JPH0120676Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a particle counting method in which particles such as blood cells suspended in a liquid are passed through micropores and detected based on the difference in electrical impedance between the liquid and the particles. This relates to the detector of the device, and uses a metal pipe with a small inner diameter as the sample suction pipe of the detector, which also serves as the internal electrode, to prevent detection failures due to electrolytic corrosion, etc. It is an object of the present invention to provide a detector which is suitable for effectively detecting particles of different sizes and whose overall thickness can be reduced.

[Conventional technology]

Traditionally, when counting particles such as blood cells, particles such as blood cells suspended in a liquid are passed through micropores, detected based on the difference in electrical impedance between the liquid and the particles, and converted into an electrical pulse signal. A particle counting device is used that counts pulse signals corresponding to particles.

[Problem that the invention attempts to solve]

In this particle counting device, there has been a phenomenon in which an unnecessary pulse signal is generated due to the entrainment of the previous sample, the sample before the previous sample, or the current sample that has already been aspirated on the back side of the fine hole. In particular, this phenomenon
A mixture of large and small particles gets caught up in the detection area near the micropore, and the pulse from the larger particle generates a pulse similar to when a small particle passes through the micropore, e.g., red blood cells and platelets. This method has the disadvantage that large and small particles such as these are forced to pass through the micropores at the same time, resulting in large errors when performing classification and counting due to the difference in the size of the output pulse.

In order to prevent the above phenomenon, there is a method to create a double structure on the back side of the fine pores of the detector to suck out all the particles that have passed through the fine pores, or to replace the flow of liquid containing particles with liquid that does not contain particles. One possible method is to wrap the liquid and pass it through micropores to create a structure that does not cause the entrainment phenomenon, but this has the disadvantage that the structure becomes extremely complicated and it becomes impossible to quantify the sucked liquid. In addition, we coated the inside with metal to reduce the detection area,
There are methods such as vapor deposition or plating, but these methods have the drawback of peeling off due to electrolytic action or the like, or the surface becoming frayed, making them impractical.

The present invention was developed in view of the above points, and an object of the present invention is to provide a detector for a particle counting device that has a simple structure and is capable of accurate detection.

[Means for solving problems]

The detector of the particle counting device of the present invention has a small detector pellet 4 having a fine hole 3 placed at the tip of a metal pipe 1 having a small inner diameter, the tip of which is sealed and a fine hole 2 is bored in the sealed portion. The holes are brought into contact and fixed so that they communicate with each other, and the outer peripheries of the metal pipe and detector pellet are covered with an electrical insulator 5. On the other hand, a bulge is provided at the other end of the metal pipe 1 for taking out the electrode and for fixing it. A detector main body upper part 10 is provided with an integrally extending protrusion 6 and has a narrow liquid passage 8 in the longitudinal center thereof.
The liquid passage of this bulge 6 and the upper part of the detector body 1
The metal pipe 1 is fixed so as to be in communication with the liquid passage 8 of No. 0, and the liquid passage 8 is further connected to a suction pressure source, so that the metal pipe 1 serves as a sample suction pipe and an internal electrode.

[Effect]

When a suction pressure is applied to the liquid passageway 8, the particle suspension is sucked through the fine pores 3 of the detector pellet 4. Since the metal pipe 1, which serves as the sample suction pipe and internal electrode, is located adjacent to the detector pellet 4, the detection area is extremely small, and if particles enter the metal pipe side when passing through the micropores, they will no longer be detected. After leaving the region, no output pulse is generated. Therefore, unnecessary pulses due to particle entrainment phenomena are no longer generated.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings. 1 is a thin metal pipe made of a corrosion-resistant metal such as stainless steel and has an inner diameter of about 0.5 to 1 mm; the tip of the metal pipe 1 is sealed, and a microhole 2 is drilled in the sealed part. There is. A detector pellet 4 having a fine hole 3 with a diameter of about 60 to 100 microns at the tip of the metal pipe 1 has a fine hole 2,
The three comrades are brought into contact and fixed so that they communicate with each other. The fine hole 2 at the tip of the metal pipe 1 has a tapered shape that is equal to or somewhat larger in diameter than the fine hole 3 of the detector pellet. The outside of the metal pipe 1 and the outside of the detector pellet 4 are coated with an electrical insulator 5 such as synthetic resin or glass for electrical insulation.
A bulge 6 is formed at the top of the metal pipe 1 for taking out and fixing the electrode. This bulge 6
is also covered with an electrical insulator 5. As mentioned above, the metal pipe 1 is a thin pipe with an inner diameter of about 0.5 to 1 mm, so that the aspirated sample is quickly removed and it also serves as an internal electrode. This metal pipe 1, which also serves as an internal electrode, is electrically taken out to the outside via a terminal 7 provided on the upper bulge 6. On the other hand, the upper end of the metal pipe 1 is connected to the upper part 10 of the detector body, which has a narrow liquid passage 8 in the center.
The upper end of the metal pipe 1 and a liquid passage 8 are fixed so as to communicate with each other, and the liquid passage 8 is further connected to a suction pressure source by the following structure. That is, the detector main body upper part 10 has two liquid reservoir spaces 12 and 13 (the lower space is 12 and the upper space is 13) that are vertically adjacent to each other with a flexible diaphragm 11 interposed therebetween. However, the lower space 12 communicates with the liquid passage 8. This lower space 12 is connected to a drainage reservoir and a suction pressure source via a passage 14, a solenoid valve 15, etc.
On the other hand, the upper space 13 is connected via a passage 16 to a liquid metering device. The upper part of the detector body 1
0 is made of synthetic resin such as polyacetal. Although FIG. 1 shows a case where the upper end of the metal pipe 1 and the upper part of the detector main body 10 are fixed with screws, it is also possible to adopt other methods, such as a method of tightly fitting them. It is.
In this way, the detector of the present invention has a detector pellet 4
Since the internal electrode and sample distribution pipe is located directly behind the sensor, the detection area is extremely small, and the influence of so-called entrainment on small particles is extremely prevented. Note that it is desirable to use thick-walled metal pipes to protect against corrosion and electrolytic corrosion.

Next, an example of a particle counting device equipped with the detector of the present invention configured as described above will be explained based on FIG. 3. 17 is a passage 14 in the space below the detector.
The liquid transfer control device 17 is further connected to the sample inlet 20 and sample outlet 21 of the sample container 18 to transfer the particle suspension 22 and the detector. This is a device for controlling the suction and discharge of samples from inside. Reference numeral 23 denotes a liquid quantitative device connected to the space above the detector via a passage 16, and is a device for quantifying the particle suspension sucked through the fine hole at the lower end of the detector. 24 is a detection circuit connected to the internal electrode and the external electrode 25;
4 is connected to an upper level threshold circuit 26 to pass pulses due to larger particles. The detection circuit 24 also includes an upper level threshold circuit 2.
A delay circuit 27 is connected to synchronize with the inhibition signal No. 6, and when the particle signal of the upper level threshold circuit 26 is reached, the passage of the pulse is blocked by inactivating the next low level threshold circuit 28. . At the same time, it blocks small signals such as noise from passing through. 30 is a counting circuit for signals passing through the upper level; 31 is a counting circuit for low level signals; 3
2 is a display circuit that displays the counting results of large particles;
33 is a display circuit for displaying the counting results of small particles.

In order to detect particles in a particle suspension using the particle counting device configured as described above, a suction pressure is applied to the upper space 13 and the inside of the detector is brought into suction pressure through the diaphragm 11. A particle suspension is sucked through the fine holes 3 of the detector pellet 4, and is quantified by the liquid metering device 23, and a start/stop signal is generated to start and stop counting. After measurement, suction pressure is applied to the lower space 12 to return the diaphragm 11 and at the same time discharge the liquid inside the detector to the outside.

[Effect of idea]

As explained above, in the detector of the present invention, as shown in Fig. 2, the metal pipe is located immediately behind and adjacent to the detector pellet, so the detection area is extremely small, and particles pass through the fine holes. If it enters the metal pipe side when doing so, it will no longer be in the detection area and no output pulse will be generated. Therefore, unnecessary pulses due to particle entrainment phenomena are no longer generated. In addition, since the metal pipe also serves as an internal electrode, the electrode surface area is large and the electrode can be brought close to the micropores as described above, without causing detection failures due to noise or electrolytic corrosion.
Because the inner diameter is small, the previous sample is quickly discharged.
This has the effect of allowing accurate detection and measurement.

Furthermore, a metal pipe 1 and a detector pellet 4
Since the outer periphery of the detector is covered with the electrical insulator 5, the thickness of the entire detector can be made thinner.
Therefore, the amount of particle suspension that adheres around the detector is also reduced, and when measuring different samples one after another, the extent to which the previous sample adheres around the detector and contaminates the next sample is reduced. It becomes less. Furthermore, even if the area around the detector is cleaned every time, the thinner the detector is, the less cleaning liquid will be consumed.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional explanatory diagram showing one embodiment of the detector of the particle counting device of the present invention, Figure 2 is an enlarged view of the lower end of the detector shown in Figure 1, and Figure 3 is the detection of the present invention. FIG. 2 is a systematic explanatory diagram showing an example of a particle counting device equipped with a particle counting device. 1... Metal pipe, 2, 3... Fine hole, 4...
...Detector pellet, 5...Electric insulator, 6...Bulge, 7...Terminal, 8...Liquid passage, 10...Detector main body upper part, 11...Diaphragm, 12,1
3... Space, 14... Passage, 15... Solenoid valve, 1
6... passage, 17... liquid transfer control device, 18...
... Sample container, 20 ... Sample inlet, 21 ... Sample outlet, 22 ... Particle suspension, 23 ... Liquid quantitative device, 24 ... Detection circuit, 25 ... External electrode, 26
... Threshold circuit, 27 ... Delay circuit, 28 ... Threshold circuit, 30, 31 ... Counting circuit, 32, 33 ...
display circuit.

Claims (1)

[Scope of utility model registration request] A detector pellet 4 having a fine hole 3 is brought into contact with and fixed to the tip of a metal pipe 1 having a small inner diameter, the tip of which is sealed and a fine hole 2 is bored in the sealed portion so that the fine holes communicate with each other. The outer periphery of the metal pipe and the detector pellet is covered with an electrical insulator 5, while a bulge 6 for taking out and fixing the electrode is integrally provided at the other end of the metal pipe 1. The part is fixed to the upper part 10 of the detector body having a narrow liquid passage 8 in the longitudinal center thereof so that the liquid passage of this bulged part 6 and the liquid passage 8 of the upper part 10 of the detector body communicate with each other, and furthermore, the liquid A detector for a particle counting device characterized in that a passage 8 is connected to a suction pressure source and a metal pipe 1 serves as a sample suction pipe and an internal electrode.