Turbidimetric method for on-line determination of latex particle number and particle size distribution

Zollars, Richard L.

doi:10.1016/0021-9797(80)90179-4

Cited by 64 publications

(17 citation statements)

References 6 publications

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“…For PSDs described by two parameters, three data points will be required and so on. Fortunately, the log-normal distribution has been found to be a good approximation for the PSD of a large number of lattices 1 . In this case we need two measurands to determine both the number concentration and an average particle size and three parameters to get N and a two-parametric PSD.…”

Section: Particle Concentration Measurementmentioning

confidence: 99%

Highly integrated optical microsystem for particle concentration measurement

Hofmann

Schneider

et al. 2010

SPIE Proceedings

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We present our research on integrated optical Talbot interferometers for particle mass concentration measurements. For optimum integration of highly sensitive optical measurement systems we apply a planar emitter-receiver-unit with a vertical cavity surface emitting laser (VCSEL) at 850 nm as light source. The optical system is integrated into a planar transparent PMMA (polymethylmethacrylate) substrate. We suggest a planar integrated free-space optical system for monitoring the particle mass concentration of polydisperse suspensions. Thorough simulations of the optical sensor show that for the required regime of particle concentration and particle size distribution (PSD) turbidity measurements where the attenuation of a light beam is evaluated for example at different wavelengths do not provide the required measurement precision. We therefore propose a system where the probe beam even though sent through the system is blocked before reaching the detector by an interferometric setup. The stray light originating from the particles is exploited for the measurement. For our application we focus on particles with sizes in the range 1 -120 μm and particle mass concentrations in the range of 1-10 mg/L. In this case significant strength of the scattering signal only appears in small angles relative to the incident probe beam (forward scattering). The probe beam and the stray light thus overlap to a large extent.Our sensor concept is based on a monolithically integrated Talbot interferometer. Two properly aligned diffraction gratings are used to remove the primary beam. We use a stripe detector as second grating. The stray light causes perturbations within the formation of the self image of the grating. These perturbations are visualized as speckles on a detector and exploited for particle concentration measurements. The potential of the sensor concept is presented on the example of a modular Talbot interferometer using a HeNe laser at 633 nm to measure particle mass concentrations between 1 mg/L and 250 mg/L of Arizona test dust. We present the results of our investigations concerning the generation of Talbot self images in the planar configuration using a diverging multimode VCSEL light source. Furthermore we discuss the design and demonstrate the fabrication of a planar optical test system containing the integrated passive optical elements necessary for forming an integrated Talbot interferometer. Light source and sensor are positioned on a separate chip.

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Section: Particle Concentration Measurementmentioning

confidence: 99%

Highly integrated optical microsystem for particle concentration measurement

Hofmann

Schneider

et al. 2010

SPIE Proceedings

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“…However, there have been only few papers published on turbidity-based reaction monitoring in the past [e.g. [73][74][75].…”

Section: Particle Sizingmentioning

confidence: 99%

Polymerization Online Monitoring

Frauendorfer¹,

Wolf²,

Hergeth³

2010

Chem Eng & Technol

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Online monitoring of polymerization reactions is not only important due to the high exothermic nature of most polymerization systems; the data gained also provides information on product composition and quality and control possibilities thereof. Many inline and online methods are still in development and are better suited for application on the laboratory or pilot-plant scale. Industrial polymerization plant environments pose additional technical and financial challenges and constraints for the use of such systems. Available methods and current developments are reviewed with regard to their practicability and usefulness under these aspects.

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“…Turbidimetry can also be used to provide quantitative information on the number of small particles in suspension. [8][9][10] Such sensors could provide reasonable information for the monitoring of the generation of nuclei even if bigger crystals cannot always satisfactorily be measured (that is, turbidimetry is not suitable for big particles). This is why the reconstruction of the entire CSD from the measurement of the number of nuclei particles would undeniably be a valuable result.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear observer of crystal‐size distribution during batch crystallization

et al. 2006

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A high-gain observer was designed to estimate the crystal-size distribution (CSD) in batch crystallization processes. The observer is based on the discretization of population balance equations describing the evolution of the CSD using finite difference method. Due to process impurities and other batch-to-batch variations, the kinetic parameters involved in the dynamic model of the crystallization, relating primary and secondary nucleation in particular, are subject to significant variations. In order to avoid any estimation divergence, an on-line parameter identification algorithm was added to the observer.Assuming that measurements of the nuclei particles are available, the observer is shown to provide a discretized reconstruction of the entire CSD which can be used for control purposes or process supervision.

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Turbidimetric method for on-line determination of latex particle number and particle size distribution

Cited by 64 publications

References 6 publications

Highly integrated optical microsystem for particle concentration measurement

Highly integrated optical microsystem for particle concentration measurement

Polymerization Online Monitoring

Nonlinear observer of crystal‐size distribution during batch crystallization

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