GB1568148A - Method of producing cheeses - Google Patents

Description

(54) A METHOD OF PRODUCING CHEESES (71) We, BAYER AKTIEN GSELLSCHAFT, a body corporate organised under the laws of Germany of, 509 Leverkusen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method of producing cheeses from natural or synthetic, drawn or undrawn filaments, in which the formation of mirror or constant pattern windings is reduced.

So-called random wound cheeses are known in which constant pattern or mirror windings occur at certain diameters, i.e. the mutual position of individual filaments changes from layers in which the filaments are neither parallel nore situated one above the other to layers in which the filaments are parallel to and situated above one another.

This winding fault is also called constant pattern winding or ribbon winding.

In so-called precision wound cheeses, the filaments lie adjacent one another by virtue of the linear winding ratio and the v-value and the filaments of every second layer are parallel to one another.

If the arrangement of individual filaments relative to one another is observed, a certain similarity is found between the mirror or constant pattern windings in random wound cheeses and precision-wound cheeses. Both in random winding and also in precision winding, the filaments of every second layer are parallel to one another in the most simple case. In the case of precision-wound cheeses, the intervals between the centres of two adjacent filaments are displaced relative to one another by the v-value to such an extent that, although they are parallel to one another, they are not situated above one another. In the case of constant pattern or ribbon winding, the filaments of every second layer are parallel to and above one another in the most simple case.

However, this layer structure, which is characteristic of random wound cheeses, may be regarded as theoretically simplified by comparison with structures found in practice because, in addition to layers of filaments lying parallel to and above one another, there are also layers which lie parallel to and adjacent one another both on account of the continuous change in the diameter of the cheese during winding and on account of slipping or sliding of the individual layers of filaments.

A precision wound cheese may be regarded as homogeneous. A random wound cheese may be regarded as inhomogeneous when the zones with and without constant pattern winding are compared with one another. This inhomogeneity is responsible for the fact that, in random wound cheeses, individual zones of the cheese can be displaced relative to one another, especially when certain properties of the filament vary over the length of the filament. This is generally the case in practice.

In order to avoid the adverse effects of constant pattern or ribbon windings, socalled jammers are used in practice. For example, an interfering frequency is superimposed upon the constant traversing frequency. Although jammers such as these improve the cohesion of the cheese, they do not avoid constant pattern windings. The constant pattern windings are merely distributed over a wider area.

Cheeses with a disturbed random winding have a sufficiently firm structure, even in the case of smooth man-made filaments.

Unfortunately, the offwinding properties of cheeses such as these are extremely unsatisfactory at high overhead offwinding speeds, for example in excess of 400 m/minute. This is particularly the case in processes where the filament is subjected to mechanical and/or thermal stressing, for example during cold drawing, hot drawing, draw-texturing (simultaneous or consecutive) or fixing. Thus, corresponding drawing tests, in which the filament is offwound overhead at high speeds from a cheese with a disturbed random winding, show that the number of filament breakages is particularly high at certain cheese diameters (Example 1, Figure 1).

In Figure 1, the number of filament breakages (ordinate) is plotted against the particular package diameter or package radius (abscissa). The offwinding speed at the drawing stage is 2500 minute. The Roman numerals denote the order of the mirror winding.

An object of the present invention is to obviate the disadvantages referred to above, i.e. to produce cheeses of which the offwinding properties are satisfactory, even at high offwinding speeds.

According to the invention, there is provided a winding process for producing cheeses from natural or synthetic, drawn or undrawn filaments, wherein the traversing frequency DH of the thread guide is controlled as a function of time or a time dependent parameter in such a way that the absolute value of the change in n relative to the change in the radius r of the cheese where n=f (r, DH) and is the ratio of the rotational frequency of the cheese to the traversing frequency of the filament guide member) is greater than the absolute value of the change in n as a function of the radius r of the cheese at a constant traversing frequency of the filament guide member and hence complies with the relation: |dn| |dr| when DH is variable |dn| > |dr| when DH is constant.(I) The coefficient of increase of the traversing frequency of the thread guide is preferably greater than zero. The coefficient of increase d DH dr may assume any values which are greater than zero and smaller than the maximum rate of increase of the traversing frequency of the particular winding machine.

Thus dH > 0 (2) dr The process according to the invention also includes controlling the winding process to produce cheeses in accordance with expression (2).

Embodiments of the process according to the invention are carried out in accordance with the following functions, as will be explained further below:

In order to explain the parameters used to characterise the process, the background to the process according to the invention is discussed in more detail in the following with reference to the Figures.

In Figures 2 to 4, n i.e. the ratio between the rotational frequency of the cheese and the traversing frequency DH, is recorded on the ordinate, whilst the radius r of the cheese is recorded on the abscissa.

In Figures 6 and 7, the traversing frequency DH (number of traversing double strokes) is recorded on the ordinate and the radius r on the abscissa.

Further explanations of the Figures are given in the following description.

As can be seen from Example 1, the diameter of cheeses at which filament breakages occur with particularly high probability as a result of disturbances in the offwinding process, may be calculated in accordance with the following expression: v m ~=DH (3) 2nr k k=l, 2, 3, .

m=k, k+l, k+2, . . ., nk, .

v=linear winding speed of the cheese in cm/minute.

r=radius of the cheese during winding in cm.

DH=number of double strokes per minute if m -=n k then (3) changes to (4): v =n DH (4) 2nr In the two-dimensional representation of n as a function of v for a certain winding speed v and with the traversing frequency DH as the representation parameter, hyperbolae are obtained (Figure 2). The offwinding speed v was 800 m/min~1.

At the cheese diameters at the points of intersection of the hyperbolae with a straight line n=const., which correspond to a low constant pattern (ribbon) winding order, constant pattern or mirror windings occur and lead with particularly high probability to offwinding difficulties and hence to filament breakages.

At high offwinding speeds of the filament from the cheese, the offwinding difficulties are particularly noticeable (Example 2).

In mathematical terms, the straight lines n=const., the hyperbolae n=f (r) and their points of intersection are dimensionless (no spatial or planar character). However, in the case of cheeses produced at a constant traversing frequency, it is found that the mirror or constant pattern windings occur over a radius zone, although only a "radius point" can be calculated according to (3) or (4).

The discovery that mirror or constant pattern windings do not occur at a point, but instead over a radius zone, may be illustrated by the fact that the straight lines n=const. in Fig. 2 are replaced by bands (Figure 3).

If the bands in Fig. 3 are imagined as being surfaces defined by two straight parallel lines, the radius zones in which mirror or constant pattern windings occur correspond to the differences between the abscissa values of the intersections of the hyperbolae n=f (r) with the straight lines defining the bands (for example Arl, Ar2, and Ar3 in Figure 3). It must be assumed that the probability of difficulties in offwinding the filament from the cheese is dependent upon the size of the mirror or constant pattern winding zone, i.e. the greater (or smaller) the mirror winding zone, the greater (or smaller) the probability of filament breakage attributable to offwinding difficulties.

In the process according to the invention, a reduction in the mirror or constant pattern winding zones, such as those which occur in a winding process carried out at a constant traversing frequency, is obtained by controlling the traversing frequency in accordance with expression (1) or (2).

If we consider for example point A from Figure 3, which is shown on a larger scale in Fig. 4, it can be seen that, for a given band width, the size of the mirror or constant pattern winding zone r is determined by the value of the coefficient of increase of the function n=f (r).

Curve I (Fig. 4) applies to a winding process carried out at a constant traversing speed DH. The straight lines by which the band is defined are intersected at the points P, and P2.

The mirror or constant pattern winding zone corresponds to the difference between the abscissa values of the intersections P2 and P1; Ar1=r2-r1.

In a winding process corresponding to curve II, for example, the mirror or constant pattern winding zone is determined by the difference between the abscissa values of the intersections P4 and P3; Ar11=r4-r3.

A comparison of the coefficients of increase of curves I and II produces expression (1).

If the winding process could be controlled along a straight line parallel to the ordinate, the mirror or constant pattern winding zone would be equal to zero. This situation cannot be achieved in practice, nor would there by any sense in it, because in that case the winding process would have to be carried out at a constant radius.

The coefficient of increase of curve II (Fig. 4) has a negative sign:

The coefficient of increase of curve III (Fig. 4) is positive:

If the absolute values of the coefficients of increase of curves II and III are the same, as shown in Figure 4, both curves produce equally large mirror or constant pattern winding zones; in the case of curve III, the mirror or constant pattern winding zone is equal to the difference between the abscissa values of the intersections P5 and P6.

The working zone of the possible winding processes (Fig. 5) is determined by, a) the straight line r=rO=initial radius of the cheese, b) the straight line r=rE=final radius of the cheese, c) the curve n=f (r) for DII=DIImin. DHm,n represents the lowest possible traversing frequency at which it is still possible to obtain a satisfactory cheese structure.

d) the curve n=f (r) for DH=DHmRI. DII max corresponds to the maximum possible traversing frequency which is determined, for example, by the technical layout of the winding machine, by the type of thread guide used or by the strength of the material to be wound.

Two possible control functions are shown in the predetermined working zone, namely g (r) and q (r). Both functions pass through the point [r(n=4, DH=300), n=4] and are selected in such a way that the absolute values of the coefficients of increase fulfil condition (1).

The form of the working zone means that the function n=q (r), which has a positive coefficient of increase, covers a smaller overall radius zone than the function g (r).

In practice, therefore, preference will generally be given to a function with negative coefficients of increase dn dr A control in accordance with a function analogous to q (r) (with a positive coefficient of increase) may, of course, also be applied in practice.

In the process according to the invention for the production of cheeses, condition (1) must be fulfilled. Functions in accordance with which the process for producing cheeses according to the invention can be controlled may be described by the following expression:

One possibility of applying the process according to the invention is to carry out the winding process in accordance with the following expressions: (nnO)=a(r-rO) (8) v DH= ---- [a(r-ro)+no]- (8a) 27#r The coefficient of increase a from (8) is determined by the starting and end points of the winding process: nE - nO a= (9) r6-r0 Another possibility of controlling the winding process is obtained from (1) and the complete differential of the function n=f (r, DH): v DHo DH= (9) nb DHO(r2rO2)+v v=linear winding speed DHO=initial traversing frequency rO=initial radius of the cheese DH=traversing frequency at the radius r r=radius during the winding process b=constant The constant b is determined from the starting point (ro, DHo) and the end point (rE, DHE) of the winding process:

If the available traversing range is to be fully utilised, b is determined as follows:

As can also be seen from Figure 3, it follows from expression 1 and the complte differential of the function n=f (r, DH) that d DH > 0 (2) dr when dn - < 0 dr and that d DH < 0 (12) dr when dn - > 0 dr In practice, it is more favourable to control the winding process in accordance with expression (2) than in accordance with expression (12) because a wider overall radius zone is covered in the first case.

These facts are illustrated in Figures 6 and 7.

In accordance with the explanations of Fig. 3, the hyperbolae in Fig. 6 had to be drawn in the form of bands.

If, for example, a cheese is produced with the thread guide traversing at a constant speed, the bands are intersected and a certain radius zone (for example Ar, #r2, Ar3), in which the mirror or constant pattern windings occur, corresponds to the particular length of intersection.

Figure 7, which illustrates a zone of intersection, shows that a positive coefficient of increase d DH > 0 dr of the traversing frequency relative to the radius leads to a reduction in the mirror or constant pattern winding zone when compared with the conditions prevailing during constant traversing.

The mirror or constant pattern winding band is intersected by the straight line DH=const. at the points P, and P2. The mirror or constant pattern winding zone is defined by the difference between the Ar=r2-r1.

If the winding process is controlled, for example, along the straight line I, the hyperbola band is intersected at the points P3 and P4 and the mirror winding zone corresponds to the difference of r4 and r3; Ar=r4-r2 The reduction in the mirror or constant pattern winding zone at I relative to DH=const. can readily be seen.

The straight line II represents the same mirror or constant pattern winding zone as the straight line I. However, since the absolute value of the coefficient of increase

of the line II is greater than that of the line I, the overall radius zone of a winding process is smaller than at I and, hence, of less interest in practice.

Controlling the winding process in accordance with expression (2) affords advantages in cases where it is desired to produce cheeses with the largest possible radii.

The following further possibility of controlling the winding process (Example 3) follows from the preceding considerations: DH-DH,=e (r-r,) (13) The constant c is determined from the starting point (rio, DHo) and the end point (rE, DHE): DHEDHo (14) rE - rO The largest value for c is obtained in cases where the points (rio, DHmin) and (rue, DHmax) are selected as the starting point and end point, respectively (Figure 6): DHmaxDHo Cmax= (14a) rE - rO Another possibility of controlling the winding process is obtained from expression 2 and the complete differential of the function DH=f (r, n): nH=1 r d (r2 - rio2) + rods (15) The constant d is determined from the starting point (rio, DHo) and end point (rue, DHE):

The largest value for d is obtained by selecting the points (r0, DIImin) and (rue, DHmax) as the starting point and end point, respectively:

In the process according to the invention, the production of cheeses may be controlled in accordance with any functions which fulfil condition (1) and which may be described by a polynomial:

In the process according to the invention cheeses may be produced either at an increasing traversing frequency or, providing a relatively smaller overall radius zone is accepted, at a decreasing traversing frequency.

The maximum positive or even negative degree of increase in the traversing frequency is determined by the technical layout of the traversing machine and, hence, cannot be numerically expressed because several different types of winding machines are available in practice.

In practice the maximum possible rate of increase in the traversing frequency is rarely used because in that case the advantages of the process would be limited to a small overall radius zone. Instead, the control function in the process according to the invention should be selected in such a way that the advantages afforded by the process according to the invention are used as uniformly as possible, based on the frequency of disturbances during offwinding, over the entire radius zone of the cheese. Determination of the control function should be preceded by an analysis of the filament breakage frequency. In order to obtain an improvement in offwinding of the filament from the cheese, it will not always be necessary to utilise the entire range of possible changes in the traversing frequency. It is best to work only with a difference in the traversing frequency which is just above that traversing difference which is required to obtain the desired improvement in unwinding of the cheese.

Since several winding machines are available on the market and since winding processes themselves differ considerably from one another (for example in regard to the type of filaments to be wound, their brightening etc.), it will be necessary in practice to carry out orienting tests.

In cases where cheeses are produced with considerable differences in traversing frequency and with considerable differences between the final radius and initial radius in the process according to the invention, it may be necessary, in order to obtain cheeses with a firm homogeneous structure, to keep the winding tension between the thread guide and the package substantially constant as a function of time. In the event of considerable differences in radius, it is advisable to apply an automatic adjustment whereas, in the case of relatively small differences in radius, it is sufficient for the winding tension between the traversing thread guide and the package to be readjusted by hand in stages.

An interfering function of relatively low frequency and/or amplitude is preferably superimposed upon the traversing frequency of the thread guide which is controlled or regulated in accordance with the invention. The interfering function may be kept constant throughout the duration of the winding process or may vary with time, the radius of the cheese or an equivalent parameter.

EXAMPLE 1 Polyamide 6 (final denier dtex 44 f 9) spun at 840 m/minute was wound into a cheese with the thread guide traversing at 260 double traversing strokes per minute.

The full cheeses weighed 6300 g. After standing for a certain period, the cheeses were drawn, the filaments being offwound from the cheeses at 750 m/minute. Two drawn cops each weighing 3100 g were to be produced from one cheese (6300 g). The yield (first and second drawn take-off together), of full drawn cops based on the number of possible full drawn cops, amounted to 55%.

If the number of filament breakages is plotted against the corresponding package diameter, it can clearly be seen that an increase in the number of filament breakages occurs at certain diameters of the cheeses (Figure 1).

Taking into account the increase in the diameter of the cheeses by about 3% both during winding and during the standing period, comparison of the filament breakage diameters observed with the mirror or constant pattern winding diameters calculated in accordance with formula (3) shows a distinct consistency.

Diameter of the cheeses k m k'=order of the mirror or constant Observed Calculated pattern winding.

21.2 21.6 2 10 1 22.8 22.8 3 14 3 23.5 23.7 2 9 2 24.4 24.4 3 13 3 26.5 26.5 2 8 1 29.0 28.9 3 11 3 30.4 30.4 2 7 2 31.8 31.9 3 10 3 35.4 35.4 2 6 EXAMPLE 2 Polyamide-6 (final denier dtex 44 f 10) spun at 800 m/minute was wound into cheeses with the filament guide member traversing at a constant rate of 320 double traversing strokes per minute.

The full cheese weighed 8500 g. After standing for a certain period, the cheeses were drawn, the offwinding speed of the filament from the cheeses amounting to 250 m/minute (a) and 800 m/minute (b). Three drawn cops each weighing 2800 g were to be produced from one cheese.

The yield (first, second and third drawing take-off together) of full drawn cops, based on the number of possible full drawn cops, amounted to 950/, in case (a) and to between 1.6 and 72% in case (b), depending upon the hardness of the package.

EXAMPLE 3 Polyamide-6 (final denier dtex 44 f 10) spun at 800 m/mintue was wound into cheeses with the thread guide traversing at a controlled rate.

The traversing of the thread guide was controlled as a function of time in accordance with the following formula:

Formula (1) is obtained from a. DH=a(r-r,)+DH, DH,-DH, b. a rE-rO

rO=initial radius of the cheese in cm final radius of the cheese in cm DHO=traversing frequency (min-') at the beginning of winding DHE=traversing frequency (min-') at the end of winding tE=duration of the winding process in minutes (hours) t=windingtime in minutes (hours).

Where rio=7.7 cm. ref=18.7 cm, Doh,=320 min-', Do;=506 min-', to=660, the following DH value is obtained for (1): DH=16.91 (26.4 t+59.29)"2+189.79 The full cheese weighed 8500 g. After standing for a certain period, the cheeses were drawn, the offwinding speed of the filament from the cheeses amounting to 800 m/minute.

Three drawn cops each weighing 2800 g were to be produced from one cheese.

The yield (first, second and third drawing take-off together) of full drawn cops, based on the number of possible full drawn cops, amounted to 94%.

WHAT WE CLAIM IS: 1. A winding process for producing cheeses from natural or synthetic, drawn or undrawn filaments, wherein the traversing frequency DH of the thread guide is controlled as a function of time, or a time dependant parameter in such a way that the absolute value of the change in n relative to the change in the radius r of the cheese (where n=f (r, DH) and is the ratio of the rotational frequency of the cheese to the traversing frequency of the filament guide member) is greater than the absolute value of the change in n as a function of the radius r of the cheese at a constant traversing frequency of the filament guide member and hence complies with the relation: dn when DH is variable > Idnl when DH is constant.

2. A winding process for producing cheeses as claimed in claim 1, wherein the winding process is controlled in accordance with the relation: d DH > O dr the coefficient of increase d DH dr being capable of assuming any values which are greater than zero and smaller than the maximum rate of increase in the traversing frequency of the particular winding machine.

3. A winding process for producing cheeses as claimed in claim 1 or 2, wherein the traversing frequencies are described by the expressions:

4. A process as claimed in any one of claims 1 to 3, wherein the winding tension is controlled or regulated during the winding process.

5. A process as claimed in any one of claims I to 4 wherein an interfering function of relatively low frequency and/or amplitude of the thread guide is superimposed upon the controlled traversing frequency of the filament guide member.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. spun at 800 m/mintue was wound into cheeses with the thread guide traversing at a controlled rate. The traversing of the thread guide was controlled as a function of time in accordance with the following formula: Formula (1) is obtained from a. DH=a(r-r,)+DH, DH,-DH, b. a rE-rO rO=initial radius of the cheese in cm final radius of the cheese in cm DHO=traversing frequency (min-') at the beginning of winding DHE=traversing frequency (min-') at the end of winding tE=duration of the winding process in minutes (hours) t=windingtime in minutes (hours). Where rio=7.7 cm. ref=18.7 cm, Doh,=320 min-', Do;=506 min-', to=660, the following DH value is obtained for (1): DH=16.91 (26.4 t+59.29)"2+189.79 The full cheese weighed 8500 g. After standing for a certain period, the cheeses were drawn, the offwinding speed of the filament from the cheeses amounting to 800 m/minute. Three drawn cops each weighing 2800 g were to be produced from one cheese. The yield (first, second and third drawing take-off together) of full drawn cops, based on the number of possible full drawn cops, amounted to 94%. WHAT WE CLAIM IS:

1. A winding process for producing cheeses from natural or synthetic, drawn or undrawn filaments, wherein the traversing frequency DH of the thread guide is controlled as a function of time, or a time dependant parameter in such a way that the absolute value of the change in n relative to the change in the radius r of the cheese (where n=f (r, DH) and is the ratio of the rotational frequency of the cheese to the traversing frequency of the filament guide member) is greater than the absolute value of the change in n as a function of the radius r of the cheese at a constant traversing frequency of the filament guide member and hence complies with the relation: dn when DH is variable > Idnl when DH is constant.

2. A winding process for producing cheeses as claimed in claim 1, wherein the winding process is controlled in accordance with the relation: d DH > O dr the coefficient of increase d DH dr being capable of assuming any values which are greater than zero and smaller than the maximum rate of increase in the traversing frequency of the particular winding machine.

3. A winding process for producing cheeses as claimed in claim 1 or 2, wherein the traversing frequencies are described by the expressions:

4. A process as claimed in any one of claims 1 to 3, wherein the winding tension is controlled or regulated during the winding process.

5. A process as claimed in any one of claims I to 4 wherein an interfering function of relatively low frequency and/or amplitude of the thread guide is superimposed upon the controlled traversing frequency of the filament guide member.

6. A process as claimed in claim 1, substantially as hereinbefore described with reference to any of the Examples and/or the accompanying drawings.

7. Cheeses when produced by a process as claimed in any one of claims 1 to 6.