阅读说明：本技术 一种基于声表面波的土壤VOCs检测装置 (Soil VOCs detection device based on surface acoustic wave ) 是由 袁林 杨俊光 于 2020-12-15 设计创作，主要内容包括：本发明公开了一种基于声表面波的土壤VOCs检测装置,检测钻头上设有第一加热机构,检测钻头内设有检测腔,所述检测腔侧壁设有气体入口,所述检测腔内设有检测半透膜,声表面波传感器用于通过探测检测半透膜的声表面波探测进入所述检测腔的VOCs气体。通过上述优化设计的基于声表面波的土壤VOCs检测装置,利用检测半透膜对VOCs气体的选择性溶解渗透,通过声表面波传感器对检测半透膜接触VOCs气体时的声表面波进行探测,实现对VOCs气体的检测,从而实现土壤中VOCs气体的原位定量检测,提高检测精度和灵敏度。(The invention discloses a soil VOCs detection device based on surface acoustic waves.A first heating mechanism is arranged on a detection drill bit, a detection cavity is arranged in the detection drill bit, a gas inlet is formed in the side wall of the detection cavity, a detection semipermeable membrane is arranged in the detection cavity, and a surface acoustic wave sensor is used for detecting VOCs gas entering the detection cavity through the surface acoustic waves for detecting the detection semipermeable membrane. Through the soil VOCs detection device based on surface acoustic wave of above-mentioned optimal design, utilize and detect the pellicle and to the gaseous selective dissolution infiltration of VOCs, detect the surface acoustic wave when detecting the pellicle contact VOCs gas through the surface acoustic wave sensor, realize the gaseous detection to VOCs to realize the gaseous normal position quantitative determination of VOCs in the soil, improve detection precision and sensitivity.)

1. The utility model provides a soil VOCs detection device based on surface acoustic wave which characterized in that includes: detecting a drill bit (1) and a surface acoustic wave sensor;

be equipped with first heating mechanism on detecting drill bit (1), be equipped with in detecting drill bit (1) and detect chamber (3), it is equipped with gas inlet to detect chamber (3) lateral wall, be equipped with in detecting chamber (3) and detect pellicle (2), the surface acoustic wave sensor is used for detecting the surface acoustic wave that detects pellicle (2) through surveying and gets into the VOCs gas of detecting chamber (3).

2. Surface acoustic wave based detection apparatus of VOCs in soil according to claim 1, characterized in that the gas inlet is provided with an inlet semi-permeable membrane (4);

preferably, the gas inlet is provided with an inlet valve (5).

3. Surface acoustic wave-based detection apparatus for soil VOCs according to claim 2, characterized in that the first heating means is connected to the inlet semi-permeable membrane (4) for heating the inlet semi-permeable membrane (4).

4. A surface acoustic wave-based detection device for VOCs in soil according to claim 1, wherein the side wall of the detection cavity (3) is further provided with a gas outlet;

preferably, the gas outlet is provided with an outlet valve (6);

preferably, the gas outlet is provided with an outlet semi-permeable membrane (7).

5. Surface acoustic wave-based detection apparatus of VOCs in soil according to claim 1, characterized in that a plurality of detection chambers (3) arranged side by side are provided in the detection bit (1).

6. A device for detecting VOCs (volatile organic compounds) in soil based on Surface Acoustic Wave (SAW) according to claim 1, wherein the detection cavity (3) comprises a main cavity (11) and at least one secondary cavity (12), a main detection semipermeable membrane (21) and a main SAW sensor used for detecting the main detection semipermeable membrane (21) are arranged in the main cavity (11), the secondary cavity (12) is located on one side of the main cavity (11) far away from a gas inlet and is communicated with the main cavity (11) through a secondary gas inlet, the direction of the main cavity (11) is inwards kept away from in the secondary cavity (12) and is sequentially provided with a secondary detection semipermeable membrane (22) and a secondary SAW sensor used for detecting the secondary detection semipermeable membrane (22).

7. A surface acoustic wave-based detection device for soil VOCs according to claim 6, wherein a secondary air inlet valve (31) is further arranged in the secondary chamber (12), and the secondary air inlet valve (31) is positioned on one side of the secondary detection semipermeable membrane (22) close to the main chamber (11).

8. A surface acoustic wave-based detection device for soil VOCs (volatile organic chemicals) in accordance with claim 6, wherein a secondary air-intake semi-permeable membrane (32) is further disposed in the secondary chamber (12), and the secondary air-intake semi-permeable membrane (32) is located on the side of the secondary detection semi-permeable membrane (22) close to the main chamber (11).

9. A surface acoustic wave-based detection device for VOCs in soil according to claim 8, further comprising a second heating mechanism connected to the secondary air-intake semi-permeable membrane (32) for heating the secondary air-intake semi-permeable membrane (32).

10. Surface acoustic wave-based soil VOCs detection apparatus as claimed in claim 8, wherein the second-stage detection semi-permeable membrane (22) of the plurality of second-stage chambers (12) is a different VOCs semi-permeable membrane, and the second-stage air intake semi-permeable membrane (32) and the second-stage detection semi-permeable membrane (22) in each second-stage chamber (12) are the same VOCs semi-permeable membrane.

Technical Field

The invention relates to the technical field of soil VOCs detection, in particular to a soil VOCs detection device based on surface acoustic waves.

Background

The pollutants in the land not only comprise heavy metals such as mercury, chromium, lead, cadmium, arsenic and nickel, but also can contain organic matters such as benzene series, chlorinated hydrocarbons, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, pesticides and polychlorinated biphenyl, and inorganic matters such as cyanide and corrosive ions. The raw materials, intermediates, catalysts or end products of the production process can contaminate the land. Due to long-term industrial activities, land pollution is mostly characterized by organic and inorganic composite pollution.

Common volatile organic pollutants harmful to human health include volatile halogenated hydrocarbons, benzene series, chlorobenzene series, and the like. Therefore, the detection of volatile organic compounds in soil plays an important role in pollution control. With the use of large quantities of pesticides, organic solvents and the discharge of large quantities of waste water and waste products, the serious contamination of soils, sediments, surface and ground water sources and ecosystems with volatile organic pollutants (VOCs) has become a ubiquitous environmental problem.

Volatile organic compounds are various organic compounds having a boiling point of 50 to 260 ℃ at normal temperature. After the VOCs enter the soil and underground water system, the growth of crops can be influenced, vegetation can be damaged, and the health of people is seriously harmed. The main reason is that the quantity and speed of VOCs entering the soil exceed the capacity and purification speed of the soil, so that the properties, composition, properties and the like of the soil are changed, and the accumulation process of pollutants is gradually dominant. Therefore, detection of Volatile Organic Compounds (VOCs) in soil plays an important role in pollution control.

Currently, analysis of VOCs includes both laboratory instrumental analysis and field instrumental detection. VOCs has very easily volatilizees and the characteristics that run off, consequently, although laboratory instrument analysis can be to VOCs accuracy nature determination and ration, but the sample will pass through a plurality of intermediate links such as transportation, save, greatly increased the volatile possibility of sample, the analysis result lacks the promptness, and the cost is on the high side, needs research and development on-the-spot VOCs real-time quick analysis device.

Since the gas content in the deep soil environment is low, the gas moving path is long, and the VOCs gas cannot be pumped to the ground by adopting a negative pressure direct pumping mode, a Membrane Interface Probe (MIP) system is widely applied in recent years. The permeable membrane is an important component of the MIP system, and in the process of passing the VOCs gas through the permeable membrane, firstly, the VOCs gas molecules are dissolved on the surface of the membrane in contact with the membrane, then, due to concentration gradients on two sides of the membrane, the VOCs gas molecules are diffused to the other side of the membrane, and finally, the VOCs gas molecules are resolved from the other side surface of the membrane. Then, the carrier gas is utilized to take away the VOCs gas molecules, and the continuous detection of the concentration of the volatile organic pollutants at different depths in the soil can be realized by combining with the detection and analysis equipment for the volatile organic compounds on the ground, so that the detection of the VOCs in the soil can be realized. However, after the detection needs to collect the VOCs gas, the VOCs gas is carried to the ground through the carrier gas, so that the loss of the VOCs gas in the conveying process is caused, the detection precision is greatly reduced, and therefore, the detection can only carry out qualitative detection on the VOCs, but cannot realize quantitative detection.

Surface acoustic wave sensors are widely used sensing devices in recent years. The method and the device measure the parameters to be measured on the surface of the object through the disturbance of physical and chemical yields to the acoustic wave propagation characteristics, and have the advantages of wide detection object, wide application range, high sensitivity, quick response, small volume, low cost, recyclability and the like.

Disclosure of Invention

In order to solve the technical problems in the background technology, the invention provides a soil VOCs detection device based on surface acoustic waves.

The invention provides a soil VOCs detection device based on surface acoustic waves, which comprises: detecting a drill bit and an acoustic surface wave sensor;

detect to be equipped with first heating mechanism on the drill bit, be equipped with in the detection drill bit and detect the chamber, it is equipped with gas inlet to detect the chamber lateral wall, it is equipped with the detection pellicle to detect the intracavity, and the surface acoustic wave sensor is used for detecting the surface acoustic wave that detects the pellicle and gets into detect the VOCs gas in chamber.

Preferably, the gas inlet is provided with an inlet semi-permeable membrane;

preferably, the gas inlet is provided with an inlet valve.

Preferably, the first heating means is connected to the inlet semipermeable membrane for heating the inlet semipermeable membrane.

Preferably, the side wall of the detection cavity is also provided with a gas outlet;

preferably, an outlet valve is arranged at the gas outlet;

preferably, the gas outlet is provided with an outlet semi-permeable membrane.

Preferably, a plurality of detection cavities arranged side by side are arranged in the detection drill bit.

Preferably, it includes main cavity and at least one second grade cavity to detect the chamber, is equipped with the main surface acoustic wave sensor who detects the pellicle and be used for detecting the main surface acoustic wave that detects the pellicle in the main cavity, and the second grade cavity is located the main cavity and keeps away from gas inlet one side and communicates with the main cavity through the second grade air inlet, keep away from to the interior direction of main cavity is equipped with the second grade in proper order and detects the pellicle and is used for detecting the second grade surface acoustic wave sensor that detects the pellicle.

Preferably, still be equipped with the second grade valve of admitting air in the second grade cavity, the second grade valve of admitting air is located second grade and detects pellicle and be close to main cavity one side.

Preferably, still be equipped with the second grade in the second grade cavity and admit air the pellicle, the second grade is admitted air the pellicle and is located the second grade and detect pellicle and be close to main cavity one side.

Preferably, the secondary air inlet semi-permeable membrane is connected with a secondary air inlet semi-permeable membrane through a second heating mechanism.

Preferably, the second-stage detection semipermeable membranes of the multiple second-stage chambers are different VOCs semipermeable membranes, and the second-stage air inlet semipermeable membrane and the second-stage detection semipermeable membrane in each second-stage chamber are the same type of VOCs semipermeable membrane.

According to the soil VOCs detection device based on the surface acoustic wave, a first heating mechanism is arranged on a detection drill bit, a detection cavity is arranged in the detection drill bit, a gas inlet is formed in the side wall of the detection cavity, a detection semipermeable membrane is arranged in the detection cavity, and a surface acoustic wave sensor is used for detecting VOCs gas entering the detection cavity through the surface acoustic wave for detecting the detection semipermeable membrane. Through the soil VOCs detection device based on surface acoustic wave of above-mentioned optimal design, utilize and detect the pellicle and to the gaseous selective dissolution infiltration of VOCs, detect the surface acoustic wave when detecting the pellicle contact VOCs gas through the surface acoustic wave sensor, realize the gaseous detection to VOCs to realize the gaseous normal position quantitative determination of VOCs in the soil, improve detection precision and sensitivity.

Drawings

Fig. 1 is a schematic structural diagram of a soil VOCs detection device based on surface acoustic waves according to the present invention.

Fig. 2 is a schematic diagram of a detection cavity layout of another embodiment of the surface acoustic wave-based soil VOCs detection apparatus according to the present invention.

Fig. 3 is a schematic layout diagram of a detection cavity of a soil VOCs detection apparatus based on surface acoustic waves according to still another embodiment of the present invention.

Detailed Description

As shown in fig. 1 to 3, fig. 1 is a schematic structural diagram of a surface acoustic wave-based soil VOCs detection device, fig. 2 is a schematic layout diagram of a detection chamber of another embodiment of the surface acoustic wave-based soil VOCs detection device, and fig. 3 is a schematic layout diagram of a detection chamber of another embodiment of the surface acoustic wave-based soil VOCs detection device.

Referring to fig. 1, the soil VOCs detection device based on surface acoustic waves provided by the invention comprises: detecting the drill bit 1 and the surface acoustic wave sensor;

detect to be equipped with first heating mechanism on the drill bit 1, be equipped with in the detection drill bit 1 and detect chamber 3, it is equipped with gas inlet to detect 3 lateral walls in chamber, it detects pellicle 2 to be equipped with in the detection chamber 3, and the surface acoustic wave sensor is used for detecting the surface acoustic wave that detects pellicle 2 through surveying and gets into detect the VOCs gas in chamber 3.

In the concrete working process of the soil VOCs detection device based on the surface acoustic wave, VOCs in soil around the probe body are evaporated to form VOCs gas under the heating of the first heating mechanism, VOCs gas molecules are contacted with the membrane by utilizing the dissolving and diffusing mechanism of the semipermeable membrane and then dissolved on the surface of the membrane, so that the surface acoustic wave of the semipermeable membrane is changed, and the surface acoustic wave sensor is used for qualitatively and quantitatively detecting the VOCs gas by detecting the change on the semipermeable membrane; because the detection semipermeable membrane both sides surface produces concentration gradient, make gaseous molecule diffuse to membrane opposite side, from the analytic of membrane opposite side surface at last, realize the selective permeation to VOCs gas.

In this embodiment, the soil VOCs detection device based on surface acoustic wave that provides detects and is equipped with first heating mechanism on the drill bit, is equipped with in the detection drill bit and detects the chamber, it is equipped with gas inlet to detect the chamber lateral wall, it is equipped with the detection pellicle to detect the intracavity, and surface acoustic wave sensor is used for detecting the surface acoustic wave through surveying the detection pellicle and gets into detect the VOCs gas in chamber. Through the soil VOCs detection device based on surface acoustic wave of above-mentioned optimal design, utilize and detect the pellicle and to the gaseous selective dissolution infiltration of VOCs, detect the surface acoustic wave when detecting the pellicle contact VOCs gas through the surface acoustic wave sensor, realize the gaseous detection to VOCs to realize the gaseous normal position quantitative determination of VOCs in the soil, improve detection precision and sensitivity.

In particular implementation, gas entrance is equipped with entry pellicle 4 for only VOCs is gaseous can pass entry pellicle and detection pellicle contact, and then avoids other gaseous influence to the surface acoustic wave that detects the pellicle, further improves and detects the precision.

Further, gas inlet is equipped with inlet valve 5, descends the in-process at the drill bit for detect the chamber and close, avoid the gaseous entering of the interior VOCs of non-detection soil layer, can protect the detection pellicle simultaneously.

In other embodiments who detect the chamber, detect 3 lateral walls in chamber and still be equipped with gas outlet, detect the chamber and form logical cavity structure, detect pellicle both sides pressure balance, guarantee the gaseous molecule of VOCs and detect the stable flow of intracavity, and then improve the accuracy that surface acoustic wave sensor detected.

Further, gas outlet is equipped with export pellicle 7, avoids other gaseous through gas outlet back diffusion in the soil to advance to detect the chamber, causes the influence to detecting the pellicle surface.

In addition, gas outlet is equipped with outlet valve 6, can protect the export pellicle on the one hand, and on the other hand forms the gaseous collection cavity of VOCs between detection pellicle and outlet valve through closing outlet valve, takes out the gas of gathering along with the drill bit, carries out further detection.

Referring to fig. 2, in another specific embodiment of this embodiment, a plurality of detection cavities 3 arranged side by side are provided in the detection drill bit 1, and the detection semipermeable membranes in the detection cavities can be designed to be dedicated to different types of pollutants, so that each detection cavity can only enter one type of pollutant gas, thereby realizing accurate detection of the type and the proportion of the pollutant gas.

Referring to fig. 3, in another embodiment of this embodiment, the detection cavity 3 includes a main cavity 11 and at least one secondary cavity 12, the main detection semipermeable membrane 21 and the main surface acoustic wave sensor for detecting the main detection semipermeable membrane 21 are disposed in the main cavity 11, the secondary cavity 12 is located on a side of the main cavity 11 away from the gas inlet and is communicated with the main cavity 11 through a secondary gas inlet, and the secondary detection semipermeable membrane 22 and the secondary surface acoustic wave sensor for detecting the secondary detection semipermeable membrane 22 are sequentially disposed in the secondary cavity 12 towards a direction away from the main cavity 11; specifically, the secondary detection semi-permeable membranes 22 of the multiple secondary chambers 12 are semi-permeable membranes of different VOCs.

In the specific working process of the embodiment, the surrounding soil is heated by the first heating mechanism, so that VOCs gas formed by evaporation in the soil enters the main chamber, dissolved on the surface of the main detection semi-permeable membrane, the surface acoustic wave change of the main detection semi-permeable membrane 21 caused by VOCs gas is detected by the main surface acoustic wave sensor, when the main surface acoustic wave sensor detects that the surface acoustic wave changes, the situation that VOCs exist in soil is indicated, VOCs gas is separated out from one side of the main detection semi-permeable membrane close to the secondary cavity, different types of VOCs are dissolved on the corresponding secondary air inlet semi-permeable membrane again respectively, when a certain secondary surface acoustic wave detects the surface acoustic wave change of the corresponding secondary detection semipermeable membrane, the soil contains VOC corresponding to the secondary detection semipermeable membrane, thereby realizing the quantitative and accurate detection of the VOC, and finally discharging the VOCs gas after the VOCs gas passes through the second-stage detection semipermeable membrane; in this embodiment, make the gaseous enrichment in the main cavity of VOCs through mainly detecting the pellicle for the indoor gas concentration of main cavity increases, then the gaseous further second that detects the pellicle surface at the second grade of VOCs dissolves, thereby improves VOCs's gaseous detectivity and detection precision greatly.

In order to avoid the gaseous pellicle influence each other of detecting the second grade of the detection of different VOCs, still be equipped with the second grade in the second grade cavity 12 and admit air pellicle 32, the second grade admits air pellicle 32 and is located the second grade and detects pellicle 22 and be close to 11 one sides of main cavity, specifically, the second grade in every second grade cavity 12 admits air pellicle 32 and the second grade detects pellicle 22 and be the same kind of VOCs pellicle, make with the gaseous unable second grade cavity that gets into of other VOCs that the second grade cavity is unmatched, and then improve the detection.

In other specific embodiments of this embodiment, a secondary air inlet valve 31 is further disposed in the secondary chamber 12, and the secondary air inlet valve 31 is located on the side of the secondary detection semi-permeable membrane 22 close to the main chamber 11.

In the specific heating process of the heating mechanism, the first heating mechanism is connected with the inlet semipermeable membrane 4 and is used for heating the inlet semipermeable membrane 4; soil direct heating around through the pellicle for the VOCs gas of the evaporation of being heated in the soil around directly gets into the pressure measurement cavity via the pellicle, improves heating efficiency and the gaseous sampling efficiency of VOCs.

Correspondingly, still include second heating mechanism, second heating mechanism and second grade admit air pellicle 32 and be connected and be used for the second grade pellicle 32 that admits air and heat, keep warm to the interior VOCs gas of main cavity, guarantee that it further passes the second grade pellicle of admitting air, avoid the main cavity to remain to improve the detection precision that the second grade detected.

Similarly, can also design third heating mechanism and second grade pellicle 41 of giving vent to anger, third heating mechanism and second grade pellicle 41 of giving vent to anger are connected and are used for giving vent to anger pellicle 41 to the second grade and heat, keep warm to the gaseous VOCs in the second grade cavity, guarantee that it passes the second grade pellicle discharge of giving vent to anger, avoid remaining in the second grade cavity.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.