A Conductivity Sensor Pressure Compensation Test System and Method

Abstract

The present application discloses a conductivity sensor pressure compensation test system and method, relating to the field of sensor testing. Among them, the conductivity sensor testing device includes a pressure-resistant housing, a temperature sensor, and an acquisition module; a standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value; a seawater thermostat is used to create a standard constant temperature environment for the conductivity sensor; a standard platinum resistance thermometer is placed in the seawater thermostat to measure the standard temperature value. During the test, the corresponding standard conductivity value can be calculated according to the standard pressure value, the standard temperature value, and the salinity value of the standard seawater recorded at each temperature control point; by fitting the conductivity measurement values, the standard conductivity values, and the standard pressure values corresponding to all temperature control points, the pressure compensation coefficient can be calculated. During measurement, using the pressure compensation coefficient to correct the conductivity measurement value of the conductivity sensor can improve the conductivity measurement accuracy.

Description

Technical Field

[0001] This application relates to the technical field of sensor testing, and particularly to a conductivity sensor pressure compensation test system and method. Background Art

[0002] Abyssal trenches with a depth of more than 6,500 meters have extremely rich and special scientific phenomena. Conducting abyssal scientific research is of great significance for revealing scientific issues such as the movement of the Earth's continental plates, the origin of life, and tsunami warning. Seawater temperature, salinity, and depth characterize the physical and electromagnetic properties of seawater and are the most basic observation elements in abyssal physical ocean research. Conducting research on the all-depth high-precision and rapid-response temperature, salinity, and depth (Conductivity Temperature and Depth, abbreviated as CTD) measurement technology for submersible platforms not only provides the necessary environmental information for the underwater maneuverability and safe operation of submersible platforms, but also the high-precision temperature, salinity, and density distribution information obtained in the all-depth operation area from the sea surface to 11,000 meters will provide key data for conducting research on the material exchange and biological characteristics of abyssal marginal waters and revealing scientific research such as deep-sea turbulent mixing and ocean interior circulation.

[0003] Since the seawater temperature and salinity are relatively stable at depths below 2,000 meters, the requirements for measurement accuracy are relatively high. Generally, the temperature and salinity indicators are required to be 0.002 °C and 0.005 PSU, and when converted to conductivity measurement, it should be less than 0.003 mS / cm. When using a conductivity sensor for large-depth high-precision CTD, the structural deformation caused by the change in the microstructure of the conductivity sensor material in a high-pressure environment cannot be ignored. However, there is no method for pressure compensation or correction of conductivity sensors in existing industry standards, resulting in inaccurate deep-sea conductivity measurement. Summary of the Invention

[0004] In view of this, this application provides a conductivity sensor pressure compensation test system and method to obtain a pressure compensation coefficient to correct the measured value of the conductivity sensor and improve the conductivity measurement accuracy.

[0005] To achieve the above object, this application provides the following solutions.

[0006] On the one hand, this application provides a conductivity sensor pressure compensation test system, including: a conductivity sensor test device, a host computer, a standard pressure gauge, a seawater constant temperature bath, a standard platinum resistance thermometer, and a temperature measuring bridge;

[0007] The conductivity sensor testing device includes a pressure-resistant housing, a temperature sensor, and an acquisition module; the pressure-resistant housing includes a pressure-resistant cylinder, a pressure-resistant flange, and a sealing cylinder; one side of the pressure-resistant flange is connected to the pressure-resistant cylinder, and the other side of the pressure-resistant flange is connected to the sealing cylinder; one end of the pressure-resistant cylinder is a pressure pipe interface with external threads for connecting the pressure pipe of a standard pressure gauge; the other end of the pressure-resistant cylinder has internal threads and is connected to one side of the pressure-resistant flange; both the temperature sensor and the conductivity sensor are located inside the pressure-resistant cylinder; the acquisition module is located inside the sealing cylinder; the temperature sensor and the conductivity sensor are installed on one side of the pressure-resistant flange, and the acquisition module is installed on the other side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are electrically connected to the acquisition module; the acquisition module is also communicatively connected to a host computer;

[0008] The standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value;

[0009] The seawater thermostat is used to create a standard constant temperature environment for the conductivity sensor;

[0010] The standard platinum resistance thermometer is placed in the seawater thermostat to measure the standard temperature value;

[0011] The temperature-measuring bridge is connected to the standard platinum resistance thermometer to read and display the standard temperature value measured by the standard platinum resistance thermometer.

[0012] Optionally, the temperature control fluctuation and uniformity of the seawater thermostat are better than 0.003°C.

[0013] Optionally, the accuracy of the temperature sensor is the same as that of the standard platinum resistance thermometer.

[0014] Optionally, the pressure-resistant housing is made of stainless steel or titanium.

[0015] On the other hand, the present application provides a method for testing the pressure compensation of a conductivity sensor, based on the conductivity sensor pressure compensation testing system; the method for testing the pressure compensation of a conductivity sensor includes:

[0016] During the test, after filling the conductivity sensor with standard seawater of known salinity and installing it in the pressure-resistant cylinder, place the conductivity sensor testing device in the seawater thermostat;

[0017] Combine the ocean temperature and salinity changes to select different temperature control points and pressure combinations, control the temperature through the seawater thermostat, and pressurize through the standard pressure gauge;

[0018] When the conductivity measurement value of the conductivity sensor does not monotonically change within a preset time and the indication value of the temperature sensor is consistent with the standard temperature value displayed by the temperature-measuring bridge, record the conductivity measurement value, the standard pressure value, and the standard temperature value of the current temperature control point, and then change the temperature and pressure values to conduct the next temperature control point test;

[0019] Calculate the corresponding standard conductivity value according to the standard pressure value, standard temperature value and salinity value of standard seawater recorded at each temperature control point;

[0020] Fit the conductivity measurement values, standard conductivity values and standard pressure values corresponding to all temperature control points to calculate the pressure compensation coefficient;

[0021] During measurement, use the pressure compensation coefficient to correct the conductivity measurement value of the conductivity sensor.

[0022] Optionally, filling the conductivity sensor with standard seawater of known salinity and installing the pressure-resistant cylinder specifically includes:

[0023] Fill the conductivity sensor with standard seawater of known salinity through a self-priming pump, then seal both ends of the conductivity sensor with stop clips and install it on the pressure-resistant flange;

[0024] After filling the pressure-resistant cylinder with clear water, put it on the pressure-resistant flange and tighten and reinforce it.

[0025] Optionally, the combining of different temperature control points and pressure combinations according to the changes of ocean temperature and salinity specifically includes:

[0026] Combine the changes of ocean temperature and salinity to select (20°C, 1 MPa), (9°C, 5 MPa), (4.5°C, 10 MPa), (2.5°C, 20 MPa), (2°C, 50 MPa) and (1.5°C, 70 MPa) as different temperature control points and pressure combinations.

[0027] Optionally, the preset time is 10 min.

[0028] Optionally, the fitting of the conductivity measurement values, standard conductivity values and standard pressure values corresponding to all temperature control points to calculate the pressure compensation coefficient specifically includes:

[0029] Based on the formula Fit the conductivity measurement values, standard conductivity values and standard pressure values corresponding to all temperature control points to calculate the pressure compensation coefficient ; where is the conductivity measurement value corresponding to the th temperature control point; is the standard conductivity value corresponding to the th temperature control point; is the standard pressure value corresponding to the th temperature control point.

[0030] Optionally, during measurement, using the pressure compensation coefficient to correct the conductivity measurement value of the conductivity sensor specifically includes:

[0031] During measurement, based on the formula The measured conductivity value of the conductivity sensor is corrected to obtain the corrected conductivity value and output; wherein is the corresponding measured pressure value

[0032] According to the specific embodiments provided in this application, the following technical effects are disclosed in this application:

[0033] In a conductivity sensor pressure compensation test system and method provided by this application, the conductivity sensor test device includes a pressure-resistant housing, a temperature sensor, and an acquisition module; a standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value; a seawater thermostat is used to create a standard constant temperature environment for the conductivity sensor; a standard platinum resistance thermometer is placed in the seawater thermostat to measure the standard temperature value. During the test, the corresponding standard conductivity value can be calculated based on the standard pressure value, standard temperature value, and salinity value of the standard seawater recorded at each temperature control point; by fitting the conductivity measurement values, standard conductivity values, and standard pressure values corresponding to all temperature control points, the pressure compensation coefficient can be calculated. During measurement, using the pressure compensation coefficient to correct the conductivity measurement value of the conductivity sensor can improve the measurement accuracy of conductivity, especially for deep-sea conductivity BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings

[0035] Figure 1 is a schematic structural diagram of a conductivity sensor pressure compensation test system

[0036] Figure 2 is a schematic structural diagram of a conductivity sensor test device

[0037] Figure 3 is a schematic diagram of filling standard seawater with a known salinity into the conductivity sensor

[0038] Figure 4 is a schematic diagram of the fitting curve of the conductivity measurement value, standard conductivity value, and standard pressure value in a certain embodiment DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0040] The purpose of the present application is to propose a conductivity sensor pressure compensation test system and method to obtain a pressure compensation coefficient to correct the measured value of the conductivity sensor and improve the accuracy of conductivity measurement.

[0041] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0042] As Figure 1 shown, in an exemplary embodiment, a conductivity sensor pressure compensation test system provided by the present application includes: a conductivity sensor test device 1, a host computer 2, a standard pressure gauge 3, a seawater thermostat 4, a standard platinum resistance thermometer 5, and a temperature measuring bridge 6.

[0043] As Figure 2 shown, in an exemplary embodiment, the conductivity sensor test device 1 includes a pressure-resistant housing, a temperature sensor 101, and a collection module 102. The pressure-resistant housing serves as a loading container for the conductivity sensor 100, temperature sensor 101, and collection module 102 to be tested. The specific structure includes a pressure-resistant cylinder 103, a pressure-resistant flange 104, and a sealing cylinder 105. In an exemplary embodiment, the conductivity sensor 100 to be tested can be a three-electrode conductivity sensor.

[0044] Among them, one side of the pressure-resistant flange 104 is connected to the pressure-resistant cylinder 103, and the other side of the pressure-resistant flange 104 is connected to the sealing cylinder 105. Specifically, one end of the pressure-resistant cylinder 103 is a pressure pipe interface 106 with an external thread for connecting the pressure pipe 301 of the standard pressure gauge 3. The other end of the pressure-resistant cylinder 103 has an internal thread and is connected to one side of the pressure-resistant flange 104. The temperature sensor 101 and the conductivity sensor 100 are both located inside the pressure-resistant cylinder 103. The collection module 102 is located inside the sealing cylinder 105. During the test, the inside of the pressure-resistant cylinder 103 is filled with standard seawater with a known salinity, and then the standard pressure gauge 3 is connected through the pressure pipe 301 for pressurization.

[0045] In an exemplary embodiment, the pressure-resistant housing can be in the shape of a cylindrical barrel and is made of stainless steel or titanium.

[0046] Specifically, the temperature sensor 101 and the conductivity sensor 100 are installed on one side of the pressure-resistant flange 104, and the acquisition module 102 is installed on the other side of the pressure-resistant flange 104. The temperature sensor 101 and the conductivity sensor 100 are electrically connected to the acquisition module 102. The acquisition module 102 is also communicatively connected to the host computer 2. The sealing cylinder 105 serves as a waterproof housing for the acquisition module 102, and is provided with a through hole for the cable to pass through. The connection between the cable and the sealing cylinder 105 needs to be sealed. The acquisition module 102 communicates with the host computer 2 via the cable. During the test, the acquisition module 102 simultaneously acquires the original signals of the conductivity sensor 100 and the temperature sensor 101, that is, the analog signals of the conductivity measurement value and the temperature measurement value, and converts them into digital signals and sends them to the host computer 2. In an exemplary embodiment, the acquisition module 102 can be screwed on the other side of the pressure-resistant flange 104, and the acquired conductivity measurement value and temperature measurement value are directly displayed in the host computer 2 in the form of digital signals.

[0047] During the test, the temperature sensor 101 and the conductivity sensor 100 are installed side by side and connected to the acquisition module 102, and the inside of the pressure-resistant cylinder 103 is filled with water. The temperature sensor 101 is used to measure the water temperature inside the pressure-resistant housing, and the temperature measurement value is sent to the host computer 2 via the acquisition module 102.

[0048] The standard pressure gauge 3 is used to pressurize the conductivity sensor 100 and record the standard pressure value. The standard pressure gauge 3 is located outside the seawater constant temperature bath 4 and is connected to the pressure pipe interface 106 of the conductivity sensor test device 1 through the pressure pipe 301, and then pressurized. The standard pressure value is the display value of the standard pressure gauge. The pressure pipe 301 can be made of stainless steel pipe.

[0049] The seawater constant temperature bath 4 is used to create a standard constant temperature environment for the conductivity sensor 100 to be tested. The style of the seawater constant temperature bath 4 is not specific, as long as the temperature control requirements are met. During the test, first place the conductivity sensor 100 into the conductivity sensor test device 1, and then immerse the entire conductivity sensor test device 1 in the standard seawater in the seawater constant temperature bath 4 for temperature equilibrium to make the temperature inside and outside the conductivity sensor test device 1 the same.

[0050] In an exemplary embodiment, the seawater constant temperature bath 4 can adopt a high-precision constant temperature bath, and its temperature control fluctuation and uniformity are better than 0.003 °C, preferably 0.001 °C, and more preferably 0.0005 °C.

[0051] The standard platinum resistance thermometer 5 is placed in the seawater constant temperature bath 4 and is used to measure the standard temperature value of the standard seawater in the seawater constant temperature bath 4.

[0052] The temperature-measuring bridge 6 is connected to the standard platinum resistance thermometer 5 and is used to read and display the standard temperature value measured by the standard platinum resistance thermometer 5 for the experimenter to record.

[0053] The temperature sensor 100 built into the conductivity sensor test device 1 is set for comparison with the standard platinum resistance thermometer 5 placed in the seawater thermostat 4 to monitor whether the temperatures inside and outside the pressure hull are consistent. Therefore, the temperature sensor 100 needs to have the same accuracy as the standard platinum resistance thermometer 5.

[0054] Based on Figure 1 the conductivity sensor pressure compensation test system shown, the present application also provides a conductivity sensor pressure compensation test method. The conductivity sensor pressure compensation test method includes the following steps S1 to S6.

[0055] S1: During the test, after filling the conductivity sensor 100 with standard seawater of known salinity and installing the pressure-resistant cylinder 103, place the conductivity sensor test device 1 in the seawater thermostat 4.

[0056] As Figure 3 shown, the standard seawater of known salinity can be filled into the conductivity sensor 100 through a self-priming pump, and then both ends of the conductivity sensor 100 are sealed with stop clips 107 and then installed on the pressure-resistant flange 104. Specifically, the conductivity sensor 100 is mechanically connected to the pressure-resistant flange 104 through a connecting seat, and there are wires inside the connecting seat. The wires pass through the through holes provided on the pressure-resistant flange 104 and are electrically connected to the acquisition module 102. Similarly, the wires of the temperature sensor 101 can also pass through the through holes provided on the pressure-resistant flange 104 and be electrically connected to the acquisition module 102. The connection between the wires and the pressure-resistant flange 104 needs to be sealed.

[0057] After filling the pressure-resistant cylinder 103 with clear water, slowly put the pressure-resistant cylinder 103 on the pressure-resistant flange 104 and tighten it for reinforcement. Then connect the pressure pipe interface 106 of the external thread of the pressure-resistant cylinder 103 to the standard pressure gauge 3 through the pressure pipe 301, and then place the entire conductivity sensor test device 1 into the seawater thermostat 4. The seawater thermostat 4 is also filled with standard seawater of known salinity.

[0058] S2: Select different temperature control points and pressure combinations according to the changes in ocean temperature and salinity, control the temperature through the seawater thermostat 4, and apply pressure through the standard pressure gauge 3.

[0059] By combining the changes in ocean temperature and salinity to select different temperature control points and pressure combinations, temperature control points and pressure combinations such as (20°C, 1 MPa), (9°C, 5 MPa), (4.5°C, 10 MPa), (2.5°C, 20 MPa), (2°C, 50 MPa), (1.5°C, 70 MPa), etc. can be referred to. Subsequently, temperature control and pressure application are carried out according to different temperature control points and pressure combinations.

[0060] Since the temperature inside the pressure-resistant shell will rise after pressure application and the internal pressure will drop after temperature control and heat dissipation, pressure can be applied in advance to 102% of the reference pressure value in the above temperature control points and pressure combinations for pressure holding.

[0061] S3: When the conductivity measurement value uploaded by the acquisition module 102 shown on the host computer 2 does not change monotonically within the preset time (usually 10 min) and the indication value of the temperature sensor is consistent with the indication value of the temperature measuring bridge, record the conductivity measurement value, standard pressure value, and standard temperature value of the current temperature control point, and then change the temperature and pressure values to conduct the next temperature control point test.

[0062] Among them, the indication value of the temperature sensor refers to the temperature measurement value of the temperature sensor 101. The indication value of the temperature measuring bridge refers to the standard temperature value displayed by the temperature measuring bridge 6. The salinity value of the standard seawater with a known salinity can also be called the standard salinity value. For the th temperature control point, record the corresponding conductivity measurement value, standard pressure value, and standard temperature value as , and .

[0063] S4: Calculate the corresponding standard conductivity value according to the standard pressure value, standard temperature value, and salinity value of the standard seawater recorded for each temperature control point.

[0064] Based on the standard pressure value , standard temperature value recorded for each temperature control point and the salinity value of the injected standard seawater, the standard conductivity value corresponding to each temperature control point can be calculated according to the PSS - 78 salinity standard formula.

[0065] S5: Fit the conductivity measurement values, standard conductivity values, and standard pressure values corresponding to all temperature control points to calculate the pressure compensation coefficient.

[0066] Refer to formulas (1) and (2) to fit the conductivity measurement values, standard conductivity values, and standard pressure values corresponding to all temperature control points to calculate the pressure compensation coefficient .

[0067] (1)

[0068] (2)

[0069] Wherein is the conductivity measurement value corresponding to the th temperature control point; is the standard conductivity value corresponding to the th temperature control point; is the standard pressure value corresponding to the th temperature control point.

[0070] During fitting, is used as the independent variable, and is used as the dependent variable. A linear function is used to fit all values and values. That is, during fitting, and are substituted for fitting. The slope value obtained from the fitting is the pressure compensation coefficient value, which is usually a fixed value.

[0071] S6: During measurement, the pressure compensation coefficient is used to correct the conductivity measurement value of the conductivity sensor 100.

[0072] During measurement, based on formula (3), the conductivity measurement value measured in real time by the conductivity sensor 100 is corrected to obtain the conductivity correction value as the measured output.

[0073] (3)

[0074] Wherein is the pressure measurement value corresponding to the current measurement. The measured conductivity value (i.e., the conductivity measurement value) is corrected by formula (3) to make the measurement more accurate in the deep sea.

[0075] In this application, by testing the pressurized conductivity sensor 100 in the seawater thermostat 4 and fitting the measured conductivity value and the standard conductivity value with the pressure value, the pressure compensation coefficient of the current conductivity sensor 100 can be obtained. During deep sea measurement, using this pressure compensation coefficient to correct the measured conductivity value of the conductivity sensor 100 can greatly improve the accuracy of deep sea conductivity measurement.

[0076] The following provides a specific embodiment of the conductivity sensor pressure compensation test system and method of this application.

[0077] Using the above method to test a certain type of three - electrode conductivity sensor, the test results are shown in Table 1 below.

[0078] Table 1 Measured conductivity values under different pressures

[0079]

[0080] Referring to formulas (1) and (2), taking each standard pressure value in Table 1 (corresponding to ) as the independent variable , the ratio of each measured conductivity value to the corresponding standard conductivity value is called the conductivity ratio. Taking each conductivity ratio - 1 (corresponding to ) as the dependent variable , using a linear function to fit all values and values. The fitted straight line is as shown in Figure 4 , that is, the fitted straight line is obtained. The slope value of the fit is the pressure compensation coefficient value, that is . When fitting, the trend line function of the excel chart can also be used to add the trend line formula, and the first - order term coefficient obtained is .

[0081] Based on formula (3), the measured conductivity values are corrected. The results after pressure and temperature compensation correction are shown in Table 2 below.

[0082] Table 2 Conductivity correction values under different pressures

[0083]

[0084] As a comparison, using the theoretical pressure compensation coefficient - 9.7E - 8 to correct the measured conductivity values, the results after pressure and temperature compensation correction are shown in Table 3 below.

[0085] Table 3 Conductivity correction values under different pressures when using the theoretical pressure compensation coefficient - 9.7E - 8

[0086]

[0087] Comparing the results in Table 2 and Table 3, it can be seen that when the pressure compensation coefficients do not match, the conductivity error (error after correction) will increase with the increase of pressure, exceeding the requirements for deep - sea conductivity measurement. However, using the pressure compensation coefficient calculated in this application to correct the measured conductivity values, the error after correction does not exceed 0.0001, which can meet the requirements for high - precision deep - sea conductivity measurement.

[0088] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0089] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present application.

Claims

1. A conductivity sensor pressure compensation test system, characterized in that: include: Conductivity sensor test device, host computer, standard pressure gauge, seawater constant temperature bath, standard platinum resistance thermometer and temperature measuring bridge; The conductivity sensor testing device comprises a pressure-resistant shell, a temperature sensor and a collection module; the pressure-resistant shell comprises a pressure-resistant cylinder, a pressure-resistant flange and a sealing cylinder; one side of the pressure-resistant flange is connected to the pressure-resistant cylinder, and the other side of the pressure-resistant flange is connected to the sealing cylinder; one end of the pressure-resistant cylinder is an externally threaded pressure pipe interface for connecting the pressure pipe of a standard pressure gauge; the other end of the pressure-resistant cylinder is an internally threaded interface connected to one side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are both located inside the pressure-resistant cylinder; the collection module is located inside the sealing cylinder; the temperature sensor and the conductivity sensor are installed on one side of the pressure-resistant flange, and the collection module is installed on the other side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are electrically connected to the collection module; the collection module is also connected to the host computer for communication; The standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value; The seawater constant temperature tank is used to create a standard constant temperature environment for the conductivity sensor; The standard platinum resistance thermometer is placed in a seawater constant temperature bath to measure the standard temperature value; The temperature measuring bridge is connected to a standard platinum resistance thermometer and is used to read and display the standard temperature value measured by the standard platinum resistance thermometer.

2. The conductivity sensor pressure compensation test system according to claim 1, characterized in that: The temperature control fluctuation and uniformity of the seawater constant temperature bath are better than 0.003°C.

3. The conductivity sensor pressure compensation test system according to claim 1, characterized in that: The temperature sensor has the same accuracy as a standard platinum resistance thermometer.

4. The conductivity sensor pressure compensation test system according to claim 1, characterized in that: The pressure-resistant shell is made of stainless steel or titanium.

5. A conductivity sensor pressure compensation test method, characterized in that: A conductivity sensor pressure compensation test system based on any one of claims 1 to 4; The conductivity sensor pressure compensation test method comprises: During the test, fill the conductivity sensor with standard seawater of known salinity and install the pressure-resistant cylinder, then place the conductivity sensor test device in a seawater constant temperature bath; Different temperature control points and pressure combinations are selected in combination with changes in ocean temperature and salinity. The temperature is controlled by a seawater constant temperature tank and the pressure is increased by a standard pressure gauge. When the conductivity measurement value of the conductivity sensor changes non-monotonically within the preset time and the temperature sensor indication is consistent with the standard temperature value displayed by the temperature measuring bridge, the conductivity measurement value, standard pressure value and standard temperature value of the current temperature control point are recorded, and then the temperature and pressure values ​​are changed to perform the next temperature control point test; Calculate the corresponding standard conductivity value according to the standard pressure value, standard temperature value and standard seawater salinity value recorded at each temperature control point; The conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points are fitted to calculate the pressure compensation coefficient; The conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points are fitted to calculate the pressure compensation coefficient, specifically including: Based on the formula Fit the conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points to calculate the pressure compensation coefficient ;in For the The conductivity measurement value corresponding to each temperature control point; For the The standard conductivity value corresponding to each temperature control point; For the The standard pressure value corresponding to each temperature control point; During measurement, the pressure compensation coefficient is used to correct the conductivity measurement value of the conductivity sensor.

6. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The method of filling the conductivity sensor with standard seawater of known salinity and installing a pressure-resistant cylinder specifically includes: Fill the conductivity sensor with standard seawater of known salinity through a self-priming pump, then seal both ends of the conductivity sensor with cut-off clamps and install it on a pressure-resistant flange; After filling the pressure-resistant cylinder with clean water, put it on the pressure-resistant flange and tighten it to reinforce it.

7. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The method of selecting different temperature control points and pressure combinations in combination with changes in ocean temperature and salinity specifically includes: In combination with changes in ocean temperature and salinity, (20℃, 1MPa), (9℃, 5MPa), (4.5℃, 10MPa), (2.5℃, 20MPa), (2℃, 50MPa) and (1.5℃, 70MPa) are selected as different temperature control points and pressure combinations.

8. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The preset time is 10 minutes.

9. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: During the measurement, the conductivity measurement value of the conductivity sensor is corrected using the pressure compensation coefficient, specifically including: When measuring, based on the formula Conductivity measurements for conductivity sensors Make corrections to obtain conductivity correction values Output is performed; is the corresponding pressure measurement value.

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