JP2012132700A - Particle measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the number of particles and particle diameters for particles contained in sample gas without using sheath gas flow.SOLUTION: A particle measuring apparatus includes: a charging mechanism 3 for charging particles contained in sample gas; a collection electrode 9 for collecting the particles charged by the charging mechanism 3; sample gas introduction mechanisms 1, 7, 15, 17, 19 for flowing the sample gas passed through the charging mechanism 3 to the surface of an insulator of the collection electrode 9; a collection electrode potential switching mechanism 21 for switching collection voltage to emission voltage to be applied to the collection electrode 9; a counter electrode 11 arranged opposite to the collection electrode 9 at a predetermined interval with the collection electrode 9; a current detector 23 which detects the particles by detecting current flowing to the counter electrode 11 resulting from adhesion of the charged particles emitted from the collection electrode 9; and flight time measuring parts 27, 29 which calculate particle flight time from the collection electrode 9 to the counter electrode 11 for every particle to be detected by the current detector 23.

Description

  The present invention relates to an apparatus for measuring the number of particles contained in environmental gas, for example, a particle measuring apparatus for measuring the number of particles contained in automobile exhaust gas in real time.

  As an apparatus for measuring the number of particles contained in environmental gas such as automobile exhaust gas, a differential type or integral type electric mobility measuring apparatus is known (for example, see Patent Document 1). This electric mobility measuring device is known to have a particle size classification function of the order of nm (nanometer).

FIG. 6 is a schematic diagram for explaining a classification mechanism used in a conventional differential mobility analyzer (DMA).
A space 105 through which the sheath gas introduced from the sheath gas introduction port 101 and rectified by the rectification mechanism 103 flows is provided. A sample gas supply port 107 for introducing the sample gas is provided on the side surface of the space 105. A counter electrode 109 is provided facing the sample gas supply port 107. A gas suction port 111 is provided below the counter electrode 109.

  A sample gas containing particles charged by the charging device is introduced into the space 105 from the sample gas supply port 107. The particles introduced into the space 105 move downstream with the sheath gas. At this time, the particles are affected by the electric field generated by the counter electrode 109 and are attracted toward the counter electrode 109 at a speed corresponding to the electric mobility of each particle. Then, only particles in a desired particle size range that reach the gas suction port 111 in a predetermined locus are taken out.

  In addition, for measuring particles with a large particle size that cannot be classified with a differential electric mobility measuring device, there is a method in which the particle is irradiated with light of a specific wavelength and the number of pulses of light scattered at an angle corresponding to the particle size is measured. Has been used.

Japanese Patent No. 3435015

  In the classification of particles in the differential electric mobility measuring device, as described above, the particles move to the opposite electrode side across the sheath gas flow by the electrostatic attraction generated by applying an electric field in the direction perpendicular to the sheath gas flow. To do. In the movement process, the particles are subjected to a resistance determined by the particle size from the sheath gas flow, so that the particles can be classified.

However, since such classification requires a sheath gas flow, there is a problem that the configuration and control of the apparatus are complicated and the apparatus is expensive.
Furthermore, since the particle size resolution is determined by the quotient of the sheath gas flow rate and the sample flow rate, there is a limit to increasing the sample flow rate in order to increase the signal amount.

A Faraday cup ammeter used as a particle number counter of a differential electric mobility measuring device is inexpensive, but the current value obtained from charged collected particles is several tens of fA (femtoampere, 10 ^-15 A). ) There is a problem that reliable measurement is not possible unless the particle concentration is above. A nuclear condensation particle counter can be used to measure a low particle concentration, but the nuclear condensation particle counter is expensive.
In addition, the optical particle counter is less expensive than the differential electric mobility measuring device, but has a problem that it cannot measure particles having a particle size of 300 nm or less.
Furthermore, the nuclear condensation particle counter and the optical particle counter could only detect the particle number concentration, and the particle size of the particles could not be measured.

  An object of this invention is to provide the particle | grain measuring apparatus which can measure a particle number and a particle size, without using a sheath gas flow.

  The particle measuring apparatus according to the present invention includes a charging mechanism for charging particles contained in a sample gas, and at least a portion in contact with the sample gas is covered with an insulator, and particles charged by the charging mechanism are placed on the surface of the insulator. A collecting electrode for collecting, a sample gas introducing mechanism for flowing the sample gas that has passed through the charging mechanism to the insulator surface of the collecting electrode, and a collecting voltage on the collecting electrode And a collecting electrode potential switching mechanism for switching and applying a discharge voltage, the collecting electrode facing the collecting electrode at a predetermined interval, and the collecting electrode A current detector for detecting particles by detecting a current flowing through the counter electrode due to adhesion of charged particles emitted from the electrode for the collection, and for each particle detected by the current detector From the electrode to the counter And a, and flight time measurement unit for obtaining the particle flight time to.

  In the particle measuring apparatus of the present invention, particles contained in the sample gas are charged by the charging mechanism by the charging mechanism. The sample gas that has passed through the charging mechanism is caused to flow from the sample gas introduction mechanism to the insulator surface of the collecting electrode in a state where a collecting voltage is applied to the collecting electrode by the collecting electrode potential switching mechanism. The charged particles are collected on the insulator surface of the collecting electrode. After the sample gas is allowed to flow over the insulator surface of the collecting electrode for a predetermined time, the space between the collecting electrode and the counter electrode is made in a windless state, and then collected by the collecting electrode potential switching mechanism. The voltage applied to the electrode is switched from the collecting voltage to the discharging voltage, and the potential of the collecting electrode is inverted. The collected charged particles are attracted to the counter electrode by Coulomb force. At this time, the discharged charged particles are subjected to a drag that is proportional to the particle velocity and depends on the particle size due to the gas existing between the electrodes. Eventually, the charged particles fly toward the counter electrode at a constant speed at which the Coulomb force and the drag force are balanced. The charged particles that have reached the counter electrode release their charge on the counter electrode. The current detector detects particles by detecting a current flowing through the counter electrode due to the discharge of the charge of the charged particles. The number of particles can be determined by determining the number of times the current flows through the counter electrode. The time-of-flight measurement unit obtains the particle flight time from the collection electrode to the counter electrode for each particle detected by the current detector. The flight time of charged particles is determined by the number of charges and the particle size of the particles. That is, the particle size can be calculated from this flight time.

  In the particle measuring apparatus of the present invention, the sample gas introduction mechanism has a size smaller than the distance between the collection electrode and the counter electrode, and is disposed closer to the collection electrode than the counter electrode. An example can be given in which the sample gas is flowed from the sample gas supply port formed to the surface of the insulator of the collecting electrode.

Moreover, the sample gas introduction mechanism can be exemplified by flowing the sample gas along the longitudinal direction of the insulator surface of the collecting electrode.
In addition, the sample gas introduction mechanism may include an example in which the sample gas is flowed at an angle with respect to the insulator surface so that the sample gas is directed toward the insulator surface of the collecting electrode.

By the way, depending on the particle size of the charged particles collected on the collection electrode, the van der Waals force acting between the particles and the collection electrode is larger than the Coulomb force, and the potential of the collection electrode is inverted. There is a possibility that the charged particles are not released only by this.
Therefore, in the particle measuring apparatus of the present invention, a mechanism that promotes the detachment of particles attached to the collection electrode, for example, a heating mechanism that heats the collection electrode, a vibration mechanism that vibrates the collection electrode, or for collection You may make it further provide the photoexcitation mechanism which provides energy to the charged particle collected by the electrode.

Any heating mechanism may be used as long as it has a function capable of heating the collection electrode, such as a heater that generates heat by electric energy or a light source that is heated by light irradiation. .
Any vibration mechanism may be used as long as it has a function of vibrating the collection electrode, such as a vibrator using a piezoelectric element.

  The light excitation mechanism may be provided with any light source and optical system as long as it has a function capable of irradiating light including light having a wavelength capable of imparting energy to the charged particles collected by the collection electrode. . For example, the light excitation mechanism may include a lamp, a laser, or a bandpass filter for irradiating light of a specific wavelength. As a result, only particles having a specific chemical structure that absorbs light of a specific wavelength can be selectively excited and vibrated to fly toward the counter electrode, and the chemical structure contained in the excited particles Can be specified.

  The particle measuring apparatus of the present invention charges particles contained in a sample gas by a charging mechanism and charges the sample gas from the sample gas introduction mechanism in a state where a collection voltage is applied to the collection electrode by the collection electrode potential switching mechanism. The sample gas that has passed through the mechanism is made to flow on the insulator surface of the collecting electrode to collect charged particles on the insulator surface of the collecting electrode, and after collecting the charged particles for a predetermined time, the collecting electrode and Charged particles collected by applying a discharge voltage to the collection electrode by the collection electrode potential switching mechanism and reversing the potential of the collection electrode after leaving the space between the counter electrodes in a windless state. To the counter electrode side, the current flowing through the counter electrode is detected by the current detector to detect the particles, and the time-of-flight measuring unit detects each particle detected by the current detector from the collecting electrode to the counter electrode. The particle flight time up to Without using a gas stream, it is possible to measure the particle number and particle size for particles contained in the sample gas.

  In the particle measuring apparatus of the present invention, the sample gas introduction mechanism has a size smaller than the distance between the collection electrode and the counter electrode, and is a sample gas supply arranged closer to the collection electrode than the counter electrode If the sample gas is allowed to flow from the mouth to the insulator surface of the collection electrode, the sample gas supply port size is equal to or greater than the distance between the collection electrode and the counter electrode. Compared with the case where the supply port is arranged closer to the counter electrode than the collection electrode, the charged particles can be collected on the insulator surface of the collection electrode in a short time. Furthermore, since charged particles can be collected at a short distance, the apparatus can be downsized.

  In addition, the sample gas introduction mechanism allows the sample gas to flow along the longitudinal direction of the collecting electrode, compared to the case where the sample gas flows along the short direction of the collecting electrode. The time for passing through the vicinity of the insulator surface of the collecting electrode can be lengthened, and the charged particles can be reliably collected.

  Further, the sample gas introduction mechanism allows the sample gas to flow through the collector electrode by flowing the sample gas at an angle with respect to the insulator surface so that the sample gas is directed toward the insulator surface of the collector electrode. Charged particles can be collected reliably and in a short time compared to the case of flowing in parallel with the insulator surface.

  In the particle measuring apparatus of the present invention, a mechanism that promotes detachment of particles attached to the collecting electrode, for example, a heating mechanism that heats the collecting electrode, a vibration mechanism that vibrates the collecting electrode, or a collecting electrode If a photoexcitation mechanism for applying energy to the collected charged particles is further provided, the charged particles collected on the collecting electrode can be easily separated from the collecting electrode.

  Furthermore, if the photoexcitation mechanism is equipped with a lamp, laser or bandpass filter for irradiating light of a specific wavelength, particles having a specific chemical structure that absorbs light of a specific wavelength. Can be selectively excited and vibrated to fly toward the counter electrode, and the chemical structure contained in the excited particles can be identified.

It is a schematic block diagram for demonstrating one Example. It is a schematic block diagram for demonstrating the state by which the charged particle was collected in the Example. It is a schematic block diagram for demonstrating the state to which a charged particle flies in the Example. It is a schematic block diagram for demonstrating another Example. It is a schematic block diagram for demonstrating other Example. It is the schematic for demonstrating the classification mechanism used for the conventional differential electric mobility measuring apparatus.

FIG. 1 is a schematic configuration diagram for explaining an embodiment.
A charging mechanism 3 is provided in the sampling line 1 in which the sample gas is taken in from the sample introduction port 1a and the sample gas flows inside. The charging mechanism 3 is for charging particles contained in the sample gas. The sample discharge port 1b of the sampling line 1 is led into the sealable housing 5.

A flow path limiting plate 7, a collection electrode 9, and a counter electrode 11 are provided inside the housing 5.
The flow path restriction plate 7 is disposed between the space between the collection electrode 9 and the counter electrode 11 and the discharge port 1 b of the sampling line 1. The flow path restriction plate 7 forms a sample gas supply port 13 near the collection electrode 9 rather than the counter electrode 11. The sample gas supply port 13 is formed with a size smaller than the distance between the collecting electrode 9 and the counter electrode 11.
The collecting electrode 9 is covered with an insulator (not shown) at least at a portion in contact with the sample gas introduced into the housing 5. The collection electrode 9 is formed with a width in the direction perpendicular to the paper surface, and the longitudinal direction of the collection electrode 9 is arranged in a direction along the flow of the sample gas.
The counter electrode 11 is arranged to face the collecting electrode 9 with a predetermined distance from the collecting electrode 9.

An exhaust line 15 is connected to the housing 5. The introduction port 15 a of the exhaust line 15 is arranged at a position opposite to the flow path restriction plate 7 with respect to the space between the collection electrode 9 and the counter electrode 11 inside the housing 5. The sample discharge port 15 b of the exhaust line 15 is disposed outside the housing 5. A flow rate adjusting valve 17 and an exhaust pump 19 are provided in the exhaust line 15.
In this embodiment, the sampling line 1, the flow restriction plate 7, the exhaust line 15, the flow control valve 17 and the exhaust pump 19 constitute a sample gas introduction mechanism of the particle measuring apparatus of the present invention.

A collecting electrode potential switching mechanism 21 for switching and applying a collecting voltage and a discharging voltage to the collecting electrode 9 is provided. The collection electrode potential switching mechanism 21 applies, for example, a positive voltage as the collection voltage and a negative voltage as the emission voltage to the collection electrode 9 in a switchable manner.
A current detector 23 for detecting a current flowing through the counter electrode 11 is provided. The current detector 23 is for detecting a current that flows through the counter electrode 11 due to adhesion of charged particles emitted from the collecting electrode 9.

A control unit 25 is provided. The control unit 25 includes a central processing unit (CPU) 27, a timer (Timer) 29, a digital signal output unit (D / O) 31, and an analog signal input unit (A / I) 33.
The central processing unit 27 and the timer 29 obtain the particle flight time from the collection electrode 9 to the counter electrode 11 for each particle detected by the current detector 23, and the flight time measurement unit in the particle measurement device of the present invention. Configure.
The digital signal output unit 31 is for transmitting a control signal to the exhaust pump 19 and the collecting electrode potential switching mechanism 21.
The analog signal input unit 33 is for taking in the detection signal of the current detector 23.

FIG. 2 is a schematic configuration diagram for explaining a state in which charged particles are collected in this embodiment. FIG. 3 is a schematic configuration diagram for explaining a state in which charged particles fly in this embodiment.
The operation of this embodiment will be described with reference to FIGS.

  When the exhaust pump 19 is operated by the control of the control unit 25, the sample gas is introduced into the sampling line 1 from the sample introduction port 1a at the flow rate adjusted by the flow rate adjustment valve 17. The introduced sample gas reaches the charging mechanism 3, and the particles contained in the sample gas are charged to a negative charge, for example.

  The sample gas that has passed through the charging mechanism 3 is introduced into the housing 5 through the outlet 1 b of the sampling line 1. The sample gas introduced into the housing 5 flows in a state where the collection electrode potential switching mechanism 21 applies a positive collection voltage to the collection electrode 9 under the control of the control unit 25. The gas flows through the sample gas supply port 13 formed by the limiting plate 7 to the insulator surface (not shown) of the collecting electrode 9. The charged particles contained in the sample gas are collected on the insulator surface of the collecting electrode 9 (see FIG. 2). Since the portion of the collection electrode 9 that is in contact with the sample gas is covered with an insulator, teaching of the charge from the charged particles to the collection electrode 9 is not performed.

  The sample gas supply port 13 has a size smaller than the distance between the collection electrode 9 and the counter electrode 11 and is disposed closer to the collection electrode 9 than the counter electrode 11. Is equal to or larger than the distance between the collection electrode 9 and the counter electrode 11, or when the sample gas supply port 13 is disposed closer to the counter electrode 11 than the collection electrode 9. In comparison with the above, charged particles can be collected on the insulator surface of the collecting electrode 9 in a short time. Furthermore, since charged particles can be collected at a short distance, the apparatus can be downsized.

Furthermore, since the sample gas is caused to flow along the longitudinal direction of the collecting electrode 9, the sample gas is collected in comparison with the case where the sample gas is caused to flow along the short direction of the collecting electrode 9. It is possible to lengthen the time for passing through the vicinity of the insulator surface, and it is possible to reliably collect charged particles.
Further, the sample gas is flowed at an angle with respect to the insulator surface of the collecting electrode 9 so as to be directed to the insulator surface of the collecting electrode 9 by the arrangement of the flow path restriction plate 7 and the sample gas supply port 13. As compared with the case where the sample gas is caused to flow in parallel to the insulator surface of the collecting electrode 9, the charged particles can be collected reliably and in a short time.

  After the sample gas is allowed to flow on the insulator surface of the collecting electrode 9 for a predetermined time, the exhaust pump 19 is stopped under the control of the control unit 25. Further, after a predetermined time has elapsed, the space between the collection electrode 9 and the counter electrode 11 becomes no-wind, and then the collection electrode potential switching mechanism 21 is moved to the collection electrode 9 by the control of the control unit 25. The supplied voltage is switched to a positive discharge voltage, and the potential of the collecting electrode 9 is inverted. The charged particles collected on the insulator surface of the collecting electrode 9 are attracted to the counter electrode by Coulomb force (see FIG. 3). The charged particles fly toward the counter electrode 11, and the charged particles that have reached the counter electrode 11 release the electric charge on the counter electrode 11. Here, in order to shorten the time for the charged particles to reach the counter electrode 11, the voltage between the electrodes 9 and 11 may be increased stepwise (step) or in proportion to time (lamp). Thereby, the total measurement time is shortened.

The central processing unit 27 obtains the number of particles by obtaining the number of times the current has flowed through the counter electrode 9 based on the detection signal from the current detector 23 input via the analog signal input unit 33.
Further, the central processing unit 27 obtains the particle flight time from the collection electrode 9 to the counter electrode 11 for each particle detected by the current detector 23 based on the time information from the timer 29. Since the flight time of the charged particles is determined by the number of charges of the particles and the particle size, the particle size can be calculated from this flight time.

The flight time and particle size of the particles can be calculated by the following formulas (1) to (6).
In equations (1) to (6), t is the particle flight time, l is the distance between the electrodes, Zp is the electric mobility, V is the applied voltage between the electrodes, N is the number of charges, e is the elementary charge, and Cc is the Cunningham correction. Coefficient, π is the circumference, μ is the viscosity coefficient, Dp is the particle size, μr is the reference viscosity coefficient, Trμ is the viscosity coefficient reference temperature, Sμ is the viscosity coefficient reference Sutherland number, T is the temperature, Kn is the Knudsen number, αc, βc and γc are constants, λ is an average free process, λγ is a reference average free process, Pγλ is an average free process reference pressure, P is a pressure, Tγλ is an average free process reference temperature, and Sλ is an average free process reference Sutherland number.

For example, when the distance between the electrodes 9 and 11 is 1 mm (millimeter), a monovalent particle of 1 μm (micrometer) has a voltage between the electrodes 9 and 11 of 1666 V (volts) and 1 of 100 nm (nanometers). Valent particles are 111 V, 10 nm particles are 10/7 V, and the flight time between the electrodes 9 and 11 is 1 second.
As described above, the embodiment described with reference to FIGS. 1 to 3 can measure the number of particles and the particle size of the particles contained in the sample gas without using the sheath gas flow.

FIG. 4 is a schematic configuration diagram for explaining another embodiment. In FIG. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
This embodiment further includes a heater (heating mechanism) 35 for heating the collection electrode 9 as compared with the embodiment described with reference to FIG. The operation of the heater 35 is controlled by the control unit 25.

The operation of this embodiment will be described.
The charged particles contained in the sample gas are collected on the collection electrode 9 in the same manner as the collection operation described with reference to FIG. At the time of collecting the charged particles, the collecting electrode 9 may be heated by the heater 35 or may not be heated.
In the same manner as the desorption operation described with reference to FIG. 3, the potential of the collection electrode 9 is set to fly the charged particles collected on the insulator surface of the collection electrode 9 toward the counter electrode 11. Invert. At this time, the collection electrode 9 is heated to a predetermined temperature by the heater 35. By heating the collecting electrode 9, the charged particles collected on the insulator surface of the collecting electrode 9 vibrate, and the charged particles are easily separated from the collecting electrode 9.
Thereafter, in the same manner as the detection operation of the embodiment described with reference to FIGS. 1 to 3, the number of particles and the particle size of the particles contained in the sample gas are measured.

In the embodiment described with reference to FIG. 4, the collecting electrode 9 is heated by the heater 35 to vibrate the collected charged particles, but instead of the heater 35, the collecting electrode 9 is vibrated. A vibrating mechanism may be used.
For example, the collection electrode 9 is vibrated by a vibrator using a piezo element. The operation of the vibration mechanism is controlled by the control unit 25, and at the time of collecting charged particles, the collection electrode 9 may be vibrated by the vibration mechanism or may not be vibrated. However, at least when the potential of the collection electrode 9 is reversed in order to fly the charged particles collected by the collection electrode 9 to the counter electrode 11 side, the collection electrode 9 is vibrated by a vibration mechanism. As a result, the collected charged particles are vibrated. Thereby, the charged particles are easily separated from the collecting electrode 9.

FIG. 5 is a schematic configuration diagram for explaining still another embodiment. In FIG. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
In this embodiment, compared with the embodiment described with reference to FIG. 1, light containing light having a wavelength capable of imparting energy to the charged particles collected by the collecting electrode 9 is supplied to the collecting electrode 9. A light excitation mechanism 37 for irradiating is further provided. The operation of the light excitation mechanism 37 is controlled by the control unit 25.

The light excitation mechanism 37 includes, for example, a lamp, a laser, or a bandpass filter for irradiating light of a specific wavelength.
At the time of collecting charged particles, the light excitation mechanism 37 may or may not irradiate the insulator surface of the collecting electrode 9 with light of a specific wavelength. However, at least when the electric potential of the collecting electrode 9 is reversed so that the charged particles collected by the collecting electrode 9 fly to the counter electrode 11 side, the light excitation mechanism 37 captures light of a specific wavelength. The charged particles collected by the collecting electrode 9 are irradiated to selectively excite and vibrate only charged particles having a specific chemical structure that absorbs light of a specific wavelength. As a result, the charged particles having a specific chemical structure can be easily separated from the collecting electrode 9, and only the charged particles having the specific chemical structure can fly toward the counter electrode 11. The chemical structure involved can be identified.

  In the embodiment described with reference to FIG. 5, the light excitation mechanism 37 that emits light of a specific wavelength is used. The light excitation mechanism 37 imparts energy to the charged particles collected by the collection electrode. Any light source and optical system may be used as long as it has a function capable of irradiating light including light having a wavelength that can be generated. In this case, all the charged particles collected by the collection electrode 9 are excited and vibrated, and are easily separated from the collection electrode 9.

  Moreover, you may use the optical heater for heating the collection electrode 9 by light irradiation instead of the photoexcitation mechanism for providing energy to the charged particle collected by the collection electrode. The operation of the light heater is controlled by the control unit 25, and when collecting charged particles, the collection electrode 9 may be heated by the light heater or may not be heated. However, at least when the potential of the collecting electrode 9 is reversed so that the charged particles collected by the collecting electrode 9 fly to the counter electrode 11 side, the collecting electrode 9 is heated by a light heater. As a result, the collected charged particles are vibrated. Thereby, the charged particles are easily separated from the collecting electrode 9.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and the dimensions, shapes, arrangements, and the like are examples, and are within the scope of the present invention described in the claims. Various changes can be made.

DESCRIPTION OF SYMBOLS 1 Sampling line 3 Charging apparatus 7 Flow-path restriction board 9 Collection electrode 11 Counter electrode 13 Sample gas supply port 15 Exhaust line 17 Flow control valve 19 Exhaust pump 21 Collection electrode electric potential switching mechanism 23 Current detector 25 Control part 27 Central processing unit 29 Timer 35 Heater (heating mechanism)
37 Photoexcitation mechanism

Claims (12)

A charging mechanism for charging particles contained in the sample gas;
At least a portion in contact with the sample gas is covered with an insulator, and a collection electrode for collecting particles charged by the charging mechanism on the insulator surface;
A sample gas introduction mechanism for flowing the sample gas that has passed through the charging mechanism to the insulator surface of the collecting electrode;
A collecting electrode potential switching mechanism for switching and applying a collecting voltage and a discharging voltage to the collecting electrode;
The collection electrode is a counter electrode arranged to face the collection electrode at a predetermined interval;
A current detector for detecting particles by detecting a current flowing through the counter electrode due to adhesion of charged particles emitted from the collecting electrode;
A time-of-flight measuring unit that obtains a time of flight of particles from the collection electrode to the counter electrode for each particle detected by the current detector.   The sample gas introduction mechanism has a size smaller than the distance between the collection electrode and the counter electrode, and a sample is supplied from a sample gas supply port disposed near the collection electrode rather than the counter electrode. The particle measuring apparatus according to claim 1, wherein a gas is allowed to flow on the insulator surface of the collecting electrode.   The particle measuring apparatus according to claim 1, wherein the sample gas introduction mechanism causes the sample gas to flow along the longitudinal direction of the insulator surface of the collecting electrode.   4. The particle according to claim 1, wherein the sample gas introduction mechanism causes the sample gas to flow at an angle with respect to the insulator surface so as to face the insulator surface of the collection electrode. measuring device.   The sample gas introduction mechanism has a size smaller than the distance between the collection electrode and the counter electrode, and a sample is supplied from a sample gas supply port disposed near the collection electrode rather than the counter electrode. The particle measuring apparatus according to claim 1, wherein a gas is allowed to flow on the insulator surface of the collecting electrode.   The particle measuring apparatus according to claim 1, wherein the sample gas introduction mechanism causes the sample gas to flow along the longitudinal direction of the insulator surface of the collecting electrode.   4. The particle according to claim 1, wherein the sample gas introduction mechanism causes the sample gas to flow at an angle with respect to the insulator surface so as to face the insulator surface of the collection electrode. measuring device.   The particle | grain measuring apparatus as described in any one of Claim 1 to 7 further equipped with the heating mechanism which heats the said electrode for collection.   The particle | grain measuring apparatus as described in any one of Claim 1 to 7 further equipped with the vibration mechanism which vibrates the said electrode for collection.   The particle measuring apparatus according to any one of claims 1 to 7, further comprising a photoexcitation mechanism for imparting energy to the charged particles collected by the collecting electrode.   The particle measurement apparatus according to claim 10, wherein the light excitation mechanism includes a lamp, a laser, or a bandpass filter for irradiating light of a specific wavelength.   The particle | grain measuring apparatus of Claim 11 which specifies the chemical structure contained in the particle | grains excited based on the wavelength irradiated from the said optical excitation mechanism.

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