Shipboard in-situ calibration device and method for seabed suspended sediment concentration profile probe

Abstract

The application discloses a ship-mounted in-situ calibration device and method for a seabed suspended sediment concentration profile probe, which comprises a cylindrical water tank main body, an ASM and a support frame thereof, a driving motor, a rotating paddle, a cylindrical support, a water pump and a valve. The method comprises the following steps: horizontally arranging the ASM in the water tank through the support frame; extracting in-situ seawater on the ship deck for calibration by using the water pump; driving the paddle by the motor to uniformly mix the water sample; and extracting the water sample by opening the water extraction valve at different time intervals, wherein the water extraction valve is arranged on the side of the water tank and is consistent with the measurement elevation of the ASM, is used for extracting the water sample at the same elevation of the ASM, and tests the consistency of each sensor of the ASM. The water sample concentration can well cover the in-situ concentration range under normal circumstances by sampling at different time intervals in the static water sedimentation process. The in-situ seawater is extracted on the spot for calibration, so that the difference between the particle size range and the concentration range of the sediment suspension liquid prepared in the laboratory and the actual observation station is avoided.

Description

TECHNICAL FIELD

[0001] The application relates to a ship-mounted in-situ calibration device and method for a seabed suspended sediment concentration profile probe, and belongs to the technical field of hydrological monitoring. BACKGROUND

[0002] The suspended sediment concentration is an important parameter for studying the sediment deposition of a port channel, channel transportation, water quality environment and soil erosion of a beach, and the suspended sediment content influences the erosion and deposition evolution process of an estuary and coastal zone. Therefore, the research on the suspended sediment concentration is of great significance for the design and protection of a coastal engineering.

[0003] Currently, the calibration methods for the suspended sediment content mainly include field calibration and indoor calibration. The field calibration refers to the correspondence between the turbidity data recorded by an OBS optical instrument on site and the suspended sediment concentration of a water sample collected synchronously from the same water layer. The traditional field calibration method is to use a hydrological winch to collect on-site suspended sediment water samples at different times and in different water layers. However, this method has the disadvantage of sampling difficulty, such as the inability to simultaneously collect multiple layers of suspended sediment water samples on the same vertical line, low sampling efficiency, and the difficulty in collecting dynamic change information of the suspended sediment concentration in space and time under poor hydrological conditions, thereby leading to low suspended sediment inversion accuracy. Most of the existing indoor suspended sediment concentration calibration practical new devices are to collect water samples on site and then configure water samples with different suspended sediment concentrations indoors, stir them uniformly, and then use optical and acoustic instruments to measure. Then, the water sample near the measuring instrument is extracted to obtain the suspended sediment concentration by the filtering and weighing method for calibration. For example, the "indoor suspended sediment concentration calibration device" (201620122898.4) designed by Huaihai Institute of Technology can only perform single-point measurement of the OBS when in use. The "multifunctional suspended sediment concentration calibration system" (201721812644.6) designed by East China Normal University cannot extract water samples at different water levels at the same time. The "device for indoor OBS dynamic continuous calibration of suspended sediment concentration" (201910323620.1) designed by the International Energy Bureau of the Ministry of Water Resources and the Ministry of Transport of the People's Republic of China, Nanjing Hydraulic Research Institute, needs to configure water samples with known concentrations when in use, but indoor configuration of water samples can easily lead to differences in the particle size range and concentration range of the suspended liquid from the actual observation station.

[0004] The seabed suspended sediment concentration profile measuring instrument (ASM) is the most advanced seabed suspended sediment concentration profile measuring instrument at present, mainly used for high-resolution measurement in moving water, recording reflection results and dynamic parameters to create the movement condition of solid particles in the measuring plane in multidirectional flow. It is composed of a series of OBS backscattering infrared sensor arrays, thereby generating a turbidity profile. The directly measured signal is an optical reflection signal, so calibration work needs to be carried out before use, and the quantitative conversion relationship between each sensor and the corresponding actual suspended sediment concentration needs to be established. However, at present, there is no suspended sediment concentration profile in-situ calibration device suitable for ASM. SUMMARY

[0005] The present application overcomes the deficiencies in the prior art and provides a ship-borne in-situ calibration device and method for a seabed suspended sediment concentration profile probe.

[0006] A ship-borne in-situ calibration device for a seabed suspended sediment concentration profile probe, characterized in that: it comprises a transversely arranged cylindrical water tank, one end of the cylindrical water tank is provided with a water tank cover, the other end is connected with a water pump through a water suction pipe to extract in-situ seawater; an ASM support frame is fixed at the end without the water tank cover inside the cylindrical water tank, a suspended sediment concentration profile measuring instrument is installed in the ASM support frame, and the suspended sediment concentration profile measuring instrument sensor is downward to avoid the interference of deposited sediments with optical measurement; the suspended sediment concentration profile measuring instrument and the ASM support frame are externally sleeved with a cylindrical support, a rotating paddle is installed on the side of the cylindrical support, the rotating paddle is driven by a driving motor outside the water tank cover through the cylindrical support to uniformly mix the suspended liquid in the water tank; a plurality of valves with water suction pipes are arranged on the side of the cylindrical water tank, and the valves are consistent with the elevation of the ASM measuring sensor to extract water samples at the same elevation of the ASM for detecting the consistency of the ASM sensor.

[0007] The cylindrical water tank is made of transparent acrylic material to prevent the water tank wall of other materials from blocking the light signal and affecting the measurement of the suspended sediment concentration profile measuring instrument.

[0008] The ship-borne in-situ calibration device for the suspended sediment concentration profile probe further comprises an integral support arranged at the bottom of the cylindrical water tank.

[0009] The cylindrical design of the water tank avoids the problem of dead angles existing in rectangular water tanks. In a rectangular water tank, there may be dead angles where suspended sediments accumulate during agitation, affecting the mixing and uniformity of the water body.

[0010] The innovation and advantages of the present application are as follows:

[0011] (1) Put forward a kind of shipborne in-situ suspended sediment concentration calibration device, can be extracted in-situ seawater by shipborne and various ways to calibrate, avoid the difference between the particle size range and concentration range of sediment suspension liquid configured when carrying out traditional indoor suspended sediment concentration calibration and the actual observation station.And the device can be carried out suspended sediment concentration calibration by shipborne, also can bring back the seawater extracted in-situ to carry out indoor suspended sediment concentration calibration.

[0012] (2) Put forward a kind of calibration method of ASM using uniform suspension static water settlement process. The ASM is transversely placed in the cylindrical water tank, so that all OBS sensors in the ASM are located at the same elevation. The calibration process starts from stopping the agitation of sediment, and stops physical agitation when the suspension is uniformly mixed. At this time, the suspension is in static water settlement state, and the concentration is different at different time of static water settlement, but the concentration of the suspension at the same elevation should be equal. At the same time of stopping physical agitation, open the water extraction valve on the side wall of the water tank, and extract the water sample at the same elevation of ASM at different time of static water settlement for calibration.

[0013] (3) Based on the same settlement test, the instrument calibration process can be completed, compared with the traditional method of carrying out multiple experiments to configure different concentrations, the present application does not need to manually configure multiple experiments with different concentrations to carry out calibration, which is more simple. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The front view of the cylindrical water tank of the present application.

[0015] Figure 2 The front view of the stirring device of the present application.

[0016] Figure 3 The schematic diagram of the overall structure of the present application.

[0017] Figure 4 The side view of the present application.

[0018] Wherein, 1, cylindrical water tank, 2, water tank cover, 3, driving motor, 4, cylindrical support, 5, rotating paddle, 6, ASM support frame, 7, suspended sediment concentration profile measuring instrument, 8, valve, 9, water extraction pipe, 10, water extraction pump, 11, overall support EMBODIMENT

[0019] As Figures 1-4As shown, the concept of the present application is: first, to provide a shipboard in-situ calibration device for suspended sediment concentration profile measurement, the cylindrical water tank 1 is transversely laid, the ASM 7 is transversely placed in the water tank, and is fixed by the ASM support frame 6; the water pump 10 on the side of the cylindrical water tank 1 without the water tank cover 2 is used to extract in-situ seawater; the driving motor 3 is turned on to drive the rotating paddle 5 to rotate, so that the suspended sediment in the cylindrical water tank 1 is uniformly mixed. At the same time, a calibration method is provided, when the suspended sediment is uniformly mixed, stop physical stirring, so that the suspended sediment is in a static water settling state, the concentration is different at different time of static water settling, the water samples at the same height of ASM at different time are extracted, dried, filtered and calculated to obtain the suspended sediment concentration, and regression analysis is performed on the optical signals measured by the ASM to obtain the calibration formula.

[0020] As shown in Figures 1-4 A shipboard in-situ calibration device for suspended sediment concentration profile probe, characterized in that: it comprises a transversely laid cylindrical water tank 1, one end of the cylindrical water tank 1 is provided with a water tank cover 2, the other end is connected with a water pump 10 through a water suction pipe for extracting field water samples; the cylindrical water tank 1 has an ASM support frame 6 fixed at one end without the water tank cover 2, which can transversely fix the suspended sediment concentration profile measurement instrument 7 in the cylindrical water tank 1, and the sensor of the suspended sediment concentration profile measurement instrument 7 is downward to avoid the interference of the deposited sediment on the optical measurement; the suspended sediment concentration profile measurement instrument 7 and the ASM support frame 6 are externally sleeved with a cylindrical support 4, the side of the cylindrical support 4 is provided with a rotating paddle 5, the rotating paddle 5 is driven by a driving motor 3 outside the water tank cover 2 through the cylindrical support 4 to uniformly mix the suspended sediment in the water tank; the side of the cylindrical water tank 1 is provided with a plurality of valves 8 with water suction pipes 9, and the valves 8 are consistent with the elevation of the ASM measurement sensor, which is used to extract water samples at the same height of ASM to detect the consistency of the ASM sensor.

[0021] The cylindrical water tank 1 is made of transparent acrylic material to prevent the water tank wall from affecting the ASM measurement.

[0022] The bottom of the cylindrical water tank 1 is provided with an integral support 11 for maintaining the stability of the entire system on the deck of the ship.

[0023] As shown in Figure 2 The stirring device is composed of the driving motor 3, the cylindrical support 4 and the rotating paddle 5. The driving motor 3 drives the rotating paddle 5 to rotate through the cylindrical support 4, so that the suspended sediment in the cylindrical water tank 1 is uniformly mixed.

[0024] The method for in-situ calibration of suspended sediment concentration profile measurement by using the above device is characterized by comprising the following steps:

[0025] First step: Put the suspended sediment concentration profile measuring instrument 7 through the ASM support frame 6 horizontally in the cylindrical water tank 1, with the OBS sensor measuring surface of the suspended sediment concentration profile measuring instrument 7 facing downward to prevent the sediment from falling and blocking the sensor during the experiment.

[0026] Second step: Put the cylindrical support 4 of the rotating paddle 5 into the cylindrical water tank 1, outside the ASM support frame 6, then cover the water tank cover 2, and connect the cylindrical support 4 with the rotating shaft of the driving motor 3.

[0027] Third step: Turn on the water pump 10 on one side of the cylindrical water tank 1 to suck in a predetermined mass of seawater and sediment.

[0028] Fourth step: Turn on the driving motor 3 to drive the rotating paddle 5 to rotate through the cylindrical support 4, so that the suspended sediment in the cylindrical water tank 1 is uniformly mixed; at the same time, turn on the suspended sediment concentration profile measuring instrument 7 to measure.

[0029] Fifth step: After uniform mixing, stop physical agitation to make the suspended sediment in a state of static water settlement, at this time the concentration at the same elevation in the cylindrical water tank 1 should be always equal, open the valve 8 on the side wall of the water tank, and extract water samples at the same elevation as the ASM 7 at different times of static water settlement.

[0030] Sixth step: After the settlement process is completely finished, stop measuring and read the data.

[0031] Seventh step: Since all OBS sensors in the ASM are at the same elevation, the measured optical signals should be equal, so perform consistency test on the obtained optical signals, if the consistency test passes, it means that all OBS sensors are uniform, if there is deviation in some sensors, further individual calibration is needed.

[0032] Eighth step: Dry and filter the water samples extracted at different times and calculate the suspended sediment concentration, and perform correlation regression analysis with the corresponding optical signal values measured by the ASM, through data regression, build the quantitative relationship between the optical signal measured by the ASM and the actual concentration of the water sample filtered.

Claims

1. A shipborne in-situ calibration device for a seabed suspended sediment concentration profile probe, characterized in that: The system includes a horizontally arranged cylindrical water tank (1), one end of which is equipped with a tank cover (2), and the other end is connected to a water pump (10) via a water pipe to extract in-situ seawater; an ASM support frame (6) is fixed inside the cylindrical water tank (1) at the end without the tank cover (2), and a suspended sediment concentration profiler (7) is installed inside the ASM support frame (6), with the sensor of the suspended sediment concentration profiler (7) facing downwards to avoid interference from sediment from the optical measurement; the suspended sediment concentration profiler... The surface measuring instrument (7) and the ASM support frame (6) are fitted with a cylindrical bracket (4). A rotating blade (5) is installed on the side of the cylindrical bracket (4). The rotating blade (5) is driven by a drive motor (3) on the outside of the water tank cover (2) through the cylindrical bracket (4) to make the suspension in the water tank evenly mixed. The side of the cylindrical water tank (1) is provided with multiple valves (8) with water pumping pipes (9), and the valves (8) are at the same elevation as the ASM measuring sensor, for extracting water samples at the same elevation as the ASM.

2. The shipborne in-situ calibration device for the seabed suspended sediment concentration profile probe as described in claim 1, characterized in that: The cylindrical water tank (1) is made of transparent acrylic material.

3. The shipborne in-situ calibration device for the seabed suspended sediment concentration profile probe as described in claim 1, characterized in that: It also includes an integral support (11) set at the bottom of the cylindrical water tank (1).

4. A method for in-situ calibration of suspended sediment concentration profile measurements using any one of the devices described in claims 1-3, characterized in that: Includes the following steps: Step 1: Place the suspended sediment concentration profile measuring instrument (7) horizontally in the cylindrical water tank (1) through the ASM support frame (6), so that the OBS sensor measuring surface of the suspended sediment concentration profile measuring instrument (7) is facing downwards, to prevent sediment from falling and obstructing the sensor during the experiment. Step 2: Place the cylindrical bracket (4) of the rotating blade (5) into the cylindrical water tank (1) and put it on the outside of the ASM support frame (6). Then cover the water tank with the cover (2) and connect the cylindrical bracket (4) to the shaft of the drive motor (3). Step 3: Turn on the water pump (10) on one side of the cylindrical water tank (1) to draw in the predetermined mass of seawater and sediment; Step 4: Turn on the drive motor (3) to drive the rotating blade (5) through the cylindrical bracket (4) to rotate, so that the suspension in the cylindrical water tank (1) is mixed evenly; at the same time, turn on the suspended sediment concentration profile measuring instrument (7) to measure; Step 5: After the mixture is evenly mixed, stop physical stirring and let the suspension settle in still water. At this time, the concentration at the same elevation in the cylindrical water tank (1) should always be equal. Open the valve (8) on the side wall of the water tank and extract water samples at the same elevation as ASM (7) at different times of still water settling. Step 6: Once the settlement process is completely finished, end the measurement and read the data; Step 7: Since all OBS sensors in ASM are located at the same elevation, the measured optical signals should be equal. Perform a consistency check on the acquired optical signals. If the consistency check passes, it means that all OBS sensors are consistent. If any sensor has a deviation, it needs to be calibrated separately. Step 8: Dry and filter water samples taken at different times and calculate the suspended sediment concentration. Perform correlation regression analysis with the corresponding optical signal values ​​measured by ASM. Through data regression, construct a quantitative relationship between the optical signal measured by ASM and the actual concentration of the filtered water sample.

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