On-line sensor for colloidal substances

A method for controlling a process parameter of a process involving a colloidal mixture comprising the steps of:

• providing at least a first portion of the colloidal mixture for an optical measurement by the steps of:
• providing a portion of the colloidal mixture to an in-line centrifuge unit to separate particulate matter therefrom, to obtain an approximately fiber-free sample;
• and
• providing the approximately fiber-free sample as the at least a first portion;
• determining a value indicative of a characteristic of the colloidal mixture by the steps of:
• irradiating the at least a first portion of the colloidal mixture with light in an ultraviolet-visible region at a first temperature and obtaining a first measurement of a first wavelength within the ultraviolet-visible region, said first measurement for obtaining a measure of one of an absorption, emission and scattering of the first wavelength when said colloidal mixture is irradiated with the light;
• waiting for the temperature of the colloidal mixture to change;
• irradiating the at least a first portion of the colloidal mixture with light in an ultraviolet-visible region at a second different temperature and obtaining a second measurement of the first wavelength within the ultraviolet-visible region, said second measurement for obtaining a measure of one of an absorption, emission and scattering of the first wavelength when said colloidal mixture is irradiated with the light;
• and
• determining the value indicative of the characteristic of the colloidal mixture from a relationship including including the first measurement and the second measurement;
• determining, in dependence upon the determined value, an adjustment to the process parameter of the process involving the colloidal mixture;
• providing to an automated controller of the process involving the colloidal mixture a feedback signal in dependence upon the determined adjustment;
• and adjusting automatically the process parameter of the process in dependence upon the provided feedback signal.

A method for controlling a characteristic of a colloidal mixture comprising the steps of:

• providing a colloidal mixture for analysis by thermal difference spectroscopy;
• determining a value indicative of the characteristic of the colloidal mixture by the steps of:
• irradiating at least a first portion of the colloidal mixture with light in an ultraviolet-visible region at a first temperature and obtaining at least a first measurement of a first and a second wavelength within the ultraviolet-visible region, said first measurement for obtaining one of an absorption, emission and scattering of the first wavelength when said colloidal mixture is irradiated with the light,
• waiting for the temperature of the colloidal mixture to change,
• irradiating at least a second portion of the colloidal mixture with light in an ultraviolet-visible region at a second different temperature and obtaining at least a second measurement of the first and the second wavelength within the ultraviolet-visible region, said second measurement for obtaining one of an absorption, emission and scattering of the second wavelength when said colloidal mixture is irradiated with the light, and
• determining the value indicative of the characteristic of the colloidal mixture from a relationship including a ratio of the at least first and second measurement;
• determining, in dependence upon the determined value, an adjustment to at least a variable of a control process for affecting at least a characteristic of the colloidal mixture;
• providing a feedback signal in dependence upon the determined adjustment to an automated controller of the control process;
• and
• adjusting automatically the variable of the control process in dependence upon the provided feedback signal.

An on-line optical sensor apparatus for controlling a process parameter of a process involving a colloidal mixture comprising:

• an in-line centrifuge unit for separating fiber from the colloidal mixture to obtain an approximately fiber-free liquid sample;
• a detector for obtaining a first measurement and a second measurement of light in an ultraviolet-visible region, said first measurement for obtaining a measure of one of an absorption, emission and scattering of at least a first wavelength of the light at a first temperature when the approximately fiber-free liquid sample of the colloidal mixture is irradiated with the light, and said second measurement for obtaining a measure of one of an absorption, emission and scattering of the first wavelength of the light at a second different temperature when the approximately fiber-free liquid sample of the colloidal mixture is irradiated with the light;
• and
• a suitably programmed processor in electrical communication with an automated process controller for providing thereto a signal indicative of an adjustment to the process parameter, wherein said adjustment is determined in dependence upon a characteristic of the colloidal mixture, and wherein said characteristic of the colloidal mixture is determined from a relationship including the first and second measurement.