6 Gap part, 7 Semicircular lens, 11 Planar reflection pilot, 11a Impeller, 11b Plane reflection board.

Claims (5)

A flow rate detection device that detects the number of rotations of a rotating body that rotates on a plane according to the flow of fluid,
A light projecting means for emitting parallel light toward the rotating body;
A light receiving means for detecting a change in an optical path in the parallel light reflected by the rotating body;
The parallel light is disposed between the light projecting means and the rotating body, refracts the parallel light so that the incident angle with respect to the plane is a positive angle smaller than 90 degrees, and the reflected parallel light is received by the light receiving means. To receive light ,
A semicircular lens arranged such that one of the circular convex lenses is cut along an arbitrary diameter, and the optical axis of the convex lens coincides with the traveling direction of the parallel light emitted toward the rotating body;
A flow rate detection device comprising: an optical path changing unit including a gap portion that directly reflects the reflected parallel light onto the light receiving unit . The flow rate detection device according to claim 1 , wherein the semicircular lens collects the received parallel light so as to cover a half of a rotation region on the plane of the rotating body.   The flow rate detection device according to claim 1, wherein the light projecting unit and the light receiving unit are housed in a common housing, and the optical path changing unit is separate from the housing. A flow rate detection method for detecting the number of rotations of a rotating body that rotates on a plane according to the flow of fluid,
A first step of causing the light projecting means to project parallel light toward the rotating body;
The optical path changing unit refracts the parallel light so that the incident angle with respect to the plane is a positive angle smaller than 90 degrees and irradiates the rotating body, and receives the received parallel light on the plane of the rotating body. A second step of collecting light to cover half of the rotation area ;
A flow rate detection method comprising a third step of causing a light receiving means to detect a change in an optical path in the parallel light reflected by the rotating body. The flow rate detection method according to claim 4 , wherein in the third step, the light receiving unit directly detects the parallel light reflected by the rotating body.

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