Appeal No. 1998-1053
Application No. 07/974,832
derive respective density and pressure measurements and
estimating a current target pressure of foamed furnish in said
headbox based substantially exclusively upon: said parameter
determinative of the velocity of said moving foraminous
support; said measurements of density and pressure; the
density of the liquid phase; and the difference in height
between said jet and said location in said headbox at which
the pressure of the foamed furnish in the headbox is measured;
and
comparing the estimated current target pressure of the
foamed furnish in the headbox with a parameter derived from
said density measurement and said pressure measurements and
controlling said feeding step to move the estimated current
target pressure in the headbox and the headbox pressure
measurement closer to each other.
CLAIM 36
A method of controlling a jet of foamed furnish leaving a
pressurized headbox of a paper or a tissue making machine
comprising the steps of:
feeding foamed furnish to a pressurized headbox to form a
jet of said furnish;
measuring parameters determinative of the density and
pressure of the foamed furnish;
estimating a parameter related to a current target
pressure of the foamed furnish in the headbox, said estimating
consisting essentially of using the measurements determinative
of density and pressure;
comparing the measurement determinative of pressure in
the headbox with the parameter related to current target
pressure in the headbox to derive a control signal; and
utilizing the control signal to control the feeding step
to vary the measurement determinative of pressure in the
headbox to the parameter determinative of current target
A-5
Page: Previous 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Next
Last modified: November 3, 2007