RU1810796C - Device for measurement of concentration of microparticles - Google Patents

Abstract

Usage: medicine, biologists, etc. Summary of the invention: a second threshold discriminator, anti-coincidence circuit, integrator, comparator, signaling device, first and second voltage dividers with corresponding connections are additionally introduced into the device. 2 ill.

Description

The invention relates to measuring technique, is intended for the determination of small concentration particles (microparticles) in suspensions, and can be used in medicine, biology, and other fields of science and technology.

The purpose of the invention is to improve the operational characteristics of the device by signaling the departure of the discriminator's operating point.

In FIG. 1 shows a block diagram of a device; in FIG. 2 is a graph illustrating his work.

The device contains a hydraulic system 1, a conductometric pulse sensor 2, a pulse amplifier 3, a first threshold discriminator 4, one input of which is connected to a voltage source Unop, and the other is connected to the output of an amplifier 3, pulse counter 5, switched on and off by hydraulic system 1, a second threshold discriminator 6, anti-coincidence circuit 7, integrator 8, comparator 9, signaling device 10, first 11 and second 12 voltage dividers, while the first input of the second discriminator 6 is connected to the output of the pulse amplifier 3, the input of the first divider voltage 11 is connected to the first input of the first discriminator 4, and the output of the first divider 11 is connected to the second input of the second discriminator 6. The output of the second discriminator 6 is connected to the second input of the anti-coincidence circuit 7, the first input of which is connected to the output of the first discriminator 4. The output of the anti-coincidence circuit 7 connected to the input of the integrator 8, the discharge input of which is connected to the hydraulic system 1, and the output to the first input of the comparator 9. The second input of the comparator 9 is connected to the output of the second voltage divider 12, the input of which is connected to the source DC voltage Un. The output of the comparator 9 is connected to the input of the detector 10.

The operation of the device is as follows.

Under the influence of the vacuum created by the hydraulic system 1, a suspension of the test particles is sucked through the micro-holes of the conductometric pulse sensor 2. Moreover, it seemed

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Yes, the particle generates an electric voltage pulse at the output of the sensor, the amplitude of which is proportional to the size (volume) of the particle. These pulses are amplified by amplifier 3, formed by discriminator 4, and fed to the input of counter 5. The counter is turned on and off by hydraulic system 1 so that pulses from particles contained in the dose of suspension D are counted. Discriminator A is set so that only the particles under study are counted and not smaller particles were considered. In this case, the operating point of the discriminator DI is approximately in the middle of the plateau of the integral distribution curve of the amplitudes of the pulses from the particles passing through the micro-hole. In this case, NI particles will be counted. The falling section of the curve to the right of the plateau corresponds to the counted particles. The rising portion of the curve to the left of the plateau corresponds to dirt particles and electronic noise. The accuracy depends on the relative position of the operating point of the discriminator, the distribution curve for the size of the test particles and the distribution curve for the size of the particles of dirt. If the operating point of the discriminator is within a plateau, the counting results when the working point is shifted do not change significantly.

If the operating point of the discriminator shifts to the right beyond the plateau, the counting results will be underestimated. The reasons for shifting the operating point to the right may be a decrease in the size of the read particles, an increase in the temperature of the suspension, and a malfunction of the power source.

If the operating point of the discriminator shifts beyond the plateau to the left, for example at position D2, the counting results will be overestimated. The reasons for the shift of the operating point to the left can be an increase in the size of dirt particles, a decrease in the temperature of the suspension, an increase in the level of electronic noise, and a malfunction of the power supply.

Changing the position of the discriminator's operating point relative to the plateau in analogs remains unnoticed by the operator, which distorts the counting results.

In this device, this drawback is eliminated as follows. The threshold of the second discriminator 6 with the help of the voltage divider 11 is set below the threshold of the first discriminator 4 by the value of D U. In this case, the threshold discriminators 4 and 6 together with the anti-coincidence circuit 7 form a gap discriminator, which allows

only pulses from particles whose sizes correspond to the width of the gap. These pulses are converted, by integrator 8, into a constant voltage, which is applied

to one of the inputs of the comparator 9. A constant voltage from the voltage divider 12 is applied to the other input of the comparator. If the voltage at the output of the integrator 8 exceeds the voltage set by the divider 12, the comparator operates by turning on the indicator 10. At the beginning of each new counting cycle the hydraulic system 1 resets the integrator 8, and the indicator 10 is turned off as well. Voltage divider 12

sets the sensitivity of the device for a given slot width set by the voltage divider 11.

If there are few 7 pulses at the output of the anti-coincidence circuit, then the voltage at the first

the input of the comparator 9 is less than the voltage at the second input and the indicator does not turn on.

If the number of pulses at the output of the anti-coincidence circuit 7 increases, then the voltage at the first input of the comparator 9 exceeds the voltage at the second input, as a result of which the signaling device is triggered. In the same way, you can illustrate the operation of the device by shifting the discriminator's operating point to the left.

Claims (1)

The claims g A device for measuring the concentration of microparticles containing a hydraulic system, serially connected conductometric pulse sensor, a pulse amplifier, a threshold discriminator and a pulse counter, controlled a hydraulic system, characterized in that, in order to improve the operational characteristics of the device by signaling that the operating point of the discriminator has gone off, a second threshold discriminator, an anti-coincidence circuit, an integrator are introduced into it; comparator, signaling device, first and second voltage dividers, the first the input of the second discriminator is connected to 1 by the output of a pulse amplifier, the input of the first voltage divider is connected to the first input of the first discriminator, and the output of the first divider is connected to the second input of the second discriminator, the output of which is connected to the second input of the anti-coincidence circuit. the first input of which is connected to the output of the first discriminator, and the output of the anti-coincidence circuit is connected to the input of the integrator, the reset input of which is connected to the hydraulic system, and the output is to the first input of the comparator, the second input of which is connected to the output of the second voltage divider, the input of which is connected to a constant voltage source, the output of the comparator is connected to a signaling device. gioyoilkho A 4. .. 2  f.