An experiment has been made to determine the weft velocity and hydraulic pressure in weft insertion. The experimental observation has analyzed the factors affecting on the time required for weft insertion and the behaviour of flying yarn. Using the weft tension caused with the jet of air, the equation of flying motion of a weft yarn has been derivec, through which the weft velocity (W), insert length (X), time required for weft insertion (t) and force applied on weft end caused with jet of air (T) have been calculated. These calculated values coincide well with the experimental values. It is concludad that the greater the difference between weft velocity and jet velocity around the flying weft, the more stable the weft insertion.

View full abstract

When a fiber assembly such as cloth or yarn is washed, a chemical to be washed off from fiber assembly migrates in fiber phase and also water phase in a fiber assembly and subsequently transfers to water.
In such processes the diffusion coefficient of a chemical agent in a fiber differs largely from that in water. These processes were analyzed on the basis of a diffusion theory. Assuming that a single fiber is a column and a fiber assembly is a column or a plane, the following theoretical relations, representing residual fraction of a chemical agent in a fiber assembly during washing, were obtained :
y(t) =(∞Σi=1)(∞Σj=1)A_ijexp (-D_fμ_ij²/R²t)
where, t; washingtime (s)
y(t); residual fraction of a chemical in a fiberassembly
D_f; diffusion coefficient of a chemical in a fiber (cm²/s)
R; radiusoffiber (cm)
A_ij= (2Q_i/ (1+α) β²μ_ij²) ²1/1+α/1+αJ₁² (μ_ij) /J₀² (μ_ij) (column)
A_ij=1/2 (2Q_i/ (1+α) β²μ_ij²) ²1+α/1+αJ₁² (μ_ij) /J₀² (μ_ij) (plane)
Q_i;roots J₀ (Q_i) =0(column)
roots of cos (Q_i) =0 (plane)
μ_ij;roots of Q_i=βμ_ij√1+α2J₁ (μ_ij) /μ_ijJ₀ (μ_ij)
J₀, J₁ : Bessel functions of order 0 and 1
α, β : constants depending on a diffusion coefficient of a chemical in a fiber and water, geometrical characteristics of a fiber assembly and so on.
The theoretical results calculated by using the above equations agree closely with the experimental values and also very closely with the results obtained using the simplified equation on which we had previously reported.

View full abstract