System for monitoring contaminants with a detector in a paper pulp stream
First Claim
1. A system for monitoring a stock stream of paper pulp in a flow line for continuously monitoring contaminanats in said stream, comprising means coupled to the flow line for continuously withdrawing a sample stream of the stock stream at a point of significant reject concentrations, concentrating means for treating said sample to separate said pulp sample into a plurality of classified sample streams wherein at least one of said classified sample streams includes a concentration of the contaminant particles, and monitoring means to monitor said stream and determine the realtive level of the different contaminants in said monitored classified sample stream, said monitoring means including a dispersal flow means having a relatively wide and thin passageway means receiving said classified sample stream means to supply said classified sample stream to said passageway means at a flow rate establishing an essentially free flowing stream having a maximum level in said passageway means and an open space above said maximum level of said free flowing stream, and photodetector sensing means coupled to said free flowing stream to detect the contaminants therein.
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Abstract
In a contaminant detector for processing paper pulp including sticky contaminants, a pulp sample is diluted to less than 0.5% consistency and passed through a concentrator from a plurality of classified samples having heavy and light particles. The inclined classified samples are again diluted to less than 0.5% consistency and passed as thin sample flow through an open channel having a light transmitting base. The flow is back lighted and a photodetector includes a linear array of sensitive elements aligned to receive the transmitted light. The sensitive elements aligned with particle creates a signal proportional to the width. By rapid sequential activation of the elements, a digital data stream is created which is processed by a microprocessor to determine the particle size and produce a plurality of contaminant relative signals related to different classified size ranges, such as heavy, medium and small contaminant particles. A particle removal includes sequential stages for successively removing the heavy, medium and small sized contaminants, with a control for each stage. The pulp sample is taken at a highest concentration location and the contaminant related signals are connected to actuate the corresponding controls for the several stages.
57 Citations
20 Claims
- 1. A system for monitoring a stock stream of paper pulp in a flow line for continuously monitoring contaminanats in said stream, comprising means coupled to the flow line for continuously withdrawing a sample stream of the stock stream at a point of significant reject concentrations, concentrating means for treating said sample to separate said pulp sample into a plurality of classified sample streams wherein at least one of said classified sample streams includes a concentration of the contaminant particles, and monitoring means to monitor said stream and determine the realtive level of the different contaminants in said monitored classified sample stream, said monitoring means including a dispersal flow means having a relatively wide and thin passageway means receiving said classified sample stream means to supply said classified sample stream to said passageway means at a flow rate establishing an essentially free flowing stream having a maximum level in said passageway means and an open space above said maximum level of said free flowing stream, and photodetector sensing means coupled to said free flowing stream to detect the contaminants therein.
- 12. A waste paper pulp porcessing apparatus for monitoring the changes in contaminant levels in pulp stream, comprising a sample means for withdrawing a pulp sample from said pulp stream, a separating means connected to said sample means for separating from said sample a contaminant portion of the sample essentially free of paper forming fibers and having a substantial portion of selected contaminants of said pulp sample, a dispersal flow means having a relatively wide and thin flow passageway, means to supply said classified sample stream to said passageway at a flow rate establishing an essentially free sheet-like flowing stream of said contaminant portion of the sample in said passageway, having a maximum level in said passageway and an open space above said maximum level of said free flowing stream, a photodetector means adjacent said passageway having a linear array of photosensitive element located across said passageway and establishing adjacent sensing areas on the order of micrometers, and back lighting means located to the opposite side of the passageway from said linear array of phtosensitive elements.
Specification