Turbidity detection device and method

Abstract

The invention relates to a liquid analysis technology, and particularly provides a turbidity detection device and method.The turbidity detection device comprises a reaction container, a heating unit and a uniform mixing unit, the uniform mixing unit comprises a rotating part arranged on the lower side of the reaction container, and a driving unit is used for driving the rotating part to rotate; the magneton is arranged on the rotating piece, and the stirrer is arranged in the reaction container; the controller is used for adjusting the rotating speed of the rotating piece, so that the rotating speed is k * T / (Cd.mu.d3); k is a constant of 1.2-2, T is a magnetic driving torque, Cd is a magneton shape resistance coefficient, mu is the dynamic viscosity of liquid in the reaction container, and d is the diameter of the magneton. The method has the advantages of high detection precision and the like, and is applied to water quality analysis.

Description

Technical Field

[0001] The present invention relates to liquid detection technology, and in particular to a turbidity detection device and method. Background Art

[0002] There are many methods for turbidity detection in water quality instruments. For example, the methods for detecting sulfate concentration in water bodies include dry weight method, spectrophotometry, ion chromatography, etc.

[0003] Spectrophotometric detection is divided into barium sulfate turbidimetry and barium chromate spectrophotometry. The turbidimetric method uses BaSO4 particles formed by the reaction of sulfate and barium chloride to detect the absorbance of the particles and thus infer the sulfate concentration. When using the turbidimetric method for detection, it was found that after the formation of BaSO4 particles, the particles will automatically settle in the liquid, and the particles will form agglomerates in the water, forming a relatively obvious upper and lower water layer. The upper water concentration is lower and the lower water concentration is higher, causing the absorbance to shift. This phenomenon causes the absorbance to be related to factors such as mixing time, particle settling time, temperature, etc. in addition to the sulfate concentration, which brings problems to the sulfate concentration measurement. In addition to the problem of uneven particles, the problems of valve switching dead volume, bubble interference, optical path design, etc. that often appear in water quality testing are all difficult and important points in the design of sulfate detection units and need to be considered comprehensively.

[0004] In order to solve the problem of uneven particles, the following solutions are adopted: 1. Magnetic stirring method. The magnetic field below rotates to drive the magnetic particles to rotate and stir. This can effectively solve the problem of upper and lower stratification, but it will also bring centrifugal force to cause the particles to stratify inside and outside. At the same time, magnetic stirring is prone to vortexes and introduce bubbles to interfere with detection. Figure 1 shown.

[0005] If gentle stirring is used, no vortex is formed and the particle centrifugal effect is not obvious. The rotation speed of the magnetic field is closely related to the particle concentration and is difficult to control.

[0006] 2. Ultrasonic treatment method: The ultrasonic probe method is prone to generate local temperature at the probe, and the probe needs to be replaced after corrosion.

[0007] 3. Circulation pump system. A circulation pump continuously circulates the liquid to be tested throughout the entire testing system, preventing stratification of the flowing water. However, the main problem with a simple circulation pump system in water quality testing is bubbles introduced during valve switching. If bubbles circulate throughout the system, the optical path test cannot distinguish whether the bubbles are passing through, which can easily cause sudden changes in the value. Therefore, if a circulation pump system is used in water quality testing, how to deal with bubbles is also a difficult problem.

[0008] 4. Continuous perturbation (vibration table or air blowing). The continuous perturbation method uses a vibration table, which is too expensive and has poor compatibility. Experiments with the air blowing method revealed that, during small-volume testing, air bubbles can easily cause particles to settle primarily on the sides, and no bubbles can pass through during optical path testing. This means that the air blowing action cannot continue continuously, and sedimentation will occur immediately after air blowing stops. Summary of the Invention

[0009] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a turbidity detection device.

[0010] The purpose of the present invention is achieved through the following technical solutions: A turbidity detection device includes a reaction container and a heating unit; the turbidity detection device also includes a mixing unit, the mixing unit including: a rotating member and a driving unit, wherein the rotating member is disposed on the lower side of the reaction container, and the driving unit is used to drive the rotating member to rotate; a magnet and a stirrer, wherein the magnet is arranged on the rotating member, and the stirrer is arranged in the reaction container; The controller is used to adjust the rotation speed of the rotating part so that the rotation speed is k·T / (C d μd 3 ); k is a constant of 1.2-2, T is the magnetic drive torque, C d is the magnon shape drag coefficient, μ is the dynamic viscosity of the liquid in the reaction vessel, and d is the magnon diameter.

[0011] The present invention also aims to provide a turbidity detection method, which is achieved through the following technical solutions.

[0012] The turbidity detection method based on the turbidity detection device of the present invention is as follows: The sample and the reagent enter the reaction container respectively; The driving unit is used to drive the magnet on the rotating member to rotate at the lower side of the reaction container, thereby driving the stirring bar in the reaction container to rotate; The controller adjusts the rotation speed of the rotating part so that the rotation speed is k·T / (C d μd 3 ); k is a constant of 1.2-2, T is the magnetic drive torque, C d is the magnon shape drag coefficient, μ is the dynamic viscosity of the liquid in the reaction vessel, and d is the magnon diameter; The gas in the mixed liquid escapes from the liquid surface and gathers in the upper part of the reaction container.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Small sample and reagent requirements; The reaction container and the detection container are set separately. The detection container adopts a small volume and long optical path design, which reduces the consumption of reagents and samples. 2. High detection accuracy; like Figure 3 As shown, by limiting the rotation speed of the rotating part, vortexes, air and centrifugal force interference will not be introduced, and bubbles are eliminated from the mixed liquid sent to the detection container, thereby improving the detection accuracy; The irregular vortex and high-frequency shear force generated by the stirrer accelerate the mixing of pollutants in the sample and the reagents, thereby increasing the reaction speed, shortening the detection time and improving the detection accuracy. The use of a circulating pump not only enables the detection of small volumes and long optical paths in the detection container, but also helps to reduce the impact of sedimentation in the mixed liquid; 3. Low installation process requirements; The speed self-regulating process coordinated with the detection unit and the mixing unit solves the difficulty of operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are merely used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Figure 1 This is a diagram of the stirring effect in the prior art; Figure 2 is a schematic structural diagram of a turbidity detection device according to the present invention; Figure 3 1 is a diagram showing the stirring effect according to the present invention. DETAILED DESCRIPTION

[0015] Figure 2-Figure 3 The following description describes optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or substitutions derived from these embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional embodiments, but is limited only by the claims and their equivalents.

[0016] Example 1:

[0017] A turbidity detection device of this embodiment, such as Figure 1 As shown, the device includes: The reaction container 11 and the heating unit are used to heat the liquid in the reaction container 11. The upper part of the liquid surface in the reaction container 11 is empty to accommodate the gas escaping from the liquid surface.

[0018] The mixing unit includes a rotating member 33, a driving unit 31, a magnet 41, a stirrer 42 and a controller.

[0019] The rotating member 33 is disposed at the lower side of the reaction container 11 , and the driving unit 31 is used to drive the rotating member 33 to rotate.

[0020] The magnet 41 is disposed on the rotating member 33 , and the stirrer 42 is disposed in the reaction container 11 .

[0021] The controller is used to adjust the rotation speed of the rotating member 33 so that the rotation speed is k·T / (C d μd 3 ).

[0022] k is a constant of 1.2-2, T is the magnetic drive torque, C d is the shape resistance coefficient of the magneton 41, μ is the dynamic viscosity of the liquid in the reaction container 11, and d is the diameter of the magneton 41.

[0023] In order to reduce the consumption of samples and reagents, the turbidity detection device further includes: The inlet and outlet of the detection container 12 are connected to the reaction container 11 through pipelines.

[0024] The detection unit 51 is used to obtain the turbidity of the liquid in the detection container 12 .

[0025] A pump 13 is provided on the pipeline.

[0026] In order to eliminate bubbles and improve detection accuracy, the inlet of the detection container 12 is further connected to the bottom outlet of the reaction container 11 , and the bottom outlet of the detection container 12 is connected to the top inlet of the reaction container 11 .

[0027] In order to implement bottom sampling and eliminate the influence of bubbles, an inlet is provided at the bottom end of the detection container 12 and an outlet is provided at the top end.

[0028] In order to achieve sampling and detection, the turbidity detection device further includes: The switching module 22 is used to selectively connect the bottom outlet to the detection container 12 or the sample.

[0029] In order to eliminate the influence between the pipeline and the rotating member 33, the rotating member 33 is further configured as a gear with a through hole inside for allowing the pipeline to pass through, and the driving unit 31 is configured as a motor.

[0030] Based on the turbidity detection method of the turbidity detection device according to the embodiment of the present invention, the detection method is: The sample and reagent enter the reaction container 11 respectively.

[0031] The driving unit 31 is used to drive the magnet 41 on the rotating member 33 to rotate at the lower side of the reaction container 11 , thereby driving the stirring element 41 in the reaction container 11 to rotate.

[0032] The controller adjusts the rotation speed of the rotating member 33 so that the rotation speed is k·T / (C d μd 3 ).

[0033] k is a constant of 1.2-2, T is the magnetic drive torque, C d is the shape drag coefficient of the magneton 41, μ is the dynamic viscosity of the liquid in the reaction container 11, and d is the diameter of the magneton 41; The gas in the mixed liquid escapes from the liquid surface and gathers in the upper part of the reaction container 11. Figure 3 shown.

[0034] In order to reduce the consumption of samples and reagents, the mixed liquid in the reaction container 11 is further discharged into the detection container 12 , and the mixed liquid discharged from the detection container 12 is further discharged into the reaction container 11 .

[0035] The detection unit obtains the turbidity of the mixed liquid in the detection container 12 .

[0036] In order to obtain a suitable rotation speed, the photoelectric detection unit 51 further obtains the transmitted light intensity value of the detection container 12; Determine whether the adjacent transmitted light intensity value is less than the set value; If the answer is no, the rotation speed of the rotating member 33 is increased and the transmitted light intensity value is obtained again; If the result is yes, the detection unit 51 obtains the turbidity of the mixed liquid in the detection container 12 .

[0037] In order to eliminate bubbles and improve detection accuracy, the mixed liquid is further discharged from the bottom of the reaction container 11 and enters from the bottom of the detection container 12, then discharged from the top of the detection container 12 and enters from the top of the reaction container 11, forming a cycle.

[0038] Example 2:

[0039] An example of application of the turbidity detection device and method according to an embodiment of the present invention in water quality detection.

[0040] In this application example, Figure 2As shown, a first switching module 21 (using a two-position three-way solenoid valve) is provided at the top opening of the reaction container 11, so that the opening is selectively connected to the outside world (to achieve pressure relief) or a pipeline, and a second switching module 22 (using a two-position three-way solenoid valve) is provided at the bottom opening, so that the opening is selectively connected to the sample or the pipeline.

[0041] In the mixing unit, the drive unit 31 employs a motor, driving the first gear 32 and the rotating member 33 (which is a second gear meshing with the first gear 32). The rotating member 33 is located below the reaction vessel 11 and has a central through-hole to allow the second switching module 22 to pass through, preventing interference. A cylindrical magnet 41 is fixed to the upper side of the rotating member 33, and a stirrer 42 is located within the reaction vessel 11.

[0042] A pipeline connects the second switching module 22 to the bottom opening of the detection container 12, and the top opening of the detection container 12 to the first switching module 21. A pump 13 is mounted on the pipeline. The horizontal length of the detection container 12 is greater than its vertical height, resulting in a large measurement optical path. The detection unit 51 includes a light source and a detector, and uses photoelectric detection technology to determine the turbidity of the mixed liquid in the detection container 12.

[0043] For low concentration liquids, such as water, the magnetic drive torque T ranges from 10 -6 ~10 -5 N·M, drag coefficient C d For cylindrical magnetons 41 is about 10~20, T and C d The ranges of values ​​are empirical and can be set within this range. The dynamic viscosity μ of the liquid (i.e., water) in reaction vessel 11 is 0.001 Pas at room temperature, and the magnetic particle diameter d is the actual diameter of the magnetic particle 41 used. Adjustment and measurement of these parameters are conventional techniques in the field of magnetic stirring.

[0044] In this embodiment, the values ​​of each parameter are: T=5.2×10 -6 N.M.C. d =15, μ=0.001Pas, d=0.008m.

[0045] Based on the turbidity detection method of the turbidity detection device according to the embodiment of the present invention, the detection method is: The sample and reagent enter the reaction container 11 from the bottom through the second switching module 22 respectively.

[0046] The driving unit 31 drives the magnet 41 on the rotating member 33 to rotate at the lower side of the reaction container 11 , thereby driving the stirrer 41 in the reaction container 11 to rotate, and the bubbles in the mixed liquid escape from the liquid surface and enter the upper part of the reaction container 11 .

[0047] The first switching module 21 and the second switching module 22 switch, and under the transportation of the pump 13, the mixed liquid in the reaction container 11 is discharged through the second switching module 22, then enters the detection container 12 from the bottom, and finally enters the reaction container 11 through the first switching module 21.

[0048] The detection unit 51 obtains the transmitted light intensity value of the detection container 12; Determine whether the difference between adjacent transmitted light intensity fluctuations is less than the set value (in this case, the adjacent fluctuations of the light intensity conversion voltage signal do not exceed 0.2V); If the answer is no, the controller increases the rotation speed of the rotating member 33 and re-obtains the transmitted light intensity value; If the answer is yes, the speed is k·T / (C d μd 3 )=812rpm, k=1.2. Figure 3 As shown, dilution stirring does not introduce vortexes, air or centrifugal force interference.

[0049] The detection unit 51 uses photoelectric technology to obtain the turbidity of the mixed liquid in the detection container 12.

[0050] The above embodiment merely exemplifies that k is 1.2. Of course, it can also be other values ​​within the range of 1.2-2, such as 1.4, 1.5, 1.7, 2, etc., but preferably within the range of 1.2-1.5.

Claims

1. A turbidity detection device, comprising a reaction container and a heating unit; characterized in that: The turbidity detection device further includes a mixing unit, and the mixing unit includes: a rotating member and a driving unit, wherein the rotating member is disposed on the lower side of the reaction container, and the driving unit is used to drive the rotating member to rotate; a magnet and a stirrer, wherein the magnet is arranged on the rotating member, and the stirrer is arranged in the reaction container; The controller is used to adjust the rotation speed of the rotating part so that the rotation speed is k·T / (C d μd 3 ); k is a constant of 1.2-2, T is the magnetic drive torque, C d is the magnon shape drag coefficient, μ is the dynamic viscosity of the liquid in the reaction vessel, and d is the magnon diameter.

2. The turbidity detection device according to claim 1, characterized in that The turbidity detection device also includes: a detection container, wherein the inlet and outlet of the detection container are connected to the reaction container through pipelines; a detection unit, the detection unit being used to obtain the turbidity of the liquid in the detection container; A pump is provided on the pipeline.

3. The turbidity detection device according to claim 2, characterized in that The inlet of the detection container is connected to the bottom outlet of the reaction container, and the bottom outlet of the detection container is connected to the top inlet of the reaction container.

4. The turbidity detection device according to claim 3, characterized in that The turbidity detection device also includes: A switching module is used to selectively connect the bottom outlet to the detection container or the sample.

5. The turbidity detection device according to claim 2, characterized in that: An inlet is arranged at the bottom end of the detection container, and an outlet is arranged at the top end.

6. The turbidity detection device according to claim 1, characterized in that The rotating member is a gear having a through hole therein for allowing the pipe to pass through, and the driving unit is a motor.

7. A turbidity detection method based on the turbidity detection device of claim 1, wherein the detection method is: The sample and the reagent enter the reaction container respectively; The driving unit is used to drive the magnet on the rotating member to rotate at the lower side of the reaction container, thereby driving the stirring bar in the reaction container to rotate; The controller adjusts the rotation speed of the rotating part so that the rotation speed is k·T / (C d μd 3 ); k is a constant of 1.2-2, T is the magnetic drive torque, C d is the magnon shape drag coefficient, μ is the dynamic viscosity of the liquid in the reaction vessel, and d is the magnon diameter; The gas in the mixed liquid escapes from the liquid surface and gathers in the upper part of the reaction container.

8. The detection method according to claim 7, characterized in that The mixed liquid in the reaction container is discharged and enters the detection container, and the mixed liquid discharged from the detection container enters the reaction container; The detection unit obtains the turbidity of the mixed liquid in the detection container.

9. The detection method according to claim 8, characterized in that The photoelectric detection unit obtains the transmitted light intensity value of the detection container; Determine whether the adjacent transmitted light intensity value is less than the set value; If the result is negative, the rotation speed of the rotating member is increased and the transmitted light intensity value is obtained again; If the result is yes, the detection unit obtains the turbidity of the mixed liquid in the detection container.

10. The detection method according to claim 7, characterized in that: The mixed liquid is discharged from the bottom end of the reaction container and enters from the bottom end of the detection container, then discharged from the top end of the detection container and enters from the top end of the reaction container, forming a cycle.

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