JP2009085851A - Water quality sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water quality sensor where the length of an electrode for measuring the conductivity of fluid is shortened so that it can be utilized for a narrow pipe, for example. <P>SOLUTION: In the water quality sensor, four or more electrodes are radially held by an electrode holding section to measure the conductivity of fluid. By increasing the number of electrodes of measurement, the length of the electrode can be shortened while the superficial area of the electrodes is kept. In other words, even when cell constant is the same, the water quality sensor formed of the electrode is shorter than a water quality sensor formed of two electrodes. Therefore, in the water quality sensor, interference of the electrode during piping reduces, and the degree of freedom significantly increases in mounting it to a piping section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water quality sensor for measuring water quality.

  Conventionally, conductivity sensors have been used in equipment for water quality inspection, such as a total organic carbon meter. As this conductivity sensor, there is one that includes two rod-shaped electrodes in the middle of a pipe through which a fluid flows, and measures the electrical conductivity of the fluid by measuring a potential difference between the two electrodes. Such a conductivity sensor is provided by screwing into a piping portion using a piping member such as a tee. Moreover, as a device for measuring the conductivity of water, a sensor in which four rod-shaped electrodes are arranged in a row has been developed (see, for example, Patent Documents 1 and 2).

Japanese Utility Model Publication No. 62-203446 JP 2001-255294 A

  In the case of a conductivity sensor using two rod-shaped electrodes, when screwing into a pipe part, for example, when the length of the protruding part of the electrode is long, the pipe interferes with the electrode. The sensor shape is greatly limited. In addition, if the length of the electrode is shortened in accordance with the piping portion, the cell constant of the conductivity sensor may not be compatible with the fluid.

  The conductivity sensors of Patent Document 1 and Patent Document 2 use four rod-shaped electrodes, but the measurement electrodes used for measuring the conductivity of the fluid are the inner side of the electrodes arranged in one row. It is two. That is, it is substantially the same as a conductivity sensor composed of two electrodes and has the same problems.

  In view of the above situation, an object of the present invention is to provide a water quality sensor in which the length of an electrode for measuring the conductivity of a fluid is shortened so that it can be used, for example, even in a thin pipe.

  Therefore, the water quality sensor of the present invention has four or more rod-shaped electrodes for measuring the water quality and an electrode holding portion for holding the electrodes, and the electrodes are held radially at the end surfaces of the electrode holding portions. And at least one is a positive electrode and at least one is a negative electrode.

  According to the water quality sensor of the present invention, in order to measure the electrical conductivity of the fluid, four or more electrodes are held by the electrode holder so as to be arranged radially. By increasing the number of electrodes for measurement, the length of the electrode can be shortened while maintaining the surface area of the electrode. That is, even if the cell constant is the same, the water quality sensor is shorter than the water quality sensor composed of two electrodes. Therefore, in the water quality sensor of the present invention, the electrodes are less likely to interfere with the piping, and the degree of freedom when attached to the piping portion is greatly improved.

  Hereinafter, the present invention will be described with respect to a water quality sensor having 4, 6, 8, and 12 electrodes. The water quality sensor of the present invention will be described by taking conductivity as the physical quantity to be measured as water quality, but the present invention is not limited to this, and it is also possible to measure other physical quantities related to water quality such as specific resistance. is there. Moreover, although the water quality sensor comprised by the even number of 4, 6, 8, and 12 is illustrated as the number of electrodes, this invention may be an odd number.

[Embodiment 1]
As shown in FIGS. 1 and 2, the water quality sensor of the present invention described in Embodiment 1 includes four electrodes 10, 11, 12, and 13 and an electrode holder that holds the electrodes 10, 11, 12, and 13. Part 30.

  The electrodes 10, 11, 12, and 13 are rod-shaped electrodes made of, for example, stainless steel, silver, copper, brass, gold, platinum, titanium, and the like, and one end thereof has an electrode holding unit 30 so that a predetermined length protrudes. The other ends of the electrodes 10, 11, 12, and 13 are electrically connected to terminals 50, 51, 52, and 53 that are detachably connected to a positive electrode or a negative electrode of a power source (not shown) via a wiring (not shown). Each is connected.

  The electrode holding part 30 is a truncated cone-shaped member having a hollow inside and having an outer diameter that decreases from the connection side of the connection body 33 toward the one end face 31. Four holes 40, 41, 42, 43 are formed in the one end face 31 of the electrode holding part 30 in a radial pattern so as to match the outer shape of the electrodes 10, 11, 12, 13. The electrodes 10, 11, 12, 13 are held by the electrode holding part 30 so that one ends of the 12, 13 protrude. More specifically, the four holes 40, 41, 42, 43 are formed on a circle having a predetermined radius around a center point 36 as an arbitrary point on the one end face 31. That is, the electrodes 10, 11, 12, and 13 are arranged radially about the center point 36 of the one end surface 31 of the electrode holding unit 30. More specifically, the electrodes 10, 11, 12, and 13 are arranged on a circle having a predetermined radius with the center point 36 as the center.

  The holes 40, 41, 42, 43 are provided at positions where the electrodes 10, 11, 12, 13 are arranged at equal intervals. The holes 40, 41, 42, and 43 are provided with the electrodes 10, 11, 12, and 13, so that the holes 40, 41, 42, and 43 are sealed without gaps, so that the fluid does not flow into the inside when measuring the conductivity of the fluid.

  On the other end face side of the electrode holding portion 30, a cable 35 for bundling wires electrically connected to the other ends of the electrodes 10, 11, 12, and 13 is inserted so as to protrude through a connection body 33 described later. A cable projecting portion 32 is provided, and the cable projecting portion 32 and the electrode holding portion 30 are connected by a connection body 33 having a hollow interior such as a hexagon bolt. That is, the inside of the electrode holding portion 30 and the cable protruding portion 32 connected via the connection body 33 is connected, and the other end of the electrodes 10, 11, 12, 13 is approximately inside the connection body 33, The wiring is connected.

  When the water quality sensor having such a structure is provided in the pipe 60 as shown in FIG. 3, a hole 61 is formed from the outside of the pipe according to the outer diameter in the vicinity of the center of the outer side surface of the electrode holding unit 30. The electrode holding unit 30 is inserted into the electrode 61 so that the electrodes 10, 11, 12, 13 are brought into contact with the fluid in the pipe. And each of the terminals 50, 51, 52, 53 connected to the wiring bundled in the cable 35 protruding from the cable protrusion 32 is detachably connected to the positive electrode or the negative electrode of the power source.

  At this time, as a method of connecting the terminals 50, 51, 52, and 53, that is, the electrodes 10, 11, 12, and 13, to the power source, at least one electrode is connected to each of the positive electrode and the negative electrode of the power source. It is not limited. Then, by measuring the potential difference between the electrodes 10, 11, 12, 13, the conductivity of the fluid flowing between the electrodes 10, 11, 12, 13 can be measured.

  When measuring the conductivity of a fluid, it is necessary to use a water quality sensor having a cell constant compatible with the fluid. The cell constant of this water quality sensor depends on the distance between the electrodes and the surface area of the electrode in contact with the liquid, that is, the length and thickness of the electrode in contact with the liquid. In the case of the water quality sensor described in the first embodiment, since there are more electrodes for measuring the conductivity than in the past, if electrodes of the same thickness are used, the electrodes 10, 11, By connecting 12 and 13 to be equal, the surface area is increased. Therefore, the length of the electrode can be shortened as compared with a conventional water quality sensor composed of two electrodes having the same cell constant value.

  As an example, a water quality sensor of the present invention is compared with a water quality sensor of the same type using two electrodes as shown in FIG. 4 as a conventional water quality sensor using an electrode having a diameter of 3 mm. In this case, the water quality sensor of the present invention and the conventional water quality sensor are separated by a certain distance from the center point 36 of the one end face 31 of the electrode holding portion 30 where the electrodes are held, and the distances between the electrodes are equal. Is provided. In the case of a conventional water quality sensor having two electrodes, if the cell constant value is 0.2, the length of the electrode is 14 mm.

  On the other hand, in the case of the water quality sensor of the present invention, when the electrodes facing each other through the center point 36 as an arbitrary point are connected to the power source so as to have the same polarity, the electrode length is 4.5 mm and the cell constant value is 0.2, and the length of the electrode can be shortened by 68%. That is, when an electrode is provided in a pipe 60 having a small inner diameter, for example, an inner diameter of 9 mm as shown in FIG. 3, a conventional water quality sensor composed of two electrodes cannot be provided. It becomes possible to provide a water quality sensor. Therefore, it is possible to reduce the size of the entire piping, and it is possible to reduce the conductivity measuring device including the water quality sensor.

  Next, the connection of the electrode of the water quality sensor described in the first embodiment to the power source will be described. The electrodes 10, 11, 12, 13 have the same shape and are provided at equal intervals on a circle with a predetermined radius centered on a central point as an arbitrary point on one end face 31 of the electrode holding unit 30. The electrode surface area, the distance between adjacent electrodes, and the distance between electrodes facing each other through the center thereof are the same. From the viewpoint of the cell constant, there are three combinations of connections of the four electrodes of the water quality sensor described in the first embodiment to the power source as shown in FIGS.

  The electrode connection (parallel connection) shown in FIG. 5 is a combination of connecting to the positive electrode and the negative electrode of the power source such that the opposing electrodes have different polarities via the center point 36. The electrode connection (cross connection) shown in FIG. 6 is a combination of connecting to the positive electrode and the negative electrode of the power supply with the opposite electrodes having the same polarity via the center point 36. The electrode connection (3: 1 connection) shown in FIG. 7 is the positive electrode of the power supply in which one of the four electrodes is the positive electrode or negative electrode of the power supply, and the remaining three electrodes are different from the other electrodes. And a combination connected to the negative electrode. In FIGS. 5 to 7, the electrodes shown in black or white indicate that the same colors are connected to the same pole. Hereinafter, it shows similarly in the same figure.

  FIG. 8 is a graph showing the relationship between the cell constant and conductivity in water quality sensors having different combinations of electrode lengths and connections. As shown in FIG. 8, it can be seen that even if the length of the electrode is the same, the cell constant changes depending on the combination of electrode connections. This result shows the same tendency even when the length of the electrode is changed, and it can be seen that it functions as a water quality sensor having different cell constants by changing the combination of the connections of the four electrodes.

  In the water quality sensor, when the electrical conductivity is accurately measured, it is necessary to use a water quality sensor having a cell constant compatible with the fluid. Conventionally, it was necessary to prepare several types of water quality sensors with different cell constants, but the water quality sensor of the present invention can change the cell constant without changing the shape of the water quality sensor by changing the combination of connections. it can. That is, it is possible to cope with one water quality sensor, and it is possible to measure the conductivity more precisely. In this case, it is preferable that the cell constant of the water quality sensor is obtained in advance using a standard solution, and the combination of electrode connections to the power source is appropriately changed according to the state of the actually measured fluid.

[Embodiment 2]
In the first embodiment, the water quality sensor composed of four electrodes for measuring conductivity has been described. However, the water quality sensor of the present invention is not limited to this as long as it has four or more electrodes. Absent. In the second embodiment, a water quality sensor having six electrodes for measuring conductivity will be described. The water quality sensor described in the second embodiment is the same as the first embodiment except that the number of electrodes and the arrangement of the electrodes are different.

  The six electrodes of the water quality sensor are held so as to be radially arranged on one end face 31 of the electrode holding unit 30 as shown in FIG. More specifically, the electrodes are arranged radially about a center point 36 as an arbitrary point on the one end face 31. Furthermore, electrodes are arranged at equal intervals on a circle having a predetermined radius with the center point 36 as the center.

  The electrodes are connected to the positive and negative electrodes of the power supply so that the electrodes facing each other through the center point 36 have different polarities, and three of the six electrodes are positive and the remaining three. Are connected so as to be a negative electrode. That is, the adjacent electrodes are connected so as to have different polarities. Even with such a water quality sensor having six electrodes, the conductivity of the fluid can be measured as in the first embodiment.

  FIG. 10 is a graph showing the relationship between the cell constant and conductivity in water quality sensors having different electrode lengths in contact with liquid. Here, the distance between the electrodes facing each other via the center point 36 and the water quality sensor holding the six electrodes on the electrode holding unit 30 with the distance between the electrodes facing each other via the center point 36 being 12.5 mm. Was measured using a water quality sensor in which 6 electrodes were held in the electrode holding unit 30 with a thickness of 15.5 mm.

  As shown in FIG. 10, it can be seen that the cell constant changes by changing the distance between the electrodes. Such a water quality sensor having six electrodes can also change the cell constant by changing the combination of connection of the electrodes to the power source. Moreover, since the surface area of an electrode can be enlarged by increasing the number of electrodes, the length of an electrode can be shortened. In the second embodiment, the number of electrodes connected to the positive electrode is the same as the number of electrodes connected to the negative electrode. However, as in the 3: 1 connection of the first embodiment, X: Y (X and Y are They may be connected so that the ratio is a natural number and satisfies X + Y = 6.

[Embodiment 3]
In the third embodiment, a water quality sensor having eight electrodes for measuring conductivity will be described. The water quality sensor described in the third embodiment is the same as in the first and second embodiments except that the number of electrodes and the arrangement of the electrodes are different.

  The eight electrodes of the water quality sensor are held so as to be radially arranged on one end face 31 of the electrode holding unit 30 as shown in FIGS. More specifically, the electrodes are arranged radially about a center point 36 as an arbitrary point on the one end face 31. Further, with the center point 36 as the center, four electrodes, which are part of the electrodes, are arranged at equal intervals on a circle with a predetermined radius, and further on a circle with a radius larger than the predetermined radius. The remaining four electrodes are arranged at equal intervals. The electrodes are connected to the positive electrode and the negative electrode of the power supply so that the electrodes facing each other through the center point 36 have the same polarity.

  Furthermore, in the case of the connection combination shown in FIG. 11, all four electrodes arranged on the inner circle have the same polarity, and the remaining four electrodes arranged on the outer circle are the inner four. The electrodes are connected so as to have different polarities. In the case of the connection combination shown in FIG. 12, the four electrodes arranged on the inner and outer circles are connected so that every other electrode has a different polarity. Even with such a water quality sensor having eight electrodes, the conductivity of the fluid can be measured as in the first embodiment.

  FIG. 13 is a graph showing the relationship between the cell constant and conductivity in a water quality sensor having electrodes connected to the positive electrode and the negative electrode of the power source by the combination of connections shown in FIG. Here, the distance between the electrodes facing each other via the center point 36 of the four electrodes arranged on the inner side is set to 7.5 mm or 8.5 mm, and the center point 36 of the four electrodes arranged on the outer side is set. Measured using four types of water quality sensors in which the distance between the electrodes facing each other is 12.5 mm, 14.5 mm, or 16 mm and the eight electrodes are held in the electrode holder 30.

  As shown in FIG. 13, when the distance between the inner electrodes is changed from 7.5 mm to 8.5 mm, the distance between the inner and outer electrodes is shortened. Therefore, the cell constant becomes small. Further, when the distance between the outer electrodes is changed from 12.5 mm to 14.5 mm and 16 mm, the distance between the inner and outer electrodes becomes longer and the cell constant becomes larger.

  FIG. 14 is a graph showing the relationship between the cell constant and the conductivity in a water quality sensor having electrodes connected by the combination of connections shown in FIG. In addition, here, it measured using four types of water quality sensors used when measuring electrical conductivity by the combination of connections shown in FIG. Even in the combination of connections shown in FIG. 12, the cell constant varies depending on the distance between the electrodes, as in FIG.

  As shown in FIGS. 13 and 14, the cell constant can be changed without changing the shape of the water quality sensor by changing the combination of the connection of the electrode to the positive electrode and the negative electrode of the power source. Moreover, since the surface area of an electrode can be enlarged by increasing the number of electrodes, the length of an electrode can be shortened. In the third embodiment, the number of electrodes connected to the positive electrode and the number of electrodes connected to the negative electrode are described as the same number. However, like the 3: 1 connection in the first embodiment, X: Y (X and Y are They may be connected so that the ratio is a natural number and satisfies X + Y = 8.

[Embodiment 4]
In the fourth embodiment, a water quality sensor having 12 electrodes for measuring conductivity will be described. The water quality sensor described in the fourth embodiment is the same as in the first to third embodiments except that the number of electrodes and the arrangement of the electrodes are different.

  The twelve electrodes of the water quality sensor are held so as to be radially arranged on one end face 31 of the electrode holding portion 30 as shown in FIGS. More specifically, the electrodes are arranged radially about a center point 36 as an arbitrary point on the one end face 31. Further, with the center point 36 as the center, four electrodes, which are part of the electrodes, are arranged at equal intervals on a circle with a predetermined radius, and further on a circle with a radius larger than the predetermined radius. The remaining eight electrodes are arranged at equal intervals. The electrodes are connected to the positive electrode and the negative electrode of the power supply so that the electrodes facing each other through the center point 36 have the same polarity.

  Further, in the case of the connection combination (A) shown in FIG. 15, all four electrodes arranged on the inner circle have the same polarity, and the remaining eight electrodes arranged on the outer circle It is connected so as to have a different polarity with respect to the four inner electrodes. In the case of the connection combination (B) shown in FIG. 16, the four electrodes arranged on the inner circle are connected so that every other electrode has a different polarity, and 8 arranged on the outer circle. Every two electrodes are connected so as to have different polarities. In the case of the connection combination (C) shown in FIG. 17, the four electrodes arranged on the inner circle are connected so that every other electrode has a different polarity, and 8 arranged on the outer circle. Every other electrode is connected so as to have a different polarity.

  FIG. 18 is a graph showing the relationship between the cell constant and conductivity in a water quality sensor having electrodes connected to the positive electrode and the negative electrode of the power source by the combination of connections as shown in FIGS. 15 to 17. Here, the distance between the electrodes facing each other via the center point 36 of the four electrodes arranged on the inner side is 7.5 mm, and the distance between the center points 36 of the eight electrodes arranged on the outer side is opposed. It was measured using a water quality sensor with a distance between electrodes of 16 mm.

  As shown in FIG. 18, the cell constant can be changed without changing the shape of the water quality sensor by changing the combination of the connection of the electrode to the positive electrode and the negative electrode of the power source. Moreover, since the surface area of an electrode can be enlarged by increasing the number of electrodes, the length of an electrode can be shortened. In the fourth embodiment, the number of electrodes connected to the positive electrode and the number of electrodes connected to the negative electrode have been described as the same number. However, like the 3: 1 connection in the first embodiment, X: Y (X and Y are They may be connected so as to have a ratio of a natural number satisfying X + Y = 12.

  As described in the first to fourth embodiments, the number of electrodes for measurement can be reduced by using four or more electrodes. However, the number of electrodes may be four or more. The odd number or even number may be sufficient.

  As described above, in the water quality sensor of the present invention, the electrode serving as the positive electrode and the electrode serving as the negative electrode can be appropriately changed by changing the connection wiring with the power source. Changing the connection wiring, that is, changing the combination of the positive electrode and the negative electrode changes the surface area and the distance between the electrodes. In other words, the cell constant can be changed without changing the appearance of the water quality sensor. At this time, it is not necessary to make all the electrodes positive or negative, and there may be electrodes that are not connected to the power source.

  Furthermore, a water quality sensor having various functions can be obtained by changing the wiring circuit of the electrodes. For example, in the above description, the electrode is used to measure the potential difference of the fluid. However, the present invention is not limited to this, and the current value can be measured by changing the wiring circuit of the electrode. It is also possible to coexist a measurement electrode and a current value measurement electrode. Furthermore, physical quantities as water quality such as conductivity and specific resistance that can be measured by a water quality sensor may change depending on fluid contamination or temperature. In this case, the water quality sensor of the present invention can also be used as a compensation electrode for compensating for a physical quantity that varies depending on fluid contamination or temperature by changing a part of the wiring circuit of the electrode. That is, by changing the electrode wiring in this way, not only the cell constant but also the water quality sensor can have various functions.

  In the above description, the measurement of conductivity has been described as an example. However, the water quality sensor of the present invention can also measure the specific resistance which is the reciprocal of conductivity, and the current, voltage, resistance, etc. of the fluid flowing between the electrodes. Can be measured as water quality.

[Embodiment 5]
The water quality sensor described in Embodiments 1 to 4 described above may include an electrical component that includes an amplifier as an amplifier connected to a plurality of electrodes inside the electrode holding unit. In the fifth embodiment, a water quality sensor including an electrical unit including this amplifier will be described. In the fifth embodiment, the electrode holding portion of the water quality sensor having the four electrodes described in the first embodiment is provided with an electrical component, but the present invention is not limited to this. Absent.

  As shown in FIGS. 19 and 20, the water quality sensor described in the fifth embodiment includes four electrodes 10, 11, 12, and 13 and an electrode holding unit 30 that holds the electrodes 10, 11, 12, and 13. have. Since the electrodes 10, 11, 12, 13 and the electrode holding unit 30 are the same as those in the first embodiment, the description thereof is omitted.

  On the other end face side of the electrode holding part 30, an electrical equipment part 39 is provided via a connection body 33 formed integrally with the electrode holding part 30. For example, by forming the connection body 33 into a shape like a hexagon bolt, a water quality sensor described in the fifth embodiment can be easily provided in the flow path using a spanner or the like. The electrical component 39 is formed of a housing and a lid that are hollow inside and integrally formed with the connection body 33, and includes a lid that can be opened and closed on the opposite side of the housing from the side where the connection body 33 is provided. It has a structured. In addition, an amplification circuit board 37 including an amplifier as an amplifier that amplifies signals detected by the electrodes 10, 11, 12, and 13 is housed in the electrical unit 39, and a cable extending from the amplification circuit board 37. 38 protrudes from the side surface of the housing of the electrical component 39. In addition, although the housings of the electrode holding unit 30, the connection body 33, and the electrical unit 39 are integrally formed, they may be formed by assembling ones configured as independent members.

  Each electrode 10, 11, 12, 13 is connected to the input of the amplifier of the amplification circuit board 37 via wiring in the electrical component 39, and the signal detected by each electrode 10, 11, 12, 13 is Amplified and a current or voltage is measured based on the amplified signal. A physical quantity as water quality such as conductivity and specific resistance can be measured by the measured current or voltage.

  In this way, the electrical component 39 and the electrode holder 30 that holds the electrodes 10, 11, 12, and 13 are integrated, so that the electrodes 10, 11, 12, and 13 are connected to the amplifier circuit board 37. Since the wiring is housed in the electrical unit 39 integrated with the electrode holding unit 30, the number of wirings to be provided outside the water quality sensor is reduced, and the connection reliability between the wiring and the amplifier circuit board 37 is improved. Can be made.

[Embodiment 6]
In the sixth embodiment, as shown in FIG. 21, instead of the electrode holding unit 30 of the water quality sensor shown in the above-described first to fifth embodiments, an electrode holding unit 70 including an internal flow channel 71 is used. It is. About members other than this electrode holding part 70, since it is the same as that of Embodiment 5, description is abbreviate | omitted.

  The electrode holding part 70 is a hollow member that is formed of an insulating material and has an internal channel 71 bent in an L shape through which a fluid flows, and also functions as a channel through which the fluid flows. Here, as the insulating material, a resin material having corrosion resistance is suitable, and examples thereof include polyvinylidene fluoride (PVDF).

  The electrode holding unit 70 includes electrodes 10, 11, 11 similar to those in the first embodiment at the bent portion of the internal flow channel 71, which is substantially the center of the internal flow channel 71 in the direction in which the fluid flows (in the direction of arrow 79 in FIG. 21). Four holes 45, 46, 47, 48 that match the outer diameter of 12, 13 are formed. The holes 45, 46, 47, 48 are through holes that connect the outside of the electrode holding part 70 and the internal flow path 71, and the electrodes 10, 11, 12, 48 are connected to the holes 45, 46, 47, 48. One end of 13 is inserted so as to be disposed in the internal flow path 71 and held by the electrode holding portion 70. At this time, the holes 45, 46, 47, 48 are structured such that the fluid flowing through the internal flow path 71 does not leak by holding the electrodes 10, 11, 12, 13.

  The electrode holding portion 70 is integrally formed with a fluid inflow portion 72 through which fluid flows into one end portion and a fluid outflow portion 73 through which fluid flows out at the other end portion. The fluid inflow portion 72 is a connection member connected to the flow path 80 through which the fluid flows. The fluid inflow portion 72 has an outer diameter smaller than the inner diameter of the opening 81 of the flow path 80 and is shaped to be fitted inside the opening 81. That is, the flow path inflow portion 72 is a male connection member. In addition, a protrusion 75 having substantially the same shape as the protrusion 82 of the opening 81 is provided on the downstream side in the flow direction of the fluid in the flow path inflow part 72 so as to make a round around the outer periphery of the fluid inflow part 72. And the hollow 76 is formed in the part fitted inside the opening part 81 in the fluid inflow part 72 so that the outer periphery of the fluid inflow part 72 may go around, and it is for preventing the fluid from leaking into this hollow 76. An O-ring 83 is provided. Then, the projection 75 of the flow channel inflow portion 72 is fitted into a so-called quick fastener 85 in which a plate-like member is formed in a substantially C ring shape together with the projection 82 of the opening 81, whereby the electrode holding portion 70, the flow channel 80, Is connected. With this quick fastener 85, the water quality sensor of the present invention can be easily handled like a connector.

  The flow channel outflow portion 73 is a connection member connected to the flow channel 80 in which a fluid flows in a shape substantially the same as the flow channel inflow portion 72. The fluid outflow portion 73 has an outer diameter smaller than the inner diameter of the opening portion of the flow path (not shown), and is shaped to be fitted inside the opening portion. That is, the channel outflow portion 73 is a male connection member. Further, a protrusion 77 is provided on the downstream side of the flow path outflow portion 73 in the direction in which the fluid flows so as to make a round around the outer periphery of the fluid outflow portion 73. A recess 78 is formed in the fluid outflow portion 73 so as to go around the outer periphery of the fluid outflow portion 73, and the recess 78 is provided with an O-ring (not shown) for preventing the fluid from leaking out. The projection 75 of the flow channel outflow portion 73 is fitted into the quick fastener 85 in the same manner as the projection 75 of the flow channel inflow portion 72.

  In the water quality sensor described in the sixth embodiment formed as described above, the fluid that has flowed into the fluid inflow portion 72 through the opening 81 of the flow channel 80 passes through the internal flow channel 71 of the electrode holding portion 70 and flows. It flows out from the road outflow part 73. At this time, the water quality sensor measures the water quality of the fluid flowing through the internal flow path 71 by the electrodes 10, 11, 12, and 13, as described above. Thus, the water quality sensor of the present invention described in Embodiment 6 has such a structure, so that the water quality sensor can be easily provided in the flow path. In the process of connecting the water quality sensor, the possibility that the worker touches the part where the fluid flows or the fluid flows without completing the adequate and appropriate connection is reduced. Can reduce the risk.

  Further, the water quality sensor described in the sixth embodiment is provided with an outer pole 90 so as to surround the periphery of 10, 11, 12, 13 disposed in the internal flow path 71 as shown in FIG. Also good.

  The outer electrode 90 is a cylindrical member made of substantially the same material as the electrodes 10, 11, 12, 13 such as stainless steel, silver, copper, brass, gold, platinum, titanium, etc., and has an internal flow path. 71 is provided at a position corresponding to the tip portion of the electrodes 10, 11, 12, 13 disposed in the internal flow path 71 on the side surface of 71. The outer pole 90 is connected to a wiring 91 extending from the amplification circuit board 37 in the electrical component 39 and has substantially the same function as the rod-shaped electrodes 10, 11, 12, and 13. That is, the water quality of the fluid can be measured by the five electrodes configured by the electrodes 10, 11, 12, 13 and the outer electrode 90. Therefore, the cell constant can be changed by changing the wiring connection, and a cell constant more suitable for the fluid can be selected. That is, the water quality of the fluid can be measured in more detail.

  In the sixth embodiment, the electrode holding part 70 is provided with the internal flow path 71, but the flow path forming body having the internal flow path 71, the fluid inflow part 72, and the fluid outflow part 73 is implemented. You may make it hold | maintain the electrode holding | maintenance part 30 of the water quality sensor demonstrated in the form 1 thru | or 5. In this case, a holding hole that matches the shape of the electrode holding part 30 is formed in the flow path forming body, and the electrode holding part 30 is configured so that one end of the electrode is disposed in the internal flow path 71. It is held in the holding hole. At this time, the electrode holding part 30 is held in the holding hole, so that the fluid flowing through the internal flow path 71 does not leak. Even if it is such a water quality sensor, while having the same effect as the above, if it has the same shape electrode holding part 30, it will become easy to replace.

  The water quality sensor of the present invention described in the sixth embodiment is not limited to the above description, and for example, the internal channel 71 includes a thermosensitive element such as a thermistor or a thermocouple for detecting the temperature of the fluid. It may be a thing.

1 is a side view of a water quality sensor described in Embodiment 1. FIG. 1 is a front view of a water quality sensor described in Embodiment 1. FIG. It is a figure which shows the water quality sensor demonstrated in Embodiment 1 with which piping was equipped. It is a side view of the conventional water quality sensor. It is a figure explaining the combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 1 to a power supply. It is a figure explaining another combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 1 to a power supply. It is a figure explaining another combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 1 to a power supply. It is a graph which shows the relationship between the electrical conductivity in the water quality sensor demonstrated in Embodiment 1, and a cell constant. It is a figure explaining the combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 2 to a power supply. It is a graph which shows the relationship between the electrical conductivity in the water quality sensor demonstrated in Embodiment 2, and a cell constant. It is a figure explaining the combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 3 to a power supply. It is a figure explaining another combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 3 to a power supply. It is a graph which shows the relationship between the electrical conductivity in a water quality sensor demonstrated in Embodiment 3 which has the combination of a connection shown by FIG. 11, and a cell constant. It is a graph which shows the relationship between the electrical conductivity in a water quality sensor demonstrated in Embodiment 3 which has the combination of a connection shown by FIG. 12, and a cell constant. It is a figure explaining the combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 4 to a power supply. It is a figure explaining another combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 4 to a power supply. It is a figure explaining another combination at the time of connecting the electrode of the water quality sensor demonstrated in Embodiment 4 to a power supply. It is a graph which shows the relationship between the electrical conductivity in the water quality sensor demonstrated in Embodiment 4, and a cell constant. FIG. 10 is a side view of a water quality sensor described in a fifth embodiment. FIG. 10 is a front view of a water quality sensor described in a fifth embodiment. It is a partially cutaway sectional view of a water quality sensor described in a sixth embodiment. It is sectional drawing of the water quality sensor demonstrated in Embodiment 6. FIG.

Explanation of symbols

10, 11, 12, 13 Electrode 30, 70 Electrode holding part 31 One end face 32 Cable protrusion 33 Connector 35, 38 Cable 36 Center point 37 Amplifying circuit board 39 Electrical parts 40, 41, 42, 43, 45, 46, 47, 48 Hole 50, 51, 52, 53 Terminal 60 Pipe 61 Hole 71 Internal flow path 72 Fluid inflow part 73 Fluid outflow part 75, 77, 82 Protrusion 76, 78 Depression 80 Channel 81 Opening 83 O-ring 90 Outer pole 91 Wiring

Claims (5)

Four or more rod-shaped electrodes for measuring the water quality of the fluid;
An electrode holding part for holding the electrode;
The electrode is held radially by the end face of the electrode holding portion, and at least one or more electrodes are configured as a positive electrode and at least one or more electrodes are configured as a negative electrode.   The water quality sensor according to claim 1, wherein the electrode changes a combination of an electrode configured as the positive electrode and an electrode configured as the negative electrode.   3. The water quality sensor according to claim 1, wherein an electrical component including an amplifier connected to a plurality of the electrodes is integrally formed in the electrode holding unit. The electrode holding part is
An internal flow path through which the fluid flows is formed, the fluid flows into one end, a fluid inflow section connected to the flow path through which the fluid flows, and the fluid flows out to the other end so that the fluid flows A fluid outflow part connected to a flow path is provided, and the electrode is held so that one end of the electrode is disposed in the internal flow path. Water quality sensor.   The water quality sensor according to claim 4, wherein the fluid inflow portion and / or the fluid outflow portion are connected to the flow path by a quick fastener.