Rieter

Definitions

Index

The noil theory developed by Charles Gégauff and described below provides a picture of the effects of detachment setting and feed distance moved per cycle on the elimination of noil. The word „picture“ is used quite deliberately in this connection, since the theory does not allow anything more exact.

However, it does show the correlation between feed amount and noil percentage with either forward or backward feeding, i.e. why it differs. However, calculations made on the basis of the theory are often intractable and should therefore not be attempted. Symbols used in these explanations* have the following meanings: (Z to E belonging to Fig. 13, s to p belonging to Fig. 14-17)

Z
nippers;
A
detaching rollers;
B
fiber fringe protruding from the nippers;
K
combing segment;
E
detachment setting, i.e. distance between the clamping line of the nippers and the nip line of the detaching rollers;
S
feed amount (mm) moved per combing cycle;
M
longest fiber in the staple (mm);
a
fiber ≥ E;
b
fiber = E - S;
c
fiber < E - S;
p
noil percentage.

Forward feed implies that feeding of the sheet into the nippers occurs while the nippers are moved toward the detaching rollers.

Backward feed implies that feeding of the sheet occurs during return of the nippers. The triangular areas represent stylized staple diagrams.

*The subsequent presentation of the theory is based upon information supplied by the Rieter Company and on H. B. Wolf in “Baumwollspinnerei”.

Fig. 13 – Position of the nippers relative to the detaching rollers at the closest approach (detachment setting E) during backward feed

Fig. 14 – Combing out with backward feed (the staple diagram is shown)

Fig. 15 – Combing out the fi ber fringe

Fig. 16 – Position of the nippers relative to the detaching rollers at the closest approach during forward feed

Fig. 17 – Combing out with forward feed (staple diagram).