JP3422708B2 - Particle size distribution measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle size distribution measuring device for measuring a particle size distribution of particles such as a powder sample. 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. One of the methods for measuring such particle distribution is a laser diffraction scattering particle size distribution measuring method. In this particle size distribution measuring method, for example, a powder sample is dispersed and stirred in a liquid called a dispersion medium to form a suspension, and the suspension is introduced into a flow cell.
In that state, the flow cell is irradiated with laser light, and the diffraction and / or scattered light at that time is detected by a detector, and the intensity distribution of the diffraction and / or scattered light obtained by this is determined by the Franhofer diffraction, Mie scattering theory To determine the particle size distribution of the sample. [0003] A dispersion bath for dispersing a sample in a dispersion medium to form a suspension is connected to a flow cell via a circulation channel, and the suspension is circulated and supplied to the flow cell. In the particle size distribution measuring device to measure
Conventionally, a valve for switching between supplying the suspension to the flow cell and discharging the suspension as a drain and a cell holder of the flow cell are separately formed, and both are connected via a circulation channel. [0004] However, in the above configuration, it is difficult to smoothly circulate large particles due to a long circulation channel, and particles accumulate in a pipe portion associated with large particles. Occurred. Further, separately installing the drain switching valve and the flow cell holder has caused an increase in cost. The present invention has been made in consideration of the above-mentioned matters, and has as its object to measure the particle size distribution capable of increasing the liquid feeding efficiency by shortening the circulation flow path and reducing the cost. It is to provide a device. Means for Solving the Problems To achieve the above object, the technical technique adopted by the present invention is as follows. That is, in a particle diameter distribution measuring device in which a dispersion bath and a flow cell, which are a suspension obtained by dispersing a sample in a dispersion medium, are connected through a circulation channel, and the suspension is circulated and supplied to the flow cell for measurement. A valve-integrated flow cell holder in which a valve for switching between supplying the suspension to the flow cell and discharging as a drain, and a cell holder of the flow cell were provided. [0007] According to the above-described method, the piping between the drain switching valve and the flow cell holder is made piping-less, so that the circulation flow path is shortened, the liquid feeding efficiency is increased, and larger particles can be circulated. There is no accumulation of particles in the piping. In addition, cost reduction can be achieved by being integrated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a configuration of a particle size distribution measuring device according to one embodiment of the present invention. The dispersion bath 2 is a measuring sample (for example, powder) to be input.
And a dispersion medium (for example, pure water or alcohol) for dispersing the same, which is a cylindrical liquid tank that is made into a suspension. It is connected to the. In the circulation flow path 3, the outgoing pipe 6 on the side from which the suspension flows out of the dispersing bath 2 is connected to the bottom surface of the dispersing bus 2, and the circulating pump 5 arranged in the middle of the outgoing pipe 6 is driven by the motor 4. You. In the circulation channel 3, a return pipe 7 on the side where the suspension flows into the dispersion bus 2 is connected to the peripheral wall of the dispersion bus 2. An ultrasonic vibrator 8 is provided to prevent the suspension from agglomerating in the dispersion bath 2 by driving the ultrasonic vibrator 8. A drain passage 9 is connected to the circulation passage 3 via the valve-integrated flow cell holder 1. Then, by switching the valves in the valve-integrated flow cell holder 1, the connection and disconnection between the circulation channel 3 and the drain channel 9 are performed. Switching of the valve 16 in the valve integrated flow cell holder 1 is performed by a solenoid 11. Further, the upper position of the peripheral wall of the dispersion bath 2 and the drain passage 9 are connected via an overflow passage 10, and when the suspension in the dispersion bath 2 exceeds a predetermined liquid level, the excess Suspension overflow channel 1
0, and is led out to the drain passage 9. FIG. 2 is a longitudinal sectional view of the valve integrated flow cell holder 1 in the above embodiment. The main body 12 of the valve integrated flow cell holder 1 is made of, for example, metal (such as stainless steel) or resin (such as fluororesin), and is provided with a valve 16 integrally. A substantially rectangular parallelepiped concave portion 17 is formed at the center of the upper surface of the main body 12.
The lower end of the flow cell 13 is removably inserted into the groove 17, and an annular O-ring groove 18 is formed on the lower surface of the concave portion 17.
An O-ring 19 is fitted into the ring groove 18 and the O-ring 19
The peripheral edge of the lower surface opening of the flow cell 13 abuts on this. At this time, a gap 3 is provided between the side surface of the recess 17 and the flow cell 13.
There are eight. Reference numeral 22 denotes an introduction hole formed in the main body 12 from the introduction port 21 to the center of the lower surface of the recess 17.
A communication hole 23 is formed between one end of the second and the recess 17, and the inlet 21, the introduction hole 22, the communication hole 23, and the lower surface opening of the flow cell 13 communicate with each other. The lower end of the flow cell 13 has a projection 20 protruding from the wall surface of the recess 17 and a support bolt 2 screwed into a screw hole 15 provided on the wall surface opposite thereto.
It is tightened by 4. Reference numeral 14 denotes an upper holder formed separately from the valve integrated type flow cell holder 1. A concave portion 25 is formed in the center of the lower surface of the upper holder, and the upper end of the flow cell 13 is inserted into and removed from the concave portion 25. It is freely inserted and supported, and an annular O-ring groove 26 is formed on the upper surface of the concave portion 25.
The O-ring 27 is fitted into the ring groove 26, and the O-ring 27
The peripheral edge of the upper opening of the flow cell 13 abuts on this. 28
Are discharge holes formed in the upper holder 14, and the discharge holes 28
A communication hole 29 is formed between one end of the hole 25 and the concave portion 25, and a discharge port 30 is connected to the other end of the discharge hole 28 and led out to the other side. The discharge port 30, the discharge hole 28, the communication hole 29, and the flow cell Thirteen upper surface openings communicate with each other. The flow cell 13 is sandwiched between an upper holder 14 and a flow cell holder 1 integrated with a valve, and is fixed by tightening both holders 14 and 1 from above and below (not shown). In addition, a laser light source 36 provided on one side of the flow cell 13, a condenser lens (not shown) provided on the other side, a photodetector 37, and a signal processing unit for processing an output signal from the photodetector 37 ( (Not shown), etc., irradiates the flow cell 13 with laser light in a state where the suspension circulates in the circulation flow path 3 and diffracts and / or scatters the light at that time. Detection is performed to determine the intensity distribution of the diffraction and / or scattered light obtained thereby, and the particle size distribution of the sample is determined based on the theory of Franhofer diffraction and Mie scattering. The valve 16 of the main body 12 mainly comprises a valve chamber 31, a valve seat 32, a valve body 33, a drain inlet 34, and a drain outlet 35. The drain inlet 34 is connected to one end of the horizontal portion of the inlet 22. And the drain inlet 34
A valve seat 32 is formed in the shape of a tapered surface toward the inside of the valve chamber 31. Further, the valve body 33 is connected to the solenoid 11, and the tip of the valve body 33 forms a tapered surface whose gradient is gentler than that of the valve seat 32. The valve seat 32 is made of relatively hard rubber, and the valve body 33 is made of rubber whose surface is at least relatively soft.
In this case, since the valve body 33 is appropriately deformed, the portion where the two come into contact with each other is not a line but a surface, so that a stronger seal can be obtained. For example, even if large particles are caught, water does not leak. Reference numeral 40 denotes a buffer spring provided between the spring supports 41 and 42. Next, the operation of the valve integrated flow cell holder 1 will be described. The valve 16 in the valve-integrated flow cell holder 1 is switched by the solenoid 11. That is, when the solenoid 11 is turned on, the rod 36 advances, the valve seat 32 and the valve body 33 come into contact with each other, and the drain inlet 34 is closed. Therefore, the suspension flowing from the inlet 21 through the outward pipe 6 is It flows out from the outlet 30 to the return pipe 7 via the flow cell 13. In this state, measurement by the measurement system becomes possible. Conversely, when the solenoid 11 is turned off, the rod 36 retreats and the valve seat 32
And the valve body 33 are separated, and the drain introduction port 34 is opened.
The suspension flowing from the inlet 21 through the outgoing pipe 6 flows out of the drain outlet 34 through the valve chamber 31 to the drain passage 9 through the drain outlet 35. As described above, according to the present invention, a dispersion bath in which a sample is dispersed in a dispersion medium to form a suspension is connected to a flow cell via a circulation channel, and the suspension is In a particle size distribution measuring device for measuring by circulating and supplying the suspension to a flow cell, a valve for switching between supplying the suspension to the flow cell or discharging the suspension as a drain, and a valve integrated type in which the cell holder of the flow cell is integrated By providing the flow cell holder, piping between the drain switching valve and the flow cell holder becomes unnecessary, and the circulation flow path is shortened, so that large particles can be easily circulated,
Further, it is possible to prevent the accumulation of particles in the pipe portion associated with the large particles, and to reduce the cost by integrally forming the drain switching valve and the flow cell holder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a configuration of a particle size distribution measuring device according to one embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the valve-integrated flow cell holder in the embodiment. [Description of Signs] 1 ... Flow cell holder with integrated valve, 2 ... Distribution bath, 3
... Circulation channel, 9 ... Drainage channel, 13 ... Flow cell, 16 ...
valve.

Claims (1)

(57) [Claim 1] A dispersion bath in which a sample is dispersed in a dispersion medium to form a suspension is connected to a flow cell via a circulation channel,
In a particle size distribution measuring apparatus for measuring a suspension by circulating and supplying the suspension to a flow cell, a valve for switching whether the suspension is supplied to the flow cell or discharged as a drain is integrated with a cell holder of the flow cell. Particle size distribution measuring device equipped with a valve integrated flow cell holder.