Liquid analysis device and sensor unit

Abstract

The present invention reduces the operating cost of a liquid analysis device and reduces electromagnetic noise superimposed on an analog signal. The device comprises: a sensor unit (21) which contacts a liquid and outputs an analog signal corresponding to a predetermined measurement object item; a conversion unit (22) which converts the analog signal obtained by the sensor unit (21) into a digital signal; and a device body (3) which is connected to the conversion unit (22) by wire or wireless means and obtains a digital signal from the conversion unit (22). The sensor unit (21) and the conversion unit (22) are configured in a manner that allows them to be loaded and unloaded from each other. The sensor unit (21) has a connection plug (212) for electrically connecting to the conversion unit (22), and a metal shield (5) is provided at the connection portion of the connection plug (212) and the wiring of the sensor unit (21).

Description

Technical Field

[0001] The present invention relates to a liquid analyzing device for analyzing a liquid and a sensor unit for analyzing a liquid. Background Art

[0002] A device for measuring pH, dissolved oxygen, etc. in a liquid such as environmental water, industrial water, or water in sewage treatment, as shown in Patent Document 1, comprises: a sensor unit that is immersed in the liquid and outputs a detection signal corresponding to a predetermined measurement object item; and a device body that obtains the detection signal from the sensor unit and displays the measurement value.

[0003] Here, the sensor unit includes: a sensor unit that outputs an analog signal corresponding to a measurement target item; a converter that amplifies the analog signal from the sensor unit and converts it into a digital signal; and a housing that houses the sensor unit and the converter.

[0004] However, in the above-mentioned sensor unit, the part of the housing that houses the sensor unit and the part that houses the A / D converter unit are inseparable. Therefore, when the sensor unit is replaced due to deterioration of the sensor unit, the converter unit that does not need to be replaced must be replaced together, resulting in increased running costs.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-20246 Summary of the invention

[0008] Technical issues

[0009] Here, the inventors of the present application considered that a sensor unit that is immersed in liquid and outputs an analog signal corresponding to a predetermined measurement target item and a conversion unit that converts the analog signal obtained by the sensor unit into a digital signal are configured in a manner that they can be attached and detached from each other. At this time, it is considered that the sensor unit is configured with a connection plug for electrical connection with the conversion unit. In this case, electromagnetic noise may be introduced to the analog signal from the connection portion of the connection plug and the wiring of the sensor unit.

[0010] Therefore, the present invention has been made to solve the above-mentioned problems, and its main subject is to reduce the running cost of the liquid analysis device and reduce the electromagnetic noise superimposed on the analog signal.

[0011] Technical Solution

[0012] That is, the liquid analysis device of the present invention is characterized in that it comprises: a sensor part, which is immersed in liquid and outputs an analog signal corresponding to a predetermined measurement object item; a conversion part, which converts the analog signal obtained by the above-mentioned sensor part into a digital signal; and a device body, which is connected to the above-mentioned conversion part by wire or wireless means and obtains the digital signal from the above-mentioned conversion part, the above-mentioned sensor part and the above-mentioned conversion part are constructed in a manner that can be loaded and unloaded from each other, the above-mentioned sensor part has a connection plug for electrically connecting to the above-mentioned conversion part, and a metal shield is provided at the connection part between the above-mentioned connection plug and the wiring of the above-mentioned sensor part.

[0013] According to the liquid analysis device, since the sensor unit and the conversion unit are configured to be detachable from each other, when the sensor unit is replaced, only the sensor unit needs to be replaced without replacing the conversion unit, thereby reducing the running cost of the liquid analysis device. In addition, since a metal shield is provided at the connection portion between the connection plug and the wiring of the sensor unit, electromagnetic noise superimposed on the analog signal from the connection portion between the connection plug and the wiring of the sensor unit can be reduced, thereby improving the measurement accuracy.

[0014] In the case where the sensor unit and the converter unit are integrated in a state of being electrically connected by the connection plug and operated by hand, electromagnetic noise is easily superimposed due to static electricity from the hand. In this case, the effect of the present invention becomes more significant.

[0015] As the sensor unit, a pH sensor, a dissolved oxygen sensor, a conductivity sensor, an oxidation-reduction potential sensor, an ion concentration sensor of calcium, potassium, etc., a turbidity sensor, etc., which can detect a value indicating a liquid property, can be considered. Among these, the pH sensor is particularly susceptible to the influence of electromagnetic noise, and the SN ratio deteriorates. Therefore, it is preferable to provide the above-mentioned metal shield in the sensor unit that measures pH as a measurement object item.

[0016] During measurement or calibration, confirm whether the output of the sensor unit is stable. Here, even if the display unit of the device body shows that the output of the sensor unit is stable, the user's awareness is mostly on the sensor unit composed of the sensor unit and the conversion unit, and it cannot be said that the user's convenience is good. Therefore, in order to improve the convenience of use of the liquid analysis device, it is preferred that the conversion unit has a notification unit that notifies that the output of the sensor unit is stable during measurement and calibration.

[0017] The device body can obtain measurement results of multiple measurement locations or multiple measurement target items by connecting multiple conversion parts each equipped with a sensor part. At this time, in order to easily operate multiple sensor units composed of sensor parts and conversion parts, it is preferred to have a connection mechanism that connects the multiple conversion parts to each other. Thus, the user can simply hold multiple sensor units with one hand.

[0018] The connection mechanism preferably connects the plurality of conversion parts in such a manner that at least one of the positions from the bottom of the water to the sensing portion (e.g., the response glass in the case of the glass electrode) or the positions from the surface of the water to the sensing portion of the sensor parts respectively mounted on the plurality of conversion parts is the same position. With this configuration, it is easy to set the plurality of sensor parts at, for example, the same depth position.

[0019] For the above-mentioned device main body, if a plurality of the above-mentioned conversion parts on which a plurality of the above-mentioned sensor parts with different measurement object items are respectively installed are connected, a plurality of measurement object items can be measured at one time. In this structure, it is preferred that the above-mentioned device main body has a calibration part that calibrates the above-mentioned plurality of sensor parts with different measurement object items at the same time. Here, simultaneous calibration means that the timing of starting the calibration of a plurality of sensors is the same, and each calibration process after the start is performed in parallel. If it is this structure, since the calibration of each sensor part can be performed at one time, the calibration time can be shortened. At this time, the above-mentioned device main body takes into account the use of calibration substances of different types to calibrate the above-mentioned plurality of sensor parts with different measurement object items.

[0020] The device body preferably includes: a connection port to which a cable extending from the conversion unit is connected; and a sensor identification unit to identify a sensor unit installed in the conversion unit connected to the connection port. With this configuration, regardless of the type of sensor unit installed in the conversion unit, all can be connected to the common connection port.

[0021] Considering that liquid analysis is performed not only when the device body is held in the hand, but also when the device body is placed, it is considered that a support component is provided on the device body to support the device body in an inclined or upright state. In this configuration, the support component is preferably configured to be able to wind up a cable connecting the conversion unit and the device body. With this configuration, the cable can be bundled, and the cable is not likely to become an obstacle when the liquid analysis device is carried or stored.

[0022] The sensor unit of the present invention is characterized in that it comprises: a sensor part, which contacts a liquid and outputs an analog signal corresponding to a predetermined measurement object item; and a conversion part, which converts the analog signal obtained by the above-mentioned sensor part into a digital signal and transmits it to the outside, the above-mentioned sensor part and the above-mentioned conversion part are constructed in a manner that can be loaded and unloaded from each other, the above-mentioned sensor part has a connecting plug for electrically connecting to the above-mentioned conversion part, and a metal shield is provided at the connecting part between the above-mentioned connecting plug and the wiring of the above-mentioned sensor part.

[0023] Effects of the Invention

[0024] According to the present invention described above, since the sensor unit and the converter unit are detachably configured, when the sensor unit is replaced, only the sensor unit need not be replaced, thereby reducing the running cost of the liquid analysis device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an overall schematic diagram of a liquid analysis device according to one embodiment of the present invention.

[0026] Figure 2 This is a functional block diagram of the device body of this embodiment.

[0027] Figure 3 It is a front view of a state where the sensor unit of this embodiment is attached and a state where the sensor unit is detached.

[0028] Figure 4 This is a partially enlarged cross-sectional view of the connection plug and its surroundings according to this embodiment.

[0029] Figure 5 It is a diagram showing an example of screen display in this embodiment.

[0030] Figure 6 It is a diagram showing an operation button group according to this embodiment.

[0031] Figure 7 It is a diagram showing a connection mechanism according to this embodiment.

[0032] Figure 8 It is a diagram showing a connection pattern of this embodiment.

[0033] Fig. 9 It is a diagram showing the correction timing of this embodiment.

[0034] Fig.10 It is a schematic diagram showing a state where the bracket component of this embodiment is placed and a diagram showing the shape of the bracket component.

[0035] Explanation of symbols

[0036] 100: Liquid analysis device

[0037] 2: Sensor unit

[0038] 21: Sensor unit

[0039] 22: Conversion Department

[0040] 3: Device body

[0041] P1~P3: Connection port

[0042] 3e: Correction Department

[0043] 3b: Sensor recognition unit

[0044] 212: Connecting plug

[0045] 5: Metal shield

[0046] 6: Connection mechanism

[0047] 7: Notification Department

[0048] 8: Bracket parts DETAILED DESCRIPTION

[0049] Hereinafter, a liquid analysis device according to an embodiment of the present invention will be described with reference to the drawings.

[0050] <1. Device structure>

[0051] The liquid analyzer 100 of the present embodiment measures predetermined measurement items of a liquid to be measured, such as environmental water in rivers, swamps, lakes, and oceans, industrial water, and water in sewage treatment.

[0052] Here, as the measurement target items, there can be cited values ​​indicating the properties of the liquid including pH, electrical conductivity (EC), dissolved oxygen (DO), oxidation-reduction potential (ORP), ion concentrations of calcium, potassium, etc., turbidity, the amount of chlorophyll, cyanobacteria, etc. cells, nitrate concentration, and ammonium concentration, water depth, water level, etc. It should be noted that the following describes a liquid analysis device 100 capable of measuring the three measurement target items of pH, electrical conductivity (EC), and dissolved oxygen (DO).

[0053] Specifically, the liquid analysis device 100 is an immersion type used in, for example, on-site measurement. Figure 1 and Figure 2 As shown, the device includes a sensor unit 2 immersed in liquid for measuring a predetermined measurement target item and a device body 3 connected to the sensor unit 2. In this embodiment, the sensor unit 2 and the device body 3 are connected by a cable C for signal transmission and power supply.

[0054] Each part is described below.

[0055] <2.Sensor unit>

[0056] In the present embodiment, a sensor cell 2 for pH measurement, a sensor cell 2 for EC measurement, and a sensor cell 2 for DO measurement are provided.

[0057] Each sensor unit 2 is particularly Figure 3As shown in FIG. 1 , the sensor unit 21 is provided with: a sensor unit 21 that contacts a liquid and outputs an analog signal corresponding to a predetermined measurement target item; and a conversion unit 22 that converts the analog signal obtained by the sensor unit 21 into a digital signal. Figure 3 The sensor unit 2 for pH measurement is shown in FIG. Figure 2 As shown, each sensor unit 2 is used by a user holding the conversion unit 22. More specifically, the sensor unit 2 is immersed in liquid while the user holds the conversion unit 22, so that the sensor unit 21 contacts the liquid.

[0058] The sensor unit 21 is provided with components for measuring a measurement target item in accordance with the measurement target item.

[0059] For example, when the sensor unit 21 is a pH sensor for measuring pH as a measurement object, a glass electrode for pH measurement, a comparison electrode, a reference electrode, a temperature compensation electrode, etc. are provided. When the sensor unit 21 is an EC sensor for measuring EC as a measurement object, two electrodes or four electrodes for EC measurement are provided. In addition, when the sensor unit 21 is a DO sensor for measuring DO as a measurement object, a sensitive film that emits fluorescence in an amount depending on oxygen concentration, a light source for irradiating the sensitive film with excitation light for exciting fluorescence, and a light detector for receiving fluorescence emitted by the sensitive film are provided. In these sensor units 21, components for measuring the measurement object are held inside a support tube 211, for example, in a straight tube shape.

[0060] The conversion unit 22 converts the analog signal obtained by the sensor unit 21 into a digital signal. Specifically, the conversion unit 22 includes: an amplifier for amplifying the analog signal of the sensor unit 21; and an AD converter for digitally converting the amplified analog signal. The conversion unit 22 is dedicated to each sensor unit. In other words, when the sensor unit 21 is a pH sensor, the conversion unit 22 is for the pH sensor; when the sensor unit 21 is an EC sensor, the conversion unit 22 is for the EC sensor; and when the sensor unit 21 is a DO sensor, the conversion unit 22 is for the DO sensor.

[0061] In each conversion unit 22, an amplifier and an AD converter are provided on a circuit substrate 221, and the circuit substrate 221 is accommodated in a frame 222 of the conversion unit 22. A cable C electrically connected to the circuit substrate 221 is connected to the upper end of the frame 222, and a digital signal obtained by the conversion unit 22 is transmitted to the device body 3 via the cable C.

[0062] And, if Figure 3 As shown, the sensor unit 2 of the present embodiment is configured to be detachable at the sensor portion 21 and the conversion portion 22 .

[0063] Here, a connection plug 212 for electrically connecting to the conversion unit 22 is provided at the upper end of the support tube 211 of the sensor unit 21. The connection plug 212 is as shown in FIG. Figure 4 As shown, the sensor unit 21 is electrically connected to the wiring 21w by, for example, welding. In addition, an insertion portion 223 for inserting the connection plug 212 is formed at the lower end of the frame 222 of the conversion unit 22. By inserting the connection plug 212 of the sensor unit 21 into the insertion portion 223, the connection plug 212 is brought into contact with the connection terminal 221x provided on the circuit substrate 221 inside the frame 222 and electrically connected.

[0064] In addition, the sensor part 21 and the conversion part 22 are provided with a sealing mechanism 4 for sealing in a liquid-tight manner when they are connected. The sealing mechanism 4 includes an O-ring (not shown) between the frame 222 of the conversion part 22 and the support tube 211 of the sensor part 21, and a fastening structure 41 for pressing the O-ring through the frame 222 and the support tube 211. The fastening structure 41 includes, for example, a threaded portion provided on the outer peripheral surface of the frame 222 and a nut portion provided on the support tube 211 and screwed to the threaded portion. The sealing mechanism 4 ensures the liquid-tightness of the connection portion between the sensor part 21 and the conversion part 22, and makes the connection between the sensor part 21 and the conversion part 22 stable.

[0065] Here, in the sensor section 21, electromagnetic noise is superimposed on the analog signal at the connection portion between the connection plug 212 and the wiring 21w of the sensor section 21. In particular, when the user holds the sensor unit 2, as described above, the user holds the conversion section 22, or holds the connection portion between the sensor section and the conversion section 22. In this way, static electricity from the hand causes electromagnetic noise to be superimposed on the analog signal. This problem becomes particularly significant when the sensor section 21 is a pH sensor, and the SN of the pH sensor deteriorates. Therefore, in this embodiment, as Figure 4 As shown, a metal shield 5 is provided at the connection portion between the connection plug 212 and the wiring 21w in the pH sensor. The metal shield 5 is, for example, a cylindrical brass tube and is provided so as to surround the connection portion. It should be noted that the metal shield 5 may also be provided at other sensor parts 21.

[0066] <3. Device body>

[0067] The device main body 3 connected to the sensor unit 2 configured as above has a measurement value calculation unit 3a (see FIG. 1 ) for calculating the measurement value of each measurement target item based on the digital signal acquired from the connected sensor unit 2. Figure 2 ). In addition, Figure 1As shown, the front of the device body 3 has: a display 31 for displaying the measurement results of the connected sensor unit 2; and an operation button group 32 for controlling the connected sensor unit 2 or for switching the display of the display. It should be noted that the device body 3 is a computer having a CPU, an internal memory, an input and output interface, etc. In addition, Figure 1 Reference numeral 34 denotes an output port for printing and a cover for protecting the USB port.

[0068] The measurement result is displayed on the display 31 by the display control unit 3 b of the device body 3 . Figure 5 2 shows an example of screen display by the display control unit 3b. Figure 5 (a) is a display screen showing the measurement results when a pH sensor is connected to the device body 3 . Figure 5 (b) is a display screen showing the measurement results when the pH sensor and the EC sensor are connected to the device body 3 . Figure 5 (c) is a display screen showing the measurement results when the pH sensor, EC sensor, and DO sensor are connected to the device body 3. Figure 5 (b) and Figure 5 In (c), when a plurality of sensors are connected, the display screen is divided and a plurality of measurement target items are displayed at a glance. However, each measurement target item may be displayed in a switching manner, and the number of items to be displayed may be set.

[0069] In addition, if Figure 6 As shown, the operation button group 32 includes: a "calibration (CAL) button" for starting calibration, a "measurement (MEAS) button" for starting measurement, a "data (DATA) button" for displaying historical data, a "mode (MODE) button" for changing measurement parameters during measurement, a "set (SET) button" for making settings such as display display, an "enter (ENT) button" for confirming the measurement value recorded during measurement or calibration, "up, down, left, right, and right movement buttons", and a "power (POWER) button" for turning the power on / off.

[0070] <4. Automatic sensor recognition>

[0071] In addition, the device body 3 is provided with a plurality of (here, three) connection ports P1 to P3 in such a manner that a plurality of sensor units 2 having different measurement target items can be connected simultaneously. These three connection ports P1 to P3 are of the same shape and can connect the three sensor units 2 (conversion units 22) without distinction. In other words, any one of the three conversion units 22 can be connected to the first connection port P1, any one of the three conversion units 22 can be connected to the second connection port P2, and any one of the three conversion units 22 can be connected to the third connection port P3. It should be noted that the connection terminals of the cables C respectively connected to the three conversion units 22 also have the same shape in coordination with the connection ports P1 to P3.

[0072] Furthermore, the device body 3 has a sensor recognition unit 3c for recognizing the sensor unit 21 attached to the conversion unit 22 connected to each of the connection ports P1 to P3. Here, the sensor recognition unit 3c has a database including identifiers set in each of the conversion units 22 and the types of sensors associated with the identifiers, obtains the identifiers set in the conversion units 22 from the conversion units 22 connected to the connection ports P1 to P3, and recognizes the sensor units 21 connected to the connection ports P1 to P3 based on the database.

[0073] <5. Connection mechanism>

[0074] Furthermore, the liquid analysis device 100 of the present embodiment includes a connection mechanism 6 that connects the plurality of conversion sections 22 to each other.

[0075] The connection mechanism 6 connects the plurality of conversion parts 22 so that the sensor parts 21 mounted thereon face the same direction. Specifically, the connection mechanism 6 is composed of a recessed portion 61 formed on the side of each conversion part 22 and a convex portion 62 embedded in the recessed portion 61. Here, the recessed portion 61 is a groove extending in the up-down direction, and its upper end is open. In addition, the convex portion 62 is a convex strip slidably embedded in the groove. Thus, by sliding the convex portion 62 of one of the two conversion parts 22 in the recessed portion 61 of the other conversion part 22, the two conversion parts 22 can be connected.

[0076] In this embodiment, each conversion portion 22 has a concave portion 61 formed on the corresponding side surfaces (left and right side surfaces), and a convex portion 62 formed on the back surface. In this way, by forming the concave portion 61 and the convex portion 62, the three conversion portions 22 can be connected in a horizontal row (see Figure 8 (A)), it is also possible to connect the three conversion parts 22 in a right angle (L shape) (refer to Figure 8 (B)).

[0077] exist Figure 7The structure in which the conversion part 22 is connected by sliding up and down is adopted, but the structure in which the formation direction of the recessed part 61 and the convex part 62 is changed, so as to slide in a lateral direction, for example, or slide in an inclined direction can also be adopted.

[0078] In addition, the connection mechanism 6 connects the plurality of conversion parts 22 in such a manner that the sensor parts 21 respectively mounted on the plurality of conversion parts 22 are located at the same height. In other words, the connection mechanism 6 connects the plurality of conversion parts 22 in such a manner that at least one of the position from the bottom of the water to the sensing part or the position from the surface of the water to the sensing part in each sensor part 21 respectively mounted on the plurality of conversion parts 22 is located at the same position. Here, the sensing part of each sensor part 21 is a response membrane of a glass electrode in the case of a pH sensor, an electrode in the case of an EC sensor, and a sensing membrane in the case of a DO sensor. In the present embodiment, since the conversion parts 22 have the same shape and the sensor parts 21 have the same length, the sensor parts 21 are located at the same height position by connecting the plurality of conversion parts 22 using the connection mechanism 6.

[0079] It should be noted that the conversion section 22 can be connected and fixed to the device body 3 by forming a recessed portion 33 on the side surface of the device body 3 into which the convex portion 62 formed on the conversion section 22 is inserted (see Figure 1 ).

[0080] <6.Stable display function>

[0081] Furthermore, in the present embodiment, the conversion unit 22 includes the notification unit 7 for notifying that the output of the sensor unit 21 has stabilized during measurement and calibration.

[0082] The notification unit 7 notifies by light whether the output of the sensor unit 21 is stable. Specifically, the notification unit 7 is a lamp such as an LED that is exposed and provided on the front of the housing 222 of the conversion unit 22. For example, the notification unit 7 is controlled to light up (flash) intermittently before the output of the sensor unit 21 (i.e., the measured value obtained by the sensor unit 2) is stable, and to light up continuously when the output of the sensor unit 21 is already stable. The lighting control can be performed by a control unit (not shown) provided on the circuit board of the conversion unit 22, or by a measurement control unit 3d provided on the device body 3.

[0083] As for the stable display function, the display control unit 3b of the device body 3 has a hold function that automatically fixes the measured value displayed on the display 31 after the measured value obtained by the sensor unit 2 has stabilized. If the difference between the measured value during the hold and the measured value after the hold is greater than a predetermined value, the hold function is automatically released. Alternatively, the user can manually release the hold function by pressing a "MEAS button" or the like.

[0084] In addition, the notification unit 7 is configured to be intermittently lit (flashed) by connecting the conversion unit 22 to the device body 3 via the cable C, so that power is supplied from the device body 3. Thus, it is also possible to know whether the conversion unit 22 is reliably connected to the device body 3 through the notification unit 7. It should be noted that the lighting during connection can be performed after the sensor recognition unit 3c recognizes the sensor unit 21. Thus, it can be known whether the sensor unit 21 is recognized after the connection.

[0085] <7. Simultaneous calibration function>

[0086] The device body 3 of the present embodiment is configured to be able to calibrate a plurality of sensor units 21 having different measurement items at the same time. In other words, the present embodiment is configured to be able to calibrate three sensors, namely, a pH sensor, an EC sensor, and a DO sensor at the same time.

[0087] Specifically, the device body 3 has a calibration unit 3e for simultaneously calibrating a plurality of sensor units 21 with different measurement target items. The pH sensor is immersed in a calibration solution for a pH sensor, the EC sensor is immersed in a calibration solution for an EC sensor, and the DO sensor is exposed to air. In this way, each sensor unit 21 is calibrated using calibration substances such as calibration solutions of different types. Furthermore, by pressing an operation button ("calibration (CAL) button") of the device body 3, the calibration is performed as follows. Fig. 9 As shown, calibration of each sensor unit 21 is started simultaneously. By starting calibration, an analog signal is output from each sensor unit 21 and converted into a digital signal by the conversion unit 22. Then, the measurement value represented by the digital signal is calculated by the measurement value calculation unit 3a of the device body 3. The calibration unit 3e calibrates each sensor based on the measurement value obtained by the measurement value calculation unit 3a and the value of each calibration liquid. In this way, calibration processing for each sensor unit 21 after the calibration is started is performed in parallel.

[0088] Here, the calibration unit 3e can also automatically identify the calibration liquid based on the measured value obtained during calibration. Specifically, the calibration unit 3e has a calibration liquid database, compares the measured value obtained during calibration with the database, thereby determining the calibration liquid used for calibration, and performs calibration using the determined calibration liquid value.

[0089] <8. Bracket parts>

[0090] In addition, if Fig.10As shown, in the present embodiment, the device body 3 is provided with a stand member 8 that supports the device body 3 in an inclined or upright state. The stand member 8 is provided so as to be stored on the back side (the side opposite to the front side where the display 31 is provided) of the device body 3. The stand member 8 is provided so as to be rotatable between a storage position stored on the back side of the device body 3 and a support position that supports the device body 3 in an inclined or upright state.

[0091] In addition, the cable C is wound around the bracket member 8. Fig.10 In (B), an example is shown in which the cable C is wound around both the bracket member 8 and the device body 3, but the cable C may be wound around only the bracket member 8. It should be noted that by forming a recessed portion on the side of the bracket member 8, the volume of the cable C can be reduced in a state of being wound around the bracket member 8.

[0092] <9. Effects of the present embodiment>

[0093] According to the liquid analysis device 100 of the present embodiment configured in this way, since the sensor unit 21 and the conversion unit 22 are configured to be attachable to and detachable from each other, when the sensor unit 21 is replaced, only the sensor unit 21 is replaced without replacing the conversion unit 22, thereby reducing the running cost of the liquid analysis device 100. In addition, since the metal shield 5 is provided at the connection portion between the connection plug 212 and the wiring 21w of the sensor unit 21, electromagnetic noise superimposed on the analog signal from the connection portion between the connection plug 212 and the wiring 21w of the sensor unit 21 can be reduced, thereby improving the measurement accuracy.

[0094] <10. Other Modified Embodiments>

[0095] It should be noted that the present invention is not limited to the above-mentioned embodiments.

[0096] For example, in the above-described embodiment, the device body 3 and the sensor unit 2 are connected by a cable, but the device body 3 and the sensor unit 2 may be connected wirelessly.

[0097] In addition, the device body 3 may have a voice recognition function. Specifically, the device body 3 may be configured to have a voice recognition unit, and if the user makes a voice such as "measurement" or "calibration", the voice is recognized and measurement or calibration is performed. This voice recognition function is particularly effective when the device body 3 and the sensor unit 2 are located far apart and the user cannot operate the device body 3 and the sensor unit 2 at the same time.

[0098] In the above embodiment, the device body 3 obtains the digital signal from the sensor unit 2 to calculate the measurement value, but the measurement value may be calculated by the conversion unit 22. In this case, in the device body 3, the digital signal indicating the measurement value is sent to the device body.

[0099] In addition, in the above-mentioned embodiment, the connection mechanism 6 connects the plurality of conversion parts 22 so that the sensor parts 21 installed thereon face the same direction. In this way, when the plurality of conversion parts 22 are connected by the connection mechanism 6, the user holds the cables C connected to the conversion parts 22 to use the plurality of sensor units 2. More specifically, the sensor parts 21 are brought into contact with the liquid by immersing the plurality of sensor units 2 in the liquid while the user holds the cables C in one hand. As a result, at least one of the positions of the sensor parts 21 from the bottom of the water to the sensing part or from the surface of the water to the sensing part becomes the same position in the water. Therefore, the liquid analysis device 100 does not require the user to adjust the positions of the sensor units 2 in the water.

[0100] In the above embodiment, the liquid analyzer 100 is exemplified as measuring items such as pH, EC, and DO. However, by connecting the sensor unit 2 for measuring other measuring items to the device body 3, measuring items other than pH, EC, and DO can also be measured.

[0101] Furthermore, various modifications and combinations of the embodiments may be made without departing from the spirit of the present invention.

Claims

1. A liquid analysis device, characterized in that: have: a sensor portion that contacts the liquid and outputs an analog signal corresponding to a predetermined measurement target item; a conversion unit that converts the analog signal obtained by the sensor unit into a digital signal; as well as The device body is connected to the conversion unit by wire or wirelessly to obtain the digital signal from the conversion unit. The sensor unit and the conversion unit are configured to be detachable from each other. The sensor unit has a connection plug for electrically connecting to the conversion unit. A metal shield is provided at a connection portion between the connection plug and the wiring of the sensor unit. The liquid analysis device includes a plurality of connection mechanisms, and the plurality of connection mechanisms connect and fix the plurality of conversion parts to each other by bringing the side surfaces of the plurality of conversion parts, each of which has a sensor part mounted thereon, into direct contact with each other. The connection mechanism includes a recessed portion formed on a side surface of each of the conversion portions and a protruding portion fitted into the recessed portion.

2. The liquid analysis device according to claim 1, characterized in that: In each of the conversion parts, the concave portion is formed on the left and right side surfaces, respectively, and the convex portion is formed on the back surface of each of the conversion parts.

3. The liquid analysis device according to claim 1, characterized in that: The sensor unit and the conversion unit are integrated in a state of being electrically connected by the connection plug, and are operated in a hand-held manner.

4. The liquid analysis device according to claim 2, characterized in that: The sensor unit and the conversion unit are integrated in a state of being electrically connected by the connection plug, and are operated in a hand-held manner.

5. The liquid analysis device according to claim 3, characterized in that: The liquid analysis device comprises a plurality of the sensor units. The metal shield is provided on a sensor portion that measures pH as a measurement object item.

6. The liquid analysis device according to claim 4, characterized in that: The liquid analysis device comprises a plurality of the sensor units. The metal shield is provided on a sensor portion that measures pH as a measurement object item.

7. The liquid analysis device according to any one of claims 1 to 4, characterized in that: The conversion unit includes a notification unit that notifies that the output of the sensor unit has stabilized during measurement and calibration.

8. The liquid analysis device according to claim 7, characterized in that: The connection mechanism connects the plurality of conversion parts so that at least one of the positions from the bottom of the water to the sensing part or the positions from the surface of the water to the sensing part of the sensor parts respectively mounted on the plurality of conversion parts becomes the same position.

9. The liquid analysis device according to any one of claims 1 to 4, characterized in that: The device body connects a plurality of the conversion units to which a plurality of the sensor units having different measurement target items are mounted. The apparatus main body includes a calibration unit that simultaneously calibrates the plurality of sensor units having different measurement target items.

10. The liquid analysis device according to claim 9, characterized in that: The apparatus body calibrates the plurality of sensor units having different measurement target items using calibration substances of different types.

11. The liquid analysis device according to any one of claims 1 to 4, characterized in that: The device main body includes: a connection port to which a cable extending from the conversion section is connected; and a sensor recognition section to recognize a sensor section attached to the conversion section connected to the connection port.

12. The liquid analysis device according to any one of claims 1 to 4, characterized in that: The device body is provided with a support member for supporting the device body in an inclined or upright state. The bracket member is configured to be able to wind up a cable connecting the conversion unit and the device body.

13. A sensor unit, characterized in that: have: a sensor unit that contacts the liquid and outputs an analog signal corresponding to a predetermined measurement target item; and a conversion unit that converts the analog signal obtained by the sensor unit into a digital signal and outputs it to the outside, The sensor unit and the conversion unit are configured to be detachable from each other. The sensor unit has a connection plug for electrically connecting to the conversion unit. A metal shield is provided at a connection portion between the connection plug and the wiring of the sensor unit. The sensor unit has a plurality of connection mechanisms that connect and fix the plurality of conversion parts to each other by bringing the side surfaces of the plurality of conversion parts, on which the sensor parts are respectively mounted, into direct contact with each other. The connection mechanism includes a recessed portion formed on a side surface of each of the conversion portions and a protruding portion fitted into the recessed portion.

14. The sensor unit according to claim 13, characterized in that In each of the conversion parts, the concave portion is formed on the left and right side surfaces, respectively, and the convex portion is formed on the back surface of each of the conversion parts.

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