Total reflection type photoelectric liquid level sensor

Abstract

The invention provides a total reflection type photoelectric liquid level sensor, which comprises a shell, a first cavity, a second cavity and a liquid level sensor, the optical lens is installed in the shell, stretches across the first cavity and the second cavity and is located between the transmitting module and the to-be-detected pipeline and between the receiving module and the to-be-detected pipeline; the control module is connected with the transmitting module and the receiving module and used for driving the transmitting module to output the optical signal towards the to-be-detected pipeline, receiving the electric signal output by the receiving module and determining a detection result according to the electric signal, and the detection result comprises whether liquid exists in the to-be-detected pipeline or not. The beneficial effects of the invention are that based on the principle of total reflection of light, high-precision and non-contact detection of the existence state of the liquid in the to-be-detected pipeline is realized, the unique design enables light emission and receiving to be completed on the same side of the pipeline, matching according to the pipe diameter size of the pipeline is not needed, the production cost is reduced, and the flexibility, universality and versatility of the sensor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric liquid level detection, and in particular to a total reflection type photoelectric liquid level sensor. Background Art

[0002] The photoelectric liquid level sensor is an efficient and accurate means of liquid level measurement and control. Its core principle is to use the reflection and refraction of light at the interface between two different media to measure and control the liquid level in the pipe to be measured. It plays a vital role in industrial automation and medical fields.

[0003] Most traditional photoelectric level sensors adopt a through-beam design. Their working principle is based on the refraction of the emitted light in the tube wall and the liquid. The receiving tube is used to measure and compare the intensity of the light reflected back through the lens under two different conditions (with or without liquid). Figure 1a-1b As shown, when there is liquid in the pipe 4 to be tested, the refraction path of the emitted light in the liquid is different from that when there is only the pipe wall (ie, no liquid), resulting in a change in the intensity of the reflected light. The sensor 100 determines whether there is liquid in the pipe 4 to be tested based on this change.

[0004] To further improve the signal / noise ratio, such as Figure 2a-2c As shown, the existing photoelectric liquid level sensor 300 also uses an optical structure (such as lens 301 and lens 302) to limit the light path, thereby increasing the signal ratio between the presence of liquid and the absence of liquid in the pipe 4 to be tested, thereby enhancing the detection sensitivity and accuracy.

[0005] However, since both types of photoelectric liquid level sensors rely on the refraction effect between the pipe wall and the liquid, there are certain requirements for the position of the transmitting tube and the receiving tube, as well as the overall shape of the sensor. This design constraint limits the universality of the sensor to different diameters of the pipes 4 to be tested. In practical applications, in order to adapt to different sizes of pipes 4 to be tested, it is often necessary to customize sensors of different designs, which not only increases the production cost, but also reduces the flexibility and versatility of the sensor. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a total reflection type photoelectric liquid level sensor.

[0007] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0008] A total reflection type photoelectric liquid level sensor, comprising:

[0009] A housing, wherein the housing has a first chamber and a second chamber, the first chamber is provided with a transmitting module, and the second chamber is provided with a receiving module;

[0010] An optical lens is installed in the housing, the optical lens spans the first chamber and the second chamber, and is located between the transmitting module and the pipeline to be tested and between the receiving module and the pipeline to be tested;

[0011] The control module is connected to the transmitting module and the receiving module respectively, and is used to drive the transmitting module to output an optical signal toward the pipeline to be tested, and receive the electrical signal output by the receiving module, and determine the detection result according to the electrical signal, and the detection result includes whether there is liquid in the pipeline to be tested.

[0012] Preferably, the light receiving end of the receiving module is arranged toward the pipeline to be tested to receive the reflected light signal after the light signal is sequentially transmitted through the optical lens, reflected by the pipeline to be tested and transmitted through the optical lens, and generate the electrical signal according to the reflected light signal.

[0013] Preferably, the receiving module is a multi-pixel receiving tube;

[0014] The control module comprises:

[0015] A signal processing unit, used to determine light distribution information of the reflected light signal received by the receiving module in the multi-pixel receiving tube according to the electrical signal;

[0016] The detection unit is connected to the signal processing unit and is used to determine whether there is liquid in the pipeline to be detected according to the light distribution information, and output the determination result including the determination result.

[0017] Preferably, the light distribution information includes any one or more combinations of light intensity and distribution information, light spot position, light spot centroid position, and light spot centroid position change information.

[0018] Preferably, the detection unit comprises:

[0019] A first judgment subunit is used to output a first detection result of determining that there is no liquid in the pipeline to be tested when the light distribution information indicates that the electrical signal is received;

[0020] A second judgment subunit is used to output a second detection result of determining whether liquid exists in the pipeline to be tested when the light distribution information indicates that the electrical signal is not received;

[0021] The detection result includes the first detection result or the second detection result.

[0022] Preferably, it also includes:

[0023] A power module connected to the control module;

[0024] The communication module is connected to the power module.

[0025] Preferably, it further comprises: a contact surface that fits with the surface of the pipeline to be tested, and the contact surface is a plane.

[0026] Preferably, a transparent protective layer is provided between the optical lens and the pipeline to be tested.

[0027] Preferably, the transparent protective layer is made of transparent silicone material or transparent acrylic material.

[0028] Preferably, the housing is a light-proof housing.

[0029] The advantages or beneficial effects of the technical solution of the present invention are:

[0030] The photoelectric liquid level sensor of the present invention is based on the principle of total reflection of light, and realizes high-precision, non-contact detection of the state of liquid in the pipeline to be tested. Its unique design enables the emission and reception of light to be completed on the same side of the pipeline, without the need to match according to the pipeline diameter, thereby reducing production costs and improving the flexibility, universality and versatility of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1a It is a schematic diagram of the optical path of a conventional through-beam photoelectric liquid level sensor in the prior art when there is no liquid;

[0032] Figure 1b It is a schematic diagram of the optical path of a conventional through-beam photoelectric liquid level sensor in the prior art when there is liquid;

[0033] Figure 2a It is a schematic diagram of the optical structure of a conventional through-beam photoelectric liquid level sensor in the prior art;

[0034] Figure 2b It is a schematic diagram of the optical path of a conventional through-beam photoelectric liquid level sensor in the prior art when there is no liquid;

[0035] Figure 2c It is a schematic diagram of the optical path of a conventional through-beam photoelectric liquid level sensor in the prior art when there is liquid;

[0036] Figure 3 It is a schematic cross-sectional diagram of the assembly of a total reflection type photoelectric liquid level sensor in a preferred embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the assembly cross-sectional structure of a total reflection type photoelectric liquid level sensor in a preferred embodiment of the present invention;

[0038] Figure 5 A top view of a total reflection type photoelectric liquid level sensor in a preferred embodiment of the present invention;

[0039] Figure 6 A side view of a total reflection type photoelectric liquid level sensor in a preferred embodiment of the present invention;

[0040] Figure 7 This is a principle block diagram of a total reflection type photoelectric liquid level sensor in a preferred embodiment of the present invention;

[0041] Figure 8 A schematic diagram of a control module in a preferred embodiment of the present invention;

[0042] Fig. 9 This is a schematic diagram of the optical path when there is no liquid in a preferred embodiment of the present invention;

[0043] Fig.10 This is a diagram showing the total power distribution of light in the absence of liquid in a preferred embodiment of the present invention;

[0044] Fig.11 This is a schematic diagram of the optical path when there is liquid in a preferred embodiment of the present invention;

[0045] Fig.12 This is a diagram showing the total light power distribution when there is liquid in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0047] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0048] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0049] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a total reflection type photoelectric liquid level sensor is provided. Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, including:

[0050] A housing 1, wherein the housing 1 has a first chamber 11 and a second chamber 12, wherein the first chamber 11 is provided with a transmitting module 2, and wherein the second chamber 12 is provided with a receiving module 5;

[0051] An optical lens 3 is installed in the housing 1. The optical lens 3 spans the first chamber 11 and the second chamber 12, and is located between the transmitting module 2 and the pipe to be tested 4, and between the receiving module 5 and the pipe to be tested 4;

[0052] The control module 6 is connected to the transmitting module 2 and the receiving module 5 respectively, and is used to drive the transmitting module 2 to output an optical signal toward the pipeline 4 to be tested, and to receive the electrical signal output by the receiving module 5, and to determine the detection result according to the electrical signal, and the detection result includes whether there is liquid in the pipeline 4 to be tested.

[0053] Specifically, in this embodiment, the transmitting module 2 and the receiving module 5 are both located on the same side of the pipe to be tested 4, and are respectively integrated in two independent spaces in the housing 1 - the first chamber 11 and the second chamber 12, thereby ensuring the optical separation of the transmitting and receiving processes and improving the stability and reliability of the sensor.

[0054] The optical lens 3 is installed inside the housing 1, and its position spans the two chambers. It is located between the transmitting module 2 and the pipe to be tested 4, and also between the receiving module 5 and the pipe to be tested 4. It can guide the light signal emitted by the transmitting module 2 to be accurately projected onto the surface of the pipe to be tested 4, and can also collect the light signal reflected from the pipe to be tested 4 and guide it to the receiving module 5.

[0055] The control module 6 is electrically connected to the transmitting module 2 and the receiving module 5, and is responsible for sending instructions to the transmitting module 2. The transmitting tube 21 of the transmitting module 2 transmits an optical signal synchronized with the signal processing of the receiving tube under the driving control of the instruction. The optical signal is transmitted to the pipeline 4 to be tested through the optical lens 3. At the same time, the electrical signal from the receiving module 5 is received. The electrical signal is converted by the receiving module 5 according to the received optical signal. By processing these electrical signals, it is analyzed and judged whether there is liquid inside the pipeline 4 to be tested.

[0056] Specifically, according to the total reflection principle, if there is no liquid inside the pipeline to be tested, then all or most of the optical signal will be reflected back to the receiving module 5 .

[0057] On the contrary, if there is liquid inside the pipe to be tested, the optical signal will be partially refracted at the interface between the liquid and the pipe wall, causing the intensity of the reflected optical signal to be greatly reduced, or even unable to be effectively received by the receiving module 5 .

[0058] The control module 6 utilizes the signal difference between the two situations to accurately determine whether there is liquid inside the pipeline 4 to be tested by comparing the electrical signal strength or the presence or absence of a signal output by the receiving module 5. The detection method based on the total reflection principle is simple and reliable, and has high sensitivity, accuracy and reliability.

[0059] In this embodiment, the pipeline to be tested 4 may be a transparent pipeline to be tested.

[0060] In this embodiment, the transmitting module 2 and the receiving module 5 are arranged along the axial direction of the pipeline 4 to be tested, and are located on the same side of the pipeline to be tested.

[0061] In this embodiment, the transmitting module 2 and the receiving module 5 are integrated on a circuit board 10 .

[0062] As a preferred embodiment, the light receiving end of the receiving module 5 is arranged toward the pipe to be tested 4 to receive the light signal transmitted through the optical lens 3, reflected by the pipe to be tested 4 and reflected by the optical lens 3, and generate an electrical signal according to the reflected light signal.

[0063] Specifically, in this embodiment, the optical signal is first output from the transmitting tube, and then transmitted through the optical lens 3 to act on the inner wall or outer wall of the pipeline to be tested.

[0064] If there is no liquid inside the pipe to be tested, the light signal will be reflected on the wall, and all or most of the light signal will be transmitted through the same optical lens again to form a reflected light signal.

[0065] When there is liquid inside the pipe to be tested, the optical signal will be partially refracted at the interface between the liquid and the pipe wall, causing the intensity of the reflected optical signal to be greatly reduced, and may even make it impossible to be effectively received by the receiving module 5.

[0066] The receiving module 5 can capture the reflected light signal and generate a corresponding electrical signal using an internal photoelectric conversion mechanism.

[0067] The embodiment of the present invention utilizes the total reflection principle and the optical lens design to realize that when there is no liquid, the emitted light is fully reflected back to the receiving tube; when there is liquid, due to the refraction of the liquid, part of the light signal cannot return to the receiving tube. The strength of the signal received by the receiving tube can accurately determine whether there is liquid in the pipeline.

[0068] As a preferred embodiment, the receiving module 5 is a multi-pixel receiving tube;

[0069] like Figure 8 As shown, the control module 6 includes:

[0070] The signal processing unit 61 is used to determine the light distribution information of the reflected light signal received by the receiving module 5 in the multi-pixel receiving tube according to the electrical signal;

[0071] The detection unit 62 is connected to the signal processing unit 61 and is used to determine whether there is liquid in the pipeline to be detected according to the light distribution information, and output the determination result including the determination result in the detection result.

[0072] As a preferred implementation, the light distribution information includes any one or more combinations of light intensity and distribution information, light spot position, light spot centroid position, and light spot centroid position change information.

[0073] Specifically, in this embodiment, the control module 6 can analyze the light distribution information of the reflected light signal on the multi-pixel receiving tube according to the electrical signal from the receiving module 5, including but not limited to light intensity and distribution information, light spot position, light spot centroid position, and light spot centroid position change information. Subsequently, by analyzing the light distribution information, it is determined whether there is liquid inside the pipeline to be tested.

[0074] As a preferred embodiment, the detection unit 62 includes:

[0075] The first judging subunit 621 is used to output a first detection result of judging that there is no liquid in the pipeline to be tested when the light distribution information indicates that the electric signal is received;

[0076] The second judging subunit 622 is used to output a second detection result of judging whether liquid exists in the pipeline to be tested when the light distribution information indicates that no electric signal is received;

[0077] The detection result includes a first detection result or a second detection result.

[0078] Specifically, when the light distribution information indicates that a clear electrical signal is received, that is, the light signal is totally reflected by the pipe wall and successfully captured by the receiving module 5, the detection unit 62 will output a first detection result, that is, it is determined that there is no liquid in the pipe to be tested.

[0079] On the contrary, if the light distribution information shows that the expected electrical signal is not received, it means that the light signal is refracted at the junction of the liquid and the pipe wall, causing the intensity of the reflected light signal to weaken or disappear. At this time, the detection unit 62 will output a second detection result, that is, it is determined that there is liquid in the pipe to be tested.

[0080] Furthermore, after the photoelectric liquid level sensor of the present invention is installed on the pipe to be tested 4, under the control of the control module 6, the emission light intensity and the sensor channel gain are adjusted so that the receiving tube outputs a first voltage value VL when there is liquid in the pipe to be tested 4, and outputs a second voltage value VH when there is no liquid in the pipe to be tested 4.

[0081] Specifically, the voltage difference (VH-VL) between the first voltage value VL and the second voltage value VH satisfies a certain difference. The difference setting can be achieved by a button or a non-contact Hall switch or a teaching line. Before leaving the factory, the configuration of the sensor can be set according to the specific pipeline 4 to be tested for user use.

[0082] like Fig. 9 and Fig.10As shown, if there is no liquid in the pipeline, the light signal emitted from the transmitting tube passes through the optical lens and the tube wall in sequence, and is totally reflected back to the receiving tube, forming a first voltage value VL on the receiving tube.

[0083] like Fig.11 and Fig.12 As shown, if there is liquid in the pipeline, the light signal emitted by the transmitting tube passes through the optical lens, the pipe wall and the liquid in sequence. Since the liquid refracts part of the light, the voltage value on the receiving tube is smaller than the case where there is no liquid in the pipeline 4 to be tested, and the voltage value is VL.

[0084] The embodiment of the present invention uses the voltage on the receiving tube when there is liquid or no liquid in the pipeline to determine the liquid level state in the pipeline 4 to be measured. Due to the principle of total reflection, the signal difference is large when there is liquid and when there is no liquid, thus improving the reliability of liquid level measurement.

[0085] In addition, the sensor does not need to adjust the transmitting / receiving position according to the size of the pipeline 4 to be tested, and can be applied to pipelines 4 to be tested in different shapes, which greatly improves the applicability of the sensor.

[0086] Furthermore, the second judging subunit 622 may also output a second detection result for judging the presence of liquid in the pipeline to be tested when the light intensity decreases.

[0087] As a preferred embodiment, the invention further comprises:

[0088] A power module 7 connected to the control module 6;

[0089] The communication module 8 is connected to the power module 7.

[0090] Specifically, the power module 7 is used to provide power for the entire sensor; the communication module 8 is used to communicate data with an external device (such as a computer or a control system), including but not limited to receiving instructions, feeding back data, and the like.

[0091] Furthermore, the optical lens 3 is a plano-convex lens. The plane side of the plano-convex lens is arranged toward the pipeline, and the convex side is arranged away from the pipeline, so as to ensure that after the light is emitted, it can be refracted by the plano-convex lens and can be more concentratedly directed to the pipeline surface, and total reflection occurs when there is no liquid in the pipeline, effectively guiding the reflected light signal back to be received, improving the transmission efficiency and receiving sensitivity of the optical signal, thereby enhancing the accuracy and reliability of liquid level detection.

[0092] The optical lens 3 is made of polymethyl methacrylate (PMMA). The PMMA lens, with its high transparency, good optical properties and weather resistance, ensures accurate transmission and reception of optical signals and improves the accuracy and stability of liquid level detection.

[0093] As a preferred embodiment, it further comprises: a contact surface that fits with the surface of the pipeline 4 to be tested, and the contact surface is a plane.

[0094] Specifically, the side of the sensor that fits the pipe 4 to be tested can be a flat surface, which is directly attached to the outer surface of the pipe 4 to be tested. There is no need to customize sensors with different curved surfaces according to the sizes of different pipes, and there is no need to adjust the transmitting / receiving position according to the size of the pipe. This greatly simplifies the installation process and reduces the manufacturing cost. It is suitable for pipes 4 to be tested in different shapes, and greatly improves the applicability and flexibility of the sensor.

[0095] At the same time, the flat contact surface also ensures the stable transmission of optical signals and avoids the problem of optical signal distortion caused by the curved surface.

[0096] As a preferred embodiment, a transparent protective layer 9 is provided between the optical lens 3 and the pipeline to be measured 4 .

[0097] Specifically, in this embodiment, by providing a transparent protective layer 9 between the optical lens 3 and the pipeline to be tested 4, the optical lens can be effectively prevented from being damaged due to direct contact with the pipeline, and at the same time, the interference of environmental factors (such as dust, water vapor, etc.) on the optical signal transmission can be reduced.

[0098] As a preferred embodiment, the transparent protective layer 9 is made of transparent silicone material or transparent acrylic material.

[0099] Specifically, in this embodiment, the transparent protective layer 9 is made of transparent silicone material or transparent acrylic material. Both materials have good transparency and weather resistance, and can effectively protect the optical lens 3 from erosion by the external environment while ensuring smooth transmission of optical signals.

[0100] Furthermore, a fixing device may be provided to ensure that the sensor of the present invention is in close contact with the pipeline 4 to be measured.

[0101] As a preferred embodiment, the housing 1 is a light-proof housing.

[0102] Specifically, in this embodiment, the sensor circuit and optical lens 3 are located in the housing 1. The light-proof housing wraps and protects the electronic components and optical components inside the sensor, which can effectively prevent external light from interfering with the internal optical signal of the sensor, thereby improving the overall aesthetics and durability of the sensor.

[0103] Preferably, the housing is made of black light-proof material.

[0104] The advantages or beneficial effects of adopting the above technical solution are: the photoelectric liquid level sensor of the present invention is based on the principle of total reflection of light, and realizes high-precision, non-contact detection of the state of liquid in the measured pipeline. Its unique design enables the emission and reception of light to be completed on the same side of the pipeline, and there is no need to match it according to the pipeline diameter, which reduces the production cost and improves the flexibility, universality and versatility of the sensor.

[0105] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A total reflection type photoelectric liquid level sensor, characterized in that: include: A housing, wherein the housing has a first chamber and a second chamber, the first chamber is provided with a transmitting module, and the second chamber is provided with a receiving module; An optical lens is installed in the housing, the optical lens spans the first chamber and the second chamber, and is located between the transmitting module and the pipeline to be tested and between the receiving module and the pipeline to be tested; The control module is connected to the transmitting module and the receiving module respectively, and is used to drive the transmitting module to output an optical signal toward the pipeline to be tested, and receive the electrical signal output by the receiving module, and determine the detection result according to the electrical signal, and the detection result includes whether there is liquid in the pipeline to be tested.

2. The photoelectric liquid level sensor according to claim 1, characterized in that: The optical receiving end of the receiving module is arranged toward the pipeline to be tested to receive the reflected light signal of the optical signal after being sequentially transmitted through the optical lens, reflected by the pipeline to be tested and transmitted through the optical lens, and generate the electrical signal according to the reflected light signal.

3. The photoelectric liquid level sensor according to claim 1, characterized in that: The receiving module is a multi-pixel receiving tube; The control module comprises: A signal processing unit, used to determine light distribution information of the reflected light signal received by the receiving module in the multi-pixel receiving tube according to the electrical signal; The detection unit is connected to the signal processing unit and is used to determine whether there is liquid in the pipeline to be detected according to the light distribution information, and output the determination result including the determination result.

4. The photoelectric liquid level sensor according to claim 3, characterized in that: The light distribution information includes any one or more combinations of light intensity and distribution information, light spot position, light spot centroid position, and light spot centroid position change information.

5. The photoelectric liquid level sensor according to claim 3, characterized in that: The detection unit comprises: A first judgment subunit is used to output a first detection result of determining that there is no liquid in the pipeline to be tested when the light distribution information indicates that the electrical signal is received; A second judgment subunit is used to output a second detection result of determining whether liquid exists in the pipeline to be tested when the light distribution information indicates that the electrical signal is not received; The detection result includes the first detection result or the second detection result.

6. The photoelectric liquid level sensor according to claim 1, characterized in that: Also includes: A power module connected to the control module; The communication module is connected to the power module.

7. The photoelectric liquid level sensor according to claim 1, characterized in that: Also includes: A contact surface that fits the surface of the pipeline to be tested, wherein the contact surface is a plane.

8. The photoelectric liquid level sensor according to claim 1, characterized in that: A transparent protective layer is provided between the optical lens and the pipeline to be tested.

9. The photoelectric liquid level sensor according to claim 8, characterized in that: The transparent protective layer is made of transparent silicone material or transparent acrylic material.

10. The photoelectric liquid level sensor according to claim 1, characterized in that: The shell is a light-proof shell.

Images