CN107045006B - Device for detecting oil gas pollution of underground water by using very low frequency method - Google Patents

Abstract

The invention discloses a device for detecting oil and gas pollution of underground water by a very low frequency method, which comprises a box body and a control panel arranged in the box body, wherein the control panel is provided with a whip antenna, a magnetic rod antenna, a USB interface, a display, an LED alarm lamp, a frequency range selection button and a power switch, a built-in circuit of the control panel comprises an electromagnetic induction field receiving unit, a signal processing unit and a power supply unit, and the power supply unit is respectively connected with the electromagnetic induction field receiving unit and the signal processing unit through circuits. The invention has simple structure, low cost and convenient use, analyzes through the amplitude and the phase of the very low frequency signal, avoids the technical problem that the signal of only one navigation station can be received at one time by only utilizing the amplitude information of the signal in the prior art, so that the error of the measurement result is large, and effectively improves the detection efficiency and the detection precision.

Description

Device for detecting oil and gas pollution in groundwater by very low frequency method

technical field

The invention belongs to the technical field of detection devices for oil and gas pollution in ground water, and in particular relates to a device for detecting oil and gas pollution in ground water with a very low frequency method.

Background technique

Today, our country has entered the era of automobiles, and more and more people drive private cars. Many car owners often have trouble finding gas stations. However, when gas stations are built in front of their own homes, people can't help but worry about whether the gas stations are safe. Gas stations are one of the sources of urban pollution that cannot be ignored. It is understood that there are not many oil and gas leakage incidents at gas stations in various places. For example, in a survey in the United States in the 1990s, 40% of the 210,000 gas stations had leaks, and 150,000 gas stations were waiting to be dealt with. Leaked oil and gas will pollute groundwater sources and soil, bringing unpredictable risks to people's comfortable urban life. However, in the past, in order to eliminate pollution and prevent the further spread of pollution, people usually drilled several wells near the oil and gas leakage and took groundwater samples for analysis. energy. Therefore, it is imperative to develop a groundwater oil and gas pollution detection device with flexible working methods and high measurement accuracy. In addition, the development of high-precision underground oil and gas pollution detection technology is also the cornerstone of building a safe and green city in the era of science and technology.

Contents of the invention

The technical problem solved by the present invention is to provide a device for detecting oil and gas pollution in groundwater with a flexible working method and high measurement accuracy. , so that the staff can grasp the oil and gas pollution status of groundwater in a certain area in real time.

In order to solve the above technical problems, the present invention adopts the following technical scheme. The device for detecting oil and gas pollution in groundwater by the very low frequency method is characterized in that it includes a box body and a control panel arranged inside the box body. The control panel is provided with a whip antenna and a magnetic rod. Antenna, USB interface, display, LED alarm light, frequency band selection button and power switch, the built-in circuit of the control panel includes an electromagnetic induction field receiving unit, a signal processing unit and a power supply unit, wherein the power supply unit passes the line and the electromagnetic induction field receiving unit and signal The processing unit is connected; the electromagnetic induction field receiving unit includes an anti-aliasing filter, a low-noise amplifier, a rubidium atomic frequency standard and a pulse shaping circuit, and the whip antenna and the magnetic rod antenna are respectively electrically connected to the anti-aliasing filter. The antenna is used to receive the 10-15KHz VLF signal from the navigation station. The magnetic rod antenna is made of magnetically permeable material to induce electromagnetic signals around the magnetic rod. The anti-aliasing filter is electrically connected to the low-noise amplifier. The anti-aliasing filter is used to filter the received electromagnetic signal and extract the useful electromagnetic signal. The low-noise amplifier is electrically connected with the A/D acquisition card. The low-noise amplifier is composed of AD7520 with adjustable gain. Amplifying circuit, the magnification can be adjusted within 8-128, which can amplify useful signals according to the strength of the received signal. The rubidium atomic frequency standard is electrically connected to the pulse shaping circuit. The rubidium atomic frequency standard is used to output a stable sine wave signal. The pulse shaping circuit is electrically connected with the A/D acquisition card, and the pulse shaping circuit is used to process the sine wave signal and output a 40KHz sampling pulse signal; the signal processing unit includes the A/D acquisition card and computer, and the A/D acquisition card It is electrically connected with the computer. The A/D acquisition card is used to convert the amplified useful signal and the sampling pulse signal and store them in the A/D acquisition card. The computer has a built-in apparent resistivity calculation module. The apparent resistivity The calculation module is used to calculate and process the data in the A/D acquisition card to obtain the apparent resistivity of the area, and compare it with the standard value of the apparent resistivity of clean groundwater stored in the computer. It is connected with the display, and the LED alarm light is used to start an alarm reminder when the relative value of the measured apparent resistivity exceeds the upper limit of the set value. The display is used to display all the data during the test, which is stored in the data storage module of the computer and Export via USB interface for data research.

The operation method of the device for detecting groundwater oil and gas pollution by the very low frequency method of the present invention is characterized in that the specific process is: when it is necessary to detect whether the oil and gas leakage near the gas station pollutes the nearby groundwater and the degree and scope of the pollution, the leakage at the gas station The point is the center of the circle, with any length as the radius, place the detection device horizontally on the ground parallel to the surface, turn on the power switch, the power supply equipment starts to work, the whip antenna automatically searches for the VLF signal emitted by the Russian Alpha navigation system, and the magnetic rod antenna starts to sense For the magnetic field component in the vertical direction, rotate the channel selection knob at the same time, fix the knob after the signal is stable, extract the useful signal through the anti-aliasing filter, and amplify it through the low-noise amplifier, and then combine it with the frequency division circuit of the rubidium atomic frequency standard The 40KHz sampling pulse signal output by shaping is converted and processed in the A/D acquisition card. The computer processes and records the amplitude and phase of the extracted VLF signal, and calculates the relative change in apparent resistivity. After comparison and analysis, the final The data result is transmitted to the data storage module of the computer, and displayed on the display, if the data result exceeds the set upper limit, the LED warning light starts to alarm.

The invention is simple in structure, low in cost and easy to use, and analyzes the amplitude and phase of the very low frequency signal, avoiding the prior art that only uses the amplitude information of the signal, and can only receive the signal of one navigation station at a time, so that the error of the measurement result is large The technical problems have effectively improved the detection efficiency and detection accuracy.

Description of drawings

Fig. 1 is a module connection diagram of the present invention;

Fig. 2 is a structural schematic diagram of the present invention.

In the figure: 1. Cabinet, 2. Control panel, 3. Whip antenna, 4. Magnetic rod antenna, 5. USB interface, 6. Frequency band selection button, 7. Display, 8. Power switch, 9. LED warning light .

Detailed ways

The specific content of the present invention will be described in detail in conjunction with the accompanying drawings. As shown in Figure 1-2, the device for detecting oil and gas pollution in groundwater by the very low frequency method includes a box body 1 and a control panel 2 installed inside the box body 1. The control panel 2 is equipped with a whip antenna 3 and a magnetic rod antenna 4 , USB interface 5, display 7, LED alarm light 9, frequency band selection button 6 and power switch 8, the built-in circuit of control panel 2 includes electromagnetic induction field receiving unit, signal processing unit and power supply unit, wherein the power supply unit is connected with electromagnetic induction by circuit respectively The field receiving unit is connected to the signal processing unit; the electromagnetic induction field receiving unit includes an anti-aliasing filter, a low-noise amplifier, a rubidium atomic frequency standard and a pulse shaping circuit, and the whip antenna 3 and the magnetic rod antenna 4 are respectively connected with the anti-aliasing filter Electrically connected, the whip antenna 3 is used to receive VLF signals from the navigation station with a band of 10-15KHz, the magnetic rod antenna 4 is made of magnetically conductive material for inductive electromagnetic signals around the magnetic rod, anti-aliasing filtering The device is electrically connected with the low noise amplifier, the anti-aliasing filter is used to filter the received electromagnetic signal and extract useful electromagnetic signals, the low noise amplifier is electrically connected with the A/D acquisition card, the low noise amplifier The gain-adjustable amplification circuit composed of AD7520 is adopted, and the amplification factor can be adjusted within 8-128. It can amplify useful signals according to the strength of the received signal. The rubidium atomic frequency standard is electrically connected with the pulse shaping circuit. The rubidium atomic frequency standard It is used to output a stable sine wave signal. The pulse shaping circuit is electrically connected to the A/D acquisition card. The pulse shaping circuit is used to process the sine wave signal and output a 40KHz sampling pulse signal; the signal processing unit includes A/D acquisition card and computer, the A/D acquisition card is electrically connected with the computer, the A/D acquisition card is used to convert and process the amplified useful signal and sampling pulse signal and store it in the A/D acquisition card, and the computer has a built-in video Resistivity calculation module, the apparent resistivity calculation module is used to calculate and process the data in the A/D acquisition card to obtain the apparent resistivity of the area, and compare it with the standard value of apparent resistivity of clean groundwater stored in the computer , the computer is respectively connected to the LED alarm light and the display through the line, the LED alarm light is used to start an alarm when the relative value of the measured apparent resistivity exceeds the upper limit of the set value, and the display is used to display all the data in the test process, the data Stored in the data storage module of the computer and exported through the USB interface for data research.

The working principle of the present invention is: when the groundwater is polluted by oil and gas, the resistivity in the polluted area is mainly controlled by the gasoline above the water table, and the gasoline infiltrates the soil above the water table, causing the resistivity to rise. In addition, the polluted area The clay on the surface forms a good containment layer, preventing the free diffusion of gasoline. By measuring the relative change value of the groundwater resistivity and comparing these changes with the real resistivity value of the groundwater after signal processing, the oil and gas pollution of the groundwater here can be inferred. The invention uses the amplitude of the very low frequency signal The analysis with the phase avoids the technical problem of only using the amplitude information of the signal in the prior art, and only accepting the signal of one navigation station at a time, which causes a large error in the measurement result, and effectively improves the detection efficiency and detection accuracy.

The specific operation process of the present invention is: when it is necessary to detect whether the oil and gas leakage near the gas station pollutes the nearby groundwater and the degree and scope of the pollution, the leakage point of the gas station is used as the center of the circle, and any length is used as the radius. device, turn on the power switch, the power supply equipment starts to work, and then the whip antenna automatically searches for the VLF signal from the Russian Alpha navigation system, the magnetic rod antenna starts to sense the magnetic field component in the vertical direction, and at the same time rotate the channel selection knob until the signal is stable Fixed knob, the useful signal is extracted by the anti-aliasing filter, amplified by the low-noise amplifier, and converted in the A/D acquisition card with the 40KHz sampling pulse signal output by the rubidium atomic frequency standard frequency division circuit Processing, the computer processes and records the amplitude and phase of the extracted VLF signal, and calculates the relative change in apparent resistivity. After comparison and analysis, the data result is finally transmitted to the data storage module of the computer and displayed on the display. , if the data result exceeds the set upper limit, the LED alarm light will start to alarm. The device can be used by relevant staff to understand the oil and gas pollution of groundwater in the area in real time, and then formulate a reasonable treatment plan based on the test results to improve the environment and ensure the quality of life of nearby residents.

The basic principles, main features and advantages of the present invention have been shown and described above. On the premise of not departing from the spirit and scope of the present invention, the present invention also has various changes and improvements, and these changes and improvements all fall into the claimed invention. range.

Claims (1)

1. A method of operation of a device for detecting oil-gas pollution in groundwater by a very low frequency method, characterized in that: the device for detecting oil-gas pollution in groundwater by the very low frequency method includes a casing and a control panel that is arranged on the inside of the casing, and the control panel is equipped with There are whip antenna, magnetic rod antenna, USB interface, display, LED alarm light, frequency band selection button and power switch, and the built-in circuit of the control panel includes electromagnetic induction field receiving unit, signal processing unit and power supply unit, in which the power supply unit is connected to the The electromagnetic induction field receiving unit is connected to the signal processing unit; the electromagnetic induction field receiving unit includes an anti-aliasing filter, a low-noise amplifier, a rubidium atomic frequency standard and a pulse shaping circuit, and the whip antenna and the magnetic rod antenna are respectively connected with the anti-aliasing filter Electrically connected, the whip antenna is used to receive VLF signals with a band of 10-15KHz from the navigation station. The magnetic rod antenna is made of magnetically conductive material to induce electromagnetic signals around the magnetic rod. The anti-aliasing filter and The low-noise amplifier is electrically connected, and the anti-aliasing filter is used to filter the received electromagnetic signal and extract useful electromagnetic signals. The low-noise amplifier is electrically connected to the A/D acquisition card. The low-noise amplifier uses a gain The adjustable amplifying circuit composed of AD7520, the magnification can be adjusted within 8-128, can amplify the useful signal according to the strength of the received signal, the rubidium atomic frequency standard is electrically connected with the pulse shaping circuit, the rubidium atomic frequency standard is used for Output a stable sine wave signal, the pulse shaping circuit is electrically connected with the A/D acquisition card, the pulse shaping circuit is used to process the sine wave signal and output a 40KHz sampling pulse signal; the signal processing unit includes the A/D acquisition card and The computer, the A/D acquisition card is electrically connected with the computer. The A/D acquisition card is used to convert the amplified useful signal and the sampling pulse signal and store it in the A/D acquisition card. The computer has built-in apparent resistivity Calculation module, the apparent resistivity calculation module is used to calculate and process the data in the A/D acquisition card to obtain the apparent resistivity of the area, and compare it with the standard value of apparent resistivity of clean groundwater stored in the computer. Connect with the LED alarm light and the display through the line. The LED alarm light is used to start an alarm when the relative value of the measured apparent resistivity exceeds the upper limit of the set value. The display is used to display all the data during the test, which is stored in the computer. In the data storage module and exported through the USB interface to facilitate data research; The specific operation process of the device for detecting oil and gas pollution in groundwater by the very low frequency method is as follows: when it is necessary to detect whether the oil and gas leakage near the gas station pollutes the nearby groundwater and the degree and scope of the pollution, take the leakage point of the gas station as the center of the circle and take any length as Radius, place the detection device horizontally at a place parallel to the ground surface, turn on the power switch, the power supply equipment starts to work, the whip antenna automatically searches for the VLF signal from the Russian Alpha navigation system, and the magnetic rod antenna starts to sense the magnetic field component in the vertical direction, and at the same time Rotate the channel selection knob, fix the knob after the signal is stable, extract the useful signal through the anti-aliasing filter, amplify it through the low-noise amplifier, and combine it with the 40KHz sampling pulse signal output by the rubidium atomic frequency standard frequency division circuit The conversion process is carried out in the A/D acquisition card, and the computer processes and records the amplitude and phase of the extracted VLF signal, and calculates the relative change in apparent resistivity. After comparison and analysis, the data result is finally transmitted to the computer. In the storage module and displayed on the display, if the data result exceeds the set upper limit, the LED alarm light will start to alarm.

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