A formation pressure sensor based on graphene

Abstract

The present invention relates to a formation pressure sensor based on graphene, comprising: a shell, two force measuring structures are symmetrically arranged in the shell, one of which is arranged on the inner top surface of the shell, and the other is arranged on the inner bottom surface of the shell, the force measuring structure comprises a deformation transmission rod connected to the inner top surface or the inner bottom surface of the shell, an elastic membrane horizontally arranged between the inner walls of the shell, the elastic membrane is in contact with the end of the deformation transmission rod, a graphene film is arranged on the side of the elastic membrane away from the end of the deformation transmission rod, and an electrode is arranged on the side of the graphene film away from the elastic membrane; electrical signal transmission structures are arranged at both ends of the elastic membrane, the electrical signal transmission structures are connected to the electrodes through wires, and also include a groove, which is opened at the bottom of the shell; a soil-retaining and water-permeable structure is arranged in the groove to prevent fine particles of the formation soil from entering the groove to squeeze the bottom of the shell. The device can adjust the measurement range and resolution of the sensor, can detect the total water and soil pressure and the pore water pressure at the same time, and is worthy of promotion.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a graphene-based formation pressure sensor. Background Art

[0002] Pressure sensors are commonly used in industrial practice. They are widely used in various industrial automatic control environments, involving water conservancy and hydropower, railway transportation, intelligent buildings, production automatic control, aerospace, military industry, petrochemicals, oil wells, electricity, ships, machine tools, pipelines and many other industries. In the field of geotechnical and underground engineering, formation pressure is a very important design, construction, and operation and maintenance parameter. Among them, the most concerned are the total water and soil pressure and pore water pressure of the formation. By measuring both at the same time, the effective stress of the formation soil skeleton can be obtained, and then the key information such as the consolidation state and strength level of the soil can be judged.

[0003] In the prior art, although pressure can be measured, there is no pressure sensor that can measure the total water and soil pressure of the formation and the pore water pressure at the same time. Summary of the invention

[0004] The purpose of the present invention is to provide a graphene-based formation pressure sensor, because the existing sensors cannot achieve flexible adjustment of the sensor range and minimum resolution, and cannot measure the total water and soil pressure and pore water pressure of the formation at the same time.

[0005] The technical solution of the present invention is: a formation pressure sensor based on graphene, comprising:

[0006] case;

[0007] Two force measuring structures are symmetrically arranged on the inner top surface and the inner bottom surface of the shell along the center of the shell, including:

[0008] A deformation transmission rod, one end of which is correspondingly connected to the inner top surface or the inner bottom surface of the shell;

[0009] The elastic membrane is horizontally arranged between the inner walls of the shell, and one side of the elastic membrane is in contact with the end of the deformation transmission rod which is away from the inner top surface or the inner bottom surface;

[0010] The graphene film is arranged on a side of the elastic film away from the end of the deformation transmission rod;

[0011] An electrode is arranged on a side of the graphene film facing away from the elastic film;

[0012] The electrical signal transmission structure is made of conductive material and connected between the two opposite ends of the elastic membrane and the inner wall of the shell, and connected to the electrodes through wires;

[0013] Also includes a groove, which is provided at the bottom of the shell;

[0014] The soil-retaining and water-permeable structure is arranged in the groove to prevent fine particles of the stratum soil from entering the groove and squeezing the bottom of the shell under the stratum pressure.

[0015] Preferably, the electrical signal transmission structure includes a fixed rod, one end of which is connected to the inner wall of the shell, and the other end of the fixed rod is connected to the elastic membrane, wherein one end of the fixed rod facing away from the elastic membrane passes through the side wall of the shell and extends outside the shell, and an adjustment structure is provided on the extended section of the fixed rod, and the adjustment structure is used to adjust the stretching rate of the elastic membrane and the graphene film.

[0016] Preferably, the adjustment structure includes a section of thread provided on a fixing rod passing through the housing and a nut sleeved on the fixing rod.

[0017] Preferably, the elastic film, the fixing rod and the graphene film are all bonded by epoxy resin, and the graphene film and the electrode are also bonded by epoxy resin.

[0018] Preferably, the nut is provided with scales.

[0019] Preferably, the soil-retaining and water-permeable structure comprises a plate body fixed in the groove, and the plate body is provided with a plurality of pore channels for allowing pore water in the formation to pass through and preventing formation soil particles from passing through.

[0020] Beneficial effects of the present invention:

[0021] 1. The graphene-based formation pressure sensor provided by the present invention can be used on a large scale.

[0022] 2. The present invention provides a graphene-based formation pressure sensor, which can change the measurement range and resolution of the device by adjusting the structure.

[0023] 3. The present invention provides a graphene-based formation pressure sensor, which transfers the surface deformation caused by the total water and soil pressure and pore water pressure in the formation to the graphene film through a deformation transfer rod. The total water and soil pressure and pore water pressure in the formation can be measured simultaneously through the electrodes on the graphene film. It can also be used for pressure measurement in conventional pressure sensor application scenarios and is worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A cross-sectional view of the overall structure of the present invention;

[0025] Figure 2 It is a three-dimensional diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1 To the attached Figure 2 , a specific embodiment of the present invention is described in detail, but it should be understood that the protection scope of the present invention is not limited by the specific embodiment.

[0027] Example 1

[0028] The embodiment of the present invention provides a formation pressure sensor based on graphene, such as Figure 1 As shown, it includes: a shell 1, in which two force measuring structures are symmetrically arranged along the center of the shell 1, one of which is arranged on the inner top surface of the shell 1, and the other is arranged on the inner bottom surface of the shell 1.

[0029] Among them, the force measuring structure includes: one end of which is correspondingly connected to the deformation transmission rod 8 on the inner top surface or inner bottom surface of the shell 1, and an elastic membrane 7 is horizontally arranged between the inner walls of the shell 1, one side of the elastic membrane 7 is in contact with the end of the deformation transmission rod 8 away from the inner top surface or inner bottom surface, and the side of the elastic membrane 7 away from the end of the deformation transmission rod 8 is provided with a graphene film 6, and the side of the graphene film 6 away from the elastic membrane 7 is provided with an electrode 5; the opposite two ends of the elastic membrane 7 are provided with an electric signal transmission structure, the electric signal transmission structure is connected between the end of the elastic membrane 7 and the inner wall of the shell 1, the electric signal transmission structure is made of conductive material, one end of the electric signal transmission structure is connected to the electrode 5 through a wire, and the other end of the electric signal transmission structure is connected to the reading device to form a loop.

[0030] It also includes a groove, which is opened at the bottom of the shell 1; a soil-retaining and water-permeable structure 4, which is arranged in the groove to prevent fine particles of the stratum soil from entering the groove and squeezing the bottom of the shell 1 under the stratum pressure.

[0031] Example 2

[0032] On the basis of Example 1, Figure 2 The electrical signal transmission structure includes a fixed rod 2, one end of which is connected to the inner wall of the shell 1, and the other end of the fixed rod 2 is connected to the elastic membrane 7, wherein one end of the fixed rod 2 facing away from the elastic membrane 7 passes through the side wall of the shell 1 and extends outside the shell 1. In order to determine the relationship between the pressure exerted on the pressure sensor and the sensing data under different stretching rates and adjust the measurement range and resolution of the device, an adjustment structure is arranged on the extension section of the fixed rod 2, and the adjustment structure is used to adjust the stretching rate of the elastic membrane 7 and the graphene film 6.

[0033] The adjustment structure includes a section of thread provided on a fixing rod 2 passing through the housing 1 and a nut 3 sleeved on the fixing rod 2 .

[0034] In order to ensure stable connection between the elastic membrane 7 and the fixed rod 2 and the graphene film 6, the elastic membrane 7 and the fixed rod 2 and the graphene film 6 are bonded by epoxy resin, and the graphene film 6 and the electrode 5 are also bonded by epoxy resin.

[0035] In order to accurately adjust the stretching rate of the elastic film 7 and the graphene film 6 , a scale is provided on the nut 3 .

[0036] Furthermore, in order to prevent the formation soil particles from affecting the measurement of the formation pore water pressure, the retaining and permeable structure 4 includes a plate body fixed in the groove, and the plate body is provided with a plurality of pore channels for the formation pore water to pass through and prevent the formation soil particles from passing through.

[0037] Among them, the hole connects the measuring stratum outside the groove and the pressure measuring area inside the groove. The size of the hole is smaller than the particle size of the measuring stratum soil, ensuring that the pore water of the stratum passes through and enters the pressure measuring area inside the groove without the soil entering, thereby isolating the soil pressure of the stratum and enabling the pressure measuring area inside the groove to measure the pore water pressure of the stratum.

[0038] How it works

[0039] When the device is in use, the top and bottom surfaces of the sensor bend inward due to the pressure from the outside, and the deformation is transmitted to the elastic film through the deformation transmission rod, which eventually causes the graphene film 6 to bend and deform. The deformation of the graphene film 6 causes the electrical properties such as resistivity to change. When the power is on, the pressure sensor can measure the pressure by measuring the electrical characteristic parameters of the graphene film under different outside pressures.

[0040] First, one end of the wire is used to connect the two fixed rods 2, and the other end is connected to the reading device to take readings of the sensors at both ends of the instrument. The wire connected to the fixed rods 2 of the same graphene film 6 can obtain a set of data. By turning the dial, the movable rod 4 is moved, thereby adjusting the stretching rate of the elastic membrane 7 and the graphene film 6, so that the electrical parameters of the bending deformation micro-strain resistivity change value of the graphene film with different stretching rates are different, and then the corresponding pressure measurement range and resolution are different, so as to adjust the sensor range and minimum resolution. Through the calibration test, the relationship between the pressure on the pressure sensor and the sensing data under different stretching rates of the graphene film 6 is obtained, and the calibration work is completed.

[0041] Under different stretching rates of the graphene film 6, the relationship between the loaded pressure P and the collected data (X) is obtained through experiments. P=f(X). The pressure P1 is loaded on the sensor, and the indication received by the voltage amplifying and measuring device in the circuit is X1. The indication is substituted into P=f(X) to obtain the specific pressure value P1=f(X1), thereby obtaining the pressure, that is, the pressure is measured.

[0042] During specific work, the range and minimum resolution of the sensor are determined according to the estimated range of the total soil and water pressure value and the pore water pressure value of the application scenario, the dial is rotated to correspond, the reading wire is connected, and the device is placed in the measurement stratum. The pressure measured on the top surface is the total soil and water pressure of the stratum, and the pressure measured on the bottom surface (on the side with the retaining and permeable structure 3) is the pore water pressure.

[0043] To sum up, the graphene-based formation pressure sensor provided in the embodiment of the present invention can change the measurement range and resolution of the device by adjusting the structure; the total water and soil pressure and the pore water pressure in the formation are transmitted to the graphene film through the deformable transmission rod, and the total water and soil pressure and the pore water pressure in the formation can be measured simultaneously through the electrodes on the graphene film. It can also be used for pressure measurement in conventional pressure sensor application scenarios, and is worthy of promotion.

[0044] The above disclosures are only several specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A graphene-based formation pressure sensor, characterized in that: include: Housing (1); Two force measuring structures are symmetrically arranged on the inner top surface and inner bottom surface of the shell (1) along the center of the shell (1), and include: A deformation transmission rod (8), one end of which is correspondingly connected to the inner top surface or the inner bottom surface of the shell (1); An elastic membrane (7) is horizontally arranged between the inner walls of the housing (1), and one surface of the elastic membrane is in contact with the end of the deformation transmission rod (8) that is away from the inner top surface or the inner bottom surface; The graphene film (6) is arranged on a side of the elastic film (7) that is away from the end of the deformation transmission rod (8); the electrode (5) is arranged on a side of the graphene film (6) that is away from the elastic film (7); An electrical signal transmission structure is made of a conductive material and connected between two opposite ends of an elastic membrane (7) and an inner wall of a shell (1), and is connected to an electrode (5) via a wire; the electrical signal transmission structure comprises a fixing rod (2), one end of the fixing rod (2) is connected to the inner wall of the shell (1), and the other end of the fixing rod (2) is connected to the elastic membrane (7), one end of one of the fixing rods (2) facing away from the elastic membrane (7) passes through the side wall of the shell (1) and extends outside the shell (1), and an adjustment structure is provided on the extension section of the fixing rod (2), and the adjustment structure is used to adjust the stretching rate of the elastic membrane (7) and the graphene film (6); It also includes a groove, which is formed at the bottom of the housing (1); The soil-retaining and water-permeable structure (4) is arranged in the groove to prevent fine particles of the stratum soil from entering the groove and squeezing the bottom of the shell (1) under stratum pressure; the soil-retaining and water-permeable structure (4) comprises a plate body fixed in the groove, and the plate body is provided with a plurality of pore channels for the passage of stratum pore water and preventing the passage of stratum soil particles.

2. A graphene-based formation pressure sensor according to claim 1, characterized in that: The adjustment structure comprises a section of thread arranged on a fixing rod (2) passing through the housing (1) and a nut (3) sleeved on the fixing rod (2).

3. A graphene-based formation pressure sensor as claimed in claim 2, characterized in that: The elastic film (7), the fixing rod (2) and the graphene film (6) are all bonded together by epoxy resin, and the graphene film (6) and the electrode (5) are also bonded together by epoxy resin.

4. A graphene-based formation pressure sensor as claimed in claim 2, characterized in that: The nut (3) is provided with a scale.

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