A sample flow cell for nanoparticle detection in a liquid medium

Abstract

The application provides a sample flow cell for nanoparticle detection in liquid medium, and belongs to the technical field of particle detection. The technical problems of unstable flow field, serious stray light interference, inability to monitor the internal flow state in situ, and difficult processing of complex structure of the existing sample flow cell are solved. The pool body is provided with a main flow channel, a detection section located in the middle, and a flow focusing structure composed of a tapered section and an expanding section, which improves the detection efficiency while maintaining the stability of the flow state; the side wall of the detection section is provided with a bonded light window and a light diaphragm, and the outside of the light diaphragm is provided with an auxiliary flow channel; the pool body is also provided with a detection interface for connecting a pressure difference sensor. The flow field of the detection area is optimized through the flow focusing structure, the stray light is effectively absorbed by the black glass diaphragm, and the in-situ monitoring of the internal flow and the flow health state is realized through the pressure difference detection. The overall structure is suitable for injection molding, and has the advantages of high detection performance, strong reliability and low manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of particle detection technology, and more specifically to a sample flow cell for detecting nanoparticles in liquid media. Background Technology

[0002] Optical detection technology for tiny particles (such as nanoparticles) in liquids plays a crucial role in fields with extremely high cleanliness requirements, such as semiconductor manufacturing, pharmaceuticals, and high-purity water monitoring. Its core principle is based on the interaction between particles and light (mainly scattering and absorption). By collecting and analyzing scattered light through laser irradiation, it is possible to achieve real-time, online counting and particle size analysis of particles, which is a key means to ensure the cleanliness of process fluids.

[0003] The methods include laser light scattering, single-particle optical sensing, and dynamic light scattering. Laser light scattering measures the intensity distribution of scattered light at different angles and then calculates the particle size distribution of the particle group. Single-particle optical sensing combines photoresistance and light scattering methods, generating independent signals by passing each particle through the measurement area one by one, thus achieving high-resolution counting and particle size measurement. Dynamic light scattering measures the particle size distribution of submicron to nanoscale particles by measuring the minute fluctuations in the intensity of scattered light caused by the Brownian motion of nanoparticles in the suspension over time.

[0004] These methods are all basically based on flow cells, which, as the core component, are designed to confine the flowing liquid sample to a very small, controllable space to facilitate highly sensitive and stable optical detection. However, existing flow cell structures for this type of detection still have significant limitations:

[0005] Firstly, in the face of the weak scattering signal of small particles, any non-target scattered light from the interface will form a huge background noise. High-power lasers amplify the signal, but also amplify this noise even more severely, resulting in a serious deterioration of the signal-to-noise ratio. Therefore, when a high-power laser source is used to detect submicron particles, the strong stray light generated at the liquid-solid interface will form serious optical noise, masking the target signal and thus interfering with the effective extraction of the small particle signal.

[0006] Secondly, system flow monitoring relies heavily on external sensors, which measure the total flow of the entire pipeline. However, the increase in local flow resistance caused by internal blockages occurring near the monitoring window, at flow channel corners, or in areas where the cross-section suddenly changes is insufficient to directly affect the total flow of the system. Therefore, it is impossible to detect abnormal conditions such as local blockages in the flow channel inside the flow pool.

[0007] Third, the manufacturing of complex three-dimensional flow channels is highly dependent on processes such as precision mechanical cutting and etching. However, processes such as mechanical cutting and etching have the characteristics of "material reduction" and "planarization". When dealing with complex three-dimensional flow channels, they are forced to adopt a compromise path of "separate processing - precision assembly". This naturally brings about the fundamental problems of complex processes, high costs, and difficulty in ensuring batch accuracy stability under the influence of multiple factors such as tool wear, thermal stress, and assembly errors.

[0008] Therefore, there is an urgent need for a flow cell structure that can simultaneously avoid stray light interference, optimize the flow field, suppress noise, realize internal state perception, and is easy to manufacture. Summary of the Invention

[0009] The purpose of this invention is to provide a sample flow cell for the detection of nanoparticles in liquid media, so as to solve the technical problems of unstable flow field in the detection section, severe stray light interference, difficulty in monitoring the internal flow state, and complex structure processing in the prior art.

[0010] The objective of this invention is achieved as follows:

[0011] A flow cell for optical detection of liquid particles includes a cell body, a cell shell, an inlet end, and an outlet end. The cell body is disposed inside the cell shell, and its upper and lower ends are connected to the outlet end and the inlet end, respectively. Both the outlet end and the inlet end are fixedly connected to the cell shell by inlet and outlet fixing plates. The cell body is provided with a main flow channel and auxiliary flow channels located on both sides of the main flow channel. A light window cover is provided on the cell shell, and the collection area is located on one side adjacent to the light window cover.

[0012] The main flow channel and two auxiliary flow channels run longitudinally through the pool body and are connected to the inlet and outlet ends respectively. The main flow channel and the auxiliary flow channels are separated by a partition. An aperture is installed in the auxiliary flow channel. Part of the aperture is connected to the main flow channel through the partition, and the other part is exposed in the auxiliary flow channel. A light window is installed in the pool body at the position corresponding to the aperture, and the position of the light window cover on the outer shell of the pool body corresponds to the position of the light window cover.

[0013] The inlet end includes an inlet flow channel and two inlet capillary channels, and the outlet end includes an outlet flow channel and two outlet capillary channels. The inlet flow channel is connected to the main flow channel, and the inlet capillary channels branch off from both sides of the inlet flow channel and are connected to the two auxiliary flow channels. The outlet flow channel is connected to the main flow channel, and the two outlet capillary channels extend from the auxiliary flow channels and merge into the outlet flow channel.

[0014] In the flow cell of the present invention, a detection section is provided in the middle of the main flow channel, and the detection section is in contact with the aperture.

[0015] In the flow cell of the present invention, a converging section is provided upstream of the detection section and a expanding section is provided downstream. The converging section and the detection section together constitute a flow focusing structure for accelerating and focusing the liquid flow passing through the detection section.

[0016] In the flow tank of the present invention, the main channel of the tank body is integrally formed by injection molding, and the cross-sectional shape of the main channel is designed to be square, which facilitates processing and ensures structural strength.

[0017] In the flow cell of the present invention, the cross-section of the auxiliary flow channel adopts an oblong shape with semi-circular ends and a rectangular middle section, which is convenient for processing and forming;

[0018] In the flow cell of the present invention, the auxiliary flow channel allows a portion of the fluid to flow through the outside of the aperture, which serves to cool the aperture, remove dead zone sedimentation particles, and absorb optical noise.

[0019] In the flow cell of the present invention, an aperture is provided on the aperture, which cooperates with the light window to form an optical path;

[0020] In the flow cell of the present invention, the aperture exposed in the auxiliary flow channel is bonded to the light window, and a gap is maintained between them to form a rinsing tank, which prevents the sedimentation of dead zones of particulate matter and enhances the absorption of stray light.

[0021] In the flow cell of the present invention, the light window is arranged laterally in the cell body and is fastened by the light window cover by threads;

[0022] In the flow cell of the present invention, a first differential pressure detection port is provided before the tapering section on the detection section, and a second differential pressure detection port is provided at the position where the tapering section communicates with the wall of the detection section.

[0023] In the flow pool of the present invention, the channel contraction angle of the tapered section is preferably 20-22°, and the channel expansion angle of the expanding section is preferably 6-8°; this angle design is conducive to forming a stable Venturi tube effect and is friendly to injection molding demolding.

[0024] In the flow pool of the present invention, both the first differential pressure detection port and the second differential pressure detection port are connected to differential pressure sensors, which can monitor the pressure difference between the main flow channel before the tapering section and the detection section in real time, thereby directly reflecting the actual internal flow or diagnosing flow channel abnormalities.

[0025] In the flow cell of the present invention, the cell body is prepared using one of black polyvinyl chloride trifluoroethylene, perfluoroalkoxy, or ethylene-chlorotrifluoroethylene copolymer;

[0026] In the flow cell of the present invention, the outer shell of the cell is made of one of aluminum alloy, titanium alloy, high-strength carbon fiber composite material or glass fiber reinforced polymer.

[0027] In the flow pool of the present invention, the pool body and the pool body shell are firmly joined by an interference fit and fastened by threads;

[0028] In the flow-through pool of the present invention, before the pool body and the pool body shell are assembled, the pool body is first refrigerated and cooled within the range of -10°C to 30°C, and the pool body shell is heated within the range of 80°C to 150°C. After the two are assembled, they are left to stand until both reach room temperature.

[0029] In the flow pool of the present invention, positioning pins are provided on the inlet and outlet fixing plates to fix the orientation of the inlet and outlet ends;

[0030] In the flow cell of the present invention, the aperture is made of one of black glass, black anodized aluminum alloy or black spring steel, and a portion of it extends into the auxiliary flow channel;

[0031] In the flow cell of the present invention, the optical window is prepared using one of the following: quartz, sapphire, nitride window, or special optical glass;

[0032] In the flow cell of this invention, the liquid sample to be tested enters the flow cell through the inlet, and after being accelerated and focused in the converging section, it forms a stable laminar or transitional flow that passes through the detection section; the laser beam shines through the transparent window to irradiate the particles in this area, and the scattered light generated is collected and detected; the aperture effectively absorbs the stray light generated by the liquid-solid interface, and the auxiliary flow channel continuously cools the aperture; the system achieves in-situ sensing of the internal flow rate and flow health status by monitoring the pressure difference between the main flow channel before the converging section and the detection zone.

[0033] The outstanding and beneficial technical effects of this invention compared to the prior art are:

[0034] This invention provides a sample flow cell for detecting nanoparticles in liquid media. A gradually expanding and contracting flow focusing structure optimizes the flow field in the detection zone, significantly reducing particle overlap and improving the accuracy of counting and particle size analysis. A flushing tank is constructed using a bonded aperture and window, which prevents particle sedimentation in dead zones and greatly suppresses stray light interference, improving the signal-to-noise ratio and the ability to detect small particles. The differential pressure detection port design enables in-situ, direct monitoring of the flow rate and flow state within the flow cell, enhancing system reliability and fault diagnosis capabilities. The overall structure fully considers injection molding process requirements; the square flow channel and specific draft angle design make low-cost, mass production of complex three-dimensional flow channels possible, combining high performance, high reliability, and good economic efficiency. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the overall structure of a sample flow cell for detecting nanoparticles in a liquid medium, provided in Embodiment 1 of the present invention.

[0037] Figure 2 This is a frontal cross-sectional view at the center of the detection section of a sample flow cell for detecting nanoparticles in a liquid medium, as provided in Embodiment 1 of the present invention.

[0038] Figure 3 This is a top cross-sectional view of the center of the detection section of a sample flow cell for detecting nanoparticles in a liquid medium, as provided in Embodiment 1 of the present invention.

[0039] Figure 4 This is a schematic diagram of the aperture and transparent window of a sample flow cell for detecting nanoparticles in a liquid medium, provided in Embodiment 1 of the present invention.

[0040] Figure 5 This is a schematic diagram of the bonding between the aperture and the transparent window of a sample flow cell for detecting nanoparticles in a liquid medium, as provided in Embodiment 1 of the present invention.

[0041] Figure 6 This is a schematic diagram of the fluid domain of a sample flow cell for detecting nanoparticles in a liquid medium, as provided in Embodiment 1 of the present invention.

[0042] Figure 7 This is a schematic diagram of the flow velocity distribution on the horizontal plane where the center line of a sample flow cell for detecting nanoparticles in a liquid medium is located, as provided in Embodiment 1 of the present invention.

[0043] Figure 8 This is a schematic diagram of the velocity distribution at the center line in a method for detecting particulate matter in a liquid medium provided in Embodiment 2 of the present invention;

[0044] Figure 9 This is a schematic diagram of the velocity distribution of the centerline at Y=-10μm in the XY plane in a particulate matter detection method in a liquid medium provided in Embodiment 2 of the present invention;

[0045] Figure 10 This is a schematic diagram of the velocity distribution of the centerline at Y=+10μm in the XY plane in a particulate matter detection method in a liquid medium provided in Embodiment 2 of the present invention;

[0046] Figure 11 This is a schematic diagram of the static pressure change at the first differential pressure detection port in a particulate matter detection method in a liquid medium provided in Embodiment 2 of the present invention;

[0047] Figure 12 This is a schematic diagram of the static pressure change at the second differential pressure detection port in a particulate matter detection method in a liquid medium provided in Embodiment 2 of the present invention;

[0048] In the diagram: 10. Pool body; 101. Main channel; 102. Detection section; 103. Gradual narrowing section; 104. Gradual widening section; 105. Auxiliary flow channel; 106. Baffle; 107. First differential pressure detection port; 108. Second differential pressure detection port; 20. Pool shell; 30. Inlet end; 301. Inlet flow channel; 302. Inlet capillary flow channel; 40. Outlet end; 401. Outlet flow channel; 402. Outlet capillary flow channel; 50. Aperture; 501. Aperture through hole; 502. Rinsing tank; 60. Light window; 601. Rear wall of light window; 70. Light window cover; 80. Inlet / outlet fixing plate; 90. Collection area; 100. Positioning pin; 110. Centerline. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0050] Example 1

[0051] This embodiment provides a sample flow cell for the detection of nanoparticles in liquid media, which can suppress stray light and perform in-situ detection of the flow rate in the detection section 102.

[0052] The overall structure of the sample flow cell is as follows: Figure 1 As shown, it includes a pool body 10, a pool body shell 20, an inlet end 30, and an outlet end 40. The pool body 10 is located inside the pool body shell 20, and its upper and lower ends are connected to the outlet end 40 and the inlet end 30, respectively. The outlet end 40 and the inlet end 30 are both fixedly connected to the pool body shell 20 through inlet and outlet fixing plates 80. The pool body 10 is provided with a main flow channel 101 and auxiliary flow channels 105 located on both sides of the main flow channel 101. The pool body shell 20 is provided with a light window cover 70, and the collection area 90 is located on one side adjacent to the light window cover 70.

[0053] The internal structure of pool 10 is as follows Figure 2As shown, the main flow channel 101 and two auxiliary flow channels 105 longitudinally penetrate the pool body 10 and are connected to the inlet end 30 and the outlet end 40 respectively. The main flow channel 101 and the auxiliary flow channels 105 are separated by a partition 106. An aperture 50 is provided in the auxiliary flow channel 105. A part of the aperture 50 is connected to the main flow channel 101 through the partition 106, and the other part is exposed in the auxiliary flow channel 105. A light window 60 is provided in the pool body 10 at the position corresponding to the aperture 50, and the position corresponds to the position of the light window cover 70 on the outer shell 20 of the pool body.

[0054] The inlet end 30 includes an inlet flow channel 301 and two inlet capillary flow channels 302, and the outlet end 40 includes an outlet flow channel 401 and two outlet capillary flow channels 402; wherein the inlet flow channel 301 is connected to the main flow channel 101, the inlet capillary flow channels 302 branch off from both sides of the inlet flow channel 301 and are connected to two auxiliary flow channels 105; the outlet flow channel 401 is connected to the main flow channel 101, and the two outlet capillary flow channels 402 extend from the auxiliary flow channels 105 and merge into the outlet flow channel 401;

[0055] A detection section 102 is provided in the middle of the main channel 101, and the detection section 102 is in contact with the aperture 50. A tapered section 103 is provided upstream of the detection section 102, and a widening section 104 is provided downstream. The channel contraction angle of the tapered section 103 is preferably 20-22°, and the channel expansion angle of the widening section 104 is preferably 6-8°. This angle design is conducive to forming a stable Venturi tube effect and is friendly to injection molding demolding. The tapered section 103 and the detection section 102 together constitute a flow focusing structure, which is used to accelerate and focus the liquid flow passing through the detection section 102.

[0056] The main channel 101 of the pool body 10 is integrally formed by injection molding, and the cross-sectional shape of the main channel 101 is designed to be square, which facilitates processing and ensures structural strength.

[0057] like Figure 3 As shown, the auxiliary flow channel 105 has a waist-shaped hole with semi-circular ends and a rectangular middle section, which is easy to process and form. In addition, a tapered groove space with a 90° opening is left on the side of the optical path, with its central axis aligned with the center of the collection area 90, for mounting the mirror assembly that collects the scattered light signal. Furthermore, the auxiliary flow channel 105 allows a portion of the fluid to flow through the outside of the aperture 50, which cools the aperture 50, removes dead zone sediment particles, and absorbs optical noise.

[0058] The structure of aperture 50 and aperture 60 is as follows Figure 4 and Figure 5As shown, the aperture 50 is provided with an aperture through hole 501, which cooperates with the aperture 60 to form an optical path; the aperture 50 exposed in the auxiliary flow channel 105 is bonded to the aperture 60, and a 1mm gap is maintained between them to form a rinsing tank 502 to prevent the sedimentation of dead zones of particulate matter. The rear wall 601 of the aperture is a liquid-solid interface, which will generate a large amount of stray light. In the bonded structure, the rear wall 601 of the aperture is surrounded on three sides by the rinsing tank 502 of the aperture 50, and the aperture 50 can absorb most of the stray light generated by the rear wall 601 of the aperture; the aperture 60 is arranged laterally in the pool body 10 and is fastened by the aperture cover 70 by threads.

[0059] A first differential pressure detection port 107 is set before the tapering section 103 on the detection section 102, and a second differential pressure detection port 108 is set at the position where the tapering section 103 communicates with the wall of the detection section 102; both the first differential pressure detection port 107 and the second differential pressure detection port 108 are connected to differential pressure sensors, which can monitor the pressure difference between the main flow channel 101 before the tapering section 103 and the detection section 102 in real time, thereby directly reflecting the actual internal flow or diagnosing flow channel abnormalities;

[0060] The pool body 10 is made of one of black polyvinyl chloride trifluoroethylene, perfluoroalkoxy, or ethylene-chlorotrifluoroethylene copolymer; the pool shell 20 is made of one of aluminum alloy, titanium alloy, high-strength carbon fiber composite material, or glass fiber reinforced polymer; the pool body 10 and the pool shell 20 are firmly joined by an interference fit and fastened by threads;

[0061] Before assembling the pool body 10 and the pool body shell 20, the pool body is refrigerated and cooled within the range of -10°C to 30°C, and the pool body shell is heated within the range of 80°C to 150°C. After the two are assembled, they are left to stand until both reach room temperature.

[0062] The positioning pin 100 is set on the inlet and outlet fixing plate to fix the direction of the inlet end 30 and the outlet end 40; the aperture 50 is made of one of black glass, black anodized aluminum alloy or black spring steel, and a part of it extends into the auxiliary flow channel; the light window 60 is made of one of quartz, sapphire, nitride window or special optical glass.

[0063] The liquid sample to be tested enters the flow cell through the inlet. After being accelerated and focused in the converging section, it forms a stable laminar or transitional flow that passes through the detection section. The laser beam shines through the transparent window onto the particles in this area, and the scattered light generated is collected and detected. The aperture effectively absorbs the stray light generated by the liquid-solid interface, and the auxiliary flow channel continuously cools the aperture. The system achieves in-situ sensing of the internal flow rate and flow health status by monitoring the pressure difference between the main flow channel before the converging section and the detection zone.

[0064] The fluid domain extracted from the sample flow cell provided in this embodiment is as follows: Figure 6 As shown, centerline 110 is a straight line coinciding with the optical axis; the velocity distribution on the XY plane containing centerline 110 is as follows. Figure 7 As shown, the velocity distribution in the central collection area 90 of the main channel 101 is uniform and stable.

[0065] Example 2

[0066] This embodiment provides a method for detecting particulate matter in a liquid medium. This method is based on the flow cell described in Embodiment 1. The specific process of detecting particulate matter in a liquid medium using the above-mentioned sample flow cell is described below from two directions: optical path and fluid path.

[0067] In the sample flow cell optical path, the shaped laser beam passes sequentially through the through-hole of the optical window cover 70, through the transparent optical window 60, through the through-hole in the center of the aperture 50, and enters the detection section 102. In the detection section 102, the laser encounters particulate matter in the liquid sample, generating scattered light. This scattered light is collected and analyzed by a collection lens device installed in the lateral collection area 90.

[0068] In the sample flow cell fluid pathway, the liquid sample first enters at inlet 30. Most of the liquid sample enters the main flow channel 101 through inlet channel 301, then passes through the converging section 103, detection section 102, and expanding section 104, before exiting through outlet 40. Particulate matter in this portion of the liquid sample is struck by the laser in the collection area 90 of the detection section 102, generating stray light signals. The remaining small portion of the liquid sample enters the auxiliary flow channel 105 through inlet capillary channel 302 in inlet 30, and then re-merges with the liquid sample through outlet capillary channel 402 in outlet 40.

[0069] The auxiliary flow channel 105 plays three key roles:

[0070] (1) The main channel 101 and the auxiliary channel 105 exchange liquid stably and slowly through the aperture 501 to prevent particulate matter from settling in the dead zone.

[0071] (2) Cool the aperture by 50°;

[0072] (3) The liquid in the auxiliary flow channel 105 can absorb some of the optical noise such as diffraction light and scattered light.

[0073] During operation, by connecting a differential pressure sensor between the first differential pressure detection port 107 and the second differential pressure detection port 108, the pressure difference between the vicinity of the inlet of the converging section 103 and the detection section 102 can be measured in real time. This differential pressure value directly reflects the actual flow state inside the flow cell. This differential pressure signal can be used to directly monitor the internal flow rate or diagnose abnormalities such as local blockage of the flow channel, realizing in-situ detection of the health status of the flow cell.

[0074] The flow cell of the sample was simulated and analyzed under the condition that the flow rate was set to 1 L / min; when the flow rate was set to 1 L / min, the theoretically calculated pressure difference (without considering the influence of factors such as wall surface and viscosity, i.e., under ideal conditions) was about 867 Pa.

[0075] Velocity distribution at the centerline and within ±10μm as follows Figure 8 , Figure 9 and Figure 10 As shown, the flow velocity is uniformly and stably distributed within a 10 μm range around the centerline.

[0076] The static pressure change at the first differential pressure detection port 107 is as follows: Figure 11 As shown, under stable flow conditions, the static pressure at the first differential pressure detection port 107 is approximately 2848 Pa; the static pressure variation at the second differential pressure detection port 108 is as follows. Figure 12 As shown, the static pressure of the second differential pressure detection port 108 is approximately 2078 Pa.

[0077] Therefore, a constant pressure difference of 770 Pa exists between the two differential pressure detection ports. By connecting a high-precision differential pressure sensor, differential pressure detection or monitoring can be achieved, thereby enabling in-situ measurement or monitoring of the flow rate in the collection area. The flow rate signal can be used for closed-loop control of the flow control system, while the differential pressure signal can be used for filtering particle detection data.

[0078] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sample flow cell for detecting nanoparticles in a liquid medium, characterized in that, The flow pool includes a pool body (10), a pool body shell (20), an inlet end (30), and an outlet end (40). The pool body (10) is set inside the outer shell (20) of the pool body. The upper and lower ends of the pool body (10) are respectively connected to the outlet end (40) and the inlet end (30). The outlet end (40) and the inlet end (30) are both fixedly connected to the upper and lower ends of the outer shell (20) of the pool body through the inlet and outlet fixing plates (80). The pool body (10) is provided with a main channel (101) and two auxiliary channels (105) inside, and the two auxiliary channels (105) are located on both sides of the main channel (101); an aperture (50) is provided in the auxiliary channel (105), a part of the aperture (50) is connected to the main channel (101) through a partition (106), and the other part is exposed in the auxiliary channel (105). A detection section (102) is provided in the middle of the main channel (101). 02) Contact with the aperture (50); A light window (60) is provided in the pool body (10) at the position corresponding to the aperture (50), and an aperture through hole (501) is provided on the aperture (50) to cooperate with the light window (60) to realize an optical path; The aperture (50) exposed in the auxiliary flow channel (105) is bonded to the light window (60), and a gap is maintained between the two to form a rinsing tank (502). The rinsing tank (502) prevents the sedimentation of dead zones of particulate matter and absorbs stray light; A light window cover (70) is provided on the outer shell (20) of the pool body corresponding to the position of the light aperture (50), and a collection area (90) is provided on one side of the outer shell (20) adjacent to the light window cover (70); the flow cell detects particulate matter in the liquid medium by analyzing the scattered light collected by the collection area (90).

2. The flow-through pool according to claim 1, characterized in that, The main flow channel (101) and the auxiliary flow channel (105) pass through the pool body (10) and are connected to the inlet end (30) and the outlet end (40) respectively. The two auxiliary flow channels (105) are separated from the main flow channel (101) by partitions (106); The main channel (101) is integrally formed by injection molding, and the cross-section of the main channel (101) is square; the cross-section of the auxiliary channel (105) adopts an oblong hole shape.

3. The flow-through pool according to claim 2, characterized in that, The main channel (101) is provided with a tapering section (103), a detection section (102) and a widening section (104). The flow channel contraction angle of the tapering section (103) is in the range of 20-22°, and the flow channel expansion angle of the expanding section (104) is in the range of 6-8°; the tapering section (103) and the detection section (102) constitute a flow focusing structure with Venturi effect, which is used to accelerate and focus the liquid flow passing through the detection section (102).

4. The flow-through pool according to claim 3, characterized in that, The inlet end (30) includes an inlet channel (301) and inlet capillary channels (302) distributed on both sides of the inlet channel (301). The inlet channel (301) is connected to one end of the main channel (101), and the inlet capillary channels (302) are branched off from the inlet channel (301) and connected to one end of two auxiliary channels (105). The outlet end (40) includes an outlet flow channel (401) and outlet capillary flow channels (402) distributed on both sides of the outlet flow channel (401). The outlet flow channel (401) is connected to the other end of the main flow channel (101). The outlet capillary flow channels (402) extend from the other ends of the two auxiliary flow channels (105) and converge into the outlet flow channel (401).

5. The flow-through pool according to claim 4, characterized in that, A first differential pressure detection port (107) is provided at the beginning of the tapering section (103) of the main channel (101), and a second differential pressure detection port (108) is provided at the position where the detection section (102) of the main channel (101) contacts the tapering section (103). The first differential pressure detection port (107) and the second differential pressure detection port (108) are respectively connected to differential pressure sensors to monitor the pressure difference between the beginning of the tapering section (103) and the detection section (102) on the main channel (101) in real time.

6. The flow-through cell according to claim 5, characterized in that, The pool body (10) is made of black polyvinyl chloride, perfluoroalkoxy, or One of the preparations is obtained; The outer shell (20) of the pool body is made of one of aluminum alloy, titanium alloy, carbon fiber composite material or glass fiber reinforced polymer; The pool body (10) and the pool body shell (20) are joined by an interference fit and fastened by threads.

7. The flow-through cell according to claim 6, characterized in that, The optical window (60) is prepared using one of the following: quartz, sapphire, or nitride window. The aperture (50) is made of one of the following: black glass, black anodized aluminum alloy or black spring steel.

8. The flow-through cell according to claim 7, characterized in that, The inlet and outlet fixing plate (80) is fixed to the outer shell (20) of the pool body by positioning pin (100).

9. The flow-through cell according to claim 8, characterized in that, A collection lens device is installed on the collection area (90) to collect the scattered light generated by particulate matter in the liquid sample for analysis.

Images