WO2004023109A1

WO2004023109A1 - Method and apparatus for measuring particle diameter distribution of powder

Info

Publication number: WO2004023109A1
Application number: PCT/JP2003/011250
Authority: WO
Inventors: Keiji Takahata; Kensei Ehara
Original assignee: National Institute Of Advanced Industrial Science And Technology
Priority date: 2002-09-04
Filing date: 2003-09-03
Publication date: 2004-03-18
Also published as: AU2003261907A1; JP3991099B2; JP2004093515A

Abstract

A method for measuring the particle diameter distribution of a powder, which comprises suspending a powder prone to agglomeration in a supercritical fluid to form a supercritical suspension fluid, releasing the fluid under such a condition to vaporize the fluid to prepare an aerosol in which the powder prone to agglomeration is dispersed in a gas formed by vaporizing the supercritical fluid from the supercritical suspension fluid, and measuring the particle diameter distribution of aerosol particles in the aerosol; and an apparatus for practicing the method. The method allows highly precise measurement of the particle diameter distribution of a powder prone to agglomeration, through the measurement of the particle diameter distribution of the above novel aerosol particles.

Description

Description Method for measuring particle size distribution of powder and its apparatus

The present invention relates to a method and apparatus for measuring a particle size distribution of a powder. Background art

One of the key factors in material development is the characteristics of the raw material powder. The most fundamental factor regarding the properties of the powder is the size of the particles. For example, an image analysis method using an electron microscope is known as a method for measuring the particle size distribution of a powder. However, this method disintegrates and disperses the powder completely into primary particles, and furthermore, it is difficult to obtain a statistically reliable sample number, and the obtained data is unreliable.

In general, powders of several microns or less show high cohesion irrespective of the material, and under normal environmental conditions, a plurality of primary particles aggregate to form higher-order aggregates. Normal. Therefore, in various particle size distribution measurement methods, the powder behaves not as primary particles but as a group of particles, and the obtained particle size distribution loses the characteristics of the particle size distribution of the primary particles. A very prominent particle size distribution of the group may result.

On the other hand, the light scattering method using a light scattering type particle counter (JIS B9921 light scattering type automatic particle counter) used in the field of aerosol, a differential electric mobility analyzer (DMA) (E. 0. Knutson and K T. After particle size selection by Whitby, Journal of Aerosol Science, 6 (1975) 443-452. The electric mobility method based on the combined use of DMA / CNC is widely used as an accurate particle size distribution measurement method. The light scattering method using a light scattering type particle counter irradiates aerosol particles with light, From the distribution state, the particle size distribution is measured. The electric mobility method based on the combination of DMA / CNC selects only aerosol particles having a specific narrow range of electric mobility using the classification device, DMA, and then uses the counting device, CNC, to perform classification. Vapors such as alcohol are condensed using particles as nuclei, aerosol particles are counted by an optical method, and the particle size distribution is measured.

However, as described above, conventional aerosol particles behave as a particle group because it is difficult to obtain primary aerosol particles, and the obtained particle size distribution loses the characteristics of the particle size distribution of primary particles. As a result, the particle population had a very broad particle size distribution, and sufficient measurement results could not always be obtained.

In order to measure the particle size distribution in a state where the powder sample is not sufficiently dispersed, it is not sufficient from the viewpoint of reliability and reproducibility in the evening, and the cohesive powder is dispersed well in the gas phase. It is thought that if aerosol particles can be obtained, it will be possible to measure the particle size distribution of the cohesive powder to a satisfactory extent, and the establishment of technology to obtain aerosol particles in the primary particle state as much as possible has become an important issue. Disclosure of the invention

The problem to be solved by the present invention is to provide a highly accurate particle size distribution of agglomerated powder by measuring the particle size distribution of the aerosol particles as aerosol particles in which the agglomerated powder is well dispersed in the gas phase. It is to provide a measuring method of.

Means for Solving the Problems The present inventors diligently studied the above problem and obtained the following findings to complete the present invention.

When the cohesive powder is suspended in a supercritical fluid, the cause of the cohesive force is removed by contact with the supercritical fluid, or the degree of cohesiveness is greatly reduced, and the cohesiveness is reduced. When the powder is disintegrated and the supercritical suspension fluid is released under environmental conditions that evaporate the supercritical fluid, a large expansion force can be obtained when the state changes, and it is generated with the state change Against a cohesive powder using a large expansion force It has been found that it is possible to develop a method for obtaining aerosol particles which can be disintegrated and rapidly become primary particles or further disintegrated and finely divided depending on the degree of expansion, and which are in a well-dispersed state.

A conventionally known method of measuring aerosol particles is applied to the aerosol particles thus obtained. That is, by applying a known measurement method of aerosol particles to the aerosol particles obtained by the method for producing novel aerosol particles, the aerosol particles obtained by the aerosol particle production method are actually primary particles or close to primary particles. Thus, aerosol particles in a good dispersion state can be obtained, and the particle size distribution of primary particles forming an aggregate or a state close to the primary particles can be measured. For such a measurement method, a method for measuring the particle size distribution of dispersed aerosol particles in a dispersed state, such as a light scattering method using a light scattering type particle counter or an electric mobility method using a combination of DMA / CNC, should be used. Can be.

According to the present invention, the following inventions are provided.

(1) The supercritical fluid, which is formed by suspending the cohesive powder in the supercritical fluid, is released under environmental conditions that evaporate the supercritical fluid. A method for measuring a particle size distribution of a powder, comprising measuring a particle size distribution of aerosol particles in a state where a cohesive powder is generated and dispersed in a vaporized gas.

(2) The method described in (1), characterized in that aerosol particles are generated and dispersed in a gas obtained by evaporating a supercritical fluid from a supercritical suspension fluid, stored, taken out, and the particle size distribution of the aerosol particles is measured. ) The method for measuring the particle size distribution of powder described in the above.

(3) The method for measuring the particle size distribution of a powder according to the above (1) or (2), wherein the generation and dispersion of the aerosol particles is carried out by spraying or impinging.

(4) The powder as described in (1), (2) or (3) above, wherein a dilution gas is supplied to the aerosol particles, the obtained aerosol particle concentration is controlled, and the particle size distribution is measured. Particle size distribution measurement method.

(5) The supercritical suspension fluid formed by suspending the cohesive powder in the supercritical fluid is The supercritical fluid is released under the environmental conditions that evaporate, and the aerosol particles in a state in which a cohesive powder is generated and dispersed in a gas in which the supercritical fluid is vaporized from the supercritical suspension fluid are irradiated with light, The method for measuring the particle size distribution of powder according to the above (1), (2), (3) or (4), wherein the particle size distribution is measured from the obtained scattered light by a light scattering method.

(6) The supercritical fluid, which is formed by suspending the cohesive powder in the supercritical fluid, is released under environmental conditions that evaporate the supercritical fluid, and the supercritical fluid is converted from the supercritical fluid. Aerosol particles in a state in which a cohesive powder is generated and dispersed in a vaporized gas are classified into only particles having a specific electric mobility, and subsequently, the vapors such as alcohol are condensed using the classified particles as nuclei. The particle size of the powder according to (1), (2), (3) or (4), wherein the particles are counted by an optical method, and the particle size distribution is measured by an electric mobility method. Distribution measurement method.

(7) Suspending the coagulable powder in the supercritical fluid, comprising: a supply means for supplying the supercritical fluid, a supply means for supplying the coagulable powder, and a discharge means for discharging the formed supercritical suspension fluid. The supercritical suspension fluid formation tank to be turbidized, and the supercritical suspension fluid discharged from the supercritical suspension fluid formation tank are released under the environmental conditions where the supercritical fluid is vaporized. Aerosol particle generating and dispersing means for generating and dispersing aerosol particles in a state where the cohesive powder is dispersed, and aerosol particles generating and dispersing the cohesive powder in a gas obtained by evaporating a supercritical fluid from a supercritical suspension fluid An apparatus for measuring the particle size distribution of powder, comprising: means for measuring the particle size distribution of powder.

(8) An aerosol particle generation and dispersion tank for generating and dispersing and storing aerosol particles in a gas obtained by evaporating a supercritical fluid from a supercritical suspension fluid, and subsequently, an aerosol particle provided with a means for extracting aerosol particles. The powder particle size distribution measuring device according to the above (7), wherein the particle size distribution is measured.

(9) The method according to (7) or (8), wherein the particle size distribution of aerosol particles provided with means for generating and dispersing aerosol particles, such as a spray nozzle or an impactor, is measured. An apparatus for measuring the particle size distribution of the powder described in the above. (10) The method according to the above (7), wherein the particle size distribution of the air port sol particles provided with a diluting gas supply means for controlling the generation concentration of the aerosol particles is measured.

(8) or the apparatus for measuring the particle size distribution of powder according to (9).

(11) Supercritical fluid forming tank for suspending coagulable powder in supercritical fluid, and supercritical fluid vaporizing supercritical suspending fluid discharged from supercritical suspending fluid forming tank Aerosol particle generating and dispersing means for generating and dispersing aerosol particles in a state in which cohesive powder is dispersed in a vaporized supercritical fluid, and evaporating a supercritical fluid from a supercritical suspended fluid (7) The method according to the above (7), further comprising: irradiating light to the sol particles of the aerosol in which the cohesive powder is generated and dispersed in the gas, and measuring the particle size distribution from the obtained scattered light by a light scattering method. (8), (9) or (10).

(12) The supercritical fluid forms a supercritical suspension fluid for suspending the cohesive powder in the supercritical fluid, and the supercritical fluid vaporizes the supercritical suspension fluid discharged from the supercritical suspension fluid formation tank. Aerosol particle generating and dispersing means for generating and dispersing aerosol particles in a state where cohesive powder is dispersed in a vaporized supercritical fluid, and supercritical fluid being vaporized from a supercritical suspended fluid Aerosol particles in which a cohesive powder is generated and dispersed in a gas that has been classified are classified into particles having a specific electric mobility only, and then the vapors such as alcohol are condensed using the classified particles as nuclei, The method according to the above (7), (8), (9) or (10), comprising means for counting particles by an optical method and measuring the particle size distribution by an electric mobility method. Body particle size distribution measuring device. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of a powder particle size distribution measuring device of the present invention.

FIG. 2 is a schematic view of another powder particle size distribution measuring device of the present invention.

Fig. 3 shows the appearance of glass particles observed with an optical microscope.

Fig. 4 shows the appearance of polymethyl methacrylate particles observed with an optical microscope. O

3 (a) and 3 (b) show aggregates at the time of supply, and (b) shows primary particles after generation and dispersion. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings. The apparatus shown in FIG. 1 is configured as follows.

A supercritical suspension fluid forming tank 1 for suspending the cohesive powder in a supercritical fluid to form a supercritical suspension fluid, and aerosol particles generation for obtaining aerosol particles connected thereto. It comprises a dispersing means 8 and a particle size distribution measuring means 14 for measuring the particle size distribution of the aerosol particles.

In order to form a supercritical suspension fluid by suspending the cohesive powder in the supercritical fluid, the supercritical suspension fluid forming tank 1 is provided with a supply means for supplying the supercritical fluid via the flow rate adjusting means 5. 4. It has a supply means 3 for supplying the cohesive powder and a discharge means 6 for discharging the formed supercritical suspension fluid.

In addition, aerosol particles are generated by releasing a supercritical fluid under environmental conditions to vaporize and forming aerosol particles from a supercritical suspension fluid in a gas in which the supercritical fluid is vaporized. The dispersing means 8 supplies the supercritical fluid discharged from the supercritical suspending fluid forming tank 1 via the flow rate adjusting means 7 to the supercritical fluid under the environmental conditions in which the supercritical fluid is vaporized. The aerosol particles are generated with the cohesive powder dispersed in the released and vaporized supercritical fluid.

Further, the generation and dispersion means 8 may be configured to include a generation and dispersion means such as a spray nozzle or an impact nozzle. The spray nozzle sprays the supercritical suspension fluid as fine mist, and in the case of impact, the fluid through the spray nozzle collides with a flat plate and bends the direction of the flow, so that crushing and It removes aggregates remaining without being converted into primary particles, and as a result, provides good aerosol particle Generation dispersion is possible.

Further, in the generation / dispersion means 8, for example, when it is necessary to adjust the concentration of the obtained aerosol particles, a dilution gas can be supplied as needed. Using a two-fluid nozzle equipped with a diluting gas supply means in the generating and dispersing means 8, the diluting gas from which impurities were removed by the diluting gas supply means at the gas fill rate was controlled at a flow rate controlled by the flow rate adjusting means. The aerosol particles that are supplied to the two-fluid nozzle and thus generated and dispersed are diluted according to the amount of the supplied diluting gas, and as a result, it is possible to obtain air-mouth sol particles having a controlled concentration.

The aerosol particles in a state where the agglomerated powder is generated and dispersed are flown into the particle size distribution measuring means 14 as a sample gas together with the gas obtained by evaporating the supercritical fluid, and the particle size distribution is measured.

The device in FIG. 2 is configured as follows.

Supercritical suspension fluid forming tank 1 which is the same as that in Fig. 1 above, connected to this, air port sol particle generation / dispersion tank 9 for generating air port sol particles, and aerosol particle supply for taking out air port sol particles Means 13 are comprised.

In the aerosol particle generation and dispersion tank 9, a supercritical suspension fluid obtained by suspending the cohesive powder in a supercritical fluid is released under environmental conditions that evaporate the supercritical fluid, and Aerosol particles are formed in a gas obtained by evaporating a supercritical fluid. The aerosol particle generation / dispersion tank 9 has a generation / dispersion means 8 for supplying the formed supercritical suspension fluid and generating / dispersing the sol particles at the air port, and a discharge means 11 for discharging the aerosol particles.

The aerosol particles are supplied to the aerosol particle supply means 13 for taking out the aerosol particles via the flow rate adjusting means 12 following the discharge means 11 for discharging the aerosol particles, and are taken out.

Further, the generation and dispersion means 8 may be configured to include a generation and dispersion means such as a spray nozzle or an impact nozzle. Spray nozzles are used for supercritical fluid suspension Sprayed as fine mist, and furthermore, the impact was reduced by colliding the fluid through the spray nozzle against a flat plate and bending the direction of the flow, resulting in agglomerates remaining without crushing or primary particles with sufficient inertia As a result, good generation and dispersion of aerosol particles can be achieved.

In the aerosol particle generation / dispersion tank 9, for example, when it is necessary to adjust the concentration of the obtained aerosol particles, a dilution gas can be supplied as needed. The diluent gas, from which impurities have been removed by the gas filter, is supplied to the aerosol particle generation / dispersion tank 9 at a flow rate controlled by the flow rate adjusting means. Accordingly, the aerosol particles generated and dispersed are diluted according to the amount of the supplied diluting gas, and as a result, aerosol particles having a controlled concentration can be obtained. Also, the generation concentration of aerosol particles can be controlled in the same manner by using a two-fluid nozzle provided with a dilution gas supply means in the generation / dispersion means 8.

In order to form a supercritical suspension fluid by suspending the cohesive powder in the supercritical fluid, the supercritical suspension fluid forming tank 1 is as follows.

The supercritical fluid can be appropriately selected and used. Specific examples include carbon dioxide, nitrous oxide, ethane, propane, ethylene, chlorofluorocarbon alternative, and water.

The purified carbon dioxide, ethane, ethylene, alternative chlorofluorocarbon, etc., is heated and pressurized to a critical state, and is converted into a supercritical fluid by the supercritical fluid supply means 4 and the flow control means 5 by the supercritical fluid supply means 4. It is supplied to the critical fluid suspension formation tank 1.

Further, in the supercritical suspension fluid forming tank 1, for example, a high-speed mixer using a stirring blade or a stirrer, or a suspension mixed with stirring by using and installing an ultrasonic generator. A turbid fluid can also be obtained.

The contact with the supercritical fluid due to the suspension removes the cause of the cohesive force on the powder, or the degree of cohesion is greatly reduced, and the cohesive powder is broken. The cohesive powder to be subjected to the particle size distribution measurement is supplied to the supercritical fluid forming tank 1 by the cohesive powder supply means 3. Examples of the cohesive powder include styrene, acrylate, methyl acrylate, and other polymers or copolymers obtained from vinyl monomers, and epoxy resins, phenol resins, melanin resins, polyamide resins, and silicone resins. And organic substances such as particles of various polymers or copolymers, and inorganic substances such as particles of various metals, nonmetals, and ceramics. As the cohesive powder, various substances can be used without specific restrictions or limitations depending on the constituent raw materials, shapes, and the like.

The supercritical fluid supply means 4 is provided with a flow rate adjusting means 5. Further, the supercritical suspension fluid forming tank 1 has a temperature control jacket 2 around it so that the supercritical fluid can be kept in a supercritical state or a subsupercritical state.

The supercritical fluid is a supercritical fluid that means a fluid in a supercritical state, and a supercritical state is a supercritical state that exceeds a critical temperature and a critical pressure, as well as a critical temperature and a critical pressure. Although the state is slightly lower than the above, the state change occurs in a very short time, and includes the subcritical state that can be handled almost in the same way as the above supercritical fluid. Subcritical fluid.

When carbon dioxide is used as the supercritical fluid, the temperature is 30 to 80 ° C, preferably 30 to 50 ° C, and the pressure is 40 to 400 atm, preferably 100 to 100 atm. It needs to be maintained at ~ 300 atm.

The supercritical fluid, which is formed by suspending a cohesive powder in a supercritical fluid, is released under environmental conditions that vaporize the supercritical fluid, and the air port sol is dissolved in a gas in which the supercritical fluid is vaporized. Particles are generated and dispersed.

The supercritical suspension fluid obtained in the above step is discharged through the supercritical suspension fluid discharge means 6. The aerosol particles are generated and dispersed by an aerosol particle generation / dispersion means 8 formed by a nozzle, and supplied to an aerosol particle generation / dispersion tank 9. For nozzles, a nozzle formed by a single tube that sprays a supercritical suspension fluid, or if the concentration of aerosol particles obtained in addition to the supercritical suspension fluid needs to be adjusted, it is necessary. The two-fluid nozzle formed by the double pipe can be used.c This release allows the cohesive powder suspended in the supercritical fluid to The abrupt volume expansion of the supercritical fluid that has entered gaps causes the disintegration of the agglomerated powder, the formation of primary particles, or the further disintegration and refinement, resulting in the formation of aerosol particles in the vaporized gas of the supercritical fluid. It can be generated and dispersed as aerosol particles. A temperature control jacket 10 is provided around the aerosol particle generation / dispersion tank 9. The temperature control jacket 10 has only to have a temperature control function capable of compensating for a temperature change, and a material and a shape suitable for the function are selected and used.

The method of taking out the aerosol particles generated in the aerosol particle generation / dispersion tank 9 in the preceding step and supplying the aerosol particles and the aerosol particle supply means 13 are as follows.

The aerosol particles generated in the generated aerosol particle dispersion tank 9 are taken out and used as needed. The aerosol particles are discharged through the aerosol particle discharge means 11, the flow rate is adjusted by the flow rate adjustment means 12, and the aerosol particles are taken out from the aerosol particle supply means 13 and used.

As a result of releasing the supercritical suspension fluid formed by suspending the cohesive powder in the supercritical fluid obtained under the present invention under environmental conditions for vaporizing the supercritical fluid, the supercritical fluid is vaporized. The agglomerated powder can be crushed, turned into primary particles, or further crushed and refined in a mixed gas, so that aerosol particles can be obtained.

The obtained aerosol particles flow into the particle size distribution measuring means 14 as a sample gas together with the vaporized gas of the supercritical fluid, and the particle size distribution is measured. Particle size distribution measuring means 14 includes (1) a particle size distribution measuring method by a light scattering method using a light scattering type particle counter, and (2) a particle size distribution measuring method by an electric mobility method using a combination of DMA / CNC. The method for measuring the particle size distribution is adopted.

The light scattering method using a light scattering particle counter irradiates aerosol particles with light and measures the particle size distribution based on the distribution state of the scattered light. The sample gas containing aerosol particles is sucked and passed through the area irradiated by the stabilized light source. At this time, the light scattered forward or side by the individual aerosol particles is condensed on a photoelectric element such as a photomultiplier tube and converted into a pulsed electric signal. The peak value of the pulse signal is proportional to the amount of scattered light, and by utilizing the fact that the amount of scattered light and the particle size of the aerosol particles are in a fixed relationship, the particle size is selected and analyzed by analyzing the pulse peak value. The particle size distribution of the aerosol particles can be measured by counting the number of pulsated pulses.

In the electromobility method using a combination of DMA / CNC, only the aerosol particles having a specific narrow range of electric mobility are selected by a classification device, DMA, and the classified particles are then processed by a counting device, CNC. Vapors such as alcohol are condensed as nuclei, the number of aerosol particles is counted by an optical method, and the particle size distribution is measured. The sample gas containing aerosol particles is passed through an ion generation field caused by radiation or the like to give charges to the particles. These charged particles are introduced along the outer cylinder into the electric field formed by the double cylinder electrode of DMA, which is a classifier. On the other hand, clean gas containing no particles flows between the cylindrical electrodes in a rectified state. Positively and negatively charged particles or uncharged particles move in the direction of the electric field at their respective moving speeds, but also move in the axial direction, which is the direction of flow of the clean gas between the cylindrical electrodes. If a slit is provided at an arbitrary position on the inner cylindrical electrode and only the particles that reach the slit are taken out, those particles are only particles with a constant electric mobility, that is, particles with a uniform particle size. The particle size of the classified particles can be changed by adjusting the voltage applied to the cylindrical electrode. The classified particles are passed through supersaturated steam such as alcohol in the pipe of CNC which is a counting device, Vapors are condensed using particles as nuclei to increase the particle size, and the grown particles are irradiated with light, and the particles are counted from the scattered light. Aerosol particles can be classified by DMA and counted by CNC to measure the particle size distribution.

Hereinafter, the contents of the present invention will be described in more detail with reference to examples.

Example 1

A glass particle having an average particle diameter of 10 mg of primary particles is fed into the supercritical suspension fluid forming tank 1 from the cohesive powder supply means 3 and the temperature is 4 from the supercritical fluid supply means 4. Supercritical carbon dioxide at 0 ° C and a pressure of 100 atm was introduced and suspended. The glass particles at the time of feeding are high-order aggregates having a size of several tens to several hundreds / zm.

The suspension is discharged from the supercritical suspension fluid discharge means 6 through the flow rate control means 7 through the aerosol particle generation and dispersion means 8 comprising a spray nozzle having an equivalent orifice diameter of 0.13 mm, and the aerosol is discharged. Particles were generated and dispersed. By the light scattering type particle counter, glass particles that were high-order aggregates of several tens to several hundreds were generated as air-ported zeolite particles dispersed in highly concentrated primary particles. It was confirmed that it had an average particle size of m. Furthermore, glass particles generated and dispersed as aerosol particles were deposited on slide glass and observed with an optical microscope to confirm that they were dispersed to primary particles. FIG. 3 (a) shows the state of the aggregate of the glass particles at the time of supply as observed by an optical microscope, and FIG. 3 (b) shows the state of the glass particles generated and dispersed according to the present example. .

Example 2

In the same manner as in Example 1, polymethyl methacrylate particles in which 1 O mg of primary particles have an average particle size of about 1 zm are charged into the supercritical suspension fluid forming tank 1 from the cohesive powder supply means 3, Supercritical carbon dioxide having a temperature of 40 ° C. and a pressure of 100 atm was introduced from the supercritical fluid supply means 4 and suspended therein. At the time of supply, the polymethylmethacrylate particles are high-order aggregates of several tens to several hundreds of zm in size.

The suspension is discharged from the supercritical suspension fluid discharging means 6 via the flow rate adjusting means 7 to 0.1. Aerosol particles generated and dispersed by the aerosol particle generation / dispersion means 8 composed of a spray nozzle having an equivalent orifice diameter of 3 mm were generated and dispersed. Using a light scattering particle counter, polymethyl methyl acrylate particles, which were high-order aggregates of several tens to several hundreds of meters, were generated as aerosol particles dispersed in highly concentrated primary particles. It was confirmed that the particles had a mu average particle size of m. In addition, polymethyl methacrylate particles generated and dispersed as aerosol particles were deposited on slide glass, observed with an optical microscope, and confirmed to have been dispersed to primary particles. FIG. 4 (a) shows the state of aggregates of polymethyl methacrylate particles at the time of supply as observed by an optical microscope, and FIG. 4 (b) shows polymethyl methacrylate dispersed and generated according to the present example. The appearance of particles is shown.

Industrial applicability

As described above, the aerosol particles obtained by disintegrating and dispersing the cohesive powder in the gas phase by the method for measuring the particle size distribution of the powder according to the present invention are used in the field of aerosol. By using the particle size distribution measurement method, it is possible to measure the particle size distribution of a powder composed of aerosol particles with high accuracy.

Further, according to the powder particle size distribution measuring apparatus of the present invention, good aerosol particles obtained by disintegrating and dispersing a cohesive powder in a gas phase have a particle size used in the field of aerosol. By using the distribution measuring device, a highly accurate device for measuring the particle size distribution of powder composed of aerosol particles can be obtained.

Claims

The scope of the claims

1. Supercritical fluid, which is formed by suspending a cohesive powder in a supercritical fluid, is released under environmental conditions that evaporate the supercritical fluid. A method for measuring the particle size distribution of aerosol particles, wherein the particle size distribution of aerosol particles in a state in which a cohesive powder is generated and dispersed in a gasified gas.

2. The aerosol particles are generated and dispersed in a gas obtained by evaporating a supercritical fluid from a supercritical suspension fluid, stored, taken out, and the particle size distribution of the aerosol particles is measured. The method for measuring the particle size distribution of powder according to claim 1.

3. The method for measuring the particle size distribution of powder according to claim 1 or 2, wherein the generation and dispersion of aerosol particles is carried out by spraying or impact treatment.

4. The powder according to claim 1, 2 or 3, wherein a dilution gas is supplied to the aerosol particles, the concentration of the obtained aerosol particles is controlled, and the particle size distribution is measured. A method for measuring the particle size distribution of a body.

5. Release the supercritical suspension fluid formed by suspending the cohesive powder in the supercritical fluid under environmental conditions that vaporize the supercritical fluid, and evaporate the supercritical fluid from the supercritical suspension fluid. Irradiating light to the aerosol particles in a state in which the cohesive powder is generated and dispersed in the gasified gas, and measuring the particle size distribution from the obtained scattered light by a light scattering method. 4. The method for measuring a particle size distribution of a powder according to paragraph 1, paragraph 2, paragraph 3, or paragraph 4.

6. The supercritical fluid, which is formed by suspending the cohesive powder in the supercritical fluid, is released under environmental conditions that vaporize the supercritical fluid, and the supercritical fluid is vaporized from the supercritical fluid. Aerosol particles in a state in which cohesive powder is generated and dispersed in the gasified gas are classified into only particles having a specific electric mobility, followed by a vapor such as alcohol using the classified particles as nuclei. Wherein the particles are counted by an optical method and the particle size distribution is measured by an electric mobility method. A method for measuring the particle size distribution of a body.

7. Supply means for supplying a supercritical fluid, supply means for supplying a cohesive powder, and formation A supercritical suspending fluid forming tank for suspending the cohesive powder in the supercritical fluid, and a supercritical fluid discharged from the supercritical suspending fluid forming tank. An aerosol particle generating and dispersing means for releasing a suspension fluid under environmental conditions in which the supercritical fluid is vaporized, and generating and dispersing aerosol particles in a state where the cohesive powder is dispersed in the vaporized supercritical fluid. , And means for measuring the particle size distribution of aerosol particles in which a cohesive powder is generated and dispersed in a gas in which a supercritical fluid is vaporized from a supercritical suspension fluid. Diameter distribution measuring device.

8. Aerosol particle generating and dispersing tank for generating and dispersing and storing aerosol particles in a gas obtained by evaporating a supercritical fluid from a supercritical suspending fluid, and subsequently, aerosol particles provided with aerosol particle extracting means. 9. The powder particle size distribution measuring device according to claim 7, wherein the particle size distribution is measured.

9. Claims 7 or 8 characterized by measuring the particle size distribution of aerosol particles provided with a generating and dispersing means such as a spray nozzle or impactor for generating and dispersing aerosol particles. An apparatus for measuring the particle size distribution of the powder described in the above.

10. The particle size distribution of the aerosol particles provided with a diluting gas supply means for controlling the generation concentration of the aerosol particles is measured, wherein the particle size distribution of the aerosol particles is measured. Item 3. A powder particle size distribution measuring apparatus according to the above item.

1 1. Supercritical fluid formation tank for suspending coagulable powder in supercritical fluid, and supercritical fluid vaporizes supercritical suspension fluid discharged from supercritical suspension fluid formation tank Aerosol particle generation and dispersion means for generating and dispersing aerosol particles in a state where cohesive powder is dispersed in a vaporized supercritical fluid, and supercritical fluid is vaporized from supercritical suspension fluid Aerosol particles in which a coagulable powder is generated and dispersed in the gas, and a method for measuring the particle size distribution from the obtained scattered light by a light scattering method. An apparatus for measuring the particle size distribution of powder as described in paragraph 7, 8, 9, or 10.

12. Supercritical fluid forming tank for suspending cohesive powder in supercritical fluid The supercritical fluid discharged from the boundary suspension fluid formation tank is released under the environmental conditions in which the supercritical fluid vaporizes, and the aerosol is dispersed with the cohesive powder dispersed in the vaporized supercritical fluid. Aerosol particle generating and dispersing means for generating and dispersing particles, and only particles having a specific electric mobility of aerosol particles in which a cohesive powder is generated and dispersed in a gas obtained by evaporating a supercritical fluid from a supercritical suspending fluid It is characterized by comprising means for condensing vapors such as alcohol with the particles after classification as nuclei, counting the particles by an optical method, and measuring the particle size distribution by an electric mobility method. 10. The powder particle size distribution measuring device according to claim 7, wherein the particle size distribution of the powder is measured.