subject: On The Particle Size Test Of Basic Knowledge And Methods - Size Test, The Basic Approach - Education [print this page] Particle size measurement is through specific instruments and methods to characterize the particle size characteristics of an experimental work. Powder in our daily lives and industrial and agricultural production is widely used. Such as flour, cement, plastic, paper, rubber, ceramics, pharmaceuticals and so on. Applications in different fields, on the powder characteristics of the request is different, and in all the indicators reflect the powder characteristics, the size distribution of all applications in the most talked about an indicator. So objectively reflect the real size distribution of powders is a very important task. Here to talk about my specific size test on the base of knowledge and basic methods.
1, the basic knowledge of particle size test
1, particles: a size range with a specific geometric shape. Mentioned here is generally a size mm to nanometers, particles not only refers to solid particles, as well as droplets, oil droplets and other liquid particles.
2, powders: from a large number of particles of different sizes of particles formed groups.
3, size: size of the particles is called the particle size.
4, particle size distribution: with special instruments and methods reflect the different particle size accounts for the percentage of the total powder. A range of distribution and the cumulative distribution of two forms. Interval distribution is also known as differential distribution or frequency distribution, it said the number of size fractions in percentage content of particles. Cumulative distribution is also called the distribution points, it said less than or greater than a percentage content of particles.
5, particle size distribution of Representation:
Table Method: The method table size range distribution, the cumulative distribution of 11 methods listed.
graphical method: standard system used in the rectangular form of histograms and curves, said the method of particle size distribution.
Function: The size distribution of mathematical functions that way. This method generally used in theoretical studies. Such as the famous Rosin-Rammler distribution is the distribution function.
6, particle size and equivalent diameter:
Size is the particle diameter. This concept is very simple and clear, then what is it equivalent size, particle size and the equivalent particle size matter? We know that only spherical diameter only, other geometric shapes are not the diameter, which consists of powder particles are predominately not spherical, but a variety of irregular shape, with flake, needle, multi-row-like, etc.. The complex shape of the particle theory, can not be directly used to express the concept of the diameter of its size. In the practical work is to describe a particle size diameter of the most intuitive and easiest one volume, we hope that such a volume can be used to describe the particle size, so size of our practice test, the equivalent grain Path concept.
Equivalent diameter is a particle when the physical characteristics of a homogeneous spherical particles with the same or similar, we used the diameter of spherical particles to represent the actual particle diameter. Then the spherical particle size is the equivalent of the actual particle size. Equivalent diameter of the concrete has the following categories:
equivalent volume diameter: the same with the actual particle volume diameter of the ball. Measured by laser method is generally believed that the diameter of equivalent volume diameter.
equivalent on the velocity track: Under the same conditions and the actual particle settling velocity for the same ball diameter. Sedimentation particle size measured settling velocity equivalent diameter, also known as Stokes diameter.
equivalent resistance path: Under the same conditions produce the same resistance and the actual effects of particles, spherical particles of diameter. Kurt method measured the diameter of the equivalent resistance path.
Dropping area equivalent diameter: Dropping the same size and the actual particle diameter of spherical particles.
