Optical dissolved oxygen sensor response time test device and test method

Abstract

The present invention belongs to the technical field of optical dissolved oxygen sensors, and specifically relates to an optical dissolved oxygen sensor response time test device and test method. The test device includes a circulation pool, a thermostatic bath, a host computer, a first storage tank for storing oxygen-free water, and a second storage tank for storing saturated dissolved oxygen water; the oxygen sensitive membrane of the optical dissolved oxygen sensor to be tested is located in the circulation pool, and the circulation pool, the first storage tank and the second storage tank are all placed in the thermostatic bath; a main pipe peristaltic pump is provided at the inflow end of the circulation pool; the first storage tank is connected to the circulation pool to form an oxygen-free water circulation loop, and the loop is provided with a first circulation valve; the second storage tank is connected to the circulation pool to form a saturated dissolved oxygen water circulation loop, and the loop is provided with a second circulation valve; the host computer is connected to a control module, and the control module is connected to the thermostatic bath, the main pipe peristaltic pump, the first circulation valve and the second circulation valve. The present invention can realize automatic testing of the response time of the optical dissolved oxygen sensor at different temperatures and different flow rates, and improves the accuracy of the test data.

Description

Technical Field

[0001] The invention belongs to the technical field of optical dissolved oxygen sensors, and in particular relates to a response time testing device and a testing method for an optical dissolved oxygen sensor. Background Art

[0002] Dissolved oxygen in seawater is closely related to a variety of marine biogeochemical processes. It is an important research topic in marine science and one of the important parameters for monitoring the marine ecological environment. Slight changes in dissolved oxygen in seawater will have a significant impact on the marine environment, especially on the marine nitrogen cycle and various redox processes. Therefore, accurate and continuous measurement of dissolved oxygen concentration in seawater is of great scientific significance. The optical dissolved oxygen sensor based on the principle of fluorescence quenching overcomes the shortcomings of traditional dissolved oxygen sensors and has the advantages of accurate and fast measurement, anti-interference, and no oxygen consumption during the measurement process. Therefore, the optical method based on the principle of fluorescence quenching is the most suitable technology for long-term in-situ detection of the ocean.

[0003] However, when measuring the dissolved oxygen concentration in water, the oxygen molecules in the water must diffuse into the oxygen sensitive membrane of the optical dissolved oxygen sensor, so that the oxygen partial pressure in the oxygen sensitive membrane reaches equilibrium with the oxygen partial pressure in the ambient medium. Only then can the output of the optical dissolved oxygen sensor represent the oxygen concentration of the measured water, which results in a longer response time for the optical dissolved oxygen sensor. When the optical dissolved oxygen sensor is used for continuous profile measurement (such as on Argo floats, gliders and other platforms), the slower response will have a lagging effect on the measurement results. In order to obtain more accurate profile dissolved oxygen concentration data, it is necessary to analyze the impact of the response time of the optical dissolved oxygen sensor on the measurement results.

[0004] The response time of an optical dissolved oxygen sensor refers to the time required for the dissolved oxygen concentration displayed by the sensor to rise to 63% (t63) or 90% (t90) of the theoretical value of saturated dissolved oxygen water concentration when the sensor is moved from oxygen-free water to saturated dissolved oxygen water. The current measurement method for the response time of an optical dissolved oxygen sensor is as follows:

[0005] The optical dissolved oxygen sensor to be tested is placed in two solutions (one is oxygen-free water prepared by adding anhydrous sodium sulfite reagent, and the other is saturated dissolved oxygen water) quickly and alternately, and the measured dissolved oxygen concentration value is recorded at the same time, and finally the response time of the optical dissolved oxygen sensor to be tested is obtained; however, the current measurement method has the following defects:

[0006] 1) Manual operation is required, which will have a subjective impact on the measurement data;

[0007] 2) When the optical dissolved oxygen sensor is placed alternately in the two solutions, it will inevitably be exposed to the air for a short time. The response speed of the optical dissolved oxygen sensor in the air is faster than that in the aqueous solution, which will cause errors in the measurement results.

[0008] 3) The data output by the optical dissolved oxygen sensor is discrete, so the response time t63 or t90 cannot be accurately given;

[0009] 4) It is impossible to study the effects of flow rate and temperature on the response time of the optical dissolved oxygen sensor; however, theoretical analysis shows that the factors affecting the response time of the optical dissolved oxygen sensor mainly depend on the flow rate and temperature of the fluid on the surface of the oxygen sensitive membrane. Summary of the invention

[0010] In view of the deficiencies existing in the related art, the present invention provides an optical dissolved oxygen sensor response time testing device and a testing method, aiming to realize automatic testing of the response time of the optical dissolved oxygen sensor under different temperatures and different flow rates, and improve the accuracy of the test data.

[0011] The optical dissolved oxygen sensor response time testing device of the present invention comprises:

[0012] The flow cell is a sealed container having an inflow end and an outflow end arranged opposite to each other. One end of the optical dissolved oxygen sensor to be measured is sealedly connected to the flow cell so that the oxygen sensitive membrane on the sensor is located in the flow cell, and the placement direction of the oxygen sensitive membrane is parallel to the flow direction of the flow cell; the inflow end of the flow cell is connected to an inflow main pipe, and a main pipe peristaltic pump is provided on the inflow main pipe;

[0013] The first storage tank is a sealed container for storing oxygen-free water; the first storage tank is connected to the inflow main pipe of the circulation pool through a first inflow pipe, and is connected to the outflow end of the circulation pool through a first outflow pipe, and the first inflow pipe and the first outflow pipe are both provided with a first circulation valve;

[0014] The second storage tank is a sealed container for storing saturated dissolved oxygen water; the second storage tank is connected to the inflow main pipe of the circulation pool through a second inflow pipe, and is connected to the outflow end of the circulation pool through a second outflow pipe; the second inflow pipe and the second outflow pipe are both provided with a second circulation valve;

[0015] A constant temperature bath, wherein the circulation pool, the first storage tank and the second storage tank are all placed in the constant temperature bath;

[0016] The upper computer is connected to a control module, and the control module is communicatively connected with the constant temperature bath, the main pipe peristaltic pump, the first flow valve, the second flow valve and the optical dissolved oxygen sensor to be measured.

[0017] The above technical scheme forms an oxygen-free water circulation loop and a saturated dissolved oxygen water circulation loop by setting and interconnecting the first storage tank, the second storage tank and the circulation pool; under the control of the host computer and its control module, the two circuits can be quickly switched by changing the switching states of the first circulation valve and the second circulation valve, thereby realizing automatic testing of the response time of the optical dissolved oxygen sensor, avoiding the subjective influence caused by manual operation under the current measurement method and the measurement error caused by short exposure to the air, thereby improving the accuracy of the test data; in addition, through the setting and regulation of the constant temperature bath and the main pipe peristaltic pump, quantitative testing and research on the response time of the optical dissolved oxygen sensor under different temperatures and different flow rates can be realized.

[0018] In some embodiments, the optical dissolved oxygen sensor response time test device also includes an oxygen-free water generation unit, which includes a first vacuum degassing device, a first peristaltic pump and a first regulating valve that are communicatively connected to the control module; the two ends of the first peristaltic pump are respectively connected to the first storage tank through a first suction pipe and a first inlet pipe, so as to pump out the solution in the first storage tank through the first suction pipe and then return it to the first storage tank through the first inlet pipe; the first vacuum degassing device is arranged on the first suction pipe, and the first regulating valve is arranged on the first inlet pipe; the first storage tank is installed with a first optical dissolved oxygen sensor that is communicatively connected to the control module, and is used to monitor the dissolved oxygen concentration of the solution in the first storage tank in real time. This technical solution can realize the automatic generation of oxygen-free water in the first storage tank through the arrangement of the first optical dissolved oxygen sensor and the oxygen-free water generation unit and the degassing treatment method.

[0019] In some of the embodiments, the optical dissolved oxygen sensor response time test device also includes a saturated dissolved oxygen water generating unit, which includes an electrolyte storage tank, an electrolytic cell, a second peristaltic pump and an electrolytic power supply which are communicatively connected to the control module; the electrolyte storage tank is used to store electrolyte and is connected to the second storage tank via a return pipe; the electrolytic cell is a closed container, and its top is connected to the second storage tank via a second inlet pipe; the two ends of the second peristaltic pump are respectively connected to the lower part of the electrolytic cell and the electrolyte storage tank to pump the electrolyte in the electrolyte storage tank into the electrolytic cell, and then the solution in the electrolytic cell flows into the second storage tank through the second inlet pipe; the electrolytic power supply is connected to the electrodes of the electrolytic cell to electrolyze the electrolyte in the electrolytic cell to generate an oxygen-containing solution; the return pipe and the second inlet pipe are both provided with a second regulating valve which is communicatively connected to the control module; a second optical dissolved oxygen sensor which is communicatively connected to the control module is installed in the second storage tank for real-time monitoring of the dissolved oxygen concentration of the solution in the second storage tank. This technical solution can realize the automatic generation of saturated dissolved oxygen water in the second storage tank by means of the provision of a second optical dissolved oxygen sensor and a saturated dissolved oxygen water generation unit and electrolysis.

[0020] In some of the embodiments, an ion membrane is provided in the electrolytic cell to separate the electrolytic cell into an anode chamber and a cathode chamber; the second peristaltic pump has a first channel and a second channel, the two ends of the first channel are respectively connected to the lower part of the anode chamber and the electrolyte storage tank, and the two ends of the second channel are respectively connected to the lower part of the cathode chamber and the electrolyte storage tank; the electrolytic power supply is connected to both the anode and the cathode of the electrolytic cell, so that oxygen is generated on the anode during electrolysis, and the oxygen is dissolved in the electrolyte in the anode chamber to generate an oxygen-containing solution; the second liquid inlet pipe is connected to the top of the anode chamber; the top of the cathode chamber is connected to the electrolyte storage tank through an overflow pipe. This technical solution, through the design of the anode chamber and the cathode chamber in the electrolytic cell, the provision of the second peristaltic pump with two channels, and the connection between the electrolytic power supply and the electrolytic cell, can realize the generation of oxygen-containing solution in the anode chamber, and then realize the generation of saturated dissolved oxygen water in the second storage tank.

[0021] In some embodiments, the first channel of the second peristaltic pump is connected to the electrolyte storage tank via a second pipette, and the second pipette is provided with a second vacuum degassing device; the second channel of the second peristaltic pump is connected to the electrolyte storage tank via a third pipette, and the third pipette is provided with a third vacuum degassing device. This technical solution degasses the electrolyte before entering the electrolytic cell by providing the second vacuum degassing device and the third vacuum degassing device.

[0022] In some of the embodiments, a high-precision flow meter is provided on the connecting pipeline between the first channel of the second peristaltic pump and the lower part of the anode chamber for measuring the flow rate of the electrolyte flowing into the anode chamber in real time.

[0023] In some embodiments, a stirring motor is installed in both the first storage tank and the second storage tank, and the stirring motor is in communication connection with the control module. The technical solution makes the dissolved oxygen concentration in each place in the first storage tank and the second storage tank uniform through the setting of the stirring motor.

[0024] The present invention also provides a test method for testing the response time of an optical dissolved oxygen sensor using the aforementioned optical dissolved oxygen sensor response time test device, comprising the following steps:

[0025] S1. Set the test temperature and test flow rate in the host computer;

[0026] S2, open the thermostatic bath to make it reach the test temperature and maintain the constant temperature;

[0027] S3, opening the two first circulation valves, and starting the main pipe peristaltic pump to pump the oxygen-free water in the first storage tank into the circulation pool, and at the same time regulating the flow rate of the main pipe peristaltic pump to reach the test flow rate and keep it stable;

[0028] S4, read the dissolved oxygen concentration reading of the optical dissolved oxygen sensor to be tested, and when it reaches 0% and stabilizes, close the two first circulation valves, and at the same time open the two second circulation valves, and the main pipe peristaltic pump pumps the saturated dissolved oxygen water in the second storage tank into the circulation pool;

[0029] S5. The host computer saves the data uploaded in real time by the optical dissolved oxygen sensor to be tested. When the dissolved oxygen concentration reading of the optical dissolved oxygen sensor to be tested exceeds 90%, data processing begins. The host computer automatically draws and fits the response time curve of the optical dissolved oxygen sensor to be tested, and then automatically obtains the response time t63 or t90 of the optical dissolved oxygen sensor to be tested under the test temperature and test flow rate.

[0030] S6, changing the test temperature, and executing steps S2 to S5 again;

[0031] S7, change the test flow rate, and execute steps S3 to S5 again.

[0032] The above technical scheme realizes the automatic test of the response time of the optical dissolved oxygen sensor at different temperatures and flow rates without manual intervention, avoiding the subjective influence caused by manual operation under the current measurement method and the measurement error caused by short exposure to the air, thereby improving the accuracy of the test data; and by automatically fitting the response time test curve, the response time t63 or t90 can be obtained more accurately, thereby providing a reliable basis for the response time compensation of the optical dissolved oxygen sensor.

[0033] In some embodiments, the test method further comprises a step of generating anaerobic water in the first storage tank; the step of generating anaerobic water specifically comprises:

[0034] Fill the first storage tank with NaOH solution;

[0035] Open the first regulating valve and the first peristaltic pump to continuously pump out the solution in the first storage tank, and return the solution to the first storage tank after being degassed by the first vacuum degassing device; repeat this cycle and adjust the flow rate of the first peristaltic pump until the dissolved oxygen concentration reading of the first optical dissolved oxygen sensor stably reaches 0%; close the first regulating valve and the first peristaltic pump.

[0036] In some embodiments, the test method further includes a step of generating saturated dissolved oxygen water in the second storage tank; the step of generating saturated dissolved oxygen water specifically includes:

[0037] Filling the second storage tank with NaOH solution; filling the electrolyte storage tank with NaOH solution;

[0038] Open the two second regulating valves and the second peristaltic pump to continuously pump the electrolyte in the electrolyte storage tank into the electrolytic cell; start the electrolytic power supply to electrolyze the electrolyte in the electrolytic cell to generate an oxygen-containing solution, the oxygen-containing solution continuously flows into the second storage tank through the second liquid inlet pipe, and the solution in the second storage tank flows back to the electrolyte storage tank through the liquid return pipe; repeat this cycle and adjust the current of the electrolytic power supply and the flow rate of the second peristaltic pump until the dissolved oxygen concentration reading of the second optical dissolved oxygen sensor stabilizes and reaches 100%; close the second peristaltic pump, the electrolytic power supply and the two second regulating valves.

[0039] Based on the above technical scheme, the optical dissolved oxygen sensor response time testing device and testing method in the embodiment of the present invention realize the full process automatic testing of the optical dissolved oxygen sensor response time, and improve the accuracy of the measurement data; realize the quantitative testing research of the optical dissolved oxygen sensor response time under different temperatures and different flow rates; can more accurately obtain the response time t63 or t90, thereby providing a reliable basis for the response time compensation of the optical dissolved oxygen sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0041] Figure 1 It is a structural principle diagram of the optical dissolved oxygen sensor response time testing device of the present invention;

[0042] Figure 2 The figure is a flow chart of the method for testing the response time of an optical dissolved oxygen sensor of the present invention.

[0043] In the figure:

[0044] 10. First storage tank; 11. First optical dissolved oxygen sensor; 12. First liquid pipette; 13. First vacuum degassing device; 14. First peristaltic pump; 15. First regulating valve; 16. First liquid inlet pipe;

[0045] 20. Second storage tank; 21. Second optical dissolved oxygen sensor; 22. Electrolyte storage tank; 23. Electrolytic cell; 231. Ion membrane; 232. Anode chamber; 233. Anode; 234. Cathode chamber; 235. Cathode; 24. Second peristaltic pump; 25. Second vacuum degassing device; 26. Third vacuum degassing device; 27. High-precision flow meter; 28. Electrolysis power supply; 29. ​​Second regulating valve; 30. Second liquid inlet pipe; 31. Overflow pipe; 32. Liquid return pipe; 33. Second liquid pipette; 34. Third liquid pipette;

[0046] 40. Circulation pool; 41. Optical dissolved oxygen sensor to be tested; 42. Main pipe peristaltic pump; 43. Inflow main pipe; 44. First inflow pipe; 45. First outflow pipe; 46. First circulation valve; 47. Second inflow pipe; 48. Second outflow pipe; 49. Second circulation valve; 50. Host computer; 51. Control module; 6. Stirring motor; 7. Watertight penetration parts; 8. Pressure-resistant joint. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", "front", "back", "vertical", "horizontal" and the like indicate positions or location relationships based on the attached Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0049] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "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 direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication 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.

[0051] like Figure 1 As shown, the optical dissolved oxygen sensor response time testing device of the present invention includes a circulation pool 40, a first storage tank 10, a second storage tank 20, a constant temperature bath and a host computer 50.

[0052] The circulation pool 40 is a sealed container having an inflow end and an outflow end arranged opposite to each other. The end of the optical dissolved oxygen sensor 41 to be tested close to the oxygen sensitive membrane is a test end, which is sealed and connected to the circulation pool 40 so that the oxygen sensitive membrane is located in the circulation pool 40, and the placement direction of the oxygen sensitive membrane is parallel to the circulation direction of the circulation pool 40; the other end of the optical dissolved oxygen sensor 41 to be tested is a non-test end, that is, an electrical connection end. The inflow end of the circulation pool 40 is connected to an inflow main pipe 43, and a main pipe peristaltic pump 42 is provided on the inflow main pipe 43; the main pipe peristaltic pump 42 is used to control the flow rate of the fluid in the circulation pool 40. Further, the shape of the circulation pool 40 is a tubular container along its circulation direction, and its diameter is slightly larger than the diameter of the inflow main pipe 43, so that the flow rate of the fluid after entering the circulation pool 40 through the inflow main pipe 43 is basically unchanged, that is, the flow rate of the main pipe peristaltic pump 42 is the flow rate of the fluid on the surface of the oxygen sensitive membrane. In addition, the test end of the optical dissolved oxygen sensor 41 to be tested has a temperature probe, which can read the temperature of the fluid in the flow cell 40 in real time, that is, the temperature of the fluid on the surface of the oxygen sensitive membrane.

[0053] The first storage tank 10 is a sealed container for storing oxygen-free water. The first storage tank 10 includes a first tank body, a first top cover and a sealing gasket located therebetween. The first storage tank 10 is connected to the inflow main pipe 43 of the circulation pool 40 via a first inflow pipe 44, and is connected to the outflow end of the circulation pool 40 via a first outflow pipe 45; the first inflow pipe 44 and the first outflow pipe 45 are both connected to the first top cover via a pressure-resistant joint 8. The oxygen-free water in the first storage tank 10 enters the circulation pool 40 via the first inflow pipe 44 and the inflow main pipe 43, and then returns to the first storage tank 10 via the first outflow pipe 45, thereby forming an oxygen-free water circulation loop. The first inflow pipe 44 and the first outflow pipe 45 are both provided with a first circulation valve 46, and the on-off of the oxygen-free water circulation loop is controlled by the switch of the first circulation valve 46.

[0054] The second storage tank 20 is a sealed container for storing saturated dissolved oxygen water. The second storage tank 20 includes a second tank body, a second top cover and a sealing gasket located therebetween. The second storage tank 20 is connected to the inflow main pipe 43 of the circulation pool 40 via a second inflow pipe 47, and is connected to the outflow end of the circulation pool 40 via a second outflow pipe 48; the second inflow pipe 47 and the second outflow pipe 48 are both connected to the second top cover via a pressure-resistant joint 8. The saturated dissolved oxygen water in the second storage tank 20 enters the circulation pool 40 via the second inflow pipe 47 and the inflow main pipe 43, and then returns to the second storage tank 20 via the second outflow pipe 48, thereby forming a saturated dissolved oxygen water circulation loop. The second inflow pipe 47 and the second outflow pipe 48 are both provided with a second circulation valve 49, and the on-off of the saturated dissolved oxygen water circulation loop is controlled by the switch of the second circulation valve 49.

[0055] The circulation pool 40, the first storage tank 10 and the second storage tank 20 are all placed in a thermostatic bath, and the pipes not placed in the thermostatic bath are wrapped with heat-insulating materials. By controlling the temperature of the thermostatic bath, the temperature of the circulation pool 40, the first storage tank 10 and the second storage tank 20 can be controlled. In theory, the temperature of the thermostatic bath is the temperature of the fluid on the surface of the oxygen sensitive membrane of the optical dissolved oxygen sensor 41 to be measured.

[0056] The host computer 50 is connected to a control module 51, and the control module 51 is communicated with the constant temperature bath and the main pipe peristaltic pump 42 to control the temperature of the constant temperature bath and the flow rate of the main pipe peristaltic pump; the control module 51 is also communicated with the first circulation valve 46 and the second circulation valve 49 to adjust the switching state of the first circulation valve 46 and the second circulation valve 49 to achieve rapid switching between the oxygen-free water circulation loop and the saturated dissolved oxygen water circulation loop; the control module 51 is also communicated with the optical dissolved oxygen sensor 41 to be tested to read the measurement data of the optical dissolved oxygen sensor 41 to be tested in real time.

[0057] In the above-mentioned exemplary embodiment, an oxygen-free water circulation loop and a saturated dissolved oxygen water circulation loop are formed by setting and interconnecting the first storage tank 10, the second storage tank 20 and the circulation pool 40; under the control of the host computer 50 and its control module 51, the two circuits can be quickly switched by changing the switch states of the first circulation valve 46 and the second circulation valve 49, that is, the instantaneous conversion of the fluid in the circulation pool 40 is achieved, so that the automatic test of the response time of the optical dissolved oxygen sensor 41 to be tested in the circulation pool 40 can be achieved, avoiding the subjective influence caused by manual operation under the current measurement method and the measurement error caused by short exposure to the air, thereby improving the accuracy of the test data; in addition, through the setting and regulation of the constant temperature bath and the main pipe peristaltic pump 42, the quantitative test study of the response time of the optical dissolved oxygen sensor at different temperatures and different flow rates can be achieved, and then the flow rate dependence of the response time at a constant temperature and the temperature dependence of the response time at a constant flow rate can be studied.

[0058] like Figure 1As shown, in some embodiments, the optical dissolved oxygen sensor response time test device also includes an oxygen-free water generation unit. The oxygen-free water generation unit includes a first vacuum degassing device 13, a first regulating valve 15, and a first peristaltic pump 14 that is communicatively connected to the control module 51. The two ends of the first peristaltic pump 14 are respectively connected to the first storage tank 10 through a first suction pipe 12 and a first inlet pipe 16, so as to pump out the solution in the first storage tank 10 through the first suction pipe 12, and then return to the first storage tank 10 through the first inlet pipe 16; the first suction pipe 12 and the first inlet pipe 16 are both connected to the first top cover through a pressure-resistant joint 8. The first vacuum degassing device 13 is arranged on the first suction pipe 12; the first regulating valve 15 is arranged on the first inlet pipe 16. The solution in the first storage tank 10 is pumped out through the first suction pipe 12 under the action of the first peristaltic pump 14, and after being degassed by the first vacuum degassing device 13, it returns to the first storage tank 10 through the first inlet pipe 16, thereby forming a circulation loop for the generation of oxygen-free water. The control module 51 is in communication connection with the first regulating valve 15 to control the on-off of the oxygen-free water generation circulation loop.

[0059] The first storage tank 10 is equipped with a first optical dissolved oxygen sensor 11 which is in communication with the control module 51 and is used to monitor the dissolved oxygen concentration of the solution in the first storage tank 10 in real time. It is understandable that the first optical dissolved oxygen sensor 11 is immersed in the solution in the first storage tank 10, and its electrical connection end is connected to the outside through the watertight penetration member 7. The upper computer 50 reads the dissolved oxygen concentration of the solution in the first storage tank 10 in real time through the control module 51, and adjusts the flow rate of the first peristaltic pump 14 accordingly; when the first optical dissolved oxygen sensor 11 detects that the dissolved oxygen concentration of the solution in the first storage tank 10 stably reaches 0%, it indicates that the generation of oxygen-free water in the first storage tank 10 is completed.

[0060] In the above exemplary embodiment, the automatic generation of oxygen-free water in the first storage tank 10 can be achieved through the provision of the first optical dissolved oxygen sensor 11 and the oxygen-free water generation unit and the degassing treatment.

[0061] like Figure 1As shown, in some embodiments, the optical dissolved oxygen sensor response time test device also includes a saturated dissolved oxygen water generating unit. The saturated dissolved oxygen water generating unit includes an electrolyte storage tank 22, an electrolytic cell 23, a second peristaltic pump 24 and an electrolytic power supply 28 that are communicatively connected to the control module 51. The electrolyte storage tank 22 is used to store electrolyte, and the electrolyte is a NaOH solution, and its concentration can be 0.02 mol / L; it should be noted that since the optical dissolved oxygen sensor is not sensitive to low-concentration NaOH solution, the use of low-concentration NaOH solution as the electrolyte will not affect the output of the optical dissolved oxygen sensor. The electrolyte storage tank 22 is connected to the second storage tank 20 through a return pipe 32; the electrolytic cell 23 is a closed container, and its top is connected to the second storage tank 20 through a second inlet pipe 30; the electrolytic cell 23 is placed in a constant temperature bath. The return pipe 32 and the second inlet pipe 30 are both connected to the second top cover through a pressure-resistant joint 8, and the return pipe 32 and the second inlet pipe 30 are both provided with a second regulating valve 29. The two ends of the second peristaltic pump 24 are respectively connected to the lower part of the electrolytic cell 23 and the electrolyte storage tank 22 to pump the electrolyte in the electrolyte storage tank 22 into the electrolytic cell 23, and then the solution in the electrolytic cell 23 flows into the second storage tank 20 through the second liquid inlet pipe 30. The electrolytic power supply 28 is connected to the electrodes of the electrolytic cell 23 to electrolyze the electrolyte in the electrolytic cell 23 to generate an oxygen-containing solution, and the oxygen-containing solution flows into the second storage tank 20 through the second liquid inlet pipe 30; the solution in the second storage tank 20 flows back to the electrolyte storage tank 22 through the return pipe 32; thereby forming a circulation loop for generating saturated dissolved oxygen water. The control module 51 is connected to the second regulating valve 29 in communication to control the on-off of the saturated dissolved oxygen water generation circulation loop.

[0062] A second optical dissolved oxygen sensor 21 is installed in the second storage tank 20 and is connected to the control module 51 for real-time monitoring of the dissolved oxygen concentration of the solution in the second storage tank 20. It is understandable that the second optical dissolved oxygen sensor 21 is immersed in the solution in the second storage tank 20, and its electrical connection end is connected to the outside through the watertight penetration member 7. The upper computer 50 reads the dissolved oxygen concentration of the solution in the second storage tank 20 in real time through the control module 51, and adjusts the flow rate of the second peristaltic pump 24 and the current of the electrolysis power supply 28 accordingly; when the second optical dissolved oxygen sensor 21 detects that the dissolved oxygen concentration of the solution in the second storage tank 20 stably reaches 100%, it indicates that the generation of saturated dissolved oxygen water in the second storage tank 20 is completed.

[0063] In the above exemplary embodiment, the automatic generation of saturated dissolved oxygen water in the second storage tank 20 can be achieved through the provision of the second optical dissolved oxygen sensor 21 and the saturated dissolved oxygen water generating unit and the electrolysis method.

[0064] like Figure 1As shown, in some embodiments, an ion membrane 231 is provided in the electrolytic cell 23 to separate the electrolytic cell 23 into an anode chamber 232 and a cathode chamber 234. The second peristaltic pump 24 is a dual-channel peristaltic pump, which has a first channel and a second channel; the two ends of the first channel are respectively connected to the lower part of the anode chamber 232 and the electrolyte storage tank 22, and the two ends of the second channel are respectively connected to the lower part of the cathode chamber 234 and the electrolyte storage tank 22, so as to pump the electrolyte in the electrolyte storage tank 22 into the anode chamber 232 and the cathode chamber 234 respectively. The electrolysis power supply 28 is connected to both the anode 233 and the cathode 235 of the electrolytic cell 23, so that oxygen is generated on the anode 233 of the electrolytic cell 23 during electrolysis, and the oxygen is dissolved in the electrolyte in the anode chamber 232 to generate an oxygen-containing solution. By controlling the current of the electrolysis power supply 28, the amount of oxygen generated by electrolysis can be controlled; by controlling the flow rate of the second peristaltic pump 24, the electrolyte flow rate can be kept uniform and the oxygen generated by electrolysis can be completely dissolved by the electrolyte near the electrode; thereby achieving control of the dissolved oxygen concentration. The second liquid inlet pipe 30 is connected to the top of the anode chamber 232 so that the oxygen-containing solution in the anode chamber 232 flows into the second storage tank 20. The top of the cathode chamber 234 is connected to the electrolyte storage tank 22 through an overflow pipe 31 so that the liquid in the cathode chamber 234 overflows into the electrolyte storage tank 22. The second liquid inlet pipe 30 and the overflow pipe 31 are both connected to the top cover of the electrolytic cell 23 through a pressure-resistant joint 8.

[0065] The above-mentioned schematic embodiment, through the design of the anode chamber 232 and the cathode chamber 234 in the electrolytic cell 23, the provision of the second peristaltic pump 24 with a dual channel, and the connection between the electrolytic power supply 28 and the electrolytic cell 23, can realize the generation of oxygen-containing solution in the anode chamber 232, and then realize the generation of saturated dissolved oxygen water in the second storage tank 20.

[0066] like Figure 1 As shown, in some embodiments, the first channel of the second peristaltic pump 24 is connected to the electrolyte storage tank 22 via a second pipette 33, and a second vacuum degassing device 25 is provided on the second pipette 33; the second channel of the second peristaltic pump 24 is connected to the electrolyte storage tank 22 via a third pipette 34, and a third vacuum degassing device 26 is provided on the third pipette 34. In this exemplary embodiment, the electrolyte before entering the electrolytic cell 23 is degassed by the arrangement of the second vacuum degassing device 25 and the third vacuum degassing device 26, so that the dissolved oxygen concentration of the oxygen-containing solution in the anode chamber 232 of the electrolytic cell 23 after electrolysis is only affected by the current of the electrolytic power supply 28 and the flow rate of the second peristaltic pump 24; thus, by accurately controlling the current of the electrolytic power supply 28 and the flow rate of the second peristaltic pump 24, a solution with a controllable variable dissolved oxygen concentration can be obtained in real time.

[0067] like Figure 1As shown, in some embodiments, a high-precision flow meter 27 is provided on the connecting pipeline between the first channel of the second peristaltic pump 24 and the lower part of the anode chamber 232 for measuring the flow rate of the electrolyte flowing into the anode chamber 232 in real time.

[0068] like Figure 1 As shown, in some embodiments, a stirring motor 6 is installed in both the first storage tank 10 and the second storage tank 20, and the stirring motor 6 is communicatively connected with the control module 51; through the setting of the stirring motor 6, the dissolved oxygen concentrations at various locations in the first storage tank 10 and the second storage tank 20 are made uniform.

[0069] The present invention also provides a test method for testing the response time of an optical dissolved oxygen sensor using the aforementioned optical dissolved oxygen sensor response time test device, comprising the following steps:

[0070] S1, setting the test temperature and test flow rate in the host computer 50;

[0071] S2, open the thermostatic bath to make it reach the test temperature and maintain the constant temperature;

[0072] S3, opening the two first circulation valves 46, and opening the main pipe peristaltic pump 42 to pump the oxygen-free water in the first storage tank 10 into the circulation pool 40, and at the same time regulating the flow rate of the main pipe peristaltic pump 42 to reach the test flow rate and keep it stable;

[0073] S4, read the dissolved oxygen concentration reading of the optical dissolved oxygen sensor 41 to be tested, and when it reaches 0% and stabilizes, close the two first circulation valves 46, and at the same time open the two second circulation valves 49, and the main pipe peristaltic pump 42 pumps the saturated dissolved oxygen water in the second storage tank 20 into the circulation pool 40, realizing the instantaneous conversion of the fluid in the circulation pool 40;

[0074] S5, the host computer 50 saves the data uploaded in real time by the optical dissolved oxygen sensor 41 to be tested, and starts data processing when the dissolved oxygen concentration reading of the optical dissolved oxygen sensor 41 to be tested exceeds 90%; the host computer 50 automatically draws and fits the response time curve of the optical dissolved oxygen sensor 41 to be tested, and then automatically obtains the response time t63 or t90 of the optical dissolved oxygen sensor 41 to be tested under the test temperature and test flow rate;

[0075] S6, changing the test temperature, and executing steps S2 to S5 again;

[0076] S7, change the test flow rate, and execute steps S3 to S5 again.

[0077] The above-mentioned illustrative embodiment realizes the automatic test of the response time of the optical dissolved oxygen sensor at different temperatures and different flow rates without manual intervention, thereby avoiding the subjective influence caused by manual operation under the current measurement method and the measurement error caused by short-term exposure to the air, and improving the accuracy of the test data; moreover, through the automatic fitting of the response time test curve of the optical dissolved oxygen sensor, the response time t63 or t90 can be obtained more accurately, avoiding the problem that the discrete output results of the optical dissolved oxygen sensor under the current measurement method cannot accurately give the response time t63 or t90, thereby providing a reliable basis for the response time compensation of the optical dissolved oxygen sensor.

[0078] In some embodiments, the test method further includes a step of generating anaerobic water in the first storage tank 10; the step of generating anaerobic water specifically includes:

[0079] Fill the first storage tank 10 with NaOH solution;

[0080] The first regulating valve 15 is opened, and the first peristaltic pump 14 is opened to continuously pump out the solution in the first storage tank 10, and the solution is returned to the first storage tank 10 after being degassed by the first vacuum degassing device 13; this cycle is repeated, and the flow rate of the first peristaltic pump 14 is adjusted until the dissolved oxygen concentration reading of the first optical dissolved oxygen sensor 11 stably reaches 0%; the first regulating valve 15 and the first peristaltic pump 14 are closed.

[0081] In some embodiments, the test method further includes a step of generating saturated dissolved oxygen water in the second storage tank 20; the step of generating saturated dissolved oxygen water specifically includes:

[0082] Fill the second storage tank 20 with NaOH solution; fill the electrolyte storage tank 22 with NaOH solution;

[0083] The two second regulating valves 29 are opened, and the second peristaltic pump 24 is opened to continuously pump the electrolyte in the electrolyte storage tank 22 into the electrolytic cell 23; the electrolytic power supply 28 is started to electrolyze the electrolyte in the electrolytic cell 23 to generate an oxygen-containing solution, and the oxygen-containing solution continuously flows into the second storage tank 20 through the second liquid inlet pipe 30, and the solution in the second storage tank 20 flows back to the electrolyte storage tank 22 through the liquid return pipe 32; this cycle is repeated, and the current of the electrolytic power supply 28 and the flow rate of the second peristaltic pump 24 are adjusted until the dissolved oxygen concentration reading of the second optical dissolved oxygen sensor 21 stably reaches 100%; the second peristaltic pump 24, the electrolytic power supply 28 and the two second regulating valves 29 are closed.

[0084] Combine the following Figure 1-Figure 2 , briefly describe the main process steps of the optical dissolved oxygen sensor response time test method of the present invention:

[0085] a) setting the test temperature and test flow rate in the host computer 50;

[0086] b) Open the thermostatic bath to make it reach the test temperature and maintain the constant temperature;

[0087] c) opening the first regulating valve 15 and the first peristaltic pump 14, so that the dissolved oxygen concentration of the solution in the first storage tank 10 is stably 0%, if not, adjusting the flow rate of the first peristaltic pump 14; opening the second peristaltic pump 24, the electrolysis power supply 28 and the two second regulating valves 29, so that the dissolved oxygen concentration of the solution in the second storage tank 20 is stably 100%, if not, adjusting the current of the electrolysis power supply 28 and the flow rate of the second peristaltic pump 24;

[0088] d) closing the first regulating valve 15 and the first peristaltic pump 14, and closing the second peristaltic pump 24, the electrolysis power supply 28 and the two second regulating valves 29;

[0089] e) opening the two first flow valves 46, starting the main pipe peristaltic pump 42, and regulating the flow rate of the main pipe peristaltic pump 42 to reach the test flow rate and keep it stable;

[0090] f) reading the dissolved oxygen concentration of the optical dissolved oxygen sensor 41 to be tested, and when it reaches 0% and stabilizes, closing the two first flow valves 46 and at the same time opening the two second flow valves 49;

[0091] g) The host computer 50 stores the data uploaded in real time by the optical dissolved oxygen sensor 41 to be tested, and starts data processing when the dissolved oxygen concentration reading of the optical dissolved oxygen sensor 41 to be tested exceeds 90%;

[0092] h) The host computer 50 automatically draws and fits the response time curve of the optical dissolved oxygen sensor 41 to be tested, and then automatically obtains the response time t63 or t90 of the optical dissolved oxygen sensor 41 to be tested under the test temperature and test flow rate;

[0093] i) changing the test temperature and performing steps b to h again;

[0094] j) Change the test flow rate and perform steps c to h again.

[0095] Through the description of multiple embodiments of the optical dissolved oxygen sensor response time test device and test method of the present invention, it can be seen that the present invention has at least one or more of the following advantages:

[0096] 1. The full process automatic test of the response time of the optical dissolved oxygen sensor is realized, which improves the accuracy of the test data;

[0097] 2. The quantitative test research on the response time of the optical dissolved oxygen sensor at different temperatures and flow rates was realized, and then the research on the flow rate dependence of the response time at constant temperature and the temperature dependence of the response time at constant flow rate were realized;

[0098] 3. The response time t63 or t90 of the optical dissolved oxygen sensor can be obtained more accurately, thereby providing a reliable basis for the response time compensation of the optical dissolved oxygen sensor.

[0099] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0100] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. Optical dissolved oxygen sensor response time test device, characterized in that: include: The circulation pool is a sealed container having an inflow end and an outflow end arranged opposite to each other. One end of the optical dissolved oxygen sensor to be measured is sealedly connected to the circulation pool so that the oxygen sensitive membrane on the sensor is located in the circulation pool, and the placement direction of the oxygen sensitive membrane is parallel to the flow direction of the circulation pool; the inflow end of the circulation pool is connected to an inflow main pipe, and the inflow main pipe is provided with a main pipe peristaltic pump; The first storage tank is a sealed container for storing oxygen-free water; the first storage tank is connected to the inflow main pipe of the circulation pool through a first inflow pipe, and is connected to the outflow end of the circulation pool through a first outflow pipe, and the first inflow pipe and the first outflow pipe are both provided with a first circulation valve; The second storage tank is a sealed container for storing saturated dissolved oxygen water; the second storage tank is connected to the inflow main pipe of the circulation pool through a second inflow pipe, and is connected to the outflow end of the circulation pool through a second outflow pipe; the second inflow pipe and the second outflow pipe are both provided with a second circulation valve; A constant temperature bath, wherein the circulation pool, the first storage tank and the second storage tank are all placed in the constant temperature bath; The host computer is connected to a control module, and the control module is communicatively connected with the constant temperature bath, the main pipe peristaltic pump, the first flow valve, the second flow valve and the optical dissolved oxygen sensor to be measured.

2. The optical dissolved oxygen sensor response time testing device according to claim 1, characterized in that: The optical dissolved oxygen sensor response time testing device also includes an oxygen-free water generating unit, which includes a first vacuum degassing device, a first peristaltic pump and a first regulating valve which are communicatively connected to the control module; two ends of the first peristaltic pump are respectively connected to the first storage tank via a first suction pipe and a first liquid inlet pipe, so as to pump out the solution in the first storage tank via the first suction pipe and then return the solution to the first storage tank via the first liquid inlet pipe; the first vacuum degassing device is arranged on the first suction pipe, and the first regulating valve is arranged on the first liquid inlet pipe; a first optical dissolved oxygen sensor which is communicatively connected to the control module is installed in the first storage tank, and is used for real-time monitoring of the dissolved oxygen concentration of the solution in the first storage tank.

3. The optical dissolved oxygen sensor response time testing device according to claim 2, characterized in that: The optical dissolved oxygen sensor response time test device also includes a saturated dissolved oxygen water generating unit, which includes an electrolyte storage tank, an electrolytic cell, a second peristaltic pump communicatively connected to the control module, and an electrolysis power supply; the electrolyte storage tank is used to store electrolyte, and is connected to the second storage tank via a return pipe; the electrolytic cell is a closed container, and its top is connected to the second storage tank via a second liquid inlet pipe; two ends of the second peristaltic pump are respectively connected to the lower part of the electrolytic cell and the electrolyte storage tank, so as to pump the electrolyte in the electrolyte storage tank into the electrolytic cell, and then make the solution in the electrolytic cell flow into the second storage tank through the second liquid inlet pipe; The electrolysis power supply is connected to the electrodes of the electrolytic cell to electrolyze the electrolyte in the electrolytic cell to generate an oxygen-containing solution; the return pipe and the second liquid inlet pipe are both provided with a second regulating valve that is communicatively connected to the control module; the second storage tank is installed with a second optical dissolved oxygen sensor that is communicatively connected to the control module, which is used to monitor the dissolved oxygen concentration of the solution in the second storage tank in real time.

4. The optical dissolved oxygen sensor response time testing device according to claim 3, characterized in that: An ion membrane is provided in the electrolytic cell to separate the electrolytic cell into an anode chamber and a cathode chamber; the second peristaltic pump has a first channel and a second channel, the two ends of the first channel are respectively connected to the lower part of the anode chamber and the electrolyte storage tank, and the two ends of the second channel are respectively connected to the lower part of the cathode chamber and the electrolyte storage tank; the electrolysis power supply is connected to both the anode and the cathode of the electrolytic cell to generate oxygen on the anode during electrolysis, and the oxygen is dissolved in the electrolyte of the anode chamber to generate an oxygen-containing solution; The second liquid inlet pipe is connected to the top of the anode chamber; The top of the cathode chamber is connected to the electrolyte storage tank via an overflow pipe.

5. The optical dissolved oxygen sensor response time testing device according to claim 4, characterized in that: The first channel of the second peristaltic pump is connected to the electrolyte storage tank via a second pipette, and the second pipette is provided with a second vacuum degassing device; the second channel of the second peristaltic pump is connected to the electrolyte storage tank via a third pipette, and the third pipette is provided with a third vacuum degassing device.

6. The optical dissolved oxygen sensor response time testing device according to claim 5, characterized in that: A high-precision flow meter is provided on the connecting pipeline between the first channel of the second peristaltic pump and the lower part of the anode chamber, for measuring the flow rate of the electrolyte flowing into the anode chamber in real time.

7. The optical dissolved oxygen sensor response time testing device according to claim 2 or 3, characterized in that: A stirring motor is installed in each of the first storage tank and the second storage tank, and the stirring motor is communicatively connected with the control module.

8. A method for testing the response time of an optical dissolved oxygen sensor to be tested using the optical dissolved oxygen sensor response time testing device as described in any one of claims 3 to 6, characterized in that: The steps include: S1, setting the test temperature and test flow rate in the host computer; S2, turning on the thermostatic bath to make it reach the test temperature and maintain the constant temperature; S3, opening the two first circulation valves, and opening the main pipe peristaltic pump to pump the oxygen-free water in the first storage tank into the circulation pool, and at the same time regulating the flow rate of the main pipe peristaltic pump to reach the test flow rate and keep it stable; S4, reading the dissolved oxygen concentration of the optical dissolved oxygen sensor to be tested, and when it reaches 0% and stabilizes, closing the two first circulation valves, and at the same time opening the two second circulation valves, and the main pipe peristaltic pump pumps the saturated dissolved oxygen water in the second storage tank into the circulation pool; S5, the host computer saves the data uploaded in real time by the optical dissolved oxygen sensor to be tested, and starts data processing when the dissolved oxygen concentration reading of the optical dissolved oxygen sensor to be tested exceeds 90%; the host computer automatically draws and fits the response time curve of the optical dissolved oxygen sensor to be tested, and then automatically obtains the response time t63 or t90 of the optical dissolved oxygen sensor to be tested under the test temperature and the test flow rate; S6, changing the test temperature, and executing steps S2 to S5 again; S7, changing the test flow rate, and executing steps S3 to S5 again.

9. A method for testing the response time of an optical dissolved oxygen sensor to be tested using the optical dissolved oxygen sensor response time testing device as claimed in claim 8, characterized in that: The step of generating oxygen-free water in the first storage tank is also included; the step of generating oxygen-free water specifically includes: Filling the first storage tank with NaOH solution; The first regulating valve is opened, and the first peristaltic pump is opened to continuously pump out the solution in the first storage tank, and the solution is returned to the first storage tank after being degassed by the first vacuum degassing device; this cycle is repeated, and the flow rate of the first peristaltic pump is adjusted until the dissolved oxygen concentration reading of the first optical dissolved oxygen sensor stably reaches 0%; the first regulating valve and the first peristaltic pump are closed.

10. A method for testing the response time of an optical dissolved oxygen sensor to be tested using the optical dissolved oxygen sensor response time testing device as claimed in claim 8, characterized in that: The invention also includes a step of generating saturated dissolved oxygen water in the second storage tank; the step of generating saturated dissolved oxygen water specifically includes: Filling the second storage tank with NaOH solution; filling the electrolyte storage tank with NaOH solution; Open the two second regulating valves, and start the second peristaltic pump to continuously pump the electrolyte in the electrolyte storage tank into the electrolytic cell; start the electrolytic power supply to electrolyze the electrolyte in the electrolytic cell to generate an oxygen-containing solution, the oxygen-containing solution continuously flows into the second storage tank through the second liquid inlet pipe, and the solution in the second storage tank flows back to the electrolyte storage tank through the return pipe; repeat this cycle, and adjust the current of the electrolytic power supply and the flow rate of the second peristaltic pump until the dissolved oxygen concentration reading of the second optical dissolved oxygen sensor stabilizes and reaches 100%; close the second peristaltic pump, the electrolytic power supply and the two second regulating valves.

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