Pulp bleaching process control using photocells to measure pulp

Details Pulp bleaching process control using photocells to measure pulp Pulp bleaching process control using photocells to measure pulp

1975-02-03

1976-07-06

Bashore, S. Leon

Paper making and fiber liberation

Processes and products

With measuring, inspecting and/or testing

162238, 162 49, 162DIG10, 250576, 338 15, 338 19, 356181, D21C 910, D21C 912

Patent

active

039680061

ABSTRACT:
To achieve constant brightness from the chlorine stage of a wood pulp bleaching system, the chlorine addition rate is controlled by two white light photosensors positioned, respectively, 1-5 minutes downstream of the chlorine addition point and immediately prior to the chlorine washers. A relative error signal from the late photosensor is cascaded upon the set-point of a signal differentiator for the early photosensor to generate a chlorine valve control signal. The photosensors comprise selenium photocells positioned against a transparent stock conduit window and reflection illuminated by a low power white light source positioned more remotely from the window than the photocell at a discreet offset angle relative thereto. The white light is directed past the photocells, through the windows and into the flow stream; the photocells being responsive to the relative magnitude of white light reflected from the wood pulp. The power generated from the photocell is correlated to the pulp brightness.

REFERENCES:
patent: 1935698 (1931-08-01), Decker et al.
patent: 3465550 (1969-09-01), Strom et al.
patent: 3773424 (1973-11-01), Selgin
obenshain, "Black Widow Bleaching Control System," pp. 1-9, TAPPI, vol. 41, No. 1, Jan. 1958.
Burnett; "Computer Control of the Chlorine Stage," pp. 57-62, Pulp and Paper Magazine of Canada, vol. 71, No. 14, July 17, 1970.
Robinson et al.; "A Computer Control System for a Multi-Stage Bleach Plant," Paper Trade Journal, May 14, 1973.
U.S. Published Patent Application, B300,004, Putman, "Computer Control System for Paper Pulp Bleach Plant," Jan. 28, 1975.
Shera; "Systems Compatibility for ORP Pulp Chlorination Control," TAPPI; vol. 50, No. 2, pp. 99a-103a, Feb. 1967.

Affiliated with

Also associated with

Rating

Pulp bleaching process control using photocells to measure pulp does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Pulp bleaching process control using photocells to measure pulp , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pulp bleaching process control using photocells to measure pulp will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1531900