Abstract: The present invention relates to a device and method for measuring the bleach requirement and bleachability of pulp in a pulp mill. The invention enables pulp mill operators to better control bleach plants. In one aspect, the invention comprises a system and method for rapid bleaching of the pulp, and measuring the rapid bleached brightness and lignin content of the pulp. In another aspect, the invention comprises an optical system for use in practicing embodiments of this invention.

Abstract: A device for obtaining a sample of fiber from an aqueous slurry of fiber flowing through a stock line, comprising a first isolation inlet valve element together with a water supply orifice, located inside a fiber stock line; a second isolation valve means, and a third isolation valve, mounted in flow series from the sample inlet point on the stock line. This device allows a complete water purging down through the inlet valve element, as well as fiber samples to flow out of the stock line in the presence of diluent water. Samples flow from the first isolation valve means to a final collection point, without contamination or plugging.