Shive ratio analyzer

An apparatus for determining the relative presence of shives in a production flow stream of paper pulp slurry, said apparatus comprising:

• A. sample extraction means for continuously extracting a sample flow of said paper pulp slurry from within a pressurized conduit carrying said production flow stream,
• said sample extraction means comprises means to form relatively high velocity jet of fiber-free water across a transversely disposed gap within said production flow stream into a receiving end of said sample conduit means to induct a fraction of said pulp slurry thereinto;
• B. sample conduit means for delivering said sample flow through a photodetection window;
• C. photodetection means comprising a light source and a light sensor operatively disposed on opposite sides of said window for generating a composite first signal having a variable amplitude pulsing constitutent responsive to the passage of fiber particles through said window, the amplitude of individual pulses being proportional to the size of respective, individual particles;
• D. signal filter means for segregating said pulsing constitutent of said first signal form an average d.c. value thereof and transmitting said pulsing constituent as a second signal;
• E. comparative discriminator means responsive to said second signal to generate a third signal pulse flow wherein each third signal pulse corresponds to a second signal pulse having an amplitude corresponding to a shive size particle in said sample flow;
• F. first pulse counting means for cyclically determining the number of second signal pulses received thereby in a fixed time interval and emitting a cyclically adjusted first rate signal proportional to the time flow rate of said second signal pulses;
• G. second pulse counting means for cyclically determining the number of said third signal pulses received thereby in said fixed time interval and emitting a cyclically adjusted second rate signal proportional to the time flow rate of said third signal pulses;
• and
• H. signal ratio means for combining said first and second rate signals to derive a relative proportionality therebetween and emit a signal proportional to said relative proportionality.

An apparatus for determining the relative presence of shives within a paper pulp slurry of 0.1% consistency or less comprising:

• A. A conduit having a transparent photodetector window for carrying a flow stream of said slurry therethrough;
• B. A photodetection cell comprising a light source and light sensor for generating a first electric signal responsive to the quantity of source light received by said sensor after passing through said window and a flow stream of said slurry therein;
• C. Signal filter means for segregating variable amplitude pulse components of said first signal from an average d.c. value of said first signal and transmitting said variable amplitude pulse component as a second signal, said variable amplitude pulses being derived from the presence of particulates in said slurry flowing past said window and blocking the incidence of light on said sensor, the amplitude of each pulse being directly proportional to the size of the respective particle;
• D. Comparative discriminator means responsive to said second signal to generate a third signal pulse for each pulse in said second signal having an amplitude exceeding a predetermined reference value distinctive to a shive particle;
• E. First pulse counting means for counting a predetermined number of second signal pulses received thereby and emitting a gate signal upon arrival at said predetermined number;
• F. Second pulse counting means for counting the number of third signal pulses received thereby in a counting interim, said counted number of third signal pulses representing a ratio value of the number of shive partilces per predetermined number of slurry particles, said second pulse counting means including fourth signal means for emitting a fourth signal proportional to said ratio value;
• and
• G. Means responsive to said gate signal to terminate said counting interim and reset said first and second pulse counting means to a count reference point.