Optoelectronic liquid level sensor

Abstract

The application relates to the technical field of sensors, and specifically discloses an optoelectronic liquid level sensor, which comprises a shell, a detection module screw-connected in the shell, and a transparent lens arranged at an axial end of the shell and covered with a waterproof film along the outer wall of the transparent lens; wherein the transparent lens is in a conical structure. The application is improved by designing the prism lens into a conical structure, using the curved surface characteristics of the conical lens to form a continuous gradient of the incident angle distribution when light is incident to the surface of the lens; when a local area is interfered by water droplets and fog, a large number of light rays satisfying the total reflection condition still exist in the uncovered area, so that the sudden change of the overall light intensity is avoided to prevent misjudgment; the waterproof film reduces the adhesion of water droplets and fog on the surface of the lens (droplets are easy to roll off instead of spreading) through the low surface energy characteristics, thereby reducing the possibility of direct contact of the micro-liquid with the surface of the lens to damage the light path, and the anti-interference ability is synergistically enhanced with the conical structure to avoid misjudgment and detection distortion.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and in particular to a photoelectric liquid level sensor. Background Technology

[0002] A photoelectric liquid level sensor is a sensor that uses the optical properties of light, such as reflection and refraction, to detect liquid levels (e.g., liquid height, presence or absence of liquid). Its core working principle is as follows: when the sensing end is not in contact with the liquid, the light emitted by the light-emitting element is reflected (or propagates along its original path) in the air, and the photosensitive element receives a strong light signal. However, when the sensing end comes into contact with the liquid, the light is refracted (or its reflection characteristics change) at the liquid-air interface, and the intensity of the light signal received by the photosensitive element changes significantly (weakening or disappearing). The sensor identifies this change in light signal and converts the liquid level status into an electrical signal (such as a switch signal or analog signal), thereby achieving liquid level monitoring or control.

[0003] Traditional photoelectric liquid level sensors often have angular lenses. Because of their single angle of incidence, the angular parts are extremely sensitive to changes in the medium, such as water droplets or mist. If the total internal reflection condition is disrupted locally, the sensor will misjudge the presence of water, resulting in detection distortion. Utility Model Content

[0004] This application provides a photoelectric liquid level sensor, which aims to solve the problem of detection distortion in traditional photoelectric liquid level sensors.

[0005] In one embodiment, a photoelectric liquid level sensor is provided, comprising:

[0006] case;

[0007] A detection module is threadedly connected to the housing.

[0008] A transparent lens is provided at one axial end of the housing, and the transparent lens is covered with a waterproof membrane along its outer wall;

[0009] The transparent lens has a conical structure, which allows the light emitted by the detection module to form a continuous gradient of incident angle distribution when it is incident on its surface, through the curved surface characteristics.

[0010] In one embodiment, the detection module includes:

[0011] The optical carrier includes a transmitter and a receiver mounted on an optical carrier plate. A sleeve is connected to the end of the optical carrier plate away from the transmitter. The optical carrier plate has several air outlets arranged in a ring in the middle to allow the optical carrier plate and the sleeve to communicate with each other.

[0012] In one embodiment, a motor is provided along the inner axial direction of the sleeve, and a fan is driven to the output end of the motor. The motor is connected to the inner wall of the sleeve through a connecting rod, and the axes of the sleeve, the motor, and the fan coincide.

[0013] In one embodiment, the motor has a cross-shaped plate at the end away from the fan, and several heating wires are wound at equal intervals along the length of the cross-shaped plate. The end of the cross-shaped plate away from the motor has a gap with the optical carrier plate.

[0014] In one embodiment, a humidity sensor and a temperature sensor are mounted on the side of the optical carrier away from the sleeve, and the humidity sensor and temperature sensor are positioned away from the air outlet.

[0015] In one embodiment, the end cover plate of the sleeve away from the optical carrier plate has a plurality of air inlet and outlet holes arranged in a ring. A wire harness is provided at the center of the cover plate and is arranged to avoid the air inlet and outlet holes. A connector is provided at the end of the wire harness away from the sleeve. The transmitter, receiver, humidity sensor and temperature sensor are electrically connected to the connector through the wire harness.

[0016] In one embodiment, the outer periphery of the optical carrier plate and the cover plate is provided with a connecting ring, and the outer periphery of the connecting ring is provided with an external thread that matches the internal thread of the housing, so that the detection module is threadedly connected to the housing.

[0017] The beneficial effects of this application are as follows: By designing the prism lens as a conical structure, improvements are achieved. Utilizing the curved surface characteristics of the conical lens, light incident on its surface forms a continuous gradient of incident angles. When a local area is interfered with by water droplets or fog, the uncovered area still contains a large amount of light satisfying the total internal reflection condition, avoiding misjudgments caused by sudden changes in overall light intensity. Simultaneously, the geometric shape of the conical surface reduces the probability of droplet adhesion and retention (droplets are more easily detached due to gravity or vibration), and allows droplets to naturally spread into a gradient water film, mitigating the refraction interference of sudden changes in the medium on the light path. Ultimately, this improves the accuracy and anti-interference capability of the sensor in liquid level detection under complex environments. The waterproof membrane, through its low surface energy characteristics, reduces the adhesion of water droplets and fog to the lens surface (droplets tend to roll off rather than spread), thereby reducing the possibility of trace amounts of liquid directly contacting the lens surface and damaging the light path. This, combined with the conical structure, enhances anti-interference capability, thus avoiding misjudgments and detection distortion. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the shell structure shown in the embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the detection module shown in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the structure of the optical carrier plate shown in the embodiments of this application;

[0022] Figure 4 This is a schematic diagram of the internal structure of the sleeve shown in an embodiment of this application;

[0023] Figure 5 This is another perspective view of the inside of the sleeve shown in the embodiments of this application;

[0024] Figure 6 This is a schematic diagram of the structure of the wire harness shown in the embodiment of this application.

[0025] Labels for each item in the figure:

[0026] 1. Housing; 2. Detection module; 3. Transparent lens; 4. Transmitter head; 5. Receiver head; 6. Optical carrier plate; 7. Sleeve; 8. Air outlet; 9. Motor; 10. Fan; 11. Connecting rod; 12. Cross plate; 13. Heating wire; 14. Humidity sensor; 15. Temperature sensor; 16. Air inlet and outlet; 17. Cover plate; 18. Wiring harness; 19. Connector head; 20. Connecting ring; 21. External thread. Detailed Implementation

[0027] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application. Similarly, the following examples are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0032] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] This application makes improvements and innovations, and proposes the following embodiments.

[0034] Example 1:

[0035] See Figures 1 to 3 In one embodiment, a photoelectric liquid level sensor is provided, comprising:

[0036] Casing 1;

[0037] The detection module 2 is threadedly connected to the housing 1;

[0038] A transparent lens 3 is disposed at one axial end of the housing 1, and the transparent lens 3 is covered with a waterproof membrane along its outer wall.

[0039] The transparent lens 3 has a conical structure, which allows the light emitted by the detection module 2 to form a continuous gradient of incident angle distribution when it is incident on its surface through the curved surface characteristics.

[0040] Specifically, housing 1 includes a nut section and a threaded section. The end of the threaded section is connected to a transparent lens 3. The detection module 2 is threaded into housing 1. The entire device is installed at the location to be tested via the nut section and the threaded section for liquid level detection. Detection module 2 emits detection light and receives light reflected / refracted by the transparent lens 3. It determines the liquid level status by observing changes in the light signal and by observing changes in the intensity of the electrical signal. For example, it receives a strong signal during total internal reflection and a weak signal when the liquid covers the area. It outputs a detection result reflecting the liquid level status, such as a switch signal indicating "water present" or "water absent".

[0041] This technical solution addresses the problem in traditional photoelectric liquid level sensors where the prism edges are prone to total internal reflection when exposed to trace amounts of media such as water droplets or mist, leading to detection distortion. The solution improves upon this by redesigning the prism lens as a conical structure. The curved surface of the conical lens creates a continuous gradient of incident angles as light strikes its surface. Even when a localized area is affected by water droplets or mist, the uncovered area still contains a significant amount of light satisfying the total internal reflection condition, preventing misjudgments caused by sudden changes in overall light intensity. Simultaneously, the conical surface reduces the probability of droplet adhesion and retention (droplets are more easily detached due to gravity or vibration), and allows the droplets to naturally spread into a gradient water film, mitigating the refraction interference of sudden changes in the medium on the light path. Ultimately, this improves the accuracy and anti-interference capability of the sensor in liquid level detection under complex environments. The waterproof membrane reduces the adhesion of water droplets and fog to the lens surface through its low surface energy properties (droplets tend to roll off rather than spread), thereby reducing the possibility of small amounts of liquid directly contacting the lens surface and damaging the optical path. In conjunction with the conical structure, it enhances anti-interference capabilities, thus avoiding misjudgment and detection distortion.

[0042] In this embodiment, the light transmittance of the transparent lens 3 and the light path guidance design of the conical surface ensure that the reflection / refraction law of light is not affected by structural changes during normal liquid level detection, thus retaining the liquid level detection function and solving the problem of sensitive misjudgment caused by traditional sharp edges.

[0043] Example 2:

[0044] See Figure 3Based on Embodiment 1, in one solution, the detection module 2 includes:

[0045] The optical carrier plate 6 has a transmitter 4 and a receiver 5 mounted on it. The end of the optical carrier plate 6 away from the transmitter 4 is connected to a sleeve 7. The optical carrier plate 6 has a plurality of air outlet holes 8 arranged in a ring in the middle so that the optical carrier plate 6 and the sleeve 7 are in communication.

[0046] Specifically, the transmitter 4 and receiver 5 are detachably connected to the optical carrier plate 6. The optical carrier plate 6 supports the transmitter 4, receiver 5, and other components. The transmitter 4 and receiver 5 are installed outside the air outlet 8, avoiding it. The transmitter 4 and receiver 5 respectively transmit detection light and receive light reflected / refracted by the transparent lens 3. The basic optical interaction for liquid level detection is achieved through the transmission and reception of optical signals. One end of the sleeve 7 is fixed axially to the end of the optical carrier plate 6 away from the transmitter 4. The air outlet 8 connects the optical carrier plate 6 and the sleeve 7, facilitating the introduction of airflow to cool the sensing components and remove water droplets, mist, or dust from the lens surface. The waterproof membrane further reduces the interference of trace amounts of liquid on the optical path.

[0047] See Figure 4 and Figure 5 In one embodiment, a motor 9 is provided along the inner axial direction of the sleeve 7, and a fan 10 is driven to the output end of the motor 9. The motor 9 is connected to the inner wall of the sleeve 7 through a connecting rod 11, and the axes of the sleeve 7, the motor 9 and the fan 10 coincide.

[0048] Specifically, one end of the connecting rod 11 is fixedly connected to the housing of the motor 9, and the other end is fixedly connected to the sleeve 7, thus supporting the motor 9. The fixed end of the motor 9 is connected to the output end of the fan 10. The motor 9 provides driving force, causing the fan 10 to rotate around its own axis, generating directional airflow. Because the axes of the three are coincident, the airflow generated by the rotation of the fan 10 flows stably along the axial direction of the sleeve 7, avoiding airflow turbulence caused by deflection. The sleeve 7 serves as an airflow channel, guiding the airflow generated by the fan 10 towards the optical carrier plate 6, and then directing it towards the surface of the transparent lens 3 through the air outlet 8 of the annular array in the middle of the optical carrier plate 6, in order to remove water droplets, fog, dust and other interference from the surface of the transparent lens 3, thereby improving the accuracy and long-term reliability of liquid level detection.

[0049] In one embodiment, the motor 9 has a cross plate 12 at the end away from the fan 10, and a plurality of heating wires 13 are wound at equal intervals along the length of the cross plate 12. The end of the cross plate 12 away from the motor 9 has a gap with the optical carrier plate 6.

[0050] Specifically, the fixed end of the motor 9 is connected to the cross plate 12 to support the cross plate 12. The cross plate 12 serves as the mounting carrier for the heating wire 13. Its cross structure not only fixes the heating wire 13 but also provides a channel for airflow (without blocking the airflow path inside the sleeve 7). Furthermore, due to the gap between it and the optical carrier plate 6, it ensures that the heated airflow can flow smoothly to the air outlet 8 of the optical carrier plate 6. When the heating wire 13 is energized, it generates heat, which heats the airflow inside the sleeve 7. When the airflow driven by the fan 10 flows through the heating wire 13, its temperature rises, forming a hot airflow. The hot airflow is directed through the air outlet 8 of the optical carrier plate 6 into the interior of the transparent lens 3, thereby achieving the effect of defogging and removing water droplets.

[0051] In one embodiment, a humidity sensor 14 and a temperature sensor 15 are mounted on the side of the optical carrier plate 6 away from the sleeve 7, and the humidity sensor 14 and the temperature sensor 15 are positioned away from the air outlet 8.

[0052] Specifically, the humidity sensor 14 and temperature sensor 15 monitor the humidity and temperature signals inside the transparent lens 3 in real time, forming a closed-loop control with the motor 9 and heating wire 13. When the humidity is too high, the heating wire 13 and motor 9 start, and the fan 10 generates hot airflow to achieve dehumidification and defogging effects; when the temperature is too high, the motor 9 starts, the heating wire 13 stops working, and the fan 10 generates cold airflow to reduce the temperature inside the transparent lens 3, protecting the sensor components and extending the service life of the device.

[0053] See Figure 6 In one embodiment, the end cover plate 17 of the sleeve 7 away from the optical carrier plate 6 has a plurality of air inlet and outlet holes 168 arranged in a ring. A wire harness 18 is provided at the axis of the cover plate 17, and the wire harness 18 is arranged to avoid the air inlet and outlet holes 168. A connector 19 is provided at the end of the wire harness 18 away from the sleeve 7. The transmitter 4, receiver 5, humidity sensor 14 and temperature sensor 15 are electrically connected to the connector 19 through the wire harness 18.

[0054] Specifically, the air inlet and outlet holes 168 of the ring array are matched with the airflow path inside the sleeve 7, providing a stable air supply to the inside of the sleeve 7. The wiring harness 18 is located on the axis of the cover plate 17 and avoids the air inlet and outlet holes 168. On the one hand, it concentrates the cables of the transmitter 4, receiver 5, and temperature and humidity sensor 14 into a bundle, preventing the cables from being loose and interfering with airflow or getting tangled with internal components (such as the fan 10). On the other hand, it protects the cable insulation layer by neatly wiring the cables, reducing the risk of wear. The connector 19 serves as an external interface, realizing convenient electrical connection (including power supply and signal transmission) between the sensor and the external control system. This allows the optical signal and temperature and humidity data of the detection module 2 to be output efficiently, while external control commands (such as adjusting the speed of the motor 9 and the power of the heating wire 13) can be accurately transmitted, ensuring stable and reliable electrical interaction of the entire system.

[0055] Example 3:

[0056] See Figure 2 and Figure 6 Based on the above embodiments, in one scheme, the outer periphery of the optical carrier plate 6 and the cover plate 17 is provided with a connecting ring 20, and the outer periphery of the connecting ring 20 is provided with an external thread 21 that matches the internal thread of the housing 1, so that the detection module 2 is threadedly connected to the housing 1.

[0057] Specifically, the detection module 2 is threadedly connected to the housing 1 by matching the external thread 21 of the connecting ring 20 with the internal thread of the housing 1, thereby enabling quick installation and disassembly of the detection module 2 and the housing 1. The tightness of the threaded connection, together with the sealing ring (such as an O-ring) between the housing 1 and the connecting ring 20, forms a radial seal, preventing external liquids or moisture from entering the interior of the housing 1 through the connection gap, thus protecting the circuitry and optical components of the detection module 2. The shape and size of the connecting ring 20 match the internal structure and dimensions of the housing 1 to ensure proper installation of the detection module.

[0058] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. Although embodiments of this utility model have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this utility model. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this utility model.

Claims

1. An optoelectronic liquid level sensor, characterized in that include: case; A detection module is threadedly connected to the housing. A transparent lens is provided at one axial end of the housing, and the transparent lens is covered with a waterproof membrane along its outer wall; The transparent lens has a conical structure, which allows the light emitted by the detection module to form a continuous gradient of incident angle distribution when it is incident on its surface, through the curved surface characteristics.

2. The photoelectric liquid level sensor according to claim 1, characterized in that, The detection module includes: The optical carrier includes a transmitter and a receiver mounted on an optical carrier plate. A sleeve is connected to the end of the optical carrier plate away from the transmitter. The optical carrier plate has several air outlets arranged in a ring in the middle to allow the optical carrier plate and the sleeve to communicate with each other.

3. The photoelectric liquid level sensor according to claim 2, characterized in that, A motor is provided along the inner axial direction of the sleeve, and a fan is driven to the output end of the motor. The motor is connected to the inner wall of the sleeve through a connecting rod, and the axes of the sleeve, the motor and the fan coincide.

4. The photoelectric liquid level sensor according to claim 3, characterized in that, The motor has a cross-shaped plate at the end away from the fan, and several heating wires are wound at equal intervals along the length of the cross-shaped plate. The end of the cross-shaped plate away from the motor has a gap with the optical carrier plate.

5. The photoelectric liquid level sensor according to claim 4, characterized in that, A humidity sensor and a temperature sensor are installed on the side of the optical carrier plate away from the sleeve, and the humidity sensor and temperature sensor are positioned away from the air outlet.

6. The photoelectric liquid level sensor according to claim 5, characterized in that, The sleeve has a ring array of several air inlet and outlet holes on the end cover plate away from the optical carrier plate. A wire harness is provided at the center of the cover plate, and the wire harness is arranged to avoid the air inlet and outlet holes. A connector is provided at the end of the wire harness away from the sleeve. The transmitter, receiver, humidity sensor and temperature sensor are electrically connected to the connector through the wire harness.

7. The photoelectric liquid level sensor according to claim 6, characterized in that, The outer periphery of the optical carrier plate and the cover plate is provided with a connecting ring, and the outer periphery of the connecting ring is provided with an external thread that matches the internal thread of the housing, so that the detection module is threadedly connected to the housing.

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