EP0470577B1 - Dosing method and apparatus for the delivery of predeterminate quantities of fiber flocks per unit of time - Google Patents

Description

The present invention relates to a metering method and a metering device for delivering predeterminable quantities of fiber flakes per unit of time by means of two feeding devices arranged at the lower end of a flake shaft and forming a conveying gap between them.

A method or a device of this type is known, for example, from British patent specification 735 172 or the corresponding Swiss patent specification 313 355. A similar method or a similar device is also known from DE-OS 37 13 590, wherein an opening roller is additionally arranged below the feed rollers forming the feed devices.

Further examples can also be found in German patent 196 821, German patent 31 51 063 and Japanese document 62-263327.

In the production of yarn, mixtures of different fiber-like components, that is to say fibers of different origins, types, qualities, colors or other characteristics, are usually mixed in order to produce fiber mixtures which are subsequently carded and fed to the further spinning processes.

The mixing can be carried out, for example, in such a way that the different types of fibers are filled into respective filling shafts and are deposited on a conveyor belt running below the shafts by means of the feed rollers arranged at the lower end of the flake shafts. This creates a continuous layered structure on the conveyor element, which is then fed to an opening roller, this opening roller loosening individual flakes from the layered structure and ensuring good mixing of the different fibers of the different layers. By controlling the speed of rotation of the individual feed rollers it is possible to determine the desired proportions of the individual fiber components.

Efforts are made to control the fill level of the fiber flakes in the individual shafts in such a way that this fill level remains approximately constant, so that the desired fiber quantities are metered onto the rotating conveyor belt at a constant fill level and a predetermined speed of rotation of the feed rollers.

With this known dosing method or this known dosing device, it is only possible to a limited extent to achieve the respectively prescribed dosing quantities. The previously known devices only take into account relatively imprecise fluctuations in the density, the filling height and the degree of opening of the fiber flakes.

Because of this inaccuracy, weighing dishes have also been proposed, with the individual components being weighed prior to mixing. However, these devices are relatively expensive.

It is therefore the task of developing a method or a device of the type mentioned at the outset in such a way that a high dosing accuracy can be achieved with inexpensive manufacture, without the fill level in the flake shaft having to be precisely predetermined.

European patent application EP-A-0 383 246 of the present applicant, published on August 22, 1990, provides a metering method in which the feed devices are formed by feed rollers which can be rotated in opposite directions, with the further characteristics that at least one of the feed rollers is directed in the direction of the other Feed roller pretensioned and movable away from it under the flake pressure is that the distance between the two feed rollers or a value proportional to this is measured and that the speed of at least one of the feed rollers is controlled so that the product (n · x) of the speed (n) and the distance (x) at least on average remains constant. In terms of the device, this European application 90 102 745.8 published on August 22, 90 provides that the axis of rotation of one feed roller is mounted displaceably towards and away from the other feed roller in the direction of the axis of rotation of the other feed roller and is biased in the direction of the axis of rotation of the other feed roller so that one Distance measuring device is provided which determines the distance between the two feed rollers or a value proportional to this during operation of the flake conveying and that a control is provided which regulates the speed of the feed rollers based on the determined distance in the sense of reaching a predetermined target value of the current production .

This document EP-A-0 383 246 falls under Article 54 (3) EPC and is of no importance for the question of inventive step.

The object of the present invention is to propose alternative solutions to the above object.

Accordingly, a method according to claim 1 and an apparatus according to claim 4 are provided according to the present invention.

• a. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Rutsche, oder
• b. einer angetriebenen drehbaren Speisewalze und einem dieser gegenüberliegenden angetriebenen oder frei umlaufenden Band, oder
• c. zwei einander gegenüberliegenden umlaufenden Bändern, wobei wenigstens eines der Bänder angetrieben wird und das andere entweder umläuft oder ebenfalls angetrieben wird, oder
• d. einem angetriebenen umlaufenden Band und einer ihm gegenüberliegenden Rutsche, oder
• e. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden frei drehbar angeordneten weiteren Speisewalze, oder
• f. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Speisemulde,

wobei bei allen möglichen Ausführungen a. bis f. der Förderspalt zu einer minimalen Breite hin konvergiert und wenigstens eine der Speiseeinrichtungen in Richtung der anderen Speiseeinrichtung hin vorgespannt wird und von dieser unter dem Flockendruck wegbewegbar ist, derart, daß der Abstand zwischen den beiden Speiseeinrichtungen im Sinne einer Veränderung der minimalen Breite des Förderspaltes geändert wird, daß die minimale Breite des Förderspaltes oder ein ihr proportionaler Wert ermittelt wird und daß die Oberflächenlaufgeschwindigkeit der angetriebenen Speiseeinrichtung oder Speiseeinrichtungen so geregelt wird, daß zumindest der Mittelwert des Produktes dieser Breite und der Oberflächenlaufgeschwindigkeit konstant bleibt.The present invention is therefore based on the knowledge that the above-mentioned object can be achieved not only by means of two feed rollers, but also if the feed devices consist of either

• a. a driven rotatable feed roller and a slide opposite this, or
• b. a driven rotatable feed roller and a driven or freely circulating belt opposite it, or
• c. two opposing rotating belts, at least one of the belts being driven and the other either rotating or also being driven, or
• d. a driven circulating belt and a slide opposite it, or
• e. a driven rotatable feed roller and a further feed roller arranged opposite to it and freely rotatable, or
• f. a driven rotatable feed roller and a feed trough opposite this,

with all possible designs a. to f. the conveyor gap converges to a minimum width and at least one of the feed devices is biased in the direction of the other feed device and can be moved away from it under the flake pressure, such that the distance between the two feed devices is changed in the sense of a change in the minimum width of the conveyor gap that the minimum width of the conveyor gap or a value proportional to it is determined and that the surface running speed of the driven feed device or feed devices is controlled so that at least the mean value of the product of this width and the surface running speed remains constant.

• a. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Rutsche, oder
• b. einer angetriebenen drehbaren Speisewalze und einem dieser gegenüberliegenden angetriebenen oder frei umlaufenden Band, oder
• c. zwei einander gegenüberliegenden umlaufenden Bändern, wobei wenigstens eines der Bänder angetrieben wird und das andere entweder umläuft oder ebenfalls angetrieben wird, oder
• d. einem angetriebenen umlaufenden Band und einer ihm gegenüberliegenden Rutsche, oder
• e. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden frei angetriebenen drehbar angeordneten weiteren Speisewalze, oder
• f. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Speisemulde,

wobei bei allen möglichen Ausführungsformen a. bis f. der Förderspalt zu einer minimalen Breite hin konvergiert, daß eine Vorspanneinrichtung vorgesehen ist, welche wenigstens eine der Speiseeinrichtungen in Richtung der anderen Speiseeinrichtung hin vorspannt, wobei wenigstens eine der Speiseeinrichtungen von der jeweils anderen Speiseeinrichtung unter dem Flockendruck wegbewegbar angeordnet ist, daß eine Wegmeßeinrichtung vorgesehen ist, welche den sich im Betrieb der Flockenförderung ergebenden Abstand zwischen den beiden Speiseeinrichtungen an der Stelle der minimalen Breite bzw. einen diesem proportionalen Wert ermittelt, und daß eine Regelung vorgesehen ist, welche die Oberflächenlaufgeschwindigkeit der beweglichen Speiseeinrichtung(en) aufgrund des ermittelten Abstandesim Sinne des Erreichens eines vorgegebenen Sollwertes der Momentanproduktion regelt.In terms of device, this solution consists in that the feeding devices consist of either

• a. a driven rotatable feed roller and a slide opposite this, or
• b. a driven rotatable feed roller and a driven or freely circulating belt opposite it, or
• c. two opposing rotating belts, at least one of the belts being driven and the other either rotating or also being driven, or
• d. a driven circulating belt and a slide opposite it, or
• e. a driven rotatable feed roller and an opposing freely driven rotatably arranged further feed roller, or
• f. a driven rotatable feed roller and a feed trough opposite this,

where in all possible embodiments a. to f. the conveying gap converges to a minimum width that a pretensioning device is provided, which pretensions at least one of the feeding devices in the direction of the other feeding device, wherein at least one of the feeding devices is arranged so as to be movable away from the other feeding device under the floc pressure, so that a displacement measuring device is provided which determines the distance between the two feeding devices at the location of the minimum width or a value proportional to this during the operation of the flake conveying, and that a regulation is provided which determines the surface running speed of the movable feeding device (s) on the basis of the determined distance in the sense of Reaching a predetermined setpoint of the current production regulates.

Further developments of this method or device according to the invention are specified in subclaims 2 to 3 and 5 to 9.

auch bei anderen Speiseeinrichtungen ihre Gültigkeit beibehält, obwohl die Konstante K einen anderen Wert annimmt und man anstelle der Drehzahl (n) dem Speisewalze die Oberflächengeschwindigkeit (u) der angetriebenen Speiseeinrichtung(en) einsetzen muß.This is because the inventors have recognized that the equation given in the application EP-A-0 383 246 published on August 22, 1990

also remains valid for other feed devices, although the constant K assumes a different value and the surface speed (u) of the driven feed device (s) must be used instead of the speed (n) of the feed roller.

• a. zwei einander gegenüberliegenden angetriebenen drehbaren Speisewalzen, oder
• b. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Rutsche, oder
• c. einer angetriebenen drehbaren Speisewalze und einem dieser gegenüberliegenden angetriebenen oder frei umlaufenden Band, oder
• d. zwei einander gegenüberliegenden umlaufenden Bändern, wobei wenigstens eines der Bänder angetrieben wird und das andere entweder umläuft oder ebenfalls angetrieben wird, oder
• e. einem angetriebenen umlaufenden Band und einer ihm gegenüberliegenden Rutsche, oder
• f. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden frei drehbar angeordneten weiteren Speisewalze, oder
• g. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Speisemulde,

wobei die Relativlage der beiden Speiseeinrichtungen einander gegenüber bei gleichzeitiger Messung der die beiden Speiseeinrichtungen auseinanderdrückenden Kraft (P) oder eines dieser proportionalen Wertes zumindest im wesentlichen konstant gehalten wird, wobei die Oberflächenlaufgeschwindigkeit (u) der angetriebenen Speiseeinrichtung(en) unter Berücksichtigung der sich ändernden Kraft so geregelt wird, daß zumindest der Mittelwert des Produktes (u · p) der Oberflächenlaufgeschwindigkeit und der Kraft konstant bleibt.In further development of this concept there is an alternative solution to the above-mentioned object procedurally according to claim 10, that the dining facilities consist of either

• a. two opposite driven rotatable feed rollers, or
• b. a driven rotatable feed roller and a slide opposite this, or
• c. a driven rotatable feed roller and a driven or freely circulating belt opposite it, or
• d. two opposing rotating belts, at least one of the belts being driven and the other either rotating or also being driven, or
• e. a driven circulating belt and a slide opposite it, or
• f. a driven rotatable feed roller and a further feed roller arranged opposite to it and freely rotatable, or
• G. a driven rotatable feed roller and a feed trough opposite this,

the relative position of the two feed devices relative to one another being kept at least substantially constant while simultaneously measuring the force (P) pushing the two feed devices apart or a value proportional thereto, the surface running speed (u) of the driven feed device (s) taking into account the changing force is regulated so that at least the mean value of the product (u · p) of the surface running speed and the force remains constant.

• a. zwei einander gegenüberliegenden angetriebenen drehbaren Speisewalzen, oder
• b. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Rutsche, oder
• c. einer angetriebenen drehbaren Speisewalze und einem dieser gegenüberliegenden angetriebenen oder frei umlaufenden Band, oder
• d. zwei einander gegenüberliegenden umlaufenden Bändern, wobei wenigstens eines der Bänder angetrieben wird und das andere entweder umläuft oder ebenfalls angetrieben wird, oder
• e. einem angetriebenen umlaufenden Band und einer ihm gegenüberliegenden Rutsche, oder
• f. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden frei drehbar angeordneten weiteren Speisewalze, oder
• g. einer angetriebenen drehbaren Speisewalze und einer dieser gegenüberliegenden Speisemulde,

wobei bei allen möglichen Ausführungsformen a. bis g. der Förderspalt zu einer minimalen Breite hin konvergiert, daß nur für eine gewählte Produktion (ṁ_soll) die Relativlagen der beiden Speiseeinrichtungen einander gegenüber zumindest im wesentlichen konstant bleiben, daß eine Kraftmeßeinrichtung vorgesehen ist, um die Kraft (P) zu messen, welche versucht, die beiden Speiseeinrichtungen auseinanderzudrücken, und daß eine Regelung vorgesehen ist, welche die Oberflächenlaufgeschwindigkeit (u) der angetriebenen Speiseeinrichtung(en) aufgrund der ermittelten Kraft im Sinne des Erreichens des vorgegebenen Sollwertes (ṁ_soll) der Momentanproduktion (ṁ) regelt.In terms of the device according to claim 11, this solution consists in that the feeding devices consist of either

• a. two opposite driven rotatable feed rollers, or
• b. a driven rotatable feed roller and a slide opposite this, or
• c. a driven rotatable feed roller and a driven or freely circulating belt opposite it, or
• d. two opposing belts, wherein at least one of the belts is driven and the other either rotates or is also driven, or
• e. a driven circulating belt and a slide opposite it, or
• f. a driven rotatable feed roller and a further feed roller arranged opposite to it and freely rotatable, or
• G. a driven rotatable feed roller and a feed trough opposite this,

where in all possible embodiments a. to g. the conveying gap converges to a minimum width, that only for a selected production (ṁ _should ) the relative positions of the two feed devices remain at least substantially constant relative to one another, that a force measuring device is provided to measure the force (P), which tries to force apart the two feed means, and that a control is provided which of the driven feed device (s) based on the detected force in the sense of reaching the predefined set value (ṁ _set), the surface speed (u) of the momentary production (ṁ) controls.

wo die Oberflächenlaufgeschwindigkeit der angetriebenen Speiseeinrichtung (n) und (P) die oben erwähnte Kraft ist. Auch hier ist K eine Konstante, die aber eine andere Größe haben wird als bei der Gleichung 1 und bei der entsprechenden Gleichung der am 22.08.90 veröffentlichten europäischen Anmeldung 90 102 745.8.In the derivation of equation 1 given in European application 90 102 745.8, the relationship with the density of the product in the conveying gap has been worked out, and the inventors have now recognized that an equation of the same form as equation 1 also results, if you keep the working distance between the two feeding devices constant and instead of changing this distance the changing one Measures force on the dining facilities. This force is in fact proportional to the density of the flock flow flowing through the delivery gap. You then get an equation of the form

where the surface running speed of the driven feeder (s) and (P) is the force mentioned above. Here, too, K is a constant, but it will have a different size than in Equation 1 and in the corresponding equation of the European application 90 102 745.8 published on August 22, 1990.

In order to illustrate the present invention more clearly, the description of the figures in FIGS. 1 to 8 of the above-mentioned European application 90 102 745.8 is reproduced again first, and then embodiments 9 to 16 according to the present invention are explained with reference to the further FIGS.

Figur 1

eine schematische Seitenansicht einer Mischanlage, welche mit drei bekannten Dosiervorrichtungen ausgestattet ist,

Figur 2

eine perspektivische Darstellung der zwei Speisewalzen und der Öffnerwalze einer bekannten Dosiervorrichtung,

Figur 3

eine graphische Darstellung zur Erläuterung des bekannten Regelverfahrens,

Figur 4

eine Seitenansicht einer ersten detaillierten Ausführungsform einer bekannten Dosiervorrichtung,

Figur 5

eine Seitenansicht einer weiteren bekannten Dosiervorrichtung,

Figuren 6, 7 und 8

schematische Darstellungen von verschiedenen bekannten Ausführungsvarianten der Vorspanneinrichtung,

Figur 9

eine Seitenansicht einer erfindungsgemäß abgewandelten Ausführung der Vorrichtung der Figur 2,

Figur 10

eine Seitenansicht entsprechend der Figur 9, jedoch von einer weiteren Ausführungsform, bei der die eine Speisewalze durch eine Rutsche ersetzt worden ist,

Figur 11

eine Seitenansicht entsprechend der Figur 9, jedoch von einer weiteren Ausführungsform, bei der die eine Speisewalze durch ein umlaufendes Band ersetzt worden ist,

Figur 12

eine Seitenansicht entsprechend der Figur 9, jedoch von einer weiteren Ausführungsform, bei der die eine Speisewalze durch eine Speisemulde ersetzt worden ist,

Figur 13

eine Seitenansicht noch einer erfindungsgemäß Ausführungsform ähnlich der Figur 2, jedoch bei Verwendung zweier umlaufender angetriebener Bänder,

Figur 14

eine Seitenansicht entsprechend der Figur 13, jedoch in einer abgewandelten Ausführung, bei der eines der beiden umlaufenden Bänder durch eine Rutsche ersetzt worden ist,

Figur 15

eine Seitenansicht einer abgewandelten Ausführung der Vorrichtung gemäß Figur 12, und

Figur 16

eine Seitenansicht einer Ausführung ähnlich der Figur 9, bei der aber die beiden Speisewalzen einen konstanten Abstand voneinander aufweisen.

The figures show:

Figure 1

2 shows a schematic side view of a mixing plant which is equipped with three known metering devices,

Figure 2

2 shows a perspective illustration of the two feed rollers and the opening roller of a known metering device,

Figure 3

a graphical representation to explain the known control method,

Figure 4

2 shows a side view of a first detailed embodiment of a known metering device,

Figure 5

a side view of another known metering device,

Figures 6, 7 and 8

schematic representations of various known design variants of the pretensioning device,

Figure 9

2 shows a side view of an embodiment of the device of FIG. 2 modified according to the invention,

Figure 10

9 shows a side view corresponding to FIG. 9, but of a further embodiment in which the one feed roller has been replaced by a slide,

Figure 11

9 shows a side view corresponding to FIG. 9, but of a further embodiment in which the one feed roller has been replaced by a circulating belt,

Figure 12

9 shows a side view corresponding to FIG. 9, but of a further embodiment in which the one feed roller has been replaced by a feed trough,

Figure 13

3 shows a side view of another embodiment according to the invention similar to FIG. 2, but when using two rotating driven belts,

Figure 14

13 shows a side view corresponding to FIG. 13, but in a modified version in which one of the two circulating belts has been replaced by a slide,

Figure 15

a side view of a modified embodiment of the device according to Figure 12, and

Figure 16

a side view of an embodiment similar to Figure 9, but in which the two feed rollers are at a constant distance from each other.

In all embodiments, the same parts are identified with the same reference numerals, but with a decimal point if there are deviations from the parts already described.

1 consists of a rotating conveyor belt 10 and three identically designed metering devices 12, which are arranged in a row above the conveyor belt 10. As will be explained in more detail below, each metering device 12 consists of a filling shaft 14 with a shop window 16 and two to three feed rollers 18, 20 arranged at the lower end of the shaft and an opening roller 22. The flakes present in the shaft, the upper limit of which is 24, are detected by the feed rollers 18 and 20 rotating in the respective directions 26, 28 and fed to the opening roller 22 through the conveying gap formed between these two rollers. The latter rotates faster than the feed rollers and loosens flakes from the supplied flake cotton wool and feeds them through a channel 30 in the form of open, loose flakes 32 onto the upper run 34 of the conveyor belt.

The loose flake bundles 32.1 and 32.2 from the two further metering devices are placed in layers on the first layer formed by the flake bundle 32 and guided with the upper run of the conveyor belt 34 in the direction of arrow 36 to the right end of the mixing device in FIG. Here is a further rotating conveyor belt 38, which rotates in the direction of arrow 40 and whose lower run 42 is inclined towards the upper run 34 of the conveyor belt 10 in the conveying direction 36. The three layers 32, 32.1 and 32.2 are thus compressed and then captured in the feed nip of two feed rollers 44, 46. The feed rollers 44, 46 feed the layered structure thus formed to an opening roller 48 which rotates in the direction of the arrow 50 and loosens the flakes from the layered structure and transfers them to the subsequent processing via a shaft 52. Any dirt or waste released by the opening by means of the opening roller 48 is collected in the outlet chamber 54 and optionally removed from here by means of an air stream.

It goes without saying that the embodiment shown in FIG. 1 is not limited to three metering devices 12, but any number of layers can be arranged above the conveyor belt 10.

The practical design of the feed rollers 18, 20 and the opening roller 22 can be seen somewhat more clearly in FIG. 2.

The two side walls 56, 58 of the flake shaft extend close to the surfaces of the feed rollers 18 and 20 and diverge slightly from each other so that no flake jams occur. The flakes 60 in the shaft 12, which have a high degree of opening, are fed by the feed rollers 18 rotating in opposite directions in the direction of the arrow 26, 28 or 20 detected and compressed to a flake cotton wool 62. The opening roller 22 then loosens the flakes out of this flake cotton wool and forms a flake flow 32 which continues in the direction of arrow 64 in the direction of the conveyor belt. All flakes detected by the feed rollers rotating at the speed n are transported through a conveyor gap, the width x of which represents the smallest distance between the two feed rollers and the length of which corresponds to the length of the feed rollers or the width of the side walls of the shaft.

The axis of rotation of the feed roller 18 is identified by 66, the axis of rotation of the feed roller 20 by 68 and the axis of rotation of the opening roller 22 by 70. The axis of rotation 66 of the feed roller 18, like the axis of rotation 70 of the opening roller 22, is fixedly arranged in the flake shaft. However, the axis of rotation 68 of the feed roller 20 is carried by two arms 72, of which only one can be seen in FIG. 2. The second arm 72 is located on the other end of the feed roller 20 and is designed in exactly the same way as the arm 72 shown. This arm 72 is mounted on the axis of rotation of the opening roller 22 and can therefore carry out rotary movements about this axis of rotation 70 in the direction of the double arrow 74. As can be seen, such movements lead to a change in the distance x.

A prestressing device 76 is provided on the right-hand side of FIG. 2, in the form of a prestressing spring 78, which rests at one end against a stop 80 fixedly arranged on the filling shaft and at its other end against a stop 82 connected to the arm 72. A rod 84 extends between the stop 80 and the stop 82 and is arranged displaceably within the stop 82. It is understood that a second pretensioning device 76 is provided on the other end of the feed roller 20 and there also on the associated arm 72 presses. The two springs 78 therefore try to reduce the distance x. The minimum distance x is predetermined by a stop device 86 which cooperates with the arm 72 shown. Another stop device 86 is located on the other end of the feed roller 20 and works in a corresponding manner with the arm 72 there.

The distance x arises in operation depending on the pressure prevailing in the conveyor shaft, the density and the degree of opening of the flakes and the force of the springs 78, the size of the distance x being able to be determined by the displacement movement of the rod 84 within the stop 82. The rod 84 and the stop 82 are designed as a path measuring device.

The dosing method according to the invention and the control carried out are also explained below with reference to FIG. 3.

m

= Masse;

t

= Zeit;

ṁ

= Massenstrom = Relativproduktion einer Dosiervorrichtung = Masse/Zeit;

v̇

= Volumenstrom = Volumen/Zeit;

ρ

= Materialdichte;

n

= Drehzahl der Speisewalzen;

u

= Umfangsgeschwindigkeit der Speisewalzen;

d

= Durchmesser der Speisewalzen;

l

= Länge der Speisewalzen;

x

= variable Öffnungsweite des Förderspaltes;

A

= Öffnungsquerschnitt des Förderspaltes = l · x;

s

= Transportlänge.

First the following definitions are introduced:

m

= Mass;

t

= Time;

ṁ

= Mass flow = relative production of a dosing device = mass / time;

v̇

= Volume flow = volume / time;

ρ

= Material density;

n

= Speed of the feed rollers;

u

= Peripheral speed of the feed rollers;

d

= Diameter of the feed rollers;

l

= Length of feed rollers;

x

= variable opening width of the conveyor gap;

A

= Opening cross section of the conveyor gap = l · x;

s

= Transport length.

The mass flow equal to the current production ṁ is v̇ · ρ.

Nun ist ρ hier die Materialdichte im Förderspalt und diese ist aufgrund der Vorspannung mit im wesentlichen konstanter Kraft zumindest im wesentlichen konstant. Nachdem d, π und l auch konstant sind können wir schreiben:

$\text{ρ · d · π · l = K ;}$

Weiterhin ist:

$$\dot{\text{m}}\text{=}\frac{\text{dm}}{\text{dt}}\text{= K · n · x ;}$$

d.h. $\text{dm = K · n · x · dt}$

, woraus wir errechnen können

wobei wir die Momentanproduktion über ein Intervall t₂-t₁ so schreiben können

wobei erfindungsgemäß für t₂-t₁ vorzugsweise ein konstantes Intervall gewählt wird.Taking into account the definitions given above, the following equation can also be created:

Now ρ here is the material density in the conveyor gap and this is at least essentially constant due to the prestressing with an essentially constant force. After d, π and l are also constant we can write:

$\text{ρ · d · π · l = K;}$

Furthermore:

$$\dot{\text{m}}\text{=}\frac{\text{dm}}{\text{German}}\text{= K · n · x;}$$

ie $\text{dm = K · n · x · dt}$

from which we can calculate

where we can write the current production over an interval t₂-t₁

whereby according to the invention preferably a constant interval is chosen for t₂-t₁.

Based on the graphic representation of Figure 3 you can see that the mass m actually corresponds to the area below the curve in the time interval t₂-t₁. m therefore represents the averaged value in this time interval.

The regulation of the speed of the feed rollers is now carried out as follows:
First, the opening cross-section is detected and integrated at a constant speed n 1 over the measurement over the fixed time interval t 2-t 1, from which the instantaneous production ṁ 1 results.

This value is compared _to now m 'with the target production and control of the speed made so that a new speed gives n₂ that remains constant for the next time interval.

This process is repeated for time interval time interval, the control _should be ṁ quickly to the desired average output value is established. The calculations themselves can be carried out by a microprocessor to which the constant parameters are known and to which the current measurement results of the path measuring device 82 and the speed of the feed rollers 18 and 20 are given. The drive of the various rollers can be seen more clearly from FIG. 4, the roller arrangement being somewhat modified compared to the arrangement in FIG.

FIG. 4 shows a metering device which corresponds approximately to metering device 12 at the left end of FIG. 1. Here, however, a further roller 88 is provided, which feeds the flakes in the shaft to the feed rollers 18 and 20.

In this example, the roller 18 is designed to be displaceable, the roller 20, however, remains standing. The axis of rotation 66.1 of the displaceable feed roller 18.1 is here also supported by two arms 72.1, which in this example are not supported by the axis of rotation of the opening roller 22 but by the axis of rotation 90 of the additional roller 88. The pretensioning device 76.1 is now arranged on the left side of the flake shaft and, as in the embodiment according to FIG. 2, engages the arm 72.1. For the sake of simplicity, neither the spring nor the displacement measuring device is shown here, but it goes without saying that these units are present in exactly the same manner as in the embodiment according to FIG is provided.

The feed rollers 18.1 and 20.1 and the further roller 88 are driven by a common motor 92. The drive consists of a chain 94 which is driven by a sprocket 96 on the output shaft of the motor 92. The chain 94 rotates with a tensioning device 104 on a sprocket 98 provided on the one end face of the roller 88 and on another sprocket 100 provided on the one end face of the roller 20.1 and on a sprocket 102 provided for tensioning the chain. The direction of rotation of the chain is indicated by arrow 106, from which the desired direction of rotation 28 of the feed roller 20.1 and the direction of rotation 108 of the further roller 88 result. The feed roller 18.1 is driven by a further rotating chain 110 which is driven by the chain wheel 98 designed as a double chain wheel. The sprockets 100 and 98 and the sprocket 112 on one end of the feed roller 18.1 have the same diameter, as a result of which the rotational speeds of these rollers are all the same.

The opening roller 22.1 is driven by a separate motor 114 and a rotating chain 116.

FIG. 4 also shows how the opening roller rotates within sheet metal guides 118 and 120, the sheet metal guide 120 being adjustable in the direction of the double arrow 122. The sheet 120 forms, together with another sheet 124, a guide channel 126 for the flake nonwoven. The special shape of this guide channel 126 slows the flakes after they emerge from the area of the opening roller and gently guides them to the conveyor belt 34 without producing a pronounced air flow which could possibly interfere with the formation of sandwiches on the conveyor belt.

The reference numeral 128 represents the feed channel by means of which the flakes are pneumatically transported into the shaft 14.1.

Finally, 130 represents the computer, which controls the speed of the feed rollers via line 132 and receives the signal of the path measuring device installed in the pretensioning device 76.1 via line 134.

FIG. 5 shows a further embodiment, the arrangement of the feed rollers 18, 20 and the opening roller 22 being designed in accordance with the arrangement according to FIG. 2, for which reason these parts are not described in detail. However, it should be pointed out that the motor 92.1 drives the feed roller 18.2 via the rotating chain 136. This chain is tensioned by the tensioning device 104.1 and the tensioning wheel 102.1. There are three sprockets on the axis of rotation of the opening roller, one sprocket being connected to the opening roller in a rotationally fixed manner. The other two are freely rotatable about their axis of rotation, but are coupled together. Of these two coupled sprockets, one is driven by the revolving chain 136, the other drives by another revolving chain Chain 138 on the feed roller 20.

The second motor 114.1 drives an intermediate wheel 142 via the chain 140, which, via a further sprocket 144 coupled to it, a rotating chain 146, a further double sprocket 148 and a further rotating chain 150, which the opening roller 22 via the sprocket rotatably coupled to it drives.

Above the shaft 14.2 there is a further metering device, the task of which is to keep the filling height of the flakes within the shaft 14.2 within predetermined limits. For this purpose, flakes from a buffer space 154 are fed to the further metering device 152, namely from four feed rollers 156, 158, 160 and 162. These feed rollers 156, 158, 160, 162 are driven by their own motor 164, specifically via a rotating one Chain 166. The respective directions of rotation of the feed rollers 156, 158, 160, 162 can be seen from the arrows shown in each case. To maintain these directions of rotation, it is necessary to drive the feed roller 160 through the feed roller 162 via a separate chain 168. From this it can be seen that the circulating chain 166 on the feed roller 160 is guided only via a freely rotatable sprocket.

As already explained, the metering device 152 is almost identical in construction to the metering device at the lower end of the filling shaft 14.2. The two feed rollers 170, 172 are driven by the motor 174, specifically via a revolving chain 176, which is essentially guided like the chain 136 at the lower end of the conveyor shaft, which is why the exact arrangement is not described in detail. Here, too, the second feed roller 172 is driven by a separate rotating chain 78.

The opening roller 180 is driven by the sprocket 142 via a further rotating chain 182, from which it can be seen that the sprocket 142 is designed as a double sprocket.

The metering device 152 is switched on and off via light barriers 184, 186 which determine the upper and lower limits of the filling height. Since the shaft 14.2 is relatively wide, measured in the direction perpendicular to the plane of the drawing, two light barriers are provided on both sides in order to take into account the inclined positions of the upper limit of the flake filling. The metering device 152 can be switched on when both lower light barriers 184 are free, but can be switched off when both upper light barriers 186 are interrupted.

However, depending on the number of light barriers covered by the metering device, different mass flows can also be assigned. The bottom light barrier can be an idle protection, the top one an overflow protection.

FIG. 6 shows a schematic illustration of a pretensioning device 76.2 for the one feed roller 20, this pretensioning device being very similar to the pretensioning device 76 of FIG. In the embodiment according to FIG. 6, however, the ingenious geometry of the arrangement and the use of the feed roller 20 as a balance weight and by the provision of an additional balance weight 200 ensure that in all positions of the feed roller 20 within the intended swiveling range a an at least essentially constant clamping force is exerted on the flake mass 62 between the two feed rollers 18, 20.

It is clear that at the maximum opening angle α, that is to say when the arm 72 is in a position in which its longitudinal direction 204 is in the position 206, the spring 84 is compressed more than in the position shown, that is to say that exerted by the spring Elasticity represents a maximum. On the other hand, the feed roller 20 causes a greater compression force on the spring 84 at the maximum angle α, since the feed roller 20 then has a larger lever arm for the weight force directed vertically downwards. The additional balance weight 200, which exerts a counterclockwise torque on the arm 72 via the arm 202, in turn generates an additional force in the direction of the spring force 84 on the fiber flakes, which are located between the two feed rollers 18 and 20. This additional force has a relatively small value in the angular position 206. Thus, the tensioning force exerted on the flakes located between the two feed rollers 18 and 20 is a value in position 206 which corresponds approximately to the difference between the maximum spring force and the maximum value of the weight force of the feed roller 20 directed against this spring force.

, so erreicht die Kraft der Feder 84 lediglich ihren minimalen Wert, und es wird keine ausgeprägte Gegenkraft durch das Gewicht der Speisewalze 20 auf die Feder 84 ausgeübt. Dagegen übt das Zusatzgewicht 200 aufgrund der nunmehr maximalen Länge des Hebelarms für senkrecht nach unten gerichtete Kräfte ein maximales Drehmoment auf den Arm 72 aus, welches die von der Feder 84 ausgeübte Kraft unterstützt. Somit setzt sich die auf die Flocken zwischen den beiden Speisewalzen 18 und 20 ausgeübte Kraft im wesentlichen aus dem Unterschied zwischen der nunmehr reduzierten Federkraft 84 und der ebenfalls reduzierten Gewichtskraft der Speisewalze 20 plus der zugleich erhöhten Gewichtskraft des Zusatzgewichtes 200 zusammen, und man kann durch ausgeklügelte Auswahl der Geometrie sowie der einzelnen Gewichte und der Federkraft bzw. der Federkonstante erreichen, daß die auf die Flocken ausgeübten Kräfte zwischen den beiden Speisewalzen 18 und 20 über den gesamten Winkelbereich α zumindest im wesentlichen konstant bleiben.In contrast, the arm 72 has reached the smallest angular position 208, that is $\text{α = 0}$

, the force of the spring 84 only reaches its minimum value, and no pronounced counterforce is exerted on the spring 84 by the weight of the feed roller 20. On the other hand, due to the now maximum length of the lever arm for vertically downward forces, the additional weight 200 exerts a maximum torque on the arm 72, which supports the force exerted by the spring 84. Thus, the force exerted on the flakes between the two feed rollers 18 and 20 is essentially composed of the difference between the now reduced spring force 84 and the likewise reduced weight of the feed roller 20 plus the increased weight of the additional weight 200, and one can achieve by sophisticated selection of the geometry and the individual weights and the spring force or the spring constant that the forces exerted on the flakes between the two feed rollers 18 and 20 remain at least substantially constant over the entire angular range α .

The equation for the system can be easily established if the torques exerted on the arm 72 about the axis of rotation 70 are calculated as a function of the angle α and then set to zero for each angle α. From these equations, optimal values for the individual weights as well as the spring force and for the spring constant can then be determined. It is also conceivable that at least a good approximation to a constant clamping force can be achieved even without the additional weight 200.

The arm 72 must of course not be pivoted about the axis of rotation 70 of the opening roller 22. Instead, the articulation axis for the arm 72 can be chosen so that the clamping force remains constant as desired.

FIG. 7 shows an alternative embodiment of the pretensioning device 76.3, which here has the form of a gas pressure spring. Such a gas pressure spring has the property of exerting a constant tensioning force over a relatively long stroke.

It goes without saying that the arrangement shown in FIGS. 6 and 7 on one end of the feed rollers 18 and 20 on the other end of the feed rollers 18 and 20 is duplicated in a corresponding manner.

Finally, FIG. 8 shows a hydraulic solution to the task of generating a constant clamping force. Here too the feed rollers 18 and 20 are shown schematically. Instead of the previous spring pretensioning devices, the pretensioning device 76.4 is formed here by two piston-in-cylinder arrangements 210 and 212, which act on opposite ends of the axis of the feed roller 20, the piston rods 214, 216 of the two piston-in-cylinder arrangements, for example are articulated on the axis of rotation of the feed roller 20 and the cylinders 218, 220 of the two piston-in-cylinder arrangements are articulated on the frame of the associated flake shaft. During operation, there is pressure in the two cylinders, which is predetermined by the accumulator 222.

The accumulator 222 consists of a cylinder which is divided into two spaces 226 and 228 by means of a flexible membrane 224. The space 226 is filled with a gas, for example air, while the space 228 receives a hydraulic liquid which is connected via lines 230, 232 and 234 to the pressure spaces of the two cylinders 218, 220. Before the metering device is started up, an initial pressure is built up in the hydraulic system, specifically via a line 236, as will be explained in more detail below. A backflow via line 236 is not possible, however, as will also be explained in more detail later. Due to the set pressure, the piston-in-cylinder arrangements 210, 212 exert a predetermined force on the feed roller 20. If the position of the feed roller 20 changes due to the resulting flake flow, liquid is displaced, for example, from the cylinders 218, 220 into the space 228 of the accumulator 222, which leads to an increase in the volume of this space and a compression of the gas volume 226. As long as the gas volume is relatively large compared to the displaced liquid volume, the pressure set in the system remains at least essentially constant, so that a constant tensioning force on the Feed roller 20 is exerted, wherein the clamping force is also at least substantially independent of the actual position of the feed roller.

In order to put the system into operation, a hand pump 238 is provided in this embodiment, which draws hydraulic fluid from a container 240 and presses it into the pressure chambers 218, 220 and 228 via a check valve 242 and a distributor valve 246. The pressure established in these pressure rooms can be read off via the manometer 248. A relief valve 250 ensures that the pressure generated by the pump 238 does not exceed a maximum value, for example if the check valve 242 fails. Another relief valve 252 prevents excessive pressure from building up in the hydraulic pressure system. Should the valve 250 or the valve 252 bring about pressure relief due to an overpressure, the relieved liquid flows back via the line 254 into the container 240.

The distributor valve 246 is constructed here in such a way that the pressures can be built up at eight different flake shafts A to H with assigned metering devices. Two piston-in-cylinder arrangements 210 and 212 as well as an accumulator 222 and the associated lines are provided for each shaft. The individual biasing devices can be selected successively via the distributor valve 246. After the pressure setting in shaft E in the present example, the distributor valve is turned into a closed position in which the connection between the pump 238 and the individual pressure systems is interrupted. It is obvious that in this example a separate relief valve 252 must also be provided for each printing system.

It is also possible to use a small pump 238 to operate, which runs constantly. In this case, the accumulators 222 can be omitted. Instead, relief valve 252 is configured to maintain a constant pressure. Either a separate system can be provided for each well, or all wells can be connected to a pump at the same time, in which case only a single relief valve 252, which now functions as a pressure regulator valve, is required for all wells. In the latter case, all shafts A to H are connected to the pump 238 via a reusable distributor.

FIG. 9 now shows an embodiment according to the invention, which is very similar to the embodiment of FIG. 2, but with the feed roller 18 no longer being driven separately, but simply being freely rotatable. This embodiment is based on the knowledge that the flake flow resulting from the feed roller 20 exerts considerable frictional forces on the feed roller 18, especially when the surface of the feed roller 18 is not smooth, but has a surface texture which leads to an increased coefficient of friction, whereby these frictional forces are quite sufficient to drive the feed roller at a surface speed which corresponds to the speed of the flake flow or the surface speed of the feed roller 20.

Apart from this change, the design of the embodiment according to FIG. 9 largely corresponds to that of the embodiment according to FIG. 2, which is why the same reference numerals are used for the same parts, so that a separate description of these parts is not necessary. It is sufficient to point out that the axis of rotation 66 of the feed roller 18 is fixedly arranged, while the feed roller 20 is driven in the direction of travel 28. Conversely, it would also be possible to drive only the feed roller 18 and the other Feed roller 20 designed to rotate freely.

10, the arrangement of the opening roller 22 and the driven rotatable feed roller 20 has remained the same, which is why the same reference numerals have been retained for these parts. The feed roller 18 has, however, been replaced by a fixed chute 300 which, together with the feed roller 20, forms a conveyor gap 302 which has its minimum width at point 304.

In the embodiment of FIG. 11, the slide 300 has been replaced by a circumferential belt 306 which is guided around two deflection rollers 308 and 310. In this example, the upper deflection roller 308 is driven about the axis 312, in the direction of arrow 314, at a speed such that the surface running speed of the belt 306 in the direction of arrow 316 is equal to the surface running speed of the rotatable feed roller 20.

The arrangement of the rotatable feed roller 20 and the opening roller 22 corresponds to that of Figure 2, which is expressed by the use of the same reference numerals. This arrangement is not described here for brevity.

In the case of a driven revolving belt 306, it is not absolutely necessary to provide a deflection roller 310 in the lowest region of the loop formed by the belt. Instead, the tape can be guided over a triangular guide body 318, for example.

In this example, however, it is also possible not to drive the belt at all, but rather to move it under the frictional forces exerted by the floc stream. In such a case, it is desirable to provide a deflection roller 310 which can be freely rotated about the axis 320, in addition to the then also freely rotatable deflection roller 308, so that the friction preventing the free movement of the conveyor belt is kept as low as possible.

The minimum width 304 of the conveyor gap 302 is also arranged in this example at the lower end of the circulating belt.

The embodiment in FIG. 12 shows a driven feed roller 20.2 and a fixed feed trough 322. The feed roller 20.2 can be rotated about the axis of rotation 68.2 in the direction of arrow 28.2, and the axis of rotation 68.2 is carried at both ends by the respective link 72.2, the two links 72.2 ( only one of which can be seen in FIG. 12) are articulated at the upper end of the fixed feed trough 322 on the axis of rotation 324. In this example, the conveyor gap 302 has its minimum width at the point 304. This attachment of the feed roller 20.2 enables the minimum width 304 to be changed by pivoting movements of the handlebars in accordance with the arrows 74.2.

The pretensioning device 76.2 is designed according to FIG. 2, but reaches from above onto the lower end of the link 72.2 and thus forces the feed roller 28.2 in the direction of the feed trough 322.

13, both feed rollers 18 and 20 have been replaced by circulating belts 306 and 326. The arrangement of the circulating belt 306 around the two deflecting rollers 308 and 310 corresponds completely to the arrangement of the corresponding circulating belt 306 of FIG. 11, which is why this arrangement is provided with the same reference numerals and is not described here in detail.

The revolving belt 326 is designed approximately the same, that is, it runs around an upper deflection roller 328, which is driven and rotates about the axis 330. The circulating belt 326 is also guided over a lower deflection roller 332, which is arranged so as to be freely rotatable about the axis of rotation 334. At both ends of this axis 334 a pretensioning device 76.3 acts, which is essentially designed according to the pretensioning device of the previous figures, but with the additional measure that the parts 82 are connected to each other at both ends of the axis of rotation via a stable rod 336 to ensure that the gap width at the narrowest point 304 of the conveyor gap 302 remains constant over the entire axial length of the deflecting rollers 310 and 332. Such a rod 336 can also be provided in the other versions. The axis of rotation 330 of the deflection roller 328 is mounted with the axis of rotation 334 of the roller 332 on a common support body (not shown) so as to be pivotable about the axis 330.

In this example, either both circulating belts can be driven at the same surface running speed, or either only the rotating belt 306 or only the rotating belt 326 can be driven, and the other rotating belt can then freely rotate. In the case of freely rotating belts, it is preferred to design the lower deflection point as a freely rotatable roller. In the case of driven belts, however, deflecting bodies such as, for example, 318 or 338 can be provided, for example the deflecting body 318 being fixed and the deflecting body 338 being movably arranged. The mobility of the deflecting body 338 is limited to a pivoting movement about the axis 330. In this example, too, the minimum width 304 changes during operation, and the changes in this distance become apparent when the Surface circulation speed of the driven circulating belt or the driven rotating belts is taken into account.

In the end, FIG. 14 shows a further development of the embodiment according to FIG. 10, the rotatable feed roller 20 having been replaced with a circumferential belt 326 corresponding to FIG. 13. After the arrangement of the circulating belt 326 has been described in detail with reference to FIG. 13, a further description of the same subject can be dispensed with here. It should only be pointed out that the rotating belt 326 in this example must be a driven belt. In this example too, the width 304 changes during operation, and the changes in this width are taken into account when regulating the surface running speed of the circulating belt 326. This rotational speed is of course predetermined here, as in all other embodiments in which revolving belts are used, by the rotational speed of the associated driven deflecting roller, in this example 328.

FIG. 15 shows an embodiment in which the feed roller 20.5 is driven in the arrow direction 28.5 about a fixed axis of rotation 68.5. In this example, the feed roller 18 is replaced by a spring-loaded plate 370, that is to say the plate is prestressed against the flake mass in the direction of arrow 372 by means of a prestressing device 76.5. Guides 374 and 376, which are arranged below and above and on both sides of the plate 370, ensure that the plate can only move along the arrow direction 372. Here, too, the measuring device, which emits a signal that reflects the change in the distance 304 of the minimum width of the conveyor gap 302, is installed in the pretensioning device 76.5.

Instead of realizing the spring-loaded plate 370 in this form, it could also be designed as a leaf spring itself, in which case a separate sensor would be required in order to determine the changes in the distance 304 which occur during operation.

Finally, FIG. 16 shows a further modified arrangement of the embodiment according to FIG. 2, in which, however, both feed rollers 18.4 for a desired production ṁ _{should have} a fixed distance from one another and rotate about fixed axes of rotation 66.4 and 68.4, specifically in the directions of rotation caused by arrows 26.4 and 28.4 are specified. The opening roller 22 rotates about the likewise fixedly arranged axis of rotation 70.

The axis of rotation 68.4 of the feed roller 20.4 is supported at its two ends by approximately triangular plates 340 in front view (only one of which can be seen in FIG. 16), the two plates being connected to one another via connecting rods (not shown). The plates 340 are in turn arranged to be pivotable about a fixed axis of rotation 342, as indicated by the double arrow 344. In operation, however, a fixed position of the triangular plates 340 and therefore also the axis of rotation 68.4 of the feed roller 20.4 is selected. This is done via a threaded spindle 346, which is passed through a solid part 348 with an internal thread. The part 348 is arranged in a machine-fixed manner. A handwheel 350, which can also be replaced by a motor drive, enables the threaded spindle 346 to be rotated, as a result of which the position of the triangular plates 340 can be determined. Since a corresponding spindle arrangement is also provided for the second triangular plate (not shown), the two spindle drives are to be coupled to one another, which can be done, for example, via the rotating belt 352.

At the end of each threaded spindle 346 there is a yoke 354, the legs 356 and 358 of which are arranged on the respective side of a tab part 360 of the associated triangular plate 340. Between each leg 356 and 358 and the tab 356 there are load cells 362 and 364 which are connected to the computer via lines (not shown). In operation, the two feed rollers convey the flake material through the conveyor gap 302 and through the location 304 of the minimum width, and a force P acts on the feed roller 20.4, which tries to pivot the triangular plates 340 about the axis of rotation 342. Actual pivoting does not occur because it is prevented by the spindle-yoke arrangement. The load cells 362 and 364 enable the size of this force to be determined by the computer, which also takes into account the geometric circumstances.

The fluctuations in this force correspond to the fluctuations in the density of the flake flow at point 304 and are processed by the computer to regulate the rotational speed of the feed roller 20.4 and, if appropriate, the feed roller 18.4, if this roller is also or alternatively driven, so that the desired mass flow ṁ _{should be} maintained becomes.

If one wishes to change the production from the shaft, this can be done only by changing the rotational speed of the feed roller 20.4 and, if necessary, the feed roller 18.4. However, in order to create a wider adjustment range, the minimum width 304 can be changed or set by means of the spindle 346, so that the speed changes of the feed rollers can be kept within predetermined limits, regardless of the production intended in each case ṁ _should .

Finally, it should be noted that the embodiment of FIG. 16, in which the distance 304 is kept constant, and the magnitude of the force which tries to push the feed devices apart, can be used in a corresponding manner in all other embodiments instead of the described preloading devices.

Although the pre-tensioning devices 76, 76.3 and 76.4 are shown in FIGS. 9 to 14 as in the embodiment of FIG. 2, it is understood that in practice these pre-tensioning devices should preferably be realized by gas pressure springs or hydraulic arrangements in order to independently of the pre-tensioning force Change the minimum width 304 to keep constant. Also, in the new exemplary embodiments, the geometry can in part be selected such that compensating forces occur which, even when using a conventional compression spring, lead to a force which, with adjustment of the one feed device, does not result in a change in the preload force or only to a small extent.

It is understood in all embodiments that plates are provided on the ends of the feed devices or the opening roller, which limit the flake mass or the flake flow on the sides of the conveying gap.

Claims (11)

1. A dosaging method for supplying predefinable quantities of fibre flocks (60) per time unit by means of two feed devices arranged at the lower end of a flock chute and forming between them a conveying gap, with preferably an opening roller (22) being arranged below the feed devices, whereby the feed devices consist either of

   a) a driven rotatable feed roller (20) and a chute (300) situated opposite thereof, or

   b) a driven rotatable feed roller (20) and a driven or freely revolving belt (306) situated opposite thereof, or

   c) two mutually opposite revolving belts (306, 326), whereby at least one of the belts (306) is driven and the other either revolves or is also driven, or

   d) a driven revolving belt (326) and a chute (300) situated opposite thereof, or

   e) a driven rotatable feed roller (20) and a further feed roller arranged freely rotatable and situated opposite thereof, or

   f) a driven rotatable feed roller (20.2) and a feed trough situated opposite thereof (322),

   whereby in all possible embodiments a) to f) the conveying gap can be converged towards a minimal width and at least one of the feed devices is pretensioned in the direction towards the other feed device and it is movable away from it under the pressure of the flocks, this being so in such a way that the distance between the two feed devices is changed in the sense of a change of the minimum width (x) of the conveying gap, that the minimum width of the conveying gap or a value proportional thereto is determined and that the surface speed (u) of the driven feed device or feed devices is controlled in such a way that at least the mean value of the product of this width and the surface speed remain constant.
2. A method as claimed in claim 1, characterized in that the control of the surface speed is made in such a way that the product (u . x) is integrated over a predefined time interval (t₂ - t₁), that therefrom the momentary production (m) in accordance with the equation

   

   is formed, whereby K represents a constant, that a comparison between the actual value (ṁ) of the momentary production and its set value (ṁ_set-point) is carried out, and that therefrom a new surface speed is calculated for the next time interval in the sense of an approach of the next value of the momentary production (ṁ) to its set value (ṁ_set-point).
3. A method as claimed in claim 2, characterized in that the surface speed (u) is controlled within every time interval towards a respective constant value.
4. A dosaging apparatus for supplying predefinable quantities of fibre flocks (60) per time unit, in particular for carrying out the method as claimed in one of the previous claims, by means of two feed devices arranged at the lower end of a flock chute and forming between them a conveying gap, with preferably an opening roller (22) being arranged below the feed devices, whereby the feed devices consist either of

   a) a driven rotatable feed roller (20) and a chute (300) situated opposite thereof, or

   b) a driven rotatable feed roller (20) and a driven or freely revolving belt (306) situated opposite thereof, or

   c) two mutually opposite revolving belts (306, 326), whereby at least one of the belts (306) is driven and the other either revolves or is also driven, or

   d) a driven revolving belt (326) and a chute (300) situated opposite thereof, or

   e) a driven rotatable feed roller (20) and a further feed roller arranged freely rotatable and situated opposite thereof, or

   f) a driven rotatable feed roller (20.2) and a feed trough situated opposite thereof (322),

   whereby in all possible embodiments a) to f) the conveying gap converges towards a minimum width, whereby a pretensioning device (76, 76.2, 76.3, 76.5) is provided which pretensions at least one of the feed devices in the direction towards the other feed device, whereby at least one of the feed devices is arranged so that it is movable away from the respective other feed device under the pressure of the flocks, a path measuring device is provided which determines the distance which arises during the operation of the flock conveyor between the two feed devices at the position of minimum width or a value proportional to this, and a control unit is provided which controls the surface speed (u) of the movable feed device(s) according to the determined distance (x) in the sense of reaching a predefined set value (ṁ_set-point) of the momentary production (ṁ).
5. A dosaging apparatus as claimed in claim 4, characterized in that in an arrangement, in which the feed devices consist of a driven rotatable feed roller (20) and a chute (300) situated opposite therefrom and forming a conveying gap with it, the chute is arranged as a spring plate which owing to its spring arrangement can be pressed away from the rotatable, but rigidly arranged feed roller (20).
6. A dosaging apparatus as claimed in claim 4, characterized in that the pretensioning device (76, 76.2, 76.3, 76.5) is formed by at least one spring (84) or a tensioning element whose force remains substantially constant within the predefined shifting path.
7. A dosaging apparatus as claimed in claim 4, characterized in that the pretensioning device (76.3) is formed by at least one gas-pressure spring.
8. A dosaging apparatus as claimed in claim 4, characterized in that the pretensioning device (76.2) is formed by at least one spring (84), that at least one one counter-weight is provided to offset at least partially the reduction in the tensioning force with decreasing distance between the two feed devices, whereby the counter-weight or at least a part thereof is formed optionally by said feed device per se in the event of suitable suspension of the one feed device.
9. A dosaging apparatus as claimed in claim 4, characterized in that the pretensioning device (76.4) is a hydraulic pretensioning device which is formed, for example, either by a displacement system actuated by the movement of the one feed device and an acculumator (222) connected thereto or by a compensated arrangement with a pressure system generating an at least substantially constant pressure.
10. A dosaging apparatus for supplying predefinable quantities of fibre flocks per time unit by means of two feed devices arranged at the lower end of a flock chute and forming between them a conveying gap, with preferably an opening roller being arranged below the feed devices, whereby the feed devices consist either of

    a) two driven feed rollers (20, 18) situated opposite of one another, or

    b) a driven rotatable feed roller (20) and a chute (300) situated opposite thereof, or

    c) a driven rotatable feed roller (20) and a driven or freely revolving belt (306) situated opposite thereof, or

    d) two mutually opposite revolving belts (306, 326), whereby at least one of the belts (306) is driven and the other either revolves or is also driven, or

    e) a driven revolving belt (326) and a chute (300) situated opposite thereof, or

    f) a driven rotatable feed roller (20) and a further feed roller arranged freely rotatable and situated opposite thereof, or

    g) a driven rotatable feed roller (20.2) and a feed trough (322) situated opposite thereof,

    whereby the relative position of the two feed devices with respect to one another, with simultaneous measurement of the force (P) or a value proportional to this which presses the two feed devices apart, is kept at least substantially constant, with the surface speed (u) of the driven feed device(s) being controlled in such a way, by taking into account the changing force, that at least the mean value of the product (u . P) of the surface speed and the force remains constant.
11. A dosaging apparatus for supplying predefinable quantities of fibre flocks per time unit, in particular for carrying out the method as claimed in claim 10, by means of two feed devices arranged at the lower end of a flock chute and forming between them a conveying gap, with preferably an opening roller being arranged below the feed devices, whereby the feed devices consist either of

    a) two driven feed rollers (20, 18) situated opposite of one another, or

    b) a driven rotatable feed roller (20) and a chute (300) situated opposite thereof, or

    c) a driven rotatable feed roller (20) and a driven or freely revolving belt (306) situated opposite thereof, or

    d) two mutually opposite revolving belts (306, 326), whereby at least one of the belts (306) is driven and the other either revolves or is also driven, or

    e) a driven revolving belt (326) and a chute (300) situated opposite thereof, or

    f) a driven rotatable feed roller (20) and a further feed roller arranged freely rotatable and situated opposite thereof, or

    g) a driven rotatable feed roller (20.2) and a feed trough (322) situated opposite thereof,

    whereby in all possible embodiments a) to g) the conveying gap converges towards a minimum width, whereby the relative positions of the two feed devices with respect to one another are to remain substantially constant for a selected production (ṁ_set-point), a force measuring device is provided so as to measure the force (P) which tries to press the two feed devices apart and a control unit is provided which controls the surface speed (u) of the driven feed device(s) owing to the force determined in the sense of reaching the predefined set value (ṁ_set-point) of the momentary production (ṁ).

Images