EP0737762A1 - Apparatus for feeding fiber material to a textile machine, especially a carding machine - Google Patents

Abstract

The feed system for a carding machine has a number of feed channels distributed over the whole length (L) of the hopper (7). Each delivers fibre material over a defined section (1) of the hopper length (L). Pref. the feed system has a distributor with an inlet to take fibre material with a carrier air stream. The outlets are a number of channels for the distributed material. The distributor divides the incoming fibre material and can block all the distribution outlet openings except one, in succession along them all. The delivery to the distributor channels is through a fan which draws the material into the distributor and blow it out at the channels. The material is divided in the distributor by a rotating collar round the fan rotor. The collar is rotated continuously, or its movement is incremental with a stopper time to give a divided feed to at the distribution channels, or it can vary between the channels according to the material level in the hopper, to top up low sections.

Description

The present invention relates to a device allowing the supply of fibrous material to a textile machine. It relates more particularly to the pneumatic loading of the reserve chimney of such a device. The feed device of the invention is intended, without limitation, to be used upstream of a card.

Currently, to continuously feed a card with fibrous material, a feed device is used comprising an upper chimney, called a reserve chimney, which is fed in its upper part with fibrous material, in the form of flakes. At the outlet of this reserve chimney, several cylinders are mounted for rotation, making it possible to take up the fibrous material stored in the reserve chimney and to convey it to the entry of the card. These cylinders will for example consist of a food cylinder located in the extension of the reserve chimney, and a breaker cylinder adjacent to the food cylinder, and driven in rotation with a higher speed.

In the devices known to date, the reserve chimney is continuously supplied by means of a pneumatic loading device which comprises a single loading duct conveying the transport air and the fibrous material, up to the upper part of the fireplace. At least one of the walls of the reserve chimney is provided with transport air exhaust openings, which allow the fibrous material to be separated from the air. Below this separation zone, the fibrous material accumulates in the reserve chimney.

German patent application DE.A.3916986 describes an installation which allows the formation of a fibrous sheet in three superimposed layers, from three reserve chimneys supplied in parallel, and successively arranged above a conveyor belt. The fibrous material is supplied to the three chimneys pneumatically by means of three loading conduits, at the rate of one single loading duct by reserve chimney.

The British patent application GB.A.1014689 describes a device for the pneumatic parallel supply of a plurality of reserve chimneys each arranged downstream of a card. This device comprises a main distribution conduit, which makes it possible to convey the fibrous material at the level of each reserve chimney, and which comprises at the bottom a plurality of distribution openings, at the rate of a distribution opening by chimney of reserve, each distribution opening communicating with the upper part of the corresponding reserve chimney. In the lower part of each reserve chimney is provided a conveyor belt making it possible to convey the fibrous material coming from the reserve chimney to the entry of card.

In all known supply devices, a reserve chimney has a rectangular type section, that is to say a section whose dimension in a given direction is greater. This dimension will be called in the rest of this text, "width" of the reserve chimney, the other dimension of the section in the transverse direction being the "depth" of the chimney. In general, the width of the chimney will correspond to the entry width of the card. The width of a chimney can therefore in practice reach several meters, while the depth of the chimney is usually of the order of a few centimeters.

In the aforementioned type of feeding device, the regularity of the level of fibrous material over the entire width of the reserve chimney has a preponderant effect on the regularity of the thickness of the fibrous web which is obtained at the outlet of the card. One of the main problems faced by the manufacturers and users of the aforementioned supply devices lies in the difficulty of filling the reserve chimneys while maintaining a constant level of fibrous material over the entire width of the chimney.

To try to solve this problem, we have so far sought to disperse the flakes of fibrous material at the inlet of the reserve chimney and to redistribute them homogeneously over the entire width of the chimney, by appropriately channeling the transport air inside the chimney. This air channeling is for example obtained by closing, in an appropriate sequence, the exhaust openings of the transport air. This type of solution is in particular implemented by the process of European patent application EP 460 000 from the company HERGETH HOLLINGWORTH GMBH, in which a pulsating operation of the transport air is produced inside the reserve chimney . According to another very similar variant, it is also known to interpose, on the path of the fibrous material, inside the reserve chimney, a plate provided with openings which can be closed at will. Similarly, in the British patent application GB.A.1014689, it is taught to use a perforated belt for the conveyor belt at the outlet of the reserve chimney.

In practice, the use of transport air to effect a homogeneous distribution of the fibrous material over the entire width of the reserve chimney is not reliable. In the best of cases, during filling, there is a significant defect in fibrous material at each end of the chimney; this defect in material is reflected at the end of the card by a fibrous veil having thinner edges; to obtain a fibrous web of uniform thickness, it is necessary either to cut the edges of the web, or possibly to supply the carding input only with the middle part of the material from the chimney; this necessarily results in a loss of material each time, with the first solution being an additional cutting operation. In the worst case, the filling of the reserve chimney results in a totally irregular profile of the fibrous material over the entire width of the chimney, including at its central part; in this case, the fibrous veil produced at the outlet of the card is unrecoverable.

The main purpose of the present invention is to provide a feeding device for a textile machine, and in particular for a carding machine, which, unlike the devices of the prior art, generally makes it possible to reliably control the level profile of the fibrous material inside the reserve chimney , and which more particularly ensures a level of fibrous material which is constant over the entire width of the reserve chimney.

This object is perfectly achieved by the supply device of the invention, which in known manner comprises a reserve chimney which is supplied in the upper part with fibrous material by a pneumatic loading device.

Typically according to the invention, the loading device comprises a plurality of loading conduits which are distributed over the entire width L of the chimney, and which each have the function of supplying the chimney with fibrous material, over a limited portion l of its width.

The invention results from the observation which has been made that the action of the transport air on the flakes of fibrous material varies as a function of the density of these flakes, which is completely heterogeneous. As a result, the control of the transport air flow does not make it possible to overcome differences in the density of the flakes of fibrous material, and thereby to effect a homogeneous redistribution of these inside the reserve fireplace. On the contrary, in the device of the invention, a forced redistribution of the fibrous material is advantageously carried out at the entrance to the chimney, by bringing said material to a limited area of the chimney where it is desired that it accumulates, the fibrous material not undergoing dispersion throughout the width of the chimney, unlike previous devices. In addition, by controlling the passage of the material in a loading duct, one acts locally on the level of material in the reserve chimney; the combination of these localized actions makes it possible to reliably control the regularity of the level of material over the entire width of the chimney, by overcoming the varied density of the flakes introduced.

In a preferred embodiment, the reserve chimney is divided, in its upper part, into a plurality of compartments of width l, which are separated by watertight partitions, which are each supplied with fibrous material by a single loading duct, and at the level of which openings are provided for the exhaust of the air for transporting the fibrous material. This advantageously achieves a physical separation of the inlet of the reserve chimney into several aeraulically independent loading lanes.

In the context of the invention, it is theoretically conceivable to produce a supply device in which the loading conduits are completely independent of one another, both from the point of view of their supply of transport air and of their supply in fibrous material. In practice, the implementation of this solution on the industrial level is very difficult. For this reason, in a preferred embodiment, the feeding device of the invention further comprises a distribution system, which is supplied at the inlet by pneumatic means with a single flow of fibrous material, which comprises at the outlet a plurality distribution conduits each connected to a loading conduit, and which has the function of distributing the flow of fibrous material between the various loading conduits. In practice, this distribution system will be placed as close as possible to the reserve chimney.

In a first alternative embodiment, the distribution system will have the function of simultaneously feeding all the loading conduits, from the flow of fibrous material which it receives at the inlet. The distribution system may in this case consist of a fan with several outlets, combining the functions of transport and separation of the fibers; it may also be a static or dynamic fiber separator; in which case the fiber transport function will be ensured by an auxiliary fan.

In a second variant, the distribution system will supply alternately each loading duct one after the other. In this case, the distribution system comprises means for routing the flow of fibrous material, which have the function of closing all the distribution conduits, except for one of them, and this alternately for each distribution conduit.

Preferably, the distribution conduits are distributed over the periphery of the distribution system, which further comprises a central fan which sucks the fibrous material at the inlet of the distribution system and delivers it towards the distribution conduits. In this case, in the case of an alternative distribution system, the switching means will advantageously consist of a rotary ferrule, which surrounds the rotor of the central fan, which has an opening for the passage of the fibrous material, and which can be positioned in rotation so that its opening coincides with any one of the distribution conduits, the other distribution conduits being closed by the ferrule.

The ferrule can be driven in continuous rotation, or on the contrary have an incremental rotational movement. In the second case, when the ferrule is brought into a given switch position, it will be locked in rotation for a predetermined time.

In the case of an incremental rotational movement, this can be achieved, with a time for stopping the ferrule in a switch position which is identical for all the loading conduits and which will advantageously be adjustable. On the contrary, the stop time of the ferrule can advantageously be variable from one distribution duct to another and be controlled by the height of fibrous material in the reserve chimney at the level of the corresponding loading duct. This variant makes it possible, by acting on the supply time of a loading conduit, to locally correct the level of fibrous material in the reserve chimney, on the basis of an actual measurement of the profile of this level.

• La figure 1 est une représentation schématique d'un dispositif d'alimentation avec un système de répartition en amont de la cheminée de réserve,
• La figure 2 est une vue en perspective de la partie supérieure de la cheminée de réserve de la figure 1,
• La figure 3 est un exemple particulier de réalisation d'un système de répartition à huit sorties, permettant l'alimentation alternative de la cheminée de réserve de la figure 2,
• et la figure 4 est une représentation schématique de l'intérieur de la cheminée de réserve du dispositif de la figure 1, en cours de remplissage.

Other characteristics and advantages of the invention will appear more clearly on reading the description which will be given of a particular embodiment, which description is given by way of nonlimiting example and with reference to the appended drawing in which:

• FIG. 1 is a schematic representation of a supply device with a distribution system upstream of the reserve chimney,
• FIG. 2 is a perspective view of the upper part of the reserve chimney of FIG. 1,
• FIG. 3 is a particular embodiment of a distribution system with eight outlets, allowing the alternative supply of the reserve chimney of FIG. 2,
• and Figure 4 is a schematic representation of the interior of the reserve chimney of the device of Figure 1, during filling.

There is shown in Figure 1 a device for continuously feeding a card (not shown) with raw fibrous material, stored in bulk in a silo 1. This device comprises a centrifugal fan 2 which allows to suck the material fibrous material stored in the silo 1 and forcing it back into a main transport conduit 3. This transport conduit 3 pneumatically conveys the fibrous material to a distribution system 4, comprising eight peripheral outlets 5. Each outlet 5 is connected to a loading duct 6. For the sake of clarity, in FIG. 1, only one of these eight loading ducts 6 has been shown. The loading conduits 6 open into the upper part 7a of a reserve chimney 7, being distributed over the entire width of the chimney 7, as will emerge more clearly from the detailed description which will be given below of the chimney reserve 7, with reference to FIG. 2. At the outlet of the reserve chimney 7 is rotatably mounted a food cylinder 8 which makes it possible to convey the fibrous material 9 accumulated in the reserve chimney 7 to a second lower chimney 10 A breaking cylinder 12 is further mounted adjacent to the food cylinder 8 and is rotated in the same direction as the food cylinder 8. In known manner, the outlet 10 a from the lower chimney 10 will be positioned directly upstream of the first cylinder of a card (not shown).

Referring to Figure 2, the reserve chimney 7 has a general shape of a rectangular parallelepiped, of width L and depth e . The upper part 7 a of the reserve chimney 7 is divided, over its entire width L , into eight compartments 13 of width l . Each compartment 13 is separated from the compartment which is adjacent to it by a watertight partition 14. The upper part 13 a of each compartment 13 also forms a bend, which is extended by a connector 15, making it possible to connect a loading conduit 6 to section circular, at the entrance to each compartment 13 of rectangular section. The inlet diameter d of each connector 15 therefore corresponds to the diameter of a loading conduit 6. The bottom wall 16 of each compartment 13, which is located opposite the connector 15 is provided in its lower part 16 a openings 17 for the exhaust of the air for transporting the fibrous material.

In the supply device which has just been described, the distribution system 4 has the function of distributing the flow of fibrous material which it receives at the inlet, destined for the eight loading conduits 6. At the outlet of each loading 6, the fibrous material is introduced continuously into each compartment 13 at the level of which it undergoes local dispersion over the entire width l , then comes to accumulate on the fibrous material previously introduced. The angled shape of the upper part of each compartment is intended to prevent clogging of the fibers, by creating localized air turbulence. At each compartment 13, the air for transporting the fibrous material is evacuated through the exhaust openings 17.

In a specific example of embodiment, the diameter d , the total width L , the width l and the depth e were respectively 200mm, 4m, 500mm, and 150mm.

Two main variants can be envisaged for the distribution system 4. In a first variant, it has the function of simultaneously supplying all the loading conduits 6 with the flow of fibrous material which it receives at the inlet. In a second variant, the function of the distribution system is to supply a single loading duct 6 given at a given instant. An exemplary embodiment of this second variant will now be described.

If we now refer to the particular embodiment of the distribution system of Figure 3, it comprises an outer casing forming an eight-pointed star 18 a , 18 b , 18 c , 18 d , 18 e , 18 f , 18 g , 18 h , and comprising a central opening 19 for the pneumatic introduction of the fibrous material. This opening 19 is therefore connected to the main transport conduit 3 of FIG. 1. Each branch of the star constitutes a peripheral distribution conduit making it possible to convey the fibrous material from the opening 19, to the corresponding outlet 5 of the distribution system 4. Inside the outer casing of the distribution system 4 is mounted a fan 20 comprising a radial rotor 21 with straight blades. This rotor 21 is centered on the opening 19 and is surrounded by a pivoting ferrule 22. This ferrule 22 is of cylindrical shape, with on its periphery an opening 23 for the passage of the fibrous material. This ferrule 22 can be positioned in rotation according to eight switch positions, in each of which its peripheral opening 23 is opposite one of the distribution conduits. In the switch position illustrated in FIG. 3, the fan 20 sucks the fibrous material through the opening 19, and discharges this fibrous material in the direction of the distribution duct 18 a , the other distribution ducts being closed by the ferrule 22 .

In a particular variant embodiment, the rotational movement of the ferrule is incremental, and takes place cyclically in the direction of the arrow F, with a variable stopping time in each switching position as will be described below. Each compartment 13 of the reserve chimney 7.

Advantageously, the stopping time of the ferrule 22 at each distribution conduit 18 a , 18 b , 18 c , 18 d , 18 e , 18 f , 18 g , 18 h is a function of the height of fibrous material in the compartment 13 corresponding. Referring to Figure 4, each compartment 13 is provided with a sensor 24 for measuring the level of material in the compartment. When the ferrule 22 arrives in a given switching position, it remains locked in rotation until the level of the fibrous material locally reaches the sensor 24 of the compartment 13 which is being filled. This sensor then triggers the incremental rotation of the ferrule to the next switch position, in order to supply the next compartment 13 if necessary.

In the example of FIG. 4, the shell 22 is hypothetically in a switching position allowing the filling of the first compartment 13 furthest to the left, the filling of the compartments being carried out cyclically from left to right. Given the level of material detected by the sensor 24 in this first compartment 13, the shell is rotated to the next switching position, in order to fill the adjacent compartment 13. This second compartment being already sufficiently filled, the ferrule 22 immediately passes into the following position, where it remains locked in rotation until the level of material in this third compartment reaches the sensor 24, etc.

Thanks to the above-mentioned servo-control of the rotation of the ferrule 22, the level of material in the chimney is automatically kept substantially constant over the entire width L of the chimney. As a result, the pressure exerted by the material on the food cylinder 8 is uniform over the entire length of this cylinder, which allows a uniform supply of the card over its entire width, and thereby obtain at the outlet of cards a fibrous veil of constant thickness. Of course, by playing on the height position of the sensors 24, it is it is also possible to voluntarily produce a fibrous web having a particular profile in thickness.

The invention is not limited to the particular embodiment which has just been described. It is possible in particular to produce a device in which the upper part of the reserve chimney is not divided into several compartments. It is also possible to envisage other types of servo-control of the rotation of the ferrule, as a function of the height of fibrous material detected locally at each loading duct. The ferrule 22 may finally be replaced by a regulation system performing the same switching function, such as for example a plurality of electro-mechanically controllable closing valves, and making it possible to close the distribution conduits on demand.

Claims (10)

A feeding device of a textile machine of the type carding machine or similar, wherein a reserve funnel (7) is fed in the upper part (7 a) with the fibrous material by a pneumatic loading device, characterized in that the loading device comprises a plurality of loading conduits (6) which are distributed over the entire width L of the chimney (7), and which each have the function of supplying the chimney (7) with fibrous material, over a limited portion l of its width L. A feeding device according to claim 1 characterized in that in its upper portion (7a), the reserve funnel (7) is divided into a plurality of compartments (13) of width l, which are separated by bulkheads ( 14), which are each supplied with fibrous material by a single loading conduit (6), and at the level of which are provided openings (17) for the exhaust of the air for transporting the fibrous material. A feeding device according to claim 1 characterized in that the upper part (7a) of the chimney (7) is bent. Feeding device according to claim 1 characterized in that the loading device comprises a distribution system (4) which is supplied at the inlet pneumatically with a single flow of fibrous material, which comprises at the outlet a plurality of distribution conduits (18 a , 18 b , 18 c , 18 d , 18 e , 18 f , 18 g , 18 h ) each connected to a loading duct (6), which has the function of distributing the flow of fibrous material between the different loading conduits (6). Feeding device according to claim 4 characterized in that the distribution system comprises means for directing the flow of fibrous material which have the function of closing all the distribution conduits, except one of between them, and this alternately for each distribution conduit. Feeding device according to claim 4 characterized in that the distribution ducts (18 a , 18 b , 18 c , 18 d , 18 e , 18 f , 18 g , 18 h ) are distributed over the periphery of the distribution system (4), which further comprises a central fan which sucks the fibrous material at the inlet (19) of the distribution system (4), and discharges it in the direction of the peripheral distribution conduits (6). Feeding device according to claims 5 and 6 characterized in that the switching means consist of a rotary ferrule (22) which surrounds the rotor (21) of the fan (20), which has an opening (23) for passage of fibrous material, and which can be positioned in rotation so that its opening (23) coincides with any one (18a) of the distribution conduits, the other distribution conduits ( 18b , 18c , 18d , 18 e , 18 f , 18 g , 18 h ) being closed by the ferrule. Feeding device according to claim 7 characterized in that the ferrule is driven in continuous rotation. Feeding device according to claim 7 characterized in that the rotational movement of the ferrule is incremental with a stop time of the ferrule in a given switch position which is identical for all the distribution conduits. Feeding device according to claim 7 characterized in that the rotational movement of the ferrule is incremental with a stop time of the ferrule in a given switch position which is variable from one distribution duct to the other , and which is controlled by the height of fibrous material in the reserve chimney at the level of the corresponding loading duct (6).

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