EP0980928B1 - Method and device for sizing a fibre bundle - Google Patents

Description

The invention relates to a method and an apparatus for coating a Thread sheet with at least one size compartment for contacting the yarn of the sheet with sizing liquor and at least one sizing squeezer that separates from each other pressed rollers.

They are squeezers of very different types and tasks as well as for treatment known of various substrates, e.g. for tapes, webs or thread sheets, textiles or Paper as well as a calender.

GB-A 830 836 describes a method and a device for automatic control a continuous application of a certain amount of solid or liquid on a moving web, e.g. Paper, described. To regulate the material order, the The center distance between two rollers of a crushing unit is varied by a mechanical lifting gear.

In sizing devices, it is customary to treat the thread sheet to be treated with a sizing liquor to act, especially to dive in a trough and then in a Squeeze out excess sizing. Such a device is in DE 32 03 087 A1 described. Known are means for adjusting the contact pressure of the two rollers provided in their pinch joint. The contact pressure the rollers can be regulated depending on the amount of size that after squeezing remains on the thread sheet.

There are measuring devices, so-called order measuring devices, which allow the amount of measure the size remaining on a thread sheet after squeezing. With The squeeze pressure controller can be controlled from the measured values. Such measuring systems are specified in DE 42 34 279 A1.

The degree of sizing of a thread group can be dependent, among other things it can also depend on their pretreatment, for example on the original moisture be of the speed with which the size is applied and squeezed off it may continue to depend on the concentration of the applied Plain. If a certain amount of size is desired, the Order measuring devices mentioned, under certain circumstances in several places, e.g. before Finishing and after squeezing. The measurement results are used with the aim of the squeezing pressure, that is the specific surface pressure of the squeeze mechanism to be regulated so that the specified amount of size on the thread sheet remains.

Conventional devices for setting and regulating the squeeze pressure work with hydraulic or pneumatic cylinders. As a rule, one The roller of the crushing machine is firmly clamped, while the other roller is attached Hydraulic or pneumatic cylinders press against the first roller. The Setting the squeezing pressure and readjusting the pressure is therefore carried out by direct specification of pressure values. The corresponding cylinders can be opened simple way, for example by briefly opening or closing one Pressure fluid valve, control. In very compact systems, such as in DE 198 32 163 5 (98501), but becomes a major pneumatic disadvantage or hydraulic controls serious. Is immanent to these systems namely a more or less large hysteresis; that is the squeeze pressure of the roller pair in the pinch joint changes on different characteristic curves, depending on whether it rises or falls.

The cause of the aforementioned hysteresis phenomena are frictional resistances between piston and cylinder of the known pneumatic or hydraulic Institutions. In practice, there are also systems of this type that work smoothly with so-called bellows cylinders. These devices work with relatively large ones Volume of fluid (air or liquid) that is in the bellows during a pressure adjustment must be let in or pushed out of the bellows. Cause problems the bellows cylinder systems, especially in the event of a rapid change in speed, especially in the event of an emergency stop of the respective machine. As a rule, should then the pressure exerted by the squeeze mechanism almost instantaneously or in a few Seconds depending on the quality or viscosity of the respective sizing agent Dimension can be reduced. Such a sudden change in pressure can be not reach with conventional bellows cylinder systems, because the passage cross sections of the valves designed for controllability of the bellows cylinder pressure Do not allow instantaneous pressure loading. The through the use of the bellows cylinder The reduction in hysteresis is achieved by a limited reaction speed and thus a delayed pressure relief during emergency stops he buys.

The invention has for its object the accuracy of the setting of To improve the squeezing pressure and to make the control essentially hysterical, without limiting the speed of reaction.

The solution according to the invention for the above-mentioned method consists in that the contact pressure of the rollers directly by adjusting their center distance is controlled. Some improvements and further refinements of the invention are described in the subclaims.

The invention is based on the finding that the center distance of the Squeeze rollers change proportionally to the surface pressure and thus to the squeezing effect. This proportionality applies particularly to those moistened when squeezed or sized thread groups usual pressure ranges. Instead of a cylinder pressure specification (hydraulic or pneumatic) according to the invention is the mutual Distance between the roller axes - that is, a path directly. Surprisingly provides the immediate and therefore arbitrarily quick path setting a reproducible and hysteresis-free measured value proportional to the surface pressure of the crushing mechanism and thus to the squeezing effect.

According to the invention, the squeezing pressure is determined by directly specifying path values, namely the center distance, regulated. The respective path can be i.e. agents without delay, e.g. through a mechanical Hoist gear or a spindle gear but also by hydraulic or pneumatic Lifting elements, with increasing and falling pressure the same or exactly reproducible adjust so that the object underlying the invention in almost ideally is solved. If in the present context of freedom from hysteresis the squeeze pressure setting is spoken, it means that the Squeeze pressure specification within the desired accuracy is hysteresis-free.

It becomes a method for controlling the contact pressure of the rotatable axes Rolling a crushing machine described. To a hysteresis-free and in the case to achieve an almost instantaneous change in the contact pressure of an emergency stop, this is controlled directly by adjusting the center distance of the rollers. A major advantage of the invention in normal pressure controls is that From hysteresis. In addition, there is the advantage of a mechanical pressure command and thus the immediately following change in pinch pressure

Fig. 1

ein Diagramm betreffend den Zusammenhang von Achsabstand und Flächendruck,

Fig. 2a-c

drei Prinzip-Darstellungen eines Quetschwalzenpaars für verschiedene Achsabstände;

Fig. 3

eine Schlichtanlage; und

Fig. 4

ein Quetschwerk

Some details of the invention are explained on the basis of the schematic drawing of an exemplary embodiment. Show it:

Fig. 1

a diagram relating to the relationship between the center distance and surface pressure,

2a-c

three basic representations of a pair of squeeze rollers for different center distances;

Fig. 3

a finishing machine; and

Fig. 4

a squeeze mechanism

According to FIG. 1, the surface pressure f (N / cm ² ) is essentially proportional to the values of the center distance A between 90 and 100%. The center distance A = 100% corresponds to the geometrical distance between the two nip roll axes with rolls 1, 2 lying loosely adjacent to one another. The values 95% and 90% correspond to smaller center distances where rolls 1 and 2 do not line up as in FIG. 2a , but touch with a more or large nip width B on a nip strip 4 or 5 according to Fig. 2b or c.

The invention makes it possible for a symbolically represented in FIG Finishing plant 6 not only the crushing unit 7, but also the plant 6 as a whole extremely compact to build and sufficiently hysteresis-free or in the event of an emergency stop the machine to get the crusher setting almost instantaneously. The system according to the invention can squeeze the pressure, that is to say on the thread sheet 8 (general: the substrate) surface pressure, faster than speed proportional change and when comparing target and actual values the the amount of liquor 10 applied to the thread sheet 8, for example in the trough 9, is constant to regulate.

4, the center distance 11 of the two rollers 1, 2 with the aid of threaded spindles 12, which act between the axes 13, 14 of the rollers 1, 2, set exactly become. The setting can be set to predetermined target values, for example in Dependence on the actual sizing recorded with the help of an order measuring device 15 (FIG. 2) respectively.

LIST OF REFERENCE NUMBERS

1 =

roller

2 =

roller

3 =

line

4 =

Nipp Strip

5 =

Nipp Strip

6 =

sizing machine

7 =

squeezer

8 =

yarn sheet

9 =

trough

10 =

sizing liquor

11 =

Wheelbase

12 =

screw

13 =

Axis 1)

14 =

Axle (2)

15 =

Auftragsmeßgerat

Claims (4)

1. Method for sizing a fibre bundle (8) with at least one sizing compartment for contacting the yarn of the bundle with sizing liquor (10) and at least one sizing mangle (7) comprising rollers (1, 2) pressed against one another, characterised in that the contact pressure of the rollers (1, 2) is controlled directly by adjusting their axial spacing (11).
2. Method according to claim 1, characterised in that the axial spacing (11) is measured by path sensors or by increments of the rotational movement of a lifting spindle (12) or the like.
3. Device for carrying out a method for sizing a fibre bundle according to either of claims 1 or 2, with at least one sizing compartment for contacting the yarn of the bundle with sizing liquor (10) and at least one sizing mangle (7) comprising rollers (1, 2) pressed against one another, characterised in that a mechanical lifting gearing is provided for adjusting the axial spacing (11) of the rollers (1, 2).
4. Device according to claim 3, characterised in that at least one threaded spindle (12) is provided for adjusting the axial spacing (11).

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