Non-invasive method and low-coherence apparatus system analysis and process control

A method for determining the size for particles of a known concentration in a stream of colloidal or particulate suspension comprising the steps of:

• illuminating both a sample of the stream and a reference with a common level of low-coherent electromagnetic radiation;
• combining resultant reflected radiation from said sample and said reference to provide an interference signal;
• determining photon pathlength distribution of said sample;
• and
• obtaining the particle size from the interference signal using a fitting procedure to obtain the scattering and absorption coefficients.

A method for monitoring and control of an optical property comprising the steps of:

• illuminating both a sample of the stream and a reference with a common level of low-coherent electromagnetic radiation;
• combining resultant reflected radiation from said sample and said reference to provide an interference signal and,
• determining photon pathlength distribution of said sample from the interference signal and a processor responsive to the pathlength distribution and a processor device that compares the measured signal with a prescribed signal;
• and
• an output device to update an estimation signal as compared with the comparison signal.

A process control apparatus useful comprising;

• a reference probe and at least one sample probe positioned in a flow channel for a stream of colloidal or particulate suspensions;
• at least one low-coherence light source;
• means for illuminating the reference probe and sample probe with a split beam of electromagnetic radiation;
• means for converting the photon pathlength distribution of an interference signal into particulate size data;
• and
• means for modifying the particulate size of said stream.

A particle sizing apparatus comprising:

• a reference probe and at least one sample probe positioned in the flow channel for a stream of colloidal or particulate suspended materials;
• at least one low-coherence light source;
• means for providing a split beam of electromagnetic radiation capable of illuminating a sample probe positioned in said stream and a reference probe;
• means for combining the reflected illuminations from said probes to provide an interference signal;
• particulate density means for converting the photon pathlength distribution of said interference signal into the particulate density of the stream;
• and,
• means for adjusting the particulate density of the stream.