WO2010040257A1

WO2010040257A1 - In situ particle measuring device

Info

Publication number: WO2010040257A1
Application number: PCT/CN2008/072626
Authority: WO
Inventors: 孔兵; 杨宏伟; 范顺杰; 贺伯特·格里布; 蒋俊峰; 卓越
Original assignee: 西门子公司
Priority date: 2008-10-09
Filing date: 2008-10-09
Publication date: 2010-04-15

Abstract

An in situ particle measuring device, for measuring particle size distribution and density of a solution, includes an irradiation unit (130) for generating an incident ray and a receiving unit (150) for receiving an emission ray. An optical path (140) is provided between the irradiation unit (130) and the receiving unit (150), and the solution to be measured fills in the optical path (140). Said in situ particle measuring device further includes a mobile unit (141)l, which is driven to move in the optical path (140) to form a short optical path (140') for measuring particle size distribution, or is driven to move out the optical path (140) to form a long optical path (140'') for measuring particle density.

Description

In-situ particle measuring device

The present invention relates to particle measuring devices, and more particularly to in-situ particle size distribution measurement and density measuring devices. Background technique

In the chemical and pharmaceutical fields, real-time measurement of the density and size distribution of particles is very important; for example, the density of microorganisms affects productivity during fermentation; the density and size of crystals determine the efficacy of the drug.

Existing methods for measuring particle density and size distribution, such as sieving method, sedimentation method, microscopy, etc., usually need to be sampled, so that these methods are only applicable to Offline measurement. The general disadvantage of these existing methods is that they are time consuming and labor intensive.

U.S. Patent 6,098,862 discloses an in situ microscope apparatus. The particles must be visually separable to the detector of the device and scaled up to obtain a clear image of the particle, which makes the device's measurement area small and only suitable for a limited range of particle density measurements.

Existing in-situ measurement methods, especially for in-situ sensors for industrial applications, can only be used to measure the density and size distribution of particles. The same method or device is not suitable for measuring both the density of particles and For measuring the size distribution of particles.

U.S. Patent No. 4,890,920 discloses an in-situ particle size distribution measuring apparatus based on a light scatter method, the apparatus comprising a light source, a collimator, an optical path, a focusing mirror, and a detector. However, the scattered light from the particles in such a device is re-scattered by other particles, causing measurement errors, so the optical path of such a device needs to be designed to be shorter to reduce the error; and such a device is not suitable for use in Measure particle density.

An in situ particle density probe based on an optical absorbance method comprising a light source, a light gap, and a photodetector is disclosed in US Patent Application No. US20050264817 A1. The absorbance in the light gap is related to the density of the particles and can be measured by a photodetector. This probe can only be used to measure particle density and not to measure particle size distribution. Since the particle density is measured based on the absorbance method, the optical path of such a device is used to measure the particle size distribution as described above. The optical path of U.S. Patent No. 4,890,920 is such that light encounters the particles multiple times as it passes through the optical path. The disadvantages of the above-mentioned U.S. Patent No. 4,890,920 and U.S. Patent Application No. US20050264817 A1 are:

1) The optical path is fixed and is not suitable for measuring particle density and measuring particle size distribution in the same device;

2) It is easy to accumulate particles or other pollutants in short light paths;

3) In the in-situ particle density measurement, it is difficult or even impossible to perform zero calibration by reference or blank solution in each monitoring process in the monitoring process. Summary of the invention

In view of the above, it is an object of the present invention to provide an in-situ particle measuring apparatus which is suitable for measuring particle size distribution and density.

In order to achieve the above object, the present invention provides an in-situ particle measuring apparatus for measuring a particle size distribution and density in a solution, comprising an irradiation unit for generating incident light and a receiving unit for receiving the emitted light, the irradiation Forming an optical path between the unit and the receiving unit, the solution to be measured is filled in the optical path, the in-situ particle measuring device further includes a moving unit, and the moving unit is driven into the optical path to form A short path of light that measures the particle size distribution, or is driven out of the path to form a long path for measuring particle density.

According to an aspect of the invention, the moving unit is light transmissive, and the light maintains the original direction of propagation in the moving unit.

According to an aspect of the invention, the length of the short optical path is the sum of the distance from the illumination unit to the mobile unit and the distance from the mobile unit to the receiving unit.

According to an aspect of the invention, the position of the mobile unit between the illumination unit and the reception unit is adjusted such that the distance from the illumination unit to the mobile unit or the distance from the mobile unit to the receiving unit is zero.

According to an aspect of the invention, the in-situ particle measuring device further includes a light emitting unit and a detecting unit, wherein the light emitting unit and the irradiation unit are connected by an optical fiber, and the receiving unit and the detecting unit are connected by a fiber bundle. .

According to an aspect of the invention, the illuminating unit, the moving unit and the receiving unit are disposed in one housing to form a probe. According to an aspect of the invention, the moving unit is fixedly mounted on a rotating shaft, and the rotating shaft is driven to drive the moving unit to move into or out of the optical path.

According to an aspect of the invention, the outer casing of the probe opens a groove corresponding to a position between the irradiation unit and the receiving unit, and the solution to be measured is filled in the optical path through the groove.

According to an aspect of the invention, a light window is disposed at an end of the illumination unit opposite to the receiving unit, and another light window is disposed at an end of the receiving unit opposite to the illumination unit.

The in-situ particle measuring apparatus of the present invention conveniently measures the particle size distribution and density by separately applying a light scattering method and an absorbance method by forming optical paths of different lengths. DRAWINGS

Figure 1 is a schematic view showing the principle of the in-situ particle measuring device of the present invention;

2 is a schematic structural view of an in-situ particle measuring device of the present invention;

3 is a cross-sectional view showing a structure of a specific embodiment of the in-situ particle measuring device of the present invention, wherein a short light path is formed between the irradiation unit and the receiving unit;

Figure 4 is a cross-sectional view showing a structure of a specific embodiment of the in-situ particle measuring device of the present invention, wherein a long light path is formed between the irradiation unit and the receiving unit;

Figure 5 is a schematic diagram showing measurement of particle size distribution according to a light scattering method when a short optical path is formed by applying the in-situ particle measuring device of the present invention;

Fig. 6 is a schematic view showing measurement of particle density by an absorbance method when the in-situ particle measuring apparatus of the present invention is used to form a short optical path and a long optical path, respectively. detailed description

The invention will be described in detail below with reference to the drawings.

The in-situ particle measuring apparatus of the present invention measures the size distribution and density of particles by forming light paths of different lengths, respectively, using a light scattering method and an absorbance method.

Referring to FIG. 1 , the in-situ particle measuring apparatus 100 of the present invention includes a light emitting unit 110 , an illuminating unit 130 , a receiving unit 150 , and a detecting unit 170 . The light emitting unit 110 and the illuminating unit 130 are connected by an optical fiber 120 , and the illuminating unit 130 . An optical path 140 is formed with the receiving unit 150. The optical path 140 is filled with a sample solution of a particle size distribution and density to be measured, and the receiving unit 150 and the detecting unit 170 are connected by a fiber bundle 160. The light emitting unit further includes a laser diode 111 and a coupling lens 112, and the illumination unit 130 further includes a calibration lens 131. The receiving unit 150 further includes a focus lens 151.

The laser diode 111 of the light emitting unit 110 emits light, and the light is coupled into the optical fiber 120 through the coupling lens 112, and transmitted to the illumination unit 130 through the optical fiber 120, in which the illumination unit 130 passes The calibration lens 131 aligns the light into parallel light that propagates in the optical path 140 formed between the illumination unit 130 and the receiving unit 150, and the partially parallel light encounters a sample filled in the optical path 140. The particles in the solution are scattered, and the scattered light and the non-scattered parallel light pass through the sample solution and reach the receiving unit 150. In the receiving unit 150, the arriving light is focused by the focusing lens 151, after focusing The light beam is transmitted to the detecting unit 170 through a fiber bundle 160 disposed at one end on the focal plane of the focusing lens 151 and disposed at the other end in the detecting unit 170, the detecting unit 170 according to the focused Light measures the particle size distribution and density of the sample solution.

Referring to FIG. 2, further, the illuminating unit 130 and the receiving unit 150 are disposed in a casing to form a probe 200. The illuminating unit 130 is connected to the illuminating unit 110 through an optical fiber 120, and the receiving unit 150 passes through an optical fiber. A bundle 160 is coupled to the detection unit 170. The light emitting unit 110 and the detecting unit 170 are connected to the controller 190 to form a control terminal 300. The controller 190 is used to control the opening and closing of the lighting unit 110, and is used to control the measurement of the detecting unit 170.

The in-situ particle measuring device of the present invention is characterized in that the length of the optical path 140 is variable, and a short optical path suitable for measuring the particle size distribution of the solution or a length of the particle density suitable for measuring the solution can be formed according to the needs of the measurement. Light path.

Referring to FIG. 2, in order to realize the optical path 140 having a variable length, a light transmitting unit 141 is disposed in the probe 200, and the light can maintain the original propagation direction in the moving unit 141, and the moving unit 141 passes. The cable 142 is connected to a drive unit 180 disposed in the control terminal 300 and connected to the controller 190. The driving unit 180 is configured to drive the moving unit 141 to move into the optical path 140 between the illumination unit 130 and the receiving unit 150, thereby forming a short optical path, and the sum of the distances of the short element 141 to the receiving unit 150 In a preferred embodiment, by adjusting the position of the moving unit 141 between the illumination unit 130 and the receiving unit 150 such that the distance of the illumination unit 130 to the moving unit 141 or the moving unit 141 to the The distance of the receiving unit 150 is zero, so that the scattered light from a certain particle is prevented from being scattered again by other particles, thereby improving the accuracy of the measurement; the driving unit 180 is further configured to drive the moving unit 141 from the irradiation unit. The optical path 140 between the 130 and the receiving unit 150 is removed to form a long optical path.

Referring to FIG. 3 and FIG. 4, in a specific embodiment of the in-situ particle measuring device of the present invention, a groove 210 is formed at a position corresponding to the outer casing of the probe 200 corresponding to the irradiation unit 130 and the receiving unit 150. The solution can be filled by the groove 210 between the irradiation unit 130 and the receiving unit 150 for measurement. In the embodiment, the moving unit 141 is selected as an optical brick, and the light can maintain the original propagation direction in the light brick. The moving unit 141 is fixedly mounted on a rotating shaft 143, and the rotating shaft 143 is driven by the driving unit 180. In this embodiment, the driving unit 180 is selected as a motor, and the rotating shaft 143 is rotated by the motor to drive the moving unit 141 into the optical path 140 between the illumination unit 130 and the receiving unit 150. Or removed from the optical path 140 between the illumination unit 130 and the receiving unit 150.

Referring to FIG. 3, when the moving unit 141 is moved into the optical path 140 between the illumination unit 130 and the receiving unit 150, the optical path 140 at this time is the short optical path 140, and the length of the short optical path 140 is The sum of the distance from the illuminating unit 130 to the moving unit 141 and the distance between the moving unit 141 and the receiving unit 150, in the present embodiment, preferably, the moving unit 141 is in close proximity to the lighting unit 130, Therefore, the distance from the moving unit 141 to the illuminating unit 130 is zero, thereby preventing scattered light from a certain particle from being scattered again by other particles, thereby improving the accuracy of measurement, in which case the short optical path 140, The length is equal to the distance from the mobile unit 141 to the receiving unit 150.

Referring particularly to FIG. 4, when the moving unit 141 is removed from the optical path 140 between the illumination unit 130 and the receiving unit 150, the optical path 140 at this time is a long optical path 140", and the length of the long optical path 140" is The distance from the illumination unit 130 to the receiving unit 150.

Referring to FIG. 3 and FIG. 4, the in-situ particle measuring device of the present invention further provides an optical window 132 at an end of the illumination unit 130 opposite to the receiving unit 150, at the receiving unit. An optical window 152 is disposed at one end of the 150 opposite to the illumination unit 130. The light in the illumination unit 130 is calibrated into parallel rays through the calibration lens 131, and then enters the short light path 140' or the long light path 140" through the light window 132. After reaching the receiving device 150, the light window 152 is passed through the light window 152. The receiving device 150 is entered and focused by the focusing lens 151. The light windows 132, 152 can effectively prevent sample solutions in the optical path from entering the lighting unit 130 and the receiving unit 150.

The particle size distribution can be conveniently measured by applying the in-situ particle measuring device of the present invention. The density, and by the movement of the moving unit 141 in the optical path, can effectively remove particles or other contaminants accumulated in the optical path.

Referring to Fig. 5, when the in-situ particle measuring apparatus of the present invention forms the short optical path 140, the particle size distribution is measured by a light scattering method. Parallel rays from the illumination unit 130 (not shown) propagate in the short optical path 140, and partially parallel rays are scattered by particles of the sample solution filled in the short optical path 140, for larger volume The particles have a smaller angle of scattering, and for larger particles, the angle of scattering is larger, after focusing by the focusing lens 20, on the fiber bundle 160 disposed on the focal plane of the focusing lens 20. The optical density distribution is determined by the particle size distribution in the sample solution in the short optical path 140'. The particle size distribution in the sample solution can be obtained by deconvolving the optical density distribution by using the Fraunhofer diffraction theory for larger particles, and for smaller particles. The optical density distribution is deconvolved using the MIE scattering theory.

Referring to Fig. 6, when the in-situ particle measuring apparatus of the present invention forms the short optical path 140 and the long optical path 140, respectively, the particle density is measured by an absorbance method. The absorbance method is obtained by the following Lamberts-Beer law. Description: (Equation 1)

among them, /. Is the attenuated light intensity of the light passing through the reference in the optical path or the blank solution (such as steaming water), also known as the transmitted light intensity, J is the light attenuation intensity of the sample solution passing through the light path, ^ is the sample The absorbance of the solution is the absorption coefficient of the sample solution, C is the particle density of the sample solution, and J is the optical path length.

In the existing absorbance-based measurement method, in order to reduce the influence of the light source and the drift of the detector, it is necessary to perform zero correction using a reference or blank solution before each measurement. However, in in-situ measurements, zero calibration is performed only before the monitoring process begins, and in a longer cycle monitoring process, it is difficult or even impossible to measure the particle density multiple times before each measurement. Perform zero correction.

When the in-situ particle measuring device of the present invention is used to form the short optical path 140' and the long optical path 140", respectively, the lengths of the long optical path 140" and the short optical path 140' are respectively assumed to be ^, according to the above equation 1, respectively. : = KCL, (Wancheng 2)

Wherein, /o/ ₂ is the light attenuation intensity of the exiting light of the incident light from the illumination unit 130 passing through the sample solution in the long optical path 140" and the short optical path 140', respectively.

In Equation 4 above, / and / ₂ can be detected by the detection, the absorption coefficient of the sample solution and the optical path lengths ^, 2 are known parameters, so that the particle density C in the sample solution can be conveniently determined. Since the measurement of the particle density using Equation 4 is independent of the intensity of light attenuation after reference or blank solution, the measurement of particle density using the in-situ particle measuring device of the present invention does not require zero correction before each measurement.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are made within the spirit and principles of the present invention, should be included in the present invention. Within the scope of protection.

Claims

Claim

An in-situ particle measuring apparatus for measuring particle size distribution and density in a solution, comprising an irradiation unit (130) for generating incident light and a receiving unit for receiving outgoing light

(150), an optical path (140) is formed between the illumination unit (130) and the receiving unit (150), and a solution to be measured is filled in the optical path (140), wherein: the in-situ particle The measuring device further includes a moving unit (141) that is driven into the optical path (140) to form a short optical path (140, ) for measuring particle size distribution, or driven by the mobile unit (141) The light path (140) is removed to form a long light path (140") for measuring the particle density.

The in-situ particle measuring apparatus according to claim 1, wherein the moving unit (141) is light transmissive, and the light maintains an original propagation direction in the moving unit (141).

The in-situ particle measuring apparatus according to claim 1, wherein a length of the short optical path (140, ) is a distance from the irradiation unit (130) to the moving unit (141) and the length The sum of the distances of the mobile unit (141) to the receiving unit (150).

The in-situ particle measuring apparatus according to claim 3, wherein a position of the moving unit (141) between the irradiation unit (130) and the receiving unit (150) is adjusted such that the irradiation unit (130) The distance to the mobile unit (141) or the large separation of the mobile unit (141) to the receiving unit (150) is zero.

The in-situ particle measuring device according to any one of claims 1 to 4, wherein the in-situ particle measuring device further comprises a light emitting unit (110) and a detecting unit (170), the light emitting unit ( 110) is connected to the illumination unit (130) through an optical fiber (120), and the receiving unit (150) is connected to the detection unit (170) through a fiber bundle (160).

The in-situ particle measuring apparatus according to claim 5, wherein the irradiation unit (130), the moving unit (141), and the receiving unit (150) are disposed in one housing to form a probe (200) .

The in-situ particle measuring device according to claim 6, wherein the moving unit (141) is fixedly mounted on a rotating shaft (143), and the rotating shaft (143) is driven to rotate to drive the moving unit ( 141) moving into or out of the optical path (140).

8. The in-situ particle measuring device according to claim 6, wherein the probe

The outer casing of (200) corresponds to the position between the irradiation unit (130) and the receiving unit (150) a tank (210), the solution to be measured is filled in the light path (140) through the tank (210). The in-situ particle measuring apparatus according to claim 5, wherein a light window (132) is disposed at an end of the irradiation unit (130) opposite to the receiving unit (150), Another optical window (152) is disposed at an end of the receiving unit (150) opposite to the illumination unit (130).