Non-contact photoelectric liquid level sensor

Abstract

The utility model discloses a non-contact photoelectric liquid level sensor, which relates to the technical field of photoelectric liquid level sensors and comprises a protective shell, a sensor body is mounted at the bottom end of the inner side of the protective shell, a shell cover is clamped at the top end of the protective shell and covers the top end of the protective shell, and an incident light indicating lamp is mounted at the top end of the shell cover. By adopting the structure, the ventilation opening can facilitate ventilation and heat dissipation of the sensor body, the first dustproof plate and the second dustproof plate can prevent a large amount of dust from entering the sensor body, meanwhile, circulating air can enter the protective shell in a bending manner, and the filter plate can perform good secondary filtration on convection ventilation, so that good dustproof and heat dissipation effects can be achieved; when the position where the sensor body is used needs a good sealing effect, a user can directly pull down the sealing plate according to the sliding principle, the sealing plate can completely cover the position of the ventilation opening, and therefore the good sealing protection effect can be achieved.

Description

Technical Field

[0001] This utility model belongs to the field of photoelectric liquid level sensor technology, and specifically relates to a non-contact photoelectric liquid level sensor. Background Technology

[0002] Non-contact photoelectric liquid level sensors are an innovative liquid level monitoring technology. They work on the principle of optical sensing and do not require direct contact with the liquid being measured. The sensor determines the liquid level by emitting and receiving light and detecting the refraction or absorption of the light. This type of sensor has the advantages of high precision, high reliability, and no moving mechanical parts. It is suitable for liquid level monitoring in various small household appliances and equipment. It is easy to install and maintain, and is especially suitable for occasions where water tanks need to be moved frequently or equipment needs to be kept clean.

[0003] Chinese patent with announcement number "CN215217751U" discloses a non-contact photoelectric liquid level sensor. The non-contact photoelectric liquid level sensor includes: a housing assembly, a PCB board, a pair of tubes assembly, and a wire sealing gasket. The PCB board is disposed inside the housing assembly. The pair of tubes assembly includes: a transmitting pair of tubes and a receiving pair of tubes. The transmitting pair of tubes is soldered on the PCB and is located on one side of the transmitting pair of tubes.

[0004] However, the above structure still has some shortcomings. Because the sensor contains many small electrical components, and the sensor's mounting point is generally inside the machine, and the sensor's housing structure generally does not have a corresponding heat dissipation structure, its heat dissipation method is also to open heat dissipation vents. This heat dissipation method can allow dust or contaminants to enter the sensor, thereby damaging the sensor. In addition, depending on the different instruments the sensor is used on, it also needs to have a corresponding waterproof sealing structure. Therefore, sensors with heat dissipation structures and sensors with waterproof sealing structures must be used separately, which increases costs and reduces the scope of application of the sensor itself. Utility Model Content

[0005] In view of the problems mentioned in the background art, the purpose of this utility model is to provide a non-contact photoelectric liquid level sensor to solve the problems mentioned in the background art.

[0006] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0007] A non-contact photoelectric liquid level sensor includes a protective housing, a sensor body installed at the bottom inner side of the protective housing, a cover snapped onto the top of the protective housing, the cover covering the top of the protective housing, an incident light indicator installed on the top of the cover, a wire provided on the top of the cover, a switch provided on the top of the cover, a limiting groove is formed on one side of the protective housing, a vent is formed on one side of the limiting groove, the vent communicates with the inside of the protective housing, a filter plate is slidably connected to the inner wall of the vent, the filter plate covers the inner side of the vent, a limiting frame is inserted into one side of the limiting groove, a first dustproof plate and a second dustproof plate are fixedly connected to the inner side of the limiting frame, the position of the second dustproof plate corresponds to the position of the filter plate, a sealing plate is slidably connected to the inner wall of the protective housing, a second protrusion is fixedly connected to the other side of the sealing plate, and the sealing plate covers the other side of the vent.

[0008] As a preferred technical solution, a first sliding groove matching the filter plate is provided on the inner wall of the vent, and the filter plate is slidably connected to the inner wall of the vent through the first sliding groove. A second sliding groove matching the sealing plate is provided on the inner wall of the protective shell, and the sealing plate is slidably connected to the inner wall of the protective shell through the second sliding groove.

[0009] As a preferred technical solution, a first groove is provided at the bottom inner side of the vent, and a magnet is fixedly connected to the bottom inner side of the first groove. The magnet covers the inner side of the first groove, and the bottom end of the filter plate is attached to the top end of the magnet. The bottom end of the filter plate is made of magnetic material.

[0010] As a preferred technical solution, a second groove is provided on the inner wall of the protective shell, and a second sealing ring is fixedly connected to the inner side of the second groove. The second sealing ring covers the inner side of the second groove, and the other side of the second sealing ring is in contact with one side of the sealing plate.

[0011] As a preferred technical solution, a slot is provided on one side of the limiting groove, and a plug that matches the slot is fixedly connected to the other side of the limiting frame. The plug is fixedly connected to the four sides near the corner of the other side of the limiting frame, and the plug is inserted into the inside of the slot. The limiting frame is inserted into one side of the limiting groove through the slot and the plug.

[0012] As a preferred technical solution, the top of the protective shell is provided with a positioning groove, and the bottom of the shell cover is fixedly connected with a positioning block that matches the positioning groove. The positioning block is fixedly connected to the four sides near the corner of the bottom of the shell cover, and the positioning block is engaged with the inside of the positioning groove.

[0013] As a preferred technical solution, a first slot is provided at the top of the cover, the first slot extends into the interior of the protective shell, a second slot is provided on the inner wall of the first slot, a circular groove is provided at the bottom inner side of the first slot, a first locking block is engaged with the inner side of the first slot, and a second locking block that matches the second slot is fixedly connected to the outer side of the first locking block, the second locking block is engaged with the inner side of the circular groove.

[0014] As a preferred technical solution, a retaining spring that matches the second retaining block is installed at the bottom inner side of the circular groove. The top of the retaining spring is engaged with the bottom of the second retaining block, and the second retaining block is engaged with the inner side of the circular groove by the retaining spring. A sealing block is fixedly connected to the top of the first retaining block, and the sealing block covers the top of the first retaining groove. A first protrusion is fixedly connected to the top of the sealing block, and the shape of the corner of the first protrusion is arc-shaped.

[0015] As a preferred technical solution, a first sealing ring is fixedly connected to the top of the protective shell. The first sealing ring is located on the inner side of the first locking block, and a sealing groove matching the first sealing ring is opened at the bottom of the shell cover. The first sealing ring covers the inner side of the sealing groove.

[0016] As a preferred technical solution, a rectangular opening is provided on the front side of the protective shell, the rectangular opening is connected to the inside of the protective shell, and a transparent glass is fixedly connected to the inside of the rectangular opening, the transparent glass covering the inside of the rectangular opening.

[0017] In summary, the present invention has the following main advantages:

[0018] Firstly, during use, the ventilation openings facilitate ventilation and heat dissipation for the sensor body. The first and second dustproof plates effectively block dust and pollutants in the air to prevent a large amount of dust from entering. At the same time, they allow the airflow to enter the protective shell in a curved manner, so that the filter plate and the airflow can have closer contact. This allows the filter plate to perform good secondary filtration of the airflow, achieving a good dustproof and heat dissipation effect. When the sensor body is used at a point that requires a good sealing effect, the user can directly pull down the sealing plate by sliding. The sealing plate can completely cover the ventilation opening point, thereby achieving a good sealing and protection effect and effectively improving the application range of the sensor body.

[0019] Secondly, due to the presence of the insert block, the insertion of the insert block can effectively limit the position of the limiting frame to prevent it from shifting. It also makes it easier for users to disassemble it individually later for cleaning or maintenance of its internal structure. The magnetic attraction of the insert block can effectively limit the position of the filter plate to prevent it from shifting. When it needs to be disassembled individually for maintenance or cleaning later, it can also be pulled out directly through the first slide groove. Due to the presence of the second sealing ring, it can fit together with the sealing plate, which can effectively improve the sealing effect of the sealing plate on the ventilation opening. At the same time, the rubber-type second sealing ring has good anti-slip ability to prevent the sealing plate from shifting after closing.

[0020] Third, the presence of the first locking block facilitates the insertion of the second locking block into the circular groove. By adjusting the second locking block to a position that does not correspond to the second locking groove, the cover can be effectively engaged. The locking spring further enhances the stability of the second locking block's engagement, preventing displacement. The insertion of the positioning block, while limiting the cover's position, also effectively improves the accuracy of the first locking block's insertion. When it needs to be disassembled later, the second locking block is rotated to the position corresponding to the second locking groove, the first locking block is pulled out directly, and finally the positioning block is pulled out of the positioning groove. This facilitates the disassembly and assembly of the cover and also makes it easier for users to inspect or maintain the inner structure of the protective shell. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the shell cover structure of this utility model;

[0023] Figure 3 This is a schematic diagram of the inner structure of the protective shell of this utility model;

[0024] Figure 4 This is a utility model Figure 3 A magnified structural diagram of part A;

[0025] Figure 5 This is a schematic diagram of the inner structure of the ventilation opening of this utility model;

[0026] Figure 6 This is a utility model Figure 5 A schematic diagram of the enlarged structure of part B;

[0027] Figure 7 This is a schematic diagram of the inner structure of the limiting groove of this utility model;

[0028] Figure 8 This is a schematic diagram of the limiting frame structure of this utility model.

[0029] Reference numerals: 1. Protective housing; 2. Sensor body; 3. Positioning groove; 4. First sealing ring; 5. Housing cover; 6. Positioning block; 7. Sealing groove; 8. First slot; 9. Second slot; 10. Circular groove; 11. Snap ring; 12. First locking block; 13. Second locking block; 14. Sealing block; 15. First protrusion; 16. Wire; 17. Switch; 18. Light inlet indicator; 19. Rectangular opening; 20. Transparent glass; 21. Limiting groove; 22. Ventilation opening; 23. Filter plate; 24. First sliding groove; 25. First recess; 26. Magnet; 27. Second recess; 28. Second sealing ring; 29. ​​Second sliding groove; 30. Sealing plate; 31. Second protrusion; 32. Slot; 33. Limiting frame; 34. First dustproof plate; 35. Second dustproof plate; 36. Insert block. Detailed Implementation

[0030] Example

[0031] refer to Figures 1 to 8This embodiment describes a non-contact photoelectric liquid level sensor, comprising a protective housing 1, a sensor body 2 mounted on the inner bottom of the protective housing 1, a cover 5 snapped onto the top of the protective housing 1, the cover 5 covering the top of the protective housing 1, an incident light indicator 18 mounted on the top of the cover 5, a wire 16 provided on the top of the cover 5, a switch 17 provided on the top of the cover 5, a limiting groove 21 formed on one side of the protective housing 1, a ventilation opening 22 formed on one side of the limiting groove 21, the ventilation opening 22 communicating with the inner side of the protective housing 1, a filter plate 23 slidably connected to the inner wall of the ventilation opening 22, the filter plate 23 covering the inner side of the ventilation opening 22, and a sensor body 23 inserted into one side of the limiting groove 21. The limiting frame 33 has a first dustproof plate 34 and a second dustproof plate 35 fixedly connected to its inner side. The position of the second dustproof plate 35 corresponds to the position of the filter plate 23. A sealing plate 30 is slidably connected to the inner wall of the protective shell 1. A second protrusion 31 is fixedly connected to the other side of the sealing plate 30. The sealing plate 30 covers the other side of the vent 22. The non-contact photoelectric liquid level sensor is a liquid level detection device based on the principle of optical sensing. Its basic structure includes a transmitter, a receiver, and a light-transmitting cone. The transmitter emits infrared light, which is refracted by the light cone. When there is no water, the light returns completely to the receiver. When there is water, the light is refracted into the water, and the amount of light received by the receiver is reduced. The sensor body 2 determines the liquid level based on changes in light received by the receiver. When the liquid level rises, more light is refracted by the liquid, reducing the amount of light received by the receiver. The sensor then outputs a corresponding signal, achieving non-contact liquid level monitoring. This sensor body 2 does not require direct contact with the liquid, offering advantages such as high precision, easy installation, and low maintenance costs. During use, the ventilation opening 22 facilitates ventilation and heat dissipation for the sensor body 2. Its first dustproof plate 34 and second dustproof plate 35 effectively block dust and pollutants from the air, preventing a large amount of dust from entering. Simultaneously, it allows the airflow to enter the protective housing 1 in a curved manner, ensuring closer contact between the filter plate 23 and the airflow. This allows the filter plate 23 to perform good secondary filtration of the airflow, achieving excellent dust prevention and heat dissipation. When a good sealing effect is required at the point where the sensor body 2 is used, the user can directly slide down the sealing plate 30, which completely covers the ventilation opening 22, thus providing excellent sealing and protection.

[0032] refer to Figures 1 to 6The inner wall of the vent 22 is provided with a first sliding groove 24 that matches the filter plate 23. The filter plate 23 is slidably connected to the inner wall of the vent 22 through the first sliding groove 24. The inner wall of the protective shell 1 is provided with a second sliding groove 29 that matches the sealing plate 30. The sealing plate 30 is slidably connected to the inner wall of the protective shell 1 through the second sliding groove 29. The opening of the first sliding groove 24 can effectively pull the sliding point of the filter plate 23, and also facilitates the user to disassemble and install the filter plate 23 later. The opening of the second sliding groove 29 can effectively pull the sliding direction of the sealing plate 30, and also facilitates the user to disassemble the sealing plate 30 according to the usage requirements of the sensor body 2.

[0033] refer to Figures 1 to 6 The bottom inner side of the vent 22 is provided with a first groove 25. A magnet 26 is fixedly connected to the bottom inner side of the first groove 25. The magnet 26 covers the inner side of the first groove 25. The bottom end of the filter plate 23 is attached to the top end of the magnet 26. The bottom end of the filter plate 23 is made of magnetic material. Due to the presence of the magnet 26, the attraction of the magnet 26 can effectively limit the position of the filter plate 23 to prevent it from shifting. When it needs to be disassembled separately for maintenance or cleaning, it can also be directly pulled out through the first slide 24.

[0034] refer to Figures 1 to 6 A second groove 27 is provided on the inner wall of the protective shell 1. A second sealing ring 28 is fixedly connected to the inner side of the second groove 27. The second sealing ring 28 covers the inner side of the second groove 27. The other side of the second sealing ring 28 is in contact with one side of the sealing plate 30. Due to the presence of the second sealing ring 28, it can fit together with the sealing plate 30, which can effectively improve the sealing effect of the sealing plate 30 on the vent 22. At the same time, the second sealing ring 28 is a rubber product. The rubber second sealing ring 28 has good anti-slip ability to prevent the sealing plate 30 from shifting after closing, thus also playing a good limiting effect.

[0035] refer to Figure 7 and Figure 8 A slot 32 is provided on one side of the limiting groove 21, and a plug 36 matching the slot 32 is fixedly connected to the other side of the limiting frame 33. The plug 36 is fixedly connected to the four sides near the corner of the other side of the limiting frame 33. The plug 36 is inserted into the inside of the slot 32. The limiting frame 33 is inserted into one side of the limiting groove 21 through the slot 32 and the plug 36. Due to the presence of the plug 36, the insertion of the plug 36 can effectively limit the position of the limiting frame 33 to prevent it from shifting. It also makes it easier for users to disassemble it individually later for cleaning or maintenance of its internal structure.

[0036] refer to Figures 1 to 4The protective outer shell 1 has a positioning groove 3 at its top. A positioning block 6 matching the positioning groove 3 is fixedly connected to the bottom of the shell cover 5. The positioning block 6 is fixedly connected to the four sides near the corners of the bottom of the shell cover 5 and engages with the inside of the positioning groove 3. The top of the shell cover 5 has a first slot 8 extending into the interior of the protective outer shell 1. A second slot 9 is formed on the inner wall of the first slot 8. A circular groove 10 is formed at the bottom of the inner side of the first slot 8. A first locking block 12 is attached to the side, and a second locking block 13, matching the second locking groove 9, is fixedly connected to the outer side of the first locking block 12. The second locking block 13 is engaged with the inner side of the circular groove 10. A retaining spring 11, matching the second locking block 13, is installed at the bottom inner side of the circular groove 10. The top of the retaining spring 11 is engaged with the bottom of the second locking block 13. The second locking block 13 is engaged with the inner side of the circular groove 10 via the retaining spring 11. A sealing block 14 is fixedly connected to the top of the first locking block 12. 4. The top of the first slot 8 is covered by the sealing block 14, and the top of the sealing block 14 is fixedly connected to the first protrusion 15. The first protrusion 15 has an arc-shaped corner. Due to the presence of the first locking block 12, it is easy for the second locking block 13 to be inserted into the circular groove 10. The second locking block 13 is adjusted to a position that is not corresponding to the second slot 9, so that the cover 5 can be effectively locked. The locking of the spring 11 can further improve the stability of the locking of the second locking block 13 to avoid displacement. The insertion of the positioning block 6 not only limits the position of the cover 5, but also effectively improves the accuracy of the insertion of the first locking block 12. When it needs to be disassembled later, the second locking block 13 is rotated to the position corresponding to the second slot 9, and then the first locking block 12 is pulled out directly. Finally, the positioning block 6 is pulled out of the positioning groove 3. This not only facilitates the disassembly and assembly of the cover 5 later, but also makes it easier for users to inspect or maintain the inner structure of the protective shell 1 later.

[0037] refer to Figures 1 to 4 The top of the protective shell 1 is fixedly connected with a first sealing ring 4. The first sealing ring 4 is located on the inner side close to the first locking block 12. The bottom end of the shell cover 5 is provided with a sealing groove 7 that matches the first sealing ring 4. The first sealing ring 4 covers the inner side of the sealing groove 7. Due to the presence of the first sealing ring 4, the first sealing ring 4 can effectively seal the connection point between the protective shell 1 and the shell cover 5, thereby effectively improving the sealing effect of the overall protective shell 1 and improving the overall sealing and dustproof performance of the shell.

[0038] refer to Figure 1A rectangular opening 19 is provided on the front side of the protective housing 1. The rectangular opening 19 communicates with the inside of the protective housing 1. A transparent glass 20 is fixedly connected to the inside of the rectangular opening 19, and the transparent glass 20 covers the inside of the rectangular opening 19. Because of the opening 19, the user can directly view the inside of the protective housing 1 through the transparent glass 20 without opening the housing cover 5, which is conducive to the user to observe the operation status of the sensor body 2 at all times, thereby improving the safety protection of the sensor body 2.

[0039] Operating principle and advantages: During use, the opening of the vent 22 facilitates ventilation and heat dissipation for the sensor body 2. The first dustproof plate 34 and the second dustproof plate 35 effectively block dust and pollutants in the air, preventing a large amount of dust from entering. Simultaneously, it allows the airflow to enter the protective housing 1 in a curved manner, ensuring closer contact between the filter plate 23 and the airflow. This allows the filter plate 23 to perform good secondary filtration of the airflow, achieving excellent dust prevention and heat dissipation. When a good sealing effect is required at the point where the sensor body 2 is used, the user can directly slide down the sealing plate 30. The sealing plate 30 completely covers the vent 22, thus achieving a good sealing and protective effect. Due to the first sliding groove 24... The opening of the first sliding groove 24 allows for effective traction of the sliding points of the filter plate 23, facilitating its disassembly and installation by the user. The second sliding groove 29 also effectively guides the sliding direction of the sealing plate 30, allowing for easy removal of the sealing plate 30 according to the user's needs. The presence of the magnet 26 effectively limits the position of the filter plate 23 to prevent displacement. For later maintenance or cleaning, it can be directly pulled out via the first sliding groove 24. The second sealing ring 28 fits snugly against the sealing plate 30, effectively improving the sealing effect of the sealing plate 30 on the vent 22. 8 is a rubber product. The rubber-type second sealing ring 28 has good anti-slip ability to prevent the sealing plate 30 from shifting after closing, thus also providing a good limiting effect. Due to the presence of the insert block 36, the insertion of the insert block 36 can effectively limit the position of the limiting frame 33 to prevent its displacement. It also facilitates the user to disassemble it individually for cleaning or maintenance of its internal structure. Due to the presence of the first locking block 12, it is easy for the second locking block 13 to be inserted into the circular groove 10. Adjusting the second locking block 13 to a position that is not directly corresponding to the second locking groove 9 can effectively engage the cover 5. The engagement of the retaining spring 11 can further improve the stability of the engagement of the second locking block 13 to prevent its displacement. The insertion of the positioning block 6... While limiting the cover at point 5, it also effectively improves the accuracy of inserting the first locking block at point 12. When it needs to be disassembled later, the second locking block 13 is rotated to the corresponding point of the second locking groove 9, and then the first locking block 12 is pulled out directly. Finally, the positioning block 6 is pulled out of the positioning groove 3. This not only facilitates the disassembly and assembly of the cover 5 later, but also makes it easier for users to inspect or maintain the inner structure of the protective shell 1. Due to the presence of the first sealing ring 4, the connection point between the protective shell 1 and the cover 5 can be effectively sealed, thereby effectively improving the overall sealing effect of the protective shell 1 and improving the overall sealing and dustproof performance of the shell. Due to the opening of the rectangular opening 19, the user can remove the cover 5 without opening it.The transparent glass 20 allows direct viewing of the inside of the protective housing 1, facilitating constant observation of the sensor body 2's operational status and enhancing its safety.

Claims

1. A non-contact photoelectric liquid level sensor, comprising a protective housing, characterized in that: A sensor body is installed on the inner bottom of the protective housing. A cover is snapped onto the top of the protective housing, covering the top of the protective housing. An indicator light is installed on the top of the cover. A wire is provided on the top of the cover. A switch is provided on the top of the cover. A limiting groove is formed on one side of the protective housing. A ventilation opening is formed on one side of the limiting groove. The ventilation opening communicates with the inner side of the protective housing. A filter plate is slidably connected to the inner wall of the ventilation opening. The filter plate covers the inner side of the ventilation opening. A limiting frame is inserted into one side of the limiting groove. A first dustproof plate and a second dustproof plate are fixedly connected to the inner side of the limiting frame. The position of the second dustproof plate corresponds to the position of the filter plate. A sealing plate is slidably connected to the inner wall of the protective housing. A second protrusion is fixedly connected to the other side of the sealing plate. The sealing plate covers the other side of the ventilation opening.

2. The non-contact photoelectric liquid level sensor according to claim 1, characterized in that: The inner wall of the vent is provided with a first sliding groove that matches the filter plate. The filter plate is slidably connected to the inner wall of the vent through the first sliding groove. The inner wall of the protective shell is provided with a second sliding groove that matches the sealing plate. The sealing plate is slidably connected to the inner wall of the protective shell through the second sliding groove.

3. The non-contact photoelectric liquid level sensor according to claim 1, characterized in that: The vent has a first groove at its inner bottom end, and a magnet is fixedly connected to the inner bottom end of the first groove. The magnet covers the inner side of the first groove. The bottom end of the filter plate is in contact with the top end of the magnet. The bottom end of the filter plate is made of magnetic material.

4. The non-contact photoelectric liquid level sensor according to claim 1, characterized in that: The inner wall of the protective shell is provided with a second groove, and a second sealing ring is fixedly connected to the inner side of the second groove. The second sealing ring covers the inner side of the second groove, and the other side of the second sealing ring is in contact with one side of the sealing plate.

5. A non-contact photoelectric liquid level sensor according to claim 1, characterized in that: A slot is provided on one side of the limiting groove, and a plug that matches the slot is fixedly connected to the other side of the limiting frame. The plug is fixedly connected to the four sides near the corner of the other side of the limiting frame. The plug is inserted into the inside of the slot, and the limiting frame is inserted into one side of the limiting groove through the slot and the plug.

6. A non-contact photoelectric liquid level sensor according to claim 1, characterized in that: The top of the protective shell is provided with a positioning groove, and the bottom of the shell cover is fixedly connected with a positioning block that matches the positioning groove. The positioning block is fixedly connected to the four sides near the corner of the bottom of the shell cover, and the positioning block is engaged with the inside of the positioning groove.

7. A non-contact photoelectric liquid level sensor according to claim 1, characterized in that: The top of the cover is provided with a first slot, which extends into the interior of the protective shell. A second slot is provided on the inner wall of the first slot. A circular groove is provided at the bottom inner side of the first slot. A first locking block is engaged with the inner side of the first slot. A second locking block that matches the second slot is fixedly connected to the outer side of the first locking block. The second locking block is engaged with the inner side of the circular groove.

8. A non-contact photoelectric liquid level sensor according to claim 7, characterized in that: A retaining spring that matches the second retaining block is installed at the bottom inner side of the circular groove. The top of the retaining spring is engaged with the bottom of the second retaining block. The second retaining block is engaged with the inner side of the circular groove by the retaining spring. A sealing block is fixedly connected to the top of the first retaining block. The sealing block covers the top of the first retaining groove. A first protrusion is fixedly connected to the top of the sealing block. The shape of the corner of the first protrusion is arc-shaped.

9. A non-contact photoelectric liquid level sensor according to claim 7, characterized in that: The top of the protective shell is fixedly connected to a first sealing ring, which is located on the inner side close to the first locking block. The bottom of the shell cover is provided with a sealing groove that matches the first sealing ring, and the first sealing ring covers the inner side of the sealing groove.

10. A non-contact photoelectric liquid level sensor according to claim 1, characterized in that: The protective shell has a rectangular opening on its front side, which communicates with the inside of the protective shell. A transparent glass is fixedly connected to the inside of the rectangular opening, and the transparent glass covers the inside of the rectangular opening.

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