Laser-based apparatus and method for measuring agglomerate concentration and mean agglomerate size
AssigneeProcess Metrix
InventorDonald John Holve
Life of this patent
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Abstract
Apparatuses, methods, and systems for measuring mean particle size and concentration of a polydispersion of agglomerates are disclosed. In one embodiment, the apparatuses include a light source; a focusing lens to form a probe volume; a first light detector positioned at a first angular position from the beam of light; and a second light detector positioned at a second angular position from the first direction of the beam of light, the mean particle size and concentration being determined using nearly invariant functions of a ratio of the light scattered measured by the first and second detectors.
Claims49
An apparatus for measuring average size and concentration of a polydispersed agglomerate of primary particles, the apparatus comprising:
- a light source configured to emit a beam of light in a first direction;
- a first light detector positioned at a first angular position, θ1, from the first direction of the beam of light, the first light detector being configured to generate a first signal proportional to light scattered onto the first light detector by the polydispersed agglomerate in a probe volume formed in the beam of light;
- and
- a second light detector positioned at a second angular position, θ2, from the first direction of the beam of light, the second light detector being configured to generate a second signal proportional to light scattered onto the second light detector by the polydispersed agglomerate in the probe volume, wherein an average concentration of the polydispersed agglomerate, Cm, per unit total scattered light, PTθ, is given by:
- C
- m
- P
- T
-
-
- θ
- =
- f
- 1
-
- f
- 2
-
- C
- m
-
- #
- ,
- where f1 is a function of optical properties of the primary particles, f2 is a function of a configuration of the apparatus, and Cm# is a nearly invariant first function of a scattering ratio, Rθ1/θ2, of the first signal to the second signal.
A method of measuring average size and concentration of a polydispersed agglomerate, the method comprising:
- emitting a beam of light from a light source in a first direction;
- measuring light scattered from the polydispersed agglomerate passing through a probe volume formed by the beam of light with a first light detector positioned at a first angular position, θ1, from the first direction of the beam of light;
- measuring light scattered from the polydispersed agglomerate passing through the probe volume with a second light detector positioned at a second angular position, θ2, from the first direction of the beam of light;
- and
- calculating, using a processor, an average concentration of the polydispersed agglomerate, Cm, per unit total scattered light, PTθ, using the following equation:
- C
- m
- P
- T
-
-
- θ
- =
- f
- 1
-
- f
- 2
-
- C
- m
-
- #
- ,
- where f1 is a function of primary particle optical properties, f2 is a function of a configuration of the apparatus, and Cm# is a nearly invariant first function of a ratio, Rθ1/θ2, of the scattered light measured by the first light detector to the scattered light measured by the second detector.
Dependencies are inferred from the claim text.