Optical process and apparatus for determining particle size of colloidal solution
First Claim
1. A method for determining the particle size of a colloidal solution, especially a synthetic resin dispersion, the method including the steps of:
- providing a colloidal solution sample with a thickness which varies in a given direction;
directing a light beam to propagate through the colloidal solution sample in the direction normal to said given direction;
causing the emerging light beam from the sample to undergo chromatic dispersion and to be incident onto an image screen;
establishing, by a relative displacement between the light beam and the varying thickness of the colloidal solution sample, a sample position which results in only the long-wave part of the visible spectrum to appear on the screen;
determining the thickness of the colloidal solution section which is traversed by the beam at said position; and
, determining the particle size of the colloidal solution in accordance with the formula;
##EQU5## where r=radius of the particle (μ
m),c=concentration of the colloidal solution in volume %,d=thickness of measured colloidal solution sample section (mm),E.sub.(c) =concentration factor at concentration c, andn=a constant.
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Abstract
Method and apparatus for determining the colloid size of particles in a colloidal solution include the use of a wedge-shaped container for a sample of the colloidal solution. The container is moved in the direction of the wedge shape perpendicular to the path of a light beam to produce a measured sample thickness of the colloidal solution. Due to the Tyndall effect, the measured sample thickness is a function of the scattering of the light beam. A lens arranged between the sample holder and a dispersion prism directs the beam of light emerging from the sample holder to the prism for dispersion and impingement upon an image screen. The sample holder is moved until only red light appears on the image screen. The thickness of the light path through the sample is measured and the particle size is computed according to an equation.
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Citations
10 Claims
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1. A method for determining the particle size of a colloidal solution, especially a synthetic resin dispersion, the method including the steps of:
- providing a colloidal solution sample with a thickness which varies in a given direction;
directing a light beam to propagate through the colloidal solution sample in the direction normal to said given direction;
causing the emerging light beam from the sample to undergo chromatic dispersion and to be incident onto an image screen;
establishing, by a relative displacement between the light beam and the varying thickness of the colloidal solution sample, a sample position which results in only the long-wave part of the visible spectrum to appear on the screen;
determining the thickness of the colloidal solution section which is traversed by the beam at said position; and
, determining the particle size of the colloidal solution in accordance with the formula;
##EQU5## where r=radius of the particle (μ
m),c=concentration of the colloidal solution in volume %, d=thickness of measured colloidal solution sample section (mm), E.sub.(c) =concentration factor at concentration c, and n=a constant. - View Dependent Claims (2, 3, 4, 5)
- providing a colloidal solution sample with a thickness which varies in a given direction;
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6. Apparatus for determining the particle size of a colloidal solution, especially a synthetic resin dispersion, said apparatus including the combination of:
- a light source;
a condenser to direct light from said light source for producing a narrow light beam;
a wedge-shaped transparent sample holder for displacement in the direction of the wedge shape thereof within the path of the narrow light beam passed from said condenser, said sample holder being adapted to contain a sample of colloidal solution for the determination of the particle size thereof;
lens means arranged for propagating light passed through said sample holder;
means for dispersing light propagating from said lens means into the visible light spectrum; and
an image screen for impingement by the dispersed light propagated from the dispersion means. - View Dependent Claims (7, 8, 9, 10)
- a light source;
Specification