A pipe fluid monitoring sensor

Abstract

This application relates to the field of photoelectric sensors, and more particularly to a fluid monitoring sensor for pipes, comprising a housing, a pipe optical structure, and an electronic circuit structure. The pipe optical structure is fixed to the housing by a limiting structure and includes a light-emitting lens, a first light-receiving lens, a second light-receiving lens, a pipe connection structure, and the limiting structure. The electronic circuit structure is rigidly connected to the housing by an internal fixing bracket and includes a PCB circuit board, and a light-emitting LED, a first light-receiving PD, and a second light-receiving PD soldered to the PCB circuit board. The optical axis of the light-emitting LED is coaxially aligned with the optical center of the light-emitting lens, the optical axis of the first light-receiving PD is coaxially aligned with the optical center of the first light-receiving lens, and the optical axis of the second light-receiving PD is coaxially aligned with the optical center of the second light-receiving lens. This application has the advantage that the detection process and results are unaffected by the fluid state when detecting fluids in various thin tubular structures.

Description

Technical Field

[0001] This application relates to the field of photoelectric sensors, and more particularly to a sensor for monitoring fluid in a pipe. Background Technology

[0002] In fluid transport systems across medical, chemical, industrial equipment, and power tool industries, accurately determining the presence of fluid within pipelines and monitoring its flow status in real time is crucial for ensuring safe equipment operation and process reliability. In medical settings, ensuring unobstructed intravenous lines is essential to prevent life support equipment from being disrupted due to fluid interruptions; in the chemical industry, preventing pipeline leaks or media drying out can lead to safety accidents; industrial equipment relies on lubrication systems to provide a stable fluid supply and reduce mechanical wear; and fluid loop monitoring in power tools is critical to the lifespan of power components. Addressing these needs, in-pipe fluid monitoring sensors, through a non-invasive design, provide real-time feedback on fluid presence, flow rate, and pressure changes, offering data support for multiple industries, reducing the risk of equipment burn-out and leaks, and enabling intelligent management of fluid transport systems.

[0003] Existing technologies for monitoring fluid states within pipes have significant shortcomings. Traditional sensors often employ a single through-beam optical principle, determining fluid presence by the obstruction of light signals between the transmitter and receiver. This approach is susceptible to ambient light interference, has limited ability to identify transparent liquids, bubbles, or impurities, and is prone to misjudgment under complex flow conditions. Some single-reflection sensors utilize silicone coupling to the pipe body; due to differences in material refractive indices, this results in low optical coupling efficiency, high signal loss, and a small detection range, limiting their application to specific pipe diameters or highly transparent fluids. Sensors relying solely on optical reflection are also problematic, as they are highly sensitive to fluid type, only capable of monitoring fluids with good flowability, high permeability, and internal purity, and cannot meet the detection needs of liquids containing particles, high viscosity, or dark colors.

[0004] Currently, no technical solution can effectively combine the principles of multiple optical reflection and optical transmission to solve the problems of low detection reliability, poor coupling efficiency, and insufficient fluid adaptability. This invention, through innovative design, combines multiple optical reflection and optical transmission, employing an integrated design of the optical structure and tube body to improve optical efficiency and expand the detection range. By reducing false positives through multi-principle fusion processing, it can accurately detect the presence or absence of fluid in various thin tubular structures without relying on fluid color, bubbles, impurities, or other conditions. It is applicable to a wide range of scenarios, including medical, automation, chemical, and smart factory applications. Utility Model Content

[0005] In order to ensure that the detection process and results are unaffected by the fluid state when detecting fluids in various thin tubular structures, this application provides an in-tube fluid monitoring sensor.

[0006] This application provides a pipe fluid monitoring sensor, which adopts the following technical solution:

[0007] A pipe fluid monitoring sensor, comprising:

[0008] shell;

[0009] The tube optical structure is fixed to the outer shell by a limiting structure. The tube optical structure includes a light-emitting lens, a first light-receiving lens, a second light-receiving lens, a tube connection structure, and a limiting structure.

[0010] An electronic circuit structure, wherein the electronic circuit structure is rigidly connected by an internal fixing bracket of the housing, the electronic circuit structure includes a PCB circuit board, and light-emitting LEDs, a first light-receiving PD and a second light-receiving PD soldered to the PCB circuit board;

[0011] Wherein, the optical axis of the light-emitting LED is coaxially aligned with the optical center of the light-emitting lens, the optical axis of the first light-receiving PD is coaxially aligned with the optical center of the first light-receiving lens, and the optical axis of the second light-receiving PD is coaxially aligned with the optical center of the second light-receiving lens.

[0012] By adopting the above technical solution, the light-emitting LED and the light-emitting lens, the first light-receiving PD and the first light-receiving lens, and the second light-receiving PD and the second light-receiving lens are respectively aligned with the optical axis and the optical center, which can minimize the optical signal transmission loss, improve the light convergence efficiency and detection sensitivity. Through the design of dual light-receiving lenses and dual light-receiving PDs, a multi-angle optical detection path can be constructed to realize three-dimensional monitoring of the fluid state inside the pipe. Compared with a single detection path, it can more accurately identify the fluid state, bubble distribution and impurity conditions, and significantly reduce the detection error rate.

[0013] Preferably, the upper surface of the tube optical structure is provided with an anti-reflection structure layer, which is formed by blackening treatment, frosting treatment or a wedge array process at a specific angle.

[0014] By adopting the above technical solutions, the anti-reflection structure layer can effectively suppress interference caused by external ambient light and internal light reflection. After blackening treatment, the reflective structure layer can absorb excess stray light, reduce the reflection loss of the reflective structure layer, and prevent it from entering the light-receiving lens and light-receiving PD. The frosted treatment or specific angle wedge array process reduces the intensity of reflected light by changing the light reflection path, and increases the number of effective detection lights emitted by the light-emitting LED, so that more light can pass through the structure layer to participate in fluid detection.

[0015] Preferably, the optical surfaces of the light-emitting lens, the first light-receiving lens, and the second light-receiving lens are all aspherical, and the aspherical coefficient of the light-emitting lens is different from that of the first light-receiving lens and the second light-receiving lens.

[0016] By adopting the above technical solution and using a special curved surface shape, light is more accurately focused or collimated after refraction on the lens surface, avoiding light divergence or convergence deviation, improving light utilization, reducing light energy loss, and ensuring that the light emitted by the LED is efficiently projected into the detection area. At the same time, the first and second light-receiving lenses can more accurately capture the light reflected or transmitted by the fluid. The light-emitting lens and the light-receiving lens use different aspherical coefficients, which can optimize the reception efficiency of reflected and transmitted light respectively, ensuring that the light information reflecting the true state of the fluid can be accurately captured under different fluid states (such as complex working conditions containing bubbles, impurities, etc.), thereby achieving high-precision detection of the fluid state inside the pipe and reducing detection errors and the risk of misjudgment.

[0017] Preferably, the light-emitting lens, the first light-receiving lens, the second light-receiving lens, the limiting structure, and the pipeline connection structure constitute an integrated structure;

[0018] The light-emitting lens, the first light-receiving lens, the second light-receiving lens, the limiting structure, and the pipeline connection structure are all made of optical materials with a light transmittance greater than 90%, such as optical plastics or optical glass.

[0019] The optical plastic is selected from at least one of PC, PMMA, or PS.

[0020] By adopting the above technical solution, the light-emitting lens, the first light-receiving lens, the second light-receiving lens, the limiting structure, and the pipeline connection structure form an integrated structure. This reduces the connection gaps and assembly errors between components in the traditional split structure, enhances the overall structural rigidity, and under complex working conditions, the integrated structure can effectively resist the influence of external forces, avoid optical alignment deviations caused by component loosening or displacement, and ensure stable detection accuracy. The use of optical materials with a transmittance greater than 90% to manufacture each optical component can minimize the absorption and scattering loss of light during transmission, ensure that the light emitted by the light-emitting LED is efficiently projected to the detection area through the lens group, and enable the light-receiving lens to accurately receive the light signal after the fluid action. This enhances the ability to capture weak optical changes in the fluid (such as differences in light refraction and reflection caused by bubbles and impurities), thereby achieving high-sensitivity detection of the fluid state inside the pipe and reducing detection blind spots and the risk of misjudgment.

[0021] Preferably, the first light-receiving PD and the second light-receiving PD are arranged in a staggered manner along the axial direction of the fluid pipe, wherein the second light-receiving PD is further away from the light-emitting LED than the first light-receiving PD.

[0022] By adopting the above technical solution, the first light-receiving PD can preferentially receive light reflected or transmitted through the fluid over a short distance, quickly capturing near-field optical changes in the fluid. The second light-receiving PD, being farther away from the light-emitting LED, can acquire light signals that have traveled a longer optical path and are more fully affected by the fluid. It can simultaneously monitor the optical characteristics of the fluid at different positions and depths, performing three-dimensional detection of the fluid state inside the pipe. This avoids information omissions caused by a single detection point, significantly improving the comprehensiveness and completeness of fluid monitoring. When interference factors such as bubbles and impurities appear in the pipeline, the light intensity, phase, and other parameters received by the first and second light-receiving PDs will differ. Through algorithmic processing of these difference signals, interference factors can be effectively identified, accurately distinguishing between real fluid state changes and interference signals, thus improving the accuracy and reliability of the detection results.

[0023] Preferably, the inner wall of the optical structure portion of the tube is a smooth reflective surface;

[0024] The center distance between the light-emitting lens and the first light-receiving lens is L1, and the center distance between the light-emitting lens and the second light-receiving lens is L2, where L2 > L1, and the difference between L2 and L1 is in the range of 5-15mm.

[0025] By adopting the above technical solution, the first light-receiving lens mainly receives light reflected or transmitted through the fluid over a short distance, reflecting the near-surface state of the fluid; the second light-receiving lens receives light that has undergone more reflections and penetrated deeper fluid layers, providing information about the fluid's interior. When the difference between L2 and L1 is less than 5mm, the difference between the two optical paths is too small to provide complementary information; when the difference between L2 and L1 is greater than 15mm, the intensity of the light received by the second light-receiving lens is significantly reduced, affecting the reliability of the detection.

[0026] Preferably, the electronic circuit structure further includes a signal processing module, the input terminal of which is electrically connected to the signal output terminals of the first light-receiving PD and the second light-receiving PD, respectively.

[0027] By adopting the above technical solution, during the monitoring of fluid inside the pipe, factors such as ambient light and random reflections of impurities inside the fluid can easily generate interference signals. The signal processing module can simultaneously receive the output signals of the first light-receiving PD and the second light-receiving PD, and perform real-time comparative analysis and algorithm processing on the two signals. When one signal fluctuates abnormally due to interference, the signal processing module can correct it based on the other stable signal, avoiding misjudgment caused by interference of a single light-receiving PD, and ensuring that the sensor continuously outputs stable and reliable detection data under complex working conditions. The first light-receiving PD and the second light-receiving PD are arranged in an axially staggered manner to achieve high-precision fluid state judgment and improve detection accuracy.

[0028] Preferably, the pipeline connection structure is provided with a fluid sealing interface, which is used to connect to an external testing pipeline.

[0029] By adopting the above technical solution, the fluid sealing interface, through its precisely designed sealing structure, can form a reliable sealing connection after the external detection pipeline and sensor are connected, effectively preventing fluid leakage and improving the safety and reliability of the equipment.

[0030] Preferably, the outer shell includes a light-shielding cavity, the inner wall of which is provided with an optical absorption coating, and the outer shell is provided with an anti-reverse mounting groove that cooperates with the limiting structure; the outer shell includes a front shell and a rear shell, and the outer shell (9) is further provided with a waterproof sealant layer filling the joints, or

[0031] The rear housing is formed by applying a waterproof sealant layer to the entire back of the PCB.

[0032] By adopting the above technical solutions, the light-shielding cavity, in conjunction with the optical absorption coating on the inner wall, effectively shields the sensor from ambient light, preventing stray light from interfering with the optical detection signal. This ensures that the first and second light-receiving PDs only receive the effective optical signal after the fluid has acted upon them. The anti-reverse mounting slots on the outer shell precisely match the limiting structure of the tube's optical structure, forming a unique and correct installation guide. This avoids component reversal or misalignment caused by human assembly negligence, ensuring that the optical axes of the light-emitting lens, the light-receiving lens, and the electronic circuit structure always remain coaxially aligned. If the seams of the outer shell are filled with a waterproof sealant layer, this layer can form a tight waterproof barrier, effectively preventing liquids, moisture, and dust from entering the sensor, adapting to harsh working environments such as humid, dusty, and outdoor conditions. If the rear shell is entirely filled with a waterproof sealant layer on the back of the PCB, one rear shell can be saved, making the overall weight of the device lighter and saving costs while achieving waterproof, oil-proof, and structurally robust effects.

[0033] Preferably, the limiting structure includes asymmetrically arranged positioning protrusions, and the positioning protrusions and the corresponding anti-reverse mounting slots on the outer shell form an anti-reverse mounting structure.

[0034] By adopting the above technical solution, the anti-reverse assembly structure reduces the dependence of the assembly process on the skill level of the operators through intuitive physical guidance. Workers do not need to repeatedly check the installation direction of the parts, and can quickly and accurately complete the sensor assembly, reducing rework and debugging caused by installation errors, effectively reducing the labor and time costs in the production process. At the same time, the tight fit between the positioning protrusion and the slot effectively resists the action of external forces such as vibration and impact, preventing the parts from shifting or loosening during use.

[0035] In summary, this application includes at least one of the following beneficial technical effects:

[0036] 1. The light-emitting LED and the light-emitting lens, the first light-receiving PD and the first light-receiving lens, and the second light-receiving PD and the second light-receiving lens are all coaxially aligned with the optical axis and the optical center, which can minimize the optical signal transmission loss, improve the light convergence efficiency and detection sensitivity. Through the design of dual light-receiving lenses and dual light-receiving PDs, a multi-angle optical detection path can be constructed to realize three-dimensional monitoring of the fluid state inside the pipe. Compared with a single detection path, it can more accurately identify the fluid state, bubble distribution and impurity status, and significantly reduce the detection error rate.

[0037] 2. Through a special curved surface shape, light is more accurately focused or collimated after refraction on the lens surface, avoiding light divergence or convergence deviation, improving light utilization, reducing light energy loss, and ensuring that the light emitted by the LED is efficiently projected onto the detection area. At the same time, the first and second light-receiving lenses can more accurately capture the light reflected or transmitted by the fluid. The light-emitting lens and the light-receiving lens use different aspherical coefficients, which can optimize the reception efficiency of reflected and transmitted light respectively, ensuring that the light information reflecting the true state of the fluid can be accurately captured under different fluid conditions (such as complex working conditions containing bubbles, impurities, etc.), thereby achieving high-precision detection of the fluid state inside the pipe and reducing detection errors and the risk of misjudgment. Attached Figure Description

[0038] Figure 1 This is an overall view of the tube's optical structure in an embodiment of this application;

[0039] Figure 2 This is a schematic diagram showing the front structure of the outer casing.

[0040] Explanation of reference numerals in the attached drawings: 1. Light-emitting LED; 2. Light-emitting lens; 3. First light-receiving lens; 4. First light-receiving PD; 5. Second light-receiving lens; 6. Second light-receiving PD; 7. Limiting structure; 8. Pipeline connection structure; 9. Housing. Detailed Implementation

[0041] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0042] This application discloses an in-pipe fluid monitoring sensor. (Refer to...) Figure 1 and Figure 2The in-pipe fluid monitoring sensor includes a housing 9, a pipe optical structure, and an electronic circuit structure. The pipe optical structure is fixed to the housing 9 by a limiting structure 7. The pipe optical structure includes a light-emitting lens 2, a first light-receiving lens 3, a second light-receiving lens 5, a pipe connection structure 8, and the limiting structure 7. The light-emitting lens 2, the first light-receiving lens 3, the second light-receiving lens 5, the limiting structure 7, and the pipe connection structure 8 form an integrated structure. In an optional embodiment, the light-emitting lens 2, the first light-receiving lens 3, the second light-receiving lens 5, the limiting structure 7, and the pipe connection structure 8 are all made of an optical material with a light transmittance greater than 90%, which is an optical plastic or optical glass. In a preferred embodiment, the optical plastic is selected from at least one of PC, PMMA, or PS.

[0043] The light-emitting lens 2, the first light-receiving lens 3, the second light-receiving lens 5, the limiting structure 7, and the pipeline connection structure 8 form an integrated structure, reducing the connection gaps and assembly errors between components in the traditional split structure, enhancing the overall structural rigidity. Under complex working conditions, the integrated structure can effectively resist the influence of external forces, avoid optical alignment deviations caused by component loosening or displacement, and ensure stable detection accuracy. The optical components are manufactured using optical materials with a transmittance greater than 90%, which can minimize the absorption and scattering loss of light during transmission, ensuring that the light emitted by the light-emitting LED 1 is efficiently projected to the detection area through the lens group, and enabling the light-receiving lens to accurately receive the light signal after the fluid action. This enhances the ability to capture weak optical changes in the fluid, such as differences in light refraction and reflection caused by bubbles and impurities, thereby achieving high-sensitivity detection of the fluid state inside the pipe and reducing the detection blind zone and the risk of misjudgment.

[0044] The upper surface of the tube optical structure is provided with an anti-reflection layer, which is formed through blackening, frosting, or a wedge array process at a specific angle. The anti-reflection layer effectively suppresses interference caused by ambient light and internal light reflection. After blackening, the reflective layer absorbs excess stray light, reducing reflection loss and preventing it from entering the light-receiving lens and PD. Frosting or a wedge array process at a specific angle changes the light reflection path, reducing the intensity of reflected light and increasing the number of effective detection rays emitted by the LED1, allowing more light to pass through the structure layer and participate in fluid detection. The inner cavity of the tube optical structure 8 can be a pipe with various geometric cross-sections. In an optional embodiment, the inner cavity of the tube optical structure 8 is a circular cross-section pipe, and the inner wall of the tube optical structure 8 is a smooth reflective surface. The pipe connection structure 8 is provided with a fluid-sealed interface for connecting to an external detection pipe.

[0045] In an optional embodiment, the optical surfaces of the light-emitting lens 2, the first light-receiving lens 3, and the second light-receiving lens 5 are all aspherical, and the aspherical coefficient of the light-emitting lens 2 is different from that of the first light-receiving lens 3 and the second light-receiving lens 5. Through the special curved surface shape, light is more accurately focused or collimated after refraction on the lens surface, avoiding light divergence or convergence deviations, improving light utilization, and reducing light energy loss. Simultaneously, the first light-receiving lens 3 and the second light-receiving lens 5 can more accurately capture light reflected or transmitted by the fluid. The different aspherical coefficients of the light-emitting lens 2 and the light-receiving lens can optimize the reception efficiency of reflected and transmitted light respectively, ensuring accurate capture of light information reflecting the true state of the fluid under different fluid conditions, such as complex conditions containing bubbles and impurities.

[0046] The electronic circuit structure is rigidly connected via an internal fixing bracket in the housing 9. The electronic circuit structure includes a PCB circuit board, and LED1, a first light-receiving PD4, and a second light-receiving PD6 soldered to the PCB circuit board. The optical axis of LED1 is coaxially aligned with the optical center of the light-emitting lens 2; the optical axis of the first light-receiving PD4 is coaxially aligned with the optical center of the first light-receiving lens 3; and the optical axis of the second light-receiving PD6 is coaxially aligned with the optical center of the second light-receiving lens 5. Optionally, the first light-receiving PD4 and the second light-receiving PD6 are arranged with a staggered arrangement along the axial direction of the fluid pipe, wherein the second light-receiving PD6 is further away from LED1 than the first light-receiving PD4.

[0047] The first light-receiving PD4 can preferentially receive light reflected or transmitted through the fluid over a short distance, quickly capturing near-field optical changes in the fluid. The second light-receiving PD6, being further away from the light-emitting LED1, can acquire light signals that have traveled a longer optical path and are more fully affected by the fluid. It can simultaneously monitor the optical characteristics of the fluid at different positions and depths, performing three-dimensional detection of the fluid state inside the pipe. This avoids information omissions caused by a single detection point, significantly improving the comprehensiveness and completeness of fluid monitoring. When interference factors such as bubbles and impurities appear in the pipeline, the light intensity, phase, and other parameters received by the first and second light-receiving PDs will differ. Through algorithmic processing of these difference signals, interference factors can be effectively identified, accurately distinguishing between real fluid state changes and interference signals, thus improving the accuracy and reliability of the detection results.

[0048] In an optional embodiment, the center-to-center distance between the emitting lens 2 and the first receiving lens 3 is L1, and the center-to-center distance between the emitting lens 2 and the second receiving lens 5 is L2, where L2 > L1, and the difference between L2 and L1 ranges from 5 to 15 mm. L1 is sensitive to the fluid-filled state; L2 is sensitive to the empty pipe and turbid state. The smooth inner wall of the circular cross-section pipe forms a highly efficient reflective surface, allowing the light emitted by the emitting lens 2 to maintain high intensity even after multiple reflections within the pipe. The first receiving lens 3 mainly receives light reflected once or a few times from the fluid surface, reflecting the near-surface state of the fluid; the second receiving lens 5 receives light that has undergone more reflections and penetrated deeper fluid layers, providing information about the fluid's internal structure.

[0049] In an optional embodiment, when the difference between L2 and L1 is less than 5 mm, the difference between the two optical paths is too small to provide complementary information; when the difference between L2 and L1 is greater than 15 mm, the light intensity received by the second light-receiving lens 5 is significantly reduced, affecting the reliability of detection. In use, the light-emitting LED 1 emits infrared light, which is collimated by the light-emitting lens 2 and penetrates the fluid to be measured. In the full tube state, the fluid light-guiding effect makes the signal intensity of the first light-receiving PD4 greater than that of the second light-receiving PD6; in the empty tube state, the air transmittance makes the signal intensity of the second light-receiving PD6 greater than that of the first light-receiving PD4; in the turbid fluid state, the signal intensity difference between the first light-receiving PD4 and the second light-receiving PD6 is reduced to within the threshold range; in the bubble / residue state, the amplitude jump phenomenon occurs between the two signals.

[0050] Optionally, the electronic circuit structure also includes a signal processing module, whose input terminals are electrically connected to the signal output terminals of the first light-receiving PD4 and the second light-receiving PD6, respectively. During the monitoring of fluid inside the pipe, factors such as ambient light and random reflections from impurities inside the fluid can easily generate interference signals. By simultaneously receiving the output signals of the first light-receiving PD4 and the second light-receiving PD6, the signal processing module can perform real-time comparative analysis of the two signals. When one signal experiences abnormal fluctuations due to interference, the signal processing module can correct it based on the other stable signal, avoiding misjudgments caused by interference with a single light-receiving PD. This ensures that the sensor continuously outputs stable and reliable detection data under complex operating conditions. The axially staggered arrangement of the first light-receiving PD4 and the second light-receiving PD6 enables high-precision fluid state judgment and improves detection accuracy.

[0051] The outer casing 9 includes a light-shielding cavity with an optical absorption coating on its inner wall. The outer casing 9 also has an anti-reverse mounting groove that mates with the limiting structure 7. The limiting structure 7 includes asymmetrically arranged positioning protrusions, which, together with the corresponding anti-reverse mounting grooves on the outer casing 9, form an anti-reverse mounting structure. The light-shielding cavity, in conjunction with the optical absorption coating on its inner wall, effectively shields the sensor from ambient light, preventing stray light from interfering with the optical detection signal. This ensures that the first light-receiving PD4 and the second light-receiving PD6 only receive the effective optical signal after fluid action. The anti-reverse mounting groove on the outer casing 9 precisely mates with the limiting structure 7 of the tube's optical structure, forming a unique and correct installation guide. This prevents component reversal or misalignment due to human assembly negligence, ensuring that the optical axes of the emitting lens 2, the receiving lens, and the electronic circuit structure remain coaxially aligned. Simultaneously, the tight fit between the positioning protrusions and the groove effectively resists external forces such as vibration and impact, preventing component displacement or loosening during use.

[0052] The housing 9 includes a front housing and a rear housing. In an optional embodiment, the housing 9 is further provided with a waterproof sealant layer for filling gaps. The waterproof sealant layer can form a tight waterproof barrier, effectively preventing liquids, moisture and dust from entering the sensor and adapting to harsh working environments such as humid, dusty and outdoor environments. In an optional embodiment, the rear housing is a waterproof sealant layer applied to the entire back of the PCB. If the rear housing is an entire waterproof sealant layer applied to the back of the PCB, one rear housing can be saved, making the overall weight of the device lighter and saving costs while achieving waterproof, oil-proof and structurally robust effects.

[0053] The implementation principle of this application embodiment is as follows: the light-emitting LED1 and the light-emitting lens 2, the first light-receiving PD4 and the first light-receiving lens 3, and the second light-receiving PD6 and the second light-receiving lens 5 are respectively aligned coaxially with the optical center, which can minimize optical signal transmission loss, improve light convergence efficiency and detection sensitivity. Through the design of dual light-receiving lenses and dual light-receiving PDs, a multi-angle optical detection path can be constructed to realize three-dimensional monitoring of the fluid state inside the pipe. Compared with a single detection path, it can more accurately identify the fluid state, bubble distribution and impurities, and significantly reduce the detection error rate. In use, the light-emitting LED1 emits infrared light, which penetrates the fluid to be tested after being collimated by the light-emitting lens 2. When the pipe is full, the fluid guiding effect makes the signal intensity of the first light-receiving PD4 greater than that of the second light-receiving PD6; when the pipe is empty, the air transmittance makes the signal intensity of the second light-receiving PD6 greater than that of the first light-receiving PD4; when the fluid is turbid, the signal intensity difference between the first light-receiving PD4 and the second light-receiving PD6 is reduced to within the threshold range; when there are bubbles / residues, the amplitude jump phenomenon occurs between the two signals.

[0054] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A pipe-in-fluid monitoring sensor, characterized by, include: Outer shell (9); The tube optical structure is fixed to the outer shell (9) by a limiting structure (7). The tube optical structure includes a light-emitting lens (2), a first light-receiving lens (3), a second light-receiving lens (5), a pipeline connection structure (8), and a limiting structure (7). The electronic circuit structure is rigidly connected to the internal fixing bracket of the outer shell (9). The electronic circuit structure includes a PCB circuit board, and light-emitting LED (1), first light-receiving PD (4) and second light-receiving PD (6) soldered to the PCB circuit board. The optical axis of the light-emitting LED (1) is coaxially aligned with the optical center of the light-emitting lens (2), the optical axis of the first light-receiving PD (4) is coaxially aligned with the optical center of the first light-receiving lens (3), and the optical axis of the second light-receiving PD (6) is coaxially aligned with the optical center of the second light-receiving lens (5).

2. The in-pipe fluid monitoring sensor according to claim 1, characterized in that, The upper surface of the tube's optical structure is provided with an anti-reflection layer, which is formed by blackening, frosting, or a wedge array process at a specific angle.

3. The in-pipe fluid monitoring sensor according to claim 1, characterized in that, The optical surfaces of the light-emitting lens (2), the first light-receiving lens (3), and the second light-receiving lens (5) are all aspherical, and the aspherical coefficient of the light-emitting lens (2) is different from that of the first light-receiving lens (3) and the second light-receiving lens (5).

4. The in-pipe fluid monitoring sensor according to claim 3, characterized in that, The light-emitting lens (2), the first light-receiving lens (3), the second light-receiving lens (5), the limiting structure (7), and the pipeline connection structure (8) constitute an integrated structure; The light-emitting lens (2), the first light-receiving lens (3), the second light-receiving lens (5), the limiting structure (7), and the pipeline connection structure (8) are all made of optical materials with a light transmittance greater than 90%, which are optical plastics or optical glass; The optical plastic is selected from at least one of PC, PMMA, or PS.

5. The in-pipe fluid monitoring sensor according to claim 1, characterized in that, The first light-receiving PD (4) and the second light-receiving PD (6) are arranged in a staggered manner along the axial direction of the fluid pipe, wherein the second light-receiving PD (6) is further away from the light-emitting LED (1) than the first light-receiving PD (4).

6. The in-pipe fluid monitoring sensor according to claim 5, characterized in that, The inner wall of the optical structure of the tube is a smooth reflective surface; The center distance between the light-emitting lens (2) and the first light-receiving lens (3) is L1, and the center distance between the light-emitting lens (2) and the second light-receiving lens (5) is L2, where L2>L1 and the difference between L2 and L1 is 5-15mm.

7. The in-pipe fluid monitoring sensor according to claim 1, characterized in that, The electronic circuit structure also includes a signal processing module, the input of which is electrically connected to the signal output of the first light-receiving PD (4) and the second light-receiving PD (6).

8. The in-pipe fluid monitoring sensor according to claim 1, characterized in that, The pipeline connection structure (8) is provided with a fluid sealing interface, which is used to connect to an external detection pipeline.

9. The in-pipe fluid monitoring sensor according to claim 1, characterized in that, The outer shell (9) includes a light-shielding cavity, the inner wall of which is provided with an optical absorption coating. The outer shell (9) is provided with an anti-reverse mounting groove that cooperates with the limiting structure (7). The outer shell (9) includes a front shell and a rear shell. The outer shell (9) is also provided with a waterproof sealant layer filling the joints. The rear housing is formed by applying a waterproof sealant layer to the entire back of the PCB.

10. The in-pipe fluid monitoring sensor according to claim 9, characterized in that, The limiting structure (7) includes asymmetrically arranged positioning protrusions, which together with the anti-reverse mounting slots on the outer shell (9) form an anti-reverse mounting structure.

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