EP0848091A1 - Impurity removing arrangements - Google Patents

Abstract

In the assembly to separate dirt particles from fibres carried in an air stream, at least one condition is met to limit the air turbulence downstream of the separation edge (24), in the flow direction.

Description

The invention is concerned with an improvement in dirt separation devices for use in the blowroom or in the carding machine of a spinning mill.

State of the art:

It is well-known practice today on the drum shields of both revolving covers and also to be used for fixed-carding machines with "sucked-off knives" Devices are able to remove dirt particles from the processed material, while the fibers are carried on with the drum set. To suitable drum shuttering segments are in EP-A-431 482 and EP-A-366 918 described. Attaching knives to formwork segments is also in US-C-4,314,387 as well as shown in US-C-5,530,994, the latter document being related is of particular importance with the present invention because the introduction of a Air flow between a segment and an element attached to it is provided. Similar air flows are explained in EP-A-366 692 and EP-A-338 802, while EP-A-387 908 the importance of the air balance for the cleaning effect stressed. In all of these cases, the introduction of the airflow is apparently only for that designed to improve the removal of dirt, taking air turbulence into account is taken or even desired. They also deal exclusively with the area upstream of the knife in the fiber transport direction.

The present invention is based on the knowledge that the air flows are not only for the removal of dirt but also in connection with the Nissen formation play an essential role. In the latter context it is Turbulence is not desirable. In addition, the area downstream of the knife just as important as the area upstream from the Knife. These findings apply not only to dirt separation devices in the Card, but also in other places in the spinning mill, e.g. in cleaning machines, the excrement knives (e.g. after the single figure of the DE-A-44 41 425).

The state of the art is therefore based on "knives" (also called "blades") , a "knife" typically having a blade facing a rotating roller (e.g. a card reel) is adjustable. But it is also known to have a similar function through an edge (also "separator" or Called "excretion edge"), this edge being formed on an element is that is not necessarily designed as an adjustable "knife". The invention is also applicable in such arrangements. To avoid cumbersome repetitions in the Avoiding description is referred to below as an edge, whereby this term includes the special form "knife" or "blade".

The invention:

The object of the invention is to control the air flow downstream of one Edge provided with suction to improve. This enables the Air turbulence reduces the formation of nits in fiber processing machines will. But it can also improve dirt removal on and for be achieved. The invention can be one or the other or both serve these purposes.

The invention provides a fiber processing machine with a cutting edge, both fiber and air in a substantially predetermined Direction of transport past the edge and dirt particles selectively to be removed from the fiber / air stream by means of the edge. The invention is characterized in that at least one measure has been taken to prevent the Influence air currents in the zone downstream of the knife. The said Measure can be taken in such a way that air turbulence downstream (in the Transport direction) from the edge or even (if possible) eliminated. With in other words, the most laminar possible downstream of the edge Flow pattern are generated or maintained. Alternatively or additionally the said measure can be taken in such a way that through the edge separated air can be removed essentially without recirculation.

The measure preferably consists in the air being discharged through the edge is at least partially replaced by newly introduced air. The newly introduced air conveniently flows into the zone adjoining the edge, e.g. within 50 mm downstream of the edge and preferably within a distance of less than 20 mm. Flows in a solution the newly introduced air just behind the edge into the fiber / air flow.

The invention is particularly, but not exclusively, for use in a Machine provided which comprises a rotatable roller (drum or drum), the fiber / air flow in a "working gap" between the circumference of the roller and a surrounding formwork flows. The edge is in the formwork intended. The selectivity of the excretion is then achieved in that the Roller is provided with a fiber-holding set, while the centrifugal force Dirt particles, which are heavier than the fibers, radially outwards (against the Formwork) is pressing. The working gap usually extends over almost that whole axial length (over the "working width") of the roller. The arrangement can be such be taken that the effective cross section of the working gap downstream of the edge undergoes an expansion, the degree of expansion at best not in the can be determined in advance, e.g. if the position of the edge in the radial Direction opposite the roller can be set.

According to the invention, therefore, means are provided, for example, to air into the room to flow in downstream of the edge. The means mentioned can be such that air be arranged over substantially the entire working width can flow in, preferably as evenly as possible over the entire working width. The edge is usually formed on an element that is in the formwork of the Roller is suspended. The formwork should now be formed in such a way that the The required air flow is enabled, e.g. so that a Flow channel between the element and a part adjacent to it remains free. If the suspension has to bridge this channel, this is preferred ensured that the partial currents separated from each other by the suspension Connect (again) before they flow into the room.

The arrangement is preferred with regard to the inflowing amount of air self-adjusting, i.e. (e.g.) that there is no need to work with blown air. If the free flow cross-section of the channel is dimensioned sufficiently required air flow due to a negative pressure in the room downstream of the Edge.

The flow channel can be formed or arranged in such a way that when Incoming air enters the room essentially in the direction of transport flows.

Embodiments of the invention are based on the schematic Drawings described as examples.

Fig. 1 eine Kopie der Figur 1 aus EP-A-431 482,

Fig. 2 einen Schnitt durch eine bekannte Vorrichtung zur Verwendung in einer Karde nach der Figur 1,

Fig. 3 einen entsprechenden Schnitt durch eine erste Anordnung nach dieser Erfindung,

Fig. 4 ein Detail, in der Richtung des Pfeils P in Fig. 3 betrachtet,

Fig. 5 einen Schnitt durch eine zweite Anordnung nach der Erfindung, und

Fig. 6 eine schematische isometrische Darstellung der bevorzugten Absaugung in einem Gerät nach Fig. 3 oder Fig. 5.

It shows:

1 shows a copy of FIG. 1 from EP-A-431 482,

2 shows a section through a known device for use in a card according to FIG. 1,

3 shows a corresponding section through a first arrangement according to this invention,

4 shows a detail, viewed in the direction of arrow P in FIG. 3,

Fig. 5 shows a section through a second arrangement according to the invention, and

FIG. 6 shows a schematic isometric illustration of the preferred suction in a device according to FIG. 3 or FIG. 5.

1 shows a schematic side view of the reel 30 of a card, the end parts 32, 34 of a revolving flat aggregate, which is the main carding zone defined, a breeze (the lickerin) 36, and a customer 38. The direction of rotation of the drum 30 about its axis A is indicated by the arrow D.

In the pre-carding zone, between the beater 36 and the adjacent end 34 of the Revolving cover aggregate, there is a dirt separating device 39 and a formwork segment 40 preceding this device. The device 39 comprises two drum shuttering segments 42, 44, which are described in more detail below to be discribed.

The post-carding zone, between the other end 32 of the revolving flat aggregate and the pickup 38, is with a further dirt separating device 46 provided which is interchangeable with the device 39 and therefore not individually is described. Finally, it is in the sub-carding zone (between the 1 and a further dirt separating device 48 and four drum shuttering segments 50. The segments 50 are with the segment 40 interchangeable. The device 48 can be divided into two segments 50 can be replaced, but (if maintained) also according to this invention be formed.

In FIG. 2, the outer surface of the drum 30 is identified by the reference number 31 indicated, their direction of rotation is again indicated by the arrow D. The Shell surface 31 carries a set, but this is not shown here because it is for the Explanation does not play an essential role and is well known by the expert. The According to FIG. 2, device 39 comprises a first formwork segment 42, which as Carrier for carding elements 12 provided with trimmings is formed, and a second Formwork segment 44, which is provided as a support for further sets Elements 16 is formed. The above-mentioned working gap is indicated at 10, with a Separation gap 18 between the segments 42, 44 remains open and in the working gap 10 opens. The separation gap 18 is covered by a hood 20 which is attached to one End (not shown in Fig. 2) is connected to a suitable suction to discharge waste which has been discharged through the gap 18.

The second segment 44 is provided with a knife 22 which is inserted into the working gap projecting separating edge 24. The knife 22 is by screws 25 (only one screw 25 visible in FIG. 2) on an end part 15 of the segment 44 attached. The end part 15 has a bearing surface 17 for a corresponding surface 19 on the knife 22. After loosening the fastening screws 25, the Knife 22 moved in the directions indicated by the double arrow EP are, the bearing surfaces 17,19 slide against each other. This allows the position the separating edge 24 opposite the lateral surface 31 (or the one not shown Set) can be changed. The knife 22 also extends over the full Working width, it is important that the position of the cutting edge opposite the The lateral surface 31 is set or maintained as uniformly as possible over the width. Hood 20 is pivotally mounted on first segment 42 (holding means not shown) and prints with a rubber seal 26 on the one removed from the separation edge 24 Face of the knife 22.

The fiber / air flow FLS in the working gap 10 upstream from the edge 24 is through the peripheral speed and the "surface roughness" of the drum 30 given. The latter parameter is, of course, obtained through the procurement of those not shown Garnish influenced. The set position of the separation edge 24 with respect to the outer surface 31 (or with respect to that supported by the outer surface Clothing) largely determines the proportion of incoming fiber / air flow FLS, the "peeled" by the knife 22, redirected into the separation gap 18 and thereby being removed from the working gap 10. The adjustability is important because the portion to be excreted depends on the processed fiber material and not on can be determined in advance (when designing the machine). But how indicated, the invention is not for use with an adjustable knife limited. The removed portion should be chosen so that the "peeled" air layers relatively many dirt particles (possibly also short fibers) and carry a few good fibers. In most cases, the separating edge 24 becomes clear set closer to the lateral surface 31 than for the one opposite the drum Surface 28 of segment 44 is possible - i.e. the working gap 10 spreads in Region 29 downstream from the separating edge 24 in the radial direction to a degree that depends on the current setting of the knife 22.

In the working gap downstream of the separating edge, the removed ones are therefore "missing" Share of electricity, whereby the remaining share must spread to the expanded To fill the working gap. In the zone Z adjacent to the separating edge 24 Working gap there is negative pressure, which at most a little more (with dirt particles laden) draws air between the separating edge 24 and the lateral surface 31 as is actually desired. In addition, the spreading air flow tends to Vortex formation at the separating edge 24, causing turbulence in the area 29 downstream the separating edge 24 results. Such turbulence can "roll together" or looping fibers around - this creates nits. It can if necessary, also form vortices in the discharge gap itself, which includes air and dirt particles leads back into the working gap.

A first solution to these problems can be found in device 39A in FIG remove, in which the parts already described in connection with Figure 2 were indicated with the same reference numerals. The changed parts are on the one hand the knife 22A and on the other hand the end part 15A of the segment 44. How also seen in Figure 4, the end portion 15A is provided with projections 50 (only a projection 50 visible in Figures 3 and 4), each having a bearing surface 17A have the knife 22A. There are as many projections 50 as fixing screws 25 present and each projection 50 is with a threaded bore 52 for it Provide assigned fixing screw. The width B (Fig. 4) of each projection is but only a fraction of the working width, so that one between the projections 50 Flow channel 54 defined behind the (unchanged) contact surface 19 of the knife becomes. In this case too, the seal 26 touches the end face of the knife 22 thus allows access to the outer end of the channel 54, which is shown in FIG Arrow L is indicated. Air from the surroundings of the formwork can therefore pass through the Channel 54 flow to an adverse vacuum in area 29 downstream of to avoid the separating edge 24A.

The knife 22A is now formed with a head section 14 which is connected to the separating edge 24 is provided. The head section 14 is now also provided with a deflection nose 57 which together with the lower, correspondingly rounded edge 56 on the end part 15A Forms mouth M from channel 54 into working gap 10. Through the nose 57 in air flowing in the gap 10 is deflected in the transport direction. The protrusions 50 preferably do not extend to edge 56 of end portion 15A (see in particular Fig. 4). Each projection 50 has a rounded portion 58 at such a point formed that the partial flows L1 and L2 on both sides of the projection unite in front of the mouth M and as uniformly as possible across the working width can form distributed "air curtain".

Between the edge 24 and the mouth M there is a surface 23 which the Propagation of the working gap 10 in zone Z initiates. This surface 23 can be such be designed so that the aerodynamics at the head 14 is favored.

The number of protrusions is 50 (or the total area size of their bearing surfaces 17A) chosen such that the knife 22A is held stable. This is particularly important because of the very close distances between the separating edge and the one not shown Set on the drum. The through the projections 50 and the fixing screws 25th formed suspension of the knife 22A must ensure that the knife is not in the air currents "flutter". Each projection 50 can be made in one piece with the End part 15A can be formed, but could also be formed separately and on the end part 15A (e.g. by gluing).

In the preferred solution according to the invention, no compressed air is used, but instead rather, the negative pressure prevailing in the working gap is used to To draw in "replacement air". The system is therefore self-adjusting - there is so much air pulled in than is necessary to avoid a significant negative pressure. By the separating edge generated negative pressure zone is therefore by means of a suitable Connection channel connected to an air source.

The ability of an air stream to carry particles and flight depends on the Flow rate. The speed of the current L at the inlet to the Channel 54 should be significantly lower than the speed at the M mouth. Suppose the velocity of the flow approaching the edge is FLS V m / sec, should e.g. the flow velocity at the inlet to channel 54 (stream L) at approx. V / 6 and the speed at the mouth M at approx. V / 2. This can through the design of the channel 54 (selection of the light range or the effective Flow cross section) can be achieved.

The invention enables very narrow adjustments of the edge 24 or the surface 28 opposite the tips of the clothing on the reel 30 (Fig. 1). The distance of the Edge 24 from the clothing tips can e.g. in the range 0.25 to 0.5 mm., and the Distance of the surface 28 from the clothing tips can e.g. 0.8 mm.

The technology or functional principle of dirt removal can be any the known options can be selected. Various devices for use in the card has already been mentioned in the introduction. Other variants are e.g. in EP-A-387 908, EP-A-366 692, US-C-4,400,852, US-C-5,448,800, EP-A-520,958, DE-A-39 02 202, US-C-4,805,267, DE-A-33 31 362, US-C-4,797,980 and Find US-C-5,031,279. The latter script also shows that the same Principles can be applied in the cleaning machine, which of course also applies to the present invention.

3/4 is particularly suitable as a conversion kit for retrofitting one existing card, which is provided with a device according to Figure 2. In the Production of a new card, however, it is possible to provide further optimizations, as will be explained below with reference to FIG. 5. In this case, a profile piece 50 is used (e.g. made of hard anodized aluminum or steel) as a replacement for the end part 15A of the Segment 44 in Figure 3, as well as for the knife 22A, for the hood 20 and also for an end part of the segment 42. The profile piece 50 extends over the whole Working width. It is provided with a longitudinal channel K and with an opening 52 which serves to form the separation gap 18.

The profile piece 50 also has two formwork parts 54, 56, of which one part 54 is provided with a guide surface 58, which together with the drum 30 (in FIG. 5 not shown, cf. 3) limits the working gap 10. The second part 56 serves as a carrier for a guide member 60 which is interchangeably attached to the carrier to after assembly to face the drum or its clothing. As already indicated the element 60 according to the known principles of the technology of such dirt removal devices be formed.

The tapered wall part 62 between the surface 58 and the opening 52 is with a recess 64 which receives a blade blade 66. It is a Fastening means (not shown) are provided so that the separating edge 24 on the sheet 66 adjustable in the directions indicated by the double arrow EP compared to the Working gap can be positioned. The through the sheet 66 from the working gap In this version, deflected air is not directly at the separating edge replaced by new air, but only at the end of the edge remote from the edge 24 Guide surface 58. Between the wall 68 of the profile piece 50 and the adjacent one Formwork element 70, an air supply opening 72 is left open, which in operation connects the working gap with the environment outside the formwork. The distance S of opening 72 from edge 24 is preferably less than 50 mm. The Opening 72 is of course in the form of a "slot" so that the opening stretches across the entire working width. In this case there is no problem with regard to the fixings, since the part 70 and the profile piece 50 are independent can be attached to each other on the drum shields.

The guide surface 58 should be designed and set close to the drum so that no significant turbulence in the downstream of the edge 24 in the working gap remaining fiber / air flow arise. For this purpose, the surface 58 It is advantageous to adjust the drum so closely that it is not essential Spread of the current after the edge 24 is required. This can also make one Pressure drop in the working gap on or downstream of the edge 24 largely be avoided. By maintaining suitable pressure conditions on the Edge 24 the return of air from the opening 18 can be avoided. It is also possible, more precisely the "peelable" portion of the fiber / air flow through the Adjust the blade 66 to adjust. Without this measure it can be under unfavorable conditions result in air circulation within the Opening 52 is created and dirt particles get back into the working gap.

According to an advantageous variant, the inner surface 74 of the profile piece 50 designed in such a way that the discharged air is approximately tangential into the longitudinal channel K enters and then, initially following the inner surface 74, into the area around the center of the Longitudinal channel is guided. This creates a spiral movement of the air, including that carried dirt particles or fibers, as shown schematically in FIG. 6 is shown. The suction is preferably carried out from this central area on one End AE (Fig. 6) of channel K and there is air in the middle at the other end ZE introduced into the channel K. This makes it possible over the entire working width maintain approximately constant recording conditions at the separation gap 18.

Claims (11)

A fiber processing machine with a separation edge (24), wherein both fiber and air are guided past the edge in a substantially predetermined transport direction and dirt particles can be removed from the fiber / air stream (FLS) by means of the edge,
characterized in that at least one measure is taken to limit air turbulence downstream (in the direction of transport) from the edge (24). A fiber processing machine with a separation edge (24), wherein both fiber and air are guided past the edge in a substantially predetermined transport direction and dirt particles can be removed from the fiber / air stream (FLS) by means of the edge,
characterized in that at least one measure is taken to limit or compensate for a pressure drop caused by the air discharge downstream of the edge. A machine according to claim 1 or 2, characterized in that the Machine comprises a rotatable roller (30), the fiber / air flow (FLS) in a working gap (10) between the circumference (31) of the roller (30) and one of it surrounding formwork flows. A machine according to claim 1, 2 or 3, characterized in that the Arrangement is made such that the effective cross section of the working gap (10) undergoes an expansion downstream from the edge (24). A machine according to one of claims 1 to 4, characterized in that the measure mentioned is that means (50, 54; 72) are provided, to allow air to flow into the room downstream from the edge (24). A machine according to claim 5, characterized in that said Means (50,54; 72) are arranged such that air over substantially the can flow in throughout the working width, preferably evenly over the whole working width. A machine according to any one of the preceding claims, characterized characterized in that the edge (24) is formed on an element (22) which in the formwork of the roller (30) is suspended, the suspension (50) being such is formed that enables the required air flow (L) to arise becomes. A machine according to claim 7, characterized in that a Flow channel (54) between the element (22A) and an adjacent one Part (15A) remains free. A machine according to claim 8, characterized in that the suspension (50) bridges the channel (54), ensuring that the Suspension (50) separate partial flows (L1, L2) (again) close together before they flow into the room. A machine according to claim 8 or 9, characterized in that the Flow channel (54) is formed or arranged such that the Incoming air essentially flows into the room Transport direction flows. A machine according to any one of claims 1 to 9, characterized in that the arrangement is self-adjusting with regard to the inflowing air volume.

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