CN117451961A - Seawater carbon dioxide measuring instrument calibration system and calibration method thereof - Google Patents

Abstract

The invention belongs to the field of carbon dioxide detectors. Specifically, it is a calibration method for a seawater carbon dioxide measuring instrument calibration system, which includes the following steps: S1 inputs a variety of standard gases with different carbon dioxide partial pressure value gradients, and checks the standard detector multiple times. Calibration; After S2 completes the calibration of the standard detector, calibrate the balancer component; S3 calibration work begins, open the waterway, observe and compare the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time, and obtain the compared data to complete the calibration of the underwater in-situ carbon dioxide measuring instrument; S4 records and processes the compared data to obtain the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument. This invention ensures that each component in the system is accurate before calibration, can minimize the interference of the external environment, and then opens the waterway, observes and compares the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time, and achieves high accuracy Testing and calibration.

Description

Calibration system and calibration method for seawater carbon dioxide meter

Technical field

The invention belongs to the field of carbon dioxide detectors, specifically a seawater carbon dioxide measuring instrument calibration system and a calibration method thereof.

Background technique

Accurately measuring the partial pressure of carbon dioxide in seawater is key to uncovering the ocean's role in global climate change. Generally speaking, there are two ways to obtain the partial pressure of carbon dioxide in seawater: continuous observation of carbon dioxide by navigation and long-term observation by fixed-point in-situ carbon dioxide sensors. Seawater carbon dioxide sensors based on permeable membrane technology can acquire a large amount of in-situ data and are widely used in research on global climate change in offshore, oceanic, polar and other sea areas and ocean acidification research in sensitive areas such as coral reefs. During long-term use of carbon dioxide sensors in the field, data drift will inevitably occur due to biological contamination and loss of components. Therefore, sensor calibration needs to be performed regularly.

Currently, in the existing technology, the same carbon dioxide partial pressure value in the same environment is used to calibrate underwater in-situ carbon dioxide measuring instruments, and corresponding to the same carbon dioxide partial pressure value, the calibration accuracy will be affected by the current environment, and At the same time, due to the low solubility of carbon dioxide in water and the slow dissolution rate, it becomes very difficult to change the carbon dioxide concentration in large volumes of water. There is a lack of an effective calibration method for quickly changing the carbon dioxide concentration; secondly, the existing Calibration methods all use standard detectors to measure directly. There is no calibration method that can determine the relationship between the standard value and the measured value of carbon dioxide partial pressure. As a result, only the same carbon dioxide partial pressure value can be measured in the same environment. As a result, there is also a carbon dioxide detection device. These devices directly use a spray water gas balancer to extract the CO ₂ in the water sample and then pass it into a standard detector for detection. However, there is a deviation in the extraction process itself. And the unique extraction result will also lead to errors in the subsequent calibration process of the carbon dioxide measuring instrument.

Therefore, establishing a seawater carbon dioxide meter calibration system and its calibration method will provide timely and accurate calibration services for seawater carbon dioxide sensors during their use, which will help to better play the importance of seawater carbon dioxide sensors in marine scientific research activities. effect.

Contents of the invention

The purpose of the present invention is to provide a seawater carbon dioxide meter calibration system and a calibration method thereof, so as to solve the problem in the prior art that the carbon dioxide meter calibration device is inaccurately calibrated and has no corresponding accurate calibration method.

The technical solution adopted by the present invention to achieve the above purpose is: a calibration method of a seawater carbon dioxide measuring instrument calibration system, which includes the following steps:

S1: Input a variety of standard gases with different carbon dioxide partial pressure value gradients, and check and calibrate the standard detector multiple times;

S2: After completing the calibration of the standard detector, calibrate the balancer component;

S3: The calibration work begins, open the waterway, observe and compare the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time, obtain the compared data, and complete the calibration of the underwater in-situ carbon dioxide measuring instrument;

S4: Record and process the compared data to obtain the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument.

The multiple inspection and calibration of the standard detector includes the following steps:

S1.1: Start the standard detector and preheat for 30 minutes. At this time, the water circulation component stops working;

S1.2: Adjust the two-way four-way valve of the balancer assembly so that the standard gas path is connected, that is, the three-way valve, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are connected in series to form a connected The gas flows to the channel and is connected to the standard detector after forming the channel;

S1.3: Input multiple standard gases with different gradients to the standard detector through the multi-way valve of the standard gas component, and calibrate the standard detector. After the calibration is completed, the gas flowing out of the standard detector is transported to the cross valve, then flows to the three-way reversing valve and is discharged to the atmosphere through the exhaust line.

Calibrating the balancer assembly includes the following steps:

S2.1: The water circuit circulation route is still closed, install the gas circuit inspection device to the balance membrane in the balancer assembly;

S2.2: Adjust the two-way four-way valve to connect the balanced gas path, that is, the air chamber, condenser, air pump, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are connected in series to form a connected gas flow to the passage, and then connect to the standard detector;

S2.3: Change the three-way valve in the standard gas line so that the gas from the three-way valve flows into the balancer gas line inspection device;

S2.4: The input standard gases with different gradients pass through the multi-way valve, go to the three-way valve, then enter the balancer gas path inspection device, then pass through the balance membrane, flow into the balance gas path, and then enter the standard detector;

S2.5: Verify whether the balance system is working properly by recording the output value of the standard detector and comparing it with the standard gas.

The step S3 is specifically:

S3.1: Close the multi-way valve to cut off the gas path of the standard gas, disassemble the gas path inspection device on the balance membrane, and install the water path flow device at the original position of the gas path inspection device of the balance membrane in the balancer assembly;

S3.2: Open the water circuit circulation component, and the water in the water storage container is transported to the water circuit flow device through the water circuit diverter and flow controller through the output pipeline. At this time, through the action of the balancing membrane, the water flows back to the water storage container;

The carbon dioxide in the water passes through the balance membrane, enters the air chamber, and opens the balance gas path, allowing the carbon dioxide in the water storage container to enter the standard detector;

S3.3: Real-time observation and comparison of data from standard detectors and underwater in-situ carbon dioxide measuring instruments;

S3.4: Inject acid-base adjustment solution into the water storage container multiple times to make the partial pressure of carbon dioxide in the water show different gradients, conduct multiple measurements, and record the data;

The acid-base adjustment solution is either a 0.5 mol/L dilute hydrochloric acid solution or a 0.5 mol/L sodium hydroxide solution;

Adjust the solution by injection so that there are at least 5 different gradients of carbon dioxide partial pressure in the water, including the zero point gradient, and the difference in carbon dioxide partial pressure between each two adjacent gradients is not less than 200 ppm.

The calibration coefficient of the underwater in-situ carbon dioxide measuring instrument is obtained, specifically:

The relationship between the standard value and the measured value is obtained through polynomial fitting, and R ² >0.999, that is:

y＝Ax ³ +Bx ² +Cx+D

Among them, y is the standard value, x is the measured value, and A, B, C, and D are polynomial fitting coefficients respectively.

A seawater carbon dioxide measuring instrument calibration system, including: a water storage container, a temperature controller, a water circulation component, a balancer component, a standard detector and a standard gas component;

An underwater carbon dioxide measuring instrument is provided in the water storage container; the circulation loop of the temperature controller passes through the inside of the water storage container to maintain the temperature in the water storage container;

One end of the water circulation component is connected to the water outlet end of the water storage container, and the other end is connected to the balancer assembly. The balancer assembly is connected to the return end of the water storage container through a water pipe;

The calibration gas component includes: a multi-way valve, a gas flow controller, and a three-way valve;

Multiple sets of standard gases are connected in parallel to each corresponding valve of the multi-way valve, and the multi-way valve is connected to the three-way valve through a gas line;

The gas flow controller is disposed on the gas path between the multi-way valve and the three-way valve to control the flow of gas into the three-way valve;

The other two output ends of the three-way valve are respectively connected to the standard detector and balancer components through pipelines.

The balancer component includes a balancer and a balance membrane provided on the balancer, an air chamber, a water flow device, a gas path inspection device and a gas path component;

The water path overflow device or the gas path inspection device is installed on the balance membrane and is located outside the balancer. The water path overflow device is connected to the water path circulation component, and the gas path inspection device is connected to the three components. The valve is connected; the air chamber is connected to the standard detector through the gas path assembly;

The gas path components include: a condenser, an air pump, a two-way four-way valve, a barometer, a cross four-way valve, and a gas drying tube connected to a standard detector;

The input end of the condenser is connected to the air chamber, and the output end is connected to the first port of the two-way four-way valve through an air pump, so that the air in the air chamber is extracted through the air pump and transported to the two-way four-way valve through the condenser. valve;

The second port of the two-way four-way valve connects the gas extracted by the air pump to the standard detector through the barometer, the cross four-way valve, and the gas drying pipe;

The third port of the two-way four-way valve serves as the input end and is connected to the three-way valve of the calibration gas assembly;

The fourth port of the two-way four-way valve serves as the output end and is connected to the input end of the three-way valve, and is discharged to the atmosphere through the exhaust pipeline on the output end of the three-way valve.

The air pump, two-way four-way valve, barometer, cross four-way valve and gas drying pipe are fixed in the installation room, and the condenser is fixed outside the balancer;

The standard detector extends a pipeline and is connected to the four-way cross valve of the gas line assembly. The output end of the four-way cross valve is connected to the three-way reversing valve through the pipeline. The two outlets of the three-way reversing valve are connected to the balance respectively. membrane chamber and exhaust line.

The water storage container is equipped with arranged water inside, and is connected with an acid-base injection device to modulate the water in the water storage container into an acid-base adjustment solution;

The adjusting solution is either 0.5 mol/L dilute hydrochloric acid solution or 0.5 mol/L sodium hydroxide solution;

Adjust the solution by injection so that there are at least 5 different gradients of carbon dioxide partial pressure in the water, including the zero point gradient, and the difference in carbon dioxide partial pressure between each two adjacent gradients is not less than 200 ppm.

The invention has the following beneficial effects and advantages:

1. Before calibrating the underwater in-situ carbon dioxide measuring instrument, the present invention first uses different gradients of carbon dioxide partial pressure values to calibrate the standard detector in the system, and then uses the inspected standard detector to calibrate the balancer assembly. Ensure that all components and components in the entire system are accurate before calibration, which can minimize interference from the external environment. Then open the waterway, observe and compare the data of the standard detector and the underwater in-situ carbon dioxide meter in real time, and achieve high accuracy. testing and calibration.

2. The present invention uses multiple sets of standard gases, which contain different gradients of carbon dioxide partial pressure values, to calibrate the standard detector multiple times by connecting multiple sets of standard gases in parallel with the multi-way valve and then connecting them to the three-way valve. The balancer components are calibrated with the inspected standard detector to ensure that each component and component in the entire system is accurate before calibration. Moreover, a gas path component is designed in the balancer component to dry the carbon dioxide gas that can penetrate well from the water path, and then pass it into the standard detector, making the calibration system accurate.

Description of the drawings

Figure 1 is a schematic flow chart of the calibration method of the structure of the present invention;

Figure 2 shows the water path and gas path flow diagram of the calibration system when the calibration standard detects gas;

Figure 3 shows the flow diagram of the water path and air path of the calibration system when calibrating the balancer component;

Figure 4 shows the water and gas flow diagram of the entire system when calibrating the underwater in-situ carbon dioxide measuring instrument;

Figure 5 is a linear diagram of the random underwater in-situ carbon dioxide measuring instrument of this embodiment;

Among them, 1 is the casing, 2 is the balance membrane chamber, and 3 is the water flow device.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

As shown in Figure 1, it is a schematic flow chart of the calibration method of the structure of the present invention. The calibration method of a seawater carbon dioxide measuring instrument calibration system of the present invention includes the following steps:

S1. Preparatory work;

S2. By inputting standard gases with different partial pressure gradients of carbon dioxide, the standard detector is inspected and calibrated multiple times;

S3. Calibrate the balancer component;

S4. The calibration work begins, open the waterway, observe and compare the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time;

S5. Record, process data, and obtain calibration coefficients.

The preparatory work in step S1 is as follows:

S1.1 preparation

S1.1.1 Clarify the specific usage environment of the underwater in-situ carbon dioxide meter, including the carbon dioxide partial pressure measurement range and the ambient temperature range, so as to determine the calibration range and calibration ambient temperature of the underwater in-situ carbon dioxide meter;

The calibration range of the underwater in-situ carbon dioxide measuring instrument needs to cover the measuring range of carbon dioxide partial pressure in the operating environment; the calibration ambient temperature of the underwater in-situ carbon dioxide measuring instrument is set to the median of the operating ambient temperature range;

S1.1.2 Prepare a sufficient amount of deionized water, prepare at least 5 gradients of high-pressure standard gas, prepare buffer reagents: sodium carbonate and sodium bicarbonate, and prepare an adjustment solution

S1.2 Check:

Check that the connections of each component of the system are intact and that the air tightness of the connections is intact; check whether each component is working properly.

S1.3 Adjust calibration environment

S1.3.1 Set the laboratory air conditioner to the calibrated ambient temperature and turn on the laboratory ventilator;

S1.3.2 Fill the bucket with deionized water, and put 28g of sodium bicarbonate and 0.5g of sodium carbonate into the deionized water to simulate the seawater environment;

S1.3.3 Close each shunt valve of the water circulation system, keep only the main circulation pipeline, open the water pump, and maintain the circulation of experimental water for calibration;

S1.3.4 Turn on the temperature controller, set the target temperature to the calibration ambient temperature, start all underwater in-situ carbon dioxide measuring instruments to be calibrated, and keep this state for one night;

S1.3.5 Open the first-level pressure reducing valve of high-pressure gas and adjust the gas pressure to 2Bar. Open the second-level pressure reducing valve and adjust the gas pressure to 1Bar standard gas.

As shown in Figure 2, the specific steps of the calibration method of the standard detector in step S2 are:

S2.1 Start the standard detector and preheat for 30 minutes. At this time, the water circulation line stops working;

S2.2 Adjust the two-way four-way valve inside the balancer to connect the standard gas path, that is, the three-way valve, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are connected in series to form a connected gas flow direction. path, and then connect the standard detector;

S2.3 Input at least 5 standard gases with different gradients to the standard detector through the multi-way valve, and calibrate the standard detector. After the calibration is completed, the gas coming out of the standard detector returns to the cross four-way valve, and then flows to The three-way reversing valve is finally discharged with the exhaust pipe.

At least 5 gradient standard air, standard air must be used instead of standard carbon dioxide gas with pure nitrogen as the carrier gas. Five standard gases with different gradients, that is, the carbon dioxide partial pressure values in the standard gas are all different. The lowest point of the concentration range of the standard air must be 0 point (i.e., standard air without carbon dioxide), and the maximum point of the concentration range of the standard air must be able to cover the target. The maximum value of the calibration range, and the closer the better. Standard air is used as a reference to calibrate the standard detector and check the balancer.

Before each standard gas line is connected to the multi-way valve, it is connected to a two-stage pressure reducing valve, which can perform two-stage pressure reduction on the high-pressure standard air in the standard gas line and control the gas pressure to slightly higher than 1 Bar. During the working process, you can also control the opening and closing of the gas path by switching the secondary pressure reducing valve.

As shown in Figure 3, the specific method of calibrating the balancer component in step S3:

S3.1 The water circuit circulation route is still closed. Install the gas circuit inspection device to the balance membrane in the balancer assembly;

S3.2 Adjust the two-way four-way valve to connect the balanced gas path, that is, the air chamber, condenser, air pump, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are connected in series to form a connected gas flow direction. path, and then connect the standard detector;

S3.3 Change the three-way valve in the standard gas line so that the gas from the three-way valve flows into the balancer gas line inspection device;

S3.4 The input standard gases with different gradients pass through the multi-way valve, go to the three-way valve, then enter the balancer gas path inspection device, then pass through the balance membrane, flow into the balance gas path, and then enter the standard detector;

S3.5 records the output value of the standard detector and compares it with the standard gas to verify whether the balance system is working properly.

As shown in Figure 4, the specific method of calibrating the underwater in-situ carbon dioxide measuring instrument in step S4:

S4.1 Close the standard gas path, remove the gas path inspection device from the balance membrane, and then install the water path flow device at the balance membrane in the balancer assembly;

S4.2 Open the waterway, and the water in the water storage container passes through the waterway component and leads to the waterway flow device. At this time, through the action of the balancing membrane, the water flows back into the water storage; the carbon dioxide in the water passes through the balancing membrane and enters the air chamber. Open the balance gas path so that the carbon dioxide in the water in the water storage container enters the standard detector;

S4.3 Real-time observation and comparison of data from standard detectors and underwater in-situ carbon dioxide measuring instruments;

S4.4 Inject the adjustment solution into the water storage container multiple times to make the partial pressure of carbon dioxide in the water show different gradients, conduct multiple measurements, and record the data.

The adjusting solution is a 0.5 mol/L dilute hydrochloric acid solution or a 0.5 mol/L sodium hydroxide solution;

And by injecting and adjusting the solution, at least 5 different gradients of carbon dioxide partial pressure can be separated in the water, including the zero point gradient. At the zero point, there is no need to prepare experimental water. The underwater in-situ carbon dioxide measuring instrument can be set up to close the external air circuit and return to zero internally for measurement. The difference in carbon dioxide partial pressure between two adjacent gradients is not less than 200ppm.

The measurement of the five gradients cannot be performed in increasing or decreasing order, and at least one gradient must be performed in an intersecting manner. For example: the planned gradient is: 0, 200, 400, 600, 800, then the actual measurement sequence can be 0, 200, 600, 400, 800.

When calibrating the underwater in-situ carbon dioxide measuring instrument, the five standard gases with different gradients do not pass through the multi-way valve, that is, the standard gas circuit does not work.

Step S5 processes the data and obtains calibration coefficients:

The relationship between the standard value and the measured value is obtained through polynomial fitting, and R ² >0.999, that is:

y＝Ax ³ +Bx ² +Cx+D

Among them, y is the standard value, x is the measured value, and A, B, C, and D are polynomial fitting coefficients respectively.

Combined with the calibration method of the present invention, as shown in Figure 4, the present invention proposes a seawater carbon dioxide measuring instrument calibration system, including: a water storage container, a temperature controller for constant temperature control of the water storage container, a water circuit circulation component, and a balancer Components, standard detectors, calibration gas components, and an underwater carbon dioxide measuring instrument is installed in the water storage container; the water storage container is used to simulate the seawater environment, and the carbon dioxide measuring instrument to be calibrated is placed in the water storage container;

One end of the water circuit circulation component is connected to the water outlet end of the water storage container, and the other end is connected to the balancer assembly. The balancer assembly is connected to the return end of the water storage container through a water pipe.

Water circuit circulation components, including: water circuit diverter, flow controller, input pipeline and output pipeline;

The input pipeline and the output pipeline are respectively connected to the input end and the output end of the water storage container. The input pipeline and the output pipeline constitute a circulation pipeline, and are divided at intervals through a water channel splitter; the water channel splitter passes through the flow rate The controller is connected to the waterway flow device.

The standard gas assembly includes multiple sets of standard gases, a multi-way valve, and a three-way valve. The multiple sets of standard gases are connected to the multi-way valve in a parallel manner. In this embodiment, the standard gases are divided into five groups, and each group of standard gases The air pressures are all 1 Bar. The five groups of different standard gases refer to the different partial pressure values of carbon dioxide inside the standard gas. The multi-way valve is equipped with 5 input ports and is connected to the three-way valve through a gas path. The gas path is set There is a gas flow controller, and the other two ends of the three-way valve are connected to the standard detector and balancer components through pipelines;

The balancer component includes: a balancer, a balance membrane located inside the balancer, an air chamber located behind the balance membrane, a water path flow device 2, a gas path inspection device, and a gas path assembly,

The manufacturer selected for the waterway overflow device 2 is: 4H-JENA ENGINEERING, Germany; model: CONTROSHydroC ^TM CO ₂ FT. The manufacturer selected for the waterway overflow device and gas path inspection device is: American LI-COR; model: LI-7815;

The water passage device 2 or the gas passage inspection device is installed outside the balance membrane. The two are calibrated to different systems and installed in the same position. The water passage device 2 is connected to the water circulation component, and the gas passage inspection device is connected to the said balance membrane. The three-way valve is connected, and the air chamber is connected to the standard detector through the gas path assembly.

In this embodiment, the water passage device 2 includes 1 water inlet pipe and 2 water outlet pipes;

The output end of the water storage container is connected to the water inlet pipe through the water flow diverter and the flow controller in turn; one of the water outlet pipes of the water flow overflow device is connected to the condenser, and the other water outlet pipe is connected to the water storage through the input pipe of the water circuit circulation assembly. The input side of the container is connected.

The gas path components include a condenser, an air pump, a two-way four-way valve, a barometer, a cross four-way valve, and a gas drying tube connected to the standard detector.

One end of the condenser is connected to the air chamber, and the other end is connected to the air pump. The air in the air chamber is extracted by the air pump, passes through the condenser, and is connected to one port of the two-way four-way valve. The second port of the two-way four-way valve is connected in series with the barometer, the cross four-way valve, and the gas drying pipe. The third port of the two-way four-way valve passes through the fourth port of the two-way four-way valve. A port and a three-way valve are connected to the exhaust pipeline.

The standard detector stretches out a pipeline and is connected to the four-way cross valve. The four-way cross valve is connected to a three-way reversing valve through the pipeline. The two outlets of the three-way reversing valve are connected to the balance membrane and the exhaust pipeline respectively. A three-way valve is also installed on the exhaust pipeline, and the three-way valve is also connected to the dual-way four-way valve.

The balancer includes a casing 1. The front end of the casing 1 is provided with a circular balance membrane chamber 2. An installation chamber is provided in the casing 1. The balance membrane is vertically fixed in the balance membrane cavity 2. A water passage device is provided. 3. Or the gas path inspection device is fixed on the balance membrane chamber 2 through bolts, the air pump, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are all fixed in the installation room, and the condenser is located in the Balancer external.

The water storage container is preferably a bucket, wrapped with an insulation layer to reduce temperature exchange with the outside world. The interior is equipped with configured experimental water for calibration, and the exterior is connected to the water system.

The temperature controller flows the temperature-controlled water path in the temperature controller through the inside of the bucket, so that the temperature controller can accurately and stably control the temperature of the experimental water inside the bucket.

Water circulation components include:

For waterway diversion, use PVC or PPR material pipelines and valves to create a multi-channel design to allow the water flow in the pipeline to flow or divert in a predetermined direction;

The water pump is connected to the main pipeline and pumps the experimental water in the bucket to the water system to generate circulating power;

The balance pipeline uses a hose made of non-carbon dioxide permeable material, and connects a branch of water from the shunt system of the water circulation system to the water path overflow device of the balancer, and introduces water circulation into the water circulation system;

The water flow controller is installed in the inlet pipeline of the balance pipeline and can control the stable flow of experimental water into the balancer waterway flow device.

Example 1:

As shown in Figure 4, the standard detector is first calibrated. The calibration method is to use five sets of standard gases with different carbon dioxide partial pressure gradients to pass through the multi-way valve, and then through the three-way valve. The gas enters the dual-way four-way valve in the balancer assembly. The second and third ends of the two-way four-way valve are connected, and then enter the barometer, then the cross four-way valve, the gas drying tube, and finally the standard detector. After this step is completed, calibrate the balancer assembly. When calibrating the standard detector and balancer assembly, the water flow is in a closed state. The gas path inspection device is fixed on the front end of the balance membrane, replacing the position of the water path flow device 3. Five sets of standard gases with different carbon dioxide partial pressure gradients pass through the multi-way valve, then the three-way valve, and enter the balancer inspection device. After passing through the balance membrane, the gas sequentially enters the condenser, air pump, and the first and second ports of the two-way four-way valve. Connect the end, then enter the barometer, four-way cross valve, gas drying tube, and finally enter the standard detector to calibrate the balancer assembly.

After the calibration of the standard detector and balancer components is completed, calibrate the underwater carbon dioxide measuring instrument. Remove the air path inspection device from the balance membrane, and then install the water path overflow device 3 on the balance membrane chamber in the balancer assembly; open the water path, and the water in the water storage container passes through the water path assembly and leads to the water path overflow device 3. At this time, through the action of the balance membrane, the water flows back into the water storage container; the carbon dioxide in the water passes through the balance membrane and enters the air chamber, opening the balance air path, allowing the carbon dioxide in the water storage container to enter the standard detector, and the data is recorded.

Using this calibration system, take an underwater carbon dioxide in-situ measuring instrument and take 5 different gradients for calibration. The calibration data is shown in Table 1, in ppm:

Table 1

serial number Partial pressure value of underwater in-situ carbon dioxide measuring instrument Partial pressure value of standard detector 1 0.11 0 2 221.32 201.35 3 658.26 599.63 4 441.69 403.25 5 892.93 810.79

As shown in Figure 5, it is a linear graph of the random underwater in-situ carbon dioxide measuring instrument of this embodiment. The fitting formula in this embodiment is: y=-2E-08x ³ +2E-05x ² +0.9084x-0.1574 , where R ² =1;

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (9)

1. A calibration method for a seawater carbon dioxide measuring instrument calibration system, which is characterized in that it includes the following steps: S1: Input a variety of standard gases with different carbon dioxide partial pressure value gradients, and check and calibrate the standard detector multiple times; S2: After completing the calibration of the standard detector, calibrate the balancer component; S3: The calibration work begins, open the waterway, observe and compare the data of the standard detector and the underwater in-situ carbon dioxide measuring instrument in real time, obtain the compared data, and complete the calibration of the underwater in-situ carbon dioxide measuring instrument; S4: Record and process the compared data to obtain the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument. 2. The calibration method of a seawater carbon dioxide measuring instrument calibration system according to claim 1, characterized in that the multiple inspection and calibration of the standard detector includes the following steps: S1.1: Start the standard detector and preheat for 30 minutes. At this time, the water circulation component stops working; S1.2: Adjust the two-way four-way valve of the balancer assembly so that the standard gas path is connected, that is, the three-way valve, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are connected in series to form a connected The gas flows to the channel and is connected to the standard detector after forming the channel; S1.3: Input multiple standard gases with different gradients to the standard detector through the multi-way valve of the standard gas component, and calibrate the standard detector. After the calibration is completed, the gas flowing out of the standard detector is transported to the cross valve, then flows to the three-way reversing valve and is discharged to the atmosphere through the exhaust line. 3. The calibration method of a seawater carbon dioxide measuring instrument calibration system according to claim 1, characterized in that the calibration of the balancer assembly includes the following steps: S2.1: The water circuit circulation route is still closed, install the gas circuit inspection device to the balance membrane in the balancer assembly; S2.2: Adjust the two-way four-way valve to connect the balanced gas path, that is, the air chamber, condenser, air pump, two-way four-way valve, barometer, cross four-way valve, and gas drying pipe are connected in series to form a connected gas flow to the passage, and then connect to the standard detector; S2.3: Change the three-way valve in the standard gas line so that the gas from the three-way valve flows into the balancer gas line inspection device; S2.4: The input standard gases with different gradients pass through the multi-way valve, go to the three-way valve, then enter the balancer gas path inspection device, then pass through the balance membrane, flow into the balance gas path, and then enter the standard detector; S2.5: Verify whether the balance system is working properly by recording the output value of the standard detector and comparing it with the standard gas. 4. The calibration method of a seawater carbon dioxide measuring instrument calibration system according to claim 1, characterized in that the step S3 is specifically: S3.1: Close the multi-way valve to cut off the gas path of the standard gas, disassemble the gas path inspection device on the balance membrane, and install the water path flow device at the original position of the gas path inspection device of the balance membrane in the balancer assembly; S3.2: Open the water circuit circulation component, and the water in the water storage container is transported to the water circuit flow device through the water circuit diverter and flow controller through the output pipeline. At this time, through the action of the balancing membrane, the water flows back to the water storage container; The carbon dioxide in the water passes through the balance membrane, enters the air chamber, and opens the balance gas path, allowing the carbon dioxide in the water storage container to enter the standard detector; S3.3: Real-time observation and comparison of data from standard detectors and underwater in-situ carbon dioxide measuring instruments; S3.4: Inject acid-base adjustment solution into the water storage container multiple times to make the partial pressure of carbon dioxide in the water show different gradients, conduct multiple measurements, and record the data. 5. The calibration method of a seawater carbon dioxide meter calibration system as claimed in claim 4, wherein the acid-base adjustment solution is a dilute hydrochloric acid solution of 0.5 mol/L or a sodium hydroxide of 0.5 mol/L. Any kind of solution; Adjust the solution by injection so that there are at least 5 different gradients of carbon dioxide partial pressure in the water, including the zero point gradient, and the difference in carbon dioxide partial pressure between each two adjacent gradients is not less than 200 ppm. 6. The calibration method of a seawater carbon dioxide measuring instrument calibration system as claimed in claim 1, characterized in that the calibration coefficient of the underwater in-situ carbon dioxide measuring instrument is obtained, specifically: The relationship between the standard value and the measured value is obtained through polynomial fitting, and R ² >0.999, that is: y＝Ax ³ +Bx ² +Cx+D Among them, y is the standard value, x is the measured value, and A, B, C, and D are polynomial fitting coefficients respectively. 7. A seawater carbon dioxide measuring instrument calibration system, characterized by including: a water storage container, a temperature controller, a water circulation component, a balancer component, a standard detector and a standard gas component; An underwater carbon dioxide measuring instrument is provided in the water storage container; the circulation loop of the temperature controller passes through the inside of the water storage container to maintain the temperature in the water storage container; One end of the water circulation component is connected to the water outlet end of the water storage container, and the other end is connected to the balancer assembly. The balancer assembly is connected to the return end of the water storage container through a water pipe; The calibration gas component includes: a multi-way valve, a gas flow controller, and a three-way valve; Multiple sets of standard gases are connected in parallel to each corresponding valve of the multi-way valve, and the multi-way valve is connected to the three-way valve through a gas line; The gas flow controller is disposed on the gas path between the multi-way valve and the three-way valve to control the flow of gas into the three-way valve; The other two output ends of the three-way valve are respectively connected to the standard detector and balancer components through pipelines. 8. A seawater carbon dioxide measuring instrument calibration system according to claim 7, characterized in that the balancer assembly includes a balancer and a balance membrane, an air chamber, a water passage device, and a gas passage provided on the balancer. Inspection devices and gas circuit components; The water path overflow device or the gas path inspection device is installed on the balance membrane and is located outside the balancer. The water path overflow device is connected to the water path circulation component, and the gas path inspection device is connected to the three components. The valve is connected; the air chamber is connected to the standard detector through the gas path assembly; The gas path components include: a condenser, an air pump, a two-way four-way valve, a barometer, a cross four-way valve, and a gas drying tube connected to a standard detector; The input end of the condenser is connected to the air chamber, and the output end is connected to the first port of the two-way four-way valve through an air pump, so that the air in the air chamber is extracted through the air pump and transported to the two-way four-way valve through the condenser. valve; The second port of the two-way four-way valve connects the gas extracted by the air pump to the standard detector through the barometer, the cross four-way valve, and the gas drying pipe; The third port of the two-way four-way valve serves as the input end and is connected to the three-way valve of the calibration gas assembly; The fourth port of the two-way four-way valve serves as the output end and is connected to the input end of the three-way valve, and is discharged to the atmosphere through the exhaust pipeline on the output end of the three-way valve. The air pump, two-way four-way valve, barometer, cross four-way valve and gas drying pipe are fixed in the installation room, and the condenser is fixed outside the balancer; The standard detector extends a pipeline and is connected to the four-way cross valve of the gas line assembly. The output end of the four-way cross valve is connected to the three-way reversing valve through the pipeline. The two outlets of the three-way reversing valve are connected to the balance respectively. membrane chamber and exhaust line. 9. A seawater carbon dioxide measuring instrument calibration system according to claim 7, characterized in that the water storage container is equipped with configured water inside, and is connected with an acid-base injection device to convert the water in the water storage container. Water is prepared into an acid-base adjustment solution; The adjusting solution is either 0.5 mol/L dilute hydrochloric acid solution or 0.5 mol/L sodium hydroxide solution; Adjust the solution by injection so that there are at least 5 different gradients of carbon dioxide partial pressure in the water, including the zero point gradient, and the difference in carbon dioxide partial pressure between each two adjacent gradients is not less than 200 ppm.