JPS6199839A - Particle detector - Google Patents

Abstract

PURPOSE:To prevent particles which has flowed in from returning to the periphery of a fine hole by inserting the 2nd pipe into the 1st pipe which has the fine hole, forming a small hole in the side wall of the 2nd pipe at the back surface side about the fine hole, and flowing particles in the pipe and sucking them. CONSTITUTION:Liquid which contains red blood cells and blood platelets to be detected is put in a container 20. A detection pipe 21 consists of pipes 21 and 22. The pipe 22 has an electrode 24 internally, and held at the upper part of the electrode 24 and dipped in the liquid in the container 20. The fine hole 27 is formed in the side wall of the pipe 22 and liquid containing no particle is put in the pipe 22 previously. A pipe 23 consists of a cylindrical electrode 29 and a pipe 30 which is fitted to the lower end of the electrode 29 and closed at the lower end. The pipe 23 is also held in the pipe 22 in the center and the pipe 30 has a small hole 31 in the side wall at the back surface side about the fine 31 in the side wall at the back surface side about the fine hole 27. The electrodes 24 and 29 are connected to a detecting circuit 32 and the liquid in the pipe 23 is sucked by a sucking means 33. Consequently, particles passed through the fine hole 27 as a detection area are prevented from returning the periphery of the fine hole again, thereby improving precision.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a particle detection device for detecting particles suspended in a liquid. The present invention relates to a particle detection device that detects particles by type from a liquid containing a mixture of particles.

[Prior art and problems to be solved by the present invention] Conventionally, when detecting particles floating in a liquid, an apparatus as shown in FIG. 11 has been used. To explain this figure, a container 1 contains a liquid in which particles to be detected are suspended. A tube 3 having micropores 2 is provided within the container 1, and is positioned such that the portion including the micropores 2 is immersed in the liquid within the container 1. The tube 3 contains a particle-free liquid. II to the liquid in container 1
The i-electrode 4 is immersed, and the electrode 5 is immersed in the liquid in the tube 3. A predetermined current is caused to flow between these electrodes 4 and 5 by a detection circuit 6. When the liquid in the tube 3 is sucked in the direction of arrow A in this state, the liquid in the container 1 flows into the tube 3 through the micropores 2. and micropore 2
When particles pass through the micropores 2, the impedance inside the micropores 2 increases.

The detection circuit 6 extracts this change in impedance as a change in current, and outputs a pulse corresponding to this change. The number of pulses indicates the number of particles passing through the micropores 2, and the peak value of the two pulses indicates the size and volume of the particles passing through the micropores 2. Therefore, when counting multiple types of particles with different sizes, such as red blood cells and platelets, for example, a threshold value is set at the peak value of the pulse, and each particle type is determined based on this threshold value. All you have to do is decide. However, when this method is adopted to count the number of particles by type, the following drawbacks arise.

First, there is no problem if the detection area for detecting particles is only inside the micropore 2, as shown by the equipotential lines in Figure 12, but in reality, it is around the entrance and exit of the micropore 2, as shown in Figure 13. There is also a detection area. The liquid that has entered the tube 3 is flowing as shown in FIGS. 14 and 15. That is, the particles Fi that once passed through the micropores 2 return to the vicinity of the exit of the micropores 2. Therefore, for example, when detecting two types of particles with different volumes, when the particle with the larger volume returns to the vicinity of the exit of the micropore 2, the detection circuit 6Fi will respond to the particle with the larger volume. An IR pulse with a peak value lower than the peak value may be generated. If the pulse height value of this pulse is higher than the pulse height value of the particle with the smaller volume, it means that the particle with the smaller volume has been detected.

For this purpose, particles are detected using the apparatus shown in FIG.
If you count the particles, the particles with smaller volume will be counted more than the actual number.

For example, when the two types of particles to be detected are red blood cells and platelets, errors occur in counting platelets with a small volume.

In order to prevent such errors from occurring, it is necessary to prevent particles that have once flowed into the tube 3 from the micropores 2 from returning to the vicinity of the micropores 2. Conventionally, a tube 11 having a pore 10 is inserted into the tube 3 as shown in FIG. was inhaling. 17 is a cross-sectional view of the device shown in FIG. 16 in the X-X direction.
As shown in the figure. In this way, the liquid flowing in through the fine holes 2 is immediately sucked into the tube 11 through the fine holes 10.

In this device, the liquid flowing from the micropores 2 flows into the tube 11.
However, this structure has a region R shown in FIG. 17 where the liquid does not move (referred to as a water stop region), so when the liquid flows into this region, a shear flow occurs. Moreover, at this time, since the liquid is accelerated in the micropores 2, a pressure drop occurs, and the pressure is lower than the pressure Po in the water stop region. Therefore, the liquid that has flowed in from the micropores 2 flows into the direction where the pressure is lower, producing a flow C shown in the figure. In other words, this flow becomes a flow returning to the micropores 2.

To prevent this, it is necessary to lower the pressure near micropore 2 to
The pressure P2 near 0 must be reduced. For this purpose, the velocity v2 in the pore 10 must be made larger than the velocity Vl in the a micropore 2. by the way,
Due to the structure, the amount of liquid flowing in from the micropores 2 and the amount of liquid passing through the micropores 10 must be equal (If the cross-sectional area of the micropores 2 is AI and the cross-sectional area of the micropores 10 is AI, then AI V
l ==A2y2), the cross-sectional area h must be smaller than the cross-sectional area A1.

However, before diffusion occurs, the jet from the micropore 2 with a cross-sectional area ^ is transferred to the micropore 1 with a cross-sectional area A2 smaller than the cross-sectional area AI.
It is technically difficult to suction everything from zero, and if the cross-sectional area N is made even smaller than the cross-sectional area AI of the fine pores 2, the fine pores 10 will become extremely small, causing the problem of clogging. On the other hand, there is also a method in which a porous material is filled in a tube having micropores, and the liquid flowing from the micropores is sucked through the porous material. According to this method, the liquid flowing in through the micropores does not directly collide with the wall inside the pipe, but it cannot be denied that particles remain in the porous material around the micropores, so the particles return to the vicinity of the micropores. A phenomenon similar to that occurs. Another method that can be considered is to cause the jet from the micropores to collide with the inner wall of the pipe at a predetermined angle to cause a deflection of the flow. , particles that return to the vicinity of the micropores do not decrease.

The present invention was made in view of the above-mentioned drawbacks, and its purpose is to detect particles in which particles flowing through the micropores, which are the detection area for detecting particles, do not return to the vicinity of the micropores.
The goal is to provide a variety of benefits.

[Structure of the invention]

Therefore, in the present invention, a second tube is inserted into a first tube having micropores, and a micropore is provided on the wall of the second tube that is the back side of the micropore. The above object is achieved by allowing liquid to flow into the second tube through the hole and suctioning the liquid.

[Effect]

In this way, the liquid that has flowed into the first tube from the micropores is separated into two directions, passes through the gap between the inner wall of the first tube and the outer wall of the second tube, and then separates the liquid from the second tube. They meet at a position opposite to the fine pores, flow into the pores from there, reach the second tube, and are sucked.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram for explaining the entire apparatus of the present invention. In the figure, 20 is a container. This container 20 contains a liquid containing red blood cells and platelets to be detected. 21
is a detection tube. The detection tube 21 includes a first tube n and this first tube n.
and a second tube n inserted into the tube 22 of the second tube n. A perspective view of this detection tube 21 is shown in FIG. The first tube n contains therein an electrode scrap having the shape shown in FIG. 3, and is made of plastic molding. The middle part 24a of the electrode scrap has a cylindrical shape, and the upper part 24b has a thick ring shape.

The reason why the electrode waste was shaped like this was because the first tube was sealed.
This is to do so. Furthermore, the lower part 24c of the electrode 24 is a U-shaped member so that a portion thereof is exposed from the bottom surface of the first tube 22, and is made of a material with excellent corrosion resistance (for example, platinum). A notch 25 is formed on the side wall of the first tube 22.
is provided to form a plane parallel to the axial direction. A hole is bored in the notch 5. This hole 26 has a tapered shape that becomes narrower toward the inside until the middle thereof. A disc-shaped member portion having a fine hole 27 is fitted inside the tapered portion of this hole 26. The outside and inside of the first tube 22 communicate with each other through the micropores 27 . The disc-shaped member 28 is made of ruby or sapphire. The first tube 22 configured in this manner is immersed in the liquid in the container 20 by holding the upper portion 24b of the electrode 24 by a holding portion (not shown).

This first tube 22 contains a particle-free liquid in advance. The second tube consists of a cylindrical electrode 29 and a tube 30 attached to the lower end of the electrode 29 by fitting its upper portion. The lower end of tube I is closed.

This second tube 23 is also held at the center inside the first tube 22 by a holding section (not shown).

The tube 30 has a pore 31 on the side wall on the back side with respect to the pore 27 .

The second tube is shown in a perspective view as shown in FIG. 4.

This is a 32rri detection circuit. The detection circuit 32 is connected to the electrode scrap and the electrode 29, and outputs a pulse having a peak value corresponding to a change in impedance between the two. 33
is a suction means. The suction means 33Fi is for suctioning the liquid inside the second tube.

In the apparatus of this embodiment configured as described above, first, when the liquid in the second tube 23 is sucked in the direction of the arrow by the suction means 33, the liquid in the container 20 is transferred to the detection tube 2 in FIG.
As shown in the cross-sectional view of No. 1, it flows into the inside of the first pipe n through the micropores 27. This flow then passes through the second pipe 23 (pipe 30
), and the respective flows flow along the side wall of the second tube 23 (tube 30) and merge around the pore 31. When these two flows merge, each flow collides head-on, so the velocity rapidly decreases and stagnation occurs. In addition, generally when a cylindrical member is placed perpendicular to the flow, a boundary layer is generated on its surface, but in the case of this device, a boundary layer is similarly generated on the surface of the tube 30, which promotes a decrease in the speed of the flow. . Since the position where the stagnation occurs is around the entrance of the pore 31, this stagnation is sucked out from the pore 31. In this way, from the micropore 27 to the micropore 3
A constant flow occurs up to 1.

In this state, the detection circuit 32 outputs a pulse having a peak value corresponding to the size of each red blood cell or platelet passing through the micropore 27.

In this way, according to the device of the present example, the liquid that has passed through the micropores 27 will not pass near the micropores 27 again. Therefore, red blood cells or platelets contained in such liquid will not return to the vicinity of the micropores 27. Therefore, the Noculus peak value output from the detection circuit 32 is
This will accurately indicate the size of each red blood cell or platelet that has passed through Step 7.

In the above embodiment, there is a tube for introducing liquid into the second pipe 23.
The fine holes 31 are the fine holes 27 provided in the first tube 22.
On the other hand, it is provided on the side wall on the back side at a position opposite to the fine hole 27 (Z). In this case, as described above, a boundary layer is generated along the side wall of the second tube, that is, along the side wall surface of the tube 30, but when the flow velocity is high, the boundary layer is formed along the side wall surface of the tube 30, as shown in FIG. Peel it off. The separated boundary layer then becomes a large vortex or splits into many smaller vortices.

If these vortices are generated before reaching the vicinity of the pore 31,
Since the stagnation area will expand, the particles will become micropores 2.
There is a possibility that it will return to around 7. Therefore, the tube 30 shown in FIG. 7 is used.

This tube 30A has three pores. One of the pores 34 is located at a similar location to the tube 30 of the embodiment described above. The other two pores 35° and 36 are the two points (separation points) where boundary layer separation occurs as shown in Figure 6.
It is set in. If such a pipe 30A is used, the separation point will occur downstream of that shown in FIG. Therefore, if the pores 35 and 36 are provided at positions corresponding to the flow velocity, a vortex generated by separation of the boundary layer can be generated near the pore M. As a result, the stagnation area is reduced, and particles that have flowed into the first tube are further prevented from returning to the vicinity of the micropores.

Here, an experiment conducted to compare the effects of the device according to the present invention and the conventional device will be described. This experiment was conducted using ink instead of the liquid containing red blood cells and platelets, and using the actual equipment for each. In this way, the flow of the liquid is visualized, so the person conducting the experiment can directly grasp the experimental results.

First, a device corresponding to the conventional device will be described. As shown in FIG. 8, a transparent liquid is contained in a container 40 made of a transparent material, and ink can be injected from the side wall of the container 40 with a syringe 41. Let's do it like this.

Then, a part of the tube 43 having the hole 42 is immersed in the liquid contained in the container 40. The tube 43 is also made of a transparent material. The lower end of this tube 43 is closed, so that the liquid in the container 40 can flow into the tube 43 only through the hole 42. A tube material is inserted into the tube 43. In this state, when ink is injected from the syringe 41 while sucking the liquid in the tube 43 through the tube 44, the ink flowing into the tube 43 flows in the direction of the arrow shown in FIG. 9(a) and Φ). , and a stagnation E occurred near the hole 42.

Next, regarding a device corresponding to the device of the present invention, this device is the device shown in FIG. 8, in which the upper part of the tube 45 is fitted to the tip of the tube material. The lower end of tube 45 is closed. This tube 45 has a hole provided in its side wall. This hole 46 is located on the side wall of the tube 45 on the back side with respect to the hole 42. In this state, if ink is injected from the syringe 41 while sucking the liquid inside the tube 44, the hole 42
The ink that has reached the inside of the tube 43 flows in the direction of the arrow shown in FIGS. 10(a) and 10(b). Ink stagnation did not occur near the FFi holes 4 and 6 or near the hole 42.

〔Effect of the invention〕

As described above, according to the present invention, particles that have once passed through the micropores that are the detection area do not return to the vicinity of the micropores, so that particles can be detected accurately. Therefore, if a plurality of types of particles are counted by type using the apparatus of the present invention, it is possible to prevent returning particles with a large volume from being mistakenly counted as particles with a small volume, and the accuracy of the counted value is improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the entire apparatus of the present invention, Fig. 2 is a perspective view of the detection tube shown in Fig. 1, and Fig. 3 shows the electrode embedded in the first tube of the detection tube. 4 is a perspective view showing the second tube of the detection tube, FIG. 5 is a sectional view of the detection tube, and FIG. 6 is a surface of the second tube having one pore. FIG. 7 is an explanatory diagram showing the flow of liquid on the surface of the second tube having a plurality of pores, and FIG. 8 is an explanatory diagram showing the flow of liquid on the surface of the second pipe having a plurality of pores. A configuration diagram of an experimental device corresponding to the conventional device used in the experiment, FIG. 9 is an explanatory diagram showing the effect of the experimental device similarly corresponding to the conventional device, and FIG. 10 similarly corresponds to the device of the present invention. FIG. 11 is an explanatory diagram showing the effects of the experimental device, and FIG. 12 is a configuration diagram of a conventional device. FIG. 13 is an explanatory diagram showing the detection area for detecting particles,
FIG. 4A and FIG. 17 are cross-sectional views of a detection tube for explaining the flow of liquid in a conventional device. 20... Container 21... Detection tube 22... First tube 23... Second tube 24.29... Electrode n...
- Micropore 31... Pore 32... - Detection circuit 33.
... Attraction means agent Patent attorney Book 1) Takashi Figure 8 Figure 11 Figure 12 Figure 13

Claims (2)

[Claims] (1) A container containing a particle-suspended liquid in which particles to be detected are suspended, and a particle-free container that has micropores in its side wall and is provided so that its interior communicates with the interior of the container only through the micropores. a first tube containing a liquid; a second tube inserted into the first tube and having a fine hole bored in a side wall on the back side with respect to the fine hole; A suction means for suctioning the inflowing liquid, two electrodes immersed in the liquid on the inside and outside of the side wall of the first tube, and detecting an electric signal according to a change in impedance between the two electrodes. 1. A particle detection device comprising a detection circuit. (2) The second tube has a plurality of pores formed in a side wall on the back side of the pores and on a plane including the pores. The particle detection device according to scope 1.