CN209961674U

CN209961674U - Turbidity detection device based on single light source dual detectors

Info

Publication number: CN209961674U
Application number: CN201920457902.6U
Authority: CN
Inventors: 张明志; 赵文龙; 马静波; 葛蜀伟; 邱杰; 娄嘉骏; 陈海华
Original assignee: Nanchang Hangkong University; Ningbo Water Meter Co Ltd
Current assignee: Nanchang Hangkong University; Ningbo Water Meter Group Co Ltd
Priority date: 2019-04-04
Filing date: 2019-04-04
Publication date: 2020-01-17
Anticipated expiration: 2029-04-04

Abstract

The utility model discloses a turbidity detection device based on single light source double detector, it includes the light source, is suitable for transparent measuring tank and two photoelectric detector that hold turbid liquid that awaits measuring, and wherein the light source is suitable for to transparent measuring tank transmission measuring beam, and measuring beam takes place the scattering respectively and forms two way scattered light in incident light path and transparent measuring tank, and two photoelectric detector set up respectively in the light path of two way scattered light. The utility model discloses can eliminate factor influences such as background interference, light source ageing degree difference to a certain extent, obtain comparatively accurate turbidity value, can simplify as far as possible on the design again, practice thrift economic cost.

Description

Turbidity detection device based on single light source dual detectors

Technical Field

The present invention relates to a turbidity detecting device, and more particularly to a turbidity detecting device based on a single light source and dual detectors.

Background

Turbidity is the degree of obstruction of light by a solution, and includes scattering of light by suspended matter and absorption of light by solute molecules. Turbidity is a basic index in water quality detection and has a very important position. The scattering phenomenon can take place when the light shines water sample solution, and the light intensity of scattered light is directly proportional with the size of solution turbidity basically, through the scattered light intensity of survey through the water sample scattering, can calculate the turbidity of water sample indirectly.

Current turbidimeters commonly use 90 ° light scattering for turbidity measurements. Common designs are single light source single detector or dual light source dual detector. The single light source and single detector is simple in design, but interference of background factors is difficult to eliminate, and the double-light source and double-detector can give more accurate detection results, but the design is more complex and the cost is higher.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a turbidity detection device based on two detectors of single light source can eliminate interference factors such as background interference, the ageing difference of light source to a certain extent, simple structure, and the cost is lower to an economic effectual scheme has realized the high accuracy measurement of quality of water turbidity.

In order to achieve the above object, the present invention provides a turbidity detecting device based on a single light source dual detector, which includes:

the measuring device comprises a light source, a transparent measuring groove suitable for containing turbid liquid to be measured and two photoelectric detectors, wherein the light source is suitable for emitting measuring light beams to the transparent measuring groove, the measuring light beams are scattered in an incident light path and the transparent measuring groove respectively to form two paths of scattered light, and the two photoelectric detectors are arranged in the light paths of the two paths of scattered light respectively.

The turbid liquid to be detected and the incident light path in the detection environment both have suspended particles, so the measuring beam can form interference scattered light (namely background noise) in the incident light path, and simultaneously form scattered light to be detected (namely signal quantity) in the turbid liquid to be detected, the two photoelectric detectors can detect the interference scattered light and the scattered light to be detected respectively, the signal quantity of the interference scattered light is subtracted from the signal quantity of the scattered light to be detected during signal processing (namely background interference is eliminated), and then scale conversion is carried out, so that a more accurate turbidity value can be obtained.

Preferably, the two photodetectors are each disposed on an extension of the scattered light at 90 degrees to the measuring beam, where the scattered light received is least sensitive to variations in the particle size of the suspended particles and is least affected by stray light (light from non-scattering paths).

According to the preferred embodiment of the present invention, the turbidity detecting apparatus based on single light source dual detector further comprises two signal conditioning circuits, an analog-to-digital conversion circuit and a microprocessor, wherein the two signal conditioning circuits are respectively connected to the two photodetectors, and the analog-to-digital conversion circuit is respectively connected to the two signal conditioning circuits and the microprocessor;

the two photoelectric detectors convert respective detection quantities into voltage quantities and respectively transmit the voltage quantities to the two signal conditioning circuits, the signal conditioning circuits amplify and filter the obtained voltage quantities, the analog-to-digital conversion circuits are suitable for converting the two voltage quantities into corresponding digital quantities and transmitting the digital quantities to the microprocessor, the microprocessor subtracts the two obtained digital quantities (namely, the signal quantities subtract background noise) and performs filtering processing, and then scale conversion is performed to obtain a turbidity value without background interference.

Preferably, the turbidity detecting device based on the single-light-source dual detector further comprises a display, the display is connected to the microprocessor, and the display is suitable for displaying the turbidity value processed by the microprocessor.

Preferably, the single light source dual detector-based turbidity detecting device further comprises a memory connected to the microprocessor, the memory being adapted to store data.

Compared with the prior art, the beneficial effects of the utility model reside in that: the two photoelectric detectors are both positioned on the extension line of scattered light which is perpendicular to the measuring beam by 90 degrees, and the two photoelectric detectors receive the scattered light at different angles with the single light source single detector or other double detectors, so that the influences of factors such as background interference, light source aging degree difference and the like can be eliminated to a certain extent, a more accurate turbidity value can be obtained, the design scheme can be simplified as much as possible, and the economic cost can be saved.

The above and other objects, features and advantages of the present invention will be further apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a schematic structural diagram of a turbidity detecting apparatus based on a single light source dual detector according to a preferred embodiment of the present invention;

fig. 2 is a hardware framework diagram according to a preferred embodiment of the present invention;

in the figure: a light source 10; a transparent measuring groove 20;

photodetectors

31, 32;

signal conditioning circuits

41, 42; an analog-to-digital conversion circuit 43; a microprocessor 44; a display 45; a reservoir 46; a power supply 47.

Detailed Description

The following description will be further described with reference to the accompanying drawings and specific embodiments, and it should be noted that any combination of the following described embodiments or technical features can be used to form a new embodiment without conflict.

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents and other technical solutions without departing from the spirit and scope of the invention.

It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in a generic and descriptive sense only and not for purposes of limitation, as the terms are used in the description to indicate that the referenced device or element must have the specified orientation, be constructed and operated in the specified orientation, and not for the purpose of limitation.

It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.

Referring to fig. 1 and 2 of the drawings, a turbidity detecting apparatus based on a single light source dual detector according to a preferred embodiment of the present invention will be explained in the following description, as shown in fig. 1, which includes a single light source 10, a transparent measuring cell 20 adapted to contain a turbid liquid to be measured, and two

photodetectors

31, 32, wherein the light source 10 is adapted to emit a measuring beam to the transparent measuring cell 20, the measuring beam is scattered in an incident light path and the transparent measuring cell 20 to form two scattered lights, respectively, the photodetector 31 is disposed in a path of the scattered light emitted from the incident light path, and the photodetector 32 is disposed in a path of the scattered light emitted from the transparent measuring cell 20.

The photo detector 31 and the photo detector 32 are adapted to convert the received scattered light into a voltage quantity for facilitating subsequent turbidity calculations. The photo-detector 31 and the photo-detector 32 may be a photo-electric conversion element commonly used in the art, and may be, but not limited to, a laser diode, a silicon photo-cell, etc.

Suspension particles exist in the turbid liquid to be detected and the incident light path in the detection environment, so the measuring beam can form interference scattering light (namely background noise) in the incident light path, and simultaneously form scattering light to be detected (namely signal quantity) in the turbid liquid to be detected, the interference scattering light can be detected by the photoelectric detector 31, the scattering light to be detected can be detected by the photoelectric detector 32, the signal quantity of the scattering light to be detected is subtracted by the signal quantity of the scattering light to be detected (namely background interference is eliminated), and then the calibration conversion is carried out, so that a more accurate turbidity value can be obtained.

Preferably, the photodetector 31 and the photodetector 32 are respectively arranged on an extension of the scattered light at 90 degrees to the measuring beam, where the scattered light received is least sensitive to the variation of the particle size of the suspended particles and is least affected by stray light (light of non-scattering path).

Further, as shown in fig. 2, the turbidity detecting apparatus based on single light source dual detector further includes

signal conditioning circuits

41 and 42, an analog-to-digital conversion circuit 43, a microprocessor 44, and a power supply 47, wherein the signal conditioning circuit 41 is connected to the photodetector 31, the signal conditioning circuit 42 is connected to the photodetector 32, and the analog-to-digital conversion circuit 43 is respectively connected to the two

signal conditioning circuits

41 and 42 and the microprocessor 44. The power supply 47 supplies power to the various components.

The photodetector 31 is adapted to convert the interference scattered light (i.e. background noise) in the detection environment into a voltage quantity and send the voltage quantity to the signal conditioning circuit 41, and the photodetector 32 is adapted to convert the scattered light to be detected (including background noise) formed by the turbid liquid to be detected into a voltage quantity and send the voltage quantity to the signal conditioning circuit 42. The signal conditioning circuit 41 and the signal conditioning circuit 42 amplify and filter the obtained voltage amount, and then send the amplified voltage amount to the analog-to-digital conversion circuit 43.

The analog-to-digital conversion circuit 43 is adapted to convert the two paths of voltage values into corresponding digital values and transmit the digital values to the microprocessor 44, and the microprocessor 44 subtracts the two paths of digital values (i.e. subtracts background noise from a signal quantity) and performs filtering processing, and then performs scale transformation to obtain a turbidity value without background interference.

The specific process of the microprocessor 44 for signal processing is as follows:

let D be the digital quantity of the detection quantity (background noise) of the photodetector 31 after ADC conversion₁Let D be the digital quantity of the detected quantity (background noise + turbidity signal quantity) of the photodetector 32 after ADC conversion₂In order to eliminate noise interference, the signal quantity y is taken as D₂-D₁Then, the semaphore y is equal to D₂-D₁By means of a weighted mean digital filter, the difference equation is:

wherein, s (k) is the output of the filter at the kth time; y (k) is the signal quantity at the kth sampling time, C (1), … C (N) is a weighting coefficient, and the following formula is satisfied:

a smoother semaphore S can be obtained.

And carrying out scale conversion on the relatively stable semaphore S according to the following formula:

wherein A is_m,A₀Is a known haze value of two standard solutions, S_m,S₀Is the corresponding smoother semaphore. Therefore, only a relatively level semaphore S will be measured for unknown turbidity_xSubstituting into the scale conversion formula to obtain the corresponding turbidity value A_x。

Further, the turbidity detecting device based on the single light source dual detector further comprises a display 45, the display 45 is connected to the microprocessor 44, and the display 45 is suitable for displaying the turbidity value processed by the microprocessor 44. Preferably, the display 45 is an LCD liquid crystal display.

The single light source dual detector based turbidity detecting device further comprises a memory 46, said memory 46 being connected to said microprocessor 44, said memory 46 being adapted to store data. Preferably, the memory 46 is a powered erasable programmable read-only memory (EEPROM) that does not lose data when power is removed. In addition, the microprocessor 44 can also transmit data to an upper computer through a serial port, so that the data can be analyzed conveniently at the later stage.

To sum up, the utility model discloses in, two photoelectric detector all are in on being the extension line of 90 degrees vertically scattered light with measuring beam, have respectively with single light source single detector or other two detectors in the scattered light of other angle receipt, can eliminate factor influences such as background interference, light source ageing degree difference to a certain extent, obtain comparatively accurate turbidity value, again can simplify as far as possible on the design, practice thrift economic cost.

It will be understood by those skilled in the art that the embodiments of the present invention as described above and shown in the drawings are given by way of example only and are not limiting of the present invention. The objects of the present invention have been fully and effectively accomplished. The functional and structural principles of the present invention have been shown and described in the embodiments without departing from the principles, embodiments of the present invention may have any deformation or modification.

Claims

1. Turbidity detection device based on single light source dual detector, its characterized in that includes:

2. Single light source dual detector based turbidity detecting device according to claim 1, wherein said two photo detectors are arranged on respective extensions of the scattered light at 90 degrees to said measuring beam.

3. The single light source dual detector-based turbidity detecting device according to claim 1 or 2, further comprising two signal conditioning circuits, an analog-to-digital conversion circuit, and a microprocessor, wherein said two signal conditioning circuits are connected to said two photodetectors, respectively, and said analog-to-digital conversion circuit is connected to said two signal conditioning circuits and said microprocessor, respectively.

4. The single light source dual detector-based turbidity detecting device according to claim 3, further comprising a display connected to said microprocessor, said display being adapted to display the turbidity values processed by said microprocessor.

5. A single light source dual detector-based turbidity detecting device according to claim 3, further comprising a memory, said memory being connected to said microprocessor, said memory being adapted to store data.