Sheath flow impedance particle counting device and detection method

Abstract

The present invention discloses a sheath flow electrical impedance particle counting device and a detection method, wherein the sheath flow electrical impedance particle counting device includes a sheath flow forecell and a sheath flow backcell, the sheath flow forecell and the sheath flow backcell being connected through a counting hole to form a particle path, the sheath flow forecell being provided with a forecell electrode, a sample needle, a sheath liquid inlet, and a forecell flushing inlet, the sample needle being used to transport the sample liquid into the sheath flow forecell; the sheath flow backcell being provided with a backcell electrode, a backcell flushing inlet, and a backcell flushing outlet; the forecell flushing inlet and the backcell flushing inlet both face the counting hole, the backcell flushing inlet is located below the X-horizontal plane passing through the central axis of the counting hole, and the backcell electrode is a solid cylindrical structure or a hollow cylindrical structure. The sheath flow electrical impedance particle counting device of the present invention is easy to flush, and can prevent bubbles generated from being hidden in the electrode sheet during backcell flushing.

Description

Technical Field

[0001] The present invention relates to the field of sheath flow impedance counting, and in particular to a sheath flow impedance particle counting device and a detection method. Background Art

[0002] The principle of sheath flow impedance counting is to arrange the particles to be measured, suspended in an electrolyte, one at a time through a small hole (gem hole). An electrode (one positive and one negative) is installed on each side of the hole. The positive and negative electrodes are connected through the electrolyte before and after the hole (gem hole) to form a constant current source. When the particles to be measured pass through the hole, the overall conductivity of the electrolyte will change, causing the resistance to change and generating a corresponding voltage pulse signal. The sheath flow impedance back cell electrode (positive electrode) is generally made of platinum sheet or platinum wire. When using platinum wire, high-voltage burning function can be achieved. High-voltage burning removes residual protein and keeps the gem hole unobstructed. If the burning function is not considered, the platinum sheet is selected as the positive electrode.

[0003] The current sheath flow impedance particle counting device has the problem of being easily flushed and affecting subsequent detection. In addition, the sheath flow impedance back cell electrode is generally installed in the form of a platinum sheet. If the position is not installed properly, it is easy for the bubbles generated during the back cell flushing to be hidden in the electrode sheet, and it will also hinder the flow of fluid and reduce the flushing capacity of the back cell.

[0004] In view of this, it is necessary to provide a sheath flow electrical impedance particle counting device and detection method to solve or at least alleviate the above-mentioned defects. Summary of the Invention

[0005] In order to solve the existing technical problems, the present invention provides a sheath flow electrical impedance particle counting device that is easy to flush.

[0006] To achieve the above-mentioned purpose, the technical solution of the embodiment of the present invention is implemented as follows:

[0007] A sheath flow impedance particle counting device includes a sheath flow forecell and a sheath flow backcell, the sheath flow forecell and the sheath flow backcell being connected through a counting hole to form a particle path, the sheath flow forecell being provided with a forecell electrode, a sample needle, a sheath liquid inlet and a forecell flushing inlet, the sample needle being used to transport the sample liquid into the sheath flow forecell; the sheath flow backcell being provided with a backcell electrode, a backcell flushing inlet and a backcell flushing outlet; the forecell electrode and the backcell electrode jointly form a current loop for particle detection; the forecell flushing inlet and the backcell flushing inlet both face the counting hole, the backcell flushing inlet is located below the X horizontal plane passing through the central axis of the counting hole, and the backcell electrode is a solid cylindrical structure or a hollow cylindrical structure.

[0008] Preferably, the rear cell electrode is a corrosion-resistant structure, or a corrosion-resistant layer is provided on the surface of the rear cell electrode.

[0009] Preferably, the rear cell electrode is a hollow cylindrical structure, the rear cell electrode is coaxially arranged with the counting hole, and the rear cell electrode serves as a sample waste liquid collection tube.

[0010] Preferably, the back cell electrode is a solid cylindrical structure, and a sample waste liquid collection tube is further provided on the sheath flow back cell, with the tube opening of the sample waste liquid collection tube facing the counting hole.

[0011] Preferably, the rear cell electrode and the sample waste liquid collection tube are spaced apart, and the central axis of the rear cell electrode is parallel to the central axis of the sample waste liquid collection tube.

[0012] Preferably, the rear cell flushing inlet is located below the sample waste liquid collection tube, and the outer periphery of the rear cell electrode and the outer periphery of the sample waste liquid collection tube do not overlap in a direction perpendicular to the X horizontal plane.

[0013] Preferably, the distance between the central axis of the rear cell electrode and the central axis of the sample waste liquid collection tube in a direction parallel to the X horizontal plane is greater than the sum of the radius of the rear cell electrode and the radius of the sample waste liquid collection tube.

[0014] Preferably, the rear pool flushing inlet and the rear pool flushing outlet are located in the same vertical plane; or, the central axis of the rear pool flushing inlet is set at a preset angle to the X horizontal plane, and the central axis of the rear pool flushing outlet is perpendicular to the X horizontal plane.

[0015] Preferably, the front pool flushing inlet and the sheath fluid inlet are located in the same vertical plane; or, the central axis of the front pool flushing inlet is set at a preset angle to the X horizontal plane, and the central axis of the sheath fluid inlet is perpendicular to the X horizontal plane.

[0016] Preferably, the front pool flushing inlet and the rear pool flushing inlet are symmetrically arranged relative to a vertical plane perpendicular to the central axis of the counting hole, and / or the sheath fluid inlet and the rear pool flushing outlet are symmetrically arranged relative to a vertical plane perpendicular to the central axis of the counting hole.

[0017] In addition, the present invention also provides a detection method, which is applied to the sheath flow electrical impedance particle counting device as described above, and the detection method comprises the following steps:

[0018] delivering the sample liquid into the sheath flow forecell through the sample needle;

[0019] The sheath liquid is fed into the sheath flow forecell through the sheath liquid inlet, and the sheath liquid wraps around the particles in the sample liquid so that the particles pass through the counting hole one by one and generate an electrical signal;

[0020] The number and volume information of sample particles are obtained by counting and analyzing the electrical signals.

[0021] In the above-mentioned embodiment of the present application, the counting cell includes a sheath flow forecell and a sheath flow backcell, and the sheath flow forecell and the sheath flow backcell are connected through a counting hole to form a particle passage, and the sample particles in the sheath flow forecell can flow into the sheath flow backcell through the counting hole. The sheath flow forecell is provided with a forecell electrode, a sample needle, a sheath liquid inlet and a forecell flushing inlet, and the sheath flow backcell is provided with a backcell electrode, a backcell flushing inlet, a backcell flushing outlet and a sample liquid outlet. The sample particles are introduced into the sheath flow forecell through the sample needle, and the sample particles enter the sheath flow backcell through the counting hole under the wrapping of the forecell sheath liquid, and then are discharged to the outside of the sheath flow backcell through the sample liquid outlet. When the sample particles pass through the counting hole, the overall conductivity of the electrolyte will change, thereby causing the resistance to change and generating a corresponding voltage pulse signal, which is acquired by the counting circuit. The front pool flushing inlet and the back pool flushing inlet are both oriented toward the counting hole, so that the front pool flushing liquid injected into the sheath flow front pool through the front pool flushing inlet can flush the side of the counting hole close to the sheath flow front pool, and at the same time, the back pool flushing liquid injected into the sheath flow back pool through the back pool flushing inlet can flush the side of the counting hole close to the sheath flow back pool. In addition, in order to avoid the situation where the back pool electrode hides bubbles, the back pool electrode is a solid cylindrical structure or a hollow cylindrical structure to reduce the flow resistance of the back pool flushing liquid in the sheath flow back pool, so that the fluid in the sheath flow back pool is subjected to the least resistance and the dead angle where bubbles can hide is minimized, thereby avoiding bubbles adhering to or being stored at the back pool electrode to affect the accuracy of the sheath flow impedance detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front cross-sectional view of a first embodiment of the sheath flow electrical impedance particle counting device of the present application;

[0023] Figure 2 This is a front cross-sectional view of a second embodiment of the sheath flow electrical impedance particle counting device of the present application.

[0024] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, reference is made to "some embodiments", which describes a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0026] It should also be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "inner," "outer," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0027] See also Figure 1 and attached Figure 2 An embodiment of the present application provides a sheath flow impedance particle counting device, comprising a counting cell and a counting circuit connected to the counting cell, wherein the counting cell comprises a sheath flow forecell 100 and a sheath flow aftercell 200, the sheath flow forecell 100 and the sheath flow aftercell 200 being connected through a counting hole 300 to form a particle passage, the sheath flow forecell 100 being provided with a forecell electrode 110, a sample needle 120, a sheath liquid inlet and a forecell flushing inlet 130, the forecell electrode 110 being used to connect to the negative electrode of a constant current source, thereby connecting the forecell sheath liquid to the negative electrode, and at the same time, the forecell electrode 110 can also serve as an input port for the forecell sheath liquid, that is, the sheath liquid inlet is directly set at the port of the forecell electrode 110; the sample needle 120 is used to transport the sample particle suspension into the sheath flow forecell 100. The sheath flow back cell 200 is provided with a back cell electrode 210, a back cell flushing inlet 220, a back cell flushing outlet 230 and a sample liquid outlet. The back cell electrode 210 is used to connect to the positive electrode of the constant current source, thereby connecting the fore cell sheath liquid to the positive electrode. The back cell flushing inlet 220 is used to introduce a diluent (back cell cleaning liquid) to flush the counting hole 300 at the sheath flow back cell 200. The back cell flushing outlet 230 is used to discharge the flushing waste liquid or bubbles of the sheath flow back cell 200. The sample particles entering the sheath flow back cell 200 are discharged from the sample liquid outlet to prevent the particles from flowing back to the counting hole 300 and interfering with the particle counting. The fore cell electrode 110 and the back cell electrode 210 are both electrically connected to the counting circuit, and the fore cell flushing inlet 130 and the back cell flushing inlet 220 are both facing the counting hole 300. The rear cell flushing inlet 220 is located below the X horizontal plane passing through the central axis of the counting hole 300 , and the rear cell electrode 210 is a solid cylindrical structure or a hollow cylindrical structure.

[0028] Wherein, the front pool flushing inlet 130 and the back pool flushing inlet 220 are both oriented toward the counting hole 300, so that the front pool flushing liquid injected into the sheath flow front pool 100 through the front pool flushing inlet 130 can flush the side of the counting hole 300 close to the sheath flow front pool 100, and at the same time, the back pool flushing liquid injected into the sheath flow back pool 200 through the back pool flushing inlet 220 can flush the side of the counting hole 300 close to the sheath flow back pool 200. The front pool flushing liquid and the back pool flushing liquid can be diluted sheath liquid, which can be used to flush the counting hole 300 after each test is completed to ensure the accuracy of the next test. After the front pool flushing liquid has flushed the counting hole 300, it flows out from the sheath liquid inlet, and after the back pool flushing liquid has flushed the counting hole 300, it flows out from the back pool flushing outlet 230.

[0029] Among them, the back pool electrode 210 is a solid cylindrical structure or a hollow cylindrical structure to reduce the flow resistance of the back pool flushing liquid in the sheath flow back pool, so that the fluid in the sheath flow back pool is subjected to the least resistance and the dead angle where bubbles can hide is minimized. In this embodiment, the back pool electrode 210 is a solid or hollow cylindrical structure, and also includes a case where the middle part is a cylindrical structure, and the two ends or one end are cut into a conical structure for installation or detection requirements. In addition, the solid cylindrical structure is better than the sheet structure, and the solid cylindrical structure has lower installation direction requirements as a rotating body, and the strength is also higher than the sheet structure, and it is not easy to deform. The hollow cylindrical structure of the back pool electrode has the conductive function of the back pool electrode, and the hollow cylindrical structure also has the function of collecting sample waste liquid in the sample waste liquid collection tube, thereby eliminating the need for a separate installation electrode component, saving material relative to the solid cylindrical structure. The back pool electrode 210 is preferably a corrosion-resistant structure, or a corrosion-resistant layer is provided on the surface of the back pool electrode 210. The rear cell electrode 210 may be an inert metal structure resistant to electrochemical corrosion, or a corrosion-resistant layer may be provided on the surface of the rear cell electrode 210 , and the corrosion-resistant layer may be made of an inert metal material resistant to electrochemical corrosion.

[0030] In the above-described embodiment of the present application, the counting cell includes a sheath flow forecell 100 and a sheath flow backcell 200. The sheath flow forecell 100 and the sheath flow backcell 200 are connected by a counting hole 300 to form a particle passage. Sample particles in the sheath flow forecell 100 can flow into the sheath flow backcell 200 through the counting hole 300. The sheath flow forecell 100 is provided with a forecell electrode 110 and a sample needle 120. The sheath flow backcell 200 is provided with a backcell electrode 210, a backcell flushing inlet 220, a backcell flushing outlet 230, and a sample liquid outlet. Sample particles are introduced into the sheath flow forecell 100 through the sample needle 120. The sample particles, wrapped in the forecell sheath liquid, pass through the counting hole 300 into the sheath flow backcell 200 and are then discharged out of the sheath flow backcell 200 through the sample liquid outlet. When the sample particles pass through the counting hole 300, the overall conductivity of the electrolyte changes, thereby causing a change in resistance and generating a corresponding voltage pulse signal, which is captured by the counting circuit. The front cell flushing inlet 130 and the back cell flushing inlet 220 are both oriented toward the counting hole 300, allowing the front cell flushing liquid to better flush the side of the counting hole 300 that is close to the sheath flow front cell 100, while the back cell flushing liquid can better flush the side of the counting hole that is close to the sheath flow back cell 200. In addition, to prevent the back cell electrode 210 from harboring bubbles, the back cell electrode 210 is a solid cylindrical structure or a hollow cylindrical structure to reduce the flow resistance of the back cell flushing liquid in the sheath flow back cell, thereby minimizing the resistance to the fluid in the sheath flow back cell and minimizing the dead angle where bubbles can hide, thereby preventing bubbles from adhering to or being stored at the back cell electrode and affecting the accuracy of the sheath flow impedance detection results.

[0031] In the attached Figure 1 In the illustrated embodiment, the back-cell electrode 210 is hollow cylindrical and coaxially arranged with the counting hole 300. The sample liquid outlet is a hollow hole in the back-cell electrode 210. In this embodiment, since the back-cell electrode 210 is hollow cylindrical, its outer surface can reduce the flow resistance of the back-cell flushing liquid in the sheath flow back-cell. The central inner hole can serve as the sample liquid outlet to guide sample particles out, eliminating the need for a separate guide tube, optimizing the overall structural layout and saving materials. The cylindrical outer surface can prevent the adhesion of bubbles, and the back-cell electrode 210 can reduce fluid resistance regardless of the angle at which it is installed.

[0032] In the attached Figure 2In the illustrated embodiment, the back cell electrode 210 is a solid cylindrical structure. A sample waste liquid collection tube 240 is also provided on the sheath flow back cell 200. The nozzle of the sample waste liquid collection tube 240 faces the counting hole 300, and the sample liquid outlet is a hollow hole in the sample waste liquid collection tube 240. In this embodiment, the back cell electrode 210 is a solid cylindrical structure. The cylindrical outer surface prevents the adhesion of bubbles, and regardless of the angle at which the back cell electrode 210 is installed, it can reduce fluid resistance. Furthermore, the cylindrical structure has strong bending resistance and is not easily bent due to operational errors during installation. Furthermore, to guide the outflow of sample particles, a separate sample waste liquid collection tube 240 can be provided. The nozzle of the sample waste liquid collection tube 240 faces the counting hole 300, and sample particles flow out of the sheath flow back cell 200 through the waste liquid collection tube 240.

[0033] Furthermore, the back cell electrode 210 is spaced apart from the sample waste liquid collection tube 240, and the length direction of the back cell electrode 210 is parallel to the length direction of the sample waste liquid collection tube 240. The back cell electrode 210 and the sample waste liquid collection tube 240 are both arranged near the center of the sheath flow back cell 200, and the back cell electrode 210 and the sample waste liquid collection tube 240 are spaced apart and adjacent to each other. The length direction of the back cell electrode 210 being parallel to the length direction of the sample waste liquid collection tube 240 facilitates reducing the overall fluid resistance within the sheath flow back cell 200. The axis of the sample needle 120 and the axis of the sample waste liquid collection tube 240 are both collinear with the axis of the counting hole 300. The collinear arrangement of the axis of the sample needle 120 and the axis of the counting hole 300 facilitates the smooth entry of sample particles exiting the sample needle 120 into the counting hole 300, and the outlet of the sample needle 120 is disposed near the counting hole 300. The sheath fluid within the sheath flow forecell 100 and the sheath flow backcell 200 is a particle-free conductive liquid source. The pressure of the forecell sheath fluid is equal to the pressure of the sample flow at the exit of the sample needle 120, while the pressure of the backcell sheath fluid is less than that of the forecell sheath fluid. As a result, the forecell sheath fluid envelops the sample flow and flows into the backcell sheath fluid. Furthermore, the axis of the waste sample collection tube 240 is collinear with the axis of the counting aperture 300, allowing the particle sample flow passing through the counting aperture 300 to enter the waste sample collection tube 240 smoothly, preventing particles from flowing back into the counting aperture 300 and interfering with particle counting.

[0034] As a specific embodiment of the present invention, an electrode mounting hole is provided on the end of the sheath flow backcell 200 that is away from the counting hole 300 and that cooperates with the backcell electrode 210. One end of the backcell electrode 210 is located within the sheath flow backcell 200, and the other end of the backcell electrode 210 is located outside the sheath flow backcell 200. The backcell electrode 210 is fixed to the sheath flow backcell 200 through the electrode mounting hole, or the backcell electrode 210 is integrally formed with the sheath flow backcell 200. One end of the backcell electrode 210 is located within the sheath flow backcell 200 to communicate with the backcell sheath fluid, and the other end of the backcell electrode 210 is located outside the sheath flow backcell 200 to connect to the cross-flow source.

[0035] Furthermore, the counting hole 300 is formed on a synthetic ruby ​​sheet, with an inner diameter and depth of less than 100 microns. The synthetic ruby ​​sheet is mounted between the sheath flow forecell 100 and the sheath flow backcell 200. The sample needle 120 has a through hole along its axis, providing a path for injecting sample particles into the sheath flow forecell 100. The sheath flow forecell 100 has two inlets leading into the interior: one for the sample needle 120 and the other for the sheath fluid inlet.

[0036] Preferably, the rear pool flushing inlet 220 is located below the sample waste liquid collection tube 240. To put it another way, the rear pool flushing inlet 220 can be set at any position below the X horizontal plane. The outer periphery of the rear pool electrode 210 and the outer periphery of the sample waste liquid collection tube 240 do not overlap in a direction perpendicular to the X horizontal plane to reduce or avoid the hiding of bubbles. Furthermore, the distance between the central axis of the rear pool electrode 210 and the central axis of the sample waste liquid collection tube 240 in a direction parallel to the X horizontal plane is greater than the sum of the radius of the rear pool electrode 210 and the radius of the sample waste liquid collection tube 240, so that there is a gap between the rear pool electrode 210 and the sample waste liquid collection tube 240 in the left and right directions, so that the liquid entering the rear pool flushing inlet 220 can be flushed through this gap.

[0037] Preferably, the portion of the sheath flow forepool 100 close to the counting hole 300 is tapered, and / or the portion of the sheath flow backpool 200 close to the counting hole 300 is tapered. The tapered portion of the sheath flow forepool 100 close to the counting hole 300 can speed up the flow rate in the portion close to the counting hole 300, while guiding the sample flow toward the counting hole 300. When the sample liquid in the sheath flow forepool 100 approaches the counting hole 300, its width will be gradually compressed, and the distance between the sample particles in the sample liquid will also be gradually lengthened. The forepool sheath flow formed by the forepool sheath liquid wraps around the particles in the sample liquid and passes through the counting hole 300 one by one, and is discharged from the sample liquid outlet of the sheath flow backpool 200. The tapered portion of the sheath flow backpool 200 close to the counting hole 300 has a similar effect.

[0038] As a specific embodiment of the present invention, the central axis of the back-pool flush inlet 220 is positioned at a preset angle to the horizontal plane X, while the central axis of the back-pool flush outlet 230 is perpendicular to the horizontal plane X. In this embodiment, the centerline of the back-pool flush inlet 220 forms a preset angle with the central axis of the counting aperture 300. The preset angle can be 20-80°, preferably 45° or 60°. The centerline of the back-pool flush inlet 220 can be positioned at any position on the rotation plane below the central axis of the counting cell. The central axis of the back-pool flush outlet 230 is perpendicular to the horizontal plane X to facilitate bubble discharge. Similarly, the forepool flush inlet and the sheath fluid inlet can also be located in the same vertical plane. The sheath fluid inlet, serving as the outlet for sheath fluid in the forepool, is located in the same vertical plane as the forepool flush inlet to reduce fluid resistance within the forepool of sheath flow. Furthermore, the central axis of the forepool flush inlet 130 is positioned at a preset angle to the horizontal plane X, while the central axis of the sheath fluid inlet is perpendicular to the horizontal plane X. The preset angle can be 20-80°, preferably 45° or 60°. Preferably, in order to ensure the symmetry of the structure, the front pool flushing inlet 130 and the rear pool flushing inlet 220 are symmetrically arranged relative to the vertical plane perpendicular to the central axis of the counting hole 300, and / or the sheath liquid inlet and the rear pool flushing outlet 230 are symmetrically arranged relative to the vertical plane perpendicular to the central axis of the counting hole 300.

[0039] In addition, the present invention also provides a detection method, which is applied to the sheath flow impedance counting device as described above, and the sheath flow impedance counting device may also include a sample liquid syringe, a forecell sheath liquid syringe, a forecell flushing syringe, and a backcell flushing syringe; the sample liquid syringe is connected to the input end of the sample needle 120, the forecell sheath liquid syringe is connected to the sheath liquid inlet (at the port of the forecell electrode 110), the forecell flushing syringe is connected to the forecell flushing inlet 130, and the backcell flushing syringe is connected to the backcell flushing inlet 220; the detection method comprises the following steps:

[0040] S10, controlling the sample liquid syringe to deliver the sample liquid into the sheath flow forecell 100 through the sample needle 120, and simultaneously controlling the forecell sheath liquid syringe to deliver the forecell sheath liquid into the sheath flow forecell 100 through the sheath liquid inlet, so that the forecell sheath flow formed by the forecell sheath liquid wraps the particles in the sample liquid and passes through the counting hole 300 one by one;

[0041] Wherein, the sample liquid and the forepool sheath liquid can obtain a boosting force by connecting an air pump, a liquid pump or other pressure source. After the sample liquid and the forepool sheath liquid are injected into the sheath flow forepool 100, there is a flow velocity difference between the sample liquid and the forepool sheath liquid, forming a laminar flow. One end of the sheath flow forepool 100 close to the counting hole 300 can be set as a conical fluid acceleration end, so that the width of the sample liquid in the sheath flow forepool 100 will be gradually compressed when it approaches the counting hole 300, and the spacing between the sample particles in the sample liquid will also be gradually lengthened. The forepool sheath flow formed by the forepool sheath liquid wraps the particles in the sample liquid through the counting hole 300 one by one.

[0042] S20 , the counting circuit calculates data of sample particles by acquiring potential changes of the front cell electrode 110 and the back cell electrode 210 .

[0043] Because the electrolyte between the front cell electrode 110 and the rear cell electrode 210 is connected through the counting aperture 300, a constant current source is formed. When sample particles pass through the counting aperture 300, the overall conductivity of the electrolyte changes, causing a change in resistance and generating a corresponding voltage pulse signal. The counting circuit detects the potential changes of the front cell electrode 110 and the rear cell electrode 210 and calculates relevant data about the sample particles using a preset algorithm.

[0044] Furthermore, the detection method may further include:

[0045] S30, control the front pool flushing syringe to let the front pool flushing liquid enter the sheath flow front pool 100 through the front pool flushing inlet 130 to flush the side of the counting hole 300 close to the sheath flow front pool 100; control the back pool flushing syringe to let the back pool flushing liquid enter the sheath flow back pool 200 through the back pool flushing inlet 220 to flush the side of the counting hole 300 close to the sheath flow back pool 200.

[0046] The front pool flushing liquid enters the sheath flow front pool 100 from the front pool flushing inlet 130 and flushes the counting hole, and flows upward and is discharged from the sheath liquid inlet. The back pool flushing liquid enters the sheath flow back pool 200 from the back pool flushing inlet 220 and flushes the counting hole 300, and flows upward and is discharged from the back pool flushing outlet. The back pool flushing liquid passes through the back pool flushing inlet 220 toward the counting hole 300 and flows upward and is discharged from the back pool flushing outlet 230, and the back pool electrode 210 is a solid cylindrical structure or a hollow cylindrical structure, which can minimize the resistance to the fluid in the sheath flow back pool and minimize the dead corner where bubbles can hide, thereby avoiding bubbles adhering to or being stored at the back pool electrode to affect the cleaning ability of the sheath flow back pool. The front pool flushing liquid and the back pool flushing liquid can be diluted sheath liquid, and after each detection is completed, the counting hole 300 is flushed to ensure the accuracy of the next detection.

[0047] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. The scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A sheath flow electrical impedance particle counting device, comprising a sheath flow forecell and a sheath flow aftercell, wherein the sheath flow forecell and the sheath flow aftercell are connected through a counting hole to form a particle passage, characterized in that: The sheath flow fore cell is provided with a fore cell electrode, a sample needle, a sheath liquid inlet and a fore cell flushing inlet, and the sample needle is used to transport the sample liquid into the sheath flow fore cell; the sheath flow back cell is provided with a back cell electrode, a back cell flushing inlet and a back cell flushing outlet; the fore cell electrode and the back cell electrode jointly form a current loop for particle detection; the fore cell flushing inlet and the back cell flushing inlet are both facing the counting hole, and the back cell flushing inlet is located below the X horizontal plane passing through the central axis of the counting hole, the back cell electrode is a solid cylindrical structure or a hollow cylindrical structure, and the central axis of the back cell electrode is parallel to the central axis passing through the counting hole, or the back cell electrode is coaxially arranged with the counting hole.

2. The sheath flow impedance particle counting device according to claim 1, wherein: The rear cell electrode is a corrosion-resistant structure, or a corrosion-resistant layer is provided on the surface of the rear cell electrode.

3. The sheath flow impedance particle counting device according to claim 2, wherein: The rear cell electrode is a hollow cylindrical structure, the rear cell electrode is coaxially arranged with the counting hole, and the rear cell electrode serves as a sample waste liquid collection tube.

4. The sheath flow impedance particle counting device according to claim 2, wherein: The rear cell electrode is a solid cylindrical structure. A sample waste liquid collection tube is further provided on the sheath flow rear cell, and the tube mouth of the sample waste liquid collection tube faces the counting hole.

5. The sheath flow impedance particle counting device according to claim 4, wherein: The rear cell electrode is spaced apart from the sample waste liquid collection tube, and the central axis of the rear cell electrode is parallel to the central axis of the sample waste liquid collection tube.

6. The sheath flow impedance particle counting device according to claim 5, wherein: The rear pool flushing inlet is located below the sample waste liquid collection tube, and the outer periphery of the rear pool electrode and the outer periphery of the sample waste liquid collection tube do not overlap in a direction perpendicular to the X horizontal plane.

7. The sheath flow impedance particle counting device according to claim 6, wherein: The distance between the central axis of the rear cell electrode and the central axis of the sample waste liquid collection tube in a direction parallel to the X horizontal plane is greater than the sum of the radius of the rear cell electrode and the radius of the sample waste liquid collection tube.

8. The sheath flow electrical impedance particle counting device according to any one of claims 1 to 7, wherein: The rear pool flushing inlet and the rear pool flushing outlet are located in the same vertical plane; or, the central axis of the rear pool flushing inlet is set at a preset angle to the X horizontal plane, and the central axis of the rear pool flushing outlet is perpendicular to the X horizontal plane.

9. The sheath flow electrical impedance particle counting device according to any one of claims 1 to 7, wherein: The front pool flushing inlet and the sheath fluid inlet are located in the same vertical plane; or, the central axis of the front pool flushing inlet is set at a preset angle to the X horizontal plane, and the central axis of the sheath fluid inlet is perpendicular to the X horizontal plane.

10. The sheath flow electrical impedance particle counting device according to any one of claims 1 to 7, characterized in that: The front pool flushing inlet and the rear pool flushing inlet are symmetrically arranged relative to a vertical plane perpendicular to the central axis of the counting hole, and / or the sheath fluid inlet and the rear pool flushing outlet are symmetrically arranged relative to a vertical plane perpendicular to the central axis of the counting hole.

11. The sheath flow electrical impedance particle counting device according to any one of claims 1 to 7, characterized in that: The portion of the sheath flow front pool close to the counting hole is tapered, and / or the portion of the sheath flow rear pool close to the counting hole is tapered.

12. A detection method, applied to the sheath flow electrical impedance particle counting device according to any one of claims 1 to 11, characterized in that: The detection method comprises the following steps: delivering the sample liquid into the sheath flow forecell through the sample needle; The sheath liquid is fed into the sheath flow forecell through the sheath liquid inlet, and the sheath liquid wraps around the particles in the sample liquid so that the particles pass through the counting hole one by one and generate an electrical signal; The number and volume information of sample particles are obtained by counting and analyzing the electrical signals.

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