Intelligent micro-pressure measuring system

Abstract

The intelligent micro-pressure measuring system can accurately and rapidly measure the height difference of liquid columns on the two sides of a U-shaped pipe pressure gauge through an industrial camera and an image recognition system and convert the height difference into a pressure signal so as to continuously and accurately measure the micro-pressure difference in a pipeline in a high-precision mode, and comprises an aluminum profile frame used for supporting and fixing the whole structure, all the components are installed; the U-shaped pipe pressure meter and the U-shaped pipe pressure pipe are connected to a measured pipeline system to indirectly measure the pipeline micro-pressure; the spiral lead screw is driven by a stepping motor, the lead screw is provided with a sliding block, the sliding block is connected with the camera support through a bolt, and the sliding block is controlled by the motor to move up and down; the industrial camera module is installed on the moving sliding block, the camera module comprises an industrial camera, a lens, a light source, a micrometer, a camera support and the like, and the sliding block drives the camera module to move; and the image recognition system is used for analyzing and recognizing picture pixels and analyzing the height difference between the liquid level height and the scale of the U-shaped tube pressure gauge through the application relation.

Description

Technical Field

[0001] The invention belongs to the technical field of pressure detection, and in particular relates to an intelligent micro-pressure measuring system. Background Art

[0002] Pressure is one of the key parameters of the pipeline system. The accurate measurement of micro pressure is extremely important for process control and product quality. The general way to measure micro pressure is to first convert the pressure signal into an intermediate signal, and then convert the intermediate signal into an electrical signal to output the pressure value. Existing micro pressure sensors usually use silicon piezoresistive elements to detect changes in medium pressure. The pressure change causes the diaphragm to produce a small displacement, thereby changing the line resistance. By detecting this change, a standard signal corresponding to this pressure is converted and output. There are problems such as limited installation, easy damage, and low accuracy. In particular, the detection and optimization of small pressure changes in pipelines needs further research.

[0003] Technical problems existing in existing technologies:

[0004] In fluid transportation or some other fields, pipelines are often needed to transport fluids. In pipeline transportation, pressure is one of the most important parameters. In order to accurately measure the medium pressure in the pipeline, micro-pressure sensors are often installed in the pipeline.

[0005] Traditional micro-pressure sensors use silicon film as detection elements, which have problems such as limited installation, easy damage, low accuracy, and susceptibility to interference.

[0006] The present invention is compared with the prior art as follows:

[0007] Technical comparison with patent CN103217252A_A mobile container type high-precision micro-pressure detection device

[0008] Method adopted by CN 103217252A:

[0009] Patent CN103217252A proposes a mobile container-type high-precision micro-pressure detection device, which uses a moiré fringe grating ruler and a laser displacement meter to achieve accurate pressure measurement.

[0010] Floats are provided on the liquid surfaces of the movable container and the fixed container, and the floats are provided correspondingly to the laser displacement meters to detect the changes in the liquid surface;

[0011] The actual pressure of the input gas is calculated by the up and down displacement of the movable container, the displacement of the float on the liquid surface in the fixed container and the movable container and the initial position;

[0012] The grating measuring mechanism is used to convert the up and down displacement distance of the movable container into the measurement of the number of moiré fringes, and the photoelectric device is used to realize the electronic subdivision and direction determination function within a moiré fringes to obtain the moving direction and displacement distance of the grating ruler;

[0013] Based on the principle of triangulation, the displacement of the float on the liquid surface in the fixed container and the movable container from the starting position is measured. There is a polytetrafluoro diffuse reflection plane on the top of the float, which projects the reflected light onto the CCD reflector, and the distance between the light spot position on the CCD and the float is calculated by trigonometric function.

[0014] A single-chip microcomputer is used to control a stepper motor to achieve pressure generation and control. Pressure interfaces are provided on both the movable container and the fixed container. The movable container interface is connected to atmospheric pressure, and the fixed container interface is connected to the pressure gauge to be measured and the single-chip microcomputer controller. The controller is connected to a computer system to calculate and display the difference between the pressure to be measured and the actual pressure.

[0015] This method converts the actual pressure of the input gas into the displacement of the float and the starting position of the movable container up and down and the fixed container and the liquid surface in the movable container. The displacement distance is calculated using a striped grating ruler and a laser displacement meter, and the pressure is generated and controlled using a single-chip microcomputer controller, thereby keeping the pressure within a very small fluctuation range for a long time. However, the up and down displacement of the movable container is controlled by manual input, which makes it difficult to achieve automation and continuity of micro-pressure measurement; when using a float to measure the liquid surface displacement, if the liquid density changes, the volume immersed in the float will also change, thus affecting the accuracy of the liquid surface height measurement; at the same time, the float mechanism needs to be regularly maintained and calibrated to ensure the measurement accuracy, which will increase the cost of use and maintenance workload.

[0016] The method of the present invention:

[0017] The present invention uses a combination of hardware and software such as a U-tube pressure gauge, a high-resolution camera, and an image recognition program to identify the height difference of the liquid column on both sides of the U-tube, and then accurately and quickly measure the micro-pressure of the system to be tested, thereby realizing the automation, continuity, and intelligence of micro-pressure measurement. The core innovations of the method are:

[0018] In order to expand the measurement range and improve the measurement accuracy, a rectangular micrometer is used to measure the liquid level of the U-tube. Its minimum grid value is 0.1mm, which greatly improves the measurement accuracy. An image processing program is used to identify the relationship between image pixels and physical length to achieve automation and intelligent micro-pressure measurement.

[0019] Comparison of technical advantages

[0020] Automation, intelligence and continuity of micro-pressure measurement: The present invention adopts an image processing program to identify the relationship between the minimum grid value of the micrometer and the actual physical length, and automatically, continuously and quickly outputs the micro-pressure measurement value. In comparison, the float measurement method adopted by CN103217252A requires waiting for the liquid level to stabilize, and the height of the movable container needs to be manually input into the controller, which is limited in terms of intelligence, continuity and rapidity of the measurement; and the structure and principle of the present invention are relatively simple and clear, easy to use and maintain, and are superior to CN 103217252 A in terms of use and maintenance costs.

[0021] In summary, the intelligent micro-pressure measurement system proposed in the present invention is superior to CN 103217252 A in terms of rapid and continuous micro-pressure measurement and use and maintenance costs. Summary of the invention

[0022] In view of the shortcomings of the prior art, the present invention realizes an intelligent micro-pressure measurement system which can accurately and quickly measure the micro-pressure difference between two points of the system to be measured by identifying the height difference of the liquid column on both sides of the U-tube through a combination of software and hardware such as a U-tube pressure gauge, a high-resolution camera and an image recognition program.

[0023] To achieve the above object, the technical solution adopted by the present invention is:

[0024] An intelligent micro-pressure measurement system, characterized in that it comprises:

[0025] Aluminum profile frame, used to support and fix the overall structure to form an overall frame;

[0026] A U-tube pressure gauge, which is fixed on an aluminum profile frame and connected to a pipeline system to be measured. The U-tube pressure gauge uses the principle of static pressure to convert pressure into liquid column height and accurately measures the liquid column height, thereby indirectly measuring the pipeline micro-pressure in the pipeline system to be measured;

[0027] A screw slide with a motor, which is fixed on an aluminum profile bracket, comprises a stepper motor and a screw rod, the output shaft of the stepper motor is connected to the screw rod, a motion slide is mounted on the screw rod, and the motion slide is controlled by the stepper motor to realize up and down movement;

[0028] A camera module, comprising a camera bracket, an industrial camera, a camera lens, an annular light source, a rectangular micrometer and a background plate, wherein the moving slide is connected to the camera bracket by bolts, the background plate and the industrial camera are relatively fixed on the camera bracket, the camera lens, the annular light source and the rectangular micrometer are sequentially arranged between the two, the camera lens is installed on the industrial camera, the annular light source and the rectangular micrometer are respectively fixed on the camera bracket, the camera lens is arranged through the annular light source and is directly opposite to the rectangular micrometer, the relative position of the rectangular micrometer in the camera lens field of view is fixed, and the industrial camera amplifies the liquid column liquid level, the scale and the rectangular micrometer images at a preset position and transmits them to an image recognition system;

[0029] The image recognition system is used to analyze and identify picture pixels. The industrial camera is connected to the image recognition system and receives the image data transmitted by it. The correspondence between the pixels and the actual length is calibrated by the scale on the rectangular micrometer, and this relationship is used to analyze the height difference between the liquid column liquid level and the scale of the U-tube pressure gauge, identify the height difference of the liquid columns on both sides, and thus measure the tiny pressure difference in the pipeline.

[0030] As a preferred technical solution of the present invention: the U-tube pressure gauge comprises a U-tube, the U-tube is calibrated with a scale, and both ends of the U-tube are respectively provided with connection ports, and the connection ports at both ends are respectively connected to the measured pipeline system, and the pressure on one side of the pipeline is:

[0031] P=ρgh (1)

[0032] Where h is the height of the liquid column on one side of the U-tube, ρ is the density of the working fluid, and g is the acceleration due to gravity.

[0033] As a preferred technical solution of the present invention: a working fluid is arranged in the U-shaped tube, and the working fluid is one of water, alcohol or mercury. The working fluid in the U-shaped tube is immiscible with the fluid inside the measured pipeline system, and has stable physical properties and known density. When measuring the micro-pressure difference of the measured pipeline system, both ends of the U-shaped tube are connected to the measured pipeline system, and the pressure difference corresponding to the height difference Δh of the liquid columns on both sides of the formula (1) is the micro-pressure difference of the measured pipeline system.

[0034] As a preferred technical solution of the present invention: the screw rod is connected to the output shaft of the stepper motor through a coupling, and the stepper motor is equipped with a power supply and a controller. By controlling the rotation direction, number of rotation steps and rotation speed of the stepper motor rotor, the position of the moving slide on the screw rod is changed, thereby changing the position of the camera module, so that the U-tube liquid level, the scale and the rectangular micrometer can be included in the field of view at the same time.

[0035] As a preferred technical solution of the present invention: limit switches are respectively installed on the upper and lower parts of the screw rod, and the limit switches are connected to the controller. When the moving slide moves to a preset position, the limit switch detects a signal and transmits it to the controller. The controller shuts down the stepper motor and the moving slide stops moving.

[0036] As a preferred technical solution of the present invention: the industrial camera is connected to the image recognition system via HDMI, the camera lens is a variable focus lens, and the horizontal distance between the camera lens and the scale of the U-tube pressure gauge is 7-9 cm.

[0037] As a preferred technical solution of the present invention: the annular light source and the rectangular micrometer are both fixed on the camera bracket by a clamp, and the rectangular micrometer is placed close to the scale of the U-tube pressure gauge.

[0038] As a preferred technical solution of the present invention: the minimum grid value of the rectangular micrometer is 0.1 mm. By calibrating the pixels corresponding to the minimum grid value in the image, the relationship between the physical height and the image pixels is obtained, and this relationship can be used to convert the pressure corresponding to the height of the liquid column.

[0039] As a preferred technical solution of the present invention: the image recognition system includes a calibration mechanism, an adjustment mechanism, an identification mechanism, an output mechanism and a judgment mechanism. The calibration mechanism is used to calibrate the pixels of the received image, X pixels are equal to 0.01mm, the adjustment mechanism is used to adjust the height, the movement speed and the direction, the identification mechanism includes a scale identification mechanism and a liquid level identification mechanism, the scale identification mechanism is used to identify the scale height and output the scale height H, the liquid level identification mechanism is used to identify the pixels corresponding to the difference between the lowest point of the liquid level and the scale height and convert them into the height h, the output mechanism is used to output the liquid level height, the liquid level height H1=H+h, the judgment mechanism is used to determine whether to measure the liquid level heights on both sides, if so, directly output the pressure value, P=ρ*g*ΔH,, where h is the height of the liquid column on one side of the U-tube, ρ is the density of the measured liquid, g is the gravitational acceleration constant, ΔH=H1-H2, if not, then the height, movement speed and direction are readjusted through the adjustment mechanism.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The invention has the advantages of simple structure, firmness and durability, convenient reading and reliable data.

[0042] Using a rectangular micrometer instead of a scale reading can greatly improve measurement accuracy, reduce system error and indication error, and thus more accurately measure the micro pressure difference between two points in the measured pipeline system.

[0043] A stepper motor is installed on the top of the screw rod to convert the rotational motion into the axial linear motion of the camera module and the rectangular micrometer. A controller is used to control the rotation direction and speed of the stepper motor, thereby controlling the position of the camera module and the rectangular micrometer, thereby ensuring that the liquid level is always within the field of view of the camera lens.

[0044] The image recognition system is used to identify the corresponding relationship between pixels and the smallest scale of the micrometer, and this relationship is applied to indirectly measure the height of the liquid column, thus realizing the automation and precision of micro-pressure measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of the present invention;

[0046] Figure 2 It is a schematic diagram of the structure of a screw slide with a motor;

[0047] Figure 3 It is a schematic diagram of the structure of each part of the camera module;

[0048] Figure 4 A schematic diagram of the aluminum profile frame constituting the overall frame;

[0049] Figure 5 This is the operation flow chart of the image recognition system;

[0050] Figure 6 This is a physical diagram of the present invention.

[0051] List of reference numerals:

[0052] 1. Aluminum profile frame; 2. U-tube pressure gauge; 3. Screw slide with motor; 4. Camera module; 5. Stepper motor; 6. Screw; 7. Motion slide; 8. Camera bracket; 9. Industrial camera; 10. Camera lens; 11. Ring light source; 12. Rectangular micrometer; 13. Background board. DETAILED DESCRIPTION

[0053] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Please refer to the instruction manual Figure 1-6 The present invention provides a technical solution: an intelligent micro-pressure measurement system, comprising:

[0055] Aluminum profile frame 1, used to support and fix the overall structure to form an overall frame;

[0056] A U-tube pressure gauge 2 is fixed on the aluminum profile frame 1. The U-tube pressure gauge 2 is connected to the measured pipeline system, and the static pressure principle is applied to convert the pressure into the height of the liquid column and accurately measure the height of the liquid column, so as to indirectly measure the pipeline micro-pressure in the measured pipeline system;

[0057] The screw slide 3 with motor is fixed on the aluminum profile bracket, and includes a stepping motor 5 and a screw 6. The output shaft of the stepping motor 5 is connected to the screw 6. The screw 6 is provided with a moving slide 7. The moving slide 7 is controlled by the stepping motor 5 to realize up and down movement.

[0058] The camera module 4 includes a camera bracket 8, an industrial camera 9, a camera lens 10, an annular light source 11, a rectangular micrometer 12 and a background plate 13. The moving slide 7 is connected to the camera bracket 8 by bolts. The background plate 13 and the industrial camera 9 are relatively fixed on the camera bracket 8. The camera lens 10, the annular light source 11 and the rectangular micrometer 12 are sequentially arranged therebetween. The camera lens 10 is installed on the industrial camera 9. The annular light source 11 and the rectangular micrometer 12 are respectively fixed on the camera bracket 8. The camera lens 10 is arranged through the annular light source 11 and is directly opposite to the rectangular micrometer 12. The relative position of the rectangular micrometer 12 in the field of view of the camera lens 10 is fixed. The industrial camera 9 amplifies the images of the liquid column liquid level, the scale and the rectangular micrometer 12 at a preset position and transmits them to the image recognition system.

[0059] The image recognition system is used to analyze and identify image pixels. The industrial camera 9 is connected to the image recognition system and receives the image data transmitted by it. The correspondence between the pixels and the actual length is calibrated by the scale on the rectangular micrometer 12, and this relationship is used to analyze the height difference between the liquid column liquid level and the scale of the U-tube pressure gauge 2, identify the height difference of the liquid columns on both sides, and thus measure the small pressure difference in the pipeline.

[0060] As a preferred technical solution of the present invention: the U-tube pressure gauge 2 includes a U-tube, the U-tube is marked with a scale, and the two ends of the U-tube are respectively provided with connection ports, and the two end connection ports are respectively connected to the measured pipeline system, and the pressure on one side of the pipeline is:

[0061] P=ρgh (1)

[0062] Where h is the height of the liquid column on one side of the U-tube, ρ is the density of the working fluid, and g is the acceleration due to gravity.

[0063] A working fluid is arranged in the U-shaped tube, and the working fluid is one of water, alcohol or mercury. The working fluid in the U-shaped tube is immiscible with the fluid inside the measured pipeline system, and has stable physical properties and known density. When measuring the micro-pressure difference of the measured pipeline system, both ends of the U-shaped tube are connected to the measured pipeline system, and the pressure difference corresponding to the height difference Δh of the liquid columns on both sides according to formula (1) is the micro-pressure difference of the measured pipeline system.

[0064] The screw rod 6 is connected to the output shaft of the stepper motor 5 through a coupling. The stepper motor 5 is equipped with a power supply and a controller. By controlling the rotation direction, number of rotation steps and rotation speed of the rotor of the stepper motor 5, the position of the moving slide 7 on the screw rod 6 is changed, thereby changing the position of the camera module 4 so that the U-tube liquid level, the scale and the rectangular micrometer 12 can be included in the field of view at the same time.

[0065] The upper and lower parts of the screw rod 6 are respectively installed with limit switches, and the limit switches are connected to the controller. When the moving slide 7 moves to a preset position, the limit switch detects a signal and transmits it to the controller. The controller shuts down the stepper motor 5 and the moving slide 7 stops moving.

[0066] The industrial camera 9 is connected to the image recognition system via HDMI, the camera lens 10 is a variable focus lens, and the horizontal distance between the camera lens 10 and the scale of the U-tube pressure gauge 2 is 7-9 cm.

[0067] The annular light source 11 and the rectangular micrometer 12 are both fixed on the camera bracket 8 by a clamp, and the rectangular micrometer 12 is placed close to the scale of the U-tube pressure gauge 2.

[0068] The minimum grid value of the rectangular micrometer 12 is 0.1 mm. By calibrating the pixels corresponding to the minimum grid value in the image, the relationship between the physical height and the image pixels is obtained, and the pressure corresponding to the height of the liquid column can be converted using this relationship.

[0069] The image recognition system includes a calibration mechanism, an adjustment mechanism, an identification mechanism, an output mechanism and a judgment mechanism. The calibration mechanism is used to calibrate the pixels of the received image, and X pixels are equal to 0.01mm. The adjustment mechanism is used to adjust the height, the movement speed and the direction. The identification mechanism includes a scale identification mechanism and a liquid level identification mechanism. The scale identification mechanism is used to identify the scale height and output the scale height H. The liquid level identification mechanism is used to identify the pixels corresponding to the difference between the lowest point of the liquid level and the scale height and convert them into the height h. The output mechanism is used to output the liquid level height, and the liquid level height H1=H+h. The judgment mechanism is used to determine whether to measure the liquid level heights on both sides. If so, the pressure value is directly output, P=ρ*g*ΔH, where h is the height of the liquid column on one side of the U-tube, ρ is the density of the measured liquid, g is the gravitational acceleration constant, ΔH=H1-H2, and if not, the height, movement speed and direction are readjusted through the adjustment mechanism.

[0070] The intelligent micro-pressure measurement system is based on a U-tube pressure gauge 2. It measures pressure by balancing the measured pressure with the static pressure generated by a liquid column of a certain height according to the principle of fluid statics, converts the pressure into the height of the working liquid column, avoids the use of pressure-sensitive elements, ensures the reliable operation of the device, and achieves the effect of quickly and accurately measuring the micro-pressure of the pipeline system to be measured.

[0071] Furthermore, the intelligent micro-pressure measurement system can select different working fluids according to actual working conditions, commonly using water, ethanol, mercury, etc. After measuring the height of the liquid column, the pressure to be measured can be converted through conditions such as the working fluid density, gravitational acceleration and reference pressure.

[0072] Furthermore, the camera module 4 includes a high-resolution industrial camera 9, a zoomable camera lens 10 and a ring light source 11. The pixels of the high-resolution industrial camera 9 range from 500w to 2000w. Taking a 2000w pixel lens as an example, it divides the frame into 5472x3648 grids, each grid corresponds to a pixel. The higher the pixel, the higher the recognition of the picture details.

[0073] Furthermore, the camera module 4 includes a variable-focus camera lens 10, which determines the camera frame and depth of field. When focusing, only one plane is truly in focus. When it is in a non-focus state, that is, the object plane is before or after the focus plane, and light from a certain point on the object at different angles falls on the image plane, forming a blur circle, called a confusion circle. If the diameter of the confusion circle is smaller than the sensor pixel size, this confusion circle is called an allowable confusion circle. There is a distance in the depth before and after the focus plane, and its image is within the allowable range of the confusion circle. This distance is called the depth of field. In the camera module 4, the shooting distance is relatively close (about 8 cm), the focal length of the camera lens 10 is relatively small (within 50 mm), and the depth of field of the camera lens 10 is controlled within 2 mm, which can simultaneously meet the image acquisition requirements of the rectangular micrometer 12, the liquid level, and the U-tube pressure gauge 2.

[0074] Furthermore, the camera module 4 is equipped with a ring light source 11. The industrial camera 9 and the camera lens 10 pass through the central notch of the ring light source 11 to collect images. The power of the ring light source 11 and the aperture size of the lens simultaneously control the imaging brightness. However, since the aperture size is inversely proportional to the depth of field, the larger the aperture, the shallower the depth of field. In the camera module 4, a higher light source brightness and a smaller aperture size are used to avoid the diffusion circle exceeding the sensor pixel, resulting in unclear collected images and affecting the sensor accuracy.

[0075] Furthermore, the rectangular micrometer 12 used has a total scale length of 50 mm and a minimum grid value of 0.1 mm. If water is used as the working fluid, according to formula (1), the minimum value is 1 Pa. Taking into account the height difference of the liquid columns on both sides of the measurement, after two measurements, the maximum theoretical error is 2 Pa, the effective length of the U-tube is 500 mm, the maximum range is ±5000 Pa, and the error range is 0.4% FS. Common micro-pressure sensors on the market have a maximum range ranging from 100 Pa to 5000 Pa, and an error range of 0.5% FS-1% FS. The present invention is superior to common similar products on the market in terms of measurement range and accuracy, and meets the requirements for accurate and rapid measurement of micro-pressure in the measured pipeline system.

[0076] Furthermore, the rectangular micrometer 12 and the industrial camera 9 module 4 are both mounted on the moving slider through a bracket, and the up and down movement of the slider is controlled by the direction and speed of the rotation of the screw rod 6, and the relative position of the rectangular micrometer 12 in the field of view of the industrial camera 9 is fixed. When collecting images, the moving slider is moved up and down to keep the liquid level of the U-shaped tube within the field of view of the camera lens 10, and the relationship between the pixel and the actual height is calibrated using the grid value of the rectangular micrometer 12, so as to measure the height of the liquid column, and achieve the effect of accurately and quickly measuring the micro pressure of the measured pipeline system.

[0077] Furthermore, in order to realize the automation and continuity of measurement, a stepper motor 5 is installed on the screw rod 6. The screw rod 6 is connected to the stepper motor 5 through a coupling. The stepper motor 5 is equipped with a controller and a power supply. The rotation direction, number of rotation steps and rotation speed of the rotor of the stepper motor 5 can be controlled to change the position of the moving slide, thereby changing the position of the camera lens 10, and the U-tube liquid level, scale and micrometer are included in the field of view at the same time.

[0078] Furthermore, limit switches are installed at the upper and lower parts of the screw rod 6, and the limit switches are connected to the controller of the stepper motor 5. When the moving slide 7 moves to a certain position, the limit switch detects a signal and transmits it to the controller of the stepper motor 5, shutting down the stepper motor 5, thereby stopping the moving slide 7 from moving, and preventing the moving slide 7 from colliding after moving beyond the limit and damaging the instrument.

[0079] Furthermore, the camera module 4 transmits the collected image to the image recognition system in the computer in real time through the HDMI interface. After saving the image, the pixel corresponding to the minimum grid value of 0.1mm on the rectangular micrometer 12 is calibrated through the image analysis system, thereby realizing the conversion between image pixels and actual object length.

[0080] Furthermore, the image recognition system will identify the value of the pressure gauge scale closest to the liquid surface and store this value. Then, it will apply the above-mentioned conversion relationship between pixels and physical length to accurately measure the length of the liquid surface from the nearest scale line, and add it to the stored value to obtain the actual height of the liquid column on one side of the U-shaped tube. Repeat this step on the other side to obtain the height of the liquid column on the other side. The pressure difference corresponding to the difference between the two is the micro-pressure difference of the system to be measured.

[0081] Furthermore, the entire device is installed on a frame composed of aluminum profiles, and the frame is fixed by angle pieces and screws, which is safe, stable and convenient for disassembly and installation.

Claims

1. An intelligent micro-pressure measurement system, characterized in that: include: Aluminum profile frame (1), used to support and fix the overall structure to form an overall frame; A U-tube pressure gauge (2), wherein the U-tube pressure gauge (2) is fixed on the aluminum profile frame (1), and the U-tube pressure gauge (2) is connected to the pipeline system to be measured, and the pressure is converted into the height of the liquid column by applying the principle of static pressure and the height of the liquid column is accurately measured, so as to indirectly measure the pipeline micro-pressure in the pipeline system to be measured; A screw slide (3) with a motor, which is fixed on an aluminum profile bracket, comprises a stepping motor (4) and a screw (6), wherein the output shaft of the stepping motor (4) is connected to the screw (6), and a moving slide (7) is mounted on the screw (6), and the moving slide (7) is controlled by the stepping motor (4) to realize up and down movement; A camera module (4) comprises a camera support (8), an industrial camera (9), a camera lens (10), an annular light source (11), a rectangular micrometer (12) and a background plate (13), wherein the moving slide (7) is connected to the camera support (8) by bolts, the background plate (13) and the industrial camera (9) are relatively fixed on the camera support (8), the camera lens (10), the annular light source (11) and the rectangular micrometer (12) are sequentially arranged therebetween, the camera lens (10) is mounted on the industrial camera (9), the annular light source (11) and the rectangular micrometer (12) are respectively fixed on the camera support (8), the camera lens (10) is arranged through the annular light source (11) and is directly opposite to the rectangular micrometer (12), the relative position of the rectangular micrometer (12) in the field of view of the camera lens (10) is fixed, and the industrial camera (9) amplifies the images of the liquid column liquid surface, the scale and the rectangular micrometer (12) at a preset position and transmits them to an image recognition system; The image recognition system is used to analyze and recognize image pixels. The industrial camera (9) is connected to the image recognition system and receives the image data transmitted by the image recognition system. The corresponding relationship between the pixels and the actual length is calibrated by the scale on the rectangular micrometer (12). This relationship is used to analyze the height difference between the liquid column liquid level and the scale of the U-tube pressure gauge (2), and the height difference of the liquid columns on both sides is identified, thereby measuring the small pressure difference in the pipeline.

2. An intelligent micro-pressure measurement system as claimed in claim 1, characterized in that: The U-tube pressure gauge (2) comprises a U-tube, on which a scale is marked, and two ends of the U-tube are respectively provided with connection ports, which are respectively connected to the measured pipeline system, and the pressure on one side of the pipeline is: P=ρgh (1) Where h is the height of the liquid column on one side of the U-tube, ρ is the density of the working fluid, and g is the acceleration due to gravity.

3. An intelligent micro-pressure measurement system as claimed in claim 2, characterized in that: A working fluid is arranged in the U-shaped tube, and the working fluid is one of water, alcohol or mercury. The working fluid in the U-shaped tube is immiscible with the fluid inside the measured pipeline system, and has stable physical properties and known density. When measuring the micro-pressure difference of the measured pipeline system, both ends of the U-shaped tube are connected to the measured pipeline system, and the pressure difference corresponding to the height difference Δh of the liquid columns on both sides according to formula (1) is the micro-pressure difference of the measured pipeline system.

4. The intelligent micro-pressure measurement system according to claim 1, characterized in that: The screw rod (6) is connected to the output shaft of the stepper motor (4) through a coupling. The stepper motor (4) is equipped with a power supply and a controller. By controlling the rotation direction, number of rotation steps and rotation speed of the rotor of the stepper motor (4), the position of the moving slide (7) on the screw rod (6) is changed, thereby changing the position of the camera module (4) so ​​that the U-tube liquid level, the scale and the rectangular micrometer (12) can be included in the field of view at the same time.

5. An intelligent micro-pressure measurement system as claimed in claim 4, characterized in that: The upper and lower parts of the screw rod (6) are respectively provided with limit switches, and the limit switches are connected to a controller. When the moving slide (7) moves to a preset position, the limit switch detects a signal and transmits it to the controller, and the controller shuts down the stepper motor (4), and the moving slide (7) stops moving.

6. The intelligent micro-pressure measuring system according to claim 1, characterized in that: The industrial camera (9) is connected to the image recognition system via HDMI, the camera lens (10) is a variable focus lens, and the horizontal distance between the camera lens (10) and the scale of the U-tube pressure gauge (2) is 7-9 cm.

7. The intelligent micro-pressure measuring system according to claim 1, characterized in that: The annular light source (11) and the rectangular micrometer (12) are both fixed on the camera bracket (8) via a clamp, and the rectangular micrometer (12) is placed close to the scale of the U-tube pressure gauge (2).

8. The intelligent micro-pressure measuring system according to claim 7, characterized in that: The minimum grid value of the rectangular micrometer (12) is 0.1 mm. By calibrating the pixels corresponding to the minimum grid value in the image, the relationship between the physical height and the image pixels is obtained, and the pressure corresponding to the height of the liquid column can be converted by applying this relationship.

9. The intelligent micro-pressure measuring system according to claim 1, characterized in that: The image recognition system includes a calibration mechanism, an adjustment mechanism, an identification mechanism, an output mechanism and a judgment mechanism. The calibration mechanism is used to calibrate the pixels of the received image, and X pixels are equal to 0.01mm. The adjustment mechanism is used to adjust the height, the movement speed and the direction. The identification mechanism includes a scale identification mechanism and a liquid level identification mechanism. The scale identification mechanism is used to identify the scale height and output the scale height H. The liquid level identification mechanism is used to identify the pixels corresponding to the difference between the lowest point of the liquid level and the scale height and convert them into the height h. The output mechanism is used to output the liquid level height, and the liquid level height H1=H+h. The judgment mechanism is used to determine whether to measure the liquid level heights on both sides. If so, the pressure value is directly output, P=ρ*g*ΔH, where h is the height of the liquid column on one side of the U-tube, ρ is the density of the measured liquid, g is the gravitational acceleration constant, ΔH=H1-H2, and if not, the height, movement speed and direction are readjusted through the adjustment mechanism.

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