JP3790467B2 - Dry particle size analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dry particle size distribution measuring apparatus.
[0002]
[Prior art]
In a conventional dry particle size distribution measuring apparatus, a trough containing a granular sample is vibrated by a linear feeder having an electromagnet and a leaf spring so that the sample in the trough is removed from a sample dropping hole formed in the trough. There is a sample that is dropped and supplied to the lower flow cell.
[0003]
In the conventional dry particle size distribution measuring device, the conveyance efficiency is adjusted depending on the type, weight, viscosity, particle size, specific gravity, etc. (hereinafter referred to as type) of the granular sample to be measured. Further, the thickness of the leaf spring for converting the vertical vibration into the longitudinal vibration is adjusted. Further, in order to adjust the transport speed of the sample, the amplitude of the AC voltage with respect to the electromagnet is adjusted.
[0004]
[Problems to be solved by the invention]
However, the thickness of the leaf spring cannot be changed continuously, and may not be adjustable depending on the type of powder sample. In addition, AC voltage can be easily applied to the electromagnet when the frequency is a so-called commercial frequency of 50 Hz or 60 Hz. However, when applying other frequencies, a frequency converter is required and the configuration is complicated accordingly. And incurs a cost increase.
[0005]
The present invention has been made in consideration of the above-mentioned matters. The purpose of the present invention is to apply all the powder samples of different types to the flow cell with a predetermined quantitative property and stability corresponding to each sample. It is to provide a dry particle size distribution measuring apparatus that can be supplied.
[0006]
[Means for Solving the Problems]
To achieve the above object, the present invention is composed primarily of a linear feeder for vibrating the trough and trough for accommodating the sample, and, said linear feeder sample supply device including an electromagnet and a leaf spring And a measurement unit disposed below the sample supply device, and by vibrating the trough with a linear feeder, the sample in the trough is dropped from a sample dropping hole formed in the trough, and the sample is Scattered light and / or diffracted light generated when laser light is supplied to the flow cell provided in the measurement unit and the sample passing through the flow cell is detected by the light detection unit, and the detection output is calculated. input to the control unit, the dry particle size distribution measuring instrumentation that by performing a predetermined operation in the operation control unit and to obtain a particle size distribution of the sample In, applies a rectangular pulse voltage to the electromagnet, Les the sample passing through the flow cell - said flow cell in said arithmetic control unit on the basis of the amount of transmitted light obtained from the measuring unit when irradiated with laser light The flow state of the sample is detected, and the vibration of the trough is controlled based on the flow state (claim 1).
[0007]
In the dry particle size distribution measuring apparatus, it is preferable to detect the falling state of the sample and control the duty ratio, frequency, and amplitude of the rectangular pulse voltage applied to the electromagnet based on the detection result (claim). 2).
[0008]
In the dry particle size distribution measuring apparatus, since a rectangular pulse voltage is applied to the electromagnet in the linear feeder that vibrates the trough, a frequency converter is used unlike the case where an AC voltage is supplied to the electromagnet. There is no need, various rectangular pulse voltages can be arbitrarily applied, the configuration of voltage application is simple, and the control can be easily performed.
[0009]
And according to the said structure, although a leaf | plate spring was adjusted, a granular material may not be conveyed smoothly due to the characteristic of a granular material, or an assembly part in a linear feeder Even if adjustment unevenness due to variations occurs, only by controlling the duty ratio, frequency, amplitude in the rectangular pulse voltage, it is possible to obtain the conveyance characteristics according to the type of powder sample, etc. Even samples having different characteristics such as specific gravity, particle size, and viscosity can be supplied to the flow cell with a predetermined quantitative property and stability.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the details of the present invention will be described with reference to the drawings. 1 to 3 show one embodiment of the present invention. First, FIG. 1 schematically shows the overall configuration of a dry particle size distribution measuring apparatus according to the present invention. In this figure, 1 is a measuring unit, and 2 is a sample supply device provided above the measuring unit 1. is there.
[0011]
The measurement unit 1 is configured as follows, for example. That is, reference numeral 3 denotes a cylindrical flow cell provided in the vertical direction, and optical windows 3a and 3b are formed on opposite side surfaces thereof. Then, outside the one optical window 3a, a laser light source unit 6 for irradiating the sample 4 falling in the flow cell 3 with the laser light 5 is disposed so as to face the one optical window 3a. In addition, outside the other optical window 3b, a light detector 7 for receiving scattered light and / or diffracted light generated when the sample 4 is irradiated with the laser beam 5 faces the other optical window 3b. Are arranged to be.
[0012]
Reference numeral 8 denotes an ejector as a sample introduction portion provided above the flow cell 3, and includes a funnel-shaped portion 8a. A sample guide portion 9 connected to the flow cell 3 is continuously provided below the funnel-shaped portion 8a. A supply path 11 for compressed air 10 is connected to the ejector 8, and the compressed air 10 supplied by the compressed air supply path 11 is introduced into the sample guide section 9 on the lower surface side of the funnel-shaped portion 8 a. An air flow path 8b is formed, and compressed air 10a flowing through the air flow path 8b is sprayed as a dispersed flow on the sample 4 falling from a trough 18 (described later) of the sample supply device 2. . Further, the lower end of the sample guide portion 9 is inserted and connected to the flow cell 3, and the lower end portion thereof is provided with a partition portion 9a extending to the vicinity of the upper ends of the optical windows 3a and 3b. Further, 12 is a rectifying plate provided around the portion where the sample guide portion 9 is inserted and connected to the flow cell 3 so as to be parallel to the partition portion 9a, and the outside air 13 is sucked into the flow cell 2 by the sucked outside air 13. A sheath flow 14 is formed therein.
[0013]
Reference numeral 15 denotes a sample recovery channel formed on the lower end side of the flow cell 3 and includes a suction device 16. A hopper 17 is provided above the ejector 8 and guides the sample 4 falling from a trough 18 (described later) of the sample supply device 2 into the ejector 8.
[0014]
The configuration of the sample supply device 2 will be described with reference to FIGS. 2 and 3 as well. The sample supply device 2 includes a trough 18 that accommodates the granular sample 4, and a linear feeder 19 that vibrates the trough 18. Consists mainly of. The vibration of the linear feeder 19 is controlled by a signal from the controller 20.
[0015]
As shown in FIG. 3, the trough 18 includes a bottom portion 21 having an elongated isosceles trapezoidal shape in plan view, and a front plate portion erected perpendicularly to the bottom portion 21 on the short side (hereinafter referred to as the front end side). 22, an isosceles trapezoidal rear plate portion 23 that extends obliquely upward from the rear end portion of the bottom portion 21, and the front plate portion 22 and the rear plate at the end portion of the long side (hereinafter referred to as the rear end side). It consists of side plate parts 24 erected on both the left and right side parts of the bottom part 21 so as to connect the part 23, and is formed in a box shape in which the upper part of an elongated isosceles trapezoidal shape in plan view is opened. That is, the trough 18 has a tapered shape in plan view, and as understood from FIG. 2, the height of the front plate portion 22 is lower than the position of the rear portion top portion 23a of the rear plate portion 23, and the rear end side. Therefore, it is configured so that more samples 4 can be placed and accommodated. Reference numeral 25 denotes a sample dropping hole which is opened in the immediate vicinity of the front plate 22 side of the bottom 21 and is formed in a rectangular shape in plan view that is long in the left-right direction of the bottom 21. In addition, as a constituent material of the trough 18, in addition to having an appropriate mechanical strength, a material that does not adsorb the sample 4 and that does not have magnetism due to the relationship with the linear feeder 19 described later is preferable. Such materials include stainless steel and appropriate synthetic resins.
[0016]
The configuration of the linear feeder 19 will be described with reference to FIG. 2. Reference numeral 26 denotes a base, and a base 28 is horizontally held above it via a vibration isolating member 27 such as rubber. An electromagnet fixing unit 29 is provided on the upper surface of the base 28, and the electromagnet 30 is fixed. 31a and 31b are a pair of leaf springs provided at an appropriate interval, and are inclined parallel to each other and tilted backward (leftward in FIG. 2), with their lower ends on the side surfaces of the electromagnet fixing unit 29. A plate-like suction drive member 32 whose upper and lower surfaces are parallel to each other is held in a horizontal state at their upper ends. The adsorption drive member 32 is made of a material that is adsorbed by a magnetic force such as iron. It is provided in the formed state. The pair of leaf springs 31a and 31b convert the vibration in the vertical direction into the vibration in the front-rear direction, and the pushing force of one (rear end side) leaf spring 31b is the other (front end side) leaf spring 31a. It is configured to be stronger than that. In the trough 18, the bottom 21 is horizontal when the electromagnet 30 is not energized at all times.
[0017]
The controller 20 controls the linear feeder 19 and the suction device 16 based on a command from the arithmetic control unit 33 described later. In this embodiment, in particular, for the electromagnet 30 in the linear feeder 19. A rectangular pulse voltage as shown in FIG. 4 is arbitrarily applied. In FIG. 4, A is the pulse duration, B is the pulse separation, and A / B is the pulse duty ratio. C is the amplitude of the pulse and represents the magnitude of the voltage.
[0018]
Referring again to FIG. 1, reference numeral 33 denotes a calculation control unit, which comprises a personal computer, for example, and controls the entire apparatus, and uses calculation formulas based on the Franhofer analysis theory and the Mie scattering theory based on the output signal from the measurement unit 1. The particle size distribution is calculated to obtain the particle size distribution in the sample 4, and the calculation result is displayed on the display 33a, or the memory unit provided inside or a memory card or memory disk that is detachably attached. Has the function of storing. In addition, the calculation control unit 33 can obtain the dropped amount of the sample supplied to the flow cell 3 based on the transmitted light amount obtained from the measurement unit 1.
[0019]
In the dry particle size distribution measuring apparatus, the reference particles are used as the sample 4, the spring thicknesses of the leaf springs 31a and 31b are adjusted in the reference particles, and the reference particles are adjusted to move toward the front end portion in the trough 18. To do. Then, for example, a rectangular pulse voltage such as a minimum of 0 V and a maximum of hours V is applied to the coil of the electromagnet 30. As a result, the attracting drive member 32 is intermittently attracted to the electromagnet at a constant cycle, so that the mass of the electromagnet 30 and the base 28 is applied as a reaction force, so that the trough 18 is vibrated upward and forward. It is possible to move the sample 4 placed and accommodated in 18 toward the front end of the trough 18 and drop it from the sample dropping hole 25.
[0020]
The particulate sample 4 dropped from the sample dropping hole 25 enters the flow cell 3 through the hopper 17, the ejector 8, and the sample guide portion 9, and is irradiated with the laser beam 5 when passing through the flow cell 3. The scattered light and diffracted light generated at this time are detected by the light detection unit 7, and the output at that time is input to the calculation control unit 33, whereby the particle size distribution of the powder sample 4 is obtained. Further, the arithmetic control unit 33 can obtain the dropped amount of the sample 4 supplied to the flow cell 3 based on the transmitted light amount obtained from the measuring unit 1.
[0021]
By the way, the granular material sample 4 has what has various characteristics, and may not be smoothly conveyed by the trough 18 like a standard particle. In that case, the vibration of the trough 18 is adjusted based on the state of the flow in the flow cell 3 when the granular sample 4 is dropped. That is, as understood from the above description, the trough 18 vibrates by the attraction operation by the electromagnet 30, so that the duty ratio A / B, frequency, and amplitude in the rectangular pulse voltage supplied to the electromagnet 30 are as follows. C is controlled to be an appropriate value. As described above, by appropriately adjusting the rectangular pulse voltage supplied to the electromagnet 30, it is possible to obtain the conveyance characteristics according to the type of the granular material sample and the like. As a result of being transported above, the granular material sample 4 can be dropped and supplied to the flow cell 3 with a predetermined quantitative property and stability.
[0022]
【The invention's effect】
As described above, the present invention mainly comprises a trough that contains a sample and a linear feeder for vibrating the trough, and the linear feeder includes an electromagnet and a leaf spring , The measurement unit is arranged below the sample supply device, and the trough is vibrated by a linear feeder so that the sample in the trough is dropped from a sample dropping hole formed in the trough, and the sample is measured. is supplied to the flow cell provided in the part, les the sample passing through the flow cell - scattered light and / or diffracted light generated upon irradiation of laser light detected in the light detection unit, the arithmetic and control the detection output Fill in part, to a dry particle size distribution measuring apparatus to obtain a particle size distribution of the sample by performing a predetermined calculation in the arithmetic and control unit There are, applies a rectangular pulse voltage to the electromagnet, Les the sample passing through the flow cell - said flow cell in said arithmetic control unit on the basis of the amount of transmitted light obtained from the measuring unit when irradiated with laser light The flow state of the sample is detected, and the vibration of the trough is controlled based on the flow state .
Therefore, various rectangular pulse voltages can be applied as compared with the case where an AC voltage is supplied to the electromagnet.
[0023]
And according to the said structure, although a leaf | plate spring was adjusted, a granular material may not be conveyed smoothly due to the characteristic of a granular material, or an assembly part in a linear feeder Even if adjustment unevenness due to variations occurs, only by controlling the duty ratio, frequency, amplitude in the rectangular pulse voltage, it is possible to obtain the conveyance characteristics according to the type of powder sample, etc. Even samples having different characteristics such as specific gravity, particle size, and viscosity can be supplied to the flow cell with a predetermined quantitative property and stability.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing the overall configuration of a dry particle size distribution measuring apparatus according to the present invention.
FIG. 2 is a side view showing an example of a sample supply device in the dry particle size distribution measuring apparatus.
FIG. 3 is a perspective view showing an example of a trough in the sample supply device.
FIG. 4 is a diagram illustrating an example of a rectangular pulse voltage supplied to an electromagnet in the sample supply device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Measuring part, 2 ... Sample supply apparatus, 3 ... Flow cell, 4 ... Sample, 7 ... Photo detector, 18 ... Trough, 19 ... Linear feeder, 25 ... Sample drop hole, 30 ... Electromagnet, 31a, 31b ... Leaf spring , 33 ... arithmetic control unit .

Claims (2)

A sample supply device mainly composed of a trough containing a sample and a linear feeder for vibrating the trough, and the linear feeder is provided with an electromagnet and a leaf spring, and is disposed below the sample supply device Comprising a measurement unit, by vibrating the trough with a linear feeder, the sample in the trough is dropped from a sample dropping hole formed in the trough, and the sample is supplied to a flow cell provided in the measurement unit , Scattered light and / or diffracted light generated when the sample passing through the flow cell is irradiated with laser light is detected by the light detection unit, and the detection output is input to the calculation control unit. in a dry particle size distribution measuring apparatus to obtain a particle size distribution of the sample by performing a predetermined calculation, rectangular pulse to the electromagnet Applies a pressure, Le to the sample passing through the flow cell - detecting a state of the flow of the sample in the flow cell in the arithmetic control unit on the basis of the amount of transmitted light obtained from the measuring unit when irradiated with laser light The dry particle size distribution measuring apparatus is characterized in that the trough vibration is controlled based on the flow state .   2. The dry particle size distribution measuring apparatus according to claim 1, wherein the falling state of the sample is detected, and the duty ratio, frequency and amplitude of the rectangular pulse voltage applied to the electromagnet are controlled based on the detection result.

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