JP3518276B2 - Float position detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a float position detecting device using a one-dimensional image sensor, and more particularly to a one-dimensional float position detecting device whose shape is miniaturized.

[0002]

2. Description of the Related Art Conventionally, a float which can be moved up and down is arranged in a flow path to measure a flow velocity, and the position of the float is determined by a CCD.
A float position detecting device is used, which is designed to be read by a one-dimensional image sensor such as. In this float position detecting device, as shown in FIG. 7, a transparent tube 101 is vertically arranged. The transparent tube 101 is a taper tube configured such that the diameter of the upper portion is large and the diameter thereof is gradually reduced as it goes downward, and is arranged so that the liquid flows upward from below. The transparent tube 101 has a conical float 10
2 is inserted vertically with its apex facing downward. If the flow rate is high, the float 102 is pushed up and moves above the transparent tube 101, and if the flow rate is low, it moves downward. Then, the light from the light source 103 is guided to the transparent tube 101 as parallel light through the lens 104. In this way, the position of the float 102 is detected by the CCD image sensor 105. FIG. 7B is a diagram showing the relationship between the output from the CCD image sensor 105 and the float 102. Then, by comparing the CCD output with a predetermined threshold value, the end of the float 102 can be detected, and the flow rate can be measured from the level of the float.

Further, as shown in FIG. 8A, light is emitted from a light source 110 toward a transparent tube 101, and the diffuse reflection light is C
A float position detecting device that receives light by the CD image sensor 105, or a configuration in which diffused reflected light is once condensed by the lens 111 to form an image on the CCD image sensor 105 as shown in FIG. 8B. It is considered.

[0004]

In the float position detecting device according to the first conventional example as described above, parallel light is emitted from a light source using a lens as shown in FIG. Since it becomes large, there is a drawback that it is difficult to reduce the size. Further, since the float position detecting device according to the second conventional example shown in FIG. 8 (a) does not form an image, there is a drawback that it is difficult to accurately detect the float position. Furthermore, FIG.
When the reflected light from the float is focused using a lens as in the third conventional example shown in (b), the shape of the light receiving system becomes large, and a small and highly accurate detection device can be configured. It had the drawback of being difficult.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a small and highly accurate float position detecting device.

[0006]

The invention according to claim 1 of the present application moves up and down in a transparent tube according to the flow rate of the liquid.
And a one-dimensional image sensor for detecting the light from the float , and the flow.
And a holder for holding the light projecting means, the one-dimensional image sensor and the rod lens array, the light projecting means comprising: Multiples arranged in a row
It is configured to include a light projecting element, and the space between the light projecting elements is
Widen the central part and gradually narrow it from the central part to the end part
It was done like this.

[0007] The present invention of claim 2 is in a transparent tube odor
Light to the float that moves up and down according to the flow rate of the liquid.
A projecting unit that emits light and detects light from the float 1
The three-dimensional image sensor and the light from the float
Rod lens array for imaging on a three-dimensional image sensor
And the light projecting means, the one-dimensional image sensor, and the
A holder for holding the rod lens array,
The holder is an opening to which the one-dimensional image sensor is attached.
A port that clearly defines the mouth and the line that runs vertically through the center of the opening.
The one-dimensional image sensor has a target mark,
The center line of the received light matches the target mark
Is attached to the holder in this manner.
It

[0008]

According to the invention of claim 1 of the present application having such a feature, light is projected onto the object detection area by the light projecting means, and reflected light from the object detection area is one-dimensionally imaged through the rod lens array. Guide to the sensor. Since the rod lens array forms the reflected light into an erecting equal-magnification image and forms the image on the image sensor, the level of the reflected light can be accurately detected. Further, the light projecting means is composed of a plurality of light projecting elements, and the interval between the light projecting elements is widened in the central portion so that the light intensity along the array direction is substantially constant. Further, according to the invention of claim 2 , even when the light receiving line of the one-dimensional image sensor is deviated from the center thereof, the target mark can be used to mount the holder at the center position of the holder, and variations in the one-dimensional image sensor can be absorbed. it can.

[0010]

1 is an assembly configuration diagram showing a configuration of a detector according to an embodiment of the present invention, FIG. 2 is a perspective view showing an attachment state to a float case, and FIG. 3 is a base thereof. A side view and a front view of the holder, and FIG. 4 are vertical sectional views of the detector. As shown in these figures, the detector 1 according to the present embodiment is attached to a float case 2 for detecting a float position. As shown in FIG. 2, the float case 2 is a substantially rectangular parallelepiped case having a visible light filter 3 attached to the front surface thereof, and an opening portion is provided on the front surface. The visible light filter 3 is a filter that transmits visible light and blocks infrared light. As mentioned above, float case 2
A transparent transparent tube 4 is vertically arranged in the interior of the transparent tube 4, and the transparent tube 4 is provided with a scale for reading the flow rate. A conical float 5 similar to the conventional example is vertically movably arranged inside the transparent tube. On the back surface of the float case 2, flow path pipes (not shown) are provided above and below, and a rectangular opening similar to the front surface is provided between them.
The detector 1 according to this embodiment is configured to be removable.

As shown in FIG. 1, the detector 1 according to this embodiment comprises a front case 10 and a rear case 11, which form a casing. The front case 10 has a substantially rectangular opening 1 at the center.
0a, and the frame-shaped portion 10b is attached except the attachment portions at the four corners. The transparent cover 12 is attached to the opening 10a, and the base holder 13 is attached to the inside of the frame-shaped portion 10b. As shown in FIGS. 3A and 3B, the base holder 13 is a member in which a recess 14 is formed on the left side and a rectangular opening 15 is formed in the central portion on the back side, and a printed circuit board is formed on the right side. 16, a printed circuit board 17 is attached to the back surface. The printed board 17 is a board on which a CCD element 18 which is a one-dimensional image sensor is mounted, and mounting holes at both ends are long holes so that the mounting position can be finely adjusted. The printed circuit board 16 drives the CCD element 18, discriminates the detection signal from the CCD element 18 with a predetermined threshold value, and converts it into a flow rate signal.
19 is implemented. Further, the rod lens array 20 is inserted into the recess 14 on the left side of the base holder 13, and after the rod lens array 20 is further inserted, the base cover 21 that covers the opening of the base 13 is attached. The base cover 21 has a plurality of light projecting elements 22 for emitting infrared light, for example.
The element holder 23 holding the element holder 23 and the printed circuit board 24 on which the element holder 23 is mounted can be fixed. Here, the light projecting element 22 and the element holder 23 open the light 1
It constitutes a light projecting means for irradiating the object detection area via 0a. Further, the base holder 13 has a thin slit formed on the left side surface thereof, and the infrared filter 2 which allows infrared rays to pass therethrough.
5 is inserted. Here, the rod lens array 20 is shown in FIG.
As shown in Fig. 4, a large number of rod lenses in the X-axis direction are arranged in one row in the X-axis direction, and the erecting equal-magnification image is coupled behind it to set the optical distance to an arbitrary length. To do. That is, the spread of the incident light and the spread of the emitted light can be the same, and the light can be guided to the light receiving element, in this case the CCD.

The CCD element 18 often has a one-dimensional light receiving line which is displaced from the center line of the package of the CCD element 18. Therefore, when the CCD element 18 is simply mounted so that the center thereof coincides with the center of the rod lens array 20, there is a drawback that the light receiving level of the incident light from the rod lens array 20 varies depending on the position. . Therefore, as shown in FIGS. 1, 4 and 3B, the target mark 26 for clearly indicating the center of the opening 15 to which the CCD is attached is provided on the base holder 13.
a and 26b are provided. Target marks 26a, 26b
Defines a line that vertically penetrates the center of the rectangular opening 15, and can be configured as, for example, a mountain-shaped projection protruding from the upper surface and the lower surface of the inner wall of the case as illustrated.

As a light source used in this embodiment, a plurality of light emitting elements 22, for example, light emitting diodes are arranged in a line. Here, when a large number of light emitting diodes are arranged at regular intervals as shown in FIG. 5A, the amount of light only in the central portion is larger than that in the peripheral portion, so that it is difficult to detect the float correctly. Therefore, in the present embodiment, as shown in FIG. 5B, the interval in the central portion is increased, and the interval is decreased toward the periphery. Then, this interval is appropriately set so that a substantially uniform light intensity can be obtained regardless of the position of the light emitting diode.

Next, the assembly of this detector will be described. The CCD element 18 is mounted on the printed board 17 in advance and attached to the back surface of the base holder 13. At this time, as viewed from the front case side of the base holder 13, the center line of the light reception should pass through the center of the opening on the back surface of the base holder 13, that is, the target mark 2 instead of the package of the CCD element 18.
The position of the printed circuit board 17 is adjusted and attached so that the printed circuit board 17 and 6a and 26b coincide with each other. Then, the infrared filter 25 is inserted. When the rod lens array 20 is attached to the recess 14 of the base holder 13, the vertical center line of the rod lens array 20 and the center lines of the target marks 26a and 26b and the light reception of the CCD element 18 can be accurately matched. After the rod lens array 20 is attached, the base cover 21 covers the opening of the base holder 13, and the printed circuit board 24 on which the detection circuit portion is mounted is attached from the left side surface. Board 2
The light emitting element holder 23 is mounted in advance on 4.
Then, the rear case 11 is fixed to the front case 10. After constructing the detector in this way, the float position detecting device can be constructed by fixing the detector 1 to the back surface of the float case 2 as shown in FIG.

When the detector 1 is attached to the float case 2 in this manner, substantially uniform light is emitted from the light projecting element 22 to the transparent tube 4. Therefore, the position on the float that differs depending on the flow rate can be detected by the CCD element 18 via the rod lens array 20 as shown in FIG. FIG. 6 is a diagram showing the output signal of this CCD. By discriminating the output signal with a predetermined threshold value, the signal indicating the position of the upper end of the float 5 can be detected as a signal corresponding to the flow rate.

[0016]

Further, although the target line is formed as a mountain-shaped projection in this embodiment, it goes without saying that a mark may be simply provided on the inner surface of the opening.

[0018]

As described in detail above, according to the present invention, since the reflected light from the float is guided to the one-dimensional image sensor by using the rod lens array, the size of the entire detector is reduced. The effect that can be obtained is obtained. Further, since the light is focused on the one-dimensional image sensor, it is possible to accurately detect the position. The invention of claim 1
Then, the light projecting section is configured using a plurality of light projecting elements,
Since the intervals of the light projecting elements are wide in the central part and dense in the peripheral parts, the light intensity can be made substantially constant. Further, in the invention of claim 2 , a target mark is provided on the base holder so that the light receiving line of the one-dimensional image sensor matches the rod lens array, and the light receiving line of the one-dimensional image sensor is fixed accordingly. Therefore, there is an effect that the position can be accurately detected by accurately aligning with the center of the rod lens array regardless of variations in the detection line of the one-dimensional image sensor.

[Brief description of drawings]

FIG. 1 is a float position detecting device according to an embodiment of the present invention.
It is an assembly lineblock diagram of a table .

FIG. 2 is a diagram showing a float position detecting device and a float according to the present embodiment.
It is a perspective view showing a float case to which a funnel position detecting device is attached.

FIG. 3 is a front view and a side view of a base holder according to the present embodiment.

FIG. 4 is a vertical cross-sectional view of the float position detecting device according to the present embodiment.

FIG. 5 is a graph showing changes in the arrangement of the light projecting elements and changes in light intensity.

FIG. 6 is a diagram showing a relationship between an output from a CCD image sensor and a float.

FIG. 7 is a schematic diagram showing a configuration of a float position detecting device according to a conventional example.

FIG. 8 is a schematic diagram showing a configuration of a float position detecting device according to a conventional example.

[Explanation of symbols]

1 detector 2 float cases 3 Visible light filter 4 transparent tube 5 floats 10 front case 11 rear case 12 Transparent substrate 13 Base holder 14 hollow 15 openings 16, 17, 24 substrates 18 CCD element 19 IC 20 Rod lens array 21 base cover 22 Projector 25 infrared filter 26a, 26b Target mark

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-36029 (JP, A) JP-A-1-44818 (JP, A) JP-A-9-203631 (JP, A) Actual flat 5- 57628 (JP, U) Actual public Hei 7-19168 (JP, Y2) Actual public Sho 63-10484 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 1/22 G01F 23 / 30 G01F 23/56 G01F 23/64 G01D 5/26 G01B 11/00

Claims (2)

(57) [Claims] 1. A transparent tube having a liquid flow rate depending on the flow rate of the liquid.
A light projecting means for projecting light onto a float moving downward, a one-dimensional image sensor for detecting light from the float , a rod lens array for forming an image of the light from the float on the one-dimensional image sensor, And a holder that holds the one-dimensional image sensor and the rod lens array , wherein the light projecting unit includes a plurality of light projecting elements arranged in a line.
It is configured with a wide space in the center part between the light projecting elements.
And gradually narrowed from the center to the edges.
Float position detection device. 2. The transparent tube is provided with an upper portion depending on the flow rate of the liquid.
Projecting means for projecting light to a float moving downward, and one-dimensional image sensor for detecting light from the float
And the light from the float is coupled to the one-dimensional image sensor.
An image forming rod lens array, the light projecting means, the one-dimensional image sensor, and the lock.
A holder for holding the lens array, and the holder to which the one-dimensional image sensor is attached.
And the line that runs vertically through the center of the opening.
The one-dimensional image sensor has a target mark
The holder so as to match the target mark
Float position detector attached to.