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US 4,952,280 AGranted
Process for controlling the addition of retention aids in papermaking
AssigneeBASF SE
InventorsRalf Hemel, Jaroslav Melzer
Life of this patent
Estimating the term…
Abstract
The maximum amounts of the retention-influencing variable stock components which can be added are determined as a function of a predetermined degree of flocculation and typical values of the stock suspension with the aid of a mathematical relationship, and control signals for metering retention aids are derived from the amounts so that the greatest possible retention can be achieved without exceeding a set-point for the degree of flocculation.
Claims1
A process for controlling the addition of retention aids in papermaking, which comprises:
- (a) determining a set-point degree of flocculation of a stock suspension;
- (b) measuring the retention and degree of flocculation of a stock suspension;
- (c) determining the effect of variable stock values (X.sub.1, . . . X.sub.n), on the retention and the degree of flocculation with the aid of statistical methods;
- (d) using the determined effect of stock values to set up empirical equations:
- Y.sub.1 =f.sub.1 (X.sub.1, . . . X.sub.i, . . . X.sub.n);
- (I)
- and
- Y.sub.2 =f.sub.2 (X.sub.1, . . . X.sub.i, . . . X.sub.n);
- (II)
- where Y.sub.1 represents the total retention and Y.sub.2 represents the set-point degree of flocculation;
- (e) storing the empirical equations as a control algorithm in a computer;
- (f) continuously inputting measured data of the stock values to the computer so that a maximum amount of retention-influencing stock components can be determined;
- and
- (g) sending control signals from the computer to a metering apparatus to control the input of retention aids so that the greatest possible retention can be achieved without exceeding the set-point degree of flocculation.
11 more elements
Dependencies are inferred from the claim text.