JPH025404Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a particle size distribution measuring device, and more specifically, it involves uniformly dispersing sample particles in a medium solution, settling them under centrifugal force, and discharging them in the medium solution at a certain sedimentation distance. The present invention relates to a particle size distribution measuring device using a so-called centrifugal sedimentation method, which measures the concentration of sample particles and measures the particle size distribution of sample particles from temporal changes in concentration by utilizing the difference in sedimentation rate with respect to particle size.

Generally, in this type of device, the concentration detection position is fixed at one location, so particles with a high sedimentation rate (particles with a large particle size) settle too quickly and cannot be detected, and particles with a low sedimentation rate (large particles) There is a problem in that it takes a long time for particles with small diameters to settle to the concentration detection position. Conventionally, in order to solve this problem, concentration detectors were installed at multiple locations with different sedimentation distances, and particles with a large sedimentation velocity were detected by the concentration detectors installed at positions with a large sedimentation distance.
A device was used in which particles with a low sedimentation velocity were detected by a concentration detector installed at a position where the sedimentation distance was small. By doing this,
Concentration signals can be obtained simultaneously at positions with different sedimentation distances for one type of sample particle, making it possible to obtain accurate distributions even for particles with high sedimentation speeds, and to quickly obtain the distribution of particles with low sedimentation speeds. Now we can measure the distribution. However, such conventional devices require a plurality of concentration detectors, which inevitably results in disadvantages such as increased device size, complicated adjustment, and increased cost.

The present invention was made in view of the above, and includes:
By using multiple concentration detectors, it is possible to simultaneously obtain concentration signals at different positions with different sedimentation distances as described above, and by using these signals, it is possible to obtain integrated particle size distribution curves in a short time, as well as differential particle size distribution curves. The object of the present invention is to provide a particle size distribution measuring device that can also determine a distribution curve.

The feature of the present invention is that it is equipped with a plurality of sedimentation containers for sealing the sample particles uniformly dispersed in a medium solution and applying centrifugal force, and a single concentration detector is used to The concentration signals at different sedimentation distances as described above can be obtained simultaneously by separately capturing particle concentrations in a plurality of sedimentation containers and by making the solution level in each sedimentation container different. In addition to obtaining an integrated particle size distribution curve in a short time, a circuit for subtracting these signals is further provided to obtain a differential particle size distribution curve.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a front view of a rotating disk 3 thereof.

The first and second sedimentation vessels 1a and 1b seal the sample particles uniformly dispersed in the medium solution,
They are mounted on a rotating disk 3 attached to the rotating shaft of the motor 2 at positions facing each other across the center of rotation. Predetermined distance R ₂ from the rotation center O of the rotating disk
A concentration detection light source 4 that emits light that crosses the settling vessels 1a and 1b and a concentration detection light receiving section 5 that receives the light and converts it into an electrical quantity and outputs it are provided. The light source 4 for concentration detection and the light receiving section 5 for concentration detection are connected to each sedimentation container 1 by a light transmission method.
Detect the concentration of the sample particles in the medium solution in a and 1b.
The output of the concentration detection light receiving section 5 is introduced to a signal discrimination switch 7 via a preamplifier 6. On the other hand, a sedimentation container position detection disk 8 is fixed to the rotating shaft of the motor 2, and the first and second sedimentation containers 1a and 1b are located on the container position detection disk 8 at positions where the light beams of the concentration detection light source 5 cross each other. The hole is bored at a position such that the light from the position detection light source 9 enters the position detection light receiving section 10 when the position detection light source 9 reaches the position detection light receiving section 10. Therefore, the position detection light receiving section 10 is connected to each sedimentation container 1a,
1b reaches the concentration detection position, and by introducing the detection signal into the signal discrimination switch 7, the sample in the medium solution in the first and second sedimentation containers 1a and 1b is detected. The particle concentration signals are configured to be separated into respective concentration signals and supplied to first and second amplifiers 11a and 11b, respectively. The outputs of the first and second amplifiers 11a and 11b are each independently introduced into the two-pen coder 12, and
The subtraction circuit 13 subtracts the output of the second amplifier 11b from the output of the first amplifier 11a and outputs the result to the recorder 14.

Next, the function of this embodiment of the present invention will be described along with the method of use.

First, a solution in which test particles are uniformly dispersed in a medium solution is poured into the first and second sedimentation vessels 1a and 1.
b, but at this time, the amount of sealed water is different for each, and the distances from the center of rotation O to the liquid level of each solution are R ₁ (A) and R ₁ (B), respectively, as shown in Figure 2. Record it. Next, when the motor 2 is rotated, the first and second sedimentation vessels 1a and 1
b alternately crosses the light beam from the concentration detection light source 4, and the concentration signal from the concentration detection light receiving section 5 is discriminated by the signal discrimination switch 7 into concentration signals in the first and second settling vessels 1a and 1b, respectively. First
and introduced into second amplifiers 11a and 11b. Here, when particles settle in a rotating field, let R ₁ be the distance from the center of rotation to the liquid level, R ₂ be the distance from the center of rotation to the detection point, and let T and K be constants for the time from the starting point of sedimentation. , the particle diameter D _P that passes through the detection point can be determined using the following formula.

D _P =k(1/T)log(R ₂ /R ₁ ) For the first and second settling vessels 1a and 1b, R ₂ is the same in the above equation, but R ₁ is R ₁ (A) and R ₁ (B), so
The concentration signals of both at a certain elapsed time T are that the first sedimentation vessel 1a has a particle concentration smaller than the particle size D _P (A), and the second sedimentation vessel 1b has a particle concentration of D _P (B ) is the concentration of particles with a smaller diameter than the particles with a diameter of When the concentration signals from the first and second amplifiers 11a and 11b are subtracted by the subtraction circuit 13, particles existing in the particle interval between D _P (A) and D _P (B) at a certain elapsed time T are found. This means that the amount has been obtained. If this is continuously determined and recorded on the recorder 14, a distribution curve of the amount of particles existing in each particle size section, that is, a differential particle size distribution curve is obtained. On the other hand, the first and second amplifiers 11
If the outputs of a and 11b are recorded independently over time using the two-pen recorder 12, concentration signals at different sedimentation distances can be obtained at the same time. It is possible to obtain the same results as when separately provided, that is, to obtain an integrated particle size distribution curve in a short time.

As explained above, according to the present invention, it is possible to obtain the same effect using a single concentration detector as when using multiple concentration detectors, and it is also possible to easily obtain a differential particle size distribution curve. Furthermore, it has become possible to easily adjust and provide the device at low cost without increasing the size.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a front view of its rotating disk. 1a, 1b...first and second settling containers, 3
...Rotating disk, 4...Light source for concentration detection, 5...Light receiving section for concentration detection, 7...Signal discrimination switch, 8...
...Container position detection disk, 12...2 pen recorder,
13...Subtraction circuit, 14...Recorder.

Claims (1)

[Scope of utility model registration request] The sample particles uniformly dispersed in the medium solution are sealed in a sedimentation container and allowed to settle under centrifugal force, and the concentration of the sample particles in the medium solution in the sedimentation container is detected at a certain sedimentation distance. A device for measuring the particle size distribution of a sample particle based on a temporal change in the concentration thereof, which comprises a plurality of the sedimentation vessels, and a detection signal from the concentration detection means is transmitted to the sedimentation vessels of the plurality of sedimentation vessels. A means for discriminating the concentration signals of each container, and a subtraction circuit receiving the discriminated plurality of concentration signals as input, and by varying the liquid level of the solution in the plurality of sedimentation containers. , it is possible to simultaneously detect concentrations for a plurality of different sedimentation distances, use the plurality of concentrations independently to simultaneously measure the particle size distribution of the sample grains, and use the plurality of concentration signals as described above. A particle size distribution measuring device characterized in that it is configured to be installed in a calculation circuit to obtain a differential particle size distribution curve.