Particle size measuring device based on combination of dynamic light scattering method and sedimentation method and measuring method thereof

Abstract

The invention discloses a particle size measuring device based on combination of a dynamic light scattering method and a sedimentation method and a measuring method thereof. The particle size measuring device comprises a laser, a light intensity adjusting unit, a sample pool, a thermostatic bath, a PD detector, an optical fiber head, an APD detector, a data acquisition unit, a PC and a control unit. The laser emits incident laser, the incident laser passes through the light intensity adjusting unit, penetrates through the sample cell and a sample and then enters the PD detector, and a transmission light signal is collected through the data acquisition unit and transmitted to software for calculating the particle size and concentration of settled large particles; scattered light is received by an optical fiber head with a fixed angle of 90 degrees or 160-175 degrees and is converted into a digital signal by an APD detector, and the digital signal enters a data acquisition unit and is transmitted to software for calculating the particle size of particles in a non-settling nanometer range. According to the technical scheme provided by the invention, the particle size distribution information of the wide-distribution particle dispersion system in a nano-micron range can be measured in a testing process.

Description

Technical Field

[0001] The present invention relates to the field of particle size measurement, and in particular to a particle size measurement device and a measurement method based on the combination of dynamic light scattering method and sedimentation method. Background Art

[0002] The measurement technology of particle size has been widely applied in the fields of materials, chemistry and chemical engineering, food and agriculture, semiconductors, biopharmaceuticals, energy and environmental protection, etc., and plays an important role in different aspects such as the improvement of material properties and quality, the adjustment and optimization of processes, drug design, and environmental protection monitoring.

[0003] Existing particle size measurement methods each have their own advantages and limitations. The principle of the sedimentation method is based on Stokes' law, and it calculates by measuring the sedimentation velocity of particles in a liquid, which is suitable for the measurement of larger particles (micrometer level). The dynamic light scattering method calculates by measuring the scattered light fluctuations caused by the Brownian motion of particles in a liquid. It is suitable for small particle sizes, has high measurement accuracy, and fast speed.

[0004] Dynamic light scattering requires the sample to be uniform without sedimentation, and the sedimentation method cannot detect the nanoscale particle components suspended in the liquid. Therefore, it is impossible to measure the particle size distribution of samples with a particle size range covering the nano - micrometer range using only the sedimentation method or the dynamic light scattering method alone. The present invention realizes the measurement of the particle size distribution information in the nano - micrometer range of a wide - distribution particle dispersion system in one test process, where the effective detection range of the sedimentation method is 1μm - 50μm, and the effective detection range of the dynamic light scattering method is 1nm - 1μm for particles. Summary of the Invention

[0005] Aiming at the problems existing in the existing measurement methods, the present invention provides a particle size measurement device and a measurement method based on the combination of dynamic light scattering method and sedimentation method for detecting particle size. This device has the advantages of simple operation, high - efficiency and high - precision temperature control ability, small required sample volume, wide measurement range, and high overall measurement accuracy.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A particle size measurement device based on the combination of dynamic light scattering method and sedimentation method, comprising a laser, an optical intensity adjustment unit, a sample cell, a constant temperature bath, a PD detector, an optical fiber head, an APD detector, a data acquisition unit, a PC, and a control unit;

[0008] The laser emits laser light, which irradiates on the sample in the sample cell;

[0009] The sample cell contains a suspension liquid of the sample to be measured, which is a suspension of large particles with sedimentation characteristics and small particles with non - sedimentation characteristics, and the refractive index and absorption rate of the large particles and small particles are the same;

[0010] The light intensity adjustment unit includes a set of attenuation sheets mounted on a rotating wheel driven by a motor for adjusting the intensity of incident light;

[0011] The sample cell is a container for holding the sample to be measured. The internal cross-section of the sample cell is a square with a size of 10mm×10mm, the optical path length L is 10mm, the volume of the sample cell is ≥4ml, and it is designed with four-sided light transmission. The material is quartz or K9 glass;

[0012] The thermostatic bath reaches the set temperature value by receiving commands from the control unit, with an accuracy of ±0.1°C and a range of -15°C to 120°C;

[0013] The PD detector is placed at the 0° angle direction of the laser incident direction. The incident light enters the PD detector after passing through the sample cell. The PD detector is used to detect the transmitted light energy;

[0014] The fiber optic head is placed at a fixed angle in the laser incident direction. The available placement angles include: the 90° angle direction of the laser incident direction, or the 160° - 175° angle direction opposite to the laser incident direction. The scattered light enters the APD detector through the optical fiber. The APD detector is used to detect the scattered light energy;

[0015] The data acquisition unit is used to receive the signals from the PD detector and the APD detector, and transmit the signals to the PC for calculation;

[0016] The control unit is used to receive instructions from the PC side, output control signals to control the temperature of the thermostatic bath for temperature control of the test sample, and output control signals to control the position of the light intensity adjustment unit to adjust the light intensity of the incident light;

[0017] The present invention also provides a method for measuring the particle size based on the combination of dynamic light scattering method and sedimentation method, including the following measurement steps:

[0018] 1) Input the parameters required for calculation in the software: the dynamic viscosity η of the sample, the total height h of the sample, the particle density ρ p , the medium density ρ f , the refractive index n of the particle p , the absorption rate A of the particle p , the refractive index n of the medium f etc. for sedimentation particle size test, dynamic light scattering test and Mie theory calculation, and start the test;

[0019] 2) Inject the blank sample into the sample cell. The blank sample is a sample dispersion medium liquid without particles. The height of the sample liquid surface is higher than the position of the incident light detection point. Then place the sample cell in the thermostatic bath for constant temperature operation to make the blank sample reach the set temperature;

[0020] 3) Control the light intensity adjustment unit to adjust the intensity of the incident laser so that the intensity of the incident laser decays to within the linear response range of the PD detector. If there are multiple attenuation sheets corresponding to the linear range of the PD detector, use the attenuation sheet with the smallest attenuation of the incident laser intensity within the linear response range of the PD detector for testing;

[0021] 4) The PD detector collects the transmitted light intensity I0 of the blank sample;

[0022] 5) Take out the blank sample from the thermostat;

[0023] 6) Inject the sample of the mixed suspension to be tested into the sample cell, the height of the sample liquid surface is higher than the position of the incident light detection point, and then put the sample cell into the thermostat for constant temperature operation;

[0024] 7) After the constant temperature operation ends, start the sedimentation particle size test, and collect the signal of the transmitted light changing with time caused by the sedimentation of large particles in the mixed suspension sample; the PD detector transmits the signal of the transmitted light intensity changing with time collected to the PC software through the data acquisition unit, draws the relationship curve of the transmitted light intensity changing with time, and thus obtains the particle size volume distribution curve of the sedimented large particles, and further calculates D 大 [3,2];

[0025] The typical characteristics of the curve of the transmitted light intensity changing with time are: the transmitted light intensity fluctuates within a small range from the start of the test to a certain moment t0, and this time period is defined as the initial test platform. The light intensity of this platform is averaged to obtain the initial transmitted light intensity I1; starting from t0, the transmitted light intensity increases with the increase of the test time, and reaches a certain moment t n After that, the transmitted light intensity begins to fluctuate within a small range, and the transmitted light intensity basically no longer changes. Define the time from t n to the end of the test as the stable test platform. The light intensity of this platform is averaged to obtain the stable transmitted light intensity I2;

[0026] When the transmitted light signal reaches the stable test platform, the sedimentation test is completed. At this time, all the large particles in the sample have sedimented to the bottom of the sample cell, and the non-sedimenting small particles that are still suspended in the sample;

[0027] 8) Start the dynamic light scattering test. The APD detector starts to collect the dynamic light scattering test signal, and control the light intensity adjustment unit to adjust the light intensity of the incident light so that the scattered light signal is within the linear response range of the APD detector; the APD detector transmits the signal of the scattered light intensity changing with time collected to the PC software through the data acquisition unit, obtains the correlation curve through relevant calculations, and obtains the light intensity distribution curve of the non-sedimenting small particles through multi-exponential fitting, and further obtains the particle size volume distribution curve, and calculates D 小 [3,2];

[0028] 9) Through

[0029]

[0030] φ can be derived 小 , where R is half of the optical path, and Φ 小 is the total volume fraction of non-settling small particles, and Q e小 is the extinction coefficient of non-settling small particles calculated using Mie theory;

[0031] Through

[0032]

[0033] Then φ can be derived 大 , Φ 大 is the total volume fraction of settling large particles, and Q e大 is the extinction coefficient of settling large particles calculated using Mie theory;

[0034] The sum of all peak areas of the particle size volume distribution calculated by the sedimentation method is obtained as S 大 , and the sum of all peak areas of the particle size volume distribution calculated by the dynamic light scattering method is obtained as S 小 , with S 大 : S 小 = φ 小 : φ 大 The proportional relationship between the particle size distribution curves of settling large particles and non-settling small particles is obtained and integrated into a single particle size volume distribution curve;

[0035] Among them, step 8) further includes the following calculation steps:

[0036] The dynamic light scattering method uses autocorrelation technology, and the light intensity distribution of particle size can be obtained through multi-exponential fitting. The fitting formula is as follows:

[0037]

[0038] n is the number of particle size gradings.

[0039] Given n p and A p , in combination with Mie theory, the volume distribution can be derived from the light intensity distribution to obtain D 小 [3,2].

[0040] The present invention can measure the particle size distribution information in the range of nanometers to micrometers of a wide-distribution particle dispersion system in one test process, where the effective detection range of the sedimentation method is 1 μm to 50 μm, and the effective detection range of dynamic light scattering is particles of 1 nm to 1 μm. Description of the Drawings

[0041] Figure 1 Schematic diagram of the electrical principle of the device of the present invention;

[0042] Figure 2 Schematic diagram of the structure of the device of the present invention;

[0043] Figure 3 Schematic diagram of the detection optical path of the sample cell of the present invention;

[0044] Figure 4 Schematic diagram for the derivation of the sample volume distribution curve obtained during the test.

[0045] Among them, 1 is a laser, 2 is an attenuation filter group, 3 is a motor, 4 is incident light, 5 is a sample cell, 6 is a thermostat, 7 is transmitted light, 8 is a PD detector, 9 is scattered light, 10 is an optical fiber head, 11 is an APD detector, 12 is a data acquisition unit, 13 is a PC, and 14 is a control unit. Specific implementation mode

[0046] The following further elaborates on the present invention in conjunction with the attached Figures 1-4 description of the specification.

[0047] Example 1

[0048] A particle size measurement device based on the combination of dynamic light scattering method and sedimentation method, comprising a laser 1, a light intensity adjustment unit, a sample cell 5, a thermostat 6, a PD detector 8, an optical fiber head 10, an APD detector 11, a data acquisition unit 12, a PC 13, and a control unit 14;

[0049] The laser 1 emits laser light and irradiates the sample in the sample cell 5;

[0050] The sample cell 5 contains a suspension liquid of large particles with sedimentation characteristics and small particles without sedimentation characteristics as the sample to be measured;

[0051] The light intensity adjustment unit includes a group of attenuation filters 2 installed on a rotating wheel driven by a motor 3 for adjusting the intensity of incident light;

[0052] The sample cell 5 is a container for holding the sample to be measured. The internal cross-section of the sample cell is a square of 10 mm × 10 mm, the optical path L is 10 mm, the volume of the sample cell is ≥ 4 ml, and it is designed with four-sided light transmission, and the material is quartz or K9 glass;

[0053] The thermostat 6 reaches the set temperature value of 25 °C with an accuracy of ±0.1 °C by receiving the command of the control unit 14;

[0054] The PD detector 8 is placed at a 0° angle in the direction of laser incidence. The incident light 4 enters the PD detector 8 after passing through the sample cell 5, and the PD detector 8 is used to detect the energy of the transmitted light 7;

[0055] The optical fiber head 10 is placed at 90° in the direction of the incident light 4, and the scattered light 9 enters the APD detector 11 through the optical fiber 10. The APD detector 11 is used to detect the energy of the scattered light 9;

[0056] The data acquisition unit 12 is used to receive the signals from the PD detector 8 and the APD detector 11, and transmit the signals to the PC 13 for calculation;

[0057] The control unit 14 is used to receive the instructions from the PC 13, output control signals to control the temperature of the thermostat 6 to control the temperature of the test sample, and output control signals to control the position of the light intensity adjustment unit to adjust the light intensity of the incident light 4;

[0058] The measurement includes the following steps:

[0059] 1) Input the parameters required for calculation in the software: the dynamic viscosity η of the sample, the total height h of the sample, the particle density ρ p , the medium density ρ f , the refractive index n of the particles p , the absorption rate A of the particles p , the refractive index n of the medium f etc. for sedimentation particle size test, dynamic light scattering test and Mie theory calculation, and start the test;

[0060] 2) Inject the blank sample into the sample cell 5. The blank sample is a sample dispersion medium liquid without particles. The height of the sample liquid surface is higher than the position of the detection point of the incident light 4. Then place the sample cell 5 in the thermostat 6 for constant temperature operation to make the blank sample reach the set temperature;

[0061] 3) Control the light intensity adjustment unit to adjust the intensity of the incident laser 4 so that the intensity of the incident laser 4 decays within the linear response range of the PD detector 8. If there are multiple attenuation sheets corresponding to the linear range of the PD detector 8, use the attenuation sheet with the smallest attenuation of the incident laser 4 intensity within the linear response range of the PD detector 8 for testing;

[0062] 4) The PD detector 8 collects the transmitted light intensity I0 of the blank sample;

[0063] 5) Take out the blank sample from the thermostat 6;

[0064] 6) Inject the sample of the mixed suspension to be tested into the sample cell 5. The height of the sample liquid surface is higher than the position of the detection point of the incident light 4. Then place the sample cell 5 in the thermostat 6 for constant temperature operation;

[0065] 7) After the constant temperature operation ends, the sedimentation particle size test begins, and the signal of the transmitted light 7 caused by the sedimentation of large particles in the mixed suspension sample is collected over time; the PD detector 8 transmits the signal of the change in the transmitted light intensity over time collected to the PC13 software through the data acquisition unit 12, plots the relationship curve of the transmitted light intensity over time, and thereby obtains the particle size volume distribution curve of the sedimented large particles, and further calculates D 大 [3,2];

[0066] The typical characteristics of the curve of the transmitted light intensity changing with time are as follows: the transmitted light intensity fluctuates within a small range from the start of the test to a certain moment t0, and this time period is defined as the initial test platform. The light intensity of this platform is averaged to obtain the initial transmitted light intensity I1; starting from t0, the transmitted light intensity increases with the increase of the test time. When it reaches a certain moment t n After that, the transmitted light intensity begins to fluctuate within a small range and the transmitted light intensity basically no longer changes. It is defined that from t n To the end of the test is the stable test platform. The light intensity of this platform is averaged to obtain the stable transmitted light intensity I2;

[0067] When the transmitted light signal reaches the stable test platform, the sedimentation test is completed. At this time, all the large particles in the sample have sedimented to the bottom of the sample cell, and the non-sedimenting small particles that remain suspended in the sample are left;

[0068] 8) Start the dynamic light scattering test. The APD detector 11 starts to collect the dynamic light scattering test signal, and controls the light intensity adjustment unit to adjust the light intensity of the incident light 4 so that the scattered light 9 signal is within the linear response range of the APD detector 11; the APD detector 11 transmits the signal of the change in the scattered light intensity over time collected to the PC13 software through the data acquisition unit 12, obtains the correlation curve through relevant calculations, and obtains the light intensity distribution curve of the non-sedimenting small particles through multi-exponential fitting, and further obtains the particle size volume distribution curve, and calculates D 小 [3,2];

[0069] 9) Through

[0070]

[0071] It can be deduced that φ 小 , where R is half of the optical path, Φ 小 is the total volume fraction of non-sedimenting small particles, and Q e小 is the extinction coefficient of non-sedimenting small particles calculated using the Mie theory;

[0072] Through

[0073]

[0074] Then it can be deduced that φ 大 , Φ大 is the total volume fraction of sedimented large particles, Q e大 is the extinction coefficient of sedimented large particles calculated using the Mie theory;

[0075] Sum all the peak areas of the particle size volume distribution calculated by the sedimentation method to obtain S 大 , and sum all the peak areas of the particle size volume distribution calculated by the dynamic light scattering method to obtain S 小 , with S 大 : S 小 = φ 小 : φ 大 Obtain the proportional relationship between the particle size distribution curves of sedimented large particles and non-sedimented small particles, and integrate them into one particle size volume distribution curve;

[0076] Step 8) also includes the following calculation steps:

[0077] The dynamic light scattering method uses the autocorrelation technique, and the light intensity distribution of the particle size can be obtained through the multi-exponential fitting method. The fitting formula is as follows:

[0078]

[0079] n is the number of particle size classifications.

[0080] Given n p and A p , in combination with the Mie theory, the volume distribution can be deduced from the light intensity distribution to obtain D 小 [3,2].

[0081] Example 2

[0082] A particle size measuring device based on the combination of the dynamic light scattering method and the sedimentation method, comprising a laser 1, a light intensity adjusting unit, a sample cell 5, a constant temperature bath 6, a PD detector 8, an optical fiber head 10, an APD detector 11, a data acquisition unit 12, a PC 13, and a control unit 14;

[0083] The laser 1 emits laser light and irradiates the sample in the sample cell 5;

[0084] The sample cell 5 contains a suspension liquid of the sample to be measured, which is a mixture of large particles with sedimentation characteristics and small particles with non-sedimentation characteristics;

[0085] The light intensity adjusting unit includes a set of attenuation sheets 2 installed on a rotating wheel driven by a motor 3 for adjusting the intensity of incident light;

[0086] The sample cell 5 is a container for holding the sample to be measured. The internal cross-section of the sample cell is a square with a side length of 10 mm × 10 mm, the optical path L is 10 mm, the volume of the sample cell is ≥ 4 ml, and it has a four-sided light-transmitting design. The material is quartz or K9 glass;

[0087] The constant temperature bath 6 reaches the set temperature value of 50 °C with an accuracy of ±0.1 °C by receiving the command from the control unit 14;

[0088] The PD detector 8 is placed at the 0° angle direction of the laser incident direction. The incident light 4 enters the PD detector 8 after passing through the sample cell 5. The PD detector 8 is used to detect the energy of the transmitted light 7;

[0089] The fiber optic head 10 is placed at 173° in the direction of the incident light 4. The scattered light 9 enters the APD detector 11 through the optical fiber 10. The APD detector 11 is used to detect the energy of the scattered light 9;

[0090] The data acquisition unit 12 is used to receive the signals from the PD detector 8 and the APD detector 11, and transmit the signals to the PC 13 for calculation;

[0091] The control unit 14 is used to receive the instructions from the PC side 13, output control signals to control the temperature of the constant temperature bath 6 for temperature control of the test sample, and output control signals to control the position of the light intensity adjustment unit to adjust the light intensity of the incident light 4;

[0092] The measurement includes the following steps:

[0093] 1) Input the parameters required for calculation in the software: the dynamic viscosity η of the sample, the total height h of the sample, the particle density ρ p , the medium density ρ f , the refractive index n of the particle p , the absorption rate A of the particle p , the refractive index n of the medium f etc. for sedimentation particle size test, dynamic light scattering test and Mie theory calculation, and start the test;

[0094] 2) Inject the blank sample into the sample cell 5. The blank sample is a sample dispersion medium liquid without particles. The liquid level height of the sample is higher than the detection point position of the incident light 4. Then place the sample cell 5 into the constant temperature bath 6 for constant temperature operation to make the blank sample reach the set temperature;

[0095] 3) Control the light intensity adjustment unit to adjust the intensity of the incident laser 4 so that the intensity of the incident laser 4 decays within the linear response range of the PD detector 8. If there are multiple attenuation sheets corresponding to the linear range of the PD detector 8, use the attenuation sheet with the smallest attenuation of the incident laser 4 intensity within the linear response range of the PD detector 8 for testing;

[0096] 4) The PD detector 8 collects the transmitted light intensity I0 of the blank sample;

[0097] 5) Take out the blank sample from the constant temperature bath 6;

[0098] 6) Inject the sample of the mixed suspension to be measured into the sample cell 5, with the liquid level of the sample higher than the position of the detection point of the incident light 4, and then place the sample cell 5 into the thermostat 6 for temperature control operation;

[0099] 7) After the temperature control operation is completed, start the sedimentation particle size test, and collect the signal of the transmitted light 7 changing with time caused by the sedimentation of large particles in the mixed suspension sample; the PD detector 8 transmits the signal of the transmitted light intensity changing with time collected to the PC13 software through the data acquisition unit 12, draws the relationship curve of the transmitted light intensity changing with time, and thus obtains the particle size volume distribution curve of the sedimented large particles, and further calculates D 大 [3,2];

[0100] The typical characteristics of the curve of the transmitted light intensity changing with time are: the transmitted light intensity fluctuates within a small range from the start of the test to a certain moment t0, and this time period is defined as the initial test platform, and the average value of the light intensity of this platform is taken to obtain the initial transmitted light intensity I1; starting from t0, the transmitted light intensity increases with the increase of the test time, and reaches a certain moment t n After that, the transmitted light intensity begins to fluctuate within a small range, and the transmitted light intensity basically no longer changes. Define the time from t n To the end of the test as the stable test platform, and the average value of the light intensity of this platform is taken to obtain the stable transmitted light intensity I2;

[0101] When the transmitted light signal reaches the stable test platform, the sedimentation test is completed. At this time, the large particles in the sample have all sedimented to the bottom of the sample cell, and the non-sedimenting small particles that remain suspended in the sample;

[0102] 8) Start the dynamic light scattering test. The APD detector 11 starts to collect the dynamic light scattering test signal, and controls the light intensity adjustment unit to adjust the light intensity of the incident light 4 so that the scattered light 9 signal is within the linear response range of the APD detector 11; the APD detector 11 transmits the signal of the scattered light intensity changing with time collected to the PC13 software through the data acquisition unit 12, obtains the correlation curve through relevant calculations, and obtains the light intensity distribution curve of the non-sedimenting small particles through multi-exponential fitting, and further obtains the particle size volume distribution curve, and calculates D 小 [3,2];

[0103] 9) Through

[0104]

[0105] It can be deduced that φ 小 , where R is the 1 / 2 optical path, Φ 小 is the total volume fraction of non-sedimenting small particles, and Q e小 is the extinction coefficient of non-sedimenting small particles calculated using the Mie theory;

[0106] Through

[0107]

[0108] Then φ can be derived 大 , Φ 大 is the total volume fraction of the large sedimented particles, and Q e大 is the extinction coefficient of the large sedimented particles calculated using the Mie theory;

[0109] Sum up all the peak areas of the particle size volume distribution calculated by the sedimentation method to obtain S 大 , and sum up all the peak areas of the particle size volume distribution calculated by the dynamic light scattering method to obtain S 小 , taking S 大 : S 小 = φ 小 : φ 大 Obtain the proportional relationship between the particle size distribution curves of the large sedimented particles and the non-sedimented small particles, and integrate them into a single particle size volume distribution curve;

[0110] Step 8) also includes the following calculation steps:

[0111] The dynamic light scattering method uses the autocorrelation technique, and the light intensity distribution of the particle size can be obtained through the multi-exponential fitting method. The fitting formula is as follows:

[0112]

[0113] n is the number of particle size gradings.

[0114] Given n p and A p , in combination with the Mie theory, the volume distribution can be derived from the light intensity distribution to obtain D 小 [3,2].

Claims

1. A particle size measuring device based on the combination of dynamic light scattering method and sedimentation method, characterized in that: It includes a laser, an optical intensity adjustment unit, a sample cell, a thermostat, a PD detector, an optical fiber head, an APD detector, a data acquisition unit, a PC, and a control unit; The laser emits laser light, which irradiates the sample in the sample cell; The sample cell contains a suspension liquid of large particles with sedimentation characteristics and small particles without sedimentation characteristics as the sample to be measured, and the refractive indices and absorption rates of the large particles and small particles are the same; The optical intensity adjustment unit includes a set of attenuation sheets mounted on a rotating wheel driven by a motor for adjusting the intensity of the incident light; The sample cell is a container for holding the sample to be measured; The thermostat reaches the set temperature value according to the command of the control unit, with an accuracy of ±0.1 °C and a range of -15 °C to 120 °C; The PD detector is placed at the 0° angle direction of the laser incident direction. After the incident light passes through the sample cell, it enters the PD detector, and the PD detector is used to detect the transmitted light energy; The optical fiber head is placed at a fixed angle in the laser incident direction; The data acquisition unit is used to receive the signals from the PD detector and the APD detector, and transmit the signals to the PC for calculation; The control unit is used to receive the instructions from the PC side, output a control signal to control the temperature of the thermostat to control the temperature of the test sample, and output a control signal to control the position of the optical intensity adjustment unit to adjust the intensity of the incident light.

2. The particle size measuring device based on the combination of dynamic light scattering method and sedimentation method according to claim 1, characterized in that: The internal cross-section of the sample cell is a square of 10 mm × 10 mm, the optical path length L is 10 mm, the volume of the sample cell is ≥4 ml, and it has a four-sided light-transmitting design, and the material is quartz or K9 glass.

3. The particle size measuring device based on the combination of dynamic light scattering method and sedimentation method according to claim 1, characterized in that: The available fixed angles include: the 90° angle direction of the laser incident direction, or the 160° - 175° angle direction opposite to the laser incident direction. The scattered light enters the APD detector through the optical fiber, and the APD detector is used to detect the scattered light energy.

4. The method for measuring the particle size according to claims 1 to 3, which is an application of a method for measuring the particle size based on the combination of dynamic light scattering method and sedimentation method, is characterized in that: It includes the following measurement steps: 1) Input the parameters required for calculation in the software: the dynamic viscosity η of the sample, the total height h of the sample, the particle density ρ p , the medium density ρ f , the refractive index n of the particles p , the absorption rate A of the particles p , the refractive index n of the medium f etc. for sedimentation particle size testing, dynamic light scattering testing and Mie theory calculation, and start the testing; 2) Inject the blank sample into the sample cell. The blank sample is a sample dispersion medium liquid without particles, and the height of the sample liquid surface is higher than the position of the incident light detection point. Then, place the sample cell in the thermostat for temperature control operation to make the blank sample reach the set temperature; 3) Control the optical intensity adjustment unit to adjust the intensity of the incident laser light so that the intensity of the incident laser light decays within the linear response range of the PD detector. If there are multiple attenuation sheets within the linear range of the PD detector, use the attenuation sheet with the smallest attenuation of the incident laser light intensity within the linear response range of the PD detector for testing; 4) The PD detector collects the transmitted light intensity I0 of the blank sample; 5) Take out the blank sample from the thermostat; 6) Inject the sample of the mixed suspension to be measured into the sample cell. The height of the sample liquid surface is higher than the position of the incident light detection point. Then, place the sample cell in the thermostat for temperature control operation; 7) After the constant temperature operation ends, the sedimentation particle size test begins, and the signal of the transmitted light changing with time caused by the sedimentation of large particles in the mixed suspension sample is collected; the PD detector transmits the signal of the transmitted light intensity changing with time collected through the data acquisition unit to the PC software, plots the relationship curve of the transmitted light intensity changing with time, and thus obtains the particle size volume distribution curve of the sedimented large particles, and further calculates D 大 [3,2]; The typical characteristics of the curve of the transmitted light intensity changing with time are as follows: the transmitted light intensity fluctuates within a small range from the start of the test to a certain moment t0. This time period is defined as the initial test platform, and the average value of the light intensity of this platform is taken to obtain the initial transmitted light intensity I1; starting from t0, the transmitted light intensity increases with the increase of the test time. When it reaches a certain moment t n after that, the transmitted light intensity begins to fluctuate within a small range and the transmitted light intensity basically no longer changes. Define t n to the end of the test as the stable test platform, and the average value of the light intensity of this platform is taken to obtain the stable transmitted light intensity I2; When the transmitted light signal reaches a stable test platform, the sedimentation test is completed. At this time, all the large particles in the sample have settled to the bottom of the sample cell, and the non-sedimenting small particles still suspended in the sample; 8) Start the dynamic light scattering test. The APD detector starts to collect the dynamic light scattering test signal, and control the optical intensity adjustment unit to adjust the intensity of the incident light so that the scattered light signal is within the linear response range of the APD detector; The APD detector transmits the signal of the scattered light intensity collected over time to the PC software through the data acquisition unit, obtains the correlation curve through relevant calculations, and obtains the light intensity distribution curve of non-settling small particles through multi-exponential fitting, further obtains the particle size volume distribution curve, and calculates D 小 [3,2]; 9) Through It can be deduced that φ 小 , where R is 1 / 2 of the optical path, and Φ 小 is the total volume fraction of non-settling small particles, and Q e小 is the extinction coefficient of non-settling small particles calculated using Mie theory; Through Then φ can be deduced 大 , Φ 大 is the total volume fraction of large sedimenting particles, and Q e大 is the extinction coefficient of large sedimenting particles calculated using the Michaelis theory; Sum up all the peak areas of the particle size volume distribution calculated by the sedimentation method to obtain S 大 , sum up all the peak areas of the particle size volume distribution calculated by the dynamic light scattering method to obtain S 小 , with S 大 : S 小 = φ 小 : φ 大 Obtain the proportional relationship between the particle size distribution curves of the sedimented large particles and the non-sedimented small particles, and integrate them into one particle size volume distribution curve.

5. The method for measuring the particle size according to claim 4, which is an application of a method for measuring the particle size based on the combination of dynamic light scattering method and sedimentation method, is characterized in that The following calculation steps are also included in step 8): The dynamic light scattering method uses autocorrelation technology, and the intensity distribution of particle size can be obtained by multi-exponential fitting method. The fitting formula is as follows: n is the number of particle size gradings. Given n p and A p Under the condition, the volume distribution can be deduced from the light intensity distribution in combination with the Mie theory to obtain D 小 [3, 2].

6. The method for measuring particle size according to claim 4, which is based on a method combining dynamic light scattering method and sedimentation method, is characterized in that, This method and device realize the measurement of particle size distribution information in the range of nano to micron of a wide-distribution particle dispersion system in one test process. Among them, the effective detection range of the sedimentation method is 1μm - 50μm, and the effective detection range of dynamic light scattering is particles with a size of 1nm - 1μm.

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