Fiber length indicating apparatus and method

On line apparatus for periodic testing of the length of fibers in paper stock or pulp flowing in a paper making system while pressurized, undiluted and at paper making consistencies, and of predetermined relative length said apparatus comprising:

• an upstanding container having a lower end connected into said paper making system to receive said stock, or pulp, at operating consistency, pressurized, undiluted, and of predetermined relative fiber length the interior of said container being thereby incorporated into said paper making system;
• an orifice plate mounted across the interior of said container, intermediate of the height thereof to form a measuring chamber thereabove, said plate being imperforate except for at least one orifice therethrough and up to about five identical said orifices therethrough each with a rim extending therearound, each said orifice being circular in configuration and of predetermined area with a diameter substantially equal to the predetermined relative length of said stock, or pulp, in said system, the diameter of said circular orifice being in the range between 1 mm and 20 mm;
• liquid level sensing means in said measurement chamber for sensing liquid level reached therein by said undiluted stock, or pulp, at operating consistency;
• automatic control means including a cycle timer operably connected to said measurement chamber for periodically cycling said chamber through intake, measure and exhaust, and establishing a set intake time for said predetermined relative fiber length;
• means for periodically and instantaneously generating a signal representing relative fiber length in stock, or pulp, in said paper stock, or pulp system;
• said control means including said means for generating a signal for signalling fiber length sensed during each said cycle.

The on line method of automatically, periodically testing the length of fibers in refined, or unrefined, paper fiber slurry while in a paper making system and while pressurized, undiluted at operating consistencies and of predetermined relative fiber length, by means of a standpipe connected into said system, the standpipe having an orifice plate extending across the interior thereof with at least one circular orifice therein, and obtaining an instantaneous read out of said fiber length, said method comprising the steps of:

• selecting as said plate of imperforate material having at least one circular orifice and up to about five identical said orifices, each of predetermined area and diameter substantially equal to the predetermined relative length of the fibers in said system, said diameter being in the range of 1 mm to 20 mm;
• connecting said standpipe on line into said system for an intake, measure and exhaust cycle wherein said slurry must pass from said system through said circular orifice into a measurement chamber;
• establishing a set intake time for measurement in said chamber for the said predetermined relative length of fibers;
• measuring during each intake cycle, in comparison with said set intake time, whether said slurry passes through said orifice into said measurement chamber, in a predetermined volume or to a predetermined height therein;
• and periodically, instantaneously generating a signal representing the relative fiber length in said slurry.

On line apparatus for controlling the quality of paper stock discharged from stock refiners, said apparatus comprising:

• a paper stock supply system containing pressurized, undiluted stock at normal operating consistency and including a stock refiner having a pair of members rotatably movable relative to each other;
• means for driving one of said members with respect to the other member;
• means for changing the refining effect of said refiner;
• on line fiber length indicating means connected into said stock supply system for periodically measuring the relative length of the fibers in the stock passing through said system, said means including a plate of imperforate material having a substantially cylindrical aperture with a diameter in the range of 1 mm to 20 mm and substantially equal to the predetermined relative length of fibers to be refined, means for sensing the time of passage of stock through said aperture as compared to a predetermined time interval;
• means for periodically, instantaneously generating a signal representing relative fiber length in said stock;
• and control means for operatively connecting said sensing means, said means for generating a signal, and said measuring means with said means for changing the refining effect of said refiner to compensate for any variations of length of fiber supplied thereto with the predetermined relative length of fiber supplied thereto.

Apparatus for periodic testing of the length of fibers in paper stock or pulp in a supply thereof of predetermined relative fiber length, said apparatus comprising:

• an upstanding stock container having a lower end connected to said supply of paper stock, or pulp, of predetermined relative fiber length, a stock chamber having a lower portion and an upper portion, liquid level sensing means within the upper portion of said chamber for sensing the time of arrival of stock levels therein;
• an orifice plate mounted across said chamber to divide said chamber into said upper and lower portions, said plate being imperforate except for having one to five identical, circular orifices therethrough, each of predetermined diameter equal to the said predetermined relative length of the fibers in said stock or pulp, each said identical circular orifice having an identical diameter in the range of, one to twenty millimeters;
• automatic control means, operably connected to said container for periodically cycling said chamber through intake measure and exhaust of said stock or pulp;
• means for periodically, instantaneously generating a signal representing relative fiber length in said stock or pulp in said supply;
• and automatic timing means connected to said liquid level sensing means and to said means for generating a signal for displaying the value of stock accumulation in said upper portion of said chamber during a pre-set period of time.