JP3422707B2 - Light scattering particle size distribution analyzer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scattering type particle size distribution measuring device. 2. Description of the Related Art Particle measurement techniques are used in a wide range of fields such as medicines, foods, ceramics, cosmetics, paints, and pigments.
It is indispensable in determining and evaluating the performance of powdered materials, and their importance is increasing day by day. As a device for measuring the particle size distribution of such particles, there is a light scattering type particle size distribution measuring device using a laser light source. FIG. 4 schematically shows a conventional structure of the above-mentioned light scattering type particle size distribution measuring apparatus.
Is a dispersion bath in which stirring blades 53 rotated by a motor 52 are provided.
An ultrasonic vibrator (ultrasonic oscillator) 56 that is vibrated by an oscillator (ultrasonic driver) 55 is provided outside the device, and the powder (or slurry) to be inputted and the dispersion for dispersing the powder (or slurry). A medium (for example, pure water or alcohol) is mixed and stirred to obtain a sample liquid. Reference numeral 57 denotes a flow cell, which is connected to the dispersion bus 1 by a circulation flow path 60 having a roller pump (peristal pump) 58 and a drain valve (switching valve) 59. The roller pump 58 has three rollers 58b driven to rotate counterclockwise by a motor shaft 58a,
It consists of a tube 58c and a body 58d and is used as a circulation pump. Then, the sample liquid is introduced into the flow cell 57, and in that state, laser light is supplied from the laser light source 61 provided on one side of the flow cell 57 to the flow cell 5.
7, the diffracted / scattered light at that time is detected by a photodetector 63 via a condenser lens 62 provided on the other side of the flow cell 57, and based on the diffracted / scattered light pattern obtained thereby. To obtain the particle size distribution of the particles in the sample liquid. Note that a measurement unit 64 is formed by the flow cell 57, the laser light source 61, the condenser lens 62, the photodetector 63, and the like. In addition, 65 is a drain passage, and 66 is a water level sensor. [0005] However, the apparatus having the above configuration has the following disadvantages. (1) Since the roller pump 58 is used as a circulation pump, the circulation flow rate of the sample liquid is small, and the tube 58c needs to be periodically replaced due to breakage or the like. (2) The ultrasonic transducer 56 is connected to the upper side 54 of the dispersion bath 51.
Therefore, ultrasonic waves cannot be applied to the sample liquid unless a large amount of the sample liquid is supplied to the dispersion bath 51. In other words, when the ultrasonic vibrator 56 is operated when the dispersion bath 51 is empty or a small amount of the sample liquid does not reach the upper side surface 54, the applied voltage sharply increases and breaks. It is necessary to supply the sample liquid up to the upper position of the upper side surface 54 so as to cover the attachment area of the child 56. As shown in FIG. 5, in a conventional light scattering type particle size distribution measuring apparatus using a centrifugal pump 67 as a circulating pump, an ultrasonic transducer 56 is connected to a dispersion bath 51.
, It is necessary to provide an outer frame 67 having a complicated structure connected to the distribution bus 51 in order to secure this mounting position. In FIG. 5, reference numeral 69 denotes a motor that rotationally drives the stirring blade 53 and the rotary blade 70 of the centrifugal pump 67. [0007] In the conventional light scattering type particle size distribution measuring apparatus shown in FIG.
Therefore, the sample liquid cannot be irradiated with ultrasonic waves unless a large amount of the sample liquid is supplied to the dispersion bath 51. Further, the drive shaft 67a of the centrifugal pump 67 is
Is mounted horizontally through the shaft insertion hole 72 provided in the cover body 71, the seal is required for the drive shaft 67a, and there is always a risk of liquid leakage. In FIG. 6, reference numeral 73 denotes a motor for the drive shaft 67a, and reference numeral 74 denotes an upper limit water level sensor. Further, in the conventional light scattering type particle size distribution measuring apparatus shown in FIG. 7, the driving shaft 67a of the centrifugal pump 67 is moved from above the upper opening 51a of the dispersion bus 51 to the centrifugal pump 6.
7 is mounted vertically vertically so as to be connected to the rotor 70 of the centrifugal pump 67 through the communication portion 73 with the centrifugal pump 7, and an ultrasonic actuator 74 of an expensive actuator type is used to apply ultrasonic waves to the sample liquid flowing through the circulation channel 60. Although it is irradiating,
Since the ultrasonic vibrator 74 is attached to another part of the circulation flow channel 60, the mechanism is complicated, and the ultrasonic vibrator 74 is more expensive than the other ultrasonic vibrators 56. In FIG. 7, reference numeral 75 denotes a motor for driving the drive shaft 67a via a transmission mechanism such as a pulley 76 and a belt 77. In addition, in the conventional mounting mechanism of the dispersion bus 51, the circulation pumps 58 and 67 and the actuator type ultrasonic vibrator 74, the circulation pumps 58 and 67 are used.
Even if it is stopped and drained under the open-to-atmosphere condition, a liquid pool occurs and the drainage performance is poor. Therefore, unless the number of washings after the drainage is repeated, a large number of particles remain, which may cause a measurement error in the next measurement. For example, in the conventional apparatus shown in FIG. 4, there is a possibility that liquid accumulation may occur at the bottom portion indicated by reference numeral A in the tube 58c of the roller pump 58 or at the bottom portion indicated by reference numeral B in the sample liquid outlet pipe 80. . In the conventional apparatus shown in FIG.
There is a possibility that a liquid pool may be generated at a bottom portion indicated by reference sign C in the cover 71 of the rotary blade 70 of No. 7. Also, in the conventional apparatus shown in FIG.
There is a possibility that a liquid pool may be generated in a lower portion including a bottom indicated by reference numeral D in the cover 71 of the rotary blade 70 of No. 7. Further, in the conventional apparatus shown in FIG. 7, there is a possibility that a liquid pool may be generated in a dead space or a bottom portion in the case 90 of the ultrasonic transducer 74 of the actuator type. The present invention has been made in consideration of the above-mentioned problems, and has as its object to easily control a circulating flow rate of a sample liquid, to arrange a circulating pump excellent in maintenance so as not to leak the liquid, To provide a light-scattering particle size distribution measurement device that can irradiate ultrasonic waves even with a sample liquid and improve drainage performance without forming a liquid pool in the open-to-atmosphere state without operating a circulation pump and forcibly draining water. It is. In order to achieve the above-mentioned object, the present invention comprises a sample medium comprising a dispersion medium and particles dispersed in the dispersion medium, and ultrasonic waves are applied to the sample liquid. A dispersion bath for dispersing the particles in the dispersion medium while irradiating the aggregation of the particles by irradiation is connected to the flow cell through a circulation flow path in which the sample liquid circulates by a centrifugal pump, and the sample liquid flowing in the flow cell is connected to the dispersion bath. In the light scattering type particle size distribution measuring device configured to measure the particle size distribution of the particles in the sample liquid based on the diffraction / scattered light pattern at that time, the dispersion bath has a flat surface. An inclined bottom surface, a side surface provided in a state of being continuously provided in a vertical direction from the inclined bottom surface and provided in a state of being inclined in one direction, and a horizontal opening formed above the inclined side surface. Bottom territory A sample liquid outlet is provided in the area, and an ultrasonic vibrator is attached to an area other than the lowermost area, and a discharge pipe for discharging the sample liquid or the dispersion medium in the dispersion bath communicates with the sample liquid outlet. Provided in a state protruding in the direction along the one direction below the sample liquid outlet, so that
A drive shaft of the centrifugal pump was attached to the cover body of the rotary blade by being tilted in a direction along the one direction so as to be connected to the rotary blade of the centrifugal pump through the discharge pipe from above the horizontal opening. The discharge port is inclined downward. Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1, 2 and 3, reference numeral 1 denotes a dispersion bath, which is made of, for example, stainless steel, and is a sample liquid comprising a dispersion medium (for example, pure water or alcohol) P and particles dispersed in the dispersion medium. S is accommodated. This distributed bus
For example, the horizontal opening 6 of the dispersing bath 1 is formed on the floor of the apparatus installation room by cutting the bottom of the cylindrical body having a height of G and cutting the opening side of the cylindrical body obliquely and horizontally so as to leave the minimum height H. It is attached to a chassis (not shown) of the apparatus in a state where it is inclined so as to be parallel to the apparatus. That is, the bottom surface of the distributed bath 1 is a flat inclined bottom surface 2 having a circular shape in plan view and inclined with the inclination angle θ (see FIGS. 1 and 3) with respect to the floor surface. The side surface 3 of the distribution bus 1 is provided in a state of being continuously connected to the inclined bottom surface 2 in the vertical direction and inclined in one direction (N direction). That is, the horizontal opening 6 is formed above the inclined side surface 3. Reference numeral 5 denotes a ring-shaped outward flange extending horizontally outward from the upper end of the side surface 3, and 5a denotes a rising portion which rises vertically from an end of the outward flange 5. The dispersion bath 1 is provided with a sample liquid outlet 7 in the lowermost region of the inclined bottom surface 2. For example, the sample liquid outlet 7 is formed by an annular downward flange 7a obtained by bending a part of the inclined bottom surface 2 downward. In this embodiment, in order to prevent particles from accumulating in the corners, a radius portion is provided in the continuous portion 8 in terms of function.
The sample liquid outlet 7 is provided at a position adjacent to the round portion avoiding the round portion. When the connecting portion 8 is formed in a right angle as shown by a dotted line, the sample liquid outlet 7 can be further provided below, and the liquid pool in the dispersion bath 1 can be more effectively prevented. . Reference numeral 9 denotes an ultrasonic vibrator, which is an outer surface 2 of the inclined bottom surface 2.
a. This attachment may be performed using an adhesive, and a screw member is provided on the outer surface 2 a of the inclined bottom surface 2, and a screw hole is provided at a position of the ultrasonic vibrator 9 at a position facing the screw member, thereby making it possible to use the adhesive. The ultrasonic transducer 9 may be attached to the outer surface 2a by screwing. in this way,
By attaching the ultrasonic vibrator 9 directly to the inclined bottom surface 2 of the dispersion bath 1, it is possible to irradiate ultrasonic waves up to the water level 10 of the sample liquid S indicated by a two-dot chain line. Reference numeral 11 denotes a flow cell, and the dispersion bath 1 is a centrifugal pump 12 and a drain valve (switching valve) 13 to be described later.
Are connected by a circulation flow path 14 having The drain valve 13 switches between the circulation channel 14 and the drain channel 40. Reference numeral 45 denotes a solenoid for switching the drain valve 13. 50 is the side surface 3 of the distributed bus 1
Overflow port 50a provided at the full water level in
And an overflow channel connecting the drain channel 40 and the drain channel 40. A discharge pipe 15 is provided below the outlet 7 so as to communicate with the sample liquid outlet 7.
Direction) is provided in a state protruding in the direction along
For example, it is made of stainless steel. This discharge pipe 15 is
It has a pipe hole 15a (see FIG. 3) having a diameter larger than the outer diameter of the downward flange 7a of the sample liquid outlet 7, and is externally fitted to the downward flange 7a at the sample liquid outlet 7 by, for example, brazing. ing. Of course, fixing means other than brazing may be used. The discharge pipe 15 discharges the sample liquid S in the dispersion bath 1 at the time of measurement.
The sample liquid S is discharged to the flow cell 11 via the drain valve 3, the sample liquid S is discharged to the drain passage 40 through the drain valve 13 when the sample liquid S is drained after the measurement, and the dispersion medium is stored during the washing after the drain. Dispersion bath 1 from tank 42 via pump 43 and dispersion medium supply valve 44
The dispersion medium P automatically supplied to the inside is discharged to the flow cell 11 side through the drain valve 13, and when the dispersion medium P is drained after the completion of the washing, the dispersion medium P is discharged through the drain valve 13 to the drain passage 40. Used to discharge to Reference numeral 46 denotes a solenoid for opening and closing the dispersion medium supply valve 44. Reference numeral 47 denotes a return port 48 for the sample liquid S or the dispersion medium P.
Is formed at an appropriate position below the overflow port 50 a on the side surface 3 of the distribution bus 1. Reference numeral 49 denotes a liquid level sensor which detects the water level 10 indicated by a two-dot chain line, a full water level, or a predetermined water level between both water levels, and detects the ultrasonic vibrator 9, the centrifugal pump 12,
The drain valve 13, the dispersion medium supply valve 44, and the pump 43 are opened and closed. Hereinafter, the centrifugal pump 12 will be described.
The centrifugal pump 12 includes a drive shaft 16, a motor 18 for driving the drive shaft 16 via a transmission mechanism such as a pulley 16 a and a belt 16 b, a rotating blade 19, and a resin or metal covering the rotating blade 19. And the cover body 20 of FIG. The cover body 20 includes an upper small-diameter portion 21 for connecting the cover body 20 to the discharge pipe 15 in a watertight manner,
The sample liquid S or the dispersion medium P sucked from the center of the rotating wing 19 while containing the rotating wing 19
The lower large-diameter portion 23 has a discharge port 25 for discharging to the third side on the peripheral wall 22. The discharge port 25
As shown in FIG. 3, is a cylindrical shape that projects horizontally from the peripheral wall 22 of the lower large-diameter portion 23 in the tangential direction, and the axis L is the inner bottom surface 25a of the discharge port 25 (see FIG. ). The drive shaft 16 is mounted to be inclined in the one direction (N direction) so as to be connected to the rotary blade 19 from above the horizontal opening 6 through the discharge pipe 15. . That is, as shown in FIG. 3, the drive shaft 16 is inclined by the above-described inclination angle θ with respect to the vertical axis Y. In FIG. 3, the Y 'axis coincides with the axis of the drive shaft 16 and faces in the direction along the N direction. Thus, the discharge port 25 is provided to be inclined downward. Further, in this embodiment, the centrifugal pump 12
The inner bottom surface 23a of the lower large-diameter portion 23 is connected to the high portion T on the upstream side through the step m so as not to generate liquid pools in the cover body 20 in the open-to-atmosphere state even when forced water is drained. It is formed in a lower portion t on the side. As a result, even if the centrifugal pump 12 is operated and forced drainage is not performed, liquid accumulation does not occur in the cover body 20 in the open-to-atmosphere state. Reference numeral 30 denotes a central hole penetrating the upper small diameter portion 21 in the direction of the vertical axis Y '.
Connect to 4. The central hole 30 is formed with a screw 32 that is screwed to the screw member 31, and an annular groove 34 in which an annular seal member 33 is fitted is formed immediately below the screw 32. Therefore, the cover member 20 is inserted into the discharge pipe 15 through the central hole 30 with the seal member 33 fitted in the annular groove 34, and the seal member 33 is tightened by the screw member 31 while the screw 32 is tightened. By deforming, the cover body 20 can be connected to the discharge pipe 15 in a watertight manner. The centrifugal pump 12 applies a centrifugal force to the sample liquid S or the dispersion medium P by the rotating rotor 19 to generate pressure to circulate or drain the sample liquid S or the dispersion medium. . As described above, the discharge port portion 25 is provided to be inclined downward, and the procedure for attaching the cover body 20 for that purpose is as follows. First, the cover body 20 is set in the direction of the vertical axis Y '.
In this case, the discharge port 25 is inclined downward as shown by the dashed line in FIG. At this time, the axis of the lower large-diameter portion 23 is not the axis L but the axis X ′. This axis X '
Indicates a direction (M direction) perpendicular to the direction of the vertical axis Y ′. That is, the direction is perpendicular to the paper surface of FIG. Subsequently, in order to reliably prevent liquid pooling not only on the inner bottom surface 23a of the lower large-diameter portion 23 but also on the inner bottom surface 25a of the discharge port portion 25 (see FIG. 2) in the open-to-atmosphere state, the tightening by the screw member 31 is performed. By setting the cover body 20 by swinging the cover body 20 outward by a predetermined angle in the J direction (see FIG. 3) around the vertical axis Y ′, the axis of the lower large-diameter portion 23 is set to the axis L.
To match. Thus, at the time of discharge, the inclined bottom surface 2 of the dispersion bath 1, the inner wall of the discharge pipe 15, the inner bottom surface 23a of the cover body 20, and the discharge port portion are kept open to the atmosphere without operating the circulation pump 12. Liquid pool does not occur over the inner bottom surface 25a of the nozzle 25. Further, since the centrifugal pump 12 is used as the circulation pump, a large flow rate can be obtained.
It is not necessary to periodically replace the tube 58c as in the above. Further, since the ultrasonic vibrator 9 can be directly attached to the inclined bottom surface 2 of the dispersion bath 1, the structure is simplified.
Further, ultrasonic dispersion can be performed even with a small amount of the sample liquid S such that ultrasonic irradiation can be performed up to the water level 10 indicated by the two-dot chain line. In addition, since there is no need to seal the drive shaft 16 of the centrifugal pump 12, there is no risk of liquid leakage. As described above, according to the present invention, as a circulating pump, a circulating flow rate of a sample solution can be easily controlled, and a centrifugal pump having excellent maintainability can be arranged so as not to leak liquid. The effect of providing a light-scattering particle size distribution measuring device which can improve the drainage performance without forming a liquid pool in the open-to-atmosphere state without operating the circulating pump and forcibly draining the water while being able to irradiate ultrasonic waves even with the sample liquid. is there.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of the overall configuration showing an embodiment of the present invention. FIG. 2 is an explanatory diagram of a main part configuration in the embodiment. FIG. 3 is a view for explaining a state of attachment of a cover body to a discharge pipe in the embodiment. FIG. 4 is an explanatory diagram of the entire configuration showing a first conventional configuration. FIG. 5 is an explanatory diagram of the entire configuration showing a second conventional configuration. FIG. 6 is an explanatory diagram of the entire configuration showing a third conventional configuration. FIG. 7 is an explanatory diagram of the entire configuration showing a fourth conventional configuration. [Description of Signs] 1 ... Dispersion bath, 2 ... Slope bottom, 3 ... Side, 6 ... Horizontal opening, 7 ... Sample liquid outlet, 9 ... Ultrasonic vibrator, 11 ... Flow cell, 12 ... Centrifugal pump, 13 ... Drain valve, 14 ...
Circulation flow path, 15 ... Discharge pipe, 16 ... Drive shaft, 19 ...
Rotor blade, 20: cover body, 21: upper small diameter part, 23: lower large diameter part, 25: discharge port, P: dispersion medium, S: sample liquid.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-149864 (JP, A) JP-A-6-241975 (JP, A) JP-A-7-8755 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) G01N 15/02 G01N 15/14

Claims (1)

(57) [Claim 1] A dispersion medium and a sample liquid comprising particles dispersed in the dispersion medium are accommodated, and the sample liquid is irradiated with ultrasonic waves to disperse the aggregation of particles. A dispersion bath for dispersing the particles in the dispersion medium is connected to the flow cell via a circulation channel through which the sample liquid circulates by a centrifugal pump, and the sample liquid flowing in the flow cell is irradiated with laser light. In the light scattering type particle size distribution measuring device configured to measure the particle size distribution of particles in the sample liquid based on the diffraction / scattered light pattern of, the dispersion bath has a flat inclined bottom surface, and a vertical surface extending from the inclined bottom surface. A side surface that is provided in a state of being inclined in one direction, and a horizontal opening formed above the inclined side surface, and a sample liquid outlet is provided in a lowermost region of the inclined bottom surface. Along with the bottom An ultrasonic vibrator is attached to a region excluding the region, and the one direction is provided below the sample liquid outlet so that a discharge pipe for discharging a sample liquid or a dispersion medium in a dispersion bath communicates with the sample liquid outlet. And the drive shaft of the centrifugal pump is tilted in the direction along the one direction so as to be connected to the rotor of the centrifugal pump from above the horizontal opening through the discharge pipe. A light-scattering type particle size distribution measuring device, wherein a discharge port provided on a cover body of the rotor is inclined downward.