Turbidity measuring device

Abstract

The present invention shortens an optical path length more than in conventional devices, even while providing a cleaning mechanism that includes a cleaning body that cleans an entrance window and an exit window. This turbidity measuring device is characterized by including: a cell including a measuring space that is formed between a light source and a light detection unit and that accommodates a liquid to be measured, and an entrance window that guides light from the light source to the measuring space, and an exit window that guides the light from the measuring space to the light detection unit; and a cleaning mechanism that cleans the entrance window and the exit window. This turbidity measuring device is also characterized by the cleaning mechanism including: a cleaning body that cleans the entrance window and the exit window; and a drive unit that is provided outside the measuring space, retracts the cleaning body to outside the measuring space at a time of measuring, and moves the cleaning body into the measuring space at a time of cleaning.

Description

Technical Field

[0001] The present invention relates to a turbidity measuring device.

Background Art

[0002] When measuring a measurement target liquid containing various components, dirt may adhere to the inner surface of a cell that forms a measurement space for containing the measurement target liquid and measuring turbidity. In such a case, if dirt adheres to the incident window where light from the light source is incident or the exit window where the light transmitted through the measurement target liquid or scattered by the measurement target liquid exits toward the detector among the inner surfaces of the cell, it may affect the turbidity measurement.

[0003] Therefore, as shown in Prior Arts 1 to 3, it is conceivable to arrange a cleaning body for cleaning dirt adhering to the incident window and the exit window inside the cell, and drive this cleaning body to clean the incident window and the exit window.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when measuring a measurement target liquid containing a large amount of contaminants such as drainage, it becomes difficult for light to pass through the measurement target liquid. Therefore, in order to further improve the measurement accuracy of turbidity measurement by transmitted light, it is required to shorten the optical path length from the light source to the photodetector.

[0006] However, when the cleaning body is placed inside the measurement space, as in the conventional method, there is a problem in that it is difficult to shorten the optical path length in order to place the cleaning body inside the measurement space.

[0007] This invention has been made in view of the aforementioned problems, and its main objective is to shorten the optical path length compared to conventional designs while still providing a cleaning mechanism that includes a cleaning body for cleaning the entrance window and the exit window. [Means for solving the problem]

[0008] In other words, the turbidity measuring device according to the present invention comprises a cell having a measuring space formed between a light source and a photodetector for containing a liquid to be measured, an incident window for guiding light from the light source into the measuring space, and an exit window for guiding light from the measuring space to the photodetector, and a cleaning mechanism for cleaning the incident window and the exit window, wherein the cleaning mechanism comprises a cleaning body for cleaning the incident window and the exit window, and a drive unit provided outside the measuring space for retracting the cleaning body to the outside of the measuring space during measurement and for moving the cleaning body into the measuring space during cleaning, wherein the cleaning body is rotated around a predetermined central axis by the drive unit, and the central axis is provided outside the measuring space.

[0009] According to this turbidity measuring device, a drive unit is provided outside the measuring space to retract the cleaning body to the outside of the measuring space during measurement and to move the cleaning body into the measuring space during cleaning. Furthermore, since the central axis is provided outside the measuring space, the size of the measuring space can be reduced compared to when the cleaning body is always placed inside the measuring space. As a result, the optical path length, which is the distance between the light source and the photodetector arranged on either side of the measuring space, can be shortened compared to conventional devices.

[0010] A specific embodiment of the present invention is one in which the cell further has a communication space that communicates with the measurement space, and the cleaning body is retracted into the communication space.

[0011] The measurement space may be formed from a first surface and a second surface facing each other, and a third surface connecting the first surface and the second surface, with the incident window formed on the first surface, the transmitted light emission window for measuring transmitted light formed on the second surface, and the scattered light emission window for measuring scattered light formed on the third surface.

[0012] If the cleaning body enters the measurement space and comes into contact with the entrance window, the transmitted light exit window, and the scattered light exit window, then the drive unit can clean all of these windows by driving the cleaning body just once.

[0013] If the cell has an inlet for introducing the liquid to be measured and an outlet for discharging the liquid to be measured from the inside, and the inlet is positioned below the measurement space and the outlet is positioned above the measurement space, then even if foreign matter or bubbles are present in the liquid to be measured, the accumulation of foreign matter or bubbles in the measurement space can be minimized.

[0014] In order to further reduce the influence of foreign matter and air bubbles contained in the liquid being measured, it is preferable that the measurement space is open at the top and bottom, and that the third surface is provided parallel to the vertical direction.

[0015] Specific embodiments of the present invention include a configuration in which the communication space is formed to surround the openings of the measurement space other than the first, second, and third surfaces, and the inlet and outlet are formed in the communication space.

[0016] If the window member forming the incident window is integrally formed with a lens that focuses light from the light source into the cell, it saves space compared to placing a separate lens between the light source and the incident window. [Effects of the Invention]

[0017] According to the present invention, a drive unit is provided outside the measurement space, which retracts the cleaning body outside the measurement space during measurement and moves the cleaning body into the measurement space during cleaning. Further, since the central axis is provided outside the measurement space, the size of the measurement space can be made smaller compared to the case where the cleaning body is always arranged inside the measurement space. As a result, the optical path length, which is the distance between the light source and the photodetector arranged sandwiching the measurement space, can be made shorter than before.

Brief Description of the Drawings

[0018] [Figure 1] Schematic diagram showing the overall structure of a water quality monitor for an exhaust gas purification device provided with a turbidity measurement device according to an embodiment of the present invention. [Figure 2] Schematic diagram showing the entire turbidity measurement device according to this embodiment. [Figure 3] Schematic diagram showing the structure near the cell of the turbidity measurement device according to this embodiment. [Figure 4] Schematic diagram showing the internal structure of the cell of the turbidity measurement device according to this embodiment. [Figure 5] Schematic diagram showing the internal structure of the cell of the turbidity measurement device according to this embodiment. [Figure 6] Schematic diagram showing the structure of the cleaning mechanism provided in the turbidity measurement device according to this embodiment. [Figure 7] Schematic diagram showing the structure of the cleaning mechanism provided in the turbidity measurement device according to this embodiment. [Figure 8] Schematic diagram showing the structure of the cleaning mechanism provided in the turbidity measurement device according to this embodiment. [Figure 9] Schematic diagram showing a turbidity measurement device according to another embodiment of the present invention.

Explanation of Reference Numerals

[0019] 100 ··· Turbidity measurement device 1 ··· Turbidimeter 11 ··· Cell 11a ··· Measurement space 11a1 ··· Incident surface (first surface) 11a2...Transmitted light exit surface (second surface) 11a3...Scattered light output surface (3rd surface) 11b...Communication space 11d ···Inlet 11e... Outlet 121...Light source 12a ···Induction window 122 ···Incident window forming member 13 ···Transmitted light detection unit 13a ···Transmitted light emission window 14 ···Scattered light detection unit 14a ···Scattered light emission window 4. Cleaning mechanism 41 ···Cleaning section 411 ··· Cleaning body 42 ···Drive unit X...center axis [Modes for carrying out the invention]

[0020] One embodiment of the present invention will be described below with reference to the drawings. The turbidity measuring device 100 according to this embodiment continuously measures and monitors the turbidity of wastewater discharged from, for example, homes, factories, ships, etc., and is installed, for example, in a water quality monitor for exhaust gas purification equipment on a ship. This exhaust gas purification system water quality monitor, as shown in Figure 1, for example, comprises a flow path through which the wastewater to be monitored flows, a continuous defoaming device positioned on this flow path to perform defoaming treatment on the wastewater, a PAH sensor for measuring the concentration of polycyclic aromatic hydrocarbons (PAHs) in the wastewater, a pH sensor for monitoring the pH of the wastewater, a turbidity measuring device 100, and a display unit for displaying the output values ​​from these various sensors.

[0021] As shown in Figure 2, the turbidity measuring device 100 according to this embodiment comprises a turbidimeter 1 for measuring the turbidity of wastewater to be measured, a calculation unit 2 for calculating turbidity based on the output signal output from the turbidimeter 1, and an output unit 3 for outputting the turbidity calculated by the calculation unit 2.

[0022] As shown in Figure 3, for example, the turbidimeter 1 comprises a cell 11 connected to a channel through which wastewater flows and containing the wastewater inside, a light source unit 12 that emits light to the wastewater inside the cell 11, a transmitted light detection unit 13 that detects transmitted light emitted from the light source unit 12 and transmitted through the wastewater inside the cell 11, and a scattered light detection unit 14 that detects scattered light scattered by the wastewater inside the cell 11.

[0023] The light source unit 12 includes, for example, a light source 121 such as an LED, and an incident window forming member 122 that forms an incident window 12a for injecting light emitted from the light source 121 into the cell 11. The wavelength of the light emitted from the light source 121 can be appropriately changed for each measurement target to find the optimal wavelength for measuring scattered and transmitted light.

[0024] The transmitted light detection unit 13 is, for example, positioned opposite the light source unit 12 across the cell 11, and comprises, for example, a photodiode which is a transmitted light detector 131, and a transmitted light emission window member 132 which forms a transmitted light emission window 13a that emits light from the measurement space toward the detector from inside the cell 11.

[0025] The scattered light detection unit 14 detects scattered light that has been scattered at a predetermined angle relative to the optical path of light emitted from the light source unit 12, and includes, for example, a photodiode which is a scattered light detector 141, and a scattered light emission window 14a which forms a scattered light emission window 14a that emits light from inside the cell 11 toward the scattered light detector 141. In this embodiment, 90° is adopted as the predetermined angle.

[0026] The calculation unit 2 calculates transmitted turbidity based on the transmitted light detection value output from the transmitted light detection unit 13 and scattered turbidity based on the scattered light detection value output from the scattered light detection unit 14. Specifically, this calculation unit 2 is an information processing circuit that includes a digital circuit consisting of a CPU, memory, and communication ports, an analog circuit equipped with buffers and amplifiers, and an AD converter, DA converter, etc., that mediates between these digital and analog circuits. The CPU and its peripheral devices cooperate according to a predetermined program stored in the memory, and this information processing circuit performs its function as the calculation unit 2.

[0027] Output unit 3 outputs either the scattered turbidity and / or transmitted turbidity calculated by calculation unit 2, and is a display unit that displays the scattered turbidity and / or transmitted turbidity as numerical values ​​or graphs. In this embodiment, this display unit is the display unit of the exhaust gas purification system water quality monitor mentioned above. The system may further include a switching unit that switches the output value output from the output unit 3 between scattered turbidity and transmitted turbidity.

[0028] The switching unit switches the output value output from the output unit 3 between scattered turbidity and transmitted turbidity based on a switching index value, which is, for example, the ratio of the scattered detection value to the transmitted detection value. This switching unit is performed by the information processing circuit described above, and the CPU and its peripheral devices may work together according to a predetermined program stored in the memory to perform the function of the switching unit. The switching index value may be determined, for example, based on the ratio of the scattered detection value to the transmitted detection value (e.g., scattered detection value / transmitted detection value). A predetermined threshold may be set for this switching index value, and the switching unit may switch the output value output from the output unit 3 to transmitted turbidity if it determines that the switching index value exceeds the threshold, and to scattered turbidity if it determines that the switching index value is below the threshold. For example, in the case of dark-colored wastewater containing colored impurities such as black (hereinafter also referred to as dark-colored wastewater), the correlation between the detected value of scattered light measurement and turbidity deteriorates as the concentration of colored impurities increases, making accurate turbidity measurement difficult. Therefore, when the turbidity exceeds a predetermined value (e.g., 40 degrees), it is considered more practical to use transmitted light measurement instead of scattered light measurement.

[0029] However, the turbidity measuring device 100 according to this embodiment is equipped with a cleaning mechanism 4 for cleaning the inner surface of the cell 11. As shown in Figures 3 and 4, the turbidity measuring device 100 according to this embodiment also has distinctive features in the shape of the cell 11, so we will first explain the cell 11. The cell 11 of the turbidity measuring device 100 according to this embodiment is formed between the light source unit 12, the transmitted light detection unit 13, and the scattered light detection unit 14, and has a measuring space 11a for containing the liquid to be measured and a communicating space 11b that communicates with the measuring space 11a.

[0030] The measurement space 11a is a space formed by an incident surface 11a1 (also called the first surface) into which light from the light source is incident, a transmitted light emission surface 11a2 (also called the second surface) into which light incident from the incident surface 11a1 and transmitted through the liquid to be measured is emitted toward the transmitted light detection unit 13, and a scattered light emission surface 11a3 (also called the third surface) into which light incident from the incident surface 11a1 and scattered by the liquid to be measured is emitted toward the scattered light detection unit 14.

[0031] The aforementioned incident window 12a is formed on the incident surface 11a1. Furthermore, the transmitted light emission surface 11a2 has the aforementioned transmitted light emission window 13a, and the scattered light emission surface 11a3 has the aforementioned scattered light emission window 14a.

[0032] In this embodiment, the incident window forming member 122 that forms the incident window 12a is integrally formed with a lens so that it also functions as a lens that focuses light from the light source. Specifically, as shown in Figure 4A, a part of the incident window forming member 122 is a curved surface 122a that functions as a lens. As shown in Figure 4A, the incident window forming member 122 is positioned to be pressed against a plate member 123 arranged around the light source 121 and a retaining member 124 made of brass or the like, which is fixed to the plate member 123 by screwing it in. The plate member 123 is secured at three points to the substrate 121a to which the light source 121 is attached, thereby stably supporting the incident window forming member 122.

[0033] The incident surface 11a1 and the transmitted light emission surface 11a2 are arranged to face each other. In this embodiment, the incident surface 11a1 and the transmitted light emission surface 11a2 are provided to face each other so as to be parallel to each other.

[0034] Furthermore, in this embodiment, the scattered light emission surface 11a3 is positioned perpendicular to the incident surface 11a1 and the transmitted light emission surface 11a2, since the scattered light detection unit 14 detects 90° scattered light. In this embodiment, the incident surface 11a1, the transmitted light emission surface 11a2, and the scattered light emission surface 11a3 are arranged parallel to each other in the vertical direction, and the measurement space 11a opens in the vertical direction.

[0035] In this embodiment, the measurement space 11a is formed only by the incident surface 11a1, the transmitted light emission surface 11a2, and the scattered light emission surface 11a3, and the sides other than the three sides on which these three surfaces are located are openings 11c.

[0036] The communication space 11b communicates with the measurement space 11a through the opening 11c and is formed to surround the measurement space 11a from all sides.

[0037] This communication space 11b has an inlet 11d for introducing the liquid to be measured into the cell 11 and an outlet 11e for discharging the liquid to be measured from the cell 11.

[0038] The inlet 11d is formed vertically below the measurement space 11a, and the outlet 11e is formed above both the inlet 11d and the measurement space 11a.

[0039] As shown in Figure 5, a protrusion 111 is formed inside cell 11, where the inner surface of cell 11 facing the inlet 11d protrudes toward the inlet 11d. Due to the formation of this protrusion 111, the liquid to be measured that flows into the communication space 11b from the inlet 11d collides with the protrusion 111, creating turbulence, and flows toward the measurement space 11a and outlet 11e without stagnating.

[0040] Next, we will explain the cleaning mechanism 4. The cleaning mechanism 4, for example, cleans the entrance window 12a, the transmitted light exit window 13a, and the scattered light exit window 14a of the inner surface of the cell 11 as described above. As shown in Figures 3 and 6, it comprises a cleaning unit 41 that wipes away dirt adhering to the surfaces of the entrance window 12a, the transmitted light exit window 13a, and the scattered light exit window 14a by contacting them, and a drive unit 42 that drives the cleaning unit 41.

[0041] The cleaning unit 41 comprises, for example, a cleaning body 411 such as a plate-shaped wiper made of a resin such as nitrile rubber, and a holding unit 412 that holds the cleaning body 411.

[0042] The shape of the cleaning body 411 is a T-shape with protrusions in three directions, as shown in Figures 3 and 6, for example, so that when the cleaning body 411 is inside the measurement space 11a, it can come into contact with the surfaces of the incident window 12a, the transmitted light emission window 13a, and the scattered light emission window 14a almost simultaneously and clean them all at once.

[0043] The holding portion 412 holds the aforementioned cleaning body 411, for example, by sandwiching it from both sides, and connects to the drive portion 42. For example, its overall shape is a rectangular prism. The thickness and length of the holding portion 412 are such that when the cleaning body 411 enters the measurement space 11a, the tip of the cleaning body 411 can contact the surfaces of the incident window 12a, the transmitted light emission window 13a, and the scattered light emission window 14a.

[0044] As shown in Figures 3 and 5-7, the drive unit 42 is located outside the measurement space 11a and drives the cleaning body 411 of the cleaning unit 41 to retract outside the measurement space 11a during measurement and to enter the measurement space 11a during cleaning. In this embodiment, the drive unit 42 includes a rotating unit 421 that rotates the cleaning unit 41 around a predetermined central axis X, a motor unit 422 that provides driving force to the rotating unit 421, and a drive control unit (not shown) that controls the operation of the motor unit 422. The function of the drive control unit may be handled by the information processing circuit described above.

[0045] A predetermined central axis X is provided outside the measurement space 11a. This central axis X only needs to be set so as not to intersect with the measurement space 11a. As an example, in this embodiment, the central axis X is provided perpendicular to the incident surface 11a1 and the transmitted light emission surface 11a2, and rotates the cleaning unit 41 in a direction parallel to these incident surface 11a1 and transmitted light emission surface 11a2. More specifically, the central axis X in this embodiment is perpendicular to the vertical direction, perpendicular to the incident surface 11a1 and the transmitted light emission surface 11a2, and set parallel to the scattered light emission surface 11a3.

[0046] In this specification, "measurement time" refers to the period during which the transmitted light detection unit 13 or scattered light detection unit 14 detects the transmitted light detection value or scattered light detection value used by the calculation unit 2 to calculate turbidity. "Cleaning time" refers to the period during which the cleaning body 411 is immersed in the measurement space 11a. Preferably, the measurement time and cleaning time are set as separate periods, but they may overlap to some extent.

[0047] Preferably, the rotating part 421 rotates the cleaning part 41 in a certain direction so as to wipe the surfaces of the entrance window 12a, the transmitted light emission window 13a, and the scattered light emission window 14a from bottom to top.

[0048] In this embodiment, the cleaning unit 41 is designed to be removable from the drive unit 42 and replaceable in case the cleaning body 411 deteriorates or for other reasons. The rotating part 421 is provided with a joint J for attaching the holding part 412 that holds the cleaning body 411. The joint J has one or more mounting guides, such as protrusions, formed on it, which serve as markers for confirming how to attach the holding part 412 by touch. Specifically, as shown in Figure 8, for example, a joint J may have a projection T formed on one surface as an attachment guide. By pre-determining the position of this projection T and the attachment orientation of the retaining part 412, even if the inside of the cell 11 is dark and difficult to see, the user can attach the retaining part 412 in the desired orientation by checking the position of the projection T. Alternatively, a recess C for accommodating the aforementioned projection T may be formed on the retaining part 412 side, so that when the retaining part 412 is attached to the joint J, the projection T and the recess C engage, creating a click sensation when the retaining part 412 is attached to the joint J.

[0049] The following are examples of procedures and methods for cleaning the inner surface of the cell 11 using the turbidity measuring device 100 configured in this way, with the cleaning mechanism 4. During measurement, when the liquid to be measured contained in the measurement space 11a is being measured, the drive unit 42 of the cleaning mechanism 4 is set to stop the cleaning body 411 of the cleaning unit 41 at a position opposite to the measurement space 11a, as shown in Figures 3, 5, and 7.

[0050] After the measurement is completed, the motor unit 422 applies torque to the rotating unit 421 so that the cleaning body 411 enters the measurement space 11a as quickly as possible, causing the cleaning unit 411 to rotate, for example, once, around the aforementioned central axis X so that it enters the measurement space 11a from the bottom of the opening 11c of the measurement space 11a and exits into the communication space 11b from the top of the opening 11c of the measurement space 11a. At this time, the tip of the cleaning body 411, which is positioned at the tip of the cleaning unit 41 that has entered the measurement space 11a, comes into contact with the incident window 12a, the transmitted light emission window 13a, and the scattered light emission window 14a, respectively, to wipe away dirt from their surfaces.

[0051] With the turbidity measuring device 100 configured in this way, a measuring space 11a and a communication space 11b surrounding the measuring space 11a are provided inside the cell 11, and the entire cleaning mechanism 4 is positioned inside the communication space 11b during measurement. Therefore, compared to conventional turbidity measuring devices in which only the measuring space 11a is provided inside the cell and part of the cleaning and driving parts are positioned inside it, the size of the measuring space 11a can be reduced. As a result, even with a cleaning mechanism 4 that cleans the entrance window 12a and the exit windows 13a and 14a, the optical path length formed between the entrance window 12a and the exit windows 13a and 14a can be made as short as possible.

[0052] The cleaning body 411 is shaped to contact all three windows: the entrance window 12a, the transmitted light exit window 13a, and the scattered light exit window 14a. The drive unit 42 can clean all three windows at once by simply rotating the cleaning unit 41 once, thus allowing the entrance window 12a, the transmitted light exit window 13a, and the scattered light exit window 14a to be cleaned in the shortest possible time. Therefore, even when continuously measuring the liquid being measured as it flows into the cell 11, it is possible to continue measuring without stopping the measurement to clean the entrance window 12a, the transmitted light exit window 13a, and the scattered light exit window 14a, while cleaning these windows in between measurements. The effectiveness of this embodiment is particularly evident when the interval between measurements needs to be within tens of seconds, such as when measuring the turbidity of ship wastewater.

[0053] An inlet 11d for introducing the liquid to be measured into cell 11 and an outlet 11e for discharging the liquid to be measured from cell 11 are formed in the communication space 11b. Since the inlet 11d is formed below the measurement space 11a and the outlet 11e is formed above the measurement space 11a, even if foreign matter is mixed in the liquid to be measured, it is possible to avoid as much as possible the accumulation of foreign matter in the measurement space 11a. Also, even if air bubbles are mixed in the liquid to be measured, the air bubbles are less likely to remain in the measurement space 11a, so the measurement accuracy can be further improved.

[0054] Since the measurement space 11a opens in the vertical direction, and the scattered light emission surface 142 is also arranged parallel to the vertical direction, the structure is designed to make it less likely for foreign matter and air bubbles to accumulate in the measurement space 11a.

[0055] Since the cell 11 has a protrusion 111 that extends outward from the inlet 11d, the liquid to be measured that flows into the cell 11 from the inlet 11d collides with the protrusion 111, creating turbulence, which helps to minimize the stagnation of the liquid to be measured inside the cell 11.

[0056] Since the central axis X when rotating the cleaning unit 41 is perpendicular to the incident surface 11a1 and the transmitted light emission surface 11a2 that form the measurement space 11a, that is, parallel to the optical path of transmitted light and the scattered light emission surface 11a3 formed between the incident surface 11a1 and the transmitted light emission surface 11a2, the shape of the cleaning unit 41 can be made as simple as possible.

[0057] Since the drive unit 42 rotates the cleaning unit 41 from the lower side to the upper side of the measurement space 11a, the dirt can be discharged towards the outlet 11e which is formed above the measurement space 11a. During measurement, the cleaning body 411 is positioned on the opposite side from the side where the measurement space 11a is formed within the communication space 11b. This is preferable because it does not obstruct the flow of the liquid to be measured into the measurement space 11a, compared to the case where the cleaning unit 41 is located below the measurement space 11a.

[0058] Since the incident window forming member 122 that forms the incident window 12a is integrally formed with the lens, space can be saved compared to when a separate lens is placed between the light source 121 and the incident window forming member 122. In addition, since the incident window forming member 122 only needs to be fixed to the substrate 121a of the light source 121, the trouble of separately positioning the lens relative to the light source 121 can be eliminated. In this embodiment, the plate member 123 that fixes the incident window forming member 122 is fixed at three points, and a lens retainer 124 made of brass is also provided, so that displacement of the incident window forming member 122 can be suppressed as much as possible.

[0059] The present invention is not limited to the embodiments described above. For example, the shape of the cleaning body is not limited to those described above. Also, the cleaning body is not limited to contacting the entrance window, transmitted light exit window, and scattered light exit window almost simultaneously; it may contact them with a slight offset, or it may clean the entrance window, transmitted light exit window, and scattered light exit window separately by driving the cleaning unit multiple times while changing its orientation.

[0060] The cleaning mechanism does not necessarily have to have a rotating part; for example, it may have a sliding part, and the cleaning part may be slid along a pre-installed rail or the like to be sent into the measurement space.

[0061] In the embodiments described above, a case was explained in which both a transmitted light detection unit and a scattered light detection unit are provided. However, it is also possible to provide only a transmitted light detection unit, or only a scattered light detection unit, etc. Furthermore, the scattered light detection unit may detect scattered light other than 90-degree scattered light.

[0062] The measurement space only needs to have an opening into which the cleaning body enters the measurement space, and is not limited to openings in the vertical direction; it may also have a shape where only the sides are open.

[0063] The aforementioned central axis only needs to be positioned so that the rotating part rotates the cleaning part, allowing the cleaning part to enter the measurement space and clean the incident window, transmitted light emission window, and / or scattered light emission window. For example, as shown in Figure 9, if the cleaning part is attached to the rotating part at an angle to the central axis, the central axis may be positioned at an angle to the opening formed in the measurement space. It goes without saying that the effects of the present invention can be achieved even if the central axis is positioned at an angle other than the angle shown in Figure 9. Furthermore, the central axis may intersect the interior of the measurement space, as long as the rotating part rotates the cleaning part, allowing the cleaning part to enter the measurement space and clean the incident window, transmitted light emission window, and / or scattered light emission window. Other modifications are possible as long as they do not contradict the spirit of the present invention. [Industrial applicability]

[0064] According to the present invention, it is possible to provide a turbidity measuring device that has a shorter optical path length than conventional devices, while still being equipped with a cleaning mechanism that includes a cleaning body for cleaning the entrance window and the exit window.

Claims

1. It has a measurement space formed between the light source and the photodetector that contains the liquid to be measured, A cell having an input window that guides light from the light source into the measurement space and an output window that guides light from the measurement space into the photodetector, The system includes a cleaning mechanism for cleaning the injection window and the output window. The measurement space is formed by the first, second, and third surfaces on which the incident window or the exit window is formed. The cleaning mechanism is A cleaning body for cleaning the entrance window and the exit window, It has a drive unit located outside the measurement space, which moves the cleaning body outside the measurement space during measurement and moves the cleaning body into the measurement space during cleaning, The cleaning body is rotated around a predetermined central axis by the drive unit, With the cleaning body inside the measurement space, the first surface, the second surface, and the third surface are cleaned by a single drive by the drive unit. A turbidity measuring device characterized in that the central axis is located outside the measurement space.

2. It further has a communication space that communicates with the aforementioned measurement space, The turbidity measuring device according to claim 1, wherein the cleaning body is retracted into the communication space.

3. The measurement space is formed from a first surface and a second surface that face each other, and a third surface that connects the first surface and the second surface. The first surface has an incident window formed thereon, and the second surface has a transmitted light emission window for measuring transmitted light, The turbidity measuring device according to claim 1 or 2, wherein a scattered light emission window for measuring scattered light is formed on the third surface.

4. The turbidity measuring apparatus according to claim 3, wherein the cleaning body enters the measurement space and comes into contact with the entrance window, the transmitted light exit window, and the scattered light exit window to clean them.

5. The turbidity measuring device according to claim 4, wherein the cleaning body has a shape that protrudes in three directions so that it can contact and clean the surfaces of the entrance window, the transmitted light exit window, and the scattered light exit window.

6. The cell has an inlet for introducing the liquid to be measured into the interior and an outlet for discharging the liquid to be measured from the interior, The aforementioned inlet is located below the measurement space, The turbidity measuring device according to any one of claims 1 to 5, characterized in that the outlet is positioned above the measurement space.

7. The turbidity measuring device according to claim 3, wherein the measurement space is open in the vertical direction and the third surface is provided parallel to the vertical direction.

8. The communication space is formed to surround the openings of the measurement space other than the first, second, and third surfaces, The turbidity measuring device according to claim 3, relating to claim 2, wherein the cell has an inlet for introducing a liquid to be measured into the interior and an outlet for discharging the liquid to be measured from the interior, and the inlet and the outlet are formed in the communication space.

9. The turbidity measuring device according to any one of claims 1 to 8, wherein the window member forming the incident window is integrally formed with a lens that focuses light from the light source into the cell.

10. The turbidity measuring device according to any one of claims 1 to 9, wherein the liquid to be measured is wastewater discharged from a ship.

Images