CN111551687A - Underground water multi-inorganic parameter online detection system and method - Google Patents
Underground water multi-inorganic parameter online detection system and method Download PDFInfo
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- CN111551687A CN111551687A CN202010557918.1A CN202010557918A CN111551687A CN 111551687 A CN111551687 A CN 111551687A CN 202010557918 A CN202010557918 A CN 202010557918A CN 111551687 A CN111551687 A CN 111551687A
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Abstract
The invention discloses an on-line detection system and method for multiple inorganic parameters of underground water. The system comprises an intelligent controller, a water quality detection sensor and a water sample flow cell. The intelligent control instrument comprises a CPU control circuit which synchronously controls the connection and disconnection of the first relay and the second relay through the water pump control circuit so as to control the power-on starting and the power-off stopping of the sampling pump through the first relay and the second relay. The water sample outlet of the sampling pump is connected with the water sample inlet installed at the top of the water sample flow cell, the drain outlet is installed at the bottom of the water sample flow cell, the CPU control circuit controls the opening and closing of the drain outlet through the electromagnetic valve, the water quality detection sensor is installed in the water sample flow cell, and the water quality detection sensor is connected with the CPU control circuit. The invention transfers the detection of the inorganic parameters of the underground water from a laboratory to the field for on-line detection, does not need to be attended by personnel, and has high automation degree, high detection efficiency and high sampling accuracy.
Description
Technical Field
The invention relates to an underground water multi-inorganic parameter online detection system and an underground water multi-inorganic parameter online detection method based on the system, and belongs to the technical field of underground water inorganic parameter detection.
Background
At present, the detection of inorganic parameters of underground water at home and abroad still stays at the stage of on-site rapid detection and on-site sampling and then is brought back to laboratory analysis. On-site sampling tools are generally portable sampling devices, have small and single flow, and cannot realize ideal judgment on samples sampled in wells. In addition, at present, samples sampled on site are generally multilayer mixed water in a well, and in-situ water samples of underground independent aquifers are not collected, so that the truth of the samples is poor, the directivity of detection results is poor, and the scientific research utilization rate is low. The existing field running point sampling and manual detection mode has the problems of high labor intensity, few obtained data samples, discontinuous data, inaccurate data, insufficient reliability, easy data loss, difficult data arrangement and the like.
Disclosure of Invention
The invention aims to provide an underground water multi-inorganic parameter online detection system and method, which transfer underground water inorganic parameter detection from a laboratory to the field for online detection without personnel on duty, and have the advantages of high automation degree, high detection efficiency and high sampling accuracy.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a many inorganic parameters of groundwater on-line measuring system which characterized in that: it includes intelligent control appearance, water quality testing sensor and water sample flow-through cell, wherein: the intelligent control instrument comprises a CPU control circuit, the CPU control circuit synchronously controls the connection and disconnection of a first relay and a second relay through a water pump control circuit, so that the power-on starting and the power-off stopping of the sampling pump are controlled through the first relay and the second relay; the water sample outlet of the sampling pump is connected with the water sample inlet installed at the top of the water sample flow cell, the drain outlet is installed at the bottom of the water sample flow cell, the CPU control circuit controls the opening and closing of the drain outlet through the electromagnetic valve, the water quality detection sensor is installed in the water sample flow cell, and the water quality detection sensor is connected with the CPU control circuit.
An online detection method for multiple inorganic parameters of underground water based on the online detection system for multiple inorganic parameters of underground water is characterized by comprising the following steps:
1) sleeping;
2) judging whether a sampling command issued remotely is received: if yes, entering 3), otherwise, returning to 1);
3) judging the authenticity of the sampling command: if true, entering 4), otherwise returning to 1);
4) the electromagnetic valve is used for controlling the drainage port to be closed, then the water pump control circuit is used for controlling the first relay and the second relay to be conducted so as to start the sampling pump, and the water sample flow cell starts to collect water samples;
5) starting the water quality detection sensor;
6) whether the water quality detection sensor is soaked in a water sample or not is judged based on the pressure signal detected by the water quality detection sensor: if the water sample is soaked, entering 7), otherwise, repeatedly executing 6);
7) the water quality detection sensor detects actual conductivity at intervals and judges whether a water sample is stable or not based on multiple times of actual conductivity detected at intervals: if the water sample is stable, entering 8), otherwise, repeatedly executing 7);
8) the water quality detection sensor detects temperature, pressure and actual conductivity at intervals, and calculates other inorganic parameters;
9) the water quality detection sensor stores all obtained inorganic parameter data and sends the data to a remote center;
10) the remote center issues a sampling stopping command, finishes and returns to 1).
The invention has the advantages that:
the system is installed in the field, the detection of the inorganic parameters of the underground water is transferred from a laboratory to the field for on-line detection, various inorganic parameters of the underground water can be timely and automatically sampled and detected without the need of personnel on duty, the time and labor are saved, the detection efficiency is high, the truth of the sample is high, the directivity of the detection result is good, the scientific research utilization rate is high, the obtained data samples are multiple, the data is continuous, accurate and reliable, the data can be timely stored, the arrangement is convenient, and the system can be widely applied to engineering such as hydrogeological investigation, regional water pollution quality investigation, polluted site restoration and the like.
The method has the function of judging the stability of the water sample on one hand, and adopts zero drift compensation during data acquisition on the other hand, so that the truth of the sample is ensured, and the accuracy and the reliability of the acquired data are improved.
Drawings
FIG. 1 is a schematic diagram of the composition of the groundwater multi-inorganic parameter online detection system of the invention.
FIG. 2 is a schematic diagram of a voltage regulator circuit.
Fig. 3 is a schematic diagram of a water pump control circuit.
Fig. 4 is a schematic structural view of a water quality detection sensor.
Fig. 5 is a schematic structural view of a sensor core.
Fig. 6 is a schematic structural diagram of a water sample flow cell.
Fig. 7 is a schematic right view of fig. 6.
Fig. 8 is a schematic left side view of fig. 6.
Fig. 9 is an equivalent circuit schematic diagram of the acquisition voltage signal.
Fig. 10 is a schematic diagram of the centrosymmetric distribution of four piezoresistors.
Detailed Description
Referring to fig. 1 to 8, the groundwater multi-inorganic parameter online detection system of the present invention is disposed on the ground beside a field sampling well, referring to fig. 1, the groundwater multi-inorganic parameter online detection system of the present invention comprises an intelligent controller 30, a water quality detection sensor 60 and a water sample flow cell 50, wherein: the intelligent controller 30 comprises a CPU control circuit 32, wherein the CPU control circuit 32 synchronously controls the on and off of a first relay K1 and a second relay K2 through a water pump control circuit 33, so as to control the power-on start and the power-off stop of the sampling pump 20 through a first relay K1 and a second relay K2; the sampling pump 20 is arranged at a detection point under a sampling well and used for collecting an in-situ water sample of an underground independent aquifer, a water sample outlet of the sampling pump 20 is connected with a water sample inlet 53 arranged at the top of the water sample flow cell 50 through a pipeline, a drain outlet 54 is arranged at the bottom of the water sample flow cell 50, the CPU control circuit 32 controls the opening and closing of the drain outlet 54 through an electromagnetic valve 58, a water quality detection sensor 60 is arranged in the water sample flow cell 50, and a signal port of the water quality detection sensor 60 is connected with a corresponding signal port of the CPU control circuit 32 through a standard communication interface RS 485.
In the present invention, the sampling pump 20 with low disturbance performance is an existing water pump in the field, and different types of water pumps can be selected according to the actual downhole situation, such as a peristaltic pump or a screw pump.
As shown in fig. 1, the intelligent controller 30 includes a power supply circuit including a voltage conversion circuit 311 for converting 220V ac power into 12V dc power and a voltage regulator circuit 312 for performing voltage regulation control output on the 12V dc power, wherein an input terminal of the voltage conversion circuit 311 is connected to the 220V ac power 10, and an output terminal of the voltage conversion circuit 311 is connected to power supply terminals of the CPU control circuit 32 and the water pump control circuit 33 via the voltage regulator circuit 312 to supply power to them.
In the present invention, the voltage converting circuit 311 may employ electronic circuits that are well-known in the art, and will not be described in detail herein.
As shown in fig. 2, the regulator 312 includes a chip U1 (e.g., MC34063 chip), which has good stability when converting between strong current and weak current, wide range of current carrying, wide application condition, and good voltage stability, and can control the output voltage VO to be 1.25(1+ R1/R2) according to the requirement.
In the present invention, the CPU control circuit 32 includes a CPU, which can be implemented by using a CPU integrated circuit that is well-known in the art, and therefore, will not be described in detail herein.
As shown in fig. 3, the water pump control circuit 33 includes an optical coupler U2, the control end IO 220V of the CPU control circuit 32 is connected with the input side of the optical coupler U2, the isolation output side of the optical coupler U2 is connected with the coils of the first relay K1 and the second relay K2 via a triode control circuit, the moving contacts of the first relay K1 and the second relay K2 are both connected with the 220V alternating current 10, and the normally open fixed contacts of the first relay K1 and the second relay K2 are respectively connected with the zero line input port and the live line input port of the sampling pump 20, wherein: the first relay K1 and the second relay K2 are in a normally open state; the triode control circuit comprises an NPN triode Q4 and a control resistor R31, the control resistor R31 is connected with coils of a first relay K1 and a second relay K2 in parallel and then connected to a collector of an NPN triode Q4, or the control resistor R31 is connected with coils of a first relay K1 and a second relay K2 in parallel and then connected between an isolation power supply VCC _ JDQ _ ISO and a collector of an NPN triode Q4, and a base of the NPN triode Q4 is connected with an isolation output side of an optical coupler U2.
In the present invention, the water pump control circuit 33 belongs to the weak current signal control strong current switch-off. In use, it can be found that when weak current equipment and strong current equipment are integrated, false triggering and safety problems are easily caused, therefore, the water pump control circuit 33 of the invention adopts double-channel control, namely synchronously controls the conduction and the disconnection of a zero line and a live line of the sampling pump 20, and the way can not only avoid false triggering and false disconnection of the sampling pump 20, but also avoid electric shock accidents of users. In addition, the water pump control circuit 33 adopts the isolation design of the optical coupler U2, because the sampling pump 20 belongs to inductive load and is easy to cause interference, and the interference problem can be well solved by power isolation realized by using the high-speed optical coupler.
As shown in fig. 1, the CPU control circuit 32 is also connected to a memory 34 in actual use.
As shown in fig. 1, the CPU control circuit 32 is also connected to the remote communication device 40 through a standard communication interface RS485/232 to respond to various commands sent from the remote center and to feed back sampled data to the remote center.
In the present invention, the remote communication device 40 is implemented by a wireless communication device, which is well-known in the art and therefore will not be described in detail herein.
Referring to fig. 1, 6 to 8, the water sampling flow cell 50 is a closed cell body, the water sampling flow cell 50 is divided into a first flow-through chamber 51 and a second flow-through chamber 52 which are isolated from each other at the bottom and are not communicated with each other at the top by a partition plate 501, the water sampling inlet 53 is located above the first flow-through chamber 51, a drain 54 is respectively installed below the first flow-through chamber 51 and the second flow-through chamber 52, the two drain 54 installed in the first flow-through chamber 51 and the second flow-through chamber 52 can be controlled independently or synchronously, the water quality detection sensor 60 is installed at the lower part of the second flow-through chamber 52, that is, close to but not in contact with the bottom surface of the second flow-through chamber 52, the upper part of the water sampling flow cell 50 is provided with an overflow port 55, the overflow port 55 is designed to drain excess waste water samples when the water amount is not controlled, and the whole water sampling flow cell 50 can.
In the present invention, the design of the first flow-through chamber 51 and the second flow-through chamber 52 can make the first flow-through chamber 51 perform the functions of precipitation and filtration on impurities such as silt in the water sample, so that the water sample flowing into the second flow-through chamber 52 is the water sample which is closest to the real state and has no impurities such as silt, thereby ensuring the accurate detection of the water sample by the water quality detection sensor 60.
In the practical design, the side wall of the water sample flow cell 50 is further provided with a large-flow sampling port 57 and a micro-flow sampling port 56, wherein the large-flow sampling port 57 is usually arranged in the middle or lower part of the side wall of the water sample flow cell 50, the large-flow sampling port 57 is connected with a relevant detection instrument via a switch valve, the micro-flow sampling port 56 is usually arranged on the upper part of the side wall of the water sample flow cell 50, the micro-flow sampling port 56 is connected with an upward-tilted flow guide pipe 560, a filtering device is arranged in the flow guide pipe 560, the outlet of the flow guide pipe 560 is higher than the water sample inlet 53, and when the micro-flow monitoring device is used, a water sample.
In the present invention, the water quality detecting sensor 60 is used to detect the temperature, pressure and actual conductivity of the water sample in real time, and based on the detected data, the water level, the exact conductivity (the conductivity at 25 ℃), the salinity, the total dissolved solids, the resistivity and the water density can be calculated, that is, the water quality detecting sensor 60 can collect the above nine inorganic parameters of the groundwater.
As shown in fig. 4 and 5, the water quality detecting sensor 60 includes a sensor cylinder 62, a sensor core 63 is clamped in an inner cavity of the sensor cylinder 62, a bottom opening of the sensor cylinder 62 is sealed by a head plug 61, i.e., the head plug 61 is screwed on the bottom opening of the sensor cylinder 62, a circuit board cylinder 64 is mounted on a top opening of the sensor cylinder 62, i.e., the top opening of the sensor cylinder 62 is screwed on the bottom opening of the circuit board cylinder 64, a circuit board 65 is mounted in the inner cavity of the circuit board cylinder 64, a male connector 66 is mounted on the top opening of the circuit board cylinder 64, i.e., the top opening of the circuit board cylinder 64 is screwed on the bottom opening of the male connector 66, the top of the male connector 66 is connected with a female connector 68 by a male connector fixing nut 67, a four-pin plug fixing sleeve 660 for fixing the four-pin plug 661 is arranged on the male connector 66 and the female connector 68, i.e., a four-pin plug 661 is mounted in a through cavity of the four, that is, the top opening of the female connector 68 is screwed with the bottom opening of the tail pressing cap 69, the lead wire led out from the sensor core 63 is connected with the signal input port of the circuit board 65, and the lead wire led out from the signal output port of the circuit board 65 passes through the circuit board barrel 64, then sequentially passes through the lead wire channels arranged on the male connector 66, the female connector 68 and the tail pressing cap 69 via the four-pin plug 661, and then is connected with the corresponding signal port of the CPU control circuit 32 via the detection cable.
In practical application, when the water quality detecting sensor 60 is not used, the top of the tail pressing cap 69 is covered with a cap 690, as shown in fig. 4.
As shown in fig. 4, the water quality detecting sensor 60 is vertically arranged in practical use, the head plug 61 at the left is at the bottom, and the tail pressing cap 69 at the right is at the top.
As shown in fig. 5, the sensor core 63 includes a main casing 630, an oil-filled cavity 631 is disposed at the top of the main casing 630, the oil-filled cavity 631 has a large-sized structure, the oil-filled cavity 631 extends downward to communicate with an upper groove 6301 formed at the bottom of the main casing 630, a silicon diaphragm 635 with a pressure measurement circuit formed by laser etching is disposed at the bottom of the upper groove 6301, a temperature measurement element 637 is disposed on the surface of the silicon diaphragm 635 facing the oil-filled cavity 631, the oil-filled cavity 631 is filled with a silicon oil 632 and then sealed by a sealing cap 638, a corrugated sheet 634 (existing component) is fixed at the bottom of the main casing 630 by an annular pressure ring 633, a gap is maintained between the corrugated sheet 634 and the silicon diaphragm 635 and filled with the silicon oil 636, an electrical conductivity sensor 639 is installed in the pressure ring 633, the electrical conductivity sensor 639 is located below the corrugated sheet 634 without contacting the corrugated sheet 634 and without covering and shielding the corrugated sheet 634, and a lead wire led from the pressure, The sealing cover 638 is connected to an output pin interface 6380 mounted on the outer side of the sealing cover 638, a lead wire led out from the conductivity sensor 639 passes through the pressure ring 633 and a through hole (not shown in the figure) formed in the main casing 630, and then is connected to the output pin interface 6380, the lead wire led out from the conductivity sensor 639 does not pass through the silicone oil 632 in the oil-filled cavity 631, and the output pin interface 6380 is connected to a signal input port of the circuit board 65.
As shown in fig. 4, a T-shaped water inlet channel is arranged on the head plug 61, the water inlet channel has two water inlets 613, the water inlets 613 are exposed, a water outlet 614 of the water inlet channel is communicated with an inner cavity of the sensor cylinder 62, the conductivity sensor 639 of the sensor core 63 faces the water outlet 614, liquid flowing out of the water outlet 614 generates uniform pressure action on the sensor core 63, so as to ensure the measurement accuracy of a voltage signal, and a conical head 611 which is convenient for reducing resistance when the water quality detection sensor 60 is put into a liquid environment is arranged at the bottom of the head plug 61.
As shown in fig. 4, a supporting and fixing wall 622 extends upward from the top of the sensor cylinder 62, and the supporting and fixing wall 622 may be in a shape of a cylinder, a semi-cylinder, a plate, and the like, without limitation, wherein: the supporting and fixing wall 622 extends into the inner cavity of the circuit board barrel 64 to firmly fix the circuit board 65; the supporting and fixing wall 622 is provided with a lead passage 621 for routing lead-out wires of the circuit board 65. The wire paths on the top of the circuit board barrel 64, the male connector 66, the female connector 68, and the tail cap 69 are understood by reference to the wire path 621 on the supporting fixed wall 622.
In practical design, an O-shaped waterproof ring (not shown in the figure) for ensuring sealing performance and realizing water resistance in a cavity can be installed between the connecting parts of the sensor cylinder 62 and the circuit board cylinder 64, between the connecting parts of the circuit board cylinder 64 and the male joint 66, between the connecting parts of the male joint 66 and the male-female joint fixing nut 660, and the like, and the O-shaped waterproof ring is preferably an O-shaped rubber sealing ring with high temperature and high pressure resistance.
In practical design, the temperature measuring element 637 is preferably a platinum resistor.
In practical designs, the silicon diaphragm 635 is made of single crystal silicon, and the voltage measuring circuit is a bridge circuit formed by overlapping four piezoresistors laser-etched on the surface of the silicon diaphragm 635, as shown in fig. 9, in which: the four piezoresistors have equal resistance values, and are distributed in a central symmetry manner, as shown in fig. 10.
In the present invention, the pressure measuring circuit or the bridge circuit is designed to externally lead three wires, one wire outputs a voltage signal, the other two wires are used for connecting the positive electrode and the negative electrode of the power supply, and the temperature measuring element 637 is designed to externally lead one wire for outputting a temperature signal. The conductivity sensor 639 is designed to draw out one wire for outputting an actual conductivity signal. These wires connect to output pins on output pin interface 6380.
The pressure measurement principle adopted by the sensor core 63 is as follows:
as shown in fig. 9 and 10, piezoresistors R1 to R4 for sensing voltage signals and having equal resistance are laser-etched on the surface of the silicon diaphragm 635 by using the piezoresistive effect of the silicon diaphragm 635, and the piezoresistors R1 to R4 are symmetrically distributed as bridge arm resistors and are connected in a bridge circuit.
When the silicon diaphragm 635 is under pressure, its shape and resistivity change, which results in a change in resistance of the silicon diaphragm 635 itself, that is, there is a mapping relationship between the pressure (strain) and the resistance, which can be expressed as follows:
in the above formula: pi is the piezoresistive coefficient of the material of the silicon diaphragm 635, E is the young modulus of the material of the silicon diaphragm 635, is the strain rate of the material of the silicon diaphragm 635, and upsilon is the poisson ratio of the material of the silicon diaphragm 635.
It can be seen that the resistance value of the semiconductor such as the silicon diaphragm 635 varies
Is formed by the combined action of the change of geometric dimension and the change of the motion state of the carrier.
In practical application, when the water quality detecting sensor 60 is immersed in a water sample, a liquid medium enters through the water inlet channel of the head plug 61, bypasses the conductivity sensor 639 to directly apply the pressure P to the corrugated plate 634, and then the corrugated plate 634 transmits the sensed pressure P to the silicon diaphragm 635 through the silicon oil 636.
When the resistance of the piezo-resistor on the silicon diaphragm 635 changes due to the pressure P, the balance state of the bridge circuit is damaged, so that the bridge circuit outputs a non-zero voltage signal Vout, which reflects the pressure, thereby achieving the purpose of measuring the pressure parameter.
Further, ideally, the resistances of the voltage dependent resistors R1-R4 in the bridge circuit are identical, and they are affected by external factors such as temperature, but when the external pressure P acts on the silicon diaphragm 635, the voltage response of the bridge circuit changes linearly.
As shown in fig. 9 and 10, setting the voltage signal Vout output by the bridge circuit to be a potential difference between two points B, D, and A, C two points for inputting the power supply voltage, the following equation is obtained:
Vout＝VB-VD
in the formula:
vin is an input power supply voltage, Δ R represents a resistance value change of the piezoresistor, and R1 ', R2', R3 'and R4' are resistance values of the piezoresistors R1 to R4 after the resistance value change.
Under an ideal state, assuming that the bridge arm resistances, i.e., the piezoresistors, are collectively denoted as R, and the pressure applied to the silicon diaphragm 635 is P, the voltage change Δ Vout output by the bridge circuit is:
as can be seen from the above formula, under the action of the pressure P, the voltage signal change Δ Vout output by the water quality detection sensor 60 is determined by the resistance change Δ R of the bridge arm resistor R in the bridge circuit. Therefore, it can be concluded that the voltage signal Vout output by the bridge circuit can well reflect the pressure parameter.
As shown in fig. 5, the conductivity sensor 639 includes an insulating base 6391, four conductivity electrodes 6392 are disposed on the insulating base 6391, and the conductivity sensor 639 is clamped in the pressure ring 633 by the insulating base 6391.
In the present invention, the acquisition of the two inorganic parameters of temperature and conductivity by the temperature sensor 637 and the conductivity sensor 639, respectively, is well known in the art and will not be described in detail here.
In the present invention, the circuit board 65 is designed with a processing circuit, which mainly functions to receive temperature, voltage, and actual conductivity data, calculate pressure parameters based on the received voltage signals, calculate other parameters such as exact conductivity, salinity, total dissolved solids, resistivity, and water density based on the pressure, actual conductivity, and the like, and transmit these parameters to the outside, and in addition, the circuit board 65 is responsible for supplying power (low voltage) to the sensor core 63. The wiring board 65 and the processing circuitry thereon are well known in the art and will not be described in detail herein.
Based on the underground water multi-inorganic parameter online detection system, the invention also provides an underground water multi-inorganic parameter online detection method, which comprises the following steps:
1) sleeping;
2) the CPU control circuit 32 determines whether or not a sampling command issued remotely is received by means of the remote communication device 40: if yes, entering 3), otherwise, returning to 1);
3) judging the authenticity of the sampling command: if true, entering 4), otherwise returning to 1);
4) the CPU control circuit 32 controls the drainage port 54 to be closed through the electromagnetic valve 58, and then the water pump control circuit 33 controls the first relay K1 and the second relay K2 to be switched on to start the sampling pump 20, so that the water sample flows into the water sample flow cell 50 from the water sample inlet 53, and the water sample flow cell 50 starts to collect the water sample;
5) the CPU control circuit 32 is used to start the water quality detection sensor 60, the sampling frequency of the water quality detection sensor 60 can be set according to the water yield of the sampling pump 20, and can be set to 1 minute/time generally;
6) whether the water quality detection sensor 60 itself is soaked in the water sample of the water sample flow cell 50 is judged based on the pressure signal detected by the water quality detection sensor 60: if the water sample is soaked, entering 7), otherwise, repeatedly executing 6);
7) the water quality detection sensor 60 detects the actual conductivity at intervals according to a set sampling frequency, and judges whether the water sample is stable based on the multiple actual conductivities detected at intervals: if the water sample is stable, entering 8), otherwise, repeatedly executing 7);
8) the water quality detection sensor 60 detects three inorganic parameters of temperature, pressure and actual conductivity at intervals of a set sampling frequency, and calculates other inorganic parameters based on the detected temperature, pressure and actual conductivity, wherein: the other inorganic parameters may be any one or more of water level, exact conductivity, salinity, total dissolved solids, resistivity or water density;
9) the water quality detection sensor 60 stores all obtained inorganic parameter data and feeds the data back to the CPU control circuit 32, and the CPU control circuit 32 sends the data to a remote center by the remote communication device 40;
10) the remote center issues a sampling stopping command, finishes, namely stops the water quality detection sensor 60 by means of the CPU control circuit 32, stops the sampling pump 20 by controlling the first relay K1 and the second relay K2 to be turned off by the water pump control circuit 33, and controls the drain port 54 to be opened by the solenoid valve 58 to drain off the water sample, and returns to 1).
In practical implementation, the sampling of the authenticity of the command can be realized by, for example, determining the last character of the command string, which is a conventional technology and is not limited.
In actual practice, depending on the position of the water quality sensor 60 installed in the second flow-through chamber 52, it is generally assumed that the water quality sensor 60 is immersed in the sampled water when the water level in the second flow-through chamber 52 calculated based on the pressure signal is 0.5 m or more. In other words, the water level data can be calculated based on the pressure data detected by the water quality detection sensor 60.
In actual practice, the water quality detecting sensor 60 calculates inorganic parameters of water level, exact conductivity, salinity, total dissolved solids, resistivity and water density based on the detected temperature, pressure and actual conductivity data, which are well known in the art, so the specific calculation process is not described in detail herein.
In view of the defects of large limitation, low efficiency, large error, time and labor waste and the like of the real situation of the water sample judged by the field sampling usually depending on the experience of workers, the water sample stability judgment method with strong universality, high efficiency, small error, time and labor saving is adopted in the method, the real situation of the water sample is determined by the water sample stability judgment method depending on the stability situation of the actual detected actual conductivity, and the efficiency and the quality of the field water sample collection are greatly improved. Preferably, in step 7), it is determined whether three actual conductivities detected by the water quality sensor 60 at intervals and continuously satisfy that Δ actual conductivity is less than or equal to ± 3%, where Δ actual conductivity is an average of the three actual conductivities: and if so, considering the water sample to be stable, otherwise, considering the water sample to be unstable.
Because the water quality detection sensor 60 needs to be placed in the water sample flow cell 50 for long-term detection, and the water level of the water quality detection sensor 60 is not higher than 1 meter, the water quality detection sensor 60 needs to perform error zeroing treatment for a small range of detection requirements, and the water quality detection sensor 60 can bring zero drift errors due to long-term outdoor operation, the water quality detection sensor 60 used in the invention adopts a zero drift compensation method to eliminate the errors and ensure the detection precision, specifically:
the water quality detection sensor 60 adopts the following zero drift compensation method when detecting each inorganic parameter data of temperature, pressure and actual conductivity, and comprises the following steps:
A) determining a correct detection zero point, wherein the detection zero point is the detection starting time:
a-1) acquiring M discrete data before and after starting to detect the inorganic parameter data, and removing the maximum value ymaxAnd the minimum value yminThen, the average μ y is obtained by the following equation 1) for the remaining M-2 discrete data:
in formula 1):
i is 1, 2, …, M is a positive integer greater than 2, but y (i) ≠ ymaxAnd y (i) ≠ ymin，
For M discrete data y (1), y (2), … …, y (M) collected before the start of the detection of the inorganic parameter data, a pre-detection mean value μ y1 is obtained based on equation 1),
obtaining a mean value μ y2 after detection based on formula 1 for M discrete data y (1), y (2), … …, y (M) collected after the start of the detection of the inorganic parameter data;
a-2) the sampling variance y is found based on the following equation 2):
in formula 2):
i is 1, 2, …, M is a positive integer greater than 2, but y (i) ≠ ymaxAnd y (i) ≠ ymin，
For the M discrete data y (1), y (2), … …, y (M) collected before the start of the detection of the inorganic parameter data, the maximum value y is removedmaxAnd the minimum value yminThen, the pre-detection sampling variance y1 is obtained based on equation 2),
for the M discrete data y (1), y (2), … …, y (M) collected after the start of the detection of the inorganic parameter data, the maximum value y is removedmaxAnd the minimum value yminThen, obtaining a post-detection sampling variance y2 based on the formula 2);
a-3) setting threshold 1 to make the following judgment:
judging whether the difference between the pre-detection sampling variance y1 and the pre-detection mean value mu y1 is larger than 1: if yes, the detection zero point does not meet the detection requirement at the moment, the detection zero point is not the correct detection zero point, and A-1) -A-3 are repeatedly executed after a new detection zero point is selected again, otherwise, the next step is carried out;
judging whether the difference between the post-detection sampling variance y2 and the post-detection mean value mu y2 is greater than 1: if so, indicating that the detection zero point at the moment does not meet the detection requirement and is not the correct detection zero point, reselecting a new detection zero point and then repeatedly executing A-1) -A-3), otherwise, considering the detection zero point at the moment as the correct detection zero point;
B) judging the type of zero drift:
b-1) average 12 of the difference between μ y1 and μ y2 was obtained based on the following formula 3):
b-2) setting a threshold value 2 to judge as follows:
for the post-detection mean μ y2, determine if 12/μ y2 is less than 2: if so, determining that baseline zero drift occurs after the detection of the inorganic parameter data is started, otherwise, determining that slope zero drift occurs after the detection of the inorganic parameter data is started;
C) correction compensation is performed for different types of zero drift:
for baseline zero drift, correction compensation is performed based on the following equation 4):
y(i)′＝y(i)-μy12 4)
in formula 4):
y (i) is N discrete data collected from the detection of the inorganic parameter data starting from the correct zero point of detection, i is 0, 1, 2, …, N-1, N is a positive integer greater than 2,
y (i)' is a correction value obtained by correcting and compensating y (i);
for the slope zero drift, correction compensation is performed based on the following equation 5):
y(i)′＝y(i)-[k×y(i+1)×T+μy1]5)
in formula 5):
t is the inorganic parameter data acquisition period, k is a given slope,
y (i) is N discrete data collected from the detection of the inorganic parameter data starting from the correct zero point of detection, i is 0, 1, 2, …, N-1, N is a positive integer greater than 2, N is the number of discrete data collected,
y (i)' is a correction value obtained by correcting and compensating y (i).
In the zero drift compensation method, the inorganic parameter data refers to one of temperature, pressure and actual conductivity, in other words, the zero drift compensation method is used to correct the compensation error when detecting temperature, pressure and actual conductivity, so as to improve the detection precision.
In actual detection, the zero drift is generally divided into baseline zero drift and slope zero drift.
The invention has the advantages that:
the system is installed in the field, the detection of the inorganic parameters of the underground water is transferred from a laboratory to the field for on-line detection, various inorganic parameters of the underground water can be timely and automatically sampled and detected without the need of personnel on duty, the time and labor are saved, the detection efficiency is high, the truth of the sample is high, the directivity of the detection result is good, the scientific research utilization rate is high, the obtained data samples are multiple, the data is continuous, accurate and reliable, the data can be timely stored, the arrangement is convenient, and the system can be widely applied to engineering such as hydrogeological investigation, regional water pollution quality investigation, polluted site restoration and the like.
The method has the function of judging the stability of the water sample on one hand, and adopts zero drift compensation during data acquisition on the other hand, so that the truth of the sample is ensured, and the accuracy and the reliability of the acquired data are improved.
The above description is of the preferred embodiment of the present invention and the technical principles applied thereto, and it will be apparent to those skilled in the art that any changes and modifications based on the equivalent changes and simple substitutions of the technical solutions of the present invention are within the protection scope of the present invention without departing from the spirit and scope of the present invention.
Claims (10)
1. The utility model provides a many inorganic parameters of groundwater on-line measuring system which characterized in that: it includes intelligent control appearance, water quality testing sensor and water sample flow-through cell, wherein: the intelligent control instrument comprises a CPU control circuit, the CPU control circuit synchronously controls the connection and disconnection of a first relay and a second relay through a water pump control circuit, so that the power-on starting and the power-off stopping of the sampling pump are controlled through the first relay and the second relay; the water sample outlet of the sampling pump is connected with the water sample inlet installed at the top of the water sample flow cell, the drain outlet is installed at the bottom of the water sample flow cell, the CPU control circuit controls the opening and closing of the drain outlet through the electromagnetic valve, the water quality detection sensor is installed in the water sample flow cell, and the water quality detection sensor is connected with the CPU control circuit.
2. The groundwater multi-inorganic parameter online detection system according to claim 1, characterized in that:
the intelligent control instrument comprises a power supply circuit, wherein the power supply circuit comprises a voltage conversion circuit and a voltage stabilizing circuit, the input end of the voltage conversion circuit is connected with 220V alternating current, and the output end of the voltage conversion circuit is connected with the power supply ends of the CPU control circuit and the water pump control circuit through the voltage stabilizing circuit to provide power.
3. The groundwater multi-inorganic parameter online detection system according to claim 1, characterized in that:
the water pump control circuit comprises an optical coupler, the CPU control circuit is connected with the input side of the optical coupler, the isolation output side of the optical coupler is connected with coils of the first relay and the second relay through a triode control circuit, moving contacts of the first relay and the second relay are both connected with 220V alternating current, and normally open fixed contacts are respectively connected with a zero line input port and a live line input port of the sampling pump, wherein: the first relay and the second relay are in normally open states; the triode control circuit comprises an NPN type triode and a control resistor, the control resistor is connected with coils of the first relay and the second relay in parallel and then connected to a collector of the NPN type triode, and a base of the NPN type triode is connected with the isolation output side of the optocoupler.
4. The groundwater multi-inorganic parameter online detection system according to claim 1, characterized in that:
the water sample flow-through tank is a closed tank body, a first flow-through chamber and a second flow-through chamber which are not communicated with each other in bottom isolation and top communication are divided by an isolation plate in the water sample flow-through tank, a water sample inlet is positioned above the first flow-through chamber, a drainage opening is respectively arranged below the first flow-through chamber and the second flow-through chamber, a water quality detection sensor is arranged at the lower part of the second flow-through chamber, and an overflow opening is arranged at the upper part of the water sample flow-through tank.
5. The groundwater multi-inorganic parameter online detection system according to claim 4, characterized in that:
the water sample flow-through cell is installed large-traffic sample connection and micro-flow sample connection, and wherein, the honeycomb duct of upwards perk is connected on the micro-flow sample connection, installs filter equipment in the honeycomb duct, and the export of honeycomb duct is higher than the water sample entry.
6. The groundwater multi-inorganic parameter online detection system according to claim 1, characterized in that:
the water quality detection sensor comprises a sensor cylinder, a sensor core body is clamped in an inner cavity of the sensor cylinder, a bottom opening of the sensor cylinder is sealed through head blockage, a circuit board cylinder is installed at a top opening of the sensor cylinder, a circuit board is installed in the inner cavity of the circuit board cylinder, a male connector is installed at the top opening of the circuit board cylinder, a female connector is connected to the top of the male connector through a male connector and a female connector fixing nut, a four-pin plug fixing sleeve used for fixing four-pin plugs is arranged on the male connector and the female connector in a penetrating mode, a tail pressing cap is installed on the top opening of the female connector, a lead led out from the sensor core body is connected with a signal input port of the circuit board, and the lead led out from a signal output port of the circuit board sequentially penetrates through the male connector, the female connector and the tail pressing cap through a detection cable.
7. The groundwater multi-inorganic parameter online detection system according to claim 6, wherein:
the sensor core comprises a main shell, an oil filling cavity is arranged at the top of the main shell, the oil filling cavity extends downwards to be communicated with an upper groove formed in the bottom of the main shell, a silicon diaphragm of a pressure measuring circuit is etched by laser light at the bottom of the upper groove, a temperature measuring element is arranged on the surface of the silicon diaphragm facing the oil filling cavity, the oil filling cavity is sealed by a sealing cover after being filled with silicon oil, a corrugated sheet is fixed at the bottom of the main shell through an annular compression ring, a gap is kept between the corrugated sheet and the silicon diaphragm and filled with the silicon oil, a conductivity sensor is arranged in the compression ring and located below the corrugated sheet, and a lead led out from the pressure measuring circuit and the temperature measuring element penetrates through the silicon oil in, and the lead led out from the conductivity sensor penetrates through the pressure ring and a through hole formed in the main shell and then is connected with the output pin interface, and the output pin interface is connected with a signal input port of the circuit board.
8. An online detection method for multiple inorganic parameters of underground water based on the online detection system for multiple inorganic parameters of underground water of any one of claims 1 to 7, characterized by comprising the following steps:
1) sleeping;
2) judging whether a sampling command issued remotely is received: if yes, entering 3), otherwise, returning to 1);
3) judging the authenticity of the sampling command: if true, entering 4), otherwise returning to 1);
4) the electromagnetic valve is used for controlling the drainage port to be closed, then the water pump control circuit is used for controlling the first relay and the second relay to be conducted so as to start the sampling pump, and the water sample flow cell starts to collect water samples;
5) starting the water quality detection sensor;
6) whether the water quality detection sensor is soaked in a water sample or not is judged based on the pressure signal detected by the water quality detection sensor: if the water sample is soaked, entering 7), otherwise, repeatedly executing 6);
7) the water quality detection sensor detects actual conductivity at intervals and judges whether a water sample is stable or not based on multiple times of actual conductivity detected at intervals: if the water sample is stable, entering 8), otherwise, repeatedly executing 7);
8) the water quality detection sensor detects temperature, pressure and actual conductivity at intervals, and calculates other inorganic parameters;
9) the water quality detection sensor stores all obtained inorganic parameter data and sends the data to a remote center;
10) the remote center issues a sampling stopping command, finishes and returns to 1).
9. The groundwater multi-inorganic parameter online detection method according to claim 8, characterized in that:
in the step 7), it is determined whether or not three actual conductivities alternately and continuously detected by the water quality detection sensor satisfy that Δ actual conductivity is less than or equal to ± 3%: and if so, considering the water sample to be stable, otherwise, considering the water sample to be unstable.
10. The groundwater multi-inorganic parameter online detection method according to claim 8, characterized in that:
the water quality detection sensor adopts a zero drift compensation method when detecting each inorganic parameter data of temperature, pressure and actual conductivity, and the zero drift compensation method comprises the following steps:
A) determination of the correct detection zero:
a-1) acquiring M discrete data before and after starting to detect the inorganic parameter data, and removing the maximum value ymaxAnd the minimum value yminThen, the average μ y is obtained by the following equation 1) for the remaining M-2 discrete data:
in formula 1):
i is 1, 2, …, M is a positive integer greater than 2, but y (i) ≠ ymaxAnd y (i) ≠ ymin，
For M discrete data y (1), y (2), … …, y (M) collected before the start of the detection of the inorganic parameter data, a pre-detection mean value μ y1 is obtained based on equation 1),
obtaining a mean value μ y2 after detection based on formula 1 for M discrete data y (1), y (2), … …, y (M) collected after the start of the detection of the inorganic parameter data;
a-2) the sampling variance y is found based on the following equation 2):
in formula 2):
i is 1, 2, …, M is a positive integer greater than 2, but y (i) ≠ ymaxAnd y (i) ≠ ymin，
For the M discrete data y (1), y (2), … …, y (M) collected before the start of the detection of the inorganic parameter data, the maximum value y is removedmaxAnd the minimum value yminThen, the pre-detection sampling variance y1 is obtained based on equation 2),
for the M discrete data y (1), y (2), … …, y (M) collected after the start of the detection of the inorganic parameter data, the maximum value y is removedmaxAnd the minimum value yminThen, obtaining a post-detection sampling variance y2 based on the formula 2);
a-3) setting threshold 1 to make the following judgment:
judging whether the difference between the pre-detection sampling variance y1 and the pre-detection mean value mu y1 is larger than 1: if yes, the detection zero point is not the correct detection zero point, a new detection zero point is selected again, and then A-1) -A-3) are executed repeatedly, otherwise, the next step is executed;
judging whether the difference between the post-detection sampling variance y2 and the post-detection mean value mu y2 is greater than 1: if so, indicating that the current detection zero point is not the correct detection zero point, reselecting a new detection zero point and then repeatedly executing A-1) -A-3), otherwise, considering the current detection zero point as the correct detection zero point;
B) judging the type of zero drift:
b-1) average 12 of the difference between μ y1 and μ y2 was obtained based on the following formula 3):
b-2) setting a threshold value 2 to judge as follows:
for the post-detection mean μ y2, determine if 12/μ y2 is less than 2: if so, determining that baseline zero drift occurs after the detection of the inorganic parameter data is started, otherwise, determining that slope zero drift occurs after the detection of the inorganic parameter data is started;
C) correction compensation is performed for different types of zero drift:
for baseline zero drift, correction compensation is performed based on the following equation 4):
y(i)′＝y(i)-μy12 4)
in formula 4):
y (i) is N discrete data collected from the detection of the inorganic parameter data starting from the correct zero point of detection, i is 0, 1, 2, …, N-1, N is a positive integer greater than 2,
y (i)' is a correction value obtained by correcting and compensating y (i);
for the slope zero drift, correction compensation is performed based on the following equation 5):
y(i)′＝y(i)-[k×y(i+1)×T+μy1]5)
in formula 5):
t is the inorganic parameter data acquisition period, k is a given slope,
y (i) is N discrete data collected from the detection of the inorganic parameter data starting from the correct zero point of detection, i is 0, 1, 2, …, N-1, N is a positive integer greater than 2,
y (i)' is a correction value obtained by correcting and compensating y (i).
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| CN117147974B (en) * | 2023-10-19 | 2024-05-10 | 北京江云智能科技有限公司 | Underground water collecting and quality analyzing device with integrated temperature, water level and conductivity |
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