Photoelectric sensor

Abstract

The invention provides a photoelectric sensor, and belongs to the technical field of photoelectric sensing, and the photoelectric sensor comprises a transmitting module which is used for outputting an optical signal under the action of an optical driving signal; the receiving module and the transmitting module are oppositely arranged on the two sides of the to-be-detected pipeline, and the receiving module comprises a multi-pixel receiving tube and is used for receiving a transmission light signal obtained after the light signal passes through the to-be-detected pipeline and generating an electric signal; and the control module is used for outputting a light driving signal, determining voltage distribution information of the transmission light signal on the multi-pixel receiving tube according to the electric signal, and determining whether liquid exists in the to-be-detected pipeline, whether bubbles exist in the liquid and the sizes of the bubbles according to the voltage distribution information. The photoelectric sensor disclosed by the invention has the beneficial effects that the photoelectric sensor integrates multiple functions, can monitor whether liquid exists in a pipeline, whether bubbles exist in the liquid and the sizes of the bubbles at the same time, has the advantage of high reliability, can replace the existing photoelectric liquid level and photoelectric bubble sensor, and is widely applied to industrial automatic control.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric sensing technology, and in particular to a photoelectric sensor. Background Art

[0002] At present, the measurement of the presence / absence of liquid in a pipeline and the presence / absence of bubbles in a liquid is usually completed by two independent sensors, namely, photoelectric liquid level detection sensors and photoelectric bubble detection sensors. For example, Omron E2K series photoelectric liquid level sensors are specially used for liquid level detection in pipelines, and Panasonic BE-A series photoelectric bubble sensors are specially used for bubble detection in pipelines.

[0003] The working principle of these two sensors is based on the optical principle, that is, by emitting light and measuring the intensity change after it is reflected or refracted by the medium (liquid or bubbles) in the pipeline, the liquid state in the pipeline is determined. Specifically, when there is liquid in the pipeline, the reflection or refraction characteristics of the liquid to light are completely different from when the pipeline is empty; similarly, bubbles mixed in the liquid will significantly change the propagation path and intensity of the light. The photoelectric receiving tube is responsible for capturing these changes and converting them into electrical signals for further analysis.

[0004] However, the intensity of reflected or refracted light is easily affected by a variety of external factors, such as bubble size, tube wall thickness and cleanliness, liquid color and reflective / refractive index. Due to the existence of these interfering factors, the signal output by the sensor will fluctuate greatly, increasing the risk of misjudgment. Especially in some application scenarios with extremely high detection accuracy requirements, such as infusion pump systems, existing sensors cannot detect tiny bubbles and fast-moving bubbles. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a photoelectric sensor.

[0006] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0007] A photoelectric sensor, comprising:

[0008] A transmitting module, used for outputting an optical signal under the action of an optical driving signal;

[0009] A receiving module, the receiving module and the transmitting module are arranged on both sides of the pipeline to be tested, the receiving module includes a multi-pixel receiving tube, which is used to receive the transmitted light signal of the light signal after passing through the pipeline to be tested, and generate an electrical signal according to the transmitted light signal;

[0010] The control module is respectively connected to the transmitting module and the receiving module, and is used to output the light driving signal, and determine the voltage distribution information of the transmitted light signal on the multi-pixel receiving tube according to the electrical signal, and determine whether there is liquid in the pipeline to be tested and whether there are bubbles in the liquid and the size of the bubbles according to the voltage distribution information.

[0011] Preferably, the voltage distribution information includes one or more combinations of light spot intensity, light spot size, light spot position, light intensity of each pixel receiving tube / ratio of light intensity / position change of the centroid of the light spot.

[0012] Preferably, the control module comprises:

[0013] The liquid level detection unit is used to determine that there is no liquid in the pipeline to be tested when the voltage distribution information is uniformly distributed; and to determine that there is liquid in the pipeline to be tested when the voltage distribution information is Gaussian distributed.

[0014] Preferably, the control module further includes:

[0015] The bubble detection unit is used to determine that there is liquid in the pipeline to be tested and there are bubbles in the liquid when the voltage distribution information is distributed in an inverted trapezoidal shape.

[0016] Preferably, the voltage distribution information at least includes first voltage distribution information corresponding to the first bubble and second voltage distribution information corresponding to the second bubble;

[0017] The bubble detection unit is further used to compare the first voltage distribution information with the second voltage distribution information to determine the size of the bubble.

[0018] Preferably, the size of the bubble is inversely proportional to the voltage value in the voltage distribution information.

[0019] Preferably, the control module is further used to determine the change information of the voltage distribution of the transmitted light signal on the multi-pixel receiving tube over time according to the electrical signal, and determine the moving speed of the bubble according to the change information.

[0020] Preferably, the control module further includes:

[0021] The bubble movement speed determination unit is used to determine the voltage change rate according to the voltage distribution change information over time, and determine the bubble movement speed according to the voltage change rate.

[0022] Preferably, the multi-pixel receiving tube is parallel to the axial direction of the pipeline to be tested; or

[0023] The multi-pixel receiving tube is perpendicular to the axial direction of the pipeline to be tested.

[0024] Preferably, it also includes:

[0025] A power module connected to the control module;

[0026] The communication module is connected to the power module.

[0027] The advantages or beneficial effects of the technical solution of the present invention are:

[0028] The photoelectric sensor of the present invention integrates multiple functions and can simultaneously monitor the presence of liquid in the pipeline, the presence of bubbles in the liquid and the size of the bubbles. It has the advantage of high reliability and can replace existing photoelectric liquid level and photoelectric bubble sensors and is widely used in industrial automation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A structural block diagram of a photoelectric sensor in a preferred embodiment of the present invention;

[0030] Figure 2 This is a voltage distribution diagram when there is no liquid in the pipeline to be tested in a preferred embodiment of the present invention;

[0031] Figure 3 In a preferred embodiment of the present invention, a voltage distribution diagram of a liquid in a pipeline to be tested;

[0032] Figure 4 This is a voltage distribution diagram of a preferred embodiment of the present invention when there are bubbles in the liquid;

[0033] Figure 5 The voltage distribution diagram of different bubble sizes in the preferred embodiment of the present invention;

[0034] Figure 6 A line graph of voltage distribution of different bubble sizes in a preferred embodiment of the present invention;

[0035] Figure 7 A voltage distribution diagram when the bubbles move in a preferred embodiment of the present invention;

[0036] Figure 8 This is a voltage distribution curve diagram when the bubble moves 0.2 mm in a preferred embodiment of the present invention;

[0037] Fig. 9 This is a voltage distribution curve diagram when the bubble moves 0.4 mm in a preferred embodiment of the present invention;

[0038] Fig.10 This is a voltage distribution curve diagram when the bubble moves 0.6 mm in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a photoelectric sensor is provided. Figure 1 As shown, including:

[0043] Transmitter module 1, used to output an optical signal under the action of an optical drive signal;

[0044] The receiving module 2 is arranged on both sides of the pipeline to be tested opposite to the transmitting module 1. The receiving module 2 includes a multi-pixel receiving tube 21, which is used to receive the transmitted light signal of the light signal after passing through the pipeline to be tested, and generate an electrical signal according to the transmitted light signal;

[0045] The control module 3 is connected to the transmitting module 1 and the receiving module 2 respectively, and is used to output a light driving signal, and determine the voltage distribution information of the transmitted light signal on the multi-pixel receiving tube 21 according to the electrical signal, and determine whether there is liquid in the pipeline to be tested and whether there are bubbles in the liquid and the size of the bubbles according to the voltage distribution information.

[0046] Specifically, the photoelectric sensor proposed in the present invention is composed of a transmitting module 1, a receiving module 2 and a control module 3. The receiving module 2 is implemented by a multi-pixel receiving tube 21. The transmitting tube of the transmitting module 1 transmits a light signal synchronized with the multi-pixel receiving tube 21 under the action of the light driving signal output by the control module 3. The multi-pixel receiving tube 21 receives the signal of the transmitting tube. By using the signal received by the multi-pixel receiving tube 21, the detection of whether there is liquid in the pipeline to be tested, the presence or absence of bubbles in the liquid in the pipeline to be tested, and the size of the bubbles can be realized at the same time.

[0047] There are three typical states of the pipeline to be tested in actual work: no liquid, liquid (no bubbles) and bubbles in the liquid.

[0048] like Figure 2As shown, when there is no liquid in the pipeline, the emitted light will directly pass through the air in the pipeline. Since air has no focusing effect on light, the voltage values ​​of each tube received on the multi-pixel receiving tube 21 are completely different from the situation where there is liquid or liquid containing bubbles in the pipeline; similarly, the distribution of each tube voltage presents a certain shape, which is also completely different from the situation where there is liquid or liquid containing bubbles in the pipeline.

[0049] like Figure 3 As shown, if the pipe is full of liquid, the emitted light passes through the liquid, which is equivalent to being focused by the lens. Therefore, the voltage of each tube on the multi-pixel receiving tube 21 is much greater than the case without liquid, and the distribution of each tube voltage is also different from the case when there is no liquid or bubbles in the pipe.

[0050] like Figure 4 As shown, if there is bubble-containing liquid in the pipeline, the voltages of each tube on the multi-pixel receiving tube 21 are related to the size of the bubbles and are different from the situation where there is no liquid or bubble-free liquid in the pipeline; and the distribution of each tube voltage is also different from the situation where there is no liquid or bubble-free liquid in the pipeline.

[0051] The voltage distribution on each tube of the multi-pixel receiving tube 21 is related to the size of the bubble. Figure 5 , Figure 6 and Figure 7 As shown, as the position of the bubble changes, the voltage distribution also changes with the change of the bubble position. Therefore, the movement speed and size of the bubble can be determined by the voltage distribution on the multi-pixel receiving tube 21.

[0052] The present invention utilizes multiple parameters such as the voltage, voltage distribution, and change in voltage distribution on the multi-pixel receiving tube 21 in these three situations to determine whether there are bubbles / liquid in the pipeline, further improving the reliability of the photoelectric sensor used to detect bubbles / liquid levels, and the same sensor can be used to achieve the measurement functions of whether there is liquid in the pipeline and whether there are bubbles in the liquid in the pipeline.

[0053] The embodiment of the present invention takes the installation method of the multi-pixel receiving tube 21 being parallel to the pipeline and located at the center of the pipeline to be measured to form a corresponding photoelectric sensor as an example.

[0054] As a preferred embodiment, the voltage distribution information includes one or more combinations of light spot intensity, light spot size, light spot position, light intensity of each pixel receiving tube / ratio of light intensity / position change of the center of mass of the light spot.

[0055] As a preferred embodiment, the control module 3 includes:

[0056] The liquid level detection unit is used to determine that there is no liquid in the pipeline to be tested when the voltage distribution information is uniformly distributed; and to determine that there is liquid in the pipeline to be tested when the voltage distribution information is Gaussian distributed.

[0057] Specifically, Figure 2 As shown, when there is no liquid in the pipeline, the emitted light will directly pass through the air in the pipeline. Since air has no focusing effect on light, the voltage value of each tube of the multi-pixel receiving tube 21 is significantly lower than the voltage value when there is liquid or liquid containing bubbles in the pipeline, and the voltage distribution on each pixel receiving tube is relatively uniform.

[0058] like Figure 3 As shown, when the pipe is full of liquid, the emitted light passes through the liquid in the pipe. Due to the focusing effect of the liquid, the voltage value of each tube increases significantly compared to when there is no liquid, and the distribution of voltage on each pixel is significantly different, presenting a Gaussian distribution approximately centered on the center of the pipe.

[0059] Therefore, the photoelectric sensor of the embodiment of the present invention can distinguish between two different states: the presence / absence of liquid in the pipeline.

[0060] As a preferred embodiment, the control module 3 further includes:

[0061] The bubble detection unit is used to determine that there is liquid in the pipeline to be tested and there are bubbles in the liquid when the voltage distribution information is distributed in an inverted trapezoidal shape.

[0062] Specifically, if there are bubbles in the liquid, the voltage distribution of each tube on the multi-pixel receiving tube 21 will be significantly different from the distribution when it is full of liquid / without liquid, depending on the size difference of these bubbles.

[0063] Due to the presence of bubbles, the voltage measured by the pixel receiving tube corresponding to the bubble will be much lower than the voltage value when the position is occupied by liquid. This makes the voltage distribution on the multi-pixel receiving tube 21 present an inverted trapezoidal distribution, which is completely different from the voltage distribution mode in the pure liquid or liquid-free state. Therefore, the photoelectric sensor of the present invention can accurately identify and determine the state of the presence of bubbles.

[0064] As a preferred embodiment, the voltage distribution information at least includes first voltage distribution information corresponding to the first bubble and second voltage distribution information corresponding to the second bubble;

[0065] The bubble detection unit is further used to compare the first voltage distribution information with the second voltage distribution information to determine the size of the bubble.

[0066] Specifically, Figure 4As shown, by adopting a multi-pixel receiving tube 21, the intensity, size, position of the light spot refracted / reflected on the multi-pixel receiving tube 21 by the pipeline (liquid or bubble), the light spot intensity, the light spot size, the light spot position, the light intensity / the ratio of the light intensity / the position change of the center of mass of the light spot of each receiving tube are monitored simultaneously to determine whether there are bubbles in the pipeline, thereby achieving high-precision and reliable measurement of pipeline liquid and bubbles in pipeline liquid, and judging the size of the bubbles.

[0067] The embodiment of the present invention greatly improves the reliability of the sensor, and the same sensor can be used to simultaneously measure whether there is liquid in the pipeline and whether there are bubbles in the liquid in the pipeline.

[0068] As a preferred implementation, the size of the bubble is inversely proportional to the voltage value in the voltage distribution information.

[0069] As a preferred embodiment, the control module 3 is further used to determine the change information of the voltage distribution of the transmitted light signal on the multi-pixel receiving tube 21 over time according to the electrical signal, and determine the moving speed of the bubble according to the change information.

[0070] As a preferred embodiment, the control module 3 further includes:

[0071] The bubble movement speed determination unit is used to determine the voltage change rate according to the voltage distribution change information over time, and determine the bubble movement speed according to the voltage change rate.

[0072] Furthermore, by measuring the time it takes for the light spot to pass through the multi-pixel receiving tube 21, the photoelectric sensor of the present invention can measure the speed at which the bubble passes through the sensor, thereby providing further measurement data for the system.

[0073] Furthermore, by measuring the size of the imaging of the light spot on the multi-pixel receiving tube 21, the photoelectric sensor of the present invention can measure the size / volume of the bubble passing through the sensor, providing further measurement data for the system.

[0074] Furthermore, the moving direction of the bubbles can also be determined.

[0075] As a preferred embodiment, the multi-pixel receiving tube 21 is parallel to the axial direction of the pipeline to be tested; or

[0076] The multi-pixel receiving tube 21 is perpendicular to the axial direction of the pipeline to be tested.

[0077] In this embodiment, the multi-pixel receiving tube 21 can be implemented by a multi-pixel CMOS distance measurement sensor chip.

[0078] It should be noted that the multi-pixel CMOS distance measuring sensor chip may adopt an existing chip, such as the programmable photoelectric sensor shown in CN114440943A, but is not limited thereto and the present invention does not make any limitation thereto.

[0079] As a preferred embodiment, the invention further comprises:

[0080] A power module 4, connected to the control module 33, for providing power to the entire sensor;

[0081] The communication module 5 is connected to the power module 4 and is used for data communication 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.

[0082] Example

[0083] In the above-mentioned preferred embodiment, a photoelectric sensor is provided which can judge three different situations: no liquid in the pipeline, liquid without bubbles, and liquid containing bubbles. It can also provide the bubble size / volume and bubble movement speed in the liquid at the same time. It can be widely used for liquid / bubble detection in liquid delivery systems in the industrial / medical industries.

[0084] Furthermore, take the example that the transmitting tube and the multi-pixel receiving tube 21 chip of the photoelectric sensor are installed on both sides of the pipeline to be tested, and the multi-pixel receiving tube 21 is parallel to the pipeline to be tested and located at the center of the pipeline to be tested to form a facing photoelectric sensor.

[0085] Install the liquid-free pipe to be tested on the pipe installation hole of the sensor. After installation, adjust the emission light intensity and sensor channel gain to make the photoelectric sensor work in a normal state.

[0086] By measuring the voltage and voltage distribution of each tube of the multi-pixel receiving tube 21 when the emitted light is in the absence of liquid, the voltage and voltage distribution are stored in the register of the control module 3 .

[0087] Different types of pipelines have different voltages and voltage distributions, so when the pipelines to be tested are different, the sensor needs to be recalibrated.

[0088] After the sensor calibration is completed, under the control of the control module 3, the photoelectric sensor monitors the characteristics of the light spot refracted / reflected by the pipeline to be tested on the multi-pixel receiving tube 21, including but not limited to the light spot intensity, light spot size, light spot position, the light intensity / light intensity ratio of each receiving tube and the change of the light spot centroid. These data are used to determine whether the changes of the light spot intensity, light spot size, light spot position, the light intensity / light intensity ratio of each receiving tube and the light spot centroid exceed the corresponding preset threshold value after in-depth analysis, and then accurately output the detection results of whether there is liquid in the pipeline, and whether there is bubble when there is liquid.

[0089] See also Figure 2 , Figure 3 and Figure 4 In the absence of liquid, the voltages of each tube received by the multi-pixel receiving tube 21 are monitored to determine the three states of the pipeline to be tested: no liquid, full of liquid, and liquid with bubbles.

[0090] See also Figure 2 ,When there is no liquid in the pipe, the light directly passes through the pipe wall, the voltage of each tube is the smallest among the three cases when there is no liquid in the pipe, and the voltage is distributed relatively evenly on each pixel;

[0091] See also Figure 3 When the pipe is filled with liquid, due to the focusing effect of the liquid, the voltage of each tube increases significantly compared to when there is no liquid, and the distribution of voltage on each pixel is obviously different (approximately a Gaussian distribution centered on the center of the pipe). Therefore, the sensor can distinguish between two different states: with and without liquid in the pipe.

[0092] See also Figure 4 When there are bubbles in the liquid, the distribution of the voltages of each tube is obviously different from the situation of being full of liquid / no liquid according to the size of the bubbles. Due to the existence of bubbles, the voltage of the pixel of the multi-pixel receiving tube 21 relative to the bubble is much lower than when the position of the bubble is liquid, making the voltage on the multi-pixel receiving tube 21 inverted trapezoidal distribution. This voltage distribution is obviously different from the situation of being full of liquid / no liquid. Therefore, the sensor can also determine the state of the presence of bubbles.

[0093] By monitoring the voltage distribution on the multi-pixel receiving tube 21 and the change of the voltage distribution over time, the present invention also realizes the function of measuring the size of the bubble and the moving speed of the bubble at the same time.

[0094] See also Figure 5 and Figure 6 , the voltage distribution on the multi-pixel receiving tube 21 reflects the size of the bubbles in the liquid.

[0095] See also Figures 7 to 10 , monitor the change of voltage distribution of the multi-pixel receiving tube 21 over time. This change is caused by the movement of bubbles, which corresponds to the change of voltage on the multi-pixel receiving tube 21. The rate of change corresponds to the speed of the bubble moving in the tube.

[0096] In the embodiment of the present invention, the presence or absence of liquid can be distinguished by light intensity, and the light intensity is higher when liquid is present. When bubbles are present, the size of the bubbles can be distinguished by the light spot distribution. Furthermore, the movement of the bubbles can also be distinguished by the light spot intensity distribution.

[0097] The advantages or beneficial effects of adopting the above technical solution are that the photoelectric sensor of the present invention not only realizes the simultaneous monitoring of the presence of liquid in the pipeline and the presence of bubbles in the liquid, but also realizes the monitoring of the size of the bubbles and the speed of bubble movement. It has the advantages of multi-function and high reliability, can replace the existing photoelectric liquid level and photoelectric bubble sensors, and is widely used in industrial automation control.

[0098] The above are only preferred embodiments of the present invention, and do not limit the implementation methods and protection scope of the present invention. For example, the installation position of the sensor relative to the pipeline can be optimized according to the application, and the optical axis of the sensor can be in the center of the pipeline or on the pipe wall of the pipeline. The multi-pixel receiving tube 21 can be parallel to the pipeline to be tested or perpendicular to the pipeline to be tested; the sensor installation form can be through reflection or diffuse reflection. For those skilled in the art, it should be able to realize that all solutions obtained by equivalent substitutions and obvious changes made using this specification and the illustrated content should be included in the protection scope of the present invention.

Claims

1. A photoelectric sensor, characterized in that: include: A transmitting module, used for outputting an optical signal under the action of an optical driving signal; A receiving module, the receiving module and the transmitting module are arranged on both sides of the pipeline to be tested, the receiving module includes a multi-pixel receiving tube, which is used to receive the transmitted light signal of the light signal after passing through the pipeline to be tested, and generate an electrical signal according to the transmitted light signal; The control module is respectively connected to the transmitting module and the receiving module, and is used to output the light driving signal, and determine the voltage distribution information of the transmitted light signal on the multi-pixel receiving tube according to the electrical signal, and determine whether there is liquid in the pipeline to be tested and whether there are bubbles in the liquid and the size of the bubbles according to the voltage distribution information.

2. The photoelectric sensor according to claim 1, characterized in that: The voltage distribution information includes one or more combinations of light spot intensity, light spot size, light spot position, light intensity of each pixel receiving tube / ratio of light intensity / position change of the centroid of the light spot.

3. The photoelectric sensor according to claim 1, characterized in that: The control module comprises: The liquid level detection unit is used to determine that there is no liquid in the pipeline to be tested when the voltage distribution information is uniformly distributed; and to determine that there is liquid in the pipeline to be tested when the voltage distribution information is Gaussian distributed.

4. The photoelectric sensor according to claim 1, characterized in that: The control module also includes: The bubble detection unit is used to determine that there is liquid in the pipeline to be tested and there are bubbles in the liquid when the voltage distribution information is distributed in an inverted trapezoidal shape.

5. The photoelectric sensor according to claim 4, characterized in that: The voltage distribution information at least includes first voltage distribution information corresponding to the first bubble and second voltage distribution information corresponding to the second bubble; The bubble detection unit is further used to compare the first voltage distribution information with the second voltage distribution information to determine the size of the bubble.

6. The photoelectric sensor according to claim 5, characterized in that: The size of the bubble is inversely proportional to the voltage value in the voltage distribution information.

7. The photoelectric sensor according to claim 1, characterized in that: The control module is also used to determine the change information of the voltage distribution of the transmitted light signal on the multi-pixel receiving tube over time according to the electrical signal, and determine the moving speed of the bubble according to the change information.

8. The photoelectric sensor according to claim 7, characterized in that: The control module also includes: The bubble movement speed determination unit is used to determine the voltage change rate according to the voltage distribution change information over time, and determine the bubble movement speed according to the voltage change rate.

9. The photoelectric sensor according to claim 1, characterized in that: The multi-pixel receiving tube is parallel to the axial direction of the pipeline to be tested; or The multi-pixel receiving tube is perpendicular to the axial direction of the pipeline to be tested.

10. The photoelectric 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.

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