A new type of high temperature resistant photoelectric liquid level sensor

Abstract

The utility model discloses a novel high temperature resistant photoelectric liquid level sensor which is suitable for high temperature environment detection and has a stable installation structure. The adopted technical scheme includes: a shell and a PCB board arranged in the shell, an infrared emitting diode and an infrared receiving diode are arranged on the PCB board, the shell is composed of an integrally formed front shell and a rear shell, a prism is integrally formed on the top of the front shell, two independently spaced light guide columns are installed in the front shell through a shading bushing, the rear ends of the shading bushing and the light guide column extend into the rear shell, the PCB board is installed at the rear end of the shading bushing, and the light emitted by the infrared emitting diode is reflected by the prism and conducted by the light guide column and then received by the infrared receiving diode. The advantages are as follows: through the shading bushing and the light guide column arranged in the shell, the emitting diode and the receiving diode can be installed away from the heat source, and at the same time, through the heat isolation of the shading bushing and the light guide column, the normal working temperature is less than 50 degrees.

Description

Technical Field

[0001] The utility model belongs to the field of sensors, and in particular relates to a temperature photoelectric liquid level sensor. Background Art

[0002] The photoelectric liquid level sensor contains a near-infrared emitting diode and an infrared receiving diode. The light emitted by the light-emitting diode is directed to the prism on the top of the sensor. (Water state) When the liquid submerges the prism of the photoelectric liquid level sensor, the light is refracted into the liquid, so that the receiver cannot receive or can only receive a small amount of light, which is detected as a water state. (Anhydrous state) When there is no liquid, the light emitted by the light-emitting diode is directly reflected from the prism back to the infrared receiving diode. By sensing this change in working condition, the photoelectric liquid level sensor can drive the internal electrical switch, thereby starting an external alarm or control circuit. The disadvantages of traditional photoelectric liquid level sensors are: 1. When used for high-temperature (such as greater than 100 degrees) liquid environment detection, since the distance between the infrared emitting diode, the infrared receiving diode and the prism is very close, generally less than 1mm, the high temperature of the prism in contact with the liquid will be directly transmitted to the infrared emitting and receiving diodes. At this time, the temperature of the infrared emitting and receiving diodes will exceed 80 degrees, resulting in light attenuation or damage to the infrared light-emitting diode and the infrared receiving diode, and then resulting in a decrease in the detection sensitivity of the sensor or failure; 2. There is no internal positioning structure, which can easily cause the PCB board and the diode to be easily displaced during installation and use, which can easily lead to the inability to receive light, resulting in product failure. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a novel high temperature resistant photoelectric liquid level sensor which is suitable for high temperature environment detection and has a stable installation structure.

[0004] In order to solve the above problems, the technical solution adopted by the utility model includes: a shell and a PCB board arranged in the shell, the PCB board is provided with an infrared emitting diode and an infrared receiving diode, the shell is composed of an integrally formed front shell and a rear shell, and a prism is integrally formed on the top of the front shell, and is characterized in that: two independently spaced light guide columns are installed in the front shell through a shading bushing, the shading bushing and the rear end of the light guide column both extend into the rear shell, the PCB board is installed at the rear end of the shading bushing, and the light emitted by the infrared emitting diode is reflected by the prism and conducted by the light guide column and then received by the infrared receiving diode.

[0005] The novel high temperature resistant photoelectric liquid level sensor is characterized in that: a diode mounting seat placed in the rear shell body is provided at the rear end of the light shielding bushing, two diode mounting cavities are provided on the diode mounting seat, and the infrared emitting diode and the infrared receiving diode are installed in the diode mounting cavity by interference fit.

[0006] The novel high temperature resistant photoelectric liquid level sensor is characterized in that: the front shell is a cylindrical structure and is provided with an external thread, the rear shell is a hexagonal column structure and has an outer diameter larger than the front shell, a positioning step is formed between the front shell and the rear shell, a first positioning ring is provided at the rear end of the light-shielding bushing and is positioned to cooperate with the positioning step, guide ribs are provided on both sides of the first positioning ring, a guide groove is provided in the rear shell and is guided to cooperate with the guide rib, and the guide groove is formed by two convex ribs arranged at intervals.

[0007] The novel high temperature resistant photoelectric liquid level sensor is characterized in that a second positioning ring is provided behind the light shielding bushing corresponding to the first positioning ring thereof, and a positioning notch is provided on the second positioning ring to cooperate with the convex rib for positioning.

[0008] The novel high temperature resistant photoelectric liquid level sensor is characterized in that the rear shell is filled with thermal conductive silica gel and a heat dissipation port is provided at the rear end.

[0009] The novel high temperature resistant photoelectric liquid level sensor is characterized in that: the PCB board is connected with a wire extending out of the rear housing.

[0010] The novel high temperature resistant photoelectric liquid level sensor is characterized in that a cylindrical end face is integrally formed at the front end of the rear shell, and a sealing ring is provided on the cylindrical end face.

[0011] The novel high temperature resistant photoelectric liquid level sensor is characterized in that the prism is conical and has a top angle of 45 degrees.

[0012] The advantages of the new high-temperature resistant photoelectric liquid level sensor of the utility model are as follows: 1. Through the shading bushing and the light guide column arranged in the shell, the emitting diode and the receiving diode can be installed away from the heat source. At the same time, the heat is isolated by the shading bushing and the light guide column, so that the normal working temperature is less than 50 degrees; 2. Through multiple internal positioning structures (positioning between the diode mounting seat and the diode, positioning between the positioning step and the first positioning ring, positioning between the guide rib and the guide groove, positioning between the second positioning ring and the convex rib), the light guide column and the PCB board can be accurately positioned and stably installed.

[0013] The utility model is further described below in conjunction with the accompanying drawings of the specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1This is a schematic diagram of the structure of the photoelectric liquid level sensor of the utility model;

[0015] Figure 2 This is an exploded view of the photoelectric liquid level sensor of the utility model;

[0016] Figure 3 It is a cross-sectional view of the photoelectric liquid level sensor of the utility model;

[0017] Figure 4 It is a structural schematic diagram of the utility model shading bushing;

[0018] Figure 5 It is a schematic diagram of the internal structure of the housing of the utility model;

[0019] Figure 6 This is the circuit schematic diagram of the utility model photoelectric liquid level sensor;

[0020] Figure 7 This is a working principle diagram of the photoelectric liquid level sensor of the utility model. DETAILED DESCRIPTION

[0021] Reference Figure 1-7 As shown, the novel high temperature resistant photoelectric liquid level sensor of the utility model comprises a housing 1 and a PCB board 2 arranged in the housing 1. The housing 1 is made of high temperature resistant transparent plastic. The PCB board 2 is provided with an infrared emitting diode 3 and an infrared receiving diode 4, and the housing 1 is composed of an integrally formed front housing 5 and a rear housing 6, and a prism 7 is integrally formed on the top of the front housing 5. Two independently spaced light guides 9 are installed in the front housing 5 through a light shielding bushing 8, and the front end of the light shielding bushing 8 is attached to the prism 7, and the front end of the light guide 9 is attached to or close to the prism 7. The light shielding bushing 8 is ideally made of high temperature resistant black plastic. The rear ends of the light shielding bushing 8 and the light guide 9 extend into the rear housing 6, and the PCB board 2 is installed at the rear end of the light shielding bushing 8 and is located in the rear housing 6. The light emitted by the infrared emitting diode 3 is received by the infrared receiving diode 4 after being reflected by the prism 7 and conducted by the light guide 9.

[0022] Preferably, the rear end of the shading bushing 8 is provided with a diode mounting seat 10 placed in the rear housing 6, and the diode mounting seat 10 is provided with two diode mounting cavities 11, and the infrared emitting diode 3 and the infrared receiving diode 4 are installed in the diode mounting cavity 11 in an interference fit manner, and the end of the connecting light guide column 9 is aligned with the diode mounting cavity 11. In this way, the infrared emitting diode 3, the infrared receiving diode 4 and the shading bushing 8 can be stably installed, so that they can be accurately connected to the light guide column 9.

[0023] Preferably, the front housing 5 is a cylindrical structure and is provided with an external thread 12, the rear housing 6 is a hexagonal column structure and has an outer diameter greater than the front housing 5, a positioning step 13 is formed between the front housing 5 and the rear housing 6, a first positioning ring 14 is provided at the rear end of the light-shielding bushing 8 for positioning and matching with the positioning step 13, guide ribs 15 are provided on both sides of the first positioning ring 14, and a guide groove 16 for guiding and matching with the guide rib 15 is provided in the rear housing 6, and the guide groove 16 is formed by two convex ribs 17 arranged at intervals. Through the above structure, while facilitating the connection between the housing 1 and the corresponding object, the precise docking and stable connection between the light-shielding bushing 8 and the housing 1 can also be achieved.

[0024] Preferably, the shading bushing 8 is provided with a second positioning ring 18 behind the first positioning ring 14 thereof, and the second positioning ring 18 is provided with a positioning notch 19 which is positioned and matched with the convex rib 17, so as to further improve the accuracy and stability of the installation of the shading bushing 8.

[0025] Preferably, the rear housing 6 is filled with thermally conductive silica gel, and a heat dissipation port 23 is provided at the rear end, so as to have better thermal conductivity and waterproof effect.

[0026] Preferably, the PCB board 2 is connected with a wire 20 extending out of the rear housing 6 to facilitate wiring.

[0027] Preferably, the front end of the rear housing 6 is integrally formed with a cylindrical end face 21, and a sealing ring 22 is provided on the cylindrical end face 21. The cylindrical end face 21 cooperates with the sealing ring 22, so that the housing installation is more stable and the sealing performance is better.

[0028] Preferably, the prism 7 is conical, and the vertex angle is 45 degrees, so that the prism 7 can achieve reflection at all angles.

[0029] The above does not limit the present invention in any form. Although the present invention has been disclosed as a preferred implementation case as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to the equivalent implementation cases of equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A novel high temperature resistant photoelectric liquid level sensor, comprising a housing (1) and a PCB board (2) arranged in the housing (1), the PCB board (2) being provided with an infrared emitting diode (3) and an infrared receiving diode (4), the housing (1) being composed of an integrally formed front housing (5) and a rear housing (6), the top of the front housing (5) being integrally formed with a prism (7), characterized in that: Two independently spaced light guide columns (9) are installed in the front housing (5) via a light shielding bushing (8); the rear ends of the light shielding bushing (8) and the light guide column (9) extend into the rear housing (6); the PCB board (2) is installed at the rear end of the light shielding bushing (8); and the light emitted by the infrared emitting diode (3) is received by the infrared receiving diode (4) after being reflected by the prism (7) and conducted by the light guide column (9).

2. According to the novel high temperature resistant photoelectric liquid level sensor of claim 1, it is characterized in that: A diode mounting seat (10) is provided at the rear end of the light-shielding bushing (8) and is placed in the rear housing (6). Two diode mounting cavities (11) are provided on the diode mounting seat (10). The infrared emitting diode (3) and the infrared receiving diode (4) are installed in the diode mounting cavities (11) in an interference fit manner.

3. According to the novel high temperature resistant photoelectric liquid level sensor of claim 2, it is characterized in that: The front housing (5) is a cylindrical structure and is provided with an external thread (12); the rear housing (6) is a hexagonal column structure and has an outer diameter greater than that of the front housing (5); a positioning step (13) is formed between the front housing (5) and the rear housing (6); a first positioning ring (14) is provided at the rear end of the light-shielding bushing (8) and is positioned to cooperate with the positioning step (13); guide ribs (15) are provided on both sides of the first positioning ring (14); a guide groove (16) is provided in the rear housing (6) and is guided to cooperate with the guide rib (15); the guide groove (16) is formed by two convex ribs (17) arranged at intervals.

4. The novel high temperature resistant photoelectric liquid level sensor according to claim 3 is characterized in that: The light-shielding bushing (8) is provided with a second positioning ring (18) at the rear of the first positioning ring (14), and the second positioning ring (18) is provided with a positioning notch (19) that cooperates with the convex rib (17) in positioning.

5. According to claim 1, the novel high temperature resistant photoelectric liquid level sensor is characterized in that: The rear housing (6) is filled with heat-conducting silica gel, and a heat dissipation port (23) is provided at the rear end.

6. The novel high temperature resistant photoelectric liquid level sensor according to claim 1 is characterized in that: The PCB board (2) is connected to a wire (20) extending out of the rear housing (6).

7. The novel high temperature resistant photoelectric liquid level sensor according to claim 3 is characterized in that: A cylindrical end surface (21) is integrally formed at the front end of the rear housing (6), and a sealing ring (22) is provided on the cylindrical end surface (21).

8. The novel high temperature resistant photoelectric liquid level sensor according to claim 1 is characterized in that: The prism (7) is conical in shape, and has a vertex angle of 45 degrees.

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