JP2011257263A - Granularity distribution measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granularity distribution measurement device that calculates a granularity distribution of a group of particles to be measured included in a body to be measured by using a light intensity distribution of suitable intensities.SOLUTION: The granularity distribution measurement device 1 includes a light source 11 which emits measurement light, a detector 14 which has a plurality of optical detection elements for detecting light intensities and detects the light intensity distribution by the plurality of optical detection elements, and a granularity distribution calculation unit 43 which calculates the granularity distribution of the group of particles to be measured included in the body to be measured using a light intensity distribution acquired by a light intensity distribution acquisition unit 41, and the light intensity distribution acquisition unit 41 detects the light intensities detected by the respective optical detection elements so as to integrate them respectively, and determines to end the integration of the light intensities detected by the respective optical detection elements based upon a light intensity integrated by at least one optical detection element.

Description

  The present invention relates to a particle size distribution measuring apparatus that measures the particle size distribution of a group of particles to be measured included in a measured object using an optical method (for example, laser diffraction / scattering method).

  In a laser diffraction / scattering type particle size distribution measuring device, a group of particles to be measured (for example, powder) in a dispersed state is irradiated with laser light (measurement light) in a medium (for example, water or air). The spatial light intensity distribution of the laser light diffracted and scattered by the group of particles to be measured is detected by a plurality of light detection elements, and the calculation based on the Fraunhofer diffraction theory and Mie scattering theory is performed from the light intensity distribution. Thus, the particle size distribution of the particle group to be measured is calculated.

FIG. 4 is a diagram illustrating an example of a schematic configuration of a conventional particle size distribution measuring apparatus. In FIG. 4, a schematic diagram showing a configuration of the optical system and a block diagram showing a configuration of a signal processing system including a data sampling circuit and a computer are shown together.
The particle size distribution measuring apparatus 101 includes a measurement space arranging unit 13 for arranging a measurement space, an irradiation optical system 12 for irradiating the measurement space with laser light, a detection optical system 14 for detecting a light intensity distribution, and measurement. A sample supply device 2 for supplying an aerosol (object to be measured) S to the space, a data sampling circuit 15, a communication control circuit 16, and a computer (control unit) 117 for controlling the entire particle size distribution measurement device 101 are provided.
Here, the particle size distribution of the measured particle group P is calculated by measuring the aerosol S in which the measured particle group P is dispersed in the air (medium) L.

The measurement space disposition unit 13 has a lower connection port at the lower end and an upper connection port at the upper end. And the lower side connection port of the measurement space arrangement | positioning part 13 is connected with the sample supply apparatus 2 via the aerosol transfer pipe 24f. The upper connection port is connected to the pump 34 via the suction pipe 31.
In such a configuration, when the pump 34 is driven, the aerosol S in the sample supply mechanism 2 flows into the measurement space from the lower connection port, and passes through the measurement space from the lower side to the upper side. It flows out from the connection port.

The sample supply device 2 includes a base 25 having a rotating shaft 21a in the vertical direction, a disk-shaped turntable 21, a hopper 22, a filler 23, and a transfer mechanism 24 disposed above the turntable 21. Is done.
The turntable 21 can rotate in a direction indicated by an arrow in the drawing around the rotation shaft 21a of the base 25. On the upper surface of the turntable 21, a circumferential groove 20 centering on the rotation shaft 21a is formed.
The hopper 22 drops and supplies the measured particle group P filled therein toward the inside of the groove 20 of the turntable 21.
The filler 23 uniformly fills the inside of the groove 20 with the particle group P to be measured by applying vibration or the like to the particle group P to be measured supplied inside the groove 20.

The transfer mechanism 24 includes an ejector 24a, a suction pipe 24b having one end opened downward and the other end connected to the ejector 24a, an air supply pipe 24d for supplying high-pressure air from a cylinder 24c to the ejector 24a, and one end thereof An aerosol transfer pipe 24f to which an ejection nozzle 24e that is connected to the ejector 24a and opens at the other end toward the measurement space is mounted.
According to such a transfer mechanism 24, the particle group P to be measured sucked by the suction pipe 24b is mixed into the high-pressure air in the ejector 24a, transferred through the aerosol transfer pipe 24f, and the aerosol transfer pipe 24f. The aerosol S is ejected from the ejection nozzle 24e attached to the tip to the measurement space.

The irradiation optical system 12 is installed on the left side of the particle size distribution measuring apparatus 101. Specifically, the laser light source 11, the condensing lens 12a, the spatial filter 12b, and the collimator 12c are arranged in this order from the left.
In such a configuration of the irradiation optical system 12, the laser light generated by the laser light source 11 passes through the condenser lens 12 a, the spatial filter 12 b, and the collimator 12 c to become parallel light, and is directed forward (from left to right in the figure). The measurement space is irradiated so as to go to (F).
Accordingly, if the aerosol S passes through the measurement space, the laser light is diffracted and scattered by the measured particle group P in the measurement space, and a light intensity distribution pattern of the diffracted / scattered light is generated spatially. Become.

The detection optical system 14 is installed on the right side of the particle size distribution measuring apparatus 101. Specifically, a condenser lens 14a and a ring detector (forward scattered light sensor) 14b are arranged in this order from the left.
The ring detector 14b has 64 photodetecting elements having ring-shaped or semi-ring-shaped light receiving surfaces having different radii arranged concentrically with the optical axis of the condenser lens 14a as the center, Light having a diffraction / scattering angle corresponding to each position is incident on each photodetecting element. Therefore, the output signal of each light detection element represents the light intensity for each diffraction / scattering angle.
In such a configuration of the detection optical system 14, the diffracted / scattered light within 60 ° with respect to the forward direction is condensed on the light receiving surface of the ring detector 14b via the condenser lens 14a, and is diffracted in a ring shape.・ Become a scattered image.

Further, the scattered light toward the side (backward upward direction) exceeding 60 ° with respect to the front direction is detected by a side scattered light sensor (not shown).
Further, the scattered light in the rear (backward downward direction) exceeding 60 ° with respect to the front direction is detected by five back scattered light sensors (not shown).
The backscattered light sensor has five light detecting elements arranged in a straight line from the left to the right, and each light detecting element receives light having a diffraction / scattering angle according to the position. It is supposed to be incident. Therefore, the output signal of each light detection element represents the light intensity for each diffraction / scattering angle.
The output signals of the 70 light detection elements of the ring detector 14b, the side scattered light sensor, and the back scattered light sensor are sequentially digitized by the data sampling circuit 15 including an amplifier, a multiplexer, and an A / D converter. The light intensity distribution data of the scattered light is transmitted to a general-purpose computer 117.

The computer 117 includes a CPU 140 and a memory 160, and a display device 52 having a monitor screen and an input device 51 having a keyboard 51a and a mouse 51b are connected to each other.
The function processed by the CPU 140 will be described as a block. The light intensity distribution acquisition unit 141 that acquires light intensity distribution data, the particle size distribution calculation unit 43 that calculates the particle size distribution of the particle group P to be measured, and the sample supply device 2 are described below. And a sample supply control unit 42 for controlling.
The memory 160 also has a light intensity distribution storage area 162 for storing light intensity distribution data, a known calculation based on the refractive index of particles and air (medium) L, the Fraunhofer diffraction theory and the Mie scattering theory. And a data storage area 61 for storing formulas and the like.

  The sample supply control unit 42 performs control to supply the aerosol S from the sample supply mechanism 2 to the measurement space when being input by the measurer with the input device 51 so as to measure the aerosol S.

When the light intensity distribution acquisition unit 141 determines that the aerosol S passes through the measurement space, the light intensity distribution acquisition unit 141 irradiates the measurement space with the laser light from the irradiation optical system 12, and also the ring detector 14b, the side scattered light sensor, and the backscatter. The light intensity detected by each of the 70 light detection elements of the optical sensor is detected so as to be integrated, and when it is determined that the aerosol S does not pass through the measurement space, the light detection is performed by each of the 70 light detection elements. The control of acquiring the light intensity distribution data and storing it in the light intensity distribution storage area 162 is performed by terminating the integration of the respective light intensities.
Here, FIG. 5A is a diagram illustrating an example of light intensity distribution data acquired by the light intensity distribution acquisition unit. The vertical axis represents the light intensity, and the horizontal axis represents the element number of the light detection element. For the light intensity on the vertical axis, the maximum value of the light intensity that can be detected by the light detection element in each of the ring detector, the side scattered light sensor, and the back scattered light sensor is 100%.

The particle size distribution calculation unit 43 uses the light intensity distribution data obtained by the light intensity distribution acquisition unit 141 and the refractive indexes of the particles and air L to perform a known calculation based on Fraunhofer diffraction theory or Mie's scattering theory. By performing, control which calculates the particle size distribution of the to-be-measured particle group P contained in the aerosol S is performed.
Here, FIG. 5B is a diagram illustrating an example of the particle size distribution data calculated by the particle size distribution calculating unit 43. The vertical axis is the particle amount, and the horizontal axis is the particle diameter.

By the way, the numerical values of the light intensity data from the 70 light detection elements of the ring detector 14b, the side scattered light sensor, and the back scattered light sensor depend on the concentration of the particle group P to be measured. Therefore, when the amount of the particle group P to be measured that can be filled in the hopper 22 is small, only the aerosol S containing the particle group P to be measured having a low concentration can be obtained, and as a result, as shown in FIG. Thus, the numerical value of the light intensity data becomes small. Therefore, there has been a problem that the particle size distribution of the particle group P to be measured cannot be calculated based on the S / N of a good output signal.
Therefore, even when measuring an aerosol S containing a low concentration of particles to be measured P, a particle size distribution provided with a sample recovery mechanism 3 that recovers the aerosol S that has passed through the measurement space in order to increase the numerical value of the light intensity data. A measuring apparatus 101 is disclosed (see, for example, Patent Document 1).

The sample collection device 3 includes a suction pipe 31, a collection container 32 including a lower chamber 32a and an upper chamber 32b, an exhaust pipe 33, and a pump 34.
The suction pipe 31 is arranged so that one end side 31a is opened and faces the ejection nozzle 24e, and the other end side 31b is connected to the lower chamber 32a of the recovery container 32.
The lower chamber 32a and the upper chamber 32b of the collection container 32 are partitioned by a filter 32c. The filter 32c allows air to pass but does not allow the measured particle group P to pass. The upper chamber of the collection container 32 is connected to the pump 34 via the exhaust pipe 33.
According to such a sample collection device 3, when the pump 34 is driven, the particle group P to be measured in the measurement space is sucked from the suction pipe 31 together with the air L, and the particle group P to be measured is located in the lower chamber of the collection container 32. It will be collected in 32a. The measured particle group P collected in the lower chamber 32a is returned to the hopper 22 of the sample supply device 2 so that it can be used again for measurement.

According to such a particle size distribution measuring apparatus 101, the particle size distribution calculating unit 43 performs the first light intensity distribution data obtained by the light intensity distribution obtaining unit 141 and the second time obtained by the light intensity distribution obtaining unit 141. And the third light intensity distribution data obtained by the light intensity distribution acquisition unit 141 are integrated, and the measured particle group P included in the aerosol S is used by using the integrated light intensity distribution data. The particle size distribution is calculated.
Here, FIG. 6A is a diagram illustrating an example of three times of light intensity distribution data acquired by the light intensity distribution acquisition unit, and FIG. 6B is an example of integrated light intensity distribution data. FIG. 6C is a diagram illustrating an example of the particle size distribution data calculated by the particle size distribution calculation unit.
Thereby, the numerical value of light intensity data can be enlarged. As a result, since the S / N of the output signal is improved, the particle size distribution of the particle group P to be measured is calculated with high accuracy.

JP 2008-157631 A

By the way, in the particle size distribution measuring apparatus 101 as described above, when measuring the particle group P to be measured with a small absolute amount, the number of integrations that is considered necessary to obtain an accurate particle size distribution of the particle group P to be measured in advance. (N) is input as, for example, three times.
However, even if the measurer determines the number of times of integration (n) by looking at the absolute amount of the particle group P to be measured, the value of the integrated light intensity data is still small, or this time the integrated light intensity data The number of sometimes became too large.
Therefore, an object of the present invention is to provide a particle size distribution measuring apparatus capable of calculating the particle size distribution of a group of particles to be measured included in the object to be measured using a light intensity distribution having an optimum light intensity.

  The particle size distribution measuring apparatus of the present invention made to solve the above-described problem has a light source that emits measurement light and a plurality of light detection elements that detect light intensity, and the light intensity is detected by the plurality of light detection elements. A detector for detecting distribution, a measurement space for passing a measurement object including a medium and a measured particle group between the light source and the detector, and a measurement light from the light source. A light intensity distribution acquisition unit that detects and acquires a light intensity distribution generated by irradiating the measurement object with a detector, and a light intensity distribution acquired by the light intensity distribution acquisition unit, A particle size distribution measuring device including a particle size distribution calculating unit for calculating a particle size distribution of the included particles to be measured, wherein the light intensity distribution acquiring unit integrates the light intensities detected by the light detection elements, respectively. Detecting at least one light detection Based on the integrated light intensity in the device, and the light intensity detected by each light detecting element so as to determine whether to end by integrating respectively.

Here, as the “measurement light”, laser light is preferable, but not limited to this, light by an LED, light dispersed by a spectroscope, light having a wavelength range limited by an interference filter, a bandpass filter, or the like is used. May be.
The “medium” may be any medium that can disperse the particles to be measured inside, and examples thereof include liquids such as water and oil, gels, solids, and gases such as air.
Further, the “light intensity” does not have to be the numerical value itself detected by the light detection element, and there may be the light intensity of the initial excess light that has already been detected before measuring the object to be measured. The difference between the numerical value detected by the light detection element and the numerical value of the initial surplus light is preferable.

According to the particle size distribution measuring apparatus of the present invention, the light intensity distribution acquisition unit detects so as to integrate the light intensities detected by the respective light detection elements, and the light intensity distribution acquisition unit accumulates at least one light detection element. Based on the light intensity, it is determined whether or not to end the integration of the light intensity detected by each light detection element. Therefore, if the value of the light intensity data is small, the light intensity detected by each light detection element is continuously integrated, and the light intensity data is detected by each light detection element before the light intensity data becomes too large. This completes the integration of the respective light intensities. That is, the integrated light intensity data does not remain small or the integrated light intensity data does not become too large.
Thereafter, the particle size distribution calculation unit calculates the particle size distribution of the particle group to be measured included in the object to be measured using the light intensity distribution acquired by the light intensity distribution acquisition unit.

  As described above, according to the particle size distribution measuring apparatus of the present invention, the particle size distribution of the particle group to be measured included in the object to be measured can be calculated using the light intensity distribution with the optimum light intensity.

(Means and effects for solving other problems)
Further, in the particle size distribution measuring apparatus of the present invention, the light intensity distribution acquisition unit detects the light intensity detected by each light detection element so as to be integrated, and integrates at least one light detection element. When the measured light intensity is equal to or higher than the threshold value, the integration of the light intensity detected by each light detection element may be terminated.
Here, the “threshold value” is an arbitrary numerical value predetermined by a designer or the like, and is, for example, 50% of the maximum value that can be detected by the light detection element.

  In the particle size distribution measuring apparatus of the present invention, the light intensity distribution acquisition unit detects so as to integrate the light intensities detected by the light detection elements when the object to be measured is supplied to the measurement space. Then, when there is no object to be measured supplied to the measurement space, the integration of the light intensity detected by each light detection element is stopped, and then the object to be measured is supplied to the measurement space. And restarting the detection so as to integrate the light intensities detected by the respective light detection elements, and detecting each light based on the light intensity accumulated in at least one of the light detection elements. You may make it determine whether it complete | finishes each integrating | accumulating the light intensity detected with an element.

  Furthermore, in the particle size distribution measuring apparatus of the present invention, a sample supply mechanism that supplies an object to be measured to the measurement space, a sample recovery mechanism that recovers an object to be measured that has passed through the measurement space, and a sample supply mechanism that receives from the sample supply mechanism. A measurement object is supplied to the measurement space, and then a sample supply control unit that returns the measurement object collected by the sample recovery mechanism to the sample supply mechanism and supplies the measurement object to the measurement space again. Also good.

1 is a schematic configuration block diagram showing an overall configuration of a particle size distribution measuring apparatus according to an embodiment of the present invention. It is a figure which shows an example of light intensity distribution data and particle size distribution data. It is a flowchart for demonstrating a calculation method. It is a schematic block diagram which shows the whole structure of the conventional particle size distribution measuring apparatus. It is a figure which shows an example of light intensity distribution data and particle size distribution data. It is a figure which shows an example of light intensity distribution data and particle size distribution data.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and includes various modes without departing from the spirit of the present invention.

FIG. 1 is a schematic block diagram showing the overall configuration of a particle size distribution measuring apparatus according to an embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the thing similar to the particle size distribution measuring apparatus 101. FIG.
The particle size distribution measuring apparatus 1 includes a measurement space placement unit 13 that places a measurement space, an irradiation optical system 12 that irradiates the measurement space with laser light, a detection optical system 14 that detects a light intensity distribution, and a measurement space. A sample supply device 2 that supplies an aerosol (measurement object) S, a data sampling circuit 15, a communication control circuit 16, and a computer (control unit) 17 that controls the entire particle size distribution measurement device 1 are provided.
In the present embodiment, the particle size distribution of the particle group P to be measured is calculated by measuring the aerosol S in which the particle group P to be measured is dispersed in the air (medium) L.

The computer 17 includes a CPU 40 and a memory 60, and a display device 52 having a monitor screen and an input device 51 having a keyboard 51a and a mouse 51b are connected to each other.
The function processed by the CPU 40 will be described as a block. The light intensity distribution acquisition unit 41 that acquires light intensity distribution data, the particle size distribution calculation unit 43 that calculates the particle size distribution of the particle group P to be measured, and the sample supply device 2 And a sample supply control unit 42 for controlling.
The memory 60 also includes a light intensity distribution storage area 62 for storing light intensity distribution data, a refractive index of particles and air (medium) L, known calculations based on Fraunhofer diffraction theory and Mie scattering theory. And a data storage area 61 for storing formulas and the like. The light intensity distribution storage area 62 stores in advance a light intensity threshold value I _th for completing the integration of the light intensity detected by each of the 70 light detection elements.

  When the sampler inputs the input device 51 so as to measure the aerosol S by the measurer, the sample supply control unit 42 supplies the aerosol S from the sample supply mechanism 2 to the measurement space, and from the light intensity distribution acquisition unit 41. Based on the end signal, control is performed to end the supply of the aerosol S from the sample supply mechanism 2 to the measurement space.

When the light intensity distribution acquisition unit 41 determines that the aerosol S passes through the measurement space, the light intensity distribution acquisition unit 41 irradiates the measurement space with the laser light from the irradiation optical system 12, and also the ring detector 14b, the side scattered light sensor, and the backscatter. The light intensity detected by each of the 70 light detection elements of the optical sensor is detected so as to be integrated, and when it is determined that the aerosol S does not pass through the measurement space, the light detection is performed by each of the 70 light detection elements. When the determination is made that the aerosol S has passed through the measurement space, it is detected by each of the 70 light detection elements. and the light intensity to be resumed to continue to detect as integrating respectively, at least one light detecting element (e.g., element number 59) threshold light intensity is accumulated in I _t When it becomes _h or more, the light intensity distribution data is acquired and stored in the light intensity distribution storage area 62 by completing the integration of the light intensity detected by each of the 70 light detection elements. Then, control is performed to transmit an end signal to the sample supply control unit 42 (see FIG. 2B).

At this time, as a method for determining whether or not the aerosol S passes through the measurement space, whether or not any of the light intensities detected by the light detection element exceeds a certain value is used as a guideline. When it is determined that the value is below a certain value, it is assumed that the aerosol S does not pass through the measurement space.
When it is determined that the aerosol S passes through the measurement space, for example, in the light intensity distribution data shown in FIG. 2A, the light intensity integrated in all the light detection elements is the threshold value I. Since it is less than _th , the light intensity detected by each light detection element is detected so as to be integrated, and the light intensity distribution data shown in FIG. since the integrated light intensity in the light detecting element 59) is the threshold value I _th concludes that integrating the light intensity detected by each light detecting element, respectively. That is, the light intensity distribution acquisition unit 41 obtains the light intensity distribution data shown in FIG.

The particle size distribution calculation unit 43 uses the light intensity distribution data obtained by the light intensity distribution acquisition unit 41 and the refractive indexes of the particles and the air L to perform a known calculation based on Fraunhofer diffraction theory or Mie scattering theory. By performing, control which calculates the particle size distribution of the to-be-measured particle group P contained in the aerosol S is performed.
Here, FIG. 2C is a diagram illustrating an example of the particle size distribution data calculated by the particle size distribution calculation unit 43. The vertical axis is the particle amount, and the horizontal axis is the particle diameter. The bar graph represents the amount of particles as a differential value related to the particle size, and the curved graph with white circles represents the amount of particles as an integrated value related to the particle size.

Here, a calculation method for calculating the particle size distribution of the particle group P to be measured will be described. FIG. 3 is a flowchart for explaining the calculation method.
First, in the process of step S <b> 101, the measurer stores the measured particle group P in the sample supply mechanism 2.
Next, in the process of step S102, the measurer inputs with the input device 51 so as to measure the aerosol S.

Next, in the process of step S103, the sample supply controller 42 supplies the aerosol S from the sample supply mechanism 2 to the measurement space.
Next, in the process of step S104, the light intensity distribution acquisition unit 41 determines whether or not the aerosol S passes through the measurement space. If it is determined that the aerosol S has not passed through the measurement space, the process of step S104 is repeated.
On the other hand, if it is determined that the aerosol S passes through the measurement space, the light intensity distribution acquisition unit 41 in the process of step S105, each of the 70 light beams of the ring detector 14b, the side scattered light sensor, and the back scattered light sensor. Detection is performed so that the light intensities detected by the detection elements are integrated.

Next, in the process of step S106, the light intensity distribution obtaining unit 41 determines whether the optical intensity is integrated in at least one of the light detecting element is equal to or greater than the threshold value I _th. When it is determined that the light intensity integrated in all the light detection elements is not _{equal to} or greater than the threshold value Ith, in the process of step S107, the light intensity distribution acquisition unit 41 determines whether the aerosol S passes through the measurement space. Determine whether. If it is determined that the aerosol S passes through the measurement space, the process returns to step S105.
On the other hand, if it is determined that the aerosol S has not passed through the measurement space, the light intensity distribution acquisition unit 41 stops accumulating the light intensities detected by the 70 light detection elements in the process of step S108. To do.
Then, the process returns to step S103. That is, in the first measurement, the light intensity did not exceed the threshold value I _th, will perform the second measurement.

On the other hand, in the processing of step S106, when it is determined that the light intensity is integrated in at least one of the light detecting element is equal to or greater than the threshold value I _th is in the process of step S109, the sample supply control unit 42, the sample feed mechanism 2 The supply of aerosol S to the measurement space is stopped.
Next, in the process of step S110, the particle size distribution calculation unit 43 uses the light intensity distribution data obtained by the light intensity distribution acquisition unit 41 and the refractive indexes of the particles and the air L to determine Fraunhofer diffraction theory and Mie's. The particle size distribution of the measured particle group P included in the aerosol S is calculated by performing a known calculation based on the scattering theory.
And when the process of step S110 is complete | finished, this flowchart is complete | finished.

  As described above, according to the particle size distribution measuring apparatus 1, the particle size distribution of the particle group to be measured included in the object to be measured can be calculated using the light intensity distribution having the optimum intensity.

  The present invention can be used in a particle size distribution measuring apparatus that measures the particle size distribution of a group of particles to be measured included in a measurement object using an optical technique.

DESCRIPTION OF SYMBOLS 1 Particle size distribution measuring apparatus 11 Laser light source 13 Measurement space arrangement | positioning part 14 Detector 41 Light intensity distribution acquisition part 43 Particle size distribution calculation part

Claims (4)

A light source that emits measurement light;
A detector having a plurality of light detection elements for detecting light intensity, and detecting a light intensity distribution by the plurality of light detection elements;
A measurement space disposition unit for disposing a measurement space that allows a measurement object including a medium and a group of particles to be measured to pass between the light source and the detector;
A light intensity distribution acquisition unit that detects and acquires a light intensity distribution generated by irradiating an object to be measured with measurement light from the light source; and
Using the light intensity distribution acquired by the light intensity distribution acquisition unit, a particle size distribution measuring device comprising a particle size distribution calculating unit for calculating a particle size distribution of a measured particle group included in the measured object,
The light intensity distribution acquisition unit detects so as to integrate the light intensities detected by the respective light detection elements, and each light detection element is based on the light intensity accumulated in at least one light detection element. A particle size distribution measuring apparatus for determining whether or not to end the integration of the light intensities detected in step (b).   The light intensity distribution acquisition unit performs detection so as to integrate the light intensities detected by the respective light detection elements, and when the light intensity integrated in at least one light detection element is equal to or greater than a threshold value. The particle size distribution measuring apparatus according to claim 1, wherein the integration of the light intensities detected by the light detection elements is terminated. When the object to be measured is supplied to the measurement space, the light intensity distribution acquisition unit detects the light intensities detected by the respective light detection elements so as to integrate the objects, and supplies the object to be supplied to the measurement space. When there is no measurement object, stop integrating the light intensity detected by each light detection element,
Thereafter, when the object to be measured is supplied to the measurement space, at least one photodetecting element is resumed so as to resume detection so as to integrate the light intensities detected by the photodetecting elements. 3. The granularity according to claim 1, wherein it is determined whether or not to end the integration of the light intensities detected by the respective light detection elements based on the light intensities integrated in the step. Distribution measuring device. A sample supply mechanism for supplying an object to be measured to the measurement space;
A sample collection mechanism for collecting an object to be measured that has passed through the measurement space;
A sample supply control unit that supplies the measurement object from the sample supply mechanism to the measurement space, and then returns the measurement object collected by the sample recovery mechanism to the sample supply mechanism and supplies the measurement object to the measurement space again. The particle size distribution measuring apparatus according to claim 3, comprising:

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