Optical waveguide water level and water quality detection device

Abstract

The invention relates to an optical waveguide water level and water quality detection device. According to the device, the water level change and the water pollution condition of the water storage device are measured in a non-contact manner in an optical waveguide sensing manner, and intelligent management of water level and water quality detection is facilitated. According to the specific scheme, the side wall of a water storage bin is made of an optical material, the refractive index is higher than that of drinking water, laser is coupled into the side wall of the water storage bin and alternately reflected on the inner surface and the outer surface of the side wall, and the vertical interval of two adjacent times of reflection on the same surface is the measurement precision; when the outer side of the surface is in contact with air, light is totally reflected, when the surface is in contact with drinking water, partial reflection occurs, light beam energy in the side wall of the water storage bin is lost in a transmission mode, and the more the partial reflection times are, the higher the water level is, the larger the laser beam energy loss is; the number of times of partial reflection can be calculated by calculating the loss of laser energy, so that the water level height is calculated. When the water level is kept unchanged, the loss of laser energy can be increased along with the increase of the water pollution degree, so that the water pollution and the pollution of the bin wall of the water storage device are monitored.

Description

TECHNICAL FIELD

[0001] The present application relates to the fields of photoelectric sensing, optical waveguide technology and water level detection, in particular to an optical waveguide water level and water quality detection device. BACKGROUND

[0002] In modern society, intelligentization is an inevitable trend of device development, and the same is true for water level and water quality detection. Water level monitoring and water quality control of water storage devices such as swimming pools, water reservoirs and pet drinking water devices are gradually transitioning from traditional manual operation to intelligentization and automation. How to effectively detect changes in water level and water quality and connect with intelligent terminals is a problem that needs to be solved at present. SUMMARY

[0003] Therefore, the present application provides an optical waveguide water level and water quality detection device, which can measure the water level height and water pollution of a water storage tank in real time, and alert the user or link to an intelligent terminal to carry out water replacement or cleaning work when the water level is below a designated threshold or when the pollution reaches a certain level, thereby improving the intelligence level.

[0004] To achieve the above-mentioned purpose, the technical solutions of the embodiments of the present application are as follows:

[0005] One exemplary embodiment includes a laser, a laser collimator, a water storage tank side wall, a mirror, a reflective base, a light collector, a photodetector and a signal processing system. The laser outputs monochromatic laser light, which is collimated into parallel light by the laser collimator, coupled into the water storage tank side wall through the mirror at the upper end of the water storage tank side wall, and the inner and outer surfaces of the water storage tank are parallel, the outer surface is in contact with air, and the inner surface is in contact with air or water, forming an optical waveguide. The refractive index of the water storage tank side wall is higher than that of drinking water. The part of the water storage tank side wall in contact with air undergoes total reflection, and the part in contact with water undergoes partial reflection and partial transmission. The optical fiber transmitted in the water storage tank side wall is emitted at the bottom of the water storage tank, changes the transmission direction by the reflective base, is collected by the light collector, and is transmitted to the photodetector. The photodetector and the laser are both controlled by the signal processing system. The signal of the photodetector is received by the signal processing system, and a warning signal is sent out by the signal processing system, such as an intelligent software warning or a water dispenser buzzer warning.

[0006] When the water level in the water storage tank is below the designated threshold, all reflections of the light on the water storage tank side wall are total reflections, the light power loss caused by the transmission process is minimal, and the light power received by the photodetector is maximal. When the water level in the water storage tank is higher than the lowest reflection position of the inner surface of the tank side wall, part of the light is transmitted at the reflection position below the water level, resulting in a large loss of light power. The more reflection positions the water level spans, the more serious the loss. The water level position can be calculated by the loss, and the accuracy is the numerical distance between the adjacent two reflection positions of the inner or outer surface of the water storage tank.

[0007] In some embodiments, the reference light and signal light can be separated by means of light splitting, and the light source power calibration and the calculation of the number of total reflections can be performed by comparing the received power of the signal light with the power of the reference light.

[0008] In some embodiments, the laser can be replaced by a wide-spectrum light source, and the water level detection can be achieved in combination with the color light effect.

[0009] In some embodiments, the divergent laser can be used for transmission.

[0010] In some embodiments, one or more of the laser collimator, the mirror, the reflecting base, and the light collector can be excluded.

[0011] In some embodiments, the transmission direction of the light can be from bottom to top.

[0012] In some embodiments, the shape of the side wall of the water storage tank can be changed so that the light propagates in a specified area, and the water level in the local area can be detected.

[0013] In some embodiments, the laser and the photodetector can be placed vertically or obliquely.

[0014] In some embodiments, the photodetector can be arranged at the base position to detect the water quality and the dirt accumulation at the bottom of the water storage tank by the transmittance of the light in the water storage tank.

[0015] In some embodiments, the local area of the side wall of the water storage tank can be made of an optical material, and the other areas can be made of a non-optical material.

[0016] Advantages:

[0017] The present application uses the sensing method of optical waveguide, and uses the functional relationship between the output laser power and the water level height as the detection method of the water level height. The water storage condition of the pet water dispenser can be detected in real time, the pet owner can be guided to replace the pet drinking water, and the intelligence of the pet water dispenser can be improved. At the same time, as a non-contact sensing method, the optical waveguide can effectively avoid false alarms caused by accidental touch of surrounding objects, and the reliability can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The basic structure of the optical waveguide water level detection device of the present application is depicted.

[0019] Figure 2 The method for calibrating the light source power by using the light splitting structure of the present application is depicted.

[0020] Figure 3 The method for changing the structure of the side wall of the water storage tank to control the incident and emergent positions of the light is depicted.

[0021] Figure 4The method for detecting water pollution and reservoir pollution by transmitting light in water through the structure of the application is described. DETAILED DESCRIPTION

[0022] The application will be described in detail below with reference to the accompanying drawings Figure 1 The application is described in detail by way of example.

[0023] The light waveguide water level detection device includes a laser 1, a laser collimator 2, a reservoir side wall 3, a mirror 4, a reflective base 5, a light collector 6, a photodetector 7, and a signal processing system 14.

[0024] It should be noted that the structures and concepts in the light waveguide water level detection device are for auxiliary understanding, not the structure of the device, including drinking water 8, reservoir side wall reflection angle 9, underwater transmitted light 11, minimum side water level 12, and drinking water level 13.

[0025] The specific workflow of this embodiment is as follows:

[0026] The laser 1 emits monochromatic laser light as a signal light;

[0027] The laser collimator 2 collimates the monochromatic laser light emitted by the laser 1 into parallel light;

[0028] The mirror 4 is made by cutting the top end of the reservoir side wall 3 into an inclined plane and coating it with an optical reflective film, and couples the collimated laser light output by the laser collimator 2 to the reservoir side wall 3. The reservoir side wall reflection angle 9 is between the minimum total reflection angle between the reservoir side wall 3 and the air and the minimum total reflection angle between the reservoir side wall 3 and the drinking water.

[0029] The reservoir side wall 3, as a light waveguide, is made of optical material, and the inner and outer surfaces are parallel to each other. The refractive index of the optical plastic is higher than that of the drinking water, including but not limited to optical plastic. The refractive index of the optical material is higher than that of air and water. When the light is transmitted in the reservoir side wall 3, total reflection occurs at the air interface and partial reflection and partial transmission occur at the drinking water interface. The underwater transmitted light 11 is lost in the water, and the final reflected light is emitted at the bottom of the reservoir side wall 3. It should be noted that the underwater transmitted light 11 is not a single light, but refers to all light emitted from the reservoir side wall 3 into the drinking water 8;

[0030] The reflective base 5 is made of metal reflective material, and the area in contact with the reservoir side wall 3 is designed as an inclined plane to reflect the light emitted from the bottom of the reservoir side wall 3 to the direction of the light collector 6;

[0031] The light collector 6 collects the light in the light transmission area and couples it to the photodetector 7;

[0032] The photodetector 7 converts the signal laser into an electrical signal and transmits it to the signal processing system;

[0033] The signal processing system 14 calculates the drinking water level 13 according to the size of the light power, and initiates a warning to the pet owner when the drinking water level 13 is lower than a threshold value of interest to the pet owner. In addition, the signal processing system can control the laser 1 and the photodetector 7 to work periodically to reduce power consumption and maintain the service life of the laser 1 and the photodetector 7.

[0034] The calculation method of the height of the drinking water level 13 and the reflection angle 9 of the water storage tank side wall in this embodiment is as follows:

[0035] The number of reflections on the inner surface of the water storage tank is N (N is a positive integer), wherein the number of total reflections is N1 (N1 is a natural number), and the number of partial reflections is N2 (N2 is a natural number), then

[0036] N = N1 + N2

[0037] In this embodiment, the number of total reflections on the outer surface of the water storage tank side wall 3 is equal to the number of reflections on the inner surface.

[0038] The laser power emitted by the laser 1 is P, and the laser power received by the photodetector 7 is P a , the thickness of the water storage tank side wall 3 is d, the refractive index of the water storage tank side wall 3 is n1, the refractive index of the drinking water 8 is n2 (1 < n2 < n1), the distance between the lowest water level 12 and the bottom of the inner wall of the water storage tank is h t (h t > 0), the interval Δh of two reflections on the inner surface of the water storage tank side wall 3, the reflection angle 9 of the water storage tank side wall, the reflectivity r1 when total reflection occurs in the water storage tank side wall 3, the reflectivity r2 when partial reflection occurs (r2 < r1), the reflectivity r3 of the reflector 4, the reflectivity r4 of the reflecting base 5, the transmittance t1 of the laser collimator 2, the transmittance t2 of the incident light on the outer surface of the water storage tank side wall 3, the transmittance t3 of the bottom of the water storage tank side wall 3, and the transmittance t4 of the light collector 6. In this embodiment, all reflectivities and transmittances are positive real numbers less than 1 by default.

[0039] The calculation range of the water level height 13 is:

[0040] h ∈ [N2Δh - Δh + h t , N2Δh + h t )

[0041] Wherein the calculation of N2 is as follows:

[0042]

[0043] When the water level is lower than the lowest water level 12, i.e. N2 = 0, the photodetector receives power P all , then

[0044] P all = t1t2r3r1 2N t3r4t4P

[0045] At this time, the laser power received by the photodetector 7 is P a Rewritten as

[0046]

[0047] The number of reflections of the inner surface of the side wall 3 of the water storage tank is N2

[0048]

[0049] Wherein, r1 can be measured in advance, r2 is slightly different when the water storage tank stores different quality drinking water, a reference value can be provided in advance, or the water storage tank can be filled with water for accurate measurement, P all Can be measured without water and set in advance.

[0050] The interval Δh (also known as measurement accuracy) of twice reflection of the inner surface of the side wall 3 of the water storage tank is calculated as follows:

[0051] Δh = 2dtan(θ)

[0052] Wherein, the reflection angle 9 of the side wall of the water storage tank is determined as follows:

[0053] The refractive index of air is considered as 1, the minimum value θ min of the total reflection angle at the junction of the side wall 3 of the water storage tank and air is

[0054]

[0055] The minimum value θ max of the total reflection angle at the junction of the side wall 3 of the water storage tank and drinking water 8 is

[0056]

[0057] At this time, according to 1 < n2 < n1, θ max > θ min , so when θ ∈ [θ min , θ max ) can make the light at the junction of the side wall of the water storage tank and air total reflection, and the junction of drinking water partial reflection.

[0058] The final expression of the height of the water level 13 of the drinking water is:

[0059]

[0060] In some embodiments, when the water level does not change, Pall Detecting the pollution degree of water quality over time.

[0061] In some embodiments, the combination of the attached Figure 2 The reference light 17 and the signal light 18 can be separated by the beam splitter 19, the signal light 18 is transmitted in the water storage tank side wall 3, the reference light 17 is collected by the light collector 15 and coupled to the photodetector 16, the photodetector 16 outputs the measured laser power data to the control system 14, the control system compares the change multiple of the laser power before and after the operation of the photodetector 16, and the P all Complete the correction, weaken the influence of the measurement accuracy decline caused by the aging of the laser 1.

[0062] In some embodiments, the laser 1 can be replaced by a wide-spectrum light source, for example, an LED lamp, which can be set as a colored light, and the water level measurement can be completed by the energy loss of the wide-spectrum light in the water storage tank side wall 3, or a filtering device can be added in front of the photodetector 7 or the light collector 6 to intercept part of the wavelength of the light to complete the water level measurement.

[0063] In some embodiments, one or more of the laser collimator 2, the mirror 4, the reflective base 5 and the light collector 6 can not be included. For example, the laser collimator 2 is not included, and the laser divergence system is increased or not increased, and the divergent laser is used for transmission. For example, the light collector 6 is not included, and the direction of the light entering the photodetector 7 is limited by limiting the light aperture, and the influence of stray light is reduced. For example, the mirror 4 can not be included, and the laser 1 is placed at the top end of the water storage tank side wall 3, and the light is coupled to the water storage tank side wall 3 from top to bottom. For example, the reflective base 5 can not be included, and the photodetector is placed at the lower end of the water storage tank side wall 3 to receive the light from top to bottom. For example, one or more of the laser collimator 2, the mirror 4, the reflective base 5 and the light collector 6 can not be included, and the characteristics are combined.

[0064] In some embodiments, the transmission direction of the light can be from bottom to top, for example, the positions of the laser 1 and the photodetector 7 are exchanged, and the positions of the laser collimator 2 and the light collector 6 are exchanged.

[0065] In some embodiments, the shape of the water storage tank side wall 3 can be changed to make the light propagate in a specified area to realize the water level detection of a local area, for example, the combination of the attached Figure 3An entrance notch 20 and an exit notch 21 can be designed on the side wall 3 of the water storage tank. The entrance notch 20 couples light into the side wall 3, while the exit notch 21 separates the light from the side wall 3. The distance between the entrance notch 20 and the exit notch 21 sets the number of reflections on the inner surface of the side wall 3. The relative position of the entrance notch 20 and the exit notch 21 selects the measurement area of ​​interest. A reduced number of reflections means that the laser power can be reduced, saving energy. For example, the number of reflections on the inner surface of the side wall 3 is set to 1. This reflection position is the alarm threshold. If the drinking water level 13 is lower than this reflection position, an alarm is triggered. The entrance notch 20 and the exit notch 21 can be protrusions.

[0066] In some embodiments, water quality and dirt accumulation at the bottom of the water storage tank are detected by measuring the transmittance of light within the tank. For example, in conjunction with the attached... Figure 4 An optical window can be set up in a portion of the reflective base 5. A light collector 22 and a photodetector 23 can be placed inside the reflective base 5. At least a portion of the underwater transmitted light 11 enters the bottom 24 of the water storage tank after being transmitted in the water. The bottom 24 of the water storage tank is made of optical material or partially made of optical material. The light is transmitted in the bottom 24 of the water storage tank, then exits to the optical window area of ​​the reflective base 5, and enters the reflective base 5 again. It is then coupled to the photodetector 23 by the light collector 22. Since the transmittance of the drinking water 8 is poor after it becomes turbid, and dirt usually adheres to the top of the bottom 24 of the water storage tank, further reducing the transmittance, the pollution problem of the drinking water 8 and the bottom 24 of the water storage tank can be detected by detecting the change in the laser power received by the photodetector 23, indicating whether the water needs to be changed.

[0067] In some embodiments, a portion of the sidewall 3 of the water storage tank can be made of optical plastic, while other areas can be made of non-optical plastic, and the drinking water level 13 can be measured using the optical plastic area.

[0068] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A waveguide water level and water quality detection device, characterized in that, Includes a laser, a laser collimator, a water tank sidewall, a reflector, a reflector base, a light collector, a photodetector, and a signal processing system; The laser and the laser collimator provide collimated laser; The sidewalls of the water storage tank are made of optical material with a refractive index higher than that of drinking water. The inner and outer surfaces of the sidewall of the water storage tank are parallel to each other, with the outer surface in contact with air and the inner surface in contact with air or water, forming an optical waveguide; The top of the side wall of the water storage tank is treated as a reflector to couple light into the side wall of the water storage tank. In the side wall of the water storage tank, light undergoes total internal reflection at the surface in contact with air and partial reflection at the surface in contact with drinking water; The reflective base is made of a reflective material, such as a thin metal film coated on its surface, which deflects the light emitted from the bottom of the side wall of the water storage tank, so that the light is collected by the light collector and coupled to the photodetector. The signal processing system calculates the number of partial reflections occurring on the sidewall of the water storage tank based on the strength of the photoelectric detection signal, and calculates the drinking water level height with an accuracy of the height interval between two adjacent reflections on the same surface. The signal processing system indicates the pollution level of the water and the sidewalls of the water storage tank based on the strength of the photoelectric detection signal, assuming the water level remains constant. A strong signal indicates less pollution, while a weak signal indicates more pollution. The signal processing system compares the water level with an alarm threshold. If the water level is below the threshold, it alerts the user or connects to a smart terminal to perform operations such as adding or changing water or cleaning.

2. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... The laser can be replaced with a broadband light source, such as an LED light or a colored light array.

3. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... It may exclude one or more of the laser collimator, the reflector, the reflector base, and the light collector.

4. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... Diverging light can be used for water level detection.

5. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... The positions of light emission and light reception can be interchanged, and the direction of light transmission is from bottom to top.

6. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... The shape of the sidewall of the water storage tank can be changed to serve as an incident or exit port for light, for example, by adding notches or protrusions to allow light to propagate in a designated area.

7. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... An optical window can be set on the reflective base, and a light receiving device can be added inside the reflective base to detect the pollution status of drinking water and water storage tanks by measuring the loss of light power.

8. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... Designated areas of the water storage tank sidewall can be made of optical materials, while other areas can be made of non-optical materials to save costs.

9. The optical waveguide water level and water quality detection device according to claim 1, characterized in that... The power conversion of the laser can be detected by spectral analysis, which can mitigate the adverse effects of laser aging.

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