Residual chlorine meter

Abstract

Increase measurement accuracy. [Solution] The residual chlorine meter comprises a sensor body having a lower end that can be immersed in the measurement fluid during measurement, the sensor body having a measurement space at the lower end connected to the outside through an opening, an intake port at the lower end, a pump chamber that introduces the measurement fluid through the intake port, an impeller that is provided in the pump chamber and driven to rotate, an outlet facing the measurement space and discharging the measurement fluid introduced into the pump chamber into the measurement space, and a discharge flow path that connects the pump chamber and the discharge port, a drive mechanism that drives the impeller to rotate, and a sensor head that has an electrode facing the outlet port in the measurement space and that comes into contact with the measurement fluid to output an oxidation / reduction current based on the concentration of free residual chlorine contained in the measurement fluid, and the discharge flow path of the pump mechanism extends diagonally upward in a straight line from the pump chamber toward the electrode during measurement.

Description

[Technical Field]

[0001] The present invention relates to a residual chlorine meter. [Background technology]

[0002] One known reagentless method for measuring the concentration of free residual chlorine is the polarographic method (polarography). The polarographic method measures the oxidation-reduction current that flows between two electrodes (a counter electrode and a working electrode) when a voltage (measurement voltage) is applied between the two electrodes immersed in the test water. This allows the ion concentration of a specific chemical species to be measured.

[0003] Three-electrode polarographic methods are also known, which use a reference electrode (standard electrode) in addition to a counter electrode and a working electrode. In a three-electrode method, a reference potential is applied to the reference electrode to determine the potential of the working electrode, whose absolute potential is unknown. This three-electrode polarographic method has the advantage of being resistant to changes in conductivity and allowing for the electrodes to be made smaller. In polarographic methods, the oxidation-reduction current value changes when the flow rate of the test water in contact with the electrodes changes, so the electrodes must be in contact with the test water at a constant flow rate.

[0004] An amperometric sensor system (see, for example, Patent Document 1) is known as an installed residual chlorine meter using this polarographic method. In this system, a sensor housing containing a chlorine sensor and a pH sensor is directly inserted into a joint or the like of a water distribution pipe. Test water is supplied to the electrodes of each sensor at a constant flow rate by a pump with an impeller driven by a magnetic coupling.

[0005] Also known as a portable residual chlorine meter using the Galvanic method, which is different from the polarographic method, is a residual chlorine measuring instrument (see, for example, Patent Document 2). The Galvanic method measures the oxidation-reduction current that flows between two electrodes without applying a voltage. In this residual chlorine measuring instrument, an impeller attached to a shaft that is directly connected to a motor and extends into a pump chamber is rotated, and the test water is transported from the pump chamber to a tube equipped with a residual chlorine concentration detection unit having a pair of electrode plates, and measurement is performed.

[0006] Furthermore, a portable residual chlorine meter (see, for example, Patent Document 3) is known in which, as a preparation stage, a calibration coefficient is calculated using data for calculating the calibration coefficient based on the pre-calibration residual chlorine reaction amount of the test water and the calibration standard residual chlorine standard concentration, and, as a measurement stage, the calibrated residual chlorine concentration of the test water is calculated using data for calculating the calibrated residual chlorine concentration based on the residual chlorine reaction amount of the test water at the time of measurement and the calibration coefficient. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent Application Publication No. 2018 / 0143152 [Patent Document 2] Japanese Utility Model Application Publication No. 61-178461 [Patent Document 3] Patent No. 4377197 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the system disclosed in Patent Document 1 has a complex water flow and uses cleaning beads, which can cause adverse effects on the water flow, such as water reflection, making it difficult to improve measurement accuracy.

[0009] Furthermore, the measuring device disclosed in Patent Document 2 also requires the water flow to bend by 90 degrees, which causes reflection of the water and adversely affects the water flow, making it difficult to improve measurement accuracy.

[0010] Furthermore, in the residual chlorine meter disclosed in Patent Document 3, the sensor of the sensor unit needs to be immersed in the test water and stirred while performing the measurement, which results in a problem that the measurement accuracy is prone to fluctuate and it is not possible to perform the measurement while maintaining a stable high measurement accuracy.

[0011] The present invention has been made in view of the above circumstances, and has an object to provide a residual chlorine meter with high measurement accuracy. [Means for solving the problem]

[0012] The residual chlorine meter according to the present invention comprises a sensor body having a lower end that can be immersed in the measurement fluid during measurement, the sensor body comprising a measurement space provided on a side surface of the lower end and connected to the outside through an opening, a suction port provided at the lower end, a pump chamber into which the measurement fluid is introduced through the suction port, an impeller provided in the pump chamber and driven to rotate, an outlet facing the measurement space and discharging the measurement fluid introduced into the pump chamber into the measurement space, and a discharge flow path connecting the pump chamber and the discharge port, a drive mechanism for driving the impeller to rotate, and a sensor head having an electrode facing the outlet port in the measurement space, which comes into contact with the measurement fluid and outputs an oxidation-reduction current based on the concentration of free residual chlorine contained in the measurement fluid, and the discharge flow path of the pump mechanism extends diagonally upward in a straight line from the pump chamber toward the electrode during measurement.

[0013] In one embodiment of the present invention, the discharge flow path of the pump mechanism extends obliquely upward in a straight line from an intersection with a discharge-side tangent to the rotational orbit of the impeller toward the electrode surface of the electrode during the measurement.

[0014] In another embodiment of the present invention, the sensor body has a case member formed in a cylindrical shape extending in the vertical direction and having the opening, the pump mechanism is detachably attached to the lower end side of the case member and has a pump head in which the suction port, the pump chamber, the discharge flow path, and the discharge port are formed, and the drive mechanism is housed in the case member and has a driven member provided at the base of the impeller, a drive member arranged opposite the driven member in the direction of the rotational axis of the impeller and magnetically connected to the driven member to rotate the impeller, and a drive motor that rotates the drive member.

[0015] In yet another embodiment of the present invention, the sensor head includes a first columnar section, a second columnar section provided at one end of the first columnar section and having a smaller diameter than the first columnar section, a counter electrode and a reference electrode arranged parallel to a side surface of the first columnar section, and multiple working electrodes arranged at a tip of the second columnar section, and the discharge flow path of the pump mechanism extends from the pump chamber toward the multiple working electrodes. [Effects of the Invention]

[0016] According to the present invention, it is possible to improve the measurement accuracy. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view showing the appearance of a residual chlorine meter according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the sensor body of the residual chlorine meter. [Figure 3] FIG. 2 is a perspective view showing the configuration of a pump mechanism and a sensor head with a portion of the lower end of the sensor main body cut away. [Figure 4] FIG. 2 is a view showing a lower end portion of the sensor main body with a portion thereof cut away. [Figure 5] FIG. 2 is a perspective view showing the pump head removed from the case member. [Figure 6] FIG. 2 is a perspective view of the impeller and its surroundings, with a portion cut away. [Figure 7]FIG. 2 is a cross-sectional view of an impeller and a portion of its periphery. [Figure 8] FIG. [Figure 9] FIG. 2 is a perspective view showing the appearance of a sensor head. [Figure 10] FIG. 2 is a block diagram for explaining a measurement circuit inside the controller. [Figure 11] 10 is a diagram for explaining the connection state of the sensor main body and the controller during measurement. FIG. [Figure 12] 10 is a diagram for explaining the connection state of the sensor main body and the controller when stored. FIG. [Figure 13] 10A and 10B are diagrams illustrating examples of applied voltage and measured current in air / water detection. [Figure 14] FIG. 2 is a perspective view for explaining the submerged area of the sensor body and the air storage area (air barrier area). [Figure 15] 10A and 10B are diagrams illustrating modified examples of the impeller of the pump mechanism in the sensor main body. [Figure 16] 10A and 10B are diagrams for explaining the discharge of air bubbles by the impeller. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a residual chlorine meter according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments do not limit the invention according to each claim, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0019] In the following embodiments, the same or corresponding components are denoted by the same reference numerals, and redundant explanations are omitted. In the embodiments, the arrangement, scale, dimensions, etc. of each component may be exaggerated or minimized, and may not correspond to the actual ones, and some components may be omitted.

[0020] [Configuration of the residual chlorine meter of the first embodiment] Fig. 1 is a perspective view showing the appearance of a residual chlorine meter according to a first embodiment of the present invention. Fig. 2 is an exploded perspective view of a sensor body of this residual chlorine meter. Fig. 1(a) shows the appearance of the residual chlorine meter as seen from above, and Fig. 1(b) shows the appearance of the sensor body as seen from above at a different angle.

[0021] As shown in Fig. 1(a), the residual chlorine meter 100 according to this embodiment includes a sensor body 10 and a controller 20. The sensor body 10 is used, for example, during measurement with its longitudinal direction aligned with the vertical direction (up-down direction) so that its lower end is immersed in a measurement fluid (test water) containing chlorine. The controller 20 is provided separately from the sensor body 10 and is detachably attached to the top end of the sensor body 10 during measurement and to a side surface of the sensor body 10 during storage.

[0022] [Configuration of sensor main body 10] The sensor main body 10 includes, for example, a cylindrical case member 11 extending in the vertical direction. The case member 11 is formed, for example, from a resin molded product formed so that the cross section is a chamfered triangular shape, specifically a chamfered isosceles triangle shape. As shown in FIG. 2, the case member 11 has an opening 12 at the bottom end. The case member 11 has an opening 13 in a part of a wall portion 14 near the bottom end. The case member 11 has an internal measurement space 15 that is connected to the outside via the opening 13. In the following description, the side of the case member 11 where the opening 13 is formed will be referred to as the "front side," and the opposite side will be referred to as the "rear side."

[0023] A mark 11b is formed on the side surface of the wall 14 of the case member 11 to indicate the submersion range in which the sensor main body 10 can be immersed in the test water (measurement fluid) from the lower end thereof. As shown in FIG. 1(b), an air outlet 6 is formed on the rear side of the wall 14 below the mark 11b. The air outlet 6 is located at the lower end of an air storage area (hereinafter referred to as the "air barrier area"), which will be described later. Furthermore, a second storage attachment portion 5 having a T-shaped cross section is formed on the wall 14 above the air outlet 6. The second storage attachment portion 5 slides into engagement with a first storage attachment portion 21 formed on the side of the controller 20.

[0024] In addition, at the upper end of the case member 11, there is formed a cable gland 19 to which the cable 29 of the controller 20 is attached, and a plate-shaped second measurement mounting portion 18 inclined at a predetermined angle that slides into engagement with a first measurement mounting portion 22 formed on the rear (back) side of the controller 20.

[0025] 2, the sensor main body 10 is provided with a pump mechanism 50 on the rear side of the lower end, and a sensor head 70 on the front side of the lower end. The sensor main body 10 also is provided with a drive mechanism 60 above the pump mechanism 50 that drives the pump mechanism 50.

[0026] Fig. 3 is a perspective view showing the configuration of the pump mechanism 50 and the sensor head 70, with a portion of the lower end of the sensor main body 10 cut away. Fig. 3(a) is a view of the sensor main body 10 seen from diagonally below, and Fig. 3(b) is a view of the sensor main body 10 seen from diagonally above. Fig. 4 is a view showing the lower end of the sensor main body 10 with a portion cut away. Fig. 4(a) is a view from the front side of the lower end of the sensor main body 10 with a portion cut away shown in Fig. 3, and Fig. 4(b) is a view of the same from the right side.

[0027] [Configuration of pump mechanism 50] As shown in FIGS. 3 and 4, the pump mechanism 50 includes a pump head 30 and an impeller 40 that is attached to the pump head 30 and driven to rotate.

[0028] The pump head 30 is made of, for example, a resin molded product and has a pump chamber 31 formed internally with a circular recess facing upward. The bottom surface of the pump head 30 is provided with an inlet 32 through which the measurement fluid is introduced into the pump chamber 31 from below the sensor body 10. The inlet 32 is formed, for example, with multiple slits to prevent foreign particles in the test water from entering the pump chamber 31. The pump head 30 has a discharge flow path 33 that extends obliquely upward in a straight line from the pump chamber 31 toward the sensor head 70 during measurement, and a discharge port 34 that is the outlet of the discharge flow path 33 on the sensor head 70 side. As shown in FIG. 4( a), the discharge flow path 33 also extends obliquely upward toward the sensor head 70 when viewed from the front. More specifically, the discharge flow path 33 extends obliquely upward in a straight line toward the sensor head 70 during measurement from the intersection (point of intersection) of the rotational path of the impeller 40 and the discharge-side tangent to the rotational path.

[0029] FIG. 5 is a perspective view showing the pump head 30 removed from the case member 11. The pump head 30 is removably attached to the opening 12 at the bottom of the case member 11. Specifically, as shown in FIG. 5, an operating unit 39 with engaging claws 38 is provided on both sides of the underside of the pump head 30, and the pump head 30 is attached to the case member 11 by engaging the engaging claws 38 with engaging holes 14a provided on both sides of the bottom of the case member 11. Pressing the operating unit 39 from both sides disengages the engaging claws 38 from the engaging holes 14a. This eliminates the need for additional fastening parts, such as bolts and nuts, to attach the pump head 30 to the case member 11, reducing the weight and cost of the sensor main body 10 and facilitating the attachment and detachment of the pump head 30.

[0030] Fig. 6 is a perspective view with a portion of the impeller 40 and its periphery cut away. Fig. 7 is a cross-sectional view of the impeller 40 and its periphery. Fig. 7(a) is a front view of the impeller 40 and its periphery in cross section, and Fig. 7(b) is a right side view of the same.

[0031] The impeller 40 has a plurality of blades 43 arranged on the pump chamber 31 side, a base 41 on which the plurality of blades 43 are formed, a driven magnet 61 which is a driven member provided on the base 41, and a lid 42 which fixes the driven magnet 61 to the base 41. The base 41 and the lid 42 of the impeller 40 are made of, for example, a resin molded product. The base 41 of the impeller 40 is formed, for example, in a cylindrical shape. The base 41 and the lid 42 are fixed together by, for example, ultrasonic welding or adhesive bonding.

[0032] The driven magnet 61 built into the base 41 of the impeller 40 is made of, for example, a neodymium magnet formed in an annular shape. The lid 42 of the impeller 40 has a stepped disk-like outer shape. The lid 42 is configured as a stopper that can fix the driven magnet 61 to the base 41.

[0033] The impeller 40 also has, for example, a conical portion 44 provided between the base 41 and the plurality of blades 43. As shown in Figures 7(a) and 7(b), the conical portion 44 plays a role in allowing air (bubbles) 8 generated around the plurality of blades 43 to escape upward along the inclined curved surface.

[0034] The pump mechanism 50 further includes, for example, an impeller support portion 51 that rotatably supports the impeller 40 on the rotation shaft. The impeller 40 is disposed in the pump chamber 31 of the pump head 30 while being rotatably supported on the rotation shaft by the impeller support portion 51.

[0035] Figure 8 shows the impeller support part 51, where Figure 8(a) is an oblique view, Figure 8(b) is a front view of Figure 8(a) seen from the direction of arrow F, Figure 8(c) is a cross-sectional view of Figure 8(b) cut along line AA and seen from the direction of the arrow, Figure 8(d) is an enlarged cross-sectional view of part B in Figure 8(c), Figure 8(e) is a side view of Figure 8(a) seen from the direction of arrow G, and Figure 8(f) is an enlarged view of part C in Figure 8(e).

[0036] 6 to 8, impeller support portion 51 has a cylindrical housing portion 52 that houses drive magnet 62 and one end side of motor shaft 63. Impeller support portion 51 also has a disk-shaped support member 53 provided on the tip side of housing portion 52. Impeller support portion 51 also has a hook-shaped arm member 54 that extends from the outer periphery side of support member 53 along the rotational axis direction of impeller 40 and has a tip side that is bent in a direction intersecting the rotational axis direction.

[0037] A major portion of this impeller support part 51 is disposed within the measurement space 15 of the case member 11. The accommodation part 52 of the impeller support part 51 is formed in a cylindrical shape and is disposed within the measurement space 15 adjacent to the sensor head 70. A first support protrusion 53a is provided at the center of the support member 53 of the impeller support part 51. A second support protrusion 54a is provided at the tip of the arm member 54. The first support protrusion 53a and the second support protrusion 54a are disposed opposite each other along the rotation axis of the impeller 40.

[0038] Meanwhile, a central recess is formed in each of the engaging protrusion 42a formed in the center of the lid portion 42 of the impeller 40 and the tip portion 45 of the impeller 40. These central recesses engage with the first support protrusion 53a and the second support protrusion 54a, thereby sandwiching the impeller 40 in the direction of the rotation axis and rotatably supporting it. The impeller 40 can be easily attached to and detached from the impeller support portion 51 by utilizing the flexibility of the arm member 54.

[0039] 8(a), the support member 53 of the impeller support part 51 has an air bleed mechanism 55 that discharges upward air that accumulates above the impeller 40. The air bleed mechanism 55 includes at least one (two, in this example) recessed part 53c that widens from the first support protrusion 53a side toward the outer periphery on a surface 53b of the support member 53 that faces the bottom surface (surface of the lid part 42) of the base part 41 of the impeller 40 in the rotational axis direction.

[0040] The air bleed mechanism 55 also includes a slit 53d at the outer peripheral end of the recess 53c, the diameter of which decreases upward from the recess 53c. The recess 53c has a tapered bottom surface 53e that slopes upward from the first support protrusion 53a side toward the outer periphery.

[0041] [Configuration of drive mechanism 60] 2 and 6, the drive mechanism 60 has a driven magnet 61 provided on the base 41 of the impeller 40. The drive mechanism 60 also has a drive magnet 62 arranged opposite to the driven magnet 61 in the direction of the rotation axis of the impeller 40 and connected to the driven magnet 61 in a non-contact manner by magnetic coupling.

[0042] Furthermore, the drive mechanism 60 has a motor shaft 63 connected to the drive magnet 62, and a drive motor 64 connected to the end of the motor shaft 63 opposite to the drive magnet 62, and which drives and rotates the drive magnet 62 via the motor shaft 63. The drive motor 64 is, for example, a DC motor.

[0043] The drive magnet 62 and motor shaft 63 of the drive mechanism 60 constitute a drive member. This drive member and drive motor 64 are housed in the housing space 16 in the upper part of the case member 11, as shown in FIG. 2. The housing space 16 is liquid-tightly separated from the measurement space 15. An opening 11a is formed in the wall 14 of the case member 11 at a position corresponding to the housing space 16. A cover 17 is attached to this opening 11a via a gasket 16a made of various sealing materials such as rubber or elastomer. As a result, the opening 11a is liquid-tightly closed, and the housing space 16 is isolated from the outside.

[0044] This opening 11a serves as an access port for the drive mechanism 60 and the like arranged in the accommodation space 16 of the case member 11 in the sensor main body 10. The cover part 17 is configured to be detachable from the opening 11a, for example, by a locking mechanism having an engagement structure (not shown) for engaging with an engaged part 16b provided in the accommodation space 16.

[0045] [Configuration of sensor head 70] 3 and 4, the sensor head 70 is disposed in the measurement space 15 so as to be exposed from the opening 13 of the case member 11. The electrodes of the sensor head 70 come into contact with the measurement fluid discharged from the pump chamber 31, and output an oxidation-reduction current based on the concentration of free residual chlorine contained in the measurement fluid.

[0046] The sensor head 70 is made of, for example, a resin molded product. The sensor head 70 is detachably attached to a head attachment portion 70a (see FIG. 2) provided on the impeller support portion 51. The sensor head 70 is disposed adjacent to the accommodation portion 52 of the impeller support portion 51 within the measurement space 15.

[0047] Fig. 9 is a perspective view showing the appearance of the sensor head 70. As shown in Fig. 9, the sensor head 70 has, for example, a first columnar section 71 formed in a cylindrical shape and a second columnar section 72 formed in an elliptical cylindrical shape with a smaller diameter than the first columnar section 71. Note that the shapes of the first columnar section 71 and the second columnar section 72 are not limited to these cylindrical and elliptical cylindrical shapes, and various shapes can be adopted.

[0048] The sensor head 70 further includes a temperature sensor 76 for measuring the temperature of the test water, which is disposed adjacent to the second columnar section 72. The sensor head 70 also includes electrodes in contact with the fluid to be measured, such as a counter electrode 73 and a reference electrode (standard electrode) 74 disposed in parallel on the side surface of the first columnar section 71, and multiple working electrodes 75a, 75b disposed at the tip of the second columnar section 72.

[0049] The counter electrode 73 and the reference electrode 74 are each composed of a linear electrode arranged on the opening 13 side of the wall 14 of the case member 11. The counter electrode 73 is made of, for example, gold or platinum. The reference electrode 74 is made of, for example, silver or gold. The multiple working electrodes 75a, 75b each have a circular electrode surface facing the measurement space 15 above the discharge port 34 of the pump head 30. The working electrode 75a is made of, for example, gold. The working electrode 75b is made of, for example, platinum.

[0050] In this way, by using different materials for the multiple working electrodes 75a, 75b, the residual chlorine meter 100 of the first embodiment can accommodate multiple types of chlorine agents in test water. For example, the gold working electrode 75a is suitable for use with test water containing sodium hypochlorite, which has low electrical conductivity and therefore cannot be used with platinum. For this reason, the gold working electrode 75a is used, for example, when measuring the concentration of free residual chlorine in test water containing sodium hypochlorite that is diluted and used as is, acidified and used to increase its disinfecting power, or diluted and used at a high temperature.

[0051] Furthermore, for example, the platinum working electrode 75b is suitable for use with test water such as electrolyzed water, which contains a large amount of salt and would dissolve if gold were used. For this reason, the platinum working electrode 75b is used, for example, as a test water for electrolyzed water (hypochlorous acid water), when measuring the concentration of free residual chlorine in slightly acidic electrolyzed water, weakly acidic electrolyzed water, strongly acidic electrolyzed water, electrolyzed water (alkaline), and electrolyzed water to which an acidic chemical has been added, using hydrochloric acid and sodium chloride as raw materials.

[0052] Other examples of chlorine agents include calcium hypochlorite and sodium dichloroisocyanurate. The working electrodes 75a and 75b are used depending on the chlorine agent of the fluid being measured. The materials of the working electrodes 75a and 75b are not limited to those mentioned above, and various materials can be used. Furthermore, the working electrodes 75a and 75b may each have a structure in which the gold and platinum mentioned above are interchanged.

[0053] The working electrodes 75a and 75b are formed in a flat (disk-like) shape because the measured concentration varies depending on their surface area. On the other hand, the counter electrode 73 and the reference electrode 74 are made of inexpensive wire because their performance does not differ depending on their size as long as the surface area of the counter electrode 73 is not too small. Furthermore, the counter electrode 73 and the reference electrode 74 are provided on the side of the sensor head 70 because they do not need to come into contact with the measurement fluid at a predetermined flow rate.

[0054] [Controller 20 configuration] As shown in Figure 1(a), the controller 20 of the residual chlorine meter 100 of the first embodiment has a case section 28 formed in a shape that can be held in one hand by a user (measurer), a monitor display (hereinafter referred to as the "monitor") 23 provided on the front (surface) side of the case section 28 for displaying various information, and an operation button section 24 for operating the information displayed on the monitor 23, including the operation of the sensor main body 10.

[0055] The monitor 23 of the controller 20 functions as a notification unit capable of notifying various types of information, including information related to the result of the dry water detection described below. The controller 20 may also be equipped with a speaker (not shown) or lamps capable of audio output as the notification unit. The operation button unit 24 of the controller 20 includes various operation buttons, such as a power ON / OFF button, cursor button, enter button, back button, brightness adjustment button, and measurement start button.

[0056] The controller 20 also includes, inside the case 28, a power supply unit (not shown) equipped with a power source such as a dry cell, and a control unit (not shown) that controls the entire sensor body 10, including the operation of the pump mechanism 50 of the sensor body 10 and measurements by the sensor head 70. The control unit of the controller 20 applies a drive voltage (e.g., 1.5 V) from the power supply unit to the drive motor 64 using a voltage application method such as PWM.

[0057] As a result, the drive motor 64 rotates the motor shaft 63 and the drive magnet 62 at a constant rotation speed, and the rotation speed of the impeller 40 via the driven magnet 61 is also constant. Therefore, it is possible to transfer the measurement fluid discharged from the pump chamber 31 through the discharge flow path 33 and the discharge port 34 at a constant flow velocity and flow rate, which are essential for highly stable measurement accuracy.

[0058] FIG. 10 is a block diagram for explaining the measurement circuit inside the controller. As shown in FIG. 10, the control unit of the controller 20 includes, for example, a measurement circuit 80 and an applied voltage generation unit 86. The measurement circuit 80 includes switches 81a and 81b, a current-voltage conversion circuit 82, a voltage amplifier 83, a microcomputer 84, a display unit 23a, and a memory unit 85. For example, if the working electrode 75a of the sensor head 70 is sensor 1 and the working electrode 75b is sensor 2, the switches 81a and 81b connect either sensor 1 or sensor 2 to the current-voltage conversion circuit 82. These switches 81a and 81b are configured, for example, by photoMOS relays. When measurement is stopped, both switches 81a and 81b are turned off.

[0059] The measurement current, which is an oxidation-reduction current from sensor 1 or sensor 2, is converted into a voltage value by current-voltage conversion circuit 82 via switch 81a or switch 81b, amplified by voltage amplifier 83, and input to microcomputer 84. Microcomputer 84 calculates the concentration of free residual chlorine in the measurement fluid based on the input voltage value, and outputs the measurement result indicating the calculated value to display unit 23a and stores it in memory unit 85.

[0060] The display unit 23a controls the display of the monitor 23 to display various information such as the measurement results on the display screen. The measurement results are readably stored in the storage unit 85 for each measurement, for example. This eliminates the need for the user (measurer) to take actions such as writing down the measurement results, thereby further improving convenience.

[0061] The applied voltage generating unit 86 includes a DAC 87 that performs digital / analog conversion of the applied voltage control signal from the microcomputer 84, and a power supply unit that generates an applied voltage (measured) according to the value converted by the DAC 87. The sensor head 70 includes a voltage amplifier 88 that amplifies a voltage (such as a voltage) applied to the counter electrode 73 of the sensor head 70, and a reference voltage generator 89 that generates a reference voltage to be applied to the reference electrode 74. During initial cleaning, the applied voltage generator 86 applies a predetermined pulsed applied voltage (cleaning voltage) for initial cleaning, which is different from the measurement voltage, to the counter electrode 73 of the sensor head 70, for example. The cleaning voltage is applied by repeating pulses of a predetermined duration multiple times, for example. During normal measurement, the applied voltage generator 86 applies a measurement voltage to the counter electrode 73 of the sensor head 70, for example.

[0062] [Connection configuration between sensor main body 10 and controller 20] Fig. 11 is a diagram illustrating the connection state of the sensor main body 10 and the controller 20 during measurement. Fig. 11(a) is a perspective view showing the state of the sensor main body 10 and the controller 20 before connection during measurement, and Fig. 11(b) is a perspective view showing the state of the sensor main body 10 and the controller 20 after connection during measurement. Fig. 12 is a diagram illustrating the connection state of the sensor main body 10 and the controller 20 when stored. Fig. 12(a) is a perspective view showing the state of the sensor main body 10 and the controller 20 before connection during storage, and Fig. 12(b) is a perspective view showing the state of the sensor main body 10 and the controller 20 after connection during storage.

[0063] In the residual chlorine meter 100 of the first embodiment, the sensor body 10 and the controller 20 are configured as separate, detachable components. This not only makes it highly portable, but also provides the following improvements: As shown in Figure 11(a), before the two are connected during measurement, the sensor body 10 and the controller 20 are not integrated.

[0064] Then, second measurement attachment part 18 provided at the upper end of case member 11 of sensor main body 10 and first measurement attachment part 22 formed on the back side of controller 20 are slid into engagement in the direction indicated by the double arrow in the figure. Then, as is clear from the state after the two are connected during measurement, as shown in Figure 11(b), controller 20 is connected and integrated at an angle relative to sensor main body 10 at the upper end side of sensor main body 10, whose longitudinal direction extends vertically.

[0065] Therefore, during measurement, the lower end of the sensor body 10 is immersed vertically in the test water within the submerged range, and the user (measurer) can perform the measurement while holding the controller 20 in one hand, for example, and checking the monitor 23.

[0066] At this time, the opening 13 on the front side of the sensor main body 10 faces the user (measurer), so it is possible to easily check the state of the discharge side of the measurement fluid and perform measurement while, for example, avoiding contact with the liquid. In this way, during measurement, the user (measurer) can use the residual chlorine meter 100 with one hand, so that the user (measurer) can perform measurement while performing other tasks, such as taking notes, with the other hand.

[0067] Therefore, the residual chlorine meter 100 of the first embodiment can easily measure the concentration of free residual chlorine without, for example, needing to fix the sensor body 10 to a flow cell (measurement tank), etc. In this way, the residual chlorine meter 100 can easily perform measurements regardless of the measurement environment, making it extremely convenient.

[0068] On the other hand, as shown in Figure 12(a), before the two are connected during storage, the sensor main body 10 and the controller 20 are not integrated, but the second storage mounting portion 5 provided on the side of the wall portion 14 of the case member 11 of the sensor main body 10 and the first storage mounting portion 21 provided on the side of the controller 20 are slidably engaged in the direction indicated by the double arrow in the figure.

[0069] As a result, as shown in Figure 12(b), as is clear from the state after the two are connected when stored, the controller 20 is connected along the side of the sensor main body 10, lined up next to the sensor main body 10, and integrated with it, on the side of the sensor main body 10, whose longitudinal direction extends in the vertical direction as described above.

[0070] Therefore, when stored, the sensor main body 10 and the controller 20 can be stored compactly as a single integrated device, rather than being separated from each other. This is advantageous in that the residual chlorine meter 100 can be easily carried when transported, and it can be more convenient.

[0071] [Operation of Residual Chlorine Meter 100] Next, the operation of the residual chlorine meter 100 of the first embodiment will be described. First, the user (measurer) sets the sensor main body 10 and controller 20 to the state after connection during measurement shown in Fig. 11(b). Next, while holding the controller 20, the user immerses the submerged area of the sensor main body 10 vertically in the test water and turns the power on by pressing the power on / off button in the operation button section 24 of the controller 20. Next, either one of the working electrodes 75a or 75b is selected using the switches 81a, 81b (Fig. 10).

[0072] [Initial cleaning] FIG. 13 is a diagram showing an example of applied voltage and measured current in air / water detection. When either the working electrode 75a or 75b is selected by the switches 81a and 81b, the working electrode 75a or 75b is initially cleaned before each measurement. The initial cleaning of the electrode is performed by outputting an applied voltage control signal from the microcomputer 84 of the measurement circuit 80 to the applied voltage generator 86, as shown in FIG.

[0073] That is, the applied voltage generating unit 86 performs digital-to-analog conversion of the applied voltage control signal from the microcomputer 84 using a DAC 87, and amplifies the applied voltage (measurement voltage, etc.) from the power supply unit according to the converted value using a voltage amplifier 88. Then, during initial cleaning, the applied voltage generating unit 86 applies a predetermined pulsed cleaning voltage for initial cleaning that is different from the measurement voltage (for example, greater than the measurement voltage) to the counter electrode 73 of the sensor head 70, for example, as shown in Fig. 13. The cleaning voltage is, for example, a pulsed voltage that continues for 10 seconds at a cycle of 0.5 seconds.

[0074] At this time, the sensor current (measurement current) flowing between the counter electrode 73 of the sensor head 70 and one of the working electrodes 75a, 75b is converted into a voltage value by the current-voltage conversion circuit 82 of the measurement circuit 80 as described above, amplified by the voltage amplifier 83, and input to the microcomputer 84. Then, the microcomputer 84 performs threshold determination using, for example, threshold values 1 and 2 as shown in the figure.

[0075] Based on the result of this threshold determination by the microcomputer 84, empty water detection of the sensor head 70 of the sensor main body 10 is performed. That is, by this empty water detection, it is automatically determined whether or not the sensor head 70 is in the test water during initial cleaning before the actual measurement begins. If the current value of the measurement current exceeds either threshold value 1 or 2 (or both) for example a predetermined number of times, the microcomputer 84 determines that the sensor head 70 is in the test water, and continues measurement after the initial cleaning, for example.

[0076] On the other hand, if the current value of the measured current does not exceed both thresholds 1 and 2, for example, for a predetermined number of times, the microcomputer 84 determines that the sensor head 70 is in the air. In this case, the microcomputer 84 may display information on the display screen of the monitor 23 via the display unit 23a, for example, indicating that the sensor head 70 is not in the sample water and therefore cannot perform accurate measurement.

[0077] It should be noted that, for example, if the control unit determines that the sensor head 70 is in the air based on the information on the determination result by the microcomputer 84, it can forcibly stop the rotation of the impeller 40 by the drive mechanism 60. In this way, by stopping the rotation of the impeller 40 when the sensor head 70 is in the air, it is possible to prevent the impeller 40 from spinning idly in the air, which would otherwise be wasted power consumption, and to suppress heat generation due to the operation of the pump mechanism 50 and drive mechanism 60 around the impeller 40, thereby extending the life of the sensor main body 10.

[0078] [Normal measurement] The measurement operation is initiated when the microcomputer 84 determines that the lower end of the sensor body 10 is immersed in the sample water. The concentration of free residual chlorine is measured by applying a measurement voltage to the counter electrode 73 for a predetermined time (e.g., 15 seconds) and detecting an oxidation-reduction current from one of the working electrodes 75a, 75b.

[0079] In this state, when the impeller 40 of the pump mechanism 50 is rotationally driven by the drive mechanism 60, the measurement fluid is introduced from the suction port 32 of the pump head 30 into the pump chamber 31 in the fluid suction direction indicated by the dotted arrow 35 in the figure, as shown in Figure 4. The measurement fluid introduced into the pump chamber 31 passes through the discharge flow path 33 from the pump chamber 31 along the fluid discharge direction indicated by the dotted arrow 36 in the figure due to the rotation of the impeller 40, and is discharged obliquely upward from the discharge port 34 toward the sensor head 70. The measurement fluid discharged from the discharge port 34 comes into contact with the working electrodes 75a, 75b of the sensor head 70 at a predetermined flow rate, and is then discharged outside the measurement space 15 through the opening 13 in the wall 14.

[0080] In this way, in the sensor body 10 of the residual chlorine meter 100, the measurement fluid can be applied to the sensor head 70 at an angle when viewed from the front and side in the measurement space 15, and then directly discharged to the outside from the measurement space 15. This prevents reflection of the measurement fluid, which would affect the measurement of the concentration of free residual chlorine in the test water, and prevents turbulence in the flow of the measurement fluid that contacts the working electrodes 75a, 75b, resulting in a constant, smooth flow.

[0081] 7(a) and 7(b), the air bleed mechanism 55 provided on the support member 53 of the impeller support portion 51 has a function of releasing, within the measurement space 15, air 8 generated around the impeller 40 rotating in the pump chamber 31 above the support member 53. That is, the air 8 generated around the blades 43 of the impeller 40 flows along the inclined curved surface of the conical portion 44 to the upper side of the base 41 and escapes through the air bleed flow path 9a indicated by the dotted arrow in the figures.

[0082] Furthermore, air 8 that has accumulated on the surface 53b side of support member 53 above base 41 moves along bottom surface 53e of recess 53c toward slit 53d, and is released upward through slit 53d and air release channel 9b indicated by the dotted arrow in the figure. In this way, air release mechanism 55 allows air 8 around impeller 40 to be released upward, preventing power consumption from increasing due to rotational friction caused by the presence of air accumulation.

[0083] FIG. 14 is a perspective view for explaining the submerged area and air storage area (air barrier area) of the sensor main body 10. As shown in FIG. 14(a) and 14(b) show partially cutaway top perspective views of the sensor main body 10, seen from different directions. As shown in FIGS. 14(a) and 14(b), the upper peripheral edge of the impeller support portion 51 in the measurement space 15 of the case member 11 is connected to the inner surface of the case member 11. A waterproof seal is applied between the upper peripheral edge of the impeller support portion 51 and the inner surface of the case member 11, for example, by means of caulking 7 made of silicone or the like. This prevents the measurement fluid from penetrating from the measurement space 15 side into the accommodation space 16 above it in the case member 11.

[0084] The air 8 released upward by the air extraction mechanism 55 gradually accumulates around the housing portion 52 and above the measurement space 15, forming an air layer between the measurement space 15 and the housing space 16. This air layer becomes the air barrier region. Any air 8 that cannot be stored in this air barrier region is discharged into the test water from the air outlet 6 provided below the upper end of the submerged range of the sensor main body 10.

[0085] In the sensor body 10, this air barrier region blocks the path of fluid infiltration into the accommodation space 16. That is, the impeller support part 51 in the measurement space 15 is waterproofed by the caulking 7 as described above, but the air layer in the air barrier region also prevents the caulking 7 from coming into direct contact with the measurement fluid during measurement.

[0086] After measurement, the submerged area of the case member 11 of the sensor body 10 is washed with running water from above, so that the measured fluid theoretically does not come into contact with the caulking 7, effectively preventing deterioration of the caulking 7 due to corrosion caused by the measured fluid.

[0087] Furthermore, in the sensor main body 10, these air barrier areas and caulking 7 provide a double waterproofing measure for the accommodation space 16 of the case member 11 when viewed from the measurement space 15 side. This prevents, for example, the measurement fluid from entering the accommodation space 16 from the measurement space 15 side during measurement, and the drive mechanism 60 and other components in the accommodation space 16 are completely isolated from the measurement space 15 side that comes into contact with the test water.

[0088] Furthermore, even if the caulking 7 is damaged, the drive motor 64 of the drive mechanism 60 is physically located in the storage space 16 above the submerged area of the sensor body 10 via an air barrier area, so the structure is able to minimize malfunctions due to water ingress.

[0089] [Modification of the first embodiment] Fig. 15 is a diagram illustrating a modified example of the impeller of the pump mechanism 50 in the sensor main body 10. Fig. 16 is a diagram illustrating the discharge of bubbles by the impeller. Fig. 15(a) shows a side view of the impeller, and Fig. 15(b) shows a plan view of the impeller.

[0090] 15(a) and 15(b), impeller 40A of a modified example of pump mechanism 50 differs from the previous impeller 40 in the structure of the plurality of blades 43. That is, each blade 43 of impeller 40A has an inclined surface 43a formed on the surface opposite to the surface in the rotation direction R of the impeller indicated by the arrow in the figure.

[0091] This inclined surface 43a forms, for example, a spherical curved surface that gradually widens and changes its inclination angle from tip 45 to base 41 of blade 43 of impeller 40A. This prevents the air bubbles from being trapped and unable to escape due to negative pressure when impeller 40A rotates with air bubbles adhering to blade 43 of impeller 40A. Note that inclined surface 43a is not limited to a curved surface and may be a flat surface.

[0092] That is, one of the causes of the entrainment of air bubbles is thought to be convection that occurs on the side opposite to the surface of blade 43 in the rotation direction R that scrapes out the fluid, and therefore convection is suppressed by providing inclined surface 43a. Also, since the entrainment of air bubbles can also occur due to low wettability based on the material, the surfaces of each blade 43 and conical portion 44 may be textured.

[0093] 16, air bubbles Ab generated around the impeller 40A are effectively discharged from the pump chamber 31 along the discharge path Ep passing through the discharge flow path 33 and the discharge port 34 by the rotation of the impeller 40A. Therefore, by using the impeller 40A together with the air extraction mechanism 55 described above, it is possible to more effectively release the air 8 and air bubbles Ab to the upper side of the measurement space 15. Note that although the above-described impellers 40 and 40A are exemplified as having three blades 43 formed at intervals of approximately 120° in the circumferential direction around the rotation axis, the plurality of blades 43 can also be configured with two blades 43 formed at intervals of approximately 180° in the circumferential direction around the rotation axis in order to reduce the number of locations where negative pressure is generated and make it easier for air bubbles to escape.

[0094] [Effects of the first embodiment] In the first embodiment, when the normal to the electrode surfaces of the working electrodes 75a and 75b of the sensor head 70 is parallel to the rotational axis direction of the impeller 40, if the discharge flow path 33 of the pump mechanism 50 is provided in the tangential direction on the discharge side of the rotational orbit of the impeller 40, it is necessary to either make the discharge flow path 33 horizontal and position the electrode surfaces of the working electrodes 75a and 75b at the same height as the discharge port, or to bend the discharge flow path 33 at a right angle toward the electrode surfaces of the working electrodes 75a and 75b. In the former case, the measurement fluid is reflected by the side surface of the sensor head 70, while in the latter case, reflection occurs at the bent part and the electrode surfaces of the working electrodes 75a and 75b. In either case, turbulence occurs in the flow of the measurement fluid.

[0095] In this regard, according to the first embodiment, the discharge flow path 33 from the pump chamber 31 to the electrode surfaces of the working electrodes 75a, 75b extends in a straight line obliquely upward from the intersection of the rotational orbit of the impeller 40 and the discharge-side tangent line toward the electrode surfaces of the working electrodes 75a, 75b, so that reflection of the measurement fluid, which is detrimental to measurement, does not occur within the discharge flow path 33 or on the surface of the sensor head 70. Furthermore, since the measurement fluid that reaches the sensor head 70 is discharged to the outside through the opening 13, reflection by the case member 11 does not occur either. This allows the flow of the measurement fluid to be smooth, thereby improving measurement accuracy.

[0096] Furthermore, the shape and structure of the impeller 40 and the structure of the air extraction mechanism 55 allow entrainment and accumulation of air and bubbles around the impeller 40 to be effectively released upward. This prevents an increase in power consumption of the drive mechanism 60, which is magnetically coupled to the impeller 40.

[0097] In addition, a drive mechanism 60 including a drive motor 64 is housed in a waterproof storage space 16 above the submerged range in the measurement space 15 of the sensor body 10, and an air barrier area is formed between the measurement space 15 and the storage space 16, which, together with the caulking 7, prevents the measurement fluid from entering the storage space 16.

[0098] Furthermore, since the sensor main body 10 is not constantly immersed in the test water, the electrode surface can be kept clean by removing the sensor head 70 after measurement and cleaning the electrode surface. This eliminates the need for beads or other cleaning tools to clean the electrode surface, making maintenance such as cleaning easier. Furthermore, since beads or other tools are not required, the measurement space 15 can have an open structure. Furthermore, since the pump head 30 can be attached and detached to the sensor main body 10 without using fastening parts, and the impeller 40 and other components can be replaced, foreign matter that has entered the measurement space 15 can be easily removed.

[0099] In the first embodiment, during the initial cleaning prior to normal measurement, the current value flowing between the counter electrode 73 and the working electrodes 75a, 75b is detected, and the empty water state is detected based on whether a predetermined current flows. This makes it possible to detect the empty water state (a state where the electrode is not submerged in water) during the initial cleaning, and to stop or prevent pump operation in the empty water state at an early timing before the start of measurement operation.

[0100] The residual chlorine meter 100 is also highly convenient because it can be easily used with one hand regardless of the measurement environment.The sensor main body 10 and the controller 20 can be easily connected and disconnected with one hand during measurement and when storing the device for transportation, making it highly portable.

[0101] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0102] 5 Second storage mounting section 10 Sensor body 11 Case material 12,13 Opening 14 Wall 15 Measurement space 16 Containment Space 18 Second measurement mounting part 20 Controller 21 First storage mounting part 22 First measurement mounting part 30 pump head 31 Pump Room 32 Intake port 33 Discharge flow path 34 Discharge port 40,40A impeller 43 Blade 44 Cone-shaped part 50 Pump mechanism 51 Impeller support 52 Storage section 53 Support member 54 Arm member 55 Air extraction mechanism 60 Drive mechanism 61 Follower magnet 62 Drive magnet 70 Sensor head 73 Counter electrode 74 Reference electrode (reference electrode) 75a,75b Working electrode 80 Measurement circuit 100 Residual Chlorine Meter

Claims

1. A sensor body having a lower end that can be immersed in the measurement fluid during measurement. Equipped with The sensor body includes: a measurement space provided at the lower end portion and connected to the outside via an opening; a pump mechanism including a suction port provided at the lower end portion, a pump chamber into which the measurement fluid is introduced via the suction port, an impeller provided in the pump chamber and driven to rotate, a discharge port facing the measurement space and discharging the measurement fluid introduced into the pump chamber into the measurement space, and a discharge flow path connecting the pump chamber and the discharge port; a drive mechanism that rotationally drives the impeller; a sensor head including an electrode facing the discharge port in the measurement space, the electrode coming into contact with the measurement fluid and outputting an oxidation / reduction current based on the concentration of free residual chlorine contained in the measurement fluid; and During the measurement, the discharge flow path of the pump mechanism extends obliquely upward in a straight line from the pump chamber toward the electrode. Residual chlorine meter.

2. During the measurement, the discharge flow path of the pump mechanism extends obliquely upward in a straight line from an intersection with a tangent line on the discharge side of the rotational orbit of the impeller toward the electrode surface of the electrode. The residual chlorine meter according to claim 1.

3. The sensor body includes: a case member formed in a cylindrical shape extending in the vertical direction and having the opening, The pump mechanism includes: a pump head that is detachably attached to a lower end side of the case member and that has the suction port, the pump chamber, the discharge flow path, and the discharge port formed therein; The drive mechanism includes: The impeller includes a driven member housed in the case member and provided at a base of the impeller, a drive member disposed opposite the driven member in the direction of the rotation axis of the impeller and magnetically coupled to the driven member to drive the impeller to rotate, and a drive motor for rotating the drive member. The residual chlorine meter according to claim 1.

4. The sensor head includes: A first columnar portion; a second columnar portion provided at one end of the first columnar portion and having a smaller diameter than the first columnar portion; a counter electrode and a reference electrode arranged parallel to a side surface of the first columnar portion; a plurality of working electrodes disposed at the tips of the second pillars; and The discharge flow path of the pump mechanism extends from the pump chamber toward the plurality of working electrodes. The residual chlorine meter according to claim 1.

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