Conductivity detection device, detection method and ultrapure water circulation system

Abstract

The invention provides a conductivity detection device, a detection method and an ultrapure water circulation system. The detection device comprises a control module, a signal acquisition sub-module and a probe interface sub-module, the probe interface sub-module is respectively connected with the probe pair and the temperature detection unit; the probe pair is used for acquiring a conductivity signal of a medium based on a control signal sent by the control module, and the temperature detection unit is used for acquiring a temperature signal of the medium; the signal acquisition sub-module comprises a signal acquisition circuit, and the signal acquisition circuit outputs the conductivity signal to the control module through operational amplification; and the control module is used for receiving the conductivity signal and the temperature signal, and determining the conductivity after temperature compensation based on a compensation relation according to the conductivity signal and the temperature signal. According to the embodiment of the invention, automatic compensation of the conductivity can be realized, and the detection efficiency is improved. The method can be widely applied to the technical field of conductivity measurement.

Description

Technical Field

[0001] The invention relates to the technical field of conductivity measurement, in particular to a conductivity detection device and detection method, and an ultrapure water circulation system. Background Art

[0002] In an electrochemical energy conversion device (such as a fuel cell or an electrolytic cell), ultrapure water needs to be provided to the device to participate in the reaction, and there are strict restrictions on the conductivity of ultrapure water. If the conductivity of ultrapure water is too high, the life of the reactor in the device will be reduced. In order to monitor the conductivity of ultrapure water provided to the electrochemical energy conversion device at all times, a conductivity detection module is usually set in the device.

[0003] The conductivity of aqueous solutions is greatly affected by temperature. Common conductivity detection modules are all based on room temperature 25°C for collection. If the ambient temperature is too high or too low, the conductivity data will have a large error. Especially in the application scenario of electrochemical energy conversion devices, the ambient temperature often deviates from room temperature, which ultimately leads to a large error between the conductivity signal collected by the conductivity detection module and the actual conductivity. The electrochemical energy conversion device cannot make accurate countermeasures based on this, which affects the life of the reactor. In related technologies, manual temperature compensation is usually used to manually calculate and correct the conductivity through relevant compensation coefficients. This solution relies on manual labor and is inefficient. Summary of the invention

[0004] The purpose of the present invention is to solve one of the technical problems existing in the related art to at least a certain extent.

[0005] To this end, an object of the embodiments of the present invention is to provide an efficient conductivity detection device and detection method, and an ultrapure water circulation system.

[0006] In order to achieve the above technical purpose, one aspect of the embodiment of the present invention provides a conductivity detection device, including: a control module, a signal acquisition submodule and a probe interface submodule; the probe interface submodule is connected to a probe pair and a temperature detection unit respectively; the probe pair is used to collect the conductivity signal of the medium based on the control signal sent by the control module, and the temperature detection unit is used to collect the temperature signal of the medium; the signal acquisition submodule includes a signal acquisition circuit, and the signal acquisition circuit outputs the conductivity signal to the control module through operational amplification; the control module is used to receive the conductivity signal and the temperature signal, and determine the conductivity after temperature compensation based on the conductivity signal and the temperature signal based on the compensation relationship; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity. The conductivity detection device provided in the embodiment of the present application performs temperature compensation on the conductivity signal collected by the probe pair according to the temperature signal collected by the temperature detection unit, thereby improving the accuracy of the conductivity. The embodiment of the present application can realize automatic compensation of conductivity and improve detection efficiency.

[0007] In addition, the conductivity detection device according to the above embodiment of the present invention may also have the following additional technical features:

[0008] Furthermore, in one embodiment of the present invention, the detection device also includes a switch submodule, the control signal is a DC square wave signal, and the signal acquisition submodule is used to output a conductivity acquisition signal to the switch submodule; the switch submodule is used to output an AC square wave signal to the probe pair based on the DC square wave signal and the conductivity acquisition signal, so that the probe pair collects the conductivity signal of the medium.

[0009] Further, in one embodiment of the present invention, the signal acquisition circuit includes a first operational amplifier and a second operational amplifier; the first operational amplifier includes a first non-inverting input terminal, a first inverting input terminal and a first output terminal, and the second operational amplifier includes a second non-inverting input terminal, a second inverting input terminal and a second output terminal;

[0010] A first reference voltage is connected to the first non-inverting input terminal, the first inverting input terminal is connected to the probe pair, and the first inverting input terminal is connected to the first output terminal through a first resistor; the first non-inverting input terminal is connected to the second inverting input terminal through a second resistor, the second inverting input terminal is connected to the second output terminal through a third resistor, the first output terminal is connected to the second non-inverting input terminal through a fourth resistor, the second non-inverting input terminal is connected to a second reference voltage through a fifth resistor, and the second output terminal is connected to the control module.

[0011] Furthermore, in one embodiment of the present invention, the switch submodule includes a switch circuit, and the switch circuit includes a switch chip; the first pin of the switch chip is connected to the control module for receiving the DC square wave signal; the second pin, the third pin and the fourth pin of the switch chip are grounded; the tenth pin of the switch chip is connected to the probe interface submodule through the first capacitor, and is connected to the probe pair through the probe interface submodule, the ninth pin of the switch chip is connected to the signal acquisition submodule, and the eighth pin of the switch chip is connected to the power supply.

[0012] Further, in one embodiment of the present invention, the compensation relationship is determined by fitting multiple groups of temperature signals, conductivity signals and first conductivity measured under the first medium with the same conductivity; the conductivity of the first medium is the first conductivity.

[0013] Furthermore, in one embodiment of the present invention, the control module is used to determine the conductivity after temperature compensation according to the following formula:

[0014] σ=f(x,y)=axy 2 +bxy+cx+dy 2 +ey+f;

[0015] Wherein: σ is the conductivity after temperature compensation, x is the conductivity digital signal value corresponding to the conductivity signal collected by the probe pair; y is the actual temperature value corresponding to the temperature signal;

[0016] a=a 1 ·a 2 , b=a 1 b 2 , c=a 1 ·c 2 , d = a 2 b 1 , e=b 1 b 2 , f = b 1 ·c 2 ;

[0017] V F is the reference voltage of the analog-to-digital converter inside the control module, N is the resolution of the analog-to-digital converter; L is the distance between the two probes of the probe pair, S is the cross-sectional area of ​​the space between the two probes; R 5 is the resistance of the first resistor, R 6 is the resistance of the second resistor, R 7 is the resistance value of the third resistor; V REF1 is the voltage value of the first reference voltage, V REF2 is the voltage value of the second reference voltage;

[0018] a 2 、b 2 and c 2 is a constant coefficient, and the constant coefficient is obtained based on fitting processing of multiple groups of temperature signals, conductivity signals and first conductivity measured under the first medium with the same conductivity; the conductivity of the first medium is the first conductivity.

[0019] On the other hand, an embodiment of the present application provides a conductivity detection method for the above-mentioned conductivity detection device, the method comprising:

[0020] Collect conductivity signals and temperature signals;

[0021] Based on the signal acquisition circuit, the conductivity signal is output to the control module through operational amplification;

[0022] According to the conductivity signal and the temperature signal, the conductivity after temperature compensation is determined based on a compensation relationship; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity.

[0023] Furthermore, in one embodiment of the present invention, the compensation relationship is determined by a compensation formula, the compensation formula includes a constant coefficient, and the constant coefficient is further determined by the following steps: collecting conductivity signals corresponding to the first medium at different temperatures to obtain n groups of correlation data between temperature and conductivity signals; determining the constant coefficient by dichotomy based on the first conductivity and the n groups of correlation data between the temperature and conductivity signals; the conductivity of the first medium is the first conductivity, n≥2 and is a positive integer.

[0024] On the other hand, the present invention provides an ultrapure water circulation system, comprising the above-mentioned conductivity detection device.

[0025] On the other hand, the present invention provides an energy converter, comprising the above-mentioned ultrapure water circulation system.

[0026] The advantages and beneficial effects of the present invention will be partly given in the following description, partly become apparent from the following description, or be understood through the practice of the present invention:

[0027] A conductivity detection device disclosed in an embodiment of the present application includes: a control module, a signal acquisition submodule and a probe interface submodule; the probe interface submodule is connected to a probe pair and a temperature detection unit respectively; the probe pair is used to acquire the conductivity signal of the medium based on the control signal sent by the control module, and the temperature detection unit is used to acquire the temperature signal of the medium; the signal acquisition submodule includes a signal acquisition circuit, and the signal acquisition circuit outputs the conductivity signal to the control module through operational amplification; the control module is used to receive the conductivity signal and the temperature signal, and determine the conductivity after temperature compensation based on the conductivity signal and the temperature signal based on the compensation relationship; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity. The conductivity detection device of the embodiment of the present application performs temperature compensation on the conductivity signal collected by the probe pair according to the temperature signal collected by the temperature detection unit, thereby improving the accuracy of the conductivity. The embodiment of the present application can realize automatic compensation of conductivity and improve detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic structural diagram of an embodiment of a conductivity detection device provided in the present application;

[0030] Figure 2 An electrical schematic diagram of an embodiment of the signal acquisition submodule provided in the present application;

[0031] Figure 3 An electrical schematic diagram of another embodiment of the signal acquisition submodule provided in the present application;

[0032] Figure 4 An electrical schematic diagram of an embodiment of a switch submodule provided in the present application;

[0033] Figure 5 An electrical schematic diagram of an embodiment of the probe interface submodule provided in the present application;

[0034] Figure 6 A schematic structural diagram of an embodiment of the ultrapure water circulation system provided in the present application. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the terms "length", "up", "down", "front", "back", "left", "right", "top", "inside", "outside", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. For the step numbers in the following embodiments, they are only set for the convenience of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0038] Ultrapure water (conductivity < 0.055uS / CM) is often needed in the fields of electronics, power, semiconductors, chemical engineering, and biomedicine. For example, in electrochemical energy conversion devices (such as fuel cells or electrolytic cells), ultrapure water needs to be provided to the device to participate in the reaction, and there are strict restrictions on the conductivity of ultrapure water. If the conductivity of ultrapure water is too high, the life of the reactor in the device will be reduced. In order to monitor the conductivity of ultrapure water provided to the electrochemical energy conversion device at all times, a conductivity detection module is usually set in the device.

[0039] The conductivity of aqueous solutions is greatly affected by temperature. Common conductivity detection modules are all based on collection at room temperature of 25°C. If the ambient temperature is too high or too low, the conductivity data will have too large an error. Especially in the application scenario of electrochemical energy conversion devices, the ambient temperature often deviates from room temperature, which ultimately leads to a large error between the conductivity signal collected by the conductivity detection module and the actual conductivity. The electrochemical energy conversion device cannot make accurate response measures based on this, which affects the life of the reactor.

[0040] Therefore, the present application proposes a conductivity detection device. Below, the conductivity detection device proposed in the present application is introduced in detail.

[0041] Specifically, the conductivity detection device proposed in this application includes:

[0042] Control module, signal acquisition submodule and probe interface submodule;

[0043] The probe interface submodule is connected to the probe pair and the temperature detection unit respectively; the probe pair is used to collect the conductivity signal of the medium based on the control signal sent by the control module, and the temperature detection unit is used to collect the temperature signal of the medium;

[0044] The signal acquisition submodule includes a signal acquisition circuit, which outputs the conductivity signal to the control module through operational amplification;

[0045] The control module is used to receive the conductivity signal and the temperature signal, and determine the conductivity after temperature compensation based on the conductivity signal and the temperature signal and the compensation relationship; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity.

[0046] In some possible implementations, the conductivity detection device of the embodiment of the present application collects the conductivity signal through a signal acquisition circuit including an operational amplifier, and performs temperature compensation on the conductivity signal according to the collected temperature signal, which can realize automatic acquisition and compensation and improve the detection efficiency. In some embodiments, the control module is connected to the probe interface submodule, and the control module is connected to the signal acquisition submodule. The above connection can be a physical connection or a wireless communication connection. The conductivity detection device of this solution can perform temperature compensation on the conductivity signal collected by the hardware in the module according to the change of ambient temperature, eliminate the influence of the ambient temperature change on the output conductivity value, and make the measurement more accurate.

[0047] Optionally, the conductivity detection device proposed in the present application also includes a switch sub-module, the control signal is a DC square wave signal, and the signal acquisition sub-module is used to output the conductivity acquisition signal to the switch sub-module; the switch sub-module is used to output an AC square wave signal to the probe pair based on the DC square wave signal and the conductivity acquisition signal, so that the probe pair collects the conductivity signal of the medium.

[0048] In some possible implementations, the detection device in the embodiment of the present application may further include a switch submodule, which is used to enable the probe pair to perform conductivity signal acquisition according to the control signal of the control module. In the embodiment of the present application, the signal acquisition submodule is connected to the probe interface submodule via the switch submodule, which may be a physical connection. It is understandable that the acquisition and output of the conductivity signal is determined by the circuit characteristics of the signal acquisition submodule, that is, the signal acquisition submodule outputs the conductivity acquisition signal (i.e. Figure 1 The NC signal in the embodiment shown is a command signal, and when the conductivity is collected by the command signal, the conductivity signal (i.e. Figure 1 The ADC signal in the illustrated embodiment (which can be understood as a detected conductivity analog signal) is transmitted to a control module, which receives the conductivity signal (expressed as a voltage signal), converts it into a digital voltage signal through an analog-to-digital converter, and performs compensation calculation on the digital signal representing the conductivity according to the temperature signal to obtain the compensated conductivity.

[0049] Optionally, in the conductivity detection device proposed in the present application, the signal acquisition circuit includes a first operational amplifier and a second operational amplifier; the first operational amplifier includes a first non-inverting input terminal, a first inverting input terminal and a first output terminal, and the second operational amplifier includes a second non-inverting input terminal, a second inverting input terminal and a second output terminal;

[0050] The first reference voltage is connected to the first non-inverting input terminal, the first inverting input terminal is connected to the probe pair, and the first inverting input terminal is connected to the first output terminal through the first resistor; the first non-inverting input terminal is connected to the second inverting input terminal through the second resistor, the second inverting input terminal is connected to the second output terminal through the third resistor, the first output terminal is connected to the second non-inverting input terminal through the fourth resistor, the second non-inverting input terminal is connected to the second reference voltage through the fifth resistor, and the second output terminal is connected to the control module.

[0051] In some possible implementations, reference Figure 1 and Figure 2 As shown, the embodiment of the present application realizes the acquisition of conductivity signal by matching the signal acquisition submodule with the probe pair. Specifically, the first inverting input terminal is connected to the probe pair through the switch submodule and the probe interface submodule. The electrical signal of conductivity is obtained through the hardware circuit, and the temperature compensation calculation of the conductivity signal is realized through the control module. It can be understood that Figure 1The main controller in the embodiment is the control module in the present application, and the NTC thermistor is the temperature detection unit in the embodiment of the present application. In some embodiments, the conductivity detection of multiple media or multiple positions of the same medium can be realized by multiple channels corresponding to multiple operational amplifiers in the operational amplifier chip. Of course, the number of channels of the switch chip in the switch submodule is adjusted accordingly. The connection principle of the signal acquisition circuit can be seen in Figure 2 and Figure 3 It should be noted that those skilled in the art can also use the operational amplifier unit in the operational amplifier chip to implement the function of the operational amplifier, and the present application does not limit the specific form of the operational amplifier.

[0052] Optionally, in the conductivity detection device proposed in the present application, the switch submodule includes a switch circuit, and the switch circuit includes a switch chip; the first pin of the switch chip is connected to the control module for receiving a DC square wave signal; the second, third and fourth pins of the switch chip are grounded; the tenth pin of the switch chip is connected to the probe interface submodule through the first capacitor, and is connected to the probe pair through the probe interface submodule, the ninth pin of the switch chip is connected to the signal acquisition submodule, and the eighth pin of the switch chip is connected to the power supply.

[0053] In some possible implementations, the electrical schematic diagram of the switch circuit is shown in Figure 4 As shown, the number of pins used in the switch chip is determined according to the number of probe pairs and temperature detection units. Figure 4 This corresponds to the connection method between two sets of probe pairs and two sets of temperature detection units.

[0054] Optionally, in the conductivity detection device proposed in the present application, the probe pair includes a first sub-probe pair and a second sub-probe pair, and the temperature detection unit includes a first temperature detection sub-unit and a second temperature detection sub-unit; the first pin of the switch chip is connected to the control module for receiving a DC square wave signal; the second, third and fourth pins of the switch chip are grounded; the tenth pin of the switch chip is connected to the probe interface sub-module through the first capacitor, and is connected to the first sub-probe pair through the probe interface sub-module, the ninth pin of the switch chip is connected to the signal acquisition sub-module, and the eighth pin of the switch chip is connected to the power supply; the fifth pin of the switch chip is connected to the control module for receiving a DC square wave signal (exemplarily, it can be a PWM signal); the sixth pin of the switch chip is connected to the probe interface sub-module through the second capacitor, and is connected to the second sub-probe pair through the probe interface sub-module; the seventh pin of the switch chip is connected to the signal acquisition sub-module.

[0055] Optionally, in the conductivity detection device proposed in the present application, the probe interface submodule includes an interface circuit, the interface circuit includes a socket, the first pin of the socket is connected to the power supply through a sixth resistor, the first end of the control module is connected to the first pin of the socket through a seventh resistor, the first pin of the socket is also connected to the first end of the temperature detection unit; the second end of the temperature detection unit is connected to the second pin of the socket; the first end of the probe pair is connected to the third pin of the socket, and the third pin of the socket is also connected to the switch submodule; the second end of the probe pair is connected to the fourth pin of the socket; the second pin of the socket and the fourth pin of the socket are both grounded.

[0056] In some possible implementations, it is understood that the probe pair includes two probes, the first end of the probe pair is used to characterize one probe, and the second end of the probe pair is used to characterize the other probe. The interface circuit is used to connect the temperature detection unit and the probes of the probe pair to the hardware circuit to realize the collection of temperature signals and conductivity signals and the transmission of control signals.

[0057] Optionally, in the conductivity detection device proposed in the present application, the probe interface submodule includes an interface circuit, and the interface circuit includes a socket; the conductivity detection device also includes two groups of probe pairs and two groups of temperature detection units;

[0058] The first pin of the socket is connected to the power supply through the sixth resistor, the first end of the control module is connected to the first pin of the socket through the seventh resistor, and the third pin of the socket is connected to the switch submodule; the first end of the first temperature detection subunit is connected to the first pin of the socket, and the second end of the first temperature detection subunit is connected to the second pin of the socket; the first end of the first sub-probe pair is connected to the third pin of the socket, and the second end of the first sub-probe pair is connected to the fourth pin of the socket; the second pin of the socket and the fourth pin of the socket are both grounded;

[0059] The eighth pin of the socket is connected to the power supply through the ninth resistor, the second end of the control module is connected to the eighth pin of the socket through the eighth resistor, and the sixth pin of the socket is connected to the switch sub-module; the first end of the second temperature detection sub-unit is connected to the eighth pin of the socket, and the second end of the second temperature detection sub-unit is connected to the seventh pin of the socket; the first end of the second sub-probe pair is connected to the sixth pin of the socket, and the second end of the second sub-probe pair is connected to the fifth pin of the socket; the fifth pin of the socket and the seventh pin of the socket are both grounded.

[0060] Optionally, in the conductivity detection device proposed in the present application, the probe pair includes a first sub-probe pair and a second sub-probe pair, and the temperature detection unit includes a first temperature detection sub-unit and a second temperature detection sub-unit; the first sub-probe pair and the first temperature detection sub-unit are used to collect signals of the first medium, and the second sub-probe pair and the second temperature detection sub-unit are used to collect signals of the second medium.

[0061] In some possible implementations, two probe pairs can also collect conductivity signals at multiple locations of the same medium. Of course, the present application embodiment does not limit the specific number of probe pairs and temperature detection units, and three or more probe pairs and temperature detection units can be set as needed.

[0062] Optionally, in the conductivity detection device proposed in the present application, the compensation relationship is determined by fitting multiple groups of temperature signals, conductivity signals and first conductivity measured under the first medium with the same conductivity; the conductivity of the first medium is the first conductivity.

[0063] Optionally, in the conductivity detection device proposed in the present application, the control module is used to determine the conductivity after temperature compensation according to the following formula:

[0064] σ=f(x,y)=axy 2 +bxy+cx+dy 2 +ey+f;

[0065] Wherein: σ is the conductivity after temperature compensation, x is the conductivity digital signal value corresponding to the conductivity signal collected by the probe pair; y is the actual temperature value corresponding to the temperature signal; (it can be understood that the signal directly collected by the probe pair is a conductivity analog signal, which can be converted into a corresponding conductivity digital signal through an analog-to-digital converter).

[0066] a=a 1 ·a 2 , b=a 1 b 2 , c=a 1 ·c 2 , d = a 2 b 1 , e=b 1 b 2 , f = b 1 ·c 2 ;

[0067] V F is the reference voltage of the analog-to-digital converter inside the control module, N is the resolution of the analog-to-digital converter; L is the distance between the two probes of the probe pair, S is the cross-sectional area of ​​the space between the two probes; R 5 is the resistance of the first resistor, R 6 is the resistance of the second resistor, R 7 is the resistance value of the third resistor; V REF1 is the voltage value of the first reference voltage, V REF2 is the voltage value of the second reference voltage;

[0068] a 2 、b 2and c 2 is a constant coefficient, which is obtained based on fitting processing of multiple groups of temperature signals, conductivity signals and first conductivity measured under the first medium with the same conductivity; the conductivity of the first medium is the first conductivity.

[0069] On the other hand, an embodiment of the present application provides a conductivity detection method for use in the above-mentioned conductivity detection device, the method comprising:

[0070] Collect conductivity signals and temperature signals;

[0071] Based on the signal acquisition circuit, the conductivity signal is output to the control module through operational amplification;

[0072] According to the conductivity signal and the temperature signal, the conductivity after temperature compensation is determined based on a compensation relationship; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity.

[0073] Optionally, the conductivity detection method proposed in the present application determines the conductivity after temperature compensation based on the compensation relationship according to the conductivity signal and the temperature signal, including:

[0074] σ=f(x,y)=axy 2 +bxy+cx+dy 2 +ey+f;

[0075] Where: σ is the conductivity after temperature compensation, x is the conductivity digital signal value corresponding to the conductivity signal collected by the probe pair; y is the actual temperature value corresponding to the temperature signal;

[0076] a=a 1 ·a 2 , b=a 1 b 2 , c=a 1 ·c 2 , d = a 2 b 1 , e=b 1 b 2 , f = b 1 ·c 2 ;

[0077] V F is the reference voltage of the analog-to-digital converter inside the control module, N is the resolution of the analog-to-digital converter; L is the distance between the two probes of the probe pair, S is the cross-sectional area of ​​the space between the two probes; R 5 is the resistance of the first resistor, R 6 is the resistance of the second resistor, R 7 is the resistance value of the third resistor; V REF1is the voltage value of the first reference voltage, V REF2 is the voltage value of the second reference voltage;

[0078] a 2 、b 2 and c 2 is a constant coefficient, which is obtained based on fitting processing based on multiple groups of temperature signals, digital voltage signals and first conductivity measured under the first medium with the same conductivity.

[0079] Optionally, in the conductivity detection method proposed in the present application, the compensation relationship is determined by a compensation formula, the compensation formula includes a constant coefficient, and the constant coefficient is further determined by the following steps:

[0080] The conductivity signals corresponding to the first medium at different temperatures are collected to obtain n sets of correlation data between the temperature and the conductivity signals; a constant coefficient is determined by dichotomy according to the first conductivity and the correlation data between the n sets of temperature and the conductivity signals; the conductivity of the first medium is the first conductivity, and n≥2 is a positive integer.

[0081] The conductivity detection device provided by the present application is described in detail below with a specific embodiment:

[0082] Reference Figure 1 As shown, the conductivity detection device provided by the present application (that is, the attached Figure 6 Conductivity detection module in the embodiment of the present application), including: a main controller (i.e., a control module in the embodiment of the present application), a switch submodule, a signal acquisition submodule, a probe interface submodule, a probe, the probe including a probe pair consisting of two probes and an NTC thermistor (i.e., a temperature detection unit in the embodiment of the present application);

[0083] The main controller is respectively connected to the signal acquisition submodule, the switch submodule and the probe interface submodule, the switch submodule is respectively connected to the signal acquisition submodule and the probe interface submodule, the probe pair is connected to the probe interface submodule, and the NTC temperature sensitive resistor is connected to the probe interface submodule; so that the switch submodule can receive the switch control signal from the main controller (i.e., the control signal in the embodiment of the present application, illustratively, it can be a DC square wave signal) and the voltage signal from the signal acquisition submodule (i.e., the conductivity acquisition signal NC in the embodiment of the present application), the probe pair can receive the voltage signal PROBE (i.e., the AC square wave signal in the embodiment of the present application) from the switch submodule through the probe interface submodule, and the main controller can receive the conductivity analog signal ADC (i.e., the conductivity signal in the embodiment of the present application) from the signal acquisition submodule and the temperature signal TEMP (i.e., the temperature signal in the embodiment of the present application) from the probe interface submodule. Wherein, the main controller can perform temperature compensation on the conductivity signal collected by the probe pair according to the temperature signal collected by the temperature detection unit.

[0084] It is understandable that the main controller sends a control signal to the switch submodule to put the switch submodule in a specific on state, so that the conductivity acquisition signal (voltage signal NC) output by the signal acquisition submodule can be sent to the probe pair connected to the probe interface submodule after modulation by the switch submodule, and at the same time, the signal acquisition submodule can send the collected conductivity analog signal to the main controller to realize the detection of conductivity. In addition, the probe interface submodule can send the temperature signal collected by the NTC thermistor to the main controller to realize the detection of temperature. Finally, the main controller can compensate and correct the conductivity signal according to the temperature signal to output the corrected conductivity value. The conductivity detection device of this scheme can perform temperature compensation on the conductivity signal collected by the hardware in the module according to the change of ambient temperature, eliminate the influence of the ambient temperature change on the output conductivity value, and make the measurement more accurate.

[0085] Furthermore, the probe pair can receive the conductivity acquisition signal generated by the conductivity detection device, and the conductivity acquisition signal is an AC square wave signal. At present, most conductivity detection devices use direct current to power the probe pair. Long-term use of direct current will cause the probe to polarize and adsorb scale, seriously affecting the measurement accuracy. The present application avoids the problem of probe polarization and scale adsorption by adopting an AC square wave signal.

[0086] Furthermore, assuming that the corrected conductivity value is σ, the digital voltage signal value corresponding to the conductivity analog signal is x, and the collected temperature value is y, then the functional relationship σ=f(x, y) is satisfied.

[0087] Furthermore, the functional relationship is σ=f(x,y)=axy 2 +bxy+cx+dy 2 +ey+f (i.e., the compensation relationship in the embodiment of the present application); wherein, an aqueous solution with the same conductivity is used at different ambient temperatures to test and obtain x, y and σ at different ambient temperatures, and then the constant coefficients a, b, c, d, e, and f in the function formula are calculated by dichotomy.

[0088] Further, the probe includes a first probe, wherein the first probe includes a first probe pair consisting of two probes and a first NTC thermistor;

[0089] The signal acquisition submodule has a signal acquisition circuit, which includes: an operational amplifier chip U2, which has a first channel U2A (i.e., the first operational amplifier in the embodiment of the present application) and a second channel U2B (i.e., the second operational amplifier in the embodiment of the present application), pins 1, 2, 3, 4, and 11 of the operational amplifier chip U2 are located on the first channel U2A, and pins 5, 6, and 7 of the operational amplifier chip U2 are located on the second channel U2B; resistor R5 (i.e., the first resistor in the embodiment of the present application), resistor R6 (i.e., the second resistor in the embodiment of the present application), resistor R7 (i.e., the third resistor in the embodiment of the present application), resistor R8 (i.e., the fourth resistor in the embodiment of the present application), and resistor R9 (i.e., the fifth resistor in the embodiment of the present application).

[0090] The 3rd pin of the operational amplifier chip U2 (i.e., the first positive input terminal in the embodiment of the present application) is connected to the reference voltage V REF1 (i.e., the first reference voltage in the embodiment of the present application) and one end of the resistor R6, pin 2 (i.e., the first inverting input end in the embodiment of the present application) is respectively connected to the switch submodule and one end of the resistor R5, pin 1 (i.e., the first output end in the embodiment of the present application) is respectively connected to the other end of the resistor R5 and one end of the resistor R8, pin 4 is connected to the power supply VCC, pin 11 is connected to the reference ground GND, pin 5 (i.e., the second positive input end in the embodiment of the present application) is respectively connected to the other end of the resistor R8 and one end of the resistor R9, and the other end of the resistor R9 is connected to the reference voltage V REF2 (i.e., the second reference voltage in the embodiment of the present application), pin 6 (i.e., the second inverting input terminal in the embodiment of the present application) is respectively connected to the other end of resistor R6 and one end of resistor R7, and pin 7 (i.e., the second output terminal in the embodiment of the present application) is respectively connected to the other end of resistor R7 and the main controller to output the conductivity analog voltage signal (i.e., the first conductivity signal) collected by the first probe pair in the first probe.

[0091] It can be understood that the two probes of the conductivity probe and the ultrapure water between them are equivalent to a variable resistor, R F The resistance of the conductivity probe is determined by the cross-sectional area S and spacing L of the probe, as well as the resistivity ρ of ultrapure water. The cross-sectional area S and spacing L are fixed values;

[0092] Reference voltage V REF1 Input the positive input terminal of the first channel U2A of the operational amplifier chip U2, and the resistor R5 is connected in parallel to the inverting input terminal and output terminal of U2A. The low voltage end of the resistor R5 is connected to the NC1 pin of the switch submodule. According to the "virtual short" characteristic of the operational amplifier, the NC1 voltage value is equal to V REF1The output of the op amp U2A is connected to the positive input of the op amp U2B. According to the "virtual disconnection" characteristic of the op amp, there is no current input to the positive and reverse inputs of U2B. The current path at the output of U2A flows through the resistor R5 and the equivalent variable resistor R of the first probe. F1 Then it goes to the reference ground GND to form a loop.

[0093] The voltage at the positive input terminal of the second channel U2B Inverting input voltage V - =V REF1 , let the resistor R 6 =R 8 , R 7 =R 9 , V REF2 is the positive phase bias voltage, then the output voltage of the second channel U2B is

[0094] V + and V - Substitute the voltage value of the conductivity analog voltage signal collected by the first probe into:

[0095]

[0096] because where ρ 1 Indicates the water resistivity measured by the first probe, water resistivity According to the conductivity is the reciprocal of resistivity, that is where σ 1 ' represents the water conductivity measured by the first probe, ignoring the influence of ambient temperature changes, that is, at a constant ambient temperature of 25°C: the water conductivity measured by the first probe is

[0097] Therefore, the temperature compensation process of conductivity provided in the embodiment of the present application is specifically as follows: the main controller receives the temperature analog voltage signal (i.e., the first temperature signal) collected by the first NTC thermistor, and compensates and corrects the first conductivity signal according to the first temperature signal and outputs the corrected first conductivity value; the corrected first conductivity value is σ 1 , the digital voltage signal value corresponding to the first conductivity signal is x 1 , the first temperature value corresponding to the first temperature signal is y 1 , then the functional relationship is satisfied:

[0098] σ 1 =f(x 1 ,y 1 )=ax 1 y 1 2 +bx 1 y 1 +cx1 +dy 1 2 +ey 1 +f;

[0099] Among them: a=a 1 ·a 2 , b=a 1 b 2 , c=a 1 ·c 2 , d = a 2 b 1 , e=b 1 b 2 , f = b 1 ·c 2 ;

[0100] V F is the reference voltage of the analog-to-digital converter ADC1 inside the main controller, N is the resolution of the analog-to-digital converter ADC1, the distance between the two probes of the first probe pair is L, and the cross-sectional area of ​​the space between the two probes is S.

[0101] The same conductivity water solution was used at different ambient temperatures to test the x 1 ,y 1 and σ 1 , and then calculate the constant coefficient a in the function formula by dichotomy 2 、b 2 and c 2 The numerical value of .

[0102] It is understandable that in actual use, since the conductivity of ultrapure water is affected by changes in the external ambient temperature, the conductivity value collected by the hardware circuit alone cannot meet the conductivity measurement requirements of high and low temperature working environments. Because the higher the temperature, the greater the conductivity value, this patent uses a conductivity temperature compensation algorithm to calculate the actual conductivity value through a fitting formula.

[0103] According to the conductivity analog voltage signal V of the first probe collected by the hardware circuit ADC1 , the conversion formula of the analog-to-digital converter ADC inside the main controller is: where x 1 is the digital AD value, V ADC1 is the analog conductivity voltage value, V F is the reference voltage of the analog-to-digital converter ADC inside the main controller, and N is the resolution of the analog-to-digital converter ADC inside the main controller;

[0104] A. First, determine the AD value x for the first probe at room temperature (25°C). 1 and conductivity σ1 The functional relationship is: 1 =σ 1 '=f(x 1 )=a 1 x 1 +b 1 ;

[0105] a 1 and b 1 According to the formula and We can get:

[0106] B. Then, determine the same AD value x 1 In this case, the ambient temperature of the first probe is y 1 and conductivity σ 1 The functional relationship is: 1 =f(y 1 )=a 2 y 1 2 +b 2 y 1 +c 2 , put ultrapure water into a high and low temperature box to simulate different ambient temperatures, and conduct long-term and multiple tests to obtain a large number of first probe ambient temperatures y 1 and conductivity σ 1 The constant coefficient a is calculated by dichotomy 2 、b 2 and c 2 The numerical value of .

[0107] Further, refer to Figure 3 As shown, the probe further includes a second probe, which includes a second probe pair consisting of two probes and a second NTC thermistor;

[0108] The signal acquisition circuit also includes resistors R10, R11, R12, R13, and R14. The operational amplifier chip U2 also has a third channel U2C and a fourth channel U2D. Pins 8, 9, and 10 of the operational amplifier chip U2 are located on the third channel U2C, and pins 12, 13, and 14 are located on the fourth channel U2D.

[0109] Pin 10 of the operational amplifier chip U2 is connected to the reference voltage V REF3 and one end of resistor R11, pin 9 is connected to the switch submodule and one end of resistor R10, pin 8 is connected to the other end of resistor R10 and one end of resistor R13, pin 12 is connected to the other end of resistor R13 and one end of resistor R14, and the other end of resistor R14 is connected to the reference voltage V REF4Pin 13 is respectively connected to the other end of resistor R11 and one end of resistor R12, and pin 14 is respectively connected to the other end of resistor R12 and the main controller to output the conductivity analog voltage signal (ie, the second conductivity signal) collected by the second probe pair.

[0110] It is understandable that in the conductivity detection device, multiple probes can be equipped to achieve multi-position conductivity detection. In the conductivity detection device of the present application, the hardware circuit active components only use a four-channel operational amplifier chip and a dual-channel analog switch chip to complete the signal acquisition of two conductivity probes, with high circuit integration and low cost.

[0111] Furthermore, the compensation process of the conductivity collected by the second probe is consistent with the conductivity compensation process of the first probe. Specifically, the main controller receives the temperature analog voltage signal (i.e., the second temperature signal) collected by the second NTC thermistor, and compensates and corrects the second conductivity signal according to the second temperature signal and outputs the corrected second conductivity value; assuming that the corrected second conductivity value is σ 2 , the digital voltage signal value corresponding to the second conductivity signal is x 2 , the second temperature value corresponding to the second temperature signal is y 2 , then the functional relationship is satisfied:

[0112] σ 2 =f(x 2 ,y 2 )=ax 2 y 2 2 +bx 2 y 2 +cx 2 +dy 2 2 +ey 2 +f;

[0113] Among them: a=a 1 ·a 2 , b=a 1 b 2 , c=a 1 ·c 2 , d = a 2 b 1 , e=b 1 b 2 , f = b 1 ·c 2 ;

[0114] V Fis the reference voltage of the analog-to-digital converter ADC2 inside the main controller, N is the resolution of the analog-to-digital converter ADC2, the distance between the two probes of the second probe pair is L, and the cross-sectional area of ​​the space between the two probes is S;

[0115] The same conductivity water solution was used at different ambient temperatures to test the x 2 ,y 2 and σ 2 , and then calculate the constant coefficient a in the function formula by dichotomy 2 、b 2 and c 2 The numerical value of .

[0116] Furthermore, the switch submodule has a switch circuit, and the switch circuit includes a switch chip U1, a first capacitor C1 and a second capacitor C2;

[0117] Reference Figure 4 As shown, pin 1 of the switch chip U1 is the signal input terminal of channel one and pin 5 is the signal input terminal of channel two, and they are connected to the main controller for communication, pin 3 is connected to the reference ground GND, pin 8 is the power supply terminal, connected to the power supply VCC, pin 2 is the normally open end of channel one, connected to the reference ground GND, pin 4 is the normally open end of channel two, connected to the reference ground GND, pin 9 is the normally closed end of channel one, connected to one end of the resistor R5 in the signal acquisition circuit, pin 7 is the normally closed end of channel two, connected to one end of the resistor R10 in the signal acquisition circuit, pin 10 is the common end of channel one, connected to one end of the first capacitor C1, pin 6 is the common end of channel two, connected to one end of the first capacitor C2, the other end of the first capacitor C1 is the output end of channel one, connected to the probe interface submodule, and the other end of the first capacitor C2 is the output end of channel two, connected to the probe interface submodule.

[0118] It can be understood that the main controller outputs a DC square wave PWM with a certain voltage amplitude, frequency and duty cycle to pins 1 and 5 of the switch chip U1, then the other end of the first capacitor C1 will output an AC square wave PROBE1 with a positive and negative amplitude of 1 / 2 of the voltage input to pin 9 of the U2 chip (i.e., half the NC1 voltage), and the same frequency and duty cycle as the PWM square wave, and the other end of C2 will output an AC square wave PROBE2 with a positive and negative amplitude of 1 / 2 of the voltage input to pin 7 of the U2 chip (i.e., half the NC2 voltage), and the same frequency and duty cycle as the PWM square wave.

[0119] Further, the probe interface submodule has an interface circuit, which includes: a socket J1, a resistor R1 (i.e., the sixth resistor in the embodiment of the present application), a resistor R2 (i.e., the seventh resistor in the embodiment of the present application), a resistor R3 (i.e., the eighth resistor in the embodiment of the present application), and a resistor R4 (i.e., the ninth resistor in the embodiment of the present application); refer to Figure 5As shown, the two ends of the first NTC temperature resistor (i.e., the first temperature detection unit in the embodiment of the present application) are respectively connected to pin 1 and pin 2 of the socket J1, and the two probes of the first probe pair are respectively connected to pin 3 and pin 4 of the socket J1; the two ends of the second NTC temperature resistor are respectively connected to pin 7 and pin 8 of the socket J1, and the two probes of the second probe pair are respectively connected to pin 5 and pin 6 of the socket J1; one end of the resistor R1 is connected to the power supply VCC, the other end of the resistor R1 is connected to pin 1 of the socket J1 and one end of the resistor R2, and the other end of the resistor R2 outputs the collected temperature analog voltage signal TEMP1 (first temperature signal) and is connected to the main controller; one end of the resistor R4 is connected to the power supply VCC, the other end of the resistor R4 is connected to pin 8 of the socket J1 and one end of the resistor R3, and the other end of the resistor R3 outputs the collected temperature analog voltage signal TEMP2 (second temperature signal) and is connected to the main controller.

[0120] The probe interface submodule in the embodiment of the present application is mainly used as an electrical connection interface of the probe, so that the probe can receive the acquisition signal and transmit the acquired signal to the main controller.

[0121] It can be known from the above description that the device provided by the present application includes: a control module, a signal acquisition submodule and a probe interface submodule; the probe interface submodule is respectively connected to a probe pair and a temperature detection unit; the probe pair is used to acquire the conductivity signal of the medium based on the control signal sent by the control module, and the temperature detection unit is used to acquire the temperature signal of the medium; the signal acquisition submodule includes a signal acquisition circuit, and the signal acquisition circuit outputs the conductivity signal to the control module through operational amplification; the control module is used to receive the conductivity signal and the temperature signal, and determine the conductivity after temperature compensation based on the conductivity signal and the temperature signal based on the compensation relationship; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity. The conductivity detection device provided in the embodiment of the present application performs temperature compensation on the conductivity signal collected by the probe pair according to the temperature signal collected by the temperature detection unit, thereby improving the accuracy of the conductivity. The embodiment of the present application can realize automatic compensation of conductivity and improve detection efficiency.

[0122] On the other hand, an embodiment of the present application provides an ultrapure water circulation system, including the conductivity detection device as described above.

[0123] Reference Figure 6 As shown, the ultrapure water circulation system provided in the embodiment of the present application may include:

[0124] Water supply port 1, water storage tank, water filtration module 10, ultrapure water outlet 14, conductivity detection module (i.e., conductivity detection device provided in the embodiment of the present application), water flow controller 11;

[0125] The water storage tank 6 has a first inlet, a second inlet and a first outlet, the first inlet is connected to the water supply port to receive water from the water supply port, the first outlet is connected to the input end of the water filtration module, the output end of the water filtration module is respectively connected to the second inlet and the input end of the water flow controller, and the output end of the water flow controller is connected to the ultrapure water outlet; wherein the first outlet, the water treatment module and the second inlet constitute a circulation loop, and the first outlet, the water treatment module, the water flow controller and the ultrapure water outlet constitute an output flow path;

[0126] The first probe 2 of the conductivity detection device is arranged between the water supply port and the first inlet, and is used to collect the conductivity σ1 of the water from the water supply port; and / or, the second probe 3 of the conductivity detection device is arranged between the output end of the water filtration module and the second inlet, and is used to collect the conductivity σ2 of the water output by the water filtration module. (both σ1 and σ2 are the conductivity values ​​after compensation and correction output by the conductivity detection module).

[0127] It can be understood that the ultrapure water circulation system of the present application enables the water in the water storage tank to form a purification circulation loop, thereby ensuring a stable supply of ultrapure water with conductivity that meets the requirements to the downstream application end, such as being provided to the electrochemical energy conversion device to participate in the reaction, thereby avoiding a reduction in the life of the reactor.

[0128] The water supplied by the water treatment system flows into the ultrapure water circulation system through the water supply port. The conductivity σ1 of the water from the water supply port and the conductivity σ2 of the water in the circulation loop are monitored by the conductivity detection device. The filtration and output of the water in the ultrapure water circulation system are controlled according to the conductivity σ1 and the conductivity σ2, thereby ensuring that the conductivity of the ultrapure water meets the requirements.

[0129] Furthermore, when the conductivity σ1>the first conductivity preset value, the system alarms.

[0130] Further, when the conductivity σ2 is less than the second conductivity preset value, the output flow path is controlled to be opened to output ultrapure water.

[0131] Furthermore, the ultrapure water circulation system also includes: a first liquid level switch 7 and a second liquid level switch 8; the first liquid level switch is arranged near the top of the water tank, and the second liquid level switch is arranged near the bottom of the water tank. When the liquid level switch contacts water, it is in a closed state, and when it does not contact water, it is in an open state, which is used to judge the water level state in the water tank.

[0132] It can be understood that the embodiment of the present application monitors the water level status in the water tank through the first liquid level switch and the second liquid level switch, and controls the filtration and output of water in the ultrapure water circulation system according to the water level status in the water tank, conductivity σ1 and conductivity σ2, thereby ensuring that the conductivity of the ultrapure water meets the requirements.

[0133] Furthermore, the ultrapure water circulation system further comprises: a circulation pump 9;

[0134] The circulation pump is arranged between the first outlet and the input end of the water filter module, and is used for pumping water out of the water storage tank and flowing it into the circulation loop.

[0135] Further, the water filtration module is an EDI module.

[0136] It is understandable that when the EDI module is working, it can remove the anions and cations in the water flowing through the module and reduce the conductivity of the water. Compared with the traditional method of using a deionized column to filter water, which requires frequent replacement of the filter module, the EDI used in this solution can be recycled and reused, greatly reducing costs.

[0137] Furthermore, the main controller is also in communication connection with the water filtration module, liquid level switch, water flow controller, and circulation pump of the ultrapure water circulation system.

[0138] The circulation mode of the ultrapure water circulation system used for electrochemical energy conversion device is:

[0139] The ultrapure water circulation system also includes: a first liquid level switch and a second liquid level switch; the first liquid level switch is arranged near the top of the water storage tank, and the second liquid level switch is arranged near the bottom of the water storage tank. When the liquid level switch contacts water, it is in a closed state, and when it does not contact water, it is in an open state, and is used to judge the water level state in the water storage tank;

[0140] Before the electrochemical energy conversion device is officially working (it should be noted that before officially working, the fuel cell has not started to generate electricity and the electrolytic cell has not started to produce hydrogen), the circulation method includes:

[0141] S1. When the first liquid level switch is disconnected and the second liquid level switch is disconnected, the water supply port injects water into the water storage tank, and the circulation loop and the output flow path are closed at the same time;

[0142] S2, when the first liquid level switch is disconnected and the second liquid level switch is closed, the water supply port is kept to continuously inject water into the water storage tank, the water filter module is controlled to start working and the circulation loop is opened, so that the water flowing out of the first outlet is filtered by the water filter module and flows back into the water storage tank to reduce the conductivity of the water in the water storage tank, while keeping the output flow path closed;

[0143] S3. When the first liquid level switch is closed and the second liquid level switch is closed, the water supply port is stopped from injecting water into the water tank, and the water filtration module and the circulation loop are kept open; the conductivity detection module is controlled to detect the conductivity σ2 of the water in the circulation loop in real time. When σ2 is less than the second conductivity preset value, the output flow path is controlled to open to output ultrapure water, and at the same time, the electrochemical energy conversion device begins to enter the formal working state.

[0144] In the embodiment of the present application, when the first liquid level switch is disconnected and the second liquid level switch is disconnected, the system determines that the water tank is short of water, and controls the water supply port to inject water into the water tank, but temporarily does not open the circulation loop and the output flow path; when the first liquid level switch is disconnected and the second liquid level switch is closed, the system determines that there is some water in the water tank, and controls the circulation loop to be opened and the water filtration module to be turned on, so that the water in the water tank enters the circulation loop and reduces the conductivity under the action of the water filtration module, and then flows back to the water tank. Starting the ultrapure water circulation before the water tank is full can effectively improve the system efficiency; in this stage , the conductivity of the water in the circulation loop and the water tank has not yet met the requirement, and the output flow path needs to be kept closed; when the first liquid level switch is closed and the second liquid level switch is closed, the system determines that the water tank is full of water, and will control the water supply port to stop supplying water to the water tank, and the water in the water tank continues to be filtered in the circulation loop to reduce the conductivity; when the conductivity detection device detects that the conductivity σ2 of the water in the circulation loop meets the requirement (for example, less than 0.055uS / CM), the system determines that the water quality is qualified, and will control the output flow path to be opened to supply ultrapure water to the reaction area of ​​the electrochemical energy conversion device.

[0145] The above circulation method has a high degree of automation and good reliability, ensuring a stable supply of ultrapure water with conductivity that meets the requirements to the electrochemical energy conversion device to participate in the reaction, thereby avoiding a reduction in the life of the reactor.

[0146] Further, in S1 and / or S2, the conductivity detection device is controlled to detect the conductivity σ1 of the water flowing from the water supply port to the water storage tank in real time, and when σ1>the first conductivity preset value, the system alarms.

[0147] Further, in S3, when σ2<the second conductivity preset value, the water filter module is turned off (water can still flow through the water filter module, but there is no filtering effect).

[0148] In the embodiment of the present application, when σ2 is less than the second conductivity preset value, the water conductivity in the water tank meets the standard and no filtering treatment is required, which can effectively save energy.

[0149] During the period when the electrochemical energy conversion device is in the formal working state (i.e. the fuel cell starts to generate electricity and the electrolytic cell starts to produce hydrogen), the circulation method includes:

[0150] S4. When the first liquid level switch is disconnected and the second liquid level switch is closed, the flow path between the water supply port and the water storage tank is kept closed, and the circulation loop and the output flow path are opened; the conductivity detection device is controlled to detect the conductivity σ2 of the water in the circulation flow path in real time, and when σ2> the second conductivity preset value, the water filtration module is started. It is understandable that if it is subsequently detected that σ2< the second conductivity preset value, the water filtration module is turned off.

[0151] In some embodiments, when the electrochemical energy conversion device is already in working condition, the ultrapure water circulation system is already outputting ultrapure water with conductivity that meets the standard to the device, and the water in the water tank is constantly decreasing. Before the second liquid level switch is disconnected, there is no need to re-supply water from the water supply port to the water storage tank, thereby ensuring a stable supply of ultrapure water with conductivity that meets the requirements to the electrochemical energy conversion device to participate in the reaction, thereby avoiding a reduction in the life of the reactor.

[0152] Furthermore, when the electrochemical energy conversion device is in a formal working state, the circulation method also includes:

[0153] S5. When the first liquid level switch is disconnected and the second liquid level switch is disconnected, the circulation loop and the output flow path are kept open, and the water supply port is opened to fill water into the water storage tank, and the water filtration module is started at the same time.

[0154] In an embodiment of the present application, when the first liquid level switch is disconnected and the second liquid level switch is disconnected, the system determines that the water level in the water tank is too low and needs to start the water supply to replenish water; although the conductivity of the water in the water tank will be increased after replenishment, since the electrochemical energy conversion device needs to maintain a working state, the output flow path also needs to maintain the output of ultrapure water, and therefore the water filtration module is turned on at the same time to filter the water in the circulation system to ensure that the conductivity of the water in the circulation system is reduced as soon as possible, thereby reducing the impact on the reactor life during the water tank replenishment process.

[0155] Furthermore, when the electrochemical energy conversion device is in a formal working state, the circulation method also includes:

[0156] S6. When the first liquid level switch is closed and the second liquid level switch is closed, the water supply port is stopped from injecting water into the water storage tank; the conductivity detection device detects that the conductivity of the water in the circulation loop is σ2, and when σ2 is less than the second conductivity preset value, the water filtration module is closed.

[0157] Furthermore, a circulation pump is provided between the first outlet and the input end of the water filtration module, for pumping water out of the water storage tank and flowing it into the circulation loop, that is, starting and closing the circulation flow path;

[0158] The water flow controller is used to start and stop the output flow path.

[0159] Of course, the conductivity detection device proposed in this application can also be used in ultrapure water circulation systems with other compositions / circulation modes, and this application does not make any specific limitations.

[0160] It can be seen that the contents of the above-mentioned device embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present system embodiments are the same as those of the above-mentioned device embodiments, and the beneficial effects achieved are also the same as those achieved by the above-mentioned device embodiments.

[0161] On the other hand, an embodiment of the present application provides an energy converter, comprising the ultrapure water circulation system as described above.

[0162] Similarly, the contents of the above-mentioned device embodiments are all applicable to the present converter embodiment. The functions specifically implemented by the present converter embodiment are the same as those of the above-mentioned device embodiments, and the beneficial effects achieved are also the same as those achieved by the above-mentioned device embodiments.

[0163] In the description of this specification, the description with reference to the terms "one embodiment", "another embodiment" or "certain embodiments" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0164] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A conductivity detection device, characterized in that: include: Control module, signal acquisition submodule and probe interface submodule; The probe interface submodule is connected to the probe pair and the temperature detection unit respectively; the probe pair is used to collect the conductivity signal of the medium based on the control signal sent by the control module, and the temperature detection unit is used to collect the temperature signal of the medium; The signal acquisition submodule includes a signal acquisition circuit, and the signal acquisition circuit outputs the conductivity signal to the control module through operational amplification; The control module is used to receive the conductivity signal and the temperature signal, and determine the conductivity after temperature compensation according to the conductivity signal and the temperature signal based on a compensation relationship; The compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity.

2. A conductivity detection device according to claim 1, characterized in that: The detection device also includes a switch submodule, the control signal is a DC square wave signal, and the signal acquisition submodule is used to output a conductivity acquisition signal to the switch submodule; the switch submodule is used to output an AC square wave signal to the probe pair based on the DC square wave signal and the conductivity acquisition signal, so that the probe pair can collect the conductivity signal of the medium.

3. A conductivity detection device according to claim 1, characterized in that: The signal acquisition circuit includes a first operational amplifier and a second operational amplifier; the first operational amplifier includes a first non-inverting input terminal, a first inverting input terminal and a first output terminal, and the second operational amplifier includes a second non-inverting input terminal, a second inverting input terminal and a second output terminal; A first reference voltage is connected to the first in-phase input terminal, the first inverting input terminal is connected to the probe pair, and the first inverting input terminal is connected to the first output terminal via a first resistor; The first non-inverting input terminal is connected to the second inverting input terminal through a second resistor, the second inverting input terminal is connected to the second output terminal through a third resistor, the first output terminal is connected to the second non-inverting input terminal through a fourth resistor, the second non-inverting input terminal is connected to a second reference voltage through a fifth resistor, and the second output terminal is connected to the control module.

4. A conductivity detection device according to claim 2, characterized in that: The switch submodule includes a switch circuit, and the switch circuit includes a switch chip; the first pin of the switch chip is connected to the control module for receiving the DC square wave signal; the second pin, the third pin and the fourth pin of the switch chip are grounded; the tenth pin of the switch chip is connected to the probe interface submodule through a first capacitor, and is connected to the probe pair through the probe interface submodule, the ninth pin of the switch chip is connected to the signal acquisition submodule, and the eighth pin of the switch chip is connected to a power supply.

5. A conductivity detection device according to claim 1, characterized in that: The compensation relationship is determined by fitting a plurality of groups of temperature signals, conductivity signals and first conductivity measured under a first medium with the same conductivity; the conductivity of the first medium is the first conductivity.

6. A conductivity detection device according to claim 3, characterized in that: The control module is used to determine the conductivity after temperature compensation according to the following formula: σ=f(x,y)=axy 2 +bxy+cx+dy 2 +ey+f: Wherein: σ is the conductivity after temperature compensation, x is the conductivity digital signal value corresponding to the conductivity signal collected by the probe pair; y is the actual temperature value corresponding to the temperature signal; a=a1·a2, b=a1·b2, c=a1·c2, d=a2·b1, e=b1·b2, f=b1·c2; V F is the reference voltage of the analog-to-digital converter inside the control module, N is the resolution of the analog-to-digital converter; L is the distance between the two probes of the probe pair, S is the cross-sectional area of ​​the space between the two probes; R5 is the resistance value of the first resistor, R6 is the resistance value of the second resistor, and R7 is the resistance value of the third resistor; V REF1 is the voltage value of the first reference voltage, V REF2 is the voltage value of the second reference voltage; a2, b2 and c2 are constant coefficients, which are obtained based on fitting processing of multiple groups of temperature signals, conductivity signals and first conductivity measured under the first medium with the same conductivity; the conductivity of the first medium is the first conductivity.

7. A conductivity detection method, characterized in that: For use in a conductivity detection device as described in any one of claims 1 to 6, the method comprises: collecting a conductivity signal and a temperature signal; based on a signal acquisition circuit, outputting the conductivity signal to the control module through operational amplification; according to the conductivity signal and the temperature signal, based on a compensation relationship, determining the conductivity after temperature compensation; the compensation relationship is the relationship between the conductivity signal, the temperature signal and the compensated conductivity.

8. A conductivity detection method according to claim 7, characterized in that: The compensation relationship is determined by a compensation formula, and the compensation formula includes a constant coefficient, and the constant coefficient is also determined by the following steps: collecting conductivity signals corresponding to the first medium at different temperatures to obtain n groups of correlation data between temperature and conductivity signals; determining the constant coefficient by dichotomy according to the first conductivity and the n groups of correlation data between temperature and conductivity signals; the conductivity of the first medium is the first conductivity, and n≥2 is a positive integer.

9. An ultrapure water circulation system, characterized in that: The ultrapure water circulation system comprises the conductivity detection device according to any one of claims 1 to 6.

10. An energy converter, characterized in that: The energy converter comprises the ultrapure water circulation system as claimed in claim 9.

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