Digital control method and system thereof for solution replenishment system in the pad dyeing process with combination dyes

A digital control method for a solution replenishment system in a pad dyeing process with combination dyes, comprising:

• accurately calculating a real-time addition amount of each dye in the solution replenishment system in a whole dyeing process based on an initial dyeing rate of each dye, and replenishing a dye solution according to the real-time addition amount;
• wherein during the color combination pad dyeing process, an initial dyeing time of fabric dipping in the dye solution is 4s-6s, a dyeing rate K0,n of each dye remains unchanged in the initial dyeing time, K0,n is an initial dyeing rate of an n-th dye in the dyeing process, n≥1, and a number of dye types ≥2, the time of the fabric dipping the dye solution in the pad dyeing tank is t, and an amount of the dye mt,n adsorbed to the fabric per unit gram at t is:
• m
• t
• ,
• n
• =
• t
• 60
• ×
• K
• 0
• ,
• n
• ;
• in the formula, a unit of mt,n is mg·g−1;
• a unit of t is s;
• a unit of K0,n is mg·g−1·min−1;
• wherein a calculation method of the initial dyeing rate K0,n of each dye comprises the following steps:
• through a Raman spectrometer, a spectrophotometer or a liquid chromatograph, detecting changes of a concentration of each dye in a formula dye solution along with a dyeing time under color combination dyeing conditions, calculating the amount of each dye on a fabric per unit mass according to the concentration of each dye at corresponding dyeing times in the dye solution, drawing a curve graph of the dyeing process, and obtaining a slope of a zero point from the fitted curve graph of the dyeing process as the initial dyeing rate K0,n;
• in the pad dyeing process, after dyeing for T time, the amount of the dye mT,n adsorbed to the fabric is:
• mT,n=mt,n×T×X;
• in the formula, X is a weight of the dyed fabric per unit time;
• a unit of mT,n is g;
• a unit of T is min;
• a unit of X is g/min;
• Lr=Lp;
• in the formula, Lr is a volume of the replenishment solution with unit of mL;
• Lp is a volume of the dye solution rolled onto the fabric through pad dyeing with unit of mL;
• mr,n=mp,n+mT,n;
• in the formula, mT,n is a mass of the n-th component dye that needs to be added after dyeing for T time with unit of g;
• mp,n is a mass of the n-th component dye that rolled onto the fabric by a roller after dyeing for T time with unit of g;
• m
• r
• ,
• n
• =
• TX
• [
• C
• n
• (
• P
• -
• K
• 0
• ,
• 1
• ⁢
• t
• 6
• ×
• 10
• 4
• -
• K
• 0
• ,
• 2
• ⁢
• t
• 6
• ×
• 10
• 4
• -
• …
• -
• K
• 0
• ,
• n
• ⁢
• t
• 6
• ×
• 10
• 4
• )
• /
• ρ
• 0
• +
• K
• 0
• ,
• n
• ⁢
• t
• 6
• ×
• 10
• 4
• ]
• ;
• wherein Cn is an initial concentration of each dye in the dye solution with unit of g/mL;
• ρ0 is a density of an initial pad dyeing solution with unit of g/mL;
• P is a solution carrying rate of the fabric with unit of %;
• wherein the accuracy refers to real-time addition grams of each dye in the combination dyes.